Sample records for summit explosive activity
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Volcano Inflation prior to Gas Explosions at Semeru Volcano, Indonesia
NASA Astrophysics Data System (ADS)
Nishimura, T.; Iguchi, M.; Kawaguchi, R.; Surono, S.; Hendrasto, M.; Rosadi, U.
2010-12-01
Semeru volcano in east Java, Indonesia, is well known to exhibit small vulcanian eruptions at the summit crater. Such eruptive activity stopped on April 2009, but volcanic earthquakes started to occur in August and a lava dome was found in the summit crater on November. Since then, lava sometimes flows downward on the slope and small explosions emitting steams from active crater frequently occur every a few to a few tens of minutes. Since the explosions repeatedly occur with short intervals and the active crater is located close to the summit with an altitude of 3676m, the explosions are considered to originate from the gas (steams) from magma itself in the conduit and not to be caused by interactions of magma with the underground water. We installed a tiltmeter at the summit on March 2010 to study the volcanic eruption mechanisms. The tiltmeter (Pinnacle hybrid type, accuracy of measurement is 1 nrad ) was set at a depth of about 1 m around the summit about 500 m north from the active crater. The data stored every 1 s in the internal memory was uploaded every 6 hours by a small data logger with GPS time correction function. More than one thousand gas explosion events were observed for about 2 weeks. We analyze the tilt records as well as seismic signals recorded at stations of CVGHM, Indonesia. The tilt records clearly show uplift of the summit about 20 to 30 seconds before each explosion. Uplifts before large explosions reach to about 20 - 30 n rad, which is almost equivalent to the volume increase of about 100 m^3 beneath the crater. To examine the eruption magnitude dependence on the uplift, we classify the eruptions into five groups based on the amplitudes of seismograms associated with explosions. We stack the tilt records for these groups to reduce noises in the signals and to get general characteristics of the volcano inflations. The results show that the amplitudes of uplifts are almost proportional to the amplitudes of explosion earthquakes while the preceding time of uplift is almost constant (20 s - 30 s). This implies that the inflation rate controls the magnitude of gas explosions. The observed preceding time of inflation prior to gas explosions are much shorter than those for the inflations before magmatic explosions (Nishi et al., 2007; Iguchi et al., 2008), which suggests that the pressurization processes in shallow conduit for gas explosions are different from that for explosions emitting ashes.
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Catalog of Tephra Samples from Kilauea's Summit Eruption, March-December 2008
Wooten, Kelly M.; Thornber, Carl R.; Orr, Tim R.; Ellis, Jennifer F.; Trusdell, Frank A.
2009-01-01
The opening of a new vent within Halema'uma'u Crater in March 2008 ended a 26-year period of no eruptive activity at the summit of Kilauea Volcano. It also heralded the first explosive activity at Kilauea's summit since 1924 and the first of eight discrete explosive events in 2008. At the onset of the eruption, the Hawaiian Volcano Observatory (HVO) initiated a rigorous program of sample collection to provide a temporally constrained suite of tephra samples for petrographic, geochemical, and isotopic studies. Petrologic studies help us understand conditions of magma generation at depth; processes related to transport, storage, and mixing of magma within the shallow summit region; and specific circumstances leading to explosive eruptions. This report provides a catalog of tephra samples erupted at Kilauea's summit from March 19, 2008, through the end of 2008. The Kilauea 2008 Summit Sample Catalog is tabulated in the accompanying Microsoft Excel file, of2009-1134.xls (four file types linked on right). The worksheet in this file provides sampling information and sample descriptions. Contextual information for this catalog is provided below and includes (1) a narrative of 2008 summit eruptive activity, (2) a description of sample collection methods, (3) a scheme for characterizing a diverse range in tephra lithology, and (4) an explanation of each category of sample information (column headers) in the Microsoft Excel worksheet.
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Cycles of explosive and effusive eruptions at Kīlauea Volcano, Hawai‘i
Swanson, Don; Rose, Timothy R.; Mucek, Adonara E; Garcia, Michael O.; Fiske, Richard S.; Mastin, Larry G.
2014-01-01
The subaerial eruptive activity at Kīlauea Volcano (Hawai‘i) for the past 2500 yr can be divided into 3 dominantly effusive and 2 dominantly explosive periods, each lasting several centuries. The prevailing style of eruption for 60% of this time was explosive, manifested by repeated phreatic and phreatomagmatic activity in a deep summit caldera. During dominantly explosive periods, the magma supply rate to the shallow storage volume beneath the summit dropped to only a few percent of that during mainly effusive periods. The frequency and duration of explosive activity are contrary to the popular impression that Kīlauea is almost unceasingly effusive. Explosive activity apparently correlates with the presence of a caldera intersecting the water table. The decrease in magma supply rate may result in caldera collapse, because erupted or intruded magma is not replaced. Glasses with unusually high MgO, TiO2, and K2O compositions occur only in explosive tephra (and one related lava flow) and are consistent with disruption of the shallow reservoir complex during caldera formation. Kīlauea is a complex, modulated system in which melting rate, supply rate, conduit stability (in both mantle and crust), reservoir geometry, water table, and many other factors interact with one another. The hazards associated with explosive activity at Kīlauea’s summit would have major impact on local society if a future dominantly explosive period were to last several centuries. The association of lowered magma supply, caldera formation, and explosive activity might characterize other basaltic volcanoes, but has not been recognized.
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Mechanism of explosive eruptions of Kilauea Volcano, Hawaii
Dvorak, J.J.
1992-01-01
A small explosive eruption of Kilauea Volcano, Hawaii, occurred in May 1924. The eruption was preceded by rapid draining of a lava lake and transfer of a large volume of magma from the summit reservoir to the east rift zone. This lowered the magma column, which reduced hydrostatic pressure beneath Halemaumau and allowed groundwater to flow rapidly into areas of hot rock, producing a phreatic eruption. A comparison with other events at Kilauea shows that the transfer of a large volume of magma out of the summit reservoir is not sufficient to produce a phreatic eruption. For example, the volume transferred at the beginning of explosive activity in May 1924 was less than the volumes transferred in March 1955 and January-February 1960, when no explosive activity occurred. Likewise, draining of a lava lake and deepening of the floor of Halemaumau, which occurred in May 1922 and August 1923, were not sufficient to produce explosive activity. A phreatic eruption of Kilauea requires both the transfer of a large volume of magma from the summit reservoir and the rapid removal of magma from near the surface, where the surrounding rocks have been heated to a sufficient temperature to produce steam explosions when suddenly contacted by groundwater. ?? 1992 Springer-Verlag.
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Acoustic and tephra records of explosive eruptions at West Mata submarine volcano, NE Lau Basin
NASA Astrophysics Data System (ADS)
Dziak, R. P.; Bohnenstiehl, D. R.; Baker, E. T.; Matsumoto, H.; Caplan-Auerbach, J.; Mack, C. J.; Embley, R. W.; Merle, S. G.; Walker, S. L.; Lau, T. A.
2013-12-01
West Mata is a 1200 m deep submarine volcano where explosive boninite eruptions were directly observed in May 2009. Here we present long-term acoustic and tephra records of West Mata explosion activity from three deployments of hydrophone and particle sensor moorings beginning on 8 January 2009. These records provide insights into the character of explosive magma degassing occurring at the volcano's summit vent until the decline and eventual cessation of the eruption during late 2010 and early 2011. The detailed acoustic records show three types of volcanic signals, 1) discrete explosions, 2) diffuse explosions, and 3) volcanic tremor. Discrete explosions are short duration, high amplitude broad-band signals caused by rapid gas bubble release. Diffuse signals are likely a result of 'trap-door' explosions where a quench cap of cooled lava forms over the magmatic vent but gas pressure builds underneath the cap. This pressure eventually causes the cap to breach and gas is explosively released until pressure reduces and the cap once again forms. Volcanic tremor is typified by narrow-band, long-duration signals with overtones, as well as narrow-band tones that vary frequency over time between 60-100 Hz. The harmonic tremor is thought to be caused by modulation of rapid, short duration gas explosion pulses and not a magma resonance phenomenon. The variable frequency tones may be caused by focused degassing or hydrothermal fluid flow from a narrow volcanic vent or conduit. High frequency (>30 Hz) tremor-like bands of energy are a result of interference caused by multipath wide-band signals, including sea-surface reflected acoustic phases, that arrive at the hydrophone with small time delays. Acoustic data suggest that eruption velocities for a single explosion range from 4-50 m s-1, although synchronous arrival of explosion signals has complicated our efforts to estimate long-term gas flux. Single explosions exhibit ~4-40 m3 s-1 of total volume flux (gas and rock) but with durations of only 20-30 ms. Interestingly, explosion activity increased at West Mata for several months, observed at more distant hydrophone stations, following the September 2009 8.1 Mw Samoan earthquake. The tephra and hydrophone data were only synchronously recorded from January to May 2010, but these data indicate a repeated record of summit explosions followed by down flank debris flows, an important process in the construction of the volcanic edifice. Bathymetric differencing between 2010 and 2011 shows two large negative anomalies at the summit and a broad positive anomaly on the east flank, interpreted as a major slump that removed part of the summit during the final magma withdrawal related to formation of the summit pit crater.
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NASA Astrophysics Data System (ADS)
Ohminato, T.; Kaneko, T.; Koyama, T.; Watanabe, A.; Takeo, M.; Iguchi, M.
2011-12-01
Observations in the vicinity of summit area of active volcanoes are important not only for understanding physical processes in the volcanic conduit but also for eruption prediction and volcanic hazards mitigation. It is, however, challenging to install observation sensors near active vents because of the danger of sudden eruptions. We have been developing a volcano observation system based on an unmanned aerial vehicle (UAV) for safe observations near active volcanic vents. We deployed an unmanned autonomous helicopter which can aviate autonomously along a previously programmed path within a meter accuracy using real-time kinematics differential GPS equipment. The maximum flight time, flight distance, and payload are 90 minutes, 5km, and 10kg, respectively. By using the UAV, we installed seismic stations at the summit area of Sakurajima volcano, Japan. Since 2006, explosive eruptions have been continuing at the reopened Showa crater at the eastern flank near the summit of Sakurajima. Entering the area within 2 km from the active craters is prohibited, and thus there were no observation station in the summit area. From November 2nd to 12th, 2009, and from November 2nd to 12th, 2010, we conducted seismic station installation in Sakurajima summit area using UAV and successfully installed four seismic stations within 2km from the active craters. Since the installation of the seismic stations, we have succeeded in acquiring waveform data accompanying more than 500 moderate eruptions at Showa-crater. Except for the mechanical resonance contamination at 35Hz, the recorded waveforms are as good as that recorded at permanent stations in Sakurajima. Since the beginning of the observation in the vicinity of the summit crater, the normalized amplitudes of the signals accompanying eruptions at Showa crater had been almost steady. However, after early April 2011, gradual increase of the normalized amplitude started, and this increasing trend is continuing at the time of the abstract submission. This increasing trend of the normalized amplitude strongly suggests upward migration of the source of the explosive eruptions at Showa-crater. The upward migration may suggest further intensification of the activity of Sakurajima in the near future.
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The activity of the Colima volcano and morphological changes in the summit between 2004 and 2013
NASA Astrophysics Data System (ADS)
Suarez-Plascencia, C.; Nunez-Cornu, F. J.; Camarena Garcia, M. A.
2013-05-01
Colima Volcano, located in the West of the Volcanic Mexican Belt (19° 30.696 N, 103° 37.026 W), has shown a new cycle of explosive activity beginning May 30 1999, and reaching its maximum in March-April of 2005 and January 2013. In the 2005 the explosive activity increased gradually, having the largest event on May 23, when a new dome was created. Hours later this dome was destroyed by a strong explosion, forming an ash column 5.6 km high with subsequent pyroclastic flows that reached a distance of 4.2 km flowing along the ravines of the South sector. On May 30 the most intense explosion in 1999 occurred, when the plume reached heights in excess of 4.4 km above the crater, and pyroclastic flows were created. On the same year in July two explosive events occurred of characteristics similar to those in May. These constant explosions caused continuous morphological changes in the summit, the most significant being the collapse of the North and South walls of the crater, in the first week of June of 2005, and the creation of a new crater in July. In 2006 the most significant explosive activity took place during April, May and July, when the eruptive columns reached heights of more than 1500 meters above the crater, occasionally forming small pyroclastic flows. In May of 2007 morphological changes were observed in the summit. Among them a crater explosion on the East side, a dome was formed on the West side, with 20 m in high and 50 m in diameter. Since the end of 2008 to December of 2012 the volcano remained calm, with a dome diameter of 220 m and height of 60 m, in January 2013 three explosions occurred, destroying the dome and throwing a volume of 1.5 million cubic meters. The eruptive column reached a height of 3000 above the crater. It reported light ashfall to the NE to 100 km away from the volcano. The explosive events continue to date, but they have diminished in size and intensity. This activity was similar to the one observed in 1902-1903 and reported by Severo Diaz and J.M. Arreola (1906), but without reaching the maximum levels of activity reported for 1903, where it had levels of three to five maximum explosive events per day. The photographs and the digital mapping have provided detailed information to quantify the dynamic evolution of the volcanic structures that developed on the summit of the volcano in the course of the last for years. The cartographic and database information obtained will be the basis for updating the Operational Plan of the Colima Volcano by the State Civil & Fire Protection Unit of Jalisco, Mexico, and the urban development plans of surrounding municipalities, in order to reduce their vulnerability to the hazards of the volcanic activity.
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Analyses of Etna Eruptive Activity From 18th Century and Characterization of Flank Eruptions
NASA Astrophysics Data System (ADS)
del Carlo, P.; Branca, S.; Coltelli, M.
2003-12-01
Etna explosive activity has usually been considered subordinate with respect to the effusive eruptions. Nevertheless, in the last decade and overall after the 2001 and 2002 flank eruptions, explosive activity has drawn the attention of the scientific and politic communities owing to the damages that the long-lasting ash fall caused to Sicily's economy. We analyzed the eruptions from the 18th century to find some analogous behavior of Etna in the past. A study of the Etna historical record (Branca and Del Carlo, 2003) evidenced that after the 1727 eruption, there are no more errors in the attribution of the year of the eruption. Furthermore from this time on, the scientific quality of the chronicles allowed us to obtain volcanological information and to estimate the magnitude of the major explosive events. The main goal of this work was to characterize the different typologies of Etna eruptions in the last three centuries. Meanwhile, we have tried to find the possible relationship between the two kinds of activity (explosive and effusive) in order to understand the complexity of the eruptive phenomena and define the short-term behavior of Etna. On the base of the predominance of the eruptive typology (effusive or explosive) we have classified the flank eruptions in three classes: i) Type 1: almost purely effusive; ii) Type 2: the intensity of explosive activity comparable with the effusive; iii) Type 3: almost purely explosive with minor lava effusion (only the 1763 La Montagnola and 2002 eruptions belong to this class). Long-lasting explosive activity is produced by flank eruptions with continuous ash emission and prolonged fallout on the flanks (e.g. 1763, 1811, 1852-53, 1886, 1892, 2001 and 2002 eruptions). At summit craters continuous activity is weaker, whereas the strongest explosive eruptions are short-lived events. Furthermore, from the 18th to 20th century there were several years of intense and discontinuous summit explosive activity, from high strombolian to fire fountain. This activity produced abundant ash fall in the whole volcano area reaching the Calabria region and Malta Island. Generally, some of these periods preceded important flank eruptions. Concerning the occurrence of the higher magnitude explosive events, we observe that at least one subplinian eruption occurred both in the 18th and 19th centuries. In the 20th century the increased quality of the scientific reports has allowed to recognize 6 subplinian eruptions from summit craters.
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Kīlauea summit eruption—Lava returns to Halemaʻumaʻu
Babb, Janet L.; Wessells, Stephen M.; Neal, Christina A.
2017-10-06
In March 2008, a new volcanic vent opened within Halemaʻumaʻu, a crater at the summit of Kīlauea Volcano in Hawaiʻi Volcanoes National Park on the Island of Hawaiʻi. This new vent is one of two ongoing eruptions on the volcano. The other is on Kīlauea’s East Rift Zone, where vents have been erupting nearly nonstop since 1983. The duration of these simultaneous summit and rift zone eruptions on Kīlauea is unmatched in at least 200 years.Since 2008, Kīlauea’s summit eruption has consisted of continuous degassing, occasional explosive events, and an active, circulating lava lake. Because of ongoing volcanic hazards associated with the summit vent, including the emission of high levels of sulfur dioxide gas and fragments of hot lava and rock explosively hurled onto the crater rim, the area around Halemaʻumaʻu remains closed to the public as of 2017.Through historical photos of past Halemaʻumaʻu eruptions and stunning 4K imagery of the current eruption, this 24-minute program tells the story of Kīlauea Volcano’s summit lava lake—now one of the two largest lava lakes in the world. It begins with a Hawaiian chant that expresses traditional observations of a bubbling lava lake and reflects the connections between science and culture that continue on Kīlauea today.The video briefly recounts the eruptive history of Halemaʻumaʻu and describes the formation and continued growth of the current summit vent and lava lake. It features USGS Hawaiian Volcano Observatory scientists sharing their insights on the summit eruption—how they monitor the lava lake, how and why the lake level rises and falls, why explosive events occur, the connection between Kīlauea’s ongoing summit and East Rift Zone eruptions, and the impacts of the summit eruption on the Island of Hawaiʻi and beyond. The video is also available at the following U.S. Geological Survey Multimedia Gallery link (video hosted on YouTube): Kīlauea summit eruption—Lava returns to Halemaʻumaʻu
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Recent uplift and hydrothermal activity at Tangkuban Parahu volcano, west Java, Indonesia
Dvorak, J.; Matahelumual, J.; Okamura, A.T.; Said, H.; Casadevall, T.J.; Mulyadi, D.
1990-01-01
Tangkuban Parahu is an active stratovolcano located 17 km north of the city of Bandung in the province west Java, Indonesia. All historical eruptive activity at this volcano has been confined to a complex of explosive summit craters. About a dozen eruptions-mostly phreatic events- and 15 other periods of unrest, indicated by earthquakes or increased thermal activity, have been noted since 1829. The last magmatic eruption occurred in 1910. In late 1983, several small phreatic explosions originated from one of the summit craters. More recently, increased hydrothermal and earthquake activity occurred from late 1985 through 1986. Tilt measurements, using a spirit-level technique, have been made every few months since February 1981 in the summit region and along the south and east flanks of the volcano. Measurements made in the summit region indicated uplift since the start of these measurements through at least 1986. From 1981 to 1983, the average tilt rate at the edges of the summit craters was 40-50 microradians per year. After the 1983 phreatic activity, the tilt rate decreased by about a factor of five. Trilateration surveys across the summit craters and on the east flank of the volcano were conducted in 1983 and 1986. Most line length changes measured during this three-year period did not exceed the expected uncertainty of the technique (4 ppm). The lack of measurable horizontal strain across the summit craters seems to contradict the several years of tilt measurements. Using a point source of dilation in an elastic half-space to model tilt measurements, the pressure center at Tangkuban Parahu is located about 1.5 km beneath the southern part of the summit craters. This is beneath the epicentral area of an earthquake swarm that occurred in late 1983. The average rate in the volume of uplift from 1981 to 1983 was 3 million m3 per year; from 1983 to 1986 it averaged about 0.4 million m3 per year. Possible causes for this uplift are increased pressure within a very shallow magma body or heating and expansion of a confined aquifier. ?? 1990 Springer-Verlag.
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Multispectral Observations of Explosive Gas Emissions from Santiaguito, Guatemala
NASA Astrophysics Data System (ADS)
Carn, S. A.; Watson, M.; Thomas, H.; Rodriguez, L. A.; Campion, R.; Prata, F. J.
2016-12-01
Santiaguito volcano, Guatemala, has been persistently active for decades, producing frequent explosions from its actively growing lava dome. Repeated release of volcanic gases contains information about conduit processes during the cyclical explosions at Santiaguito, but the composition of the gas phase and the amount of volatiles released in each explosion remains poorly constrained. In addition to its persistent activity, Santiaguito offers an exceptional opportunity to investigate lava dome degassing processes since the upper surface of the active lava dome can be viewed from the summit of neighboring Santa Maria. In January 2016 we conducted multi-spectral observations of Santiaguito's explosive eruption plumes and passive degassing from multiple perspectives as part of the first NSF-sponsored `Workshop on Volcanoes' instrument deployment. Gas measurements included open-path Fourier-Transform infrared (OP-FTIR) spectroscopy from the Santa Maria summit, coincident with ultraviolet (UV) and infrared (IR) camera and UV Differential Optical Absorption Spectroscopy (DOAS) from the El Mirador site below Santiaguito's active Caliente lava dome. Using the OP-FTIR in passive mode with the Caliente lava dome as the source of IR radiation, we were able to collect IR spectra at high temporal resolution prior to and during two explosions of Santiaguito on 7-8 January, with volcanic SO2 and H2O emissions detected. UV and IR camera data provide constraints on the total SO2 burden in the emissions (and potentially the volcanic ash burden), which coupled with the FTIR gas ratios provides new constraints on the mass and composition of volatiles driving explosions at Santiaguito. All gas measurements indicate significant volatile release during explosions with limited degassing during repose periods. In this presentation we will present ongoing analysis of the unique Santiaguito gas dataset including estimation of the total volatile mass released in explosions and an intercomparison of SO2 amounts recorded by the UV and IR instruments.
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Harpel, C.J.; Kyle, P.R.; Esser, R.P.; McIntosh, W.C.; Caldwell, D.A.
2004-01-01
Eruptive activity has occurred in the summit region of Mount Erebus over the last 95 ky, and has included numerous lava flows and small explosive eruptions, at least one plinian eruption, and at least one and probably two caldera-forming events. Furnace and laser step-heating 40Ar/39Ar ages have been determined for 16 summit lava flows and three englacial tephra layers erupted from Mount Erebus. The summit region is composed of at least one or possibly two superimposed calderas that have been filled by post-caldera lava flows ranging in age from 17 ?? 8 to 1 ?? 5 ka. Dated pre-caldera summit flows display two age populations at 95 ?? 9 to 76 ?? 4 ka and 27 ?? 3 to 21 ??4 ka of samples with tephriphonolite and phonolite compositions, respectively. A caldera-collapse event occurred between 25 and 11 ka. An older caldera-collapse event is likely to have occurred between 80 and 24 ka. Two englacial tephra layers from the flanks of Mount Erebus have been dated at 71 ?? 5 and 15 ?? 4 ka. These layers stratigraphically bracket 14 undated tephra layers, and predate 19 undated tephra layers, indicating that small-scale explosive activity has occurred throughout the late Pleistocene and Holocene eruptive history of Mount Erebus. A distal, englacial plinian-fall tephra sample has an age of 39 ?? 6 ka and may have been associated with the older of the two caldera-collapse events. A shift in magma composition from tephriphonolite to phonolite occurred at around 36 ka. ?? Springer-Verlag 2004.
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Earth Observations taken by the Expedition 13 crew
2006-08-02
ISS013-E-62714 (2 Aug. 2006) --- Mt. Etna Summit Plumes, Sicily is featured in this image photographed by an Expedition 13 crewmember on the International Space Station. One of the most consistently active volcanoes in the world is Sicily's Mt. Etna, which has a historical record of eruptions dating back to 1500 B.C. This image captures plumes of steam and possible minor ash originating from summit craters on the mountain -- the Northeast Crater and Central Crater, which includes two secondary craters (Voragine and Bocca Nuova). Explosions were heard from the rim of the Northeast Crater on July 26, and scientists suspect that these plumes are a continuation of that activity. The massive 3350 meter high volcano is located approximately 24 kilometers to the north of Catania, the second largest city in Sicily, and dominates the northern skyline. Much of Etna's surface is comprised of numerous generations of dark basaltic lava flows, as can be seen extended outwards from the summit craters. Fertile soils developed on older flows are marked by green vegetation. While the current explosive eruptions of Etna tend to occur at the summit, lava flows generally erupt through fissures lower down on the flanks of the volcano. Many of the lava flow vents are marked by cinder cones on the flanks of Mt. Etna. Scientists have noted evidence of larger eruptive events as well. The Valle Del Bove to the south-southeast of the summit is a caldera formed by the emptying of a subsurface magma chamber during a large eruptive event -- once the magma chamber was emptied, the overlaying roof material collapsed downwards.
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Thermal imaging and analysis of short-lived Vulcanian explosions at Volcán de Colima, Mexico
NASA Astrophysics Data System (ADS)
Webb, Erica B.; Varley, Nick R.; Pyle, David M.; Mather, Tamsin A.
2014-05-01
Vulcanian explosions present a major hazard at many active volcanoes, but they also provide useful insights into the underlying behaviour of the volcanic system and therefore require close monitoring. Thermal infrared cameras are an effective tool for imaging Vulcanian explosion plumes since they capture detailed temperature information, and can reveal the internal dynamics of the plume-forming explosions. High spatial resolution thermal images of 200 small to moderate sized Vulcanian explosions from the summit crater of Volcán de Colima, Mexico, recorded between 2006 and 2011, were analysed to distinguish different event types and develop an explosion classification scheme. Explosions display a broad spectrum of sizes and characteristics, ranging between two typical end-members: “large-impulsive” events producing rapidly ascending explosion plumes up to heights of 600-1600 m above the crater rim, and “small-diffusive” events with plumes restricted to heights < 600 m. Most explosion plumes comprise a steady “gas-thrust” feeder plume below a convecting plume front. Others, that lack sufficient kinetic energy, rise buoyantly throughout the explosion, with steady buoyant ascent velocities ranging from ~ 1 m s- 1 to ~ 29 m s- 1. A time-series of thermal imagery throughout the period 2006-2011 reveals a weak relationship between apparent plume temperatures and lava dome extrusion, with the highest explosion temperatures coinciding with the onset of dome growth in early 2007. Temporal variations in the source locations of explosions across the summit crater are also identified and appear to show a close relationship to the patterns of lava dome growth and thermal evolution, with explosion source locations associated with the highest temperature thermal features.
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NASA Astrophysics Data System (ADS)
Ohminato, T.; Kaneko, T.; Koyama, T.; Yasuda, A.; Watanabe, A.; Takeo, M.; Honda, Y.; Kajiwara, K.; Kanda, W.; Iguchi, M.; Yanagisawa, T.
2010-12-01
Observations in the vicinity of summit area of active volcanoes are important not only for understanding physical processes in the volcanic conduit but also for eruption prediction and volcanic hazards mitigation. It is, however, challenging to install observation sensors near active vents because of the danger of sudden eruptions. We need safe and efficient ways of installing sensors near the summit of active volcanoes. We have been developing an volcano observation system based on an unmanned autonomous vehicle (UAV) for risk-free volcano observations. Our UAV is an unmanned autonomous helicopter manufactured by Yamaha-Motor Co., Ltd. The UAV is 3.6m long and weighs 84kg with maximum payload of 10kg. The UAV can aviate autonomously along a previously programmed path within a meter accuracy using real-time kinematics differential GPS equipment. The maximum flight time and distance from the operator are 90 minutes and 5km, respectively. We have developed various types of volcano observation techniques adequate for the UAV, such as aeromagnetic survey, taking infrared and visible images from onboard high-resolution cameras, volcanic ash sampling in the vicinity of active vents. Recently, we have developed an earthquake observation module (EOM), which is exclusively designed for the UAV installation in the vicinity of active volcanic vent. In order to meet the various requirements for UAV installation, the EOM is very compact, light-weight (5-6kg), and is solar-powered. It is equipped with GPS for timing, a communication device using cellular-phone network, and triaxial accelerometers. Our first application of the EOM installation using the UAV is one of the most active volcanoes in Japan, Sakurajima volcano. Since 2006, explosive eruptions have been continuing at the reopened Showa crater at the eastern flank near the summit of Sakurajima. Entering the area within 2 km from the active craters is prohibited, and thus there were no observation station in the vicinity of active vents at the summit area. From November 2nd to 12th, 2009, we could successfully install four EOMs in the summit area within 2km from the active craters by using the UAV. Although the state of communication was not perfect since the installation points were outside of the service area of the cellular-phone network, we succeeded in retrieving the seismic waveform data accompanying moderate eruptions at Showa crater. Except for contamination by the mechanical resonance of the frame of EOM around 35 Hz, the recorded waveforms of the explosive eruptions are as good as the best permanent stations in Sakurajima. Preliminary results of the analyses show that the source location distribution of the explosion earthquakes at Showa crater is improved by the inclusion of the near source stations newly installed by using the UAV.
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Coppola, Diego; Macedo, Orlando; Ramos, Domingo; Finizola, Anthony; Delle Donne, Dario; del Carpio, Jose; White, Randall A.; McCausland, Wendy; Centeno, Riky; Rivera, Marco; Apaza, Fredy; Ccallata, Beto; Chilo, Wilmer; Cigolini, Corrado; Laiolo, Marco; Lazarte, Ivonne; Machaca, Roger; Masias, Pablo; Ortega, Mayra; Puma, Nino; Taipe, Edú
2015-01-01
After 3 years of mild gases emissions, the Ubinas volcano entered in a new eruptive phase on September 2nd, 2013. The MIROVA system (a space-based volcanic hot-spot detection system), allowed us to detect in near real time the thermal emissions associated with the eruption and provided early evidence of magma extrusion within the deep summit crater. By combining IR data with plume height, sulfur emissions, hot spring temperatures and seismic activity, we interpret the thermal output detected over Ubinas in terms of extrusion rates associated to the eruption. We suggest that the 2013–2014 eruptive crisis can be subdivided into three main phases: (i) shallow magma intrusion inside the edifice, (ii) extrusion and growing of a lava plug at the bottom of the summit crater coupled with increasing explosive activity and finally, (iii) disruption of the lava plug and gradual decline of the explosive activity. The occurrence of the 8.2 Mw Iquique (Chile) earthquake (365 km away from Ubinas) on April 1st, 2014, may have perturbed most of the analyzed parameters, suggesting a prompt interaction with the ongoing volcanic activity. In particular, the analysis of thermal and seismic datasets shows that the earthquake may have promoted the most intense thermal and explosive phase that culminated in a major explosion on April 19th, 2014.These results reveal the efficiency of space-based thermal observations in detecting the extrusion of hot magma within deep volcanic craters and in tracking its evolution. We emphasize that, in combination with other geophysical and geochemical datasets, MIROVA is an essential tool for monitoring remote volcanoes with rather difficult accessibility, like those of the Andes that reach remarkably high altitudes.
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Earth Observations taken by the Expedition 13 crew
2006-08-14
ISS013-E-66488 (14 Aug. 2006) --- Ash cloud from Ubinas Volcano, Peru is featured in this image photographed by an Expedition 13 crewmember on the International Space Station (ISS). Subduction of the Nazca tectonic plate along the western coast of South America forms the high Peruvian Andes, and also produces magma feeding a chain of historically active volcanoes along the western front of the mountains. The most active of these volcanoes in Peru is Ubinas. A typical steep-sided stratovolcano comprised primarily of layers of silica-rich lava flows, it has a summit elevation of 5,672 meters. The volcanic cone appears distinctively truncated or flat-topped in profile -- the result of a relatively small eruption that evacuated a magma reservoir near the summit. Following removal of the magma, the summit material collapsed downwards to form the current 1.4 kilometer-wide summit caldera. This oblique image (looking at an angle from the ISS) captures an ash cloud first observed on satellite imagery at 11:00 GMT on Aug. 14, 2006; this image was acquired one hour and 45 minutes later. The ash cloud resulted in the issuing of an aviation hazard warning by the Buenos Aires Volcanic Ash Advisory Center. Modern activity at Ubinas is characterized by these minor to moderate explosive eruptions of ash and larger pumice - a volcanic rock characterized by low density and high proportion of gas bubbles formed as the explosively-erupted parent lava cools during its transit through the air. These materials blanket the volcanic cone and surrounding area, giving this image an overall gray appearance. Shadowing of the western flank of Ubinas throws several lava flows into sharp relief, and highlights the steep slopes at the flow fronts -- a common characteristic of silica-rich, thick, and slow-moving lavas. NASA researchers note that the most recent major eruption of Ubinas occurred in 1969, however the historical record of activity extends back to the 16th century.
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NASA Astrophysics Data System (ADS)
Bagnardi, M.; Eggers, A.; Battaglia, M.; Poland, M.; Johnson, D.
2008-12-01
Since January 3 1983, Kilauea Volcano, Hawaii, has erupted almost continuously from vents on the volcano's east rift zone. On March 19, 2008, an explosion at Halema'uma'u Crater, within the summit caldera of Kilauea, marked the opening of a second eruptive vent on the volcano. The east rift vent at Pu'u'O'o and the summit vent at Halema'uma'u continue to be active as of August 2008, marking the longest interval in Kilauea's recorded history of eruptive activity on the volcano. Four gravity surveys with a network covering Kilauea's summit area have been performed during 1975-2003. We reoccupied this 45-station network in January and July 2008 with three portable LaCoste-Romberg gravimeters (G209, G615 and EG026) using a double-looping procedure. These two most recent gravity surveys span the onset of summit eruptive activity. The micro-gravity data set, combined with existing geodetic data from leveling, GPS, EDM, and InSAR, allow us to investigate and model the shallow magma system under the summit caldera to roughly constrain its shape, position, volume change and density, and better understand its long and short term evolution. We corrected for the effect of vertical deformation on gravity data (the so-called free-air effect) using uplift measurements from annual surveys performed by the USGS Hawaiian Volcano Observatory. Preliminary analysis of this record, which covers more than 30 years, indicates a persistent positive residual gravity anomaly located at the southeast margin of Halema'uma'u Crater, very close to the location of the new summit eruptive vent. This anomaly suggests a long term mass accumulation beneath the summit caldera.
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NASA Astrophysics Data System (ADS)
Richter, Nicole; Poland, Michael P.; Lundgren, Paul R.
2013-04-01
On 19 March 2008, a small explosive eruption at the summit of Kīlauea Volcano, Hawai`i, heralded the formation of a new vent along the east wall of Halema`uma`u Crater. In the ensuing years, the vent widened due to collapses of the unstable rim and conduit wall; some collapses impacted an actively circulating lava pond and resulted in small explosive events. We used synthetic aperture radar data collected by the TerraSAR-X satellite, a joint venture between the German Aerospace Center (DLR) and EADS Astrium, to identify and analyze small-scale surface deformation around the new vent during 2008-2012. Lidar data were used to construct a digital elevation model to correct for topographic phase, allowing us to generate differential interferograms with a spatial resolution of about 3 m in Kīlauea's summit area. These interferograms reveal subsidence within about 100 m of the rim of the vent. Small baseline subset time series analysis suggests that the subsidence rate is not constant and, over time, may provide an indication of vent stability and potential for rim and wall collapse—information with obvious hazard implications. The deformation is not currently detectable by other space- or ground-based techniques.
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Richter, Nichole; Poland, Michael P.; Lundgren, Paul R.
2013-01-01
On 19 March 2008, a small explosive eruption at the summit of Kīlauea Volcano, Hawai‘i, heralded the formation of a new vent along the east wall of Halema‘uma‘u Crater. In the ensuing years, the vent widened due to collapses of the unstable rim and conduit wall; some collapses impacted an actively circulating lava pond and resulted in small explosive events. We used synthetic aperture radar data collected by the TerraSAR-X satellite, a joint venture between the German Aerospace Center (DLR) and EADS Astrium, to identify and analyze small-scale surface deformation around the new vent during 2008-2012. Lidar data were used to construct a digital elevation model to correct for topographic phase, allowing us to generate differential interferograms with a spatial resolution of about 3 m in Kīlauea's summit area. These interferograms reveal subsidence within about 100 m of the rim of the vent. Small baseline subset time series analysis suggests that the subsidence rate is not constant and, over time, may provide an indication of vent stability and potential for rim and wall collapse -- information with obvious hazard implications. The deformation is not currently detectable by other space- or ground-based techniques.
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NASA Astrophysics Data System (ADS)
Lorenzo-Merino, A.; Guilbaud, M.-N.; Roberge, J.
2018-03-01
Pelado volcano is a typical example of an andesitic Mexican shield with a summital scoria cone. It erupted ca. 10 ka in the central part of an elevated plateau in what is today the southern part of Mexico City. The volcano forms a roughly circular, 10-km wide lava shield with two summital cones, surrounded by up to 2.7-m thick tephra deposits preserved up to a distance of 3 km beyond the shield. New cartographic, stratigraphic, granulometric, and componentry data indicate that Pelado volcano was the product of a single, continuous eruption marked by three stages. In the early stage, a > 1.5-km long fissure opened and was active with mild explosive activity. Intermediate and late stages were mostly effusive and associated with the formation of a 250-m high lava shield. Nevertheless, during these stages, the emission of lava alternated and/or coexisted with highly explosive events that deposited a widespread tephra blanket. In the intermediate stage, multiple vents were active along the fissure, but activity was centered at the main cone during the late stage. The final activity was purely effusive. The volcano emitted > 0.9 km3 dense-rock equivalent (DRE) of tephra and up to 5.6 km3 DRE of lavas. Pelado shares various features with documented "violent Strombolian" eruptions, including a high fragmentation index, large dispersal area, occurrence of plate tephra, high eruptive column, and simultaneous explosive and effusive activity. Our results suggest that the associated hazards (mostly tephra fallout and emplacement of lava) would seriously affect areas located up to 25 km from the vent for fallout and 5 km from the vent for lava, an important issue for large cities built near or on potentially active zones, such as Mexico City.
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NASA Astrophysics Data System (ADS)
Coltelli, Mauro; Biale, Emilio; Ciancitto, Francesco; Pecora, Emilio; Prestifilippo, Michele
2014-05-01
Since 1994 a video-surveillance camera located on a peak just above the active volcanic vents of Stromboli island records the explosive activity of one of the few volcanoes on the world performing a persistent eruptive activity. From 2003, after one of the larger lava flow eruption of the last century, the video-surveillance system was enhanced with more stations having both thermal and visual cameras. The video-surveillance helps volcanologists to characterize the mild explosive activity of Stromboli named Strombolian and to distinguish between the frequent "ordinary" Strombolian explosions and the occasional "extraordinary" strong Strombolian explosions that periodically occur. A new class of extraordinary explosions was discovered filling the gap between the ordinary activity and the strong explosions named major explosions when the tephra fallout covers large areas on the volcano summit and paroxysmal ones when the bombs fall down to the inhabited area along the coast of the island. In order to quantify the trend of the ordinary Strombolian explosions and to understand the occurring of the extraordinary strong Strombolian explosions a computer assisted image analysis was developed to process the huge amount of thermal and visual images recorded in several years. The results of this complex analysis allow us to clarify the processes occurring in the upper plumbing system where the pockets/trains of bubbles coalesce and move into the active vent conduits producing the ordinary Strombolian activity, and to infer the process into the deeper part of the plumbing system where new magma supply and its evolution lead to the formation of the extraordinary strong Strombolian explosions.
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The first five years of Kīlauea’s summit eruption in Halema‘uma‘u Crater, 2008–2013
Patrick, Matthew R.; Orr, Tim R.; Sutton, A.J.; Elias, Tamar; Swanson, Donald A.
2013-01-01
The eruption in Halema‘uma‘u Crater that began in March 2008 is the longest summit eruption of Kīlauea Volcano, on the Island of Hawai‘i, since 1924. From the time the eruption began, the new "Overlook crater" inside Halema‘uma‘u has exhibited fluctuating lava lake activity, occasional small explosive events, and a persistent gas plume. The beautiful nighttime glow impresses and thrills visitors in Hawai‘i Volcanoes National Park, but the continuous emission of sulfur dioxide gas produces "vog" (volcanic smog) that can severely affect communities and local agriculture downwind. U.S. Geological Survey scientists continue to closely monitor the eruption and assess ongoing hazards.
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Earth Observations taken by the Expedition 18 Crew
2008-12-03
ISS018-E-010206 (3 Dec. 2008) --- Mount Nemrut in Turkey is featured in this image photographed by an Expedition 18 crewmember on the International Space Station. This detailed view centers on the summit caldera of Mount Nemrut (Nemrut Dagi in Turkish), a stratovolcano located in the eastern Anatolia region of Turkey along the shoreline of Lake Van. Winter snow blankets the 2,948 meter elevation summit of the mountain, highlighting the brown caldera rim (a caldera is a large, usually circular or elliptical, collapse feature caused by the rapid emptying of an underlying magma chamber). The snow also highlights the irregular shape and wrinkled surfaces of several lava flows present in the eastern portion of the caldera. Lava flows associated with Mt. Nemrut range in composition from thin, fluid basalt to thick, glassy obsidian. A coldwater caldera lake occupies the western half of the summit. The geologic record at Mt. Nemrut indicates numerous prehistoric explosive eruptions during the Holocene Epoch ?which, according to scientists, began approximately 10,000 years ago and extends to the present day ? with eruption of lava last observed during 1441. The last well-documented explosive eruption occurred during 1650. Volcanism at Mt. Nemrut is the result of tectonic activity associated with the collision of the Arabian and Eurasian Plates; this collision is ongoing, and the presence of a warm water lake in the caldera suggests that the volcano is merely quiescent at present.
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Schmitt, Axel K.; Danišík, Martin; Aydar, Erkan; Şen, Erdal; Ulusoy, İnan; Lovera, Oscar M.
2014-01-01
A mural excavated at the Neolithic Çatalhöyük site (Central Anatolia, Turkey) has been interpreted as the oldest known map. Dating to ∼6600 BCE, it putatively depicts an explosive summit eruption of the Hasan Dağı twin-peaks volcano located ∼130 km northeast of Çatalhöyük, and a birds-eye view of a town plan in the foreground. This interpretation, however, has remained controversial not least because independent evidence for a contemporaneous explosive volcanic eruption of Hasan Dağı has been lacking. Here, we document the presence of andesitic pumice veneer on the summit of Hasan Dağı, which we dated using (U-Th)/He zircon geochronology. The (U-Th)/He zircon eruption age of 8.97±0.64 ka (or 6960±640 BCE; uncertainties 2σ) overlaps closely with 14C ages for cultural strata at Çatalhöyük, including level VII containing the “map” mural. A second pumice sample from a surficial deposit near the base of Hasan Dağı records an older explosive eruption at 28.9±1.5 ka. U-Th zircon crystallization ages in both samples range from near-eruption to secular equilibrium (>380 ka). Collectively, our results reveal protracted intrusive activity at Hasan Dağı punctuated by explosive venting, and provide the first radiometric ages for a Holocene explosive eruption which was most likely witnessed by humans in the area. Geologic and geochronologic lines of evidence thus support previous interpretations that residents of Çatalhöyük artistically represented an explosive eruption of Hasan Dağı volcano. The magmatic longevity recorded by quasi-continuous zircon crystallization coupled with new evidence for late-Pleistocene and Holocene explosive eruptions implicates Hasan Dağı as a potential volcanic hazard. PMID:24416270
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A sight "fearfully grand": eruptions of Lassen Peak, California, 1914 to 1917
Clynne, Michael A.; Christiansen, Robert L.; Stauffer, Peter H.; Hendley, James W.; Bleick, Heather A.
2014-01-01
On May 22, 1915, a large explosive eruption at the summit of Lassen Peak, California, the southernmost active volcano in the Cascade Range, devastated nearby areas and rained volcanic ash as far away as 280 miles to the east. This explosion was the most powerful in a series of eruptions during 1914–17 that were the last to occur in the Cascade Range before the 1980 eruption of Mount St. Helens, Washington. A century after the Lassen eruptions, work by U.S. Geological Survey (USGS) scientists in cooperation with the National Park Service is shedding new light on these events.
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Energetic Trend in Explosive Activity of Stromboli
NASA Astrophysics Data System (ADS)
Coltelli, M.; Cristaldi, A.; Mangiagli, S.; Nunnari, G.; Pecora, E.
2003-12-01
The typical activity of Stromboli consists of intermittent mild explosions lasting a few seconds, which take place at different vents and at variable intervals, the most common time interval being 10-20 minutes. However, the routine activity can be interrupted by more violent, paroxysmal explosions, that eject m-sized scoriaceous bombs and lava blocks to a distance of several hundreds of meters from the craters, endangering the numerous tourists that watch the spectacular activity from the volcano's summit located about two hundreds meters from the active vents. On average, 1-2 paroxysmal explosions occurred per year over the past century, but this statistic may be underestimated in absence of continuous monitoring. For this reason from summer 1996 a remote surveillance camera works on Stromboli recording continuously the volcanic activity. It is located on Pizzo Sopra la Fossa, 100 metres above the crater terrace where are the active vents. Using image analysis we seeks to identify any change of the explosive activity trend that could precede a particular eruptive event, like paroxysmal explosions, fire fountains, lava flows. The analysis include the counting of the explosions occurred at the different craters and the parameterization in classes of intensity for each explosion on the base of tephra dispersion and kinetics energy. Associating at each class a corresponding Index of energy in order to compute an heuristic value of the Average Daily Energy Released (ADER) of the explosive activity at Stromboli and plotting this value for each crater versus time, the diagram shows a cyclic behavior with max and min of explosive activity ranging from a few days to a month. Often the craters show opposite trends so when the activity decreases in a crater, increases in the other. Before every paroxysmal explosions recorded, the crater that produced the event decreased and then stopped its activity from a few days to weeks before. The other crater tried to compensate increasing its activity and when it declined the paroxysmal explosion occurred suddenly at the former site. From September 2001 an on-line image analyzer called VAMOS (Volcanic Activity MOnitoring System) operates detection and classification of explosive events in real-time. The system has automatically recorded and analyzed the change in the energetic trend that preceded the 20 October 2001 paroxysmal explosion that killed a woman and the strong explosive activity that preceded the onset of 28 December 2002 lava flow eruption.
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Persistent explosive activity at Stromboli investigated with OP-FTIR and SO2 cameras
NASA Astrophysics Data System (ADS)
Burton, M. R.; La Spina, A.; Sawyer, G. M.; Harris, A. J.
2012-12-01
Stromboli volcano in Italy exhibits what is perhaps one of the most well-known examples of cyclic activity, in the form of its regular explosions, which send a few m3 of material 100-200 m into the air every 10-20 minutes. Recent developments in measurements of volatile release from Stromboli using a series of novel approaches have allowed this cyclic behaviour to be examined in detail. In particular, the use of an automated OP-FTIR has revealed unprecedented detail in the dynamics of degassing from individual craters at the summit of Stromboli. Furthermore, the variations in composition of explosive degassing from Stromboli demonstrate a deep source ~2 km for the gas slugs which produce explosions at this volcano, in contrast to the commonly-held view that gas coalescence at shallow depth is responsible for the behaviour. The SO2 camera has revealed fascinating new details on the dynamics of degassing at Stromboli, and has allowed direct quantification of the amount of gas released during explosions and through quiescent degassing. The remarkable observation that 99% of degassing takes place quiescently, and that the explosions, whilst apparently more significant, are in fact a secondary process compared with the mass and energy involved in background, quiet processes. The new insight that the explosions are actually only a relatively minor aspect of the activity (in terms of mass and energy) actually makes the regularity of the cyclic explosive activity still more remarkable. In this paper we present a detailed overview of the state of the art of our understanding of cyclic explosive activity at Stromboli volcano from the perspective of recent advances in geochemical monitoring of the gas emissions. We also report initial results from a multidisciplinary campaign on Stromboli which utilised both OP-FTIR and SO2 camera techniques.
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NASA Astrophysics Data System (ADS)
Battaglia, J.; Hidalgo, S.; Douchain, J. M.; Pacheco, D. A.; Cordova, J.; Alvarado, A. P.; Parra, R.
2017-12-01
Tungurahua (5023 m a.s.l.) is an andesitic volcano located in Central Ecuador. It has been erupting since September 1999. It's activity transitioned in late 2008 towards the occurrence of distinct eruptive phases separated by periods of quiescence. These phases display a great variability of eruptive patterns. In particular the onsets of these phases are quite variable, ranging from progressive increase of surface activity to violent paroxysmal explosions eventually generating pyroclastic flows and plumes up to 13.000 m elevation. The volcano is monitored by the Instituto Geofisico in Quito whose permanent monitoring network include 6 broadband and 6 short period stations. These instruments record various signals related to eruptive processes as well as Long Period and volcano-tectonique (VT) events. However, most of the VT events are scattered around the volcano at depths up to 5-10 km b.s.l.. Their relationship with eruptive activity and precursory aspect are unclear. Since October 2013, we operate a temporary network of 13 broadband stations located up to 4275 m a.s.l., including on the Eastern flank which is remote. We examined data from a reference station located near the summit (3900 m a.s.l.) with a detection and classification procedure, searching for families of similar events. This processing enlights the presence of several families of small VTs previously poorly identified. We located manually some of these events and proceeded with similarity picking using cross-correlation and waveform similarity for nearly 400 events. Finally we applied precise relocation techniques. These events are located 2-3 km below the summit and define vertically elongated streaks. Their temporal evolution shows that they occur in swarms during the days or hours preceding the paroxysmal vent opening explosions in February and April 2014. These short-term precursors could indicate the rupturing of a barrier prior to the large explosions of Tungurahua.
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NASA Astrophysics Data System (ADS)
Somoza, L.; González, F. J.; Barker, S. J.; Madureira, P.; Medialdea, T.; de Ignacio, C.; Lourenço, N.; León, R.; Vázquez, J. T.; Palomino, D.
2017-08-01
Submarine volcanic eruptions are frequent and important events, yet they are rarely observed. Here we relate bathymetric and hydroacoustic images from the 2011 to 2012 El Hierro eruption with surface observations and deposits imaged and sampled by ROV. As a result of the shallow submarine eruption, a new volcano named Tagoro grew from 375 to 89 m depth. The eruption consisted of two main phases of edifice construction intercalated with collapse events. Hydroacoustic images show that the eruptions ranged from explosive to effusive with variable plume types and resulting deposits, even over short time intervals. At the base of the edifice, ROV observations show large accumulations of lava balloons changing in size and type downslope, coinciding with the area where floating lava balloon fallout was observed. Peaks in eruption intensity during explosive phases generated vigorous bubbling at the surface, extensive ash, vesicular lapilli and formed high-density currents, which together with periods of edifice gravitational collapse, produced extensive deep volcaniclastic aprons. Secondary cones developed in the last stages and show evidence for effusive activity with lava ponds and lava flows that cover deposits of stacked lava balloons. Chaotic masses of heterometric boulders around the summit of the principal cone are related to progressive sealing of the vent with decreasing or variable magma supply. Hornitos represent the final eruptive activity with hydrothermal alteration and bacterial mats at the summit. Our study documents the distinct evolution of a submarine volcano and highlights the range of deposit types that may form and be rapidly destroyed in such eruptions.
Plain Language SummaryToday and through most of geological history, the greatest number and volume of volcanic eruptions on Earth have occurred underwater. However, in comparison to subaerial eruption, little is known about submarine eruptive processes as they are dangerous to cruise it over, especially during explosive phases. This work shows the results of a study carried out during the eruption of the submarine volcano occurred during 2011-2012 1 km offshore El Hierro Island, Canary Islands, Spain. The submarine volcano emitted periodically large bubbles of gas, ashes, and giant steamed lava balloons that floated in the sea surface before sinking. These products identified later after the eruption using a submersible vehicle forming huge accumulations of lava balloons on the seafloor. More quiet periods erupted toothpaste lava from secondary cones which formed stalactite-like formations. Massive accumulation of blocks on the summit evidence intermittent violent explosions occurred when the cooling of lava progressively close the vent accumulating gas that finally exploded. The final stage of this submarine eruption consisted in the formation of chimneys by liquid-like lavas mixed with hydrothermal fluids forming 5-10 m tall "hornitos" structures at the summit of the volcano at 89 m depth but without emerging as it was expected.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRB..120.6474C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRB..120.6474C"><span>Amplitude and recurrence time analysis of LP activity at Mount Etna, Italy</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cauchie, Léna; Saccorotti, Gilberto; Bean, Christopher J.</p> <p>2015-09-01</p> <p>The aim of this work is to improve our understanding of the long-period (LP) source mechanism at Mount Etna (Italy) through a statistical analysis of detailed LP catalogues. The behavior of LP activity is compared with the empirical laws governing earthquake recurrence, in order to investigate whether any relationships exist between these two apparently different earthquake classes. We analyzed a family of 8894 events detected during a temporary experiment in August 2005. For that time interval, the LP activity is sustained in time and the volcano did not exhibit any evident sign of unrest. The completeness threshold of the catalogue is established through a detection test based on synthetic waveforms. The retrieved amplitude distribution differs significantly from the Gutenberg-Richter law, and the interevent times distribution does not follow the typical γ law, expected for tectonic activity. In order to compare these results with a catalogue for which the source mechanism is well established, we applied the same procedure to a data set from Stromboli Volcano, where recurrent LP activity is closely related to very-long-period pulses, in turn associated with the summit explosions. Our results indicate that the two catalogues exhibit similar behavior in terms of amplitude and interevent time distributions. This suggests that the Etna's LP signals are most likely driven by stress changes caused by an intermittent degassing process occurring at depth, similar to that which drives the summit explosions at Stromboli Volcano.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23575672','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23575672"><span>Seismic detection of increased degassing before Kīlauea's 2008 summit explosion.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Johnson, Jessica H; Poland, Michael P</p> <p>2013-01-01</p> <p>The 2008 explosion that started a new eruption at the summit of Kīlauea Volcano, Hawai'i, was not preceded by a dramatic increase in earthquakes nor inflation, but was associated with increases in SO2 emissions and seismic tremor. Here we perform shear wave splitting analysis on local earthquakes spanning the onset of the eruption. Shear wave splitting measures seismic anisotropy and is traditionally used to infer changes in crustal stress over time. We show that shear wave splitting may also vary due to changes in volcanic degassing. The orientation of fast shear waves at Kīlauea is usually controlled by structure, but in 2008 showed changes with increased SO2 emissions preceding the start of the summit eruption. This interpretation for changing anisotropy is supported by corresponding decreases in Vp/Vs ratio. Our result demonstrates a novel method for detecting changes in gas flux using seismic observations and provides a new tool for monitoring under-instrumented volcanoes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70047755','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70047755"><span>Seismic detection of increased degassing before Kīlauea's 2008 summit explosion</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Johnson, Jessica H.; Poland, Michael P.</p> <p>2013-01-01</p> <p>The 2008 explosion that started a new eruption at the summit of Kīlauea Volcano, Hawai‘i, was not preceded by a dramatic increase in earthquakes nor inflation, but was associated with increases in SO2 emissions and seismic tremor. Here we perform shear wave splitting analysis on local earthquakes spanning the onset of the eruption. Shear wave splitting measures seismic anisotropy and is traditionally used to infer changes in crustal stress over time. We show that shear wave splitting may also vary due to changes in volcanic degassing. The orientation of fast shear waves at Kīlauea is usually controlled by structure, but in 2008 showed changes with increased SO2 emissions preceding the start of the summit eruption. This interpretation for changing anisotropy is supported by corresponding decreases in Vp/Vs ratio. Our result demonstrates a novel method for detecting changes in gas flux using seismic observations and provides a new tool for monitoring under-instrumented volcanoes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss038e012569.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss038e012569.html"><span>Earth observations taken by Expedition 38 crewmember</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2013-12-06</p> <p>ISS038-E-012569 (6 Dec. 2013) --- Sollipulli Caldera is featured in this image photographed by an Expedition 38 crew member on the International Space Station. While active volcanoes are obvious targets of interest from the standpoint of natural hazards, there are some dormant volcanoes that nevertheless warrant concern due to their geologic history of activity. One such volcano is Sollipulli, located in central Chile near the border with Argentina in the southern Andes Mountains of South America. The volcano is located within the Parque Nacional Villarica of Chile. This photograph highlights the summit (2,282 meters above sea level) of the volcano and the bare slopes above the tree line. Lower elevations are covered with the green forests indicative of Southern Hemisphere summer. The summit of the volcano is occupied by a four-kilometer-wide caldera, currently filled with a snow-covered glacier (center). While most calderas form following violent explosive eruptions, the types of volcanic rock and deposits associated with such an event have not been found at Sollipulli. The geologic evidence does indicate explosive activity 2,900 years before present, and production of lava flows approximately 700 years before present. Together with craters and scoria cones located along the outer flanks of the caldera, scientists say this history suggests that Sollipulli could experience violent eruptions again, presenting an immediate potential hazard to such towns as Melipeuco in addition to the greater region.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA.....6590C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA.....6590C"><span>On-line image analysis of the stromboli volcanic activity recorded by the surveillance camera helps the forecasting of the major eruptive events.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cristaldi, A.; Coltelli, M.; Mangiagli, S.; Pecora, E.</p> <p>2003-04-01</p> <p>The typical activity of Stromboli consists of intermittent mild explosions lasting a few seconds, which take place at different vents and at variable intervals, the most common time interval being 10-20 minutes. However, the routine activity can be interrupted by more violent, paroxysmal explosions, that eject m-sized scoriaceous bombs and lava blocks to a distance of several hundreds of meters from the craters, endangering the numerous tourists that watch the spectacular activity from the volcano's summit located about two hundreds meters from the active vents. On average, 1-2 paroxysmal explosions occurred per year over the past century, but this statistic may be underestimated in absence of continuous monitoring. For this reason from summer 1996 a remote surveillance camera works on Stromboli recording continuously the volcanic activity. It is located on Pizzo Sopra la Fossa, 100 metres above the crater terrace where are the active vents. Using image analysis we seeks to identify any change of the explosive activity trend that could precede a particular eruptive event, like paroxysmal explosions, fire fountains, lava flows. From the day of the camera installation up to present 12 paroxysmal events and lava flows occurred. The analysis include the counting of the explosions occurred at the different craters and the parameterization in classes of intensity for each explosion on the base of tephra dispersion and kinetics energy. The plot of dissipated energy by each crater versus time shows a cyclic behavior with max and min of explosive activity ranging from a few days to a month. Often the craters show opposite trends so when the activity decreases in a crater, increases in the other. Before every paroxysmal explosions recorded, the crater that produced the event decreased and then stopped its activity from a few days to weeks before. The other crater tried to compensate increasing its activity and when it declined the paroxysmal explosion occurred suddenly at the former site. From September 2001 an on-line image analyzer called VAMOS (Volcanic Activity MOnitoring System) operates detection and classification of explosive events in quasi real-time. The system has automatically recorded and analyzed the change in the energetic trend that preceded the 20 October 2001 paroxysmal explosion that killed a woman and the strong explosive activity that preceded the onset of 28 December 2002 lava flow eruption.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRB..122.1558S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRB..122.1558S"><span>A decade of volcanic construction and destruction at the summit of NW Rota-1 seamount: 2004-2014</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schnur, Susan R.; Chadwick, William W.; Embley, Robert W.; Ferrini, Vicki L.; de Ronde, Cornel E. J.; Cashman, Katharine V.; Deardorff, Nicholas D.; Merle, Susan G.; Dziak, Robert P.; Haxel, Joe H.; Matsumoto, Haru</p> <p>2017-03-01</p> <p>Arc volcanoes are important to our understanding of submarine volcanism because at some sites frequent eruptions cause them to grow and collapse on human timescales. This makes it possible to document volcanic processes. Active submarine eruptions have been observed at the summit of NW Rota-1 in the Mariana Arc. We use remotely operated vehicle videography and repeat high-resolution bathymetric surveys to construct geologic maps of the summit of NW Rota-1 in 2009 and 2010 and relate them to the geologic evolution of the summit area over a 10 year period (2004-2014). We find that 2009 and 2010 were characterized by different eruptive styles, which affected the type and distribution of eruptive deposits at the summit. Year 2009 was characterized by ultraslow extrusion and autobrecciation of lava at a single eruptive vent, producing a large cone of blocky lava debris. In 2010, higher-energy explosive eruptions occurred at multiple closely spaced vents, producing a thin blanket of pebble-sized tephra overlying lava flow outcrops. A landslide that occurred between 2009 and 2010 had a major effect on lithofacies distribution by removing the debris cone and other unconsolidated deposits, revealing steep massive flow cliffs. This relatively rapid alternation between construction and destruction forms one end of a seamount growth and mass wasting spectrum. Intraplate seamounts, which tend to grow larger than arc volcanoes, experience collapse events that are orders of magnitude larger and much less frequent than those occurring at subduction zone settings. Our results highlight the interrelated cyclicity of eruptive activity and mass wasting at submarine arc volcanoes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JVGR..261..153B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JVGR..261..153B"><span>Analysis of the seismic activity associated with the 2010 eruption of Merapi Volcano, Java</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Budi-Santoso, Agus; Lesage, Philippe; Dwiyono, Sapari; Sumarti, Sri; Subandriyo; Surono; Jousset, Philippe; Metaxian, Jean-Philippe</p> <p>2013-07-01</p> <p>The 2010 eruption of Merapi is the first large explosive eruption of the volcano that has been instrumentally observed. The main characteristics of the seismic activity during the pre-eruptive period and the crisis are presented and interpreted in this paper. The first seismic precursors were a series of four shallow swarms during the period between 12 and 4 months before the eruption. These swarms are interpreted as the result of perturbations of the hydrothermal system by increasing heat flow. Shorter-term and more continuous precursory seismic activity started about 6 weeks before the initial explosion on 26 October 2010. During this period, the rate of seismicity increased almost constantly yielding a cumulative seismic energy release for volcano-tectonic (VT) and multiphase events (MP) of 7.5 × 1010 J. This value is 3 times the maximum energy release preceding previous effusive eruptions of Merapi. The high level reached and the accelerated behavior of both the deformation of the summit and the seismic activity are distinct features of the 2010 eruption. The hypocenters of VT events in 2010 occur in two clusters at of 2.5 to 5 km and less than 1.5 km depths below the summit. An aseismic zone was detected at 1.5-2.5 km depth, consistent with studies of previous eruptions, and indicating that this is a robust feature of Merapi's subsurface structure. Our analysis suggests that the aseismic zone is a poorly consolidated layer of altered material within the volcano. Deep VT events occurred mainly before 17 October 2010; subsequent to that time shallow activity strongly increased. The deep seismic activity is interpreted as associated with the enlargement of a narrow conduit by an unusually large volume of rapidly ascending magma. The shallow seismicity is interpreted as recording the final magma ascent and the rupture of a summit-dome plug, which triggered the eruption on 26 October 2010. Hindsight forecasting of the occurrence time of the eruption is performed by applying the Material Failure Forecast Method (FFM) using cumulative Real-time Seismic Amplitude (RSAM) calculated both from raw records and on signals classified according to their dominant frequency. Stable estimates of eruption time with errors as small as ± 4 h are obtained within a 6 day lapse time before the eruption. This approach could therefore be useful to support decision making in the case of future large explosive episodes at Merapi.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.V11B2027C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.V11B2027C"><span>Real-time radon monitoring at Stromboli volcano: influence of environmental parameters on 222Rn degassing</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cigolini, C.; Ripepe, M.; Poggi, P.; Laiolo, M.</p> <p>2008-12-01</p> <p>Two real-time stations for radon monitoring are currently operative at Stromboli volcano. The 222Rn electronic dosimeters are interfaced with an electronic board connected to a radiomodem for wireless data transfer (through a directional antenna) to a receiving station at the volcano observatory (COA). Radon activity data and enviromental parameters (soil temperature and atmospheric pressure) are sampled every 15 minutes and are instantaneously elaborated and transferred via web so that they can be checked in remote. Collected time series show that there is an overall inverse correlation between radon emissions and seasonal temperature variations. Signal processing analysis show that radon emissions in sectors of diffuse degassing are modulated by tidal forces as well. In addition, radon activities recorded at the summit station, located along the summit fracture zone where the gas flux is concentrated, are positively correlated with changes in atmospheric pressure and confirm the occurrence of the 'atmospheric stack effect'. It is not excluded that this process may play an active role in modulating Stromboli explosivity.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-sts077-715-037.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-sts077-715-037.html"><span>Earth observations taken during STS-77 mission</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>1996-05-28</p> <p>STS077-715-037 (19-29 May 1996) --- According to NASA scientists, Ruapehu, on New Zealand?s North Island, is one of the most active volcanoes in the South Pacific. Prior to the flight, crew members scheduled this site as one of their photographic targets. The volcano endured a significant eruption in late September, 1995. This view is the first image of the crater region since that eruption. Since then, numerous landslides and secondary explosions in the summit area has produced changes. In this view, recent mudflows extend from the summit region and down the mountain flank which is in the shadow. Ruapehu is also one of New Zealand?s high points - the mountain supports a glacier and permanent ice fields, and volcanic activity necessarily involves mixing hot volcanic products with snow and ice. Recent activity has produced destructive lahars (mudslides which are slurries of volcanic material with ice and water) downslope. A hazard warning to skiers is still in effect.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.V41B2790B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.V41B2790B"><span>Volcaniclastic stratigraphy of Gede volcano in West Java</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Belousov, A.; Belousova, M.; Zaennudin, A.; Prambada, O.</p> <p>2012-12-01</p> <p>Gede volcano (2958 m a.s.l.) and the adjacent Pangrango volcano (3019 m a.s.l.) form large (base diameter 35 km) volcanic massif 60 km south of Jakarta. While Pangrango has no recorded eruptions, Gede is one of the most active volcanoes in Indonesia: eruptions were reported 26 times starting from 1747 (Petroeschevsky 1943; van Bemmelen 1949). Historic eruptions were mildly explosive (Vulcanian) with at least one lava flow. Modern activity of the volcano includes persistent solfataric activity in the summit crater and periodic seismic swarms - in 1990, 1991, 1992, 1995, 1996, 1997, 2000, 2010, and 2012 (CVGHM). Lands around the Gede-Pangrango massif are densely populated with villages up to 1500-2000 m a.s.l. Higher, the volcano is covered by rain forest of the Gede-Pangrango Natural Park, which is visited every day by numerous tourists who camp in the summit area. We report the results of the detailed reinvestigation of volcaniclastic stratigraphy of Gede volcano. This work has allowed us to obtain 24 new radiocarbon dates for the area. As a result the timing and character of activity of Gede in Holocene has been revealed. The edifice of Gede volcano consists of main stratocone (Gumuruh) with 1.8 km-wide summit caldera; intra-caldera lava cone (Gede proper) with a 900 m wide summit crater, having 2 breaches toward N-NE; and intra-crater infill (lava dome/flow capped with 3 small craters surrounded by pyroclastic aprons). The Gumuruh edifice, composed mostly of lava flows, comprises more than 90% of the total volume of the volcano. Deep weathering of rocks and thick (2-4 m) red laterite soil covering Gumuruh indicates its very old age. Attempts to get 14C dates in 4 different locations of Gumuruh (including a large debris avalanche deposit on its SE foot) provided ages older than 45,000 years - beyond the limit for 14C dating. Outside the summit caldera, notable volumes of fresh, 14C datable volcaniclastic deposits were found only in the NNE sector of the volcano where they form a fan below the breached summit crater. The fan is composed of pyroclastic flows (PFs) and lahars of Holocene age that were deposited in 4 major stages: ~ 10 000 BP - voluminous PF of black scoria; ~ 4000 BP - two PFs of mingled grey/black scoria; ~ 1200 BP - multiple voluminous PFs strongly enriched by accidental material; ~ 1000 BP - a small scale debris avalanche (breaching of the crater wall) followed by small scale PFs of black scoria. The intra-crater lava dome/flow was erupted in 1840 (Petroeschevsky, 1943). Three small craters on the top of the lava dome were formed by multiple post-1840 small-scale phreatomagmatic eruptions. Ejected pyroclasts are lithic hydrothermally altered material containing a few breadcrust bombs. The Holocene eruptive history of Gede indicates that the volcano can produce moderately strong (VEI 3-4) explosive eruptions and send PFs and lahars onto the NE foot of the volcano.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li class="active"><span>2</span></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_2 --> <div id="page_3" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="41"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/of/1998/0106/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/1998/0106/report.pdf"><span>Preliminary volcano-hazard assessment for Augustine Volcano, Alaska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Waythomas, Christopher F.; Waitt, Richard B.</p> <p>1998-01-01</p> <p>Augustine Volcano is a 1250-meter high stratovolcano in southwestern Cook Inlet about 280 kilometers southwest of Anchorage and within about 300 kilometers of more than half of the population of Alaska. Explosive eruptions have occurred six times since the early 1800s (1812, 1883, 1935, 1964-65, 1976, and 1986). The 1976 and 1986 eruptions began with an initial series of vent-clearing explosions and high vertical plumes of volcanic ash followed by pyroclastic flows, surges, and lahars on the volcano flanks. Unlike some prehistoric eruptions, a summit edifice collapse and debris avalanche did not occur in 1812, 1935, 1964-65, 1976, or 1986. However, early in the 1883 eruption, a portion of the volcano summit broke loose forming a debris avalanche that flowed to the sea. The avalanche initiated a small tsunami reported on the Kenai Peninsula at English Bay, 90 kilometers east of the volcano. Plumes of volcanic ash are a major hazard to jet aircraft using Anchorage International and other local airports. Ashfall from future eruptions could disrupt oil and gas operations and shipping activities in Cook Inlet. Eruptions similar to the historical and prehistoric eruptions are likely in Augustine's future.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JVGR..351...75A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JVGR..351...75A"><span>Seismic monitoring of effusive-explosive activity and large lava dome collapses during 2013-2015 at Volcán de Colima, Mexico</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Arámbula-Mendoza, Raúl; Reyes-Dávila, Gabriel; Vargas-Bracamontes Dulce, M.; González-Amezcua, Miguel; Navarro-Ochoa, Carlos; Martínez-Fierros, Alejandro; Ramírez-Vázquez, Ariel</p> <p>2018-02-01</p> <p>Volcán de Colima, the most active volcano in Mexico, started a new eruptive cycle in January 2013. Since this date, the volcano has presented effusive and explosive activity. The beginning of the cycle was marked by a moderate Vulcanian explosion which had hyperbolical behavior in its precursory seismicity, possibly related to a shallow rupture process. Then, during the whole eruptive stage, the effusive activity was accompanied by low to moderate explosions. The explosions had energies mainly of 106 joules and were located between 0 and 1600 m below the crater, whereas the locations of tremor sources were found to be deeper, reaching up to 3800 m beneath the crater. Very-long-period signals (VLPs) have been observed with Vulcanian explosions that produce pyroclastic flows. A few number of volcano-tectonic events (VTs) were recognized during the studied period (2013-2015), indicating that the volcano is an open system. This was particularly evidenced in July 2015, when a new batch of magma rose rapidly without large precursors, only an accelerated increase in the number of rockfalls and associated RSEM. This event generated two large lava dome collapses with several pulses of material and pyroclastic flows that travelled up to 10.3 km from the summit. The seismic monitoring of Volcán de Colima is currently the only tool in real-time employed to assess the state of the volcanic activity. It is thus necessary to integrate new seismic methods as well as other geophysical monitoring techniques able to detect precursory signals of an impending hazardous event.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70113359','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70113359"><span>Explosive eruptions triggered by rockfalls at Kīlauea volcano, Hawaii</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Orr, Tim R.; Thelen, Weston A.; Patrick, Matthew R.; Swanson, Donald A.; Wilson, David C.</p> <p>2012-01-01</p> <p>Ongoing eruptive activity at Kīlauea volcano’s (Hawai‘i) summit has been controlled in part by the evolution of its vent from a 35-m-diameter opening into a collapse crater 150 m across. Geologic observations, in particular from a network of webcams, have provided an unprecedented look at collapse crater development, lava lake dynamics, and shallow outgassing processes. These observations show unequivocally that the hundreds of transient outgassing bursts and weak explosive eruptions that have punctuated the vent’s otherwise nearly steady-state behavior, and that are associated with composite seismic events, were triggered by rockfalls from the vent walls onto the top of the lava column. While the process by which rockfalls drive the explosive bursts is not fully understood, we believe that it is initiated by the generation of a rebound splash, or Worthington jet, which then undergoes fragmentation. The external triggering of low-energy outgassing events by rockfalls represents a new class of small transient explosive eruptions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA20239.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA20239.html"><span>Mt. Erebus, Antarctica</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2016-01-15</p> <p>This image from NASA Terra spacecraft shows Mount Erebus, the world southernmost historically active volcano, overlooking the McMurdo research station on Ross Island. The 3794-m-high Erebus is the largest of three major volcanoes forming the crudely triangular Ross Island. An elliptical 500 x 600 m wide, 110-m-deep crater truncates the summit and contains an active lava lake within a 250-m-wide, 100-m-deep inner crater. The glacier-covered volcano was erupting when first sighted by Captain James Ross in 1841. Continuous lava-lake activity with minor explosions, punctuated by occasional larger strombolian explosions that eject bombs onto the crater rim, has been documented since 1972, but has probably been occurring for much of the volcano's recent history. The image was acquired December 31, 2013, covers an area of 63 x 73 km, and is located at 77.5 degrees south, 167.1 degrees east. http://photojournal.jpl.nasa.gov/catalog/PIA20239</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.V53F..02S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.V53F..02S"><span>Intrusion Triggering of Explosive Eruptions: Lessons Learned from EYJAFJALLAJÖKULL 2010 Eruptions and Crustal Deformation Studies</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sigmundsson, F.; Hreinsdottir, S.; Hooper, A. J.; Arnadottir, T.; Pedersen, R.; Roberts, M. J.; Oskarsson, N.; Auriac, A.; Decriem, J.; Einarsson, P.; Geirsson, H.; Hensch, M.; Ofeigsson, B. G.; Sturkell, E. C.; Sveinbjornsson, H.; Feigl, K.</p> <p>2010-12-01</p> <p>Gradual inflation of magma chambers often precedes eruptions at highly active volcanoes. During eruptions, rapid deflation occurs as magma flows out and pressure is reduced. Less is known about the deformation style at moderately active volcanoes, such as Eyjafjallajökull, Iceland, where an explosive summit eruption of trachyandesite beginning on 14 April 2010 caused exceptional disruption to air traffic. This eruption was preceded by an effusive flank eruption of olivine basalt from 20 March - 12 April 2010. Geodetic and seismic observations revealed the growth of an intrusive complex in the roots of the volcano during three months prior to eruptions. After initial horizontal growth, modelling indicates both horizontal and sub-vertical growth in three weeks prior the first eruption. The behaviour is attributed to subsurface variations in crustal stress and strength originating from complicated volcano foundations. A low-density layer may capture magma allowing pressure to build before an intrusion can ascend towards higher levels. The intrusive complex was formed by olivine basalt as erupted on the volcano flank 20 March - 12 April; the intrusive growth halted at the onset of this eruption. Deformation associated with the eruption onset was minor as the dike had reached close to the surface in the days before. Isolated eruptive vents opening on long-dormant volcanoes may represent magma leaking upwards from extensive pre-eruptive intrusions formed at depth. A deflation source activated during the summit eruption of trachyandesite is distinct from, and adjacent to, all documented sources of inflation in the volcano roots. Olivine basalt magma which recharged the volcano appears to have triggered the summit eruption, although the exact mode of triggering is uncertain. Scenarios include stress triggering or propagation of olivine basalt into more evolved magma. The trachyandesite includes crystals that can be remnants of minor recent intrusion of olivine basalt. Alternatively, mixing of larger portion of olivine basalt with more evolved magma may have occurred. Intrusions may lead to eruptions not only when they find their way to the surface; at Eyjafjallajökull our observation show how primitive melts in an intrusive complex active since 1992 catalyzed an explosive eruption of trachyandesite. Eyjafjallajökull’s behaviour can be attributed to its off-rift setting with a relatively cold subsurface structure and limited magma at shallow depth, as may be typical for moderately active volcanoes. Clear signs of volcanic unrest signals over years to weeks may indicate reawakening of such volcanoes whereas immediate short-term precursors may be subtle and difficult to detect.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.V43A3138H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.V43A3138H"><span>Swarms of small earthquakes on Marapi Volcano, West Sumatra, Indonesia: are these precursors to explosion event?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hidayat, D.; Patria, C.; Adi, S.; Gunawan, H.; Taisne, B.; Nurfiani, D.; Tan, C. T.</p> <p>2016-12-01</p> <p>Marapi Volcano's activity is characterized by Strombolian to small Vulcanian explosions with occasional VEI 2 producing tephra and pyroclastic flows. Currently in collaboration between Earth Observatory of Singapore (EOS) and Centre for Volcanology and Geological Hazard Mitigation (CVGHM) the volcano is seismically monitored with 7 broadband stations, and 2 short-period stations. In addition, we deployed 2 tiltmeters and an experimental soil CO2 sensor. These stations are telemetered by 5.8GHz radio to Marapi Observatory Post where data are archived and displayed for Marapi observers for their daily volcano activity monitoring work. We also archive the data in the EOS and CVGHM main offices. Data are being utilized by volcano scientists of CVGHM and researchers in both institutes as well as university students in and around them. We presented seismic earthquake sequences (swarm) prior to small explosion on Marapi in July 2016. These earthquakes are small, better identified after the deployment of seismic stations at summit, and located at depths < 1km near the volcano active vents. Similar swarms occurred prior to small explosions of Marapi. We also presented VLP-LP signals associated with an explosion which can be explained as volumetric change of sub-vertical crack at depth similar to the occurrence of small earthquake swarms. Our study attempt to understand the state of the volcano based on monitoring data and enable us to better estimate the hazards associated with future small explosions or eruptions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70032583','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70032583"><span>Keanakākoʻi Tephra produced by 300 years of explosive eruptions following collapse of Kīlauea's caldera in about 1500 CE</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Swanson, Donald A.; Rose, Timothy R.; Fiske, Richard S.; McGeehin, John P.</p> <p>2012-01-01</p> <p>The Keanakākoʻi Tephra at Kīlauea Volcano has previously been interpreted by some as the product of a caldera-forming eruption in 1790 CE. Our study, however, finds stratigraphic and 14C evidence that the tephra instead results from numerous eruptions throughout a 300-year period between about 1500 and 1800. The stratigraphic evidence includes: (1) as many as six pure lithic ash beds interleaved in sand dunes made of earlier Keanakākoʻi vitric ash, (2) three lava flows from Kīlauea and Mauna Loa interbedded with the tephra, (3) buried syneruptive cultural structures, (4) numerous intraformational water-cut gullies, and (5) abundant organic layers rich in charcoal within the tephra section. Interpretation of 97 new accelerator mass spectrometry (AMS) 14C ages and 4 previous conventional ages suggests that explosive eruptions began in 1470–1510 CE, and that explosive activity continued episodically until the early 1800s, probably with two periods of quiescence lasting several decades. Kīlauea's caldera, rather than forming in 1790, predates the first eruption of the Keanakākoʻi and collapsed in 1470–1510, immediately following, and perhaps causing, the end of the 60-year-long, 4–6 km3 ʻAilāʻau eruption from the east side of Kīlauea's summit area. The caldera was several hundred meters deep when the Keanakākoʻi began erupting, consistent with oral tradition, and probably had a volume of 4–6 km3. The caldera formed by collapse, but no eruption of lava coincided with its formation. A large volume of magma may have quickly drained from the summit reservoir and intruded into the east rift zone, perhaps in response to a major south-flank slip event, leading to summit collapse. Alternatively, magma may have slowly drained from the reservoir during the prolonged ʻAilāʻau eruption, causing episodic collapses before the final, largest downdrop took place. Two prolonged periods of episodic explosive eruptions are known at Kīlauea, the Keanakākoʻi and the Uwēkahuna Tephra (Fiske et al., 2009), and both occurred when a deep caldera existed, probably with a floor at or below the water table, and external water could readily interact with the magmatic system. The next period of intense explosive activity will probably have to await the drastic deepening of the present caldera (or Halemaʻumaʻu Crater) or the formation of a new caldera.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70041461','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70041461"><span>Keanakākoʻi Tephra produced by 300 years of explosive eruptions following collapse of Kīlauea's caldera in about 1500 CE</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Swanson, Donald A.; Rose, Timothy R.; Fiske, Richard S.; McGeehin, John P.</p> <p>2012-01-01</p> <p>The Keanakākoʻi Tephra at Kīlauea Volcano has previously been interpreted by some as the product of a caldera-forming eruption in 1790 CE. Our study, however, finds stratigraphic and 14C evidence that the tephra instead results from numerous eruptions throughout a 300-year period between about 1500 and 1800. The stratigraphic evidence includes: (1) as many as six pure lithic ash beds interleaved in sand dunes made of earlier Keanakākoʻi vitric ash, (2) three lava flows from Kīlauea and Mauna Loa interbedded with the tephra, (3) buried syneruptive cultural structures, (4) numerous intraformational water-cut gullies, and (5) abundant organic layers rich in charcoal within the tephra section. Interpretation of 97 new accelerator mass spectrometry (AMS) 14C ages and 4 previous conventional ages suggests that explosive eruptions began in 1470–1510 CE, and that explosive activity continued episodically until the early 1800s, probably with two periods of quiescence lasting several decades. Kīlauea's caldera, rather than forming in 1790, predates the first eruption of the Keanakākoʻi and collapsed in 1470–1510, immediately following, and perhaps causing, the end of the 60-year-long, 4–6 km3 ʻAilāʻau eruption from the east side of Kīlauea's summit area. The caldera was several hundred meters deep when the Keanakākoʻi began erupting, consistent with oral tradition, and probably had a volume of 4–6 km3. The caldera formed by collapse, but no eruption of lava coincided with its formation. A large volume of magma may have quickly drained from the summit reservoir and intruded into the east rift zone, perhaps in response to a major south-flank slip event, leading to summit collapse. Alternatively, magma may have slowly drained from the reservoir during the prolonged ʻAilāʻau eruption, causing episodic collapses before the final, largest downdrop took place. Two prolonged periods of episodic explosive eruptions are known at Kīlauea, the Keanakākoʻi and the Uwēkahuna Tephra (Fiske et al., 2009), and both occurred when a deep caldera existed, probably with a floor at or below the water table, and external water could readily interact with the magmatic system. The next period of intense explosive activity will probably have to await the drastic deepening of the present caldera (or Halemaʻumaʻu Crater) or the formation of a new caldera.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002JVGR..117....1Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002JVGR..117....1Z"><span>Overview of the 1997 2000 activity of Volcán de Colima, México</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zobin, V. M.; Luhr, J. F.; Taran, Y. A.; Bretón, M.; Cortés, A.; De La Cruz-Reyna, S.; Domínguez, T.; Galindo, I.; Gavilanes, J. C.; Muñíz, J. J.; Navarro, C.; Ramírez, J. J.; Reyes, G. A.; Ursúa, M.; Velasco, J.; Alatorre, E.; Santiago, H.</p> <p>2002-09-01</p> <p>This overview of the 1997-2000 activity of Volcán de Colima is designed to serve as an introduction to the Special Issue and a summary of the detailed studies that follow. New andesitic block lava was first sighted from a helicopter on the morning of 20 November 1998, forming a rapidly growing dome in the summit crater. Numerous antecedents to the appearance of the dome were recognized, starting more than a year in advance, including: (1) pronounced increases in S/Cl and δD values at summit fumaroles in mid-1997; (2) five earthquake swarms between November-December 1997 and October-November 1998, with hypocenters that ranged down to 8 km beneath the summit and became shallower as the eruption approached; (3) steady inflation of the volcano reflected in shortening of geodetic survey line lengths beginning in November-December 1997 and continuing until the start of the eruption; (4) air-borne correlation spectrometer measurements of SO 2 that increased from the background values of <30 tons/day recorded since 1995 to reach 400 tons/day on 30 October 1998 and 1600 tons/day on 18 November 1998; and (5) small ash emissions detected by satellite-borne sensors beginning on 22 November 1997. The seismic and other trends were the basis of a short-term forecast of an eruption, announced on 13 November 1998, with a forecast window of 16-18 November. Although the lava dome actually appeared on 20 November, this forecast is considered to have been a major success, and the first of its kind at Volcán de Colima. Based in part on this forecast, orderly evacuations of Yerbabuena, Juan Barragan, and other small proximal communities took place on 18 November. The lava dome grew rapidly (˜4.4 m 3/s) on 20 November, and was spilling over the SW rim of the crater by the morning of 21 November to feed block-and-ash flows (pyroclastic flows) ahead of an advancing lobe of andesitic block lava. The pyroclastic flows were initially generated at intervals of 3-5 min, reached speeds of 80-90 km/h, and extended out to 4.5 km from the crater. The block lava flow was already ˜150 m long by the afternoon of 21 November. It ultimately split into three lobes that flowed down the three branches of Barranca el Cordobán on the SSW flank of Volcán de Colima; the lava advanced atop previously emplaced pyroclastic-flow deposits from the same eruptive event, whose total volume is estimated as 24×10 5 m 3. The three lava lobes ultimately reached 2.8-3.8 km from the crater, had flow fronts ˜30 m high, and an estimated total volume of 39×10 6 m 3. By early February 1999 the lava flows were no longer being fed from the summit crater, but the flow fronts continued their slow advance driven by gravitational draining of their partially molten interiors. The 1998-1999 andesites continued a compositional trend toward relatively higher SiO 2 and lower MgO that began with the 1991 lava eruption, completing the reversal of an excursion to more mafic compositions (lower SiO 2 and higher MgO) that occurred during 1976-1982. Accordingly, the 1998-1999 andesites show no signs of a transition toward the more mafic magmas that have characterized the major explosive eruptions of Volcán de Colima, such as those of 1818 and 1913. A large explosion on 10 February 1999 blasted a crater through the 1998-1999 lava dome and marked the beginning of a new explosive stage of activity at Volcán de Colima. Incandescent blocks showered the flanks out to 5 km distance, forming impact craters and triggering numerous forest fires. Similar large explosions occurred on 10 May and 17 July 1999, interspersed with numerous smaller explosions of white steam or darker ash-bearing steam. Intermittent minor explosive activity continued through the year 2000, and another large explosion took place on 22 February, 2001.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70041411','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70041411"><span>Detecting hidden volcanic explosions from Mt. Cleveland Volcano, Alaska with infrasound and ground-couples airwaves</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>De Angelis, Slivio; Fee, David; Haney, Matthew; Schneider, David</p> <p>2012-01-01</p> <p>In Alaska, where many active volcanoes exist without ground-based instrumentation, the use of techniques suitable for distant monitoring is pivotal. In this study we report regional-scale seismic and infrasound observations of volcanic activity at Mt. Cleveland between December 2011 and August 2012. During this period, twenty explosions were detected by infrasound sensors as far away as 1827 km from the active vent, and ground-coupled acoustic waves were recorded at seismic stations across the Aleutian Arc. Several events resulting from the explosive disruption of small lava domes within the summit crater were confirmed by analysis of satellite remote sensing data. However, many explosions eluded initial, automated, analyses of satellite data due to poor weather conditions. Infrasound and seismic monitoring provided effective means for detecting these hidden events. We present results from the implementation of automatic infrasound and seismo-acoustic eruption detection algorithms, and review the challenges of real-time volcano monitoring operations in remote regions. We also model acoustic propagation in the Northern Pacific, showing how tropospheric ducting effects allow infrasound to travel long distances across the Aleutian Arc. The successful results of our investigation provide motivation for expanded efforts in infrasound monitoring across the Aleutians and contributes to our knowledge of the number and style of vulcanian eruptions at Mt. Cleveland.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70179211','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70179211"><span>Local infrasound observations of large ash explosions at Augustine Volcano, Alaska, during January 11–28, 2006</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Petersen, Tanja; De Angelis, Silvio; Tytgat, Guy; McNutt, Stephen R.</p> <p>2006-01-01</p> <p>We present and interpret acoustic waveforms associated with a sequence of large explosion events that occurred during the initial stages of the 2006 eruption of Augustine Volcano, Alaska. During January 11–28, 2006, 13 large explosion events created ash-rich plumes that reached up to 14 km a.s.l., and generated atmospheric pressure waves that were recorded on scale by a microphone located at a distance of 3.2 km from the active vent. The variety of recorded waveforms included sharp N-shaped waves with durations of a few seconds, impulsive signals followed by complex codas, and extended signals with emergent character and durations up to minutes. Peak amplitudes varied between 14 and 105 Pa; inferred acoustic energies ranged between 2×108 and 4×109 J. A simple N-shaped short-duration signal recorded on January 11, 2006 was associated with the vent-opening blast that marked the beginning of the explosive eruption sequence. During the following days, waveforms with impulsive onsets and extended codas accompanied the eruptive activity, which was characterized by explosion events that generated large ash clouds and pyroclastic flows along the flanks of the volcano. Continuous acoustic waveforms that lacked a clear onset were more common during this period. On January 28, 2006, the occurrence of four large explosion events marked the end of this explosive eruption phase at Augustine Volcano. After a transitional period of about two days, characterized by many small discrete bursts, the eruption changed into a stage of more sustained and less explosive activity accompanied by the renewed growth of a summit lava dome.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70019495','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70019495"><span>Source and path effects in the wave fields of tremor and explosions at Stromboli Volcano, Italy</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Chouet, B.; Saccorotti, G.; Martini, M.; Dawson, P.; De Luca, G.; Milana, G.; Scarpa, R.</p> <p>1997-01-01</p> <p>The wave fields generated by Strombolian activity are investigated using data from small-aperture seismic arrays deployed on the north flank of Stromboli and data from seismic and pressure transducers set up near the summit crater. Measurements of slowness and azimuth as a function of time clearly indicate that the sources of tremor and explosions are located beneath the summit crater at depths shallower than 200 m with occasional bursts of energy originating from sources extending to a depth of 3 km. Slowness, azimuth, and particle motion measurements reveal a complex composition of body and surface waves associated with topography, structure, and source properties. Body waves originating at depths shallower than 200 m dominate the wave field at frequencies of 0.5-2.5 Hz, and surface waves generated by the surficial part of the source and by scattering sources distributed around the island dominate at frequencies above 2.5 Hz. The records of tremor and explosions are both dominated by SH motion. Far-field records from explosions start with radial motion, and near-field records from those events show dominantly horizontal motion and often start with a low-frequency (1-2 Hz) precursor characterized by elliptical particle motion, followed within a few seconds by a high-frequency radial phase (1-10 Hz) accompanying the eruption of pyroclastics. The dominant component of the near- and far-field particle motions from explosions, and the timing of air and body wave phases observed in the near field, are consistent with a gaspiston mechanism operating on a shallow (<200 m deep), vertical crack-like conduit. Models of a degassing fluid column suggest that noise emissions originating in the collective oscillations of bubbles ascending in the magma conduit may provide an adequate self-excitation mechanism for sustained tremor generation at Stromboli. Copyright 1997 by the American Geophysical Union.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70034648','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70034648"><span>Shallow degassing events as a trigger for very-long-period seismicity at Kīlauea Volcano, Hawai‘i</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Patrick, Matthew; Wilson, David; Fee, David; Orr, Tim R.; Swanson, Donald A.</p> <p>2011-01-01</p> <p>The first eruptive activity at Kīlauea Volcano’s summit in 25 years began in March 2008 with the opening of a 35-m-wide vent in Halema‘uma‘u crater. The new activity has produced prominent very-long-period (VLP) signals corresponding with two new behaviors: episodic tremor bursts and small explosive events, both of which represent degassing events from the top of the lava column. Previous work has shown that VLP seismicity has long been present at Kīlauea’s summit, and is sourced approximately 1 km below Halema‘uma‘u. By integrating video observations, infrasound and seismic data, we show that the onset of the large VLP signals occurs within several seconds of the onset of the degassing events. This timing indicates that the VLP is caused by forces—sourced at or very near the lava free surface due to degassing—transmitted down the magma column and coupling to the surrounding rock at 1 km depth.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17808499','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17808499"><span>Deformation studies on soufriere, st. Vincent, between 1977 and 1981.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fiske, R S; Shepherd, J B</p> <p>1982-06-04</p> <p>Dry-tilt measurements at two stations indicate that Soufriere Volcano gradually inflated at least 10 microradians prior to the initial explosions of April 1979 and then rapidly deflated more than 20 microradians after the activity got under way. The tilt measured at the station 6.5 kilometers from the summit was about twice that measured at a distance of 2.5 kilometers. This finding suggests the existence of a magma chamber at a depth of more than 10 kilometers.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009JVGR..184..367R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009JVGR..184..367R"><span>The 2005 eruption of Kliuchevskoi volcano: Chronology and processes derived from ASTER spaceborne and field-based data</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rose, Shellie; Ramsey, Michael</p> <p>2009-07-01</p> <p>Kliuchevskoi volcano, located on the Kamchatka peninsula of eastern Russia, is one of the largest and most active volcanoes in the world. Its location and diversity of eruption styles make satellite-based monitoring and characterization of its eruptive activity essential. In 2005, the Kamchatka Volcano Emergency Response Team (KVERT) first reported that seismic activity of Kliuchevskoi increased above background levels on 12 January (Kamchatka Volcanic Eruption Response Team (KVERT) Report, 2005. Kliuchevskoi Volcano, 14 January through 13 May 2005. ( http://www.avo.alaska.edu/activity/avoreport.php?view=kam info&id=&month=January&year=2005). Cited January 2007). By 15 January Kliuchevskoi entered an explosive-effusive phase, which lasted for five months and produced basaltic lava flows, lahar deposits, and phreatic explosions along its northwestern flank. We present a comparison between field observations and multispectral satellite image data acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument in order to characterize the eruptive behavior. The ASTER instrument was targeted in an automated urgent request mode throughout the eruption timeline in order to collect data at the highest observation frequency possible. Brightness temperatures were calculated in all three ASTER wavelength regions during lava flow emplacement. The maximum lava flow brightness temperatures, calculated from the 15 m/pixel visible near infrared (VNIR) data, were in excess of 800 °C. The shortwave infrared (SWIR) data were radiometrically and geometrically corrected, normalized to the same gain settings, and used to estimate an eruptive volume of 2.35 × 10 - 2 km 3 at the summit. These data were also used to better constrain errors arising in the thermal infrared (TIR) data due to sub-pixel thermal heterogeneities. Based on all the ASTER data, the eruption was separated into three phases: an initial explosive phase (20 January-31 January), an explosive-effusive phase (1 February-8 March), and a subsequent cooling phase. Decorrelation stretch (DCS) images of the TIR data also suggested the presence of silicate ash, SO 2, and water vapor plumes that extended up to 300 km from the summit. The ASTER rapid-response program provided important multispectral, moderate spatial resolution information that was used to detect and monitor the eruptive activity of this remote volcano which can be applied to other eruptions worldwide.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.S51B0596R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.S51B0596R"><span>Infrasound as a Long Standing Tool for Monitoring Continental Ecuadorean Volcanoes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ruiz, M. C.; Ortiz, H. D.; Hernandez, S.; Palacios, P.; Anzieta, J. C.</p> <p>2017-12-01</p> <p>In the last 10 years, infrasound and seismic methods have been successfully used in the continuous monitoring of eruptive activity at Tunguruhua, Reventador, Sangay and Cotopaxi volcanoes. After a dormant period of 81 years, Tungurahua woke up in 1999 and has since been characterized by vulcanian and strombolian eruptions. Beginning in July 2006, a permanent seismo-infrasonic network with 5 collocated seismic and infrasound sensors was installed through a cooperation with Japan International Cooperation Agency (JICA). It recorded more than 6,000 explosions at Tungurahua with reduced amplitudes larger than 270 Pa at 1 km from the active crater, including 3 explosions greater than 6000 Pa associated with short-lived explosions. Major and long sustained eruptions (July 14-15, 2006; August 16-17, 2006; February 6-8, 2008, May 28, 2010; December 4, 2010; December 3-4, 2011; August 18, 2012) generated seismic and infrasound tremors with complex waveforms. In 2002, Reventador volcano produced the largest eruption in Ecuador in the last century (VEI-4). Since September 2012, alternating periods of strombolian activity and short-lived vulcanian explosions are monitored by seismic and microbarometer sensors located on the south-east border of the caldera rim. Non-steady activity with fluctuations between quiescence and frequent explosions, tremor, and chugging events is recorded. Infrasound of explosions ranges from 75 to 6350 Pa in reduced peak-to-peak amplitudes. Sangay, a remote and very active volcano, is monitored by a broadband seismometer and microbarometer collocated at 8 km from the summit. Active periods during the last few months are characterized by explosion events followed by lava flows and small ash emissions. In March 2016, more than 100 explosions were recorded in a single day. Finally, in 2015 Cotopaxi volcano began its recent eruptive period after 138 years of quiescence. One month after the initiation of its eruptive activity, 76 harmonic infrasound signals with a characteristic 5 sec. period were recorded between September and December 2015 that have been related to outgassing or explosive bubble bursts that excite resonance modes in unfilled craters.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-sts064-71-037.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-sts064-71-037.html"><span>Mt. Etna, Sicily as seen from STS-64</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>1994-09-19</p> <p>STS064-71-037 (9-20 Sept. 1994) --- Mt. Etna on Sicily displays a steam plume from its summit. Geologists attribute the volcano's existence to the collision of tectonic plates. Unlike the sudden, explosive eruption at Rabaul, Mt. Etna's activity is ongoing and is generally not explosive - Etna's slopes have been settled with villages and cultivated land for centuries. Other Mediterranean volcanoes (like Santorini) have experienced large catastrophic eruptions. Etna recently finished a two-year eruption (ending in 1993), marked by relatively gentle lava flows down the eastern flank. It has been continually degassing since then, according to the geologists, producing an omnipresent steam plume, as seen here. The 1993 flow is difficult to identify in this image because it lies within shadows on the eastern flank, but small cinder cones on the western flank mark earlier episodes of volcanic activity. Photo credit: NASA or National Aeronautics and Space Administration</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.S51B0598D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.S51B0598D"><span>Assessment of eruption intensity using infrasound waveform inversion at Mt. Etna, Italy.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Diaz Moreno, A.; Iezzi, A. M.; Lamb, O. D.; Zuccarello, L.; Fee, D.; De Angelis, S.</p> <p>2017-12-01</p> <p>Mt. Etna, Italy, a 3,330 m stratovolcano, is one of the most active volcanoes in the world. It is topped by five craters: Voragine, Bocca Nuova, the North-East, South-East, and New South-East Crater. Its activity during the past decade can be separated into two main types: i) nearly-continuous degassing interspersed by mild-to-vigorous Strombolian activity within the summit craters, and ii) effusive flank eruptions. In June 2017, we deployed a large temporary network of 14 infrasound sensors (Chaparral UHP60) and 12 broadband seismometers (Guralp EX-120s). We also recorded Thermal Infrared (TIR) and Unmanned Aerial Vehicle images of activity at the summit vents. Our primary objective is to quantify the intensity and mechanisms of infrasound sources at Mt. Etna, and use these results to improve models of volcanic plumes. From June 2017 until the time of writing, the infrasound network detected signals associated with nearly-continuous degassing and discrete small-to-moderate explosions originating at two distinct locations within the Voragine Crater and the New South-East Crater, respectively. During periods of increased explosive activity, we recorded 20-30 discrete events/day with infrasonic amplitudes of up to 7.5 Pa at 1 km distance from the active vent. The explosions exhibited sinusoidal acoustic waveforms, often with similar characteristics, durations of 1-3 s, and a 2 Hz peak frequency. Due to the relatively dense station coverage and the azimuthal distribution of the network, our deployment offers an opportunity to characterize, with unprecedented resolution, infrasound sources at Mt. Etna. Here we present preliminary results of 3D acoustic wave-field simulations, using a Finite Difference Time Domain modelling scheme, and a preliminary assessment of volumetric eruption rates through acoustic waveform inversion. We investigate the effects of local topography and atmospheric winds on the propagation of the acoustic wavefield, and discuss the implications for infrasound-based assessments of eruption intensity. Our network will be deployed through August 2017, with the hopes of catching larger and more diverse eruptions as well.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss033e019822.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss033e019822.html"><span>Earth Observation taken by the Expedition 33 crew</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-11-09</p> <p>ISS033-E-019822 (9 Nov. 2012) --- An eruption plume from the Karymsky volcano on the Kamchatka Peninsula in the Russian Federation is visible in this image photographed by an Expedition 33 crew member on the International Space Station. The Karymsky stratovolcano stands 1,536 meters above sea level, with most eruptions and occasional lava flows originating from the summit. Karymsky is the most active of Kamchatka’s eastern volcanoes, with almost constant (on a geologic time scale) volcanism occurring since at least the late 18th century when the historical record for the region begins. In light of the high levels of volcanic activity on the Kamchatka Peninsula, the Kamchatka Volcanic Eruption Response Team (KVERT) monitors the activity levels of several volcanoes and issues updates including aviation alerts and webcams. KVERT reported moderate seismic activity at Karymsky during 2-9 Nov. 2012; such activity can indicate movement of magma beneath or within a volcanic structure and can indicate that an eruption is imminent. The Tokyo Volcanic Ash Advisory Center (VAAC) subsequently reported an explosive eruption at Karymsky on Nov. 9, 2012 at 22:15 GMT. This photograph of the resulting ash plume was taken approximately one hour and 35 minutes after the eruption began. The plume extends from the summit of Karymsky (bottom center) to the southeast, with brown ash deposits darkening the snow cover below the plume. The Akademia Nauk caldera – now filled with water to form the present-day Karymsky Lake - is located to the south of Karymsky volcano. Calderas are formed by explosive eruption and emptying of a volcano’s magma chamber – leading to collapse of the structure to form a large crater-like depression. Akademia Nauk last erupted in 1996.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.V31B3015H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.V31B3015H"><span>Seismic and deformation precursory to the small explosions of Marapi Volcano, West Sumatra, Indonesia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hidayat, D.; Patria, C.; Gunawan, H.; Taisne, B.; Nurfiani, D.; Avila, E. J.</p> <p>2015-12-01</p> <p>Marapi Volcano is one of the active volcanoes of Indonesia located near the city of Bukittinggi, West Sumatra, Indonesia. Its activity is characterized by small vulcanian explosions with occasional VEI 2 producing tephra and pyroclastic flows. Due to its activity, it is being monitored by Centre for Volcanology and Geological Hazard Mitigation (CVGHM). Four seismic stations consists of 2 broadband and 2 short period instruments have been established since 2009. In collaboration with CVGHM, Earth Observatory of Singapore added 5 seismic stations around the volcano in 2014, initially with short period instruments but later upgraded to broadbands. We added one tilt station at the summit of Marapi. These seismic and tilt stations are telemetered by 5.8GHz radio to Marapi Observatory Post where data are archived and displayed for Marapi observers for their daily volcanic activity monitoring work. We also archive the data in the EOS and CVGHM main offices. Here we are presenting examples of seismic and deformation data from Marapi prior, during, and after the vulcanian explosion. Our study attempt to understand the state of the volcano based on monitoring data and in order to enable us to better estimate the hazards associated with the future eruptions of this or similar volcano.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_3 --> <div id="page_4" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="61"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.V23C2851O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.V23C2851O"><span>Degassing system from the magma reservoir of Miyakejima volcano revealed by GPS observations</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oikawa, J.; Nakao, S.; Matsushima, T.</p> <p>2013-12-01</p> <p>Miyake-jima is a volcanic island located approximately 180 km south of Tokyo. The island is an active basaltic volcano that was dormant for a 17-year period between an eruption in 1983 and June 26, 2000, when it again became active. The volcanic activity that occurred in 2000 is divided into the following four stages: the magma intrusion stage, summit subsidence stage, summit eruptive stage, and degassing stage (Nakada et al., 2001). Earthquake swarm activity began on June 26, 2000, accompanied by large-scale crustal deformation. This led to a summit eruption on July 8, 2000. Based on the pattern of hypocenter migration and the nature of crustal deformation, it was estimated that magma migrated from beneath the summit of Miyake-jima to the northwest during the magma intrusion stage. The rapid collapse of the summit took place between July 8 and the beginning of August 2000 (summit subsidence stage). Large-scale eruptions took place on August 10, 18, and 29, 2000 (explosion stage). The eruptions largely ceased after August 29, followed by the release of large amounts of gas from the summit crater (degassing stage). In this study, we examined the location of the magma reservoir during the degassing stage based on crustal deformation observed by GPS. By comparing the amounts of degassing and volume change of the magma reservoir, as determined from crustal deformation, we determined the mechanism of degassing and the nature of the magma reservoir-vent system. According to observations by the Japan Meteorological Agency, a large amount of volcanic gas began to be released from Miyake-jima in September 2000 (Kazahaya et al., 2003). Approximately 42,000 tons/day of SO2 was released during the period between September 2000 and January 2001. Analysis of GPS data during the period [Figure 1] indicates a source of crustal deformation on the south side of the summit crater wall at a depth of 5.2 km. The rate of volume change was -3.8 x 106 m3/month [Figure 2]. As the volume is equivalent to the volume occupied by the volatile components such as SO2, H2O, CO2 dissolved in the magma, it is proposed that contraction of the magma reservoir reflects degassing of its volatile components. The observations indicate that the magma reservoir is connected to the summit crater by a magma-filled vent. Convection within the vent carries volatile-rich magma upward to the crater, where volcanic gas is released by degassing. The depleted magma is then carried into the magma reservoir, which contracts due to the loss of volume originally occupied by the volcanic gas. Figure 1 shows displacements per month. Vectors show the horizontal movements. Contours and shading indicate vertical displacement. Figure 2 shows theoretical displacement assuming the Mogi model.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/pp/p1615/p1615po.pdf#page=29','USGSPUBS'); return false;" href="https://pubs.usgs.gov/pp/p1615/p1615po.pdf#page=29"><span>Mount Mageik: A compound stratovolcano in Katmai National Park: A section in Geologic studies in Alaska by the U.S. Geological Survey, 1998</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hildreth, Wes; Fierstein, Judy; Lanphere, Marvin A.; Siems, David F.</p> <p>2000-01-01</p> <p>Mount Mageik is an ice-clad 2,165-m andesite-dacite stratovolcano in the Katmai volcanic cluster at the head of the Valley of Ten Thousand Smokes. New K-Ar ages indicate that the volcano is as old as 93±8 ka. It has a present-day volume of 20 km3 but an eruptive volume of about 30 km3, implying a longterm average volumetric eruption rate of about 0.33 km3 per 1,000 years. Mount Mageik consists of four overlapping edi- fices, each with its own central summit vent, lava-flow apron, and independent eruptive history. Three of them have small fragmental summit cones with ice-filled craters, but the fourth and highest is topped by a dacite dome. Lava flows predominate on each edifice; many flows have levees and ice-contact features, and many thicken downslope into piedmont lava lobes 50–200 m thick. Active lifetimes of two (or three) of the component edifices may have been brief, like that of their morphological and compositional analog just across Katmai Pass, the Southwest (New) Trident edifice of 1953–74. The North Summit edi- fice of Mageik may have been constructed very late in the Pleistocene and the East Summit edifice (along with nearby Mount Martin) largely or entirely in the Holocene. Substantial Holocene debris avalanches have broken loose from three sites on the south side of Mount Mageik, the youngest during the Novarupta fallout of 6 June 1912. The oldest one was especially mobile, being rich in hydrothermal clay, and is preserved for 16 km downvalley, probably having run out to the sea. Mageik's fumarolically active crater, which now contains a hot acid lake, was never a magmatic vent but was reamed by phreatic explosions through the edge of the dacite summit dome. There is no credible evidence of historical eruptions of Mount Mageik, but the historically persistent fumarolic plumes of Mageik and Martin have animated many spurious eruption reports. Lavas and ejecta of all four component edifices of Mageik are plagioclaserich, pyroxene-dacites and andesites (57–68 weight percent SiO2) that form a calcic, medium-K, typically low-Ti arc suite. The Southwest Summit edifice is larger, longer lived, and compositionally more complex than its companions. Compared to other centers in the Katmai cluster, products of Mount Mageik are readily distinguishable chemically from those of Mount Griggs, Falling Mountain, Mount Cerberus, and all prehistoric components of the Trident group, but some are similar to the products of Mount Martin, Southwest Trident, and Novarupta. The crater lake, vigorous superheated fumaroles, persistent seismicity, steep ice blanket, and numerous Holocene dacites warrant monitoring Mount Mageik as a potential source of explosive eruptions and derivative debris flows.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JVGR..344..197W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JVGR..344..197W"><span>Surface deformation induced by magmatic processes at Pacaya Volcano, Guatemala revealed by InSAR</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wnuk, K.; Wauthier, C.</p> <p>2017-09-01</p> <p>Pacaya Volcano, Guatemala is a continuously active, basaltic volcano with an unstable western flank. Despite continuous activity since 1961, a lack of high temporal resolution geodetic surveying has prevented detailed modeling of Pacaya's underlying magmatic plumbing system. A new, temporally dense dataset of Interferometric Synthetic Aperture Radar (InSAR) RADARSAT-2 images, spanning December 2012 to March 2014, show magmatic deformation before and during major eruptions in January and March 2014. Inversion of InSAR surface displacements using simple analytical forward models suggest that three magma bodies are responsible for the observed deformation: (1) a 4 km deep spherical reservoir located northwest of the summit, (2) a 0.4 km deep spherical source located directly west of the summit, and (3) a shallow dike below the summit. Periods of heightened volcanic activity are instigated by magma pulses at depth, resulting in rapid inflation of the edifice. We observe an intrusion cycle at Pacaya that consists of deflation of one or both magma reservoirs followed by dike intrusion. Intrusion volumes are proportional to reservoir volume loss and do not always result in an eruption. Periods of increased activity culminate with larger dike-fed eruptions. Large eruptions are followed by inter-eruptive periods marked by a decrease in crater explosions and a lack of detected deformation. Co-eruptive flank motion appears to have initiated a new stage of volcanic rifting at Pacaya defined by repeated NW-SE oriented dike intrusions. This creates a positive feedback relationship whereby magmatic forcing from eruptive dike intrusions induce flank motion.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2018/5008/sir20185008.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2018/5008/sir20185008.pdf"><span>Lava lake activity at the summit of Kīlauea Volcano in 2016</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Patrick, Matthew R.; Orr, Tim R.; Swanson, Donald A.; Elias, Tamar; Shiro, Brian</p> <p>2018-04-10</p> <p>The ongoing summit eruption at Kīlauea Volcano, Hawai‘i, began in March 2008 with the formation of the Overlook crater, within Halema‘uma‘u Crater. As of late 2016, the Overlook crater contained a large, persistently active lava lake (250 × 190 meters). The accessibility of the lake allows frequent direct observations, and a robust geophysical monitoring network closely tracks subtle changes at the summit. These conditions present one of the best opportunities worldwide for understanding persistent lava lake behavior and the geophysical signals associated with open-vent basaltic eruptions. In this report, we provide a descriptive and visual summary of lava lake activity during 2016, a year consisting of continuous lava lake activity. The lake surface was composed of large black crustal plates separated by narrow incandescent spreading zones. The dominant motion of the surface was normally from north to south, but spattering produced transient disruptions to this steady motion. Spattering in the lake was common, consisting of one or more sites on the lake margin. The Overlook crater was continuously modified by the deposition of spatter (often as a thin veneer) on the crater walls, with frequent collapses of this adhered lava into the lake. Larger collapses, involving lithic material from the crater walls, triggered several small explosive events that deposited bombs and lapilli around the Halema‘uma‘u Crater rim, but these did not threaten public areas. The lava lake level varied over several tens of meters, controlled primarily by changes in summit magma reservoir pressure (in part driven by magma supply rates) and secondarily by fluctuations in spattering and gas release from the lake (commonly involving gas pistoning). The lake emitted a persistent gas plume, normally averaging 1,000–8,000 metric tons per day (t/d) of sulfur dioxide (SO2), as well as a constant fallout of small juvenile and lithic particles, including Pele’s hair and tears. The gas emissions created volcanic air pollution (vog) that affected large areas of the Island of Hawai‘i. The summit eruption has been a major attraction for visitors in Hawai‘i Volcanoes National Park. During 2016, the rising lake levels allowed the lake and its spattering to be more consistently visible from public viewing areas, enhancing the visitor experience. The U.S. Geological Survey’s Hawaiian Volcano Observatory (HVO) closely monitors the summit eruption and keeps emergency managers and the public informed of activity.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2001/0457/pdf/of2001-0457.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2001/0457/pdf/of2001-0457.pdf"><span>Lahar Hazards at Concepción volcano, Nicaragua</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Vallance, J.W.; Schilling, S.P.; Devoli, G.; Howell, M.M.</p> <p>2001-01-01</p> <p>Concepción is one of Nicaragua’s highest and most active volcanoes. The symmetrical cone occupies the northeastern half of a dumbbell shaped island called Isla Ometepa. The dormant volcano, Maderas, occupies the southwest half of the island. A narrow isthmus connects Concepción and Maderas volcanoes. Concepción volcano towers more than 1600 m above Lake Nicaragua and is within 5 to 10 km of several small towns situated on its aprons at or near the shoreline. These towns have a combined population of nearly 5,000. The volcano has frequently produced debris flows (watery flows of mud, rock, and debris—also known as lahars when they occur on a volcano) that could inundate these nearby populated areas. Concepción volcano has erupted more than 25 times in the last 120 years. Its first recorded activity was in AD 1883. Eruptions in the past century, most of which have originated from a small summit crater, comprise moderate explosions, ash that falls out of eruption plumes (called tephra), and occasional lava flows. Near the summit area, there are accumulations of rock that were emplaced hot (pyroclastic deposits), most of which were hot enough to stick together during deposition (a process called welding). These pyroclastic rocks are rather weak, and tend to break apart easily. The loose volcanic rock remobilizes during heavy rain to form lahars. Volcanic explosions have produced blankets of tephra that are distributed downwind, which on Isla Ometepe is mostly to the west. Older deposits at the west end of the island that are up to 1 m thick indicate larger explosive events have happened at Concepción volcano in prehistoric time. Like pyroclastic-flow deposits, loose tephra on the steep slopes of the volcano provides source material that heavy rainstorms and earthquakes can mobilize to trigger debris flow.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70162577','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70162577"><span>Preventing volcanic catastrophe; the U.S. International Volcano Disaster Assistance Program</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ewert, J.W.; Murray, T.L.; Lockhart, A. B.; Miller, C.D.</p> <p>1993-01-01</p> <p>Unfortunately, a storm on November 13, 1985, obscured the glacier-clad summit of Nevado del Ruiz. On that night an explosive eruption tore through the summit and spewed approximately 20 million cubic meters of hot ash and rocks across the snow-covered glacier. These materials were transported across the snow pack by avalanches of hot volcanic debris (pyroclastic flows) and fast-moving, hot, turbulent clouds of gas and ash (pyroclastic surges). The hot pyroclastic flows and surges caused rapid melting of the snow and ice and created large volumes of water that swept down canyons leading away from the summit. As these floods of water descended the volcano, they picked up loose debris and soil from the canyon floors and walls, growing both in volume and density, to form hot lahars. In the river valleys farther down the volcano's flanks, the lahars were as much as 40 m thick and traveled at velocities as fast as 50 km/h. Two and a half hours after the start of the eruption one of the lahars reachered Armero, 74 km from the explosion crater. In a few short minutes most of the town was swept away or buried in a torrent of mud and boulders, and three quaters of the townspeople perished. </p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.4504G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.4504G"><span>Shift from magmatic to phreatomagmatic explosion controlled by the evolution of lateral fissure eruption in Suoana Crater, Miyakejima</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Geshi, Nobuo; Nemeth, Karoly; Noguchi, Rina; Oikawa, Teruki</p> <p>2016-04-01</p> <p>Combined analysis of the proximal deposit and exposed feeder-diatreme structure of the Suoana Crater of Miyakejima reveals the process of magma-water interaction controlled by the evolution of lateral fissure eruption in a stratovolcanic edifice. The Suoana Crater, an oval maar with 400 x 300 m across is one of the craters of the Suoana-Kazahaya crater chain which is formed during a fissure eruption in the 7th Century. The eruption fissure extends ~3 km from the summit area (~700 m asl) to the lower-flank area (~200m asl). The eruption fissure consists of upper maar-chain (>450 m asl) and lower scora-cone chain. As the wall of the 2000 AD caldera truncated at near the center of the Suoana Crater, the vertical section of the feeder dike - diatreme - maar system of the Suoana Crater is exposed in the caldera wall (Geshi et al., 2011). The ejected materials from the Suoana crater indicate the transition of eruption style from magmatic to phreatomagmatic. The juvenile clasts in the lower half of the deposit exhibit spatter-like shape, indicating the typical deposit from a vigorous fire fountain. Contrary, the juvenile clasts in the upper half are less vesiculated and exhibit cauliflower-shape, indicating the typical phreatomagmatic activity. This transition indicates that the magma-water interaction started at the middle of the eruption. Judging from the ratio of the thickness of the lower and upper parts, the contrast of the content of juvenile clasts, and bulk density of the deposit, the total ejected volume of magma is larger in the lower part compare to the upper part. The transition from magmatic to phreatomagmatic occurred only in the upper half of the eruption fissure, including the Suoana crater, whereas the lower half of the fissure continued dry magmatic eruption throughout their activity. The limited distribution of phreatomagmatic activity can be resulted by the magma extraction from the upper feeder dike system to the lower eruption fissure as it contributed to the general drop of magmatic pressure in the upper section of the fissure-fed conduit. The cross section of the Suoana diatreme indicates that the phreatomagmatic explosion occurred ~260 m below the original ground surface, corresponding to ~400 m above the present sea level. This elevation is clearly higher than that of the lower part of the eruption fissure which reached to the point ~ 200 m above sea level. The drop of magma flux and the general gravitational instability of the conduit resulted that ground water was able to access the still hot feeder dikes and initiate phreatomagmatic explosive eruptions (e.g., Geshi and Neri, 2014). The existence of buried summit caldera that can host large quantity of groundwater also contributes the limited distribution of phreatomagmatic activity in the summit area. We propose that this seemingly reversal trend from early magmatic to later phreatomagmatic explosive eruption style in top of large mafic caldera volcanoes in fissure fed volcanic islands is probably a far more common eruption mechanism and hence it needs to be considered in volcanic hazard scenario descriptions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70193590','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70193590"><span>Merapi 2010 eruption—Chronology and extrusion rates monitored with satellite radar and used in eruption forecasting</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Pallister, John S.; Schneider, David; Griswold, Julia P.; Keeler, Ronald H.; Burton, William C.; Noyles, Christopher; Newhall, Christopher G.; Ratdomopurbo, Antonius</p> <p>2013-01-01</p> <p>Despite dense cloud cover, satellite-borne commercial Synthetic Aperture Radar (SAR) enabled frequent monitoring of Merapi volcano's 2010 eruption. Near-real-time interpretation of images derived from the amplitude of the SAR signals and timely delivery of these interpretations to those responsible for warnings, allowed satellite remote sensing for the first time to play an equal role with in situ seismic, geodetic and gas monitoring in guiding life-saving decisions during a major volcanic crisis. Our remotely sensed data provide an observational chronology for the main phase of the 2010 eruption, which lasted 12 days (26 October–7 November, 2010). Unlike the prolonged low-rate and relatively low explosivity dome-forming and collapse eruptions of recent decades at Merapi, the eruption began with an explosive eruption that produced a new summit crater on 26 October and was accompanied by an ash column and pyroclastic flows that extended 8 km down the flanks. This initial explosive event was followed by smaller explosive eruptions on 29 October–1 November, then by a period of rapid dome growth on 1–4 November, which produced a summit lava dome with a volume of ~ 5 × 106 m3. A paroxysmal VEI 4 magmatic eruption (with ash column to 17 km altitude) destroyed this dome, greatly enlarged the new summit crater and produced extensive pyroclastic flows (to ~ 16 km radial distance in the Gendol drainage) and surges during the night of 4–5 November. The paroxysmal eruption was followed by a period of jetting of gas and tephra and by a second short period (12 h) of rapid dome growth on 6 November. The eruption ended with low-level ash and steam emissions that buried the 6 November dome with tephra and continued at low levels until seismicity decreased to background levels by about 23 November. Our near-real-time commercial SAR documented the explosive events on 26 October and 4–5 November and high rates of dome growth (> 25 m3 s− 1). An event tree analysis for the previous 2006 Merapi eruption indicated that for lava dome extrusion rates > 1.2 m3 s− 1, the probability of a large (1872-scale) eruption was ~ 10%. Consequently, the order-of-magnitude greater rates in 2010, along with the explosive start of the eruption on 26 October, the large volume of lava accumulating at the summit by 4 November, and the rapid and large increases in seismic energy release, deformation and gas emissions were the basis for warnings of an unusually large eruption by the Indonesian Geological Agency's Center for Volcanology and Geologic Hazard Mitigation (CVGHM) and their Volcano Research and Technology Development Center (BPPTK) in Yogyakarta — warnings that saved thousands of lives.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70186924','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70186924"><span>Onset of a basaltic explosive eruption from Kīlauea’s summit in 2008: Chapter 19</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Carey, Rebecca J.; Swavely, Lauren; Swanson, Don; Houghton, Bruce F.; Orr, Tim R.; Elias, Tamar; Sutton, Andrew; Carey, Rebecca; Cayol, Valérie; Poland, Michael P.; Weis, Dominique</p> <p>2015-01-01</p> <p>The onset of a basaltic eruption at the summit of Kīlauea volcano in 2008 is recorded in the products generated during the first three weeks of the eruption and suggests an evolution of both the physical properties of the magma and also lava lake levels and vent wall stability. Ash componentry and the microtextures of the early erupted lapilli products reveal that the magma was largely outgassed, perhaps in the preceding weeks to months. An increase in the juvenile:lithic ratio and size of ash collected from March 23 to April 3 records an increasing level of the magma within the conduit. After April 3 until the explosive eruption of April 9, a trend of decreasing juvenile:lithic ratio suggests that vent wall collapses were more frequent, possibly because lava level increased and destabilized the overhanging wall [Orr et al. 2013]. Despite increasing lake height, the microtextural characteristics of the lapilli suggest that the outgassed end-member was still being tapped between March 26 and April 8. The April 9 rockfall triggered an explosive eruption that produced a new component in the eruption deposits not seen in the preceding weeks; microvesicular juvenile lapilli, the first evidence of an actively vesiculating magma. Two additional dense end-member pyroclast types were also erupted during the April 9 explosion, likely related to outgassed magma with longer residence times than the microvesicular magma. We link these pyroclasts to a stagnant viscous crust at the top of the magma column or to convecting, downwelling magma. Our study of ash componentry and the textures of juvenile lapilli suggests that the April 9 explosive event effectively cleared the conduit of largely outgassed magma. The degassing processes during this eruption are complex and varied: in the period of persistent degassing during March 26-April 8 small resident bubbles at shallow levels in the lava lake were coupled to the magma whereas large bubbles ascended, expanded and fragmented. During the rockfall- triggered explosion of April 9, all bubbles were coupled to the host magma on the timescale of decompression, but additional exsolution, decompression and expansion of deeper, more gas-rich resident magma likely occurred [cf. Carey et al. 2012]. Where external conditions play a significant role in eruption dynamics, e.g., by triggering eruptions, vesiculation and degassing dynamics can be expected to be complex.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss013e23272.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss013e23272.html"><span>Earth Observations taken by the Expedition 13 crew</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2006-05-20</p> <p>ISS013-E-23272 (8 June 2006) --- Tenerife Island, Spain is featured in this image photographed by an Expedition 13 crewmember on the International Space Station. Tenerife is the largest of the Canary Islands, a Spanish possession located off the northwestern coast of Africa. According to scientists, the islands in the chain could have been produced by eruptions of basaltic shield volcanoes as the African tectonic plate moved over a stationary "hot spot" much like the formation of the Hawaiian Islands. A different hypothesis relates the Canary Islands to magma rise along underwater faults during the uplift of the Atlas Mountains in northern Africa. The island of Tenerife exhibits many excellent volcanic features. The central feature of this image is the elliptical depression of the Las Ca?adas caldera that measures 170 square kilometers in area. A caldera is typically formed when the magma chamber underneath a volcano is completely emptied (usually following a massive eruptive event), and the overlying materials collapse into the newly formed void beneath the surface. A large landslide may have also contributed to (or been the primary cause of) formation of the caldera structure. In this model, part of the original shield volcano forming the bedrock of the island collapsed onto the adjacent sea floor, forming the large depression of the caldera. According to scientists, following formation of the caldera approximately 0.17 million years ago, the composite volcanoes of Mount Teide and Pico Viejo formed. Teide is the highest peak in the Atlantic Ocean with a summit elevation of 3,715 meters. This type of volcano is formed by alternating layers of dense lava flows and more fragmented explosive eruption products, and can build high cones. Many linear flow levees are visible along the flanks of Teide volcano extending from the summit to the base, while a large circular explosion crater marks the summit of Pico Viejo. The floor of the Las Ca?adas caldera is covered with tan, red-brown, and black irregularly-lobed lava flows, the eruptions of which have been observed by settlers and seamen since 1402. The most recent eruption occurred in 1909. The island of Tenerife is actively monitored for further activity.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://pubs.dggsalaskagov.us/webpubs/dggs/ri/text/ri2011_005.pdf','USGSPUBS'); return false;" href="http://pubs.dggsalaskagov.us/webpubs/dggs/ri/text/ri2011_005.pdf"><span>The 2009 eruption of Redoubt Volcano, Alaska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bull, Katharine F.; Cameron, Cheryl; Coombs, Michelle L.; Diefenbach, Angie; Lopez, Taryn; McNutt, Steve; Neal, Christina; Payne, Allison; Power, John A.; Schneider, David J.; Scott, William E.; Snedigar, Seth; Thompson, Glenn; Wallace, Kristi; Waythomas, Christopher F.; Webley, Peter; Werner, Cynthia A.; Schaefer, Janet R.</p> <p>2012-01-01</p> <p>Redoubt Volcano, an ice-covered stratovolcano on the west side of Cook Inlet, erupted in March 2009 after several months of escalating unrest. The 2009 eruption of Redoubt Volcano shares many similarities with eruptions documented most recently at Redoubt in 1966–68 and 1989–90. In each case, the eruptive phase lasted several months, consisted of multiple ashproducing explosions, produced andesitic lava and tephra, removed significant amounts of ice from the summit crater and Drift glacier, generated lahars that inundated the Drift River valley, and culminated with the extrusion of a lava dome in the summit crater. Prior to the 2009 explosive phase of the eruption, precursory seismicity lasted approximately six months with the fi rst weak tremor recorded on September 23, 2008. The first phreatic explosion was recorded on March 15, and the first magmatic explosion occurred seven days later, at 22:34 on March 22. The onset of magmatic explosions was preceded by a strong, shallow swarm of repetitive earthquakes that began about 04:00 on March 20, 2009, less than three days before an explosion. Nineteen major ash-producing explosions generated ash clouds that reached heights between 17,000 ft and 62,000 ft (5.2 and 18.9 km) ASL. During ash fall in Anchorage, the Ted Stevens International Airport was shut down for 20 hours, from ~17:00 on March 28 until 13:00 on March 29. On March 23 and April 4, lahars with fl ow depths to 10 m in the upper Drift River valley inundated parts of the Drift River Terminal (DRT). The explosive phase ended on April 4 with a dome collapse at 05:58. The April 4 ash cloud reached 50,000 ft (15.2 km) and moved swiftly to the southeast, depositing up to 2 mm of ash fall in Homer, Anchor Point, and Seldovia. At least two and possibly three lava domes grew and were destroyed by explosions prior to the final lava dome extrusion that began after the April 4 event. The fi nal lava dome ceased growth by July 1, 2009, with an estimated volume of 72 Mm3</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.V53C3116W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.V53C3116W"><span>Temporal Evolution of Surface Deformation and Magma Sources at Pacaya Volcano, Guatemala Revealed by InSAR</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wnuk, K.; Wauthier, C.</p> <p>2016-12-01</p> <p>Pacaya Volcano, Guatemala is a persistently active volcano whose western flank is unstable. Despite continuous activity since 1961, a lack of high temporal resolution geodetic surveying has prevented detailed modeling of Pacaya's underlying magmatic plumbing system. A new, temporally dense dataset of Interferometric Synthetic Aperture Radar (InSAR) RADARSAT-2 images, spanning December 2012 to March 2014, shows magmatic deformation before and during major eruptions in January and March 2014. Inverse modeling of InSAR surface displacements suggest that three magma bodies are responsible for observed deformation: (1) a 3.7 km deep spherical reservoir located northwest of the summit, (2) a 0.4 km deep spherical source located directly west of the summit, and (3) a shallow dike below the summit that provides the primary transport pathway for erupted materials. Periods of heightened activity are brought on by magma pulses at depth, which result in rapid inflation of the edifice. We observe an intrusion cycle at Pacaya that consists of deflation of one or both magma reservoirs followed by dike intrusion. Intrusion volumes are proportional to reservoir volume loss, and do not always result in an eruption. Periods of increased activity culminate with larger dike fed eruptions. Large eruptions are followed by inter eruptive periods marked by a decrease in crater explosions and a lack of deformation. A full understanding of magmatic processes at Pacaya is required to assess potential impacts on other aspects of the volcano such as the unstable western flank. Co-eruptive flank motion appears to have initiated a new stage of volcanic rifting at Pacaya defined by repeated NW-SE dike intrusions. This creates a positive feedback relationship whereby magmatic forcing from eruptive dike intrusions induces flank motion</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.S43F..08K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.S43F..08K"><span>Characterization of Fluid Oscillations at Kilauea Volcano Through Time-Dependent Modeling of Seismic Displacements from Rockfall Events</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karlstrom, L.; Dunham, E. M.; Thelen, W. A.; Patrick, M. R.; Liang, C.; Prochnow, B. N.</p> <p>2015-12-01</p> <p>Beginning with the opening of a summit vent in 2008, Kilauea's (Hawaíi) summit eruption has exhibited frequent rockfalls from the crater walls into the active lava lake. These events perturb the lake surface, causing vigorous outgassing and sometimes explosions. A network of broadband seismometers records these events as a combination of high-frequency, long-period, and very long period (VLP) oscillations. The VLP portion of the signal has varied in period from 20-40 s since the summit vent opened and has a duration of 10-15 min. These seismic signals reflect the coupling of fluid motion in the conduit to elastic wall rocks. Oscillatory flow can be quantified in terms of the eigenmodes of a magma-filled conduit. Wave motion is affected by conduit geometry, multiphase fluid compressibility, viscosity, and pressure dependent H2O and CO2 solubility. Background stratification and a large impedance contrast at the depth where volatiles first exsolve gives rise to spatially localized families of conduit eigenmodes. The longest period modes are sensitive to properties of bubbly magma and to the length of the conduit above exsolution (which is set by total volatile content). To study the VLP events, we linearize the conduit flow equations assuming small perturbations to an initially magmastatic column, accounting for non-equilibrium multiphase fluid properties, stratification and buoyancy, and conduit width changes. We solve for conduit eigenmodes and associated eigenfrequencies, as well as for the time-domain conduit response to forces applied to the surface of the lava lake. We use broadband records of rockfalls from 2011-2015 that exhibit consistent periods along with lake level measurements to estimate conduit parameters. Preliminary results suggest that VLP periods can be matched with volatile contents similar to those inferred from melt inclusions from Halemaumau explosions. We are currently conducting a more thorough exploration of the parameter space to investigate this further.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFMAE44A..08R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFMAE44A..08R"><span>Lighting Observations During the Mt. Augustine Volcanic Eruptions With the Portable Lightning Mapping Stations</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rison, W.; Krehbiel, P.; Thomas, R.; Edens, H.; Aulich, G.; O'Connor, N.; Kieft, S.; McNutt, S.; Tytgat, G.; Clark, E.</p> <p>2006-12-01</p> <p>Following the initial eruptions of Mt. Augustine on January 11-17 2006, we quickly prepared and deployed a first contingent of two portable mapping stations. This was our first use of the newly-developed portable stations, and we were able to deploy them in time to observe the second set of explosive eruptions during the night of January~27-28. The stations were located 17~km apart on the west coast of the Kenai Peninsula, 100~km distant from Augustine on the far western side of Cook Inlet. The stations comprised a minimal network capable of determining the azimuthal direction of VHF radiation sources from electrical discharges, and thus the transverse location of the electrical activity relative to the volcano. The time series data from the southern, Homer station for the initial, energetic explosion at 8:31 pm on January~27 revealed the occurrence of spectacular lightning, which from the two-station data drifted southward from Augustine with time, in the same direction as the plume from the eruption. About 300 distinct lightning discharges occurred over an 11-minute time interval, beginning 2-3~min after the main explosion. The lightning quickly became increasingly complex with time and developed large horizontal extents. One of the final discharges of the sequence lasted 600~ms and had a transverse extent of 15~km, extending to 22~km south of Augustine's summit. In addition to this more usual form of lightning, continuous bursts of radio frequency radiation occurred during the explosion itself, indicating that the tephra was highly charged upon being ejected from the volcano. A completely unplanned and initially missed but one of several fortuitous aspects of the observations was that the Homer station functioned as a 'sea-surface interferometer' whose interference pattern can be used to determine the altitude variation with time for some discharges. The station's VHF antenna was located on the edge of a bluff 210~m above Cook Inlet and received both the direct and reflected signals from the water surface. A clear pattern of interference fringes was observed for the strongest lightning event during the explosive phase and has shown that it was an upward-triggered discharge that propagated upward from Augustine's summit and into the downwind plume. The radiation sources were characteristic of negative polarity breakdown into inferred positive charge in the plume. None of the lightning activity from the January~27-28 eruptions was observed visually due to stormy weather conditions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.V41F..01N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.V41F..01N"><span>Introduction to Augustine Volcano and Overview of the 2006 Eruption</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nye, C. J.</p> <p>2006-12-01</p> <p>This overview represents the combined efforts of scores of people, including Alaska Volcano Observatory staff from the US Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys; additional members of those agencies outside of AVO; and volcanologists from elsewhere. Augustine is a young, and therefore small island volcano in the Cook Inlet region of the eastern Aleutian arc. It is among the most active volcanoes in the arc, with six major historic eruptions, and a vigorous eruptive history going back at least 2,500 years. Eruptions typically begin explosively, and finish with the extrusion of domes and sometimes short, steep lava flows. At least 14 times (most recently in 1883) the -summit has become over-steepened and failed, producing debris avalanches which reached tidewater. Magmas within each of the well-studied eruptions are crystal-rich andesite spanning up to seven weight percent silica. Mixing and mingling are ubiquitous and occur at scales from meters to microns. In general, magmagenesis at Augustine is open, messy, and transcrustal. The 2006 eruption was broadly similar to the 20th century eruptions. Unrest began midway through 2005, with steadily increasing numbers of microearthquakes and continuous inflation of the edifice. By mid-December there were obvious morphological and thermal changes at the summit, as well as phreatic explosions and more passive venting of S-rich gasses. In mid-January 2006 phreatomagmatic explosions gave way to magmatic explosions, producing pyroclastic flows dominated by low-silica andesite, as well as lahars, followed by a small summit dome. In late January the nature of seismicity, eruptive style, and type of erupted magma all changed, and block-and-ash flows of high-silica, crystal-rich andesite were emplaced as the edifice deflated. Re-inflation well below the edifice and low-level effusion continued through February. During the second week in March there was a marked increase in extrusion, resulting in two short, steep lava flows dominantly composed of low-silica andesite. Effusion slowly waned through March and deformation ceased. Previous eruptions have had months-long repose followed be renewed effusion, but this has not yet happened during this eruption. Our ability to describe this eruption is based on a richness of data. The volcano was well instrumented with AVO seismometers and Earthscope/PBO continuous GPS instruments. Additional instruments were added as unrest increased, and substitutes for stations destroyed during initial explosions were deployed. As many as two-dozen AVHRR satellite passes were analyzed each day, providing thermal monitoring and ash-plume tracking. Overflights collected both visual and quantitative IR imagery on a regular basis. Georeferenced imagery acquired by satellite (ASTER) and repeated conventional aerial photography permitted detailed, accurate, mapping of many deposits as an aid to (but not substitute for) field mapping. Web cameras (both visual and near-IR) and conventional time-lapse cameras aided understanding of ongoing processes. Data sets less common to volcano monitoring (infrasound, lightning detection) extended our understanding.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1614526S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1614526S"><span>Insights into different Strombolian explosive styles by remote controlled OP-FTIR (CERBERUS) measurements</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Spina Alessandro, La; Mike, Burton; Filippo, Murè; Roberto, Maugeri</p> <p>2014-05-01</p> <p>In this paper we present the results and interpretation of gas composition data collected by a permanent OP-FTIR system (CERBERUS) installed at Stromboli summit. The instrument allows remote control observation and measurement of gas emissions from different points within volcano's crater terrace, using an integrated infrared camera / scanning mirror / FTIR system. Given that an OpenPath Fourier Transform InfraRed (FTIR) spectrometer allows the simultaneously measure all the major species contained in volcanic gas emissions, we could observe the different explosive styles fed by Stromboli volcano. Stromboli volcano, in the Aeolian island arc, is known as the "Lighthouse of the Mediterranean" for its regular (~every 10-20 min) explosive activity, launching crystal-rich black scoriae to 100-200 m height constituting a rich and impressive spectacle for both volcanologists and tourists from every part of the world. This ordinary activity has been classified in two types in relation to the their content of ash ejected. Type 1 is dominated melt ballistic particles whereas Type 2 consists of an ash-rich plume. On 18 July we recorded both explosive styles at the SW crater of Stromboli finding quite similar CO2/SO2 ratio, although we observed a higher value of SO2/HCl molar ratio for the Type 2. Moreover prior to both types of explosions the CO2 amount showed similar trend, whereas a different pattern in SO2 and in HCl gas content, was observed. In detail type 2 was preceded by decrease in SO2 and HCl amounts with respect to type 1. The decreasing trend observed before the onset of style 2 and the higher SO2/HCl ratio might be an indication of overpressure that might have induced the difference between the two types of explosions. In this context, the evidence of no change in the amount of CO2 and in CO2/SO2 ratio suggested us that this overpressure occurred in very shallow depths within the volcano feeding system. If our observations will be confirmed by other explosive event data, we will be able featuring the different source conditions triggering the ordinary explosive activity at Stromboli.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.V41B2800C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.V41B2800C"><span>Hydroacoustic Recordings of Explosion-Induced Tremor at NW Rota-1 Volcano, Marianas</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Caplan-Auerbach, J.; Dziak, R. P.; Lau, T. A.</p> <p>2013-12-01</p> <p>Hydroacoustic data recorded during the long-term eruption of NW Rota-1 submarine volcano (Marianas) reveal a wide variety of explosion and tremor signals. Data from a moored hydrophone deployed near the summit of NW Rota-1 from February 2009 to April 2010 confirm that NW Rota-1 was nearly continuously active during this time. Explosion acoustic signals have a wide range of frequencies: some carry energy that is bandlimited between 5-25 Hz while others show broadband signal strength between 5-200 Hz (even higher frequencies may be attenuated by the hydrophone's anti-aliasing filter at 220 Hz). The signal is observed to switch rapidly between low frequency and broadband explosion types. In many cases the explosion signals repeat at a high rate, with recurrence intervals between 0.1-0.5 seconds. In such instances the explosions blend into tremor, exhibiting a large number of spectral harmonics that we attribute to the Dirac comb effect. The presence of these harmonics indicates that explosion recurrence intervals are highly regular, although subtle gliding within the harmonic frequencies suggests that there is some variability in the timing between explosions. This suggests a strongly repeatable explosion source. The frequency of explosions at NW Rota-1 is confirmed by ROV observations of eruption plume dynamics (Chadwick et al., 2008; Deardorff et al., 2008). We also observe a strong low-frequency (< 5 Hz) tremor signal that does not correlate with the explosion tremor, as well as strongly harmonic tremor that is not obviously composed of repeating explosions. These signals may reflect processes deeper within the conduit, yet still capable of coupling into the water column. Video footage collected during ROV dives in 2009 shows multiple instances in which the ground is observed to move, but these signals do not clearly correlate with hydroacoustic pulses. Deeper study into the source of these signals requires seismic instrumentation on and around NW Rota-1.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUSM.V21A..08S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUSM.V21A..08S"><span>Unusual Volcanic Products From the 2008 Eruption at Volcan Llaima, Chile</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sweeney, D. C.; Hughes, M.; Calder, E. S.; Cortes, J.; Valentine, G.; Whelley, P.; Lara, L.</p> <p>2009-05-01</p> <p>Volcan Llaima, a snow-covered basaltic andesite stratocone in southern Chile (38 41' S, 71 44' W, 3179 m a.s.l.), erupted on 1 January 2008 with a fire fountain display lasting 14 hours. Elevated activity continues to date with mild to moderate strombolian activity occurring from two nested scoria cones in the summit crater and with occasional lava flows from crater overflow. The eruption displayed contrasting styles of activity emanating from different parts of the edifice that may provide some unique insight into the upper level plumbing system. Furthermore, the activity has provided an excellent chance to study the transition of a normally passive degassing system into a violent eruptive cycle. A field study of the eruptive products from this eruption was completed in January 2009, where sampling was carried out from the tephra fall, lava flows, lahar deposits and even small pyroclastic flow deposits. The scoria samples collected suggest a mixture of two magmas involved in the initial violent, fire fountaining activity from the summit. Additionally, they exhibit a variety of unusual textures, including rapidly-quenched, dense lava 'balls' - generated at the front of the lava flows traveling through ice, as well as cauliflower-textured tephra from explosive eruptions though ice. This presentation comprises our observations and preliminary interpretations concerning the processes that occurred during this unique eruption.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1911564N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1911564N"><span>Phreatomagmatic explosive eruptions along fissures on the top of mafic stratovolcanoes with overlapping compound calderas</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nemeth, Karoly; Geshi, Nobuo</p> <p>2017-04-01</p> <p>On near summit flank eruptions on stratovolcanoes it is commonly inferred that external water to have little or no influence on the course of the eruptions. Hence eruptions are typicaly "dry" that form spatter-dominated fissures and scoria cones. This assumption is based on that in elevated regions - especially on steep slopes - the hydrogeological conditions are not favourable to store large volume of ground water that can have effect on the eruptions. However there is some controversial trend of eruption progression from an early dry eruption below the summit that later turn to be phreatomagmatic as the eruption locus migrates toward the summit. The Suoana Ccrater on top of Miyakejima Island's mafic stratovolcano is a fine example to demonstrate such process. Suona Crater is the topmost crater of the 3 km long fissure aligned chain of small-volume volcanoes that formed in the 7th century flank of the summit region of the Miyakejima mafic stratovolcano. The oval shape crater of Suona (400 x 300 m) is surrounded by a tuff ring that developed over lava flows and epiclastic deposits accumulated in an older caldera forming about a tuff ring that is about 25 m in its thickest section with a basal consistent lava spatter dominated unit gradually transforming into a more scoria-dominated middle unit. A caldera-forming eruption in AD 2000 half-sectioned the Suona Crater exposing of its internal diatreme - crater in-fill - tephra rim succession providing a unique opportunity to understand the 3D architecture of the volcano. Toward the top of the preserved and exposed tuff ring section a clear gradual transition can be seen toward more abundance of chilled dark juvenile particles providing a matrix of a coarse ash that commonly hold cauliflower lapilli and bomb. This transition indicates that the eruption progressed from an early dry explosive phase such as lava fountaining to be a more Strombolian style explosive eruption that later on turned to be heavily influenced by external water producing debris jet dominated phreatomagmatic tephra and radially expanding pyroclastic density currents to deposit their load around the growing crater. This 3D architecture can only be explained if we infer that the original lower fissure-fed eruptions gradually allow melt to move toward the summit region where they hit ground water accumulated in an older caldera infill that hosted a succession of lava flows intercalated with lava foot and top breccias as well as abundant pyroclastic and reworked porous deposits capable to harvest water from rain and let them ponded along aquitard horizons in the caldera structure. We infer that such eruption mechanism is probably a common eruption style especially associated with volcanic islands with mafic stratovoclanoes that contain some summit caldera structures and located in humic and/or tropical climate.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.V34A..06P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.V34A..06P"><span>A refined model for Kilauea's magma plumbing system</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Poland, M. P.; Miklius, A.; Montgomery-Brown, E. D.</p> <p>2011-12-01</p> <p>Studies of the magma plumbing system of Kilauea have benefitted from the volcano's frequent eruptive activity, ease of access, and particularly the century-long observational record made possible by the Hawaiian Volcano Observatory. The explosion of geophysical data, especially seismic and geodetic, collected since the first model of Kilauea's magmatic system was published in 1960 allows for a detailed characterization of Kilauea's magma storage areas and transport pathways. Using geological, geochemical, and geophysical observations, we propose a detailed model of Kilauea's magma plumbing that we hope will provide a refined framework for studies of Kilauea's eruptive and intrusive activity. Kilauea's summit region is underlain by two persistently active, hydraulically linked magma storage areas. The larger reservoir is centered at ~3 km depth beneath the south caldera and is connected to Kilauea's two rift zones, which radiate from the summit to the east and southwest. All magma that enters the Kilauea edifice passes through this primary storage area before intrusion or eruption. During periods of increased magma storage at the summit, as was the case during 2003-2007, uplift may occur above temporary magma storage volumes, for instance, at the intersection of the summit and east rift zone at ~3 km depth, and within the southwest rift zone at ~2 km depth. The east rift zone is the longer and more active of Kilauea's two rift zones and apparently receives more magma from the summit. Small, isolated pods of magma exist within both rift zones, as indicated by deformation measurements, seismicity, petrologic data, and geothermal drilling results. These magma bodies are probably relicts of past intrusions and eruptions and can be highly differentiated. Within the deeper part of the rift zones, between about 3 km and 9 km depth, magma accumulation is hypothesized based on surface deformation indicative of deep rift opening. There is no direct evidence for magma within the deep rift zones, however, suggesting the possibility that the region is "dry" and that the opening deformation is accommodated by processes other than filling by magma. A smaller summit magma storage area is located at 1-2 km depth beneath the east margin of Halema'uma'u Crater, near the center of the caldera. The smaller reservoir is connected to, but perched above, the larger south caldera reservoir and rift zones, and therefore has more hydraulic head and drains rapidly during rift zone intrusions and eruptions. Secondary, shallow (~1 km depth) rift systems branch from this magma reservoir, as indicated by alignments of eruptive vents and fracture systems to the east and west from Halema'uma'u Crater. Although usually inactive, large historical eruptions have occurred from these rift systems, including Kilauea Iki in 1959 (east) and Mauna Iki in 1919-20 (west).</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_4 --> <div id="page_5" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="81"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.V43E..06H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.V43E..06H"><span>Vesiculation Processes During Transient and Sustained Explosive Activity at Halema'uma'u Crater, Kīlauea in 2008-2013.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Houghton, B. F.; Orr, T. R.; Taddeucci, J.; Carey, R.; Del Bello, E.; Scarlato, P.; Patrick, M. R.</p> <p>2015-12-01</p> <p>The 2008-2015 summit eruption within Halema'uma'u crater, Kilauea has been characterized by alternations of passive degassing with two styles of explosive activity, both frequently triggered by rock falls that perturb the free surface of magma in the vent. In the first, larger rock falls trigger second vesiculation of magma at depths up to 100 m below the free surface ejecting juvenile bomb and lapilli populations of very variable vesicularity. The second, the topic of this presentation, consists of intervals of minutes to tens-of-minutes duration of low fountaining activity often from multiple locations. Vents may migrate with time, first across the free surface to its margins, and then around the margins, in response to convection processes in the underlying melt. Analysis of short sequences of high-speed, high-resolution video footage shows that the sustained fountaining is maintained by not by a continuous discharge but rather by closely spaced bursting of two-to-five meter-wide bubbles. Bubbles accelerate through the free surface at velocities of 10 to 40 m/s disrupting the viscoelastic crust and forming large fall-back, lacework pyroclasts and smaller highly vesicular bombs and lapilli.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70021269','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70021269"><span>Kilauea summit overflows: Their ages and distribution in the Puna District, Hawai'i</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Clague, D.A.; Hagstrum, J.T.; Beeson, M.H.; Champion, D.E.</p> <p>1999-01-01</p> <p>The tube-fed pahoehoe lava flows covering much of the northeast flank of Kilauea Volcano are named the 'Aila'au flows. Their eruption age, based on published and six new radiocarbon dates, is approximately AD 1445. The flows have distinctive paleomagnetic directions with steep inclinations (40??-50??) and easterly declinations (0??-10??E). The lava was transported ~40 km from the vent to the coast in long, large-diameter lava tubes; the longest tube (Kazumura Cave) reaches from near the summit to within several kilometers of the coast near Kaloli Point. The estimated volume of the 'Aila'au flow field is 5.2 ?? 0.8 km3, and the eruption that formed it probably lasted for approximately 50 years. Summit overflows from Kilauea may have been nearly continuous between approximately AD 1290 and 1470, during which time a series of shields formed at and around the summit. The 'Aila'au shield was either the youngest or the next to youngest in this series of shields. Site-mean paleomagnetic directions for lava flows underlying the 'Aila'au flows form only six groups. These older pahoehoe flows range in age from 2750 to 2200 years. Lava flows from most of these summit eruptions also reached the coast, but none appears as extensive as the 'Aila'au flow field. The chemistry of the melts erupted during each of these summit overflow events is remarkably similar, averaging approximately 6.3 wt.% MgO near the coast and 6.8 wt.% MgO near the summit. The present-day caldera probably formed more recently than the eruption that formed the 'Aila'au flows (estimated termination ca. AD 1470). The earliest explosive eruptions that formed the Keanakako'i Ash, which is stratigraphically above the 'Aila'au flows, cannot be older than this age.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRB..120.1142U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRB..120.1142U"><span>Volcanic tremor and frequency gliding during dike intrusions at Kı¯lauea—A tale of three eruptions</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Unglert, K.; Jellinek, A. M.</p> <p>2015-02-01</p> <p>To characterize syneruptive/intrusive deviations from background volcanic tremor at Kı¯lauea, Hawai`i, we analyze the spatial and temporal properties of broadband tremor during dike intrusions into the East Rift Zone (ERZ) in 2007 and 2011, as well as during explosive eruptive activity at Kı¯lauea's summit in 2008. Background tremor was similar for each event, and the 2008 explosions did not affect its properties. In contrast, the intrusions were accompanied by departures from this background in the form of two phases of seismicity that were separated in space and time. In both 2007 and 2011, Phase I was characterized by a quick succession of discrete events, which were most intense at the onset of intrusion near the presumed locations of the dikes intruding into the ERZ. Phase II, marked by continuous broadband tremor around the summit, followed 10-14 h later. In 2007, Phase II tremor was accompanied by a monotonic downward shift (glide) of spectral peaks between ˜0.6 and 1.5 Hz over at least 15 h. During Phase II in 2011, a gradual upward and subsequent symmetric downward glide between ˜0.6 and 6.6 Hz occurred over 5-10 h, respectively. The spectra during both phases differed from the background and 2008, as well as from each other, indicating different physical mechanisms. Phase I in 2007 and 2011 is probably related to the mechanics of dike intrusion. Phase II tremor may be characteristic for evolving magma-bubble dynamics related to the geometry of the plumbing system and the style of magma flow.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA126454','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA126454"><span>Seismic Methods of Infrasonic Signal Detection</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1982-09-30</p> <p>11 Alaid (Kurile Is.): Plume on satellite i agery ......................................................... 11 Kilauea ( Hawaii ): Small...historic eruption ... 6-7 Kilauea ( Hawaii ): Small fissure eruption in summit caldera ................. 7-8 Galunggung (Indonesia): Explosions and...4 June. El Chich6n Volcano (continued) TABLE 1 LOCATION AND DATE LAYER ALTITUDE IN KM BACKSCATTER (peak in parentheses) Mauna Loa, Hawaii 20.5-22</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.V21E2537G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.V21E2537G"><span>Uranium-Series Isotopic Constraints on Recent Changes in the Eruptive Behaviour of Merapi Volcano, Java, Indonesia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gertisser, R.; Handley, H. K.; Reagan, M. K.; Berlo, K.; Barclay, J.; Preece, K.; Herd, R.</p> <p>2011-12-01</p> <p>Merapi volcano (Central Java) is one of the most active and deadly volcanoes in Indonesia. The 2010 eruption was the volcano's largest eruption since 1872 and erupted much more violently than expected. Prior to 2010, volcanic activity at Merapi was characterised by several months of slow dome growth punctuated by gravitational dome failures, generating small-volume pyroclastic density currents (Merapi-type nuées ardentes). The unforeseen, large-magnitude events in 2010 were different in many respects: pyroclastic density currents travelled > 15 km beyond the summit causing widespread devastation in proximal areas on Merapi's south flank and ash emissions from sustained eruption columns resulted in ash fall tens of kilometres away from the volcano. The 2010 events have proved that Merapi's relatively small dome-forming activity can be interrupted at relatively short notice by larger explosive eruptions, which appear more common in the geological record. We present new geochemical and Uranium-series isotope data for the volcanic products of both the 2006 and 2010 eruptions at Merapi to investigate the driving forces behind this unusual explosive behaviour and their timescales. An improved knowledge of these processes and of changes in the pre-eruptive magma system has important implications for the assessment of hazards and risks from future eruptive activity at Merapi.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70016249','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70016249"><span>Phreatomagmatic and phreatic fall and surge deposits from explosions at Kilauea volcano, Hawaii, 1790 a.d.: Keanakakoi Ash Member</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>McPhie, J.; Walker, G.P.L.; Christiansen, R.L.</p> <p>1990-01-01</p> <p>In or around 1790 a.d. an explosive eruption took place in the summit caldera of Kilauea shield volcano. A group of Hawaiian warriors close to the caldera at the time were killed by the effects of the explosions. The stratigraphy of pyroclastic deposits surrounding Kilauea (i.e., the Keanakakoi Ash Member) suggests that the explosions referred to in the historic record were the culmination of a prolonged hydrovolcanic eruption consisting of three main phases. The first phase was phreatomagmatic and generated well-bedded, fine fallout ash rich in glassy, variably vesiculated, juvenile magmatic and dense, lithic pyroclasts. The ash was mainly dispersed to the southwest of the caldera by the northeasterly trade winds. The second phase produced a Strombolian-style scoria fall deposit followed by phreatomagmatic ash similar to that of the first phase, though richer in accretionary lapilli and lithics. The third and culminating phase was phreatic and deposited lithic-rich lapilli and block fall layers, interbedded with cross-bedded surge deposits, and accretionary lapilli-rich, fine ash beds. These final explosions may have been responsible for the deaths of the warriors. The three phases were separated by quiescent spells during which the primary deposits were eroded and transported downwind in dunes migrating southwestward and locally excavated by fluvial runoff close to the rim. The entire hydrovolcanic eruption may have lasted for weeks or perhaps months. At around the same time, lava erupted from Kilauea's East Rift Zone and probably drained magma from the summit storage. The earliest descriptions of Kilauea (30 years after the Keanakakoi eruption) emphasize the great depth of the floor (300-500 m below the rim) and the presence of stepped ledges. It is therefore likely that the Keanakakoi explosions were deepseated within Kilauea, and that the vent rim was substantially lower than the caldera rim. The change from phreatomagmatic to phreatic phases may reflect the progressive degassing and cooling of the magma during deep withdrawal: throughout the phreatomagmatic phases magma vesiculation contributed to the explosive interaction with water by initiating the fragmentation process: thereafter, the principal role of the subsiding magma column was to supply heat for steam production that drove the phreatic explosions of the final phase. ?? 1990 Springer-Verlag.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFM.V22A0571B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.V22A0571B"><span>Spreading of Somma-Vesuvio Volcanic Complex: is the Hazard for Plinian Eruptions being reduced?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Borgia, A.; Tizzani, P.; Solaro, G.; Luongo, G.; Fusi, N.</p> <p>2003-12-01</p> <p>Contrary to what is the common knowledge, a detailed structural study of active faulting and rifting of the summit area of Somma-Vesuvio volcanic complex, combined with INSAR, levelling data and seismic profiling at sea suggests that the present-day long-term dynamic behaviour of the complex and of its summit caldera is characterized by volcanic spreading. The structural evolution is controlled by a number of asymmetric, intersecting leaf-grabens. The boundary faults of these grabens intersect at different angles the Somma caldera walls generating a set of wedge-horsts. While normal faulting characterizes the Somma caldera walls, the lavas of the past 150 years, infilling the caldera, have been rifted all around the southern, eastern and northern base of Vesuvio's cone, which, in turn, is being displaced seaward. Associated to the subsidence and extension of the summit area, relative uplift occurs along the coast; in addition, deformation of recent sediments 6-18 km offshore also indicate compression and uplift, which appears to be unrelated to regional tectonics. A preliminary evaluation indicates that rifting of the lavas is in the order of 1-2 mm/a with a southwestward average direction of displacement. Based on these data, we suggest that a wide sector of Somma-Vesuvio is spreading on its plastic sedimentary substratum, which have been identified by drilling. Volcanic spreading appears to have controlled the magmatic evolution and the energy decrease of major historic explosive eruptions since 79 AD. If our interpretation is correct, major plinian eruptions should not occur in the near future. On the other hand, rifting around the caldera suggests that volcanic activity could soon be renewed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA22157.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA22157.html"><span>Investigating Mars: Arsia Mons</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2018-01-03</p> <p>This THEMIS image shows part of the caldera floor of Arsia Mons. It is not uncommon for calderas to have "flat" floors after the final explosive eruption the empties the subsurface magma chamber. There may still be some magma or superheated rock left after the collapse that will fill in part of the depression. Additionally, over time erosion will work to level the topography. Within Arsia Mons there was renewed activity that occurred within the caldera along the alignment of the NE/SW trend of the three large volcanoes. This ongoing, low volume actitivity is similar to the lava lake in Kilauea in Hawaii. Small flows are visible throughout this image. In the center of the image is a small "L" shaped feature. This is the summit vent for the volcanic flows around it. The flows have lapped up against the caldera wall, filling in faults left by the caldera formation and increasing the elevation of the surface in this region of the caldera. Arsia Mons is the southernmost of the Tharsis volcanoes. It is 270 miles (450km) in diameter, almost 12 miles (20km) high, and the summit caldera is 72 miles (120km) wide. For comparison, the largest volcano on Earth is Mauna Loa. From its base on the sea floor, Mauna Loa measures only 6.3 miles high and 75 miles in diameter. A large volcanic crater known as a caldera is located at the summit of all of the Tharsis volcanoes. These calderas are produced by massive volcanic explosions and collapse. The Arsia Mons summit caldera is larger than many volcanoes on Earth. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 19874 Latitude: -8.57834 Longitude: 240.452 Instrument: VIS Captured: 2006-06-07 18:39 https://photojournal.jpl.nasa.gov/catalog/PIA22157</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009JVGR..180..246N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009JVGR..180..246N"><span>Phreatomagmatic volcanic hazards where rift-systems meet the sea, a study from Ambae Island, Vanuatu</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Németh, Károly; Cronin, Shane J.</p> <p>2009-03-01</p> <p>Ambae Island is a mafic stratovolcano located in the northern Vanuatu volcanic arc and has a NE-SW rift-controlled elongated shape. Several hundred scoria cones and fissure-fed lava fields occur along its long axis. After many decades of quiescence, Ambae Island erupted on the 28th of November 2005, disrupting the lives of its 10,000 inhabitants. Its activity remained focused at the central (crater-lake filled) vent and this is where hazard-assessments were focused. These assessments initially neglected that maars, tephra cones and rings occur at each tip of the island where the eruptive activity occurred < 500 and < 300 yr B.P. The products of this explosive phreatomagmatic activity are located where the rift axis meets the sea. At the NE edge of the island five tephra rings occur, each comparable in size to those on the summit of Ambae. Along the NE coastline, a near-continuous cliff section exposes an up to 25 m thick succession of near-vent phreatomagmatic tephra units derived from closely spaced vents. This can be subdivided into two major lithofacies associations. The first association represents when the locus of explosions was below sea level and comprises matrix-supported, massive to weakly stratified beds of coarse ash and lapilli. These are dominant in the lowermost part of the sequence and commonly contain coral fragments, indicating that the loci of explosion were located within a reef or coral sediment near the syn-eruptive shoreline. The second type indicate more stable vent conditions and rapidly repeating explosions of high intensity, producing fine-grained tephra with undulatory bedding and cross-lamination as well as megaripple bedforms. These surge and fall beds are more common in the uppermost part of the succession and form a few-m-thick pile. An older tephra succession of similar character occurs below, and buried trees in growth position, as well as those flattened within base surge beds. This implies that the centre of this eruption was very near the coastline. The processes implied by these deposits are amongst the most violent forms of volcanism on this island. In addition, the lowland and coastal areas affected by these events are the most heavily populated. This circumstance is mirrored on many similar volcanic islands, including the nearby SW Pacific examples of Taveuni (Fiji), Upolu and Savai'i (Samoa), and Ambrym (Vanuatu). These locations are paradoxically often considered safe areas during summit/central-vent eruptions, simply because they are farthest from the central sources of ash-fall and lahar hazard. The observations presented here necessitate a revision of this view.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.V53A3078P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.V53A3078P"><span>An Isotopic Perspective into the Magmatic Evolution and Architecture of the Rift Zones of Kīlauea Volcano</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pietruszka, A. J.; Marske, J. P.; Garcia, M. O.; Heaton, D. E.; Rhodes, M. M.</p> <p>2016-12-01</p> <p>We present Pb, Sr, and Nd isotope ratios for Kīlauea's historical rift zone lavas (n=50) to examine the magmatic evolution and architecture of the volcano's East Rift Zone (ERZ) and Southwest Rift Zone (SWRZ). Our results show that Kīlauea's historical eruptive period was preceded by the delivery of a major batch of magma from the summit reservoir to the ERZ. The timing of this intrusion, most likely in the late 17th century, was probably related to the 300-yr period of explosive eruptions that followed the formation of the modern caldera (Swanson et al., 2012; JVGR). This rift-stored magma was a component in lavas from lower ERZ (LERZ) eruptions in 1790(?), 1840, 1955, and 1960. The only other components in these LERZ lavas are related to summit lavas erupted (1) after the 1924 collapse of Halemáumáu and (2) during episodes of high fountaining at Kīlauea Iki in 1959. Thus, the intrusion of magma from the summit reservoir into the LERZ is a rare occurrence that is tied to major volcanological events. Intrusions from the summit reservoir in the 1960s likely flushed most older, stored magma from the upper ERZ (UERZ) and middle ERZ (MERZ), leaving large pockets of 1960s-era magma to serve as a dominant component in many subsequent rift lavas. An increase in the duration of pre-eruptive magma storage from the UERZ ( 0-7 yr) to the MERZ ( 0-19 yr) to the LERZ (up to 335 yr) is likely controlled by a decrease in the rate of magma supply to the more distal portions of the ERZ. Lavas from several UERZ eruptions in the 1960s and 1970s have a component of mantle-derived magma that bypassed the summit reservoir. There is no evidence for a summit bypass into the MERZ, LERZ, or the volcanically active portion of the SWRZ. These results support a recent model for Kīlauea's plumbing system (Poland et al., 2014; USGS Prof. Pap. 1801): the ERZ is connected to the deeper "South Caldera" magma body and the volcanic SWRZ is connected to the shallower Halemáumáu magma body.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.V41C..01J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.V41C..01J"><span>Workshops on Volcanoes at Santiaguito (Guatemala): A community effort to inform and highlight the outstanding science opportunities at an exceptional laboratory volcano</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Johnson, J. B.; Escobar-Wolf, R. P.; Pineda, A.</p> <p>2016-12-01</p> <p>Santiaguito is one of Earth's most reliable volcanic spectacles and affords opportunity to investigate dome volcanism, including hourly explosions, pyroclastic flows, block lava flows, and sporadic paroxysmal eruptions. The cubic km dome, active since 1922, comprises four coalescing structures. Lava effusion and explosions are ideally observed from a birds-eye perspective at the summit of Santa Maria volcano (1200 m above and 2700 km from the active Caliente vent). Santiaguito is also unstable and dangerous. Thousands of people in farms and local communities are exposed to hazards from frequent lahars, pyroclastic flows, and potentially large sector-style dome collapses. In January 2016 more than 60 volcano scientists, students, postdocs, and observatory professionals traveled to Santiaguito to participate in field study and discussion about the science and hazards of Santiaguito. The event facilitated pre- and syn-workshop field experiments, including deployment of seismic, deformation, infrasound, multi-spectral gas and thermal sensing, UAV reconnaissance, photogrammetry, and petrologic and rheologic sampling. More than 55 participants spent the night on the 3770-m summit of Santa Maria to partake in field observations. The majority of participants also visited lahar and pyroclastic flow-impacted regions south of the volcano. A goal of the workshop was to demonstrate how multi-disciplinary observations are critical to elucidate volcano eruption dynamics. Integration of geophysical and geochemical observation, and open exchange of technological advances, is vital to achieve the next generation of volcano discovery. Toward this end data collected during the workshop are openly shared within the broader volcanological community. Another objective of the workshop was to bring attention to an especially hazardous and little-studied volcanic system. The majority of workshop attendees had not visited the region and their participation was hoped to seed future collaboration and study in Guatemala. This presentation highlights both the multi-disciplinary science and scientists' experiences at Santiaguito and argues for future similar meetings at other open-vent volcanoes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.V43A3129A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.V43A3129A"><span>Changes in lava effusion rate, explosion characteristics and degassing revealed by time-series photogrammetry and feature tracking velocimetry of Santiaguito lava dome</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Andrews, B. J.; Grocke, S.; Benage, M.</p> <p>2016-12-01</p> <p>The Santiaguito dome complex, Guatemala, provides a unique opportunity to observe an active lava dome with an array of DSLR and video cameras from the safety of Santa Maria volcano, a vantage point 2500 m away from and 1000 m above the dome. Radio triggered DSLR cameras can collect synchronized images at rates up to 10 frames/minute. Single-camera datasets describe lava dome surface motions and application of Feature-Tracking-Velocimetry (FTV) to the image sequences measures apparent lava flow surface velocities (as projected onto the camera-imaging plane). Multi-camera datasets describe the lava dome surface topography and 3D velocity field; this 4D photogrammetric approach yields georeferenced point clouds and DEMs with specific points or features tracked through time. HD video cameras document explosions and characterize those events as comparatively gas-rich or ash-rich. Comparison of observations collected during January and November 2012 and January 2016 reveals changes in the effusion rate and explosion characteristics at the active Santiaguito dome that suggest a change in shallow degassing behavior. The 2012 lava dome had numerous incandescent regions and surface velocities of 3 m/hr along the southern part of the dome summit where the dome fed a lava flow. The 2012 dome also showed a remarkably periodic (26±6 minute) pattern of inflation and deflation interpreted to reflect gas accumulation and release, with some releases occurring explosively. Video observations show that the explosion plumes were generally ash-poor. In contrast, the January 2016 dome exhibited very limited incandescence, and had reduced surface velocities of <1 m/hr. Explosions occurred infrequently, but were generally longer duration ( e.g. 90-120 s compared to 30 s) and more ash-rich than those in 2012. We suggest that the reduced lava effusion rate in 2016 produced a net increase in the gas accumulation capacity of the shallow magma, and thus larger, less-frequent explosions. These findings indicate that gas permeability may be proportional to magma ascent and strain rate in dome-forming eruptions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008JVGR..177..578P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JVGR..177..578P"><span>Geology of the Side Crater of the Erebus volcano, Antarctica</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Panter, Kurt S.; Winter, Brian</p> <p>2008-11-01</p> <p>The summit cone of the Erebus volcano contains two craters. The Main crater is roughly circular (˜ 500 m diameter) and contains an active persistent phonolite lava lake ˜ 200 m below the summit rim. The Side Crater is adjacent to the southwestern rim of the Main Crater. It is a smaller spoon-shaped Crater (250-350 m diameter, 50-100 m deep) and is inactive. The floor of the Side Crater is covered by snow/ice, volcanic colluvium or weakly developed volcanic soil in geothermal areas (a.k.a. warm ground). But in several places the walls of the Side Crater provide extensive vertical exposure of rock which offers an insight into the recent eruptive history of Erebus. The deposits consist of lava flows with subordinate volcanoclastic lithologies. Four lithostratigraphic units are described: SC 1 is a compound lava with complex internal flow fabrics; SC 2 consists of interbedded vitric lavas, autoclastic and pyroclastic breccias; SC 3 is a thick sequence of thin lavas with minor autoclastic breccias; SC 4 is a pyroclastic fall deposit containing large scoriaceous lava bombs in a matrix composed primarily of juvenile lapilli-sized pyroclasts. Ash-sized pyroclasts from SC 4 consist of two morphologic types, spongy and blocky, indicating a mixed strombolian-phreatomagmatic origin. All of the deposits are phonolitic and contain anorthoclase feldspar. The stratigraphy and morphology of the Side Crater provides a record of recent volcanic activity at the Erebus volcano and is divided into four stages. Stage I is the building of the main summit cone and eruption of lavas (SC 1 and SC 3) from Main Crater vent(s). A secondary cone was built during Stage II by effusive and explosive activity (SC 2) from the Side Crater vent. A mixed strombolian and phreatomagmatic eruption (SC 4) delimits Stage III. The final stage (IV) represents a period of erosion and enlargement of the Side Crater.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.V34A..02F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.V34A..02F"><span>Infrasonic Observations of Explosions and Degassing at Kilauea Summit</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fee, D.; Garces, M.</p> <p>2008-12-01</p> <p>After 25 years of quiescence, eruptive activity returned to Kilauea Caldera with an explosion in Halema'uma'u crater on March 19th 2008. The explosion is presumed to be the clearing of a clogged vent. Along with the 3/19 explosion, at least 5 more gas-driven explosions have occurred and were clearly recorded at a 4-element infrasound array 7 km away. Acoustic energy estimates for these explosions yield energies between ~ 0.2-3 × 107 J. Infrasonic VLP energy is present for some of the explosions, but not all. The relatively long explosion durations (>20 seconds) and frequency content are consistent with a transient pressure pulse followed by the reverberation of a shallow gas chamber or conduit. Persistent degassing from Halema'uma'u followed the initial explosion. The harmonic infrasonic tremor produced by the degassing is the most energetic to date at Kilauea, with the cumulative tremor acoustic energy at ~107-108 Joules/hour. The complex tremor spectra show numerous peaks, with the dominant peak between 0.3-0.6 Hz and a smaller amplitude peak around 1-3 Hz. The peak frequency of the harmonic tremor has changed over time, which could be related to a change in the gas-filled chamber dimensions or temperature. Further analysis of the tremor spectra may help constrain dimensions. Consistent with our previous observations at Kilauea from Pu'u 'O'o, Fissure D, and lava skylights, the excitation of a gas within a confined volume appears to be the acoustic (and possibly seismic) source. For the tremor, we propose a mechanism where persistent degassing excites the gas volume into resonance. The explosions signals are consistent with a slug of gas reaching the free surface and exciting the conduit as well. Correlation of the infrasound signals with seismic tremor, LP and VLP signals suggest an open system connecting the atmosphere to the seismic excitation process at depth. Results will also be presented in relation to the recent observation of a visible lava lake within the conduit.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMNH13B1377S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMNH13B1377S"><span>Hazard maps of Colima volcano, Mexico</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Suarez-Plascencia, C.; Nunez-Cornu, F. J.; Escudero Ayala, C. R.</p> <p>2011-12-01</p> <p>Colima volcano, also known as Volcan de Fuego (19° 30.696 N, 103° 37.026 W), is located on the border between the states of Jalisco and Colima and is the most active volcano in Mexico. Began its current eruptive process in February 1991, in February 10, 1999 the biggest explosion since 1913 occurred at the summit dome. The activity during the 2001-2005 period was the most intense, but did not exceed VEI 3. The activity resulted in the formation of domes and their destruction after explosive events. The explosions originated eruptive columns, reaching attitudes between 4,500 and 9,000 m.a.s.l., further pyroclastic flows reaching distances up to 3.5 km from the crater. During the explosive events ash emissions were generated in all directions reaching distances up to 100 km, slightly affected nearby villages as Tuxpan, Tonila, Zapotlán, Cuauhtemoc, Comala, Zapotitlan de Vadillo and Toliman. During the 2005 this volcano has had an intense effusive-explosive activity, similar to the one that took place during the period of 1890 through 1900. Intense pre-plinian eruption in January 20, 1913, generated little economic losses in the lower parts of the volcano due to low population density and low socio-economic activities at the time. Shows the updating of the volcanic hazard maps published in 2001, where we identify whit SPOT satellite imagery and Google Earth, change in the land use on the slope of volcano, the expansion of the agricultural frontier on the east and southeast sides of the Colima volcano, the population inhabiting the area is approximately 517,000 people, and growing at an annual rate of 4.77%, also the region that has shown an increased in the vulnerability for the development of economic activities, supported by the construction of highways, natural gas pipelines and electrical infrastructure that connect to the Port of Manzanillo to Guadalajara city. The update the hazard maps are: a) Exclusion areas and moderate hazard for explosive events (rockfall) and pyroclastic flows, b) Hazard map of lahars and debris flow, and c) Hazard map of ash-fall. The cartographic and database information obtained will be the basis for updating the Operational Plan of the Colima Volcano by the State Civil & Fire Protection Unit of Jalisco, Mexico, and the urban development plans of surrounding municipalities, in order to reduce their vulnerability to the hazards of the volcanic activity.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss026e017074.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss026e017074.html"><span>Earth Observations taken by Expedition 26 crewmember</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2011-01-11</p> <p>ISS026-E-017074 (11 Jan. 2011) --- Emi Koussi volcano in Chad is featured in this image photographed by an Expedition 26 crew member on the International Space Station. The large Emi Koussi volcano is located in northern Chad at the southeastern end of the Tibesti Range. The dark volcanic rocks of the volcano provide a sharp contrast to the underlying tan and light brown sandstones exposed to the west, south, and east. Emi Koussi is a shield volcano formed from relatively low viscosity lavas—flowing more like motor oil as opposed to toothpaste—and explosively-erupted ignimbrites that produce a characteristic low and broad structure that covers a wide area (approximately 60 x 80 kilometers). This photograph highlights the entire volcanic structure; at 3,415 meters above sea level, Emi Koussi is the highest summit of the Sahara region. The summit area contains three calderas formed by powerful eruptions. Two older, and overlapping, calderas form a depression approximately 12 x 15 kilometers in area bounded by a distinct rim (center). According to scientists, the youngest and smallest caldera, Era Kohor, formed as a result of eruptive activity that occurred within the past 2 million years. Young volcanic features including lava flows and scoria cones are also thought to be less than 2 million years old. There are no historical records of eruptive activity at Emi Koussi, but there is an active thermal area on the southern flank of the volcano.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss014e18844.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss014e18844.html"><span>Earth Observations taken by the Expedition 14 crew</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2007-04-02</p> <p>ISS014-E-18844 (2 April 2007) --- A plume at Mt. Bagana, Bougainville Island is featured in this image photographed by an Expedition 14 crewmember on the International Space Station. Bougainville Island, part of the Solomon Islands chain to the east of Papua New Guinea, is typical of many Pacific Rim islands in that volcanism has played a large part in both its geological and recorded history. The island hosts three large volcanoes along its northwest-southeast trending axis: Mt. Balbi, Mt. Bagana, and the Mt. Takuan volcanic complex. Mt. Bagana (near center) is the only volcano on the island that has been historically active. Light green stressed vegetation, and brown lobate lava flows mark the 1,750 meter high lava cone of Mt. Bagana within the verdant landscape of Bougainville Island. The eruptive style of the volcano is typically non-explosive, producing thick lobes of andesitic lava that run down the flanks and maintain a dome in the summit crater. Occasional pyroclastic flows have also been noted. The most recent phase of activity, which began on March 7, has been characterized by vapor plumes with occasional ash-producing emissions. This photograph, acquired almost one month (twenty days) after the last reported activity at Bagana, records a diffuse white vapor plume extending west-southwest from the summit. The Solomon Island region experiences other effects due to the geologic setting: earlier this week, a large but shallow earthquake shook the region and induced a tsunami that hit the western part of the Solomon Island chain.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017E%26PSL.479..354S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017E%26PSL.479..354S"><span>Evaluating links between deformation, topography and surface temperature at volcanic domes: Results from a multi-sensor study at Volcán de Colima, Mexico</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Salzer, Jacqueline T.; Milillo, Pietro; Varley, Nick; Perissin, Daniele; Pantaleo, Michele; Walter, Thomas R.</p> <p>2017-12-01</p> <p>Dome building activity is common at many volcanoes and due to the gravitational instability, a dome represents one of the most hazardous volcanic phenomena. Shallow volcanic processes as well as rheological and structural changes of the dome affecting the fluid transport have been linked to transitions in eruptive activity. Also, hydrothermal alteration may affect the structural integrity of the dome, increasing the potential for collapse. However, mapping the deformation and details of fluid escape at the summit of steep sloped volcanoes and integrating these with other types of data is challenging due to difficult access and poor coverage. Here we present for the first time the near-vertical and near-horizontal surface deformation field of a quiescent summit dome and the relationships with degassing and topographic patterns. Our results are derived from high resolution satellite radar interferometry (InSAR) time series based on a year of TerraSAR-X SpotLight acquisitions and Structure from Motion (SfM) processing of overflight infrared data at Volcán de Colima, Mexico. The identified deformation is dominated by localized heterogeneous subsidence of the summit dome exceeding rates of 15 cm/yr, and strongly decreasing over the year 2012, up to the renewal of explosive and extrusive activity in early 2013. We tentatively attribute the deformation to the degassing, cooling and contraction of the dome and shallow conduit material. We also find that the results strongly differ depending on the chosen InSAR time series method, which potentially overprints the true physical complexities of small scale, shallow deformation processes. The combined interpretation of the deformation and infrared data reveals a complex spatial relationship between the degassing pathways and the deformation. While we observe no deformation across the crater rim fumaroles, discontinuities in the deformation field are more commonly observed around the dome rim fumaroles and occasionally on the dome upper surface. We propose that the deformation pattern is also linked to processes controlling the fumarole formation and distribution (topography, permeability and volcanic activity), and the lack of direct relationships may be explained by how the influence of these processes varies across the volcanic summit. The presented work provides a new approach for safely monitoring the activity and stability of internal dome structures, as well as for constraining and validating models of dome degassing pathways and densification processes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70171029','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70171029"><span>Seismo-acoustic signals associated with degassing explosions recorded at Shishaldin Volcano, Alaska, 2003-2004</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Petersen, T.</p> <p>2007-01-01</p> <p>In summer 2003, a Chaparral Model 2 microphone was deployed at Shishaldin Volcano, Aleutian Islands, Alaska. The pressure sensor was co-located with a short-period seismometer on the volcano’s north flank at a distance of 6.62 km from the active summit vent. The seismo-acoustic data exhibit a correlation between impulsive acoustic signals (1–2 Pa) and long-period (LP, 1–2 Hz) earthquakes. Since it last erupted in 1999, Shishaldin has been characterized by sustained seismicity consisting of many hundreds to two thousand LP events per day. The activity is accompanied by up to ∼200 m high discrete gas puffs exiting the small summit vent, but no significant eruptive activity has been confirmed. The acoustic waveforms possess similarity throughout the data set (July 2003–November 2004) indicating a repetitive source mechanism. The simplicity of the acoustic waveforms, the impulsive onsets with relatively short (∼10–20 s) gradually decaying codas and the waveform similarities suggest that the acoustic pulses are generated at the fluid–air interface within an open-vent system. SO2 measurements have revealed a low SO2 flux, suggesting a hydrothermal system with magmatic gases leaking through. This hypothesis is supported by the steady-state nature of Shishaldin’s volcanic system since 1999. Time delays between the seismic LP and infrasound onsets were acquired from a representative day of seismo-acoustic data. A simple model was used to estimate source depths. The short seismo-acoustic delay times have revealed that the seismic and acoustic sources are co-located at a depth of 240±200 m below the crater rim. This shallow depth is confirmed by resonance of the upper portion of the open conduit, which produces standing waves with f=0.3 Hz in the acoustic waveform codas. The infrasound data has allowed us to relate Shishaldin’s LP earthquakes to degassing explosions, created by gas volume ruptures from a fluid–air interface.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050214412','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050214412"><span>The Diversity of Martian Volcanic features as Seen in the MOC, THEMIS, and MOM Data Sets</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mouginis-Mark, Peter J.</p> <p>2005-01-01</p> <p>This one-year project (which included one-year no-cost tension) focused on the evolution of the summit areas of Martian volcanoes. It extended the studies conducted under an earlier MDAP project (Grant NAG5-9576, Principal Investigator P. Mouginis- Mark). By using data collected from the Mars Orbiter Camera (MOC), Thermal Emission Imaging System (THEMIS), and the Mars Orbiter Laser Altimeter (MOLA) instruments, we tried to better understand the diversity of constructional volcanism on Mars, and hence further understand the eruption processes. By inspecting THEMIS and MOC data, we explored the following four questions: (1) Where might near-surface volatiles have been released at the summits of the Tharsis volcanoes? Is the trapping and subsequent remobilization of degassed volatiles [Scott and Wilson, 19991 adequate to produce eruptions responsible for extensive deposits such as the ones identified on Arsia Mons [Mouginis-Mark, 2002]? To answer this question, we investigated the diversity of eruption styles by studying the summit areas of Arsia, Pavonis and Ascraeus Montes. (2) What are the geomorphic characteristics of the valley system on Hecates Tholus, a volcano that we have previously proposed experienced explosive activity [Mouginis-Murk et al., 1982]? Our inspection of THEMIS data suggests that water release on the volcano took place over an extended period of time, suggesting that hydrothermal activity may have taken place here. (3) How similar are the collapse processes observed at Martian and terrestrial calderas? New THEMIS data provide a more complete view of the entire Olympus Mons caldera, thereby enabling the comparison with the collapse features at Masaya volcano, Nicaragua, to be investigated. (4) What can we learn about the emplacement of long lava flows in the lava plains of Eastern Tharsis? The result of this work provided a greater understanding of the temporal and spatial variations in the eruptive history of volcanoes on Mars, and the influence of the volatiles within the top few kilometers of the volcanic edifice. This relationship in turn pertains to the availability of volatiles (both juvenile magmatic volatiles and ground water contained within the near-surface rocks) and to magma supply rates at appreciable distances (tens to hundreds of kilometers) from the centers of volcanoes. Explosive volcanism on Mars, a major factor in the release of water at the surface, may have been driven not only by volatiles within the parental melt, but also by magma encountering water or ice at shallow depth within the volcano [Mouginis-Mark et al., 1982, 1988; Crown and Greeley, 1993; Robinson et al., 19931.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_5 --> <div id="page_6" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="101"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70193252','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70193252"><span>Photogrammetric monitoring of lava dome growth during the 2009 eruption of Redoubt Volcano</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Diefenbach, Angela K.; Bull, Katharine F.; Wessels, Rick; McGimsey, Robert G.</p> <p>2013-01-01</p> <p>The 2009 eruption of Redoubt Volcano, Alaska, began with a phreatic explosion on 15 March followed by a series of at least 19 explosive events and growth and destruction of at least two, and likely three, lava domes between 22 March and 4 April. On 4 April explosive activity gave way to continuous lava effusion within the summit crater. We present an analysis of post-4 April lava dome growth using an oblique photogrammetry approach that provides a safe, rapid, and accurate means of measuring dome growth. Photogrammetric analyses of oblique digital images acquired during helicopter observation flights and fixed-wing volcanic gas surveys produced a series of digital elevation models (DEMs) of the lava dome from 16 April to 23 September. The DEMs were used to calculate estimates of volume and time-averaged extrusion rates and to quantify morphological changes during dome growth.Effusion rates ranged from a maximum of 35 m3 s− 1 during the initial two weeks to a low of 2.2 m3 s− 1 in early summer 2009. The average effusion rate from April to July was 9.5 m3 s− 1. Early, rapid dome growth was characterized by extrusion of blocky lava that spread laterally within the summit crater. In mid-to-late April the volume of the dome had reached 36 × 106 m3, roughly half of the total volume, and dome growth within the summit crater began to be limited by confining crater walls to the south, east, and west. Once the dome reached the steep, north-sloping gorge that breaches the crater, growth decreased to the south, but the dome continued to inflate and extend northward down the gorge. Effusion slowed during 16 April–1 May, but in early May the rate increased again. This rate increase was accompanied by a transition to exogenous dome growth. From mid-May to July the effusion rate consistently declined. The decrease is consistent with observations of reduced seismicity, gas emission, and thermal anomalies, as well as declining rates of geodetic deflation or inflation. These trends suggest dome growth ceased by July 2009. The volume of the dome at the end of the 2009 eruption was about 72 × 106 m3, more than twice the estimated volume of the largest dome extruded during the 1989–1990 eruption. In total, the 2009 dome extends over 400 m down the glacial gorge on the north end of the crater, with a total length of 1 km, width of 500 m and an average thickness of 200 m.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..1412231C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..1412231C"><span>Attaining high-resolution eruptive histories for active arc volcanoes with argon geochronology</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Calvert, A. T.</p> <p>2012-04-01</p> <p>Geochronology of active arc volcanoes commonly illuminates eruptive behavior over tens to hundreds of thousands of years, lengthy periods of repose punctuated by short eruptive episodes, and spatial and compositional changes with time. Despite the >1 Gyr half-life of 40K, argon geochronology is an exceptional tool for characterizing Pleistocene to Holocene eruptive histories and for placing constraints on models of eruptive behavior. Reliable 40Ar/39Ar ages of calc-alkaline arc rocks with rigorously derived errors small enough (± 500 to 3,000 years) to constrain eruptive histories are attainable using careful procedures. Sample selection and analytical work in concert with geologic mapping and stratigraphic studies are essential for determining reliable eruptive histories. Preparation, irradiation and spectrometric techniques have all been optimized to produce reliable, high-precision results. Examples of Cascade and Alaska/Aleutian eruptive histories illustrating duration of activity from single centers, eruptive episodicity, and spatial and compositional changes with time will be presented: (1) Mt. Shasta, the largest Cascade stratovolcano, has a 700,000-year history (Calvert and Christiansen, 2011 Fall AGU). A similar sized and composition volcano (Rainbow Mountain) on the Cascade axis was active 1200-950 ka. The eruptive center then jumped west 15 km to the south flank of the present Mt. Shasta and produced a stratovolcano from 700-450 ka likely rivaling today's Mt. Shasta. The NW portion of that edifice failed in an enormous (>30 km3) debris avalanche. Vents near today's active summit erupted 300-135 ka, then 60-15 ka. A voluminous, but short-lived eruptive sequence occurred at 11 ka, including a summit explosion producing a subplinian plume, followed by >60 km3 andesite-dacite Shastina domes and flows, then by the flank dacite Black Butte dome. Holocene domes and flows subsequently rebuilt the summit and flowed to the north and east. (2) Mt. Veniaminof on the Alaska Peninsula is a ~350 km3 tholeiitic arc volcano with basalt early in its history (~250 ka) and basaltic andesite to dacite currently. Chemical variation is due principally to crystallization differentiation with little or no evidence for crustal contamination. The smooth increase with time of Veniaminof's most silicic products chronicles the development of an intrusive complex, also reflected in granitoid blocks expelled during Holocene explosive eruptions (Bacon et al., 2007 Geology). (3) The Three Sisters in the central Oregon Cascades are a cluster of small volcanoes with remarkable chemical diversity (basalt to high silica rhyolite) that mainly erupted in a short interval between 40-15 ka. This eruptive interval was unusual in its chemical diversity beginning bimodal (basaltic andesite and rhyolite), progressing to dacite then andesite, and back to basaltic andesite. Over eighty percent of mapped units are dated, enabling time-series displays of the chemical and spatial evolution of the volcanic field (Calvert et al., 2010 Fall AGU).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMED51A0557D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMED51A0557D"><span>"IlVulcanoInforma": The restyling of the INGV Volcanological Information Centres, Aeolian Islands, Italy</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>D'Addezio, G.; Carapezza, M. L.; Riposati, D.; Team, L.</p> <p>2008-12-01</p> <p>Vulcano and Stromboli are the most active volcanoes of the Aeolian Islands. Vulcano is quiescent since the eruption of 1888-90 but in the last decades it experienced several crises with huge increase of gas output and temperature of the crater fumaroles, and variations in the magmatic gas components. Stromboli is characterized by a permanent mild explosive activity, episodically interrupted by major explosions, lava effusions, or paroxystic explosive events (October 2001: a tourist killed; December 2002: lava effusion, tsunami generated by flank collapse; April 2003: explosive paroxysm, block fallout on Ginostra village; February-March 2007: lava effusion and paroxysm). These islands are renowned tourist sites for the marvelous sea and the fascination that the volcanoes evoke. In fact, during summer risk increases as there are 10,000-15,000 persons per island (only a few hundreds in winter). Starting from the 1990 the INGV and the Civil Protection established a Volcanological Information Centre on each island with the main goal to inform population and tourists on the risks related to each volcano. During the year the two centres are visited by 8000-10,000 visitors coming from different countries. Researchers and trained students are involved in the educational activity devoted to inform visitors on the scientific aspects of volcano monitoring and hazard assessment and to ensure that tourists, willing to climb the summit crater area, will behave properly. In 2008 the Vulcano exhibition has been totally restyled. The INGV Laboratorio Grafica e Immagini has created for the project a composite and innovative graphic study. This includes a series of products (logos, brochures, panels ecc) with the intent to create new effective information means. The logo creation has been the first step for all the communications: an image with strong impact on volcano information distributed in strategic zones of the village to stimulate interest in the INGV centre and its exhibition.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMPA43C2202S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMPA43C2202S"><span>Don't Forget Kīlauea: Explosive Hazards at an Ocean Island Basaltic Volcano</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Swanson, D. A.; Houghton, B. F.</p> <p>2015-12-01</p> <p>Kīlauea alternates between periods of high and low magma supply rate, each period lasting centuries. The low rate is only a few percent of the high rate. High supply rate, typified by the past 200 years, leads to frequent lava flows, elevated SO2 emission, and relatively low-hazard Hawaiian-style explosive activity (lava fountains, spattering). Periods of low magma supply are very different. They accompany formation and maintenance of a deep caldera, the floor of which is at or below the water table, and are characterized by phreatomagmatic and phreatic explosive eruptions largely powered by external water. The low magma supply rate results in few lava flows and reduced SO2 output. Studies of explosive deposits from the past two periods of low magma supply (~200 BCE-1000 CE and ~1500-1800 CE) indicate that VEIs calculated from isopach maps can range up to a low 3. Clast-size studies suggest that subplinian column heights can reach >10 km (most recently in 1790), though more frequent column heights are ~5-8 km. Pyroclastic density currents (PDCs) present severe proximal hazards; a PDC in 1790 killed a few hundred people in an area of Hawaíi Volcanoes National Park today visited by 5000 people daily. Ash in columns less than about 5 km a.s.l. is confined to the trade-wind regime and advects southwest. Ash in higher columns enters the jet stream and is transported east and southeast of the summit caldera. Recurrence of such column heights today would present aviation hazards, which, for an isolated state dependent on air transport, could have especially deleterious economic impact. There is currently no way to estimate when a period of low magma supply, a deep caldera, and powerful explosive activity will return. Hazard assessments must take into account the cyclic nature of Kīlauea's eruptive activity, not just its present status; consequently, assessments for periods of high and low magma supply rates should be made in parallel to cover all eventualities.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70128562','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70128562"><span>Characterization of very-long-period seismicity accompanying summit activity at Kīlauea Volcano, Hawai'i: 2007-2013</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Dawson, Phillip; Chouet, Bernard</p> <p>2014-01-01</p> <p>Eruptive activity returned to the summit region of Kīlauea Volcano, Hawai'i with the formation of the “Overlook crater” within the Halema'uma'u Crater in March 2008. The new crater continued to grow through episodic collapse of the crater walls and as of late 2013 had grown into an approximately elliptical opening with dimensions of ~ 160 × 215 m extending to a depth of ~ 200 m. Occasional weak explosive events and a persistent gas plume continued to occur through 2013. Lava was first observed in the new crater in September 2008, and through 2009 the lava level remained deep in the crater and was only occasionally observed. Since early 2010 a lava lake with fluctuating level within the Overlook crater has been nearly continuously present, and has reached to within 22 m of the Overlook crater rim. Volcanic activity at Kīlauea Volcano is episodic at all time scales and the characterization of very-long-period seismicity in the band 2–100 s for the years 2007–2013 illuminates a portion of this broad spectrum of volcanic behavior. Three types of very-long-period events have been observed over this time and each is associated with distinct processes. Type 1 events are associated with vigorous degassing and occurred primarily between 2007 and 2009. Type 2 events are associated with rockfalls onto the lava lake and occurred primarily after early 2010. Both of these event types are induced by pressure and momentum changes at the top of the magma column that are transmitted downward to a source centroid ~ 1 km below the northeast corner of the Halema'uma'u Crater where the energy couples to the solid Earth at a geometrical discontinuity in the underlying dike system. Type 3 events are not related to surficial phenomena but are associated with transients in mass transfer that occur within the dike system. Very-long-period tremor has also accompanied the return of eruptive activity, with increasing amplitude associated with hours- to months-long changes in gas emission rates and summit deformation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA22156.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA22156.html"><span>Investigating Mars: Arsia Mons</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2018-01-02</p> <p>This THEMIS image shows part of the caldera floor of Arsia Mons. It is not uncommon for calderas to have "flat" floors after the final explosive eruption that empties the subsurface magma chamber. There may still be some magma or superheated rock left after the collapse that will fill in part of the depression. Additionally, over time erosion will work to level the topography. Within Arsia Mons there was renewed activity that occurred within the caldera along the alignment of the NE/SW trend of the three large volcanoes. This ongoing, low volume actitivity is similar to the lava lake in Kilauea in Hawaii. Small flows are visible throughout this image. Arsia Mons is the southernmost of the Tharsis volcanoes. It is 270 miles (450km) in diameter, almost 12 miles (20km) high, and the summit caldera is 72 miles (120km) wide. For comparison, the largest volcano on Earth is Mauna Loa. From its base on the sea floor, Mauna Loa measures only 6.3 miles high and 75 miles in diameter. A large volcanic crater known as a caldera is located at the summit of all of the Tharsis volcanoes. These calderas are produced by massive volcanic explosions and collapse. The Arsia Mons summit caldera is larger than many volcanoes on Earth. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 19588 Latitude: -9.19485 Longitude: 239.276 Instrument: VIS Captured: 2006-05-15 03:33 https://photojournal.jpl.nasa.gov/catalog/PIA22156</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995JVGR...69..217B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995JVGR...69..217B"><span>Chronology and dispersal characteristics of recently (last 5000 years) erupted tephra of Cotopaxi (Ecuador): implications for long-term eruptive forecasting</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barberi, F.; Coltelli, M.; Frullani, A.; Rosi, M.; Almeida, E.</p> <p>1995-12-01</p> <p>Cotopaxi, the highest active volcano on earth and one of the most dangerous of Ecuador is constituted by a composite cone made up of lava and tephra erupted from the summit crater. The activity of the present volcano begun with large-volume plinian eruptions followed by a succession of small-volume lava emissions and pyroclastic episodes which led to the edification of a symmetrical cone. The growth of the cone was broken by an episode of slope failure, the scar of which is now obliterated by recent and historical products. Volcanic history, eruptive frequency and characteristics of the activity were investigated by studying the stratigraphy of tephra and carrying out fifteen new 14C dating on paleosols and charcoals. The investigated period is comprised between the slope failure and the present. The deposit of the volcanic landside (dry debris avalanche of Rio Pita), previously believed to be between 13,000 and 25,000 yr B.P., is now considered to have an age slightly older than 5000 yr B.P. The stratigraphy of tephra of the last 2000 years reveals the existence of 22 fallout layers. Seven of them were dated with 14C whereas three were ascribed to the eruptions of 1534, 1768 and 1877 on the basis of comparison with historical information. Maximum clast size distribution (isopleths) of 9 tephra layers points out that the sustained explosive eruptions of Cotopaxi during the last 2000 years are characterized by very high dispersive power (plinian plumes with column heights between 28 and 39 km) and high intensity (peak mass discharges from 1.1 to 4.1 × 10 8kg/s). The magnitude (mass) of tephra fallout deposits calculated from distribution of thickness (isopaches) are, however, moderate (from 0.8 to 7.2 × 10 11 kg). The limited volume of magma erupted during each explosive episode is consistent with the lack of caldera collapses. Small-volume pyroclastic flows and surges virtually accompanied all identified tephra fallouts. During such an activity large scale snow/ice melting of the summit glacier produced devastating mudflows comparable in scale to those of 1877 eruption. By assuming a 1:1 correspondence between fallout episodes and generation of large-scale lahar, we have estimated an average recurrence of one explosive, lahartriggering event every 117 years over the last two millennia. This value compares well with that calculated by considering the period since Spanish Conquest. The probability of having an eruption like this in 100 or 200 years is respectively of 0.57 and 0.82. Such an high probability underscores the need for quick actions aimed at the mitigation of Cotopaxi lahar hazard along all the main valleys which originate from the volcano.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.bioone.org/doi/abs/10.1659/MRD-JOURNAL-D-09-00078.1','USGSPUBS'); return false;" href="http://www.bioone.org/doi/abs/10.1659/MRD-JOURNAL-D-09-00078.1"><span>Assessment and monitoring of recreation impacts and resource conditions on mountain summits: examples from the Northern Forest, USA</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Monz, Christopher A.; Marion, Jeffrey L.; Goonan, Kelly A.; Manning, Robert E.; Wimpey, Jeremy; Carr, Christopher</p> <p>2010-01-01</p> <p>Mountain summits present a unique challenge to manage sustainably: they are ecologically important and, in many circumstances, under high demand for recreation and tourism activities. This article presents recent advances in the assessment of resource conditions and visitor disturbance in mountain summit environments, by drawing on examples from a multiyear, interdisciplinary study of summits in the northeastern United States. Primary impact issues as a consequence of visitor use, such as informal trail formation, vegetation disturbance, and soil loss, were addressed via the adaption of protocols from recreation ecology studies to summit environments. In addition, new methodologies were developed that provide measurement sensitivity to change previously unavailable through standard recreation monitoring protocols. Although currently limited in application to the northeastern US summit environments, the methods presented show promise for widespread application wherever summits are in demand for visitor activities.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JSAES..79...12T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JSAES..79...12T"><span>The Quaternary history of effusive volcanism of the Nevado de Toluca area, Central Mexico</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Torres-Orozco, R.; Arce, J. L.; Layer, P. W.; Benowitz, J. A.</p> <p>2017-11-01</p> <p>Andesite and dacite lava flows and domes, and intermediate-mafic cones from the Nevado de Toluca area were classified into five groups using field data and 40Ar/39Ar geochronology constraints. Thirty-four lava units of diverse mineralogy and whole-rock major-element geochemistry, distributed between the groups, were identified. These effusive products were produced between ∼1.5 and ∼0.05 Ma, indicating a mid-Pleistocene older-age for Nevado de Toluca volcano, coexisting with explosive products that suggest a complex history for this volcano. A ∼0.96 Ma pyroclastic deposit attests for the co-existence of effusive and explosive episodes in the mid-Pleistocene history. Nevado de Toluca initiated as a composite volcano with multiple vents until ∼1.0 Ma, when the activity began to centralize in an area close to the present-day crater. The modern main edifice reached its maximum height at ca. 50 ka after bulky, spiny domes erupted in the current summit of the crater. Distribution and geochemical behavior in major elements of lavas indicate a co-magmatic relationship between different andesite and dacite domes and flows, although unrelated to the magmatism of the monogenetic volcanism. Mafic-intermediate magma likely replenished the system at Nevado de Toluca since ca. ∼1.0 Ma and contributed to the eruption of new domes, cones, as well as effusive-explosive activity. Altogether, field and laboratory data suggest that a large volume of magma was ejected around 1 Ma in and around the Nevado de Toluca.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993JVGR...59....1S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993JVGR...59....1S"><span>Major Holocene block-and-ash fan at the western slope of ice-capped Pico de Orizaba volcano, México: Implications for future hazards</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Siebe, Claus; Abrams, Michael; Sheridan, Michael F.</p> <p>1993-12-01</p> <p>A major block-and-ash fan extends more than 14 km westward from the summit of Pico de Orizaba volcano in the eastern part of the Trans-Mexican Volcanic Belt. Radiocarbon dating of charcoal within the fan deposits yielded Holocene ages that range between 4040 ± 80 and 4660 ± 100 y.B.P. Stratigraphical, sedimentological, geochemical, and scanning electron microscope studies indicate that this fan originated within a relatively short time-span by multiple volcanic explosions at the summit crater. This activity produced a series of pyroclastic flows (mainly block-and-ash flows) and lahars which were channelized by a glacial cirque and connecting U-shaped valleys as they descended toward the base of the volcano. A recurrence of a similar eruption today would pose severe hazards to the population of more than 50,000 people, who live in a potentially dangerous zone. A detailed reconstruction of the sequence of events that led to the formation of the block-and-ash fan is presented to help mitigate the risk. Special attention is given to the effects of an ice-cap and the role of pre-existing glacial morphology on the distribution of products from such an eruption.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2011/3145/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2011/3145/"><span>Newberry Volcano—Central Oregon's Sleeping Giant</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Donnelly-Nolan, Julie M.; Stovall, Wendy K.; Ramsey, David W.; Ewert, John W.; Jensen, Robert A.</p> <p>2011-01-01</p> <p>Hidden in plain sight, Oregon's massive Newberry Volcano is the largest volcano in the Cascades volcanic arc and covers an area the size of Rhode Island. Unlike familiar cone-shaped Cascades volcanoes, Newberry was built into the shape of a broad shield by repeated eruptions over 400,000 years. About 75,000 years ago a major explosion and collapse event created a large volcanic depression (caldera) at its summit. Newberry last erupted about 1,300 years ago, and present-day hot springs and geologically young lava flows indicate that it could reawaken at any time. Because of its proximity to nearby communities, frequency and size of past eruptions, and geologic youthfulness, U.S. Geological Survey scientists are working to better understand volcanic activity at Newberry and closely monitor the volcano for signs of unrest.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.V23C2840S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.V23C2840S"><span>The 2013 Eruptions of Pavlof and Mount Veniaminof Volcanoes, Alaska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schneider, D. J.; Waythomas, C. F.; Wallace, K.; Haney, M. M.; Fee, D.; Pavolonis, M. J.; Read, C.</p> <p>2013-12-01</p> <p>Pavlof Volcano and Mount Veniaminof on the Alaska Peninsula erupted during the summer of 2013 and were monitored by the Alaska Volcano Observatory (AVO) using seismic data, satellite and web camera images, a regional infrasound array and observer reports. An overview of the work of the entire AVO staff is presented here. The 2013 eruption of Pavlof Volcano began on May 13 after a brief and subtle period of precursory seismicity. Two volcano-tectonic (VT) earthquakes at depths of 6-8 km on April 24 preceded the onset of the eruption by 3 weeks. Given the low background seismicity at Pavlof, the VTs were likely linked to the ascent of magma. The onset of the eruption was marked by subtle pulsating tremor that coincided with elevated surface temperatures in satellite images. Activity during May and June was characterized by lava fountaining and effusion from a vent near the summit. Seismicity consisted of fluctuating tremor and numerous explosions that were detected on an infrasound array (450 km NE) and as ground-coupled airwaves at local and distant seismic stations (up to 650 km). Emissions of ash and sulfur dioxide were observed in satellite data extending as far as 300 km downwind at altitudes of 5-7 km above sea level. Ash collected in Sand Point (90 km E) were well sorted, 60-150 micron diameter juvenile glass shards, many of which had fluidal forms. Automated objective ash cloud detection and cloud height retrievals from the NOAA volcanic cloud alerting system were used to evaluate the hazard to aviation. A brief reconnaissance of Pavlof in July found that lava flows on the NW flank consist of rubbly, clast rich, 'a'a flows composed of angular blocks of agglutinate and rheomorphic lava. There are at least three overlapping flows, the longest of which extends about 5 km from the vent. Eruptive activity continued through early July, and has since paused or stopped. Historical eruptions of Mount Veniaminof volcano have been from an intracaldera cone within a 10-km summit caldera. Subtle pulsating tremor also signaled unrest at Veniaminof on June 7, a week prior to satellite observations of elevated surface temperatures within the caldera that indicated the presence of lava at the surface. Eruptive activity consisted of lava fountaining and effusion, and numerous explosive events that produced small ash clouds that typically reached only several hundred meters above the vent, and rarely were observed extending beyond the summit caldera. Seismicity was characterized by energetic tremor, and accompanied at times by numerous explosions that were heard by local residents at distances of 20-50 km, and detected as ground coupled airwaves at distant seismic stations (up to 200 km) and by an infrasound array (350 km distance). Because infrasound can propagate over great distances with little signal degradation or distortion, it was possible to correlate the ground-coupled airwaves between seismometers separated by 100's of km and thus identify their source. A helicopter fly over in July found that lava flows erupted from the intracaldera cone consist of 3-5 small lobes of rubbly spatter-rich lava up to 800 m in length on the southwest flank of the cone. The distal ends of the flows melted snow and ice adjacent to the cone to produce a water-rich plume, but there was no evidence for outflow of water from the caldera. Volcanic unrest has continued through early August, 2013.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70170377','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70170377"><span>Explosive eruptive record in the Katmai region, Alaska Peninsula: an overview</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Fierstein, Judy</p> <p>2007-01-01</p> <p>At least 15 explosive eruptions from the Katmai cluster of volcanoes and another nine from other volcanoes on the Alaska Peninsula are preserved as tephra layers in syn- and post-glacial (Last Glacial Maximum) loess and soil sections in Katmai National Park, AK. About 400 tephra samples from 150 measured sections have been collected between Kaguyak volcano and Mount Martin and from Shelikof Strait to Bristol Bay (∼8,500 km2 ). Five tephra layers are distinctive and widespread enough to be used as marker horizons in the Valley of Ten Thousand Smokes area, and 140 radiocarbon dates on enclosing soils have established a time framework for entire soil–tephra sections to 10 ka; the white rhyolitic ash from the 1912 plinian eruption of Novarupta caps almost all sections. Stratigraphy, distribution and tephra characteristics have been combined with microprobe analyses of glass and Fe– Ti oxide minerals to correlate ash layers with their source vents. Microprobe analyses (typically 20–50 analyses per glass or oxide sample) commonly show oxide compositions to be more definitive than glass in distinguishing one tephra from another; oxides from the Kaguyak caldera-forming event are so compositionally coherent that they have been used as internal standards throughout this study. Other than the Novarupta and Trident eruptions of the last century, the youngest locally derived tephra is associated with emplacement of the Snowy Mountain summit dome (<250 14C years B.P.). East Mageik has erupted most frequently during Holocene time with seven explosive events (9,400 to 2,400 14C years B.P.) preserved as tephra layers. Mount Martin erupted entirely during the Holocene, with lava coulees (>6 ka), two tephras (∼3,700 and ∼2,700 14C years B.P.), and a summit scoria cone with a crater still steaming today. Mount Katmai has three times produced very large explosive plinian to sub-plinian events (in 1912; 12– 16 ka; and 23 ka) and many smaller pyroclastic deposits show that explosive activity has long been common there. Mount Griggs, fumarolically active and moderately productive during postglacial time (mostly andesitic lavas), has three nested summit craters, two of which are on top of a Holocene central cone. Only one ash has been found that is (tentatively) correlated with the most recent eruptive activity on Griggs (<3,460 14C years B.P.). Eruptions from other volcanoes NE and SW beyond the Katmai cluster represented in this area include: (1) coignimbrite ash from Kaguyak’s caldera-forming event (5,800 14C years B.P.); (2) the climactic event from Fisher caldera (∼9,100 14C years B.P.—tentatively correlated); (3) at least three eruptions most likely from Mount Peulik (∼700, ∼7,700 and ∼8,500 14C years B.P.); and (4) a phreatic fallout most likely from the Gas Rocks (∼2,300 14C years B.P.). Most of the radiocarbon dating has been done on loess, soil and peat enclosing this tephra. Ash correlations supported by stratigraphy and microprobe data are combined with radiocarbon dating to show that variably organics-bearing substrates can provide reliable limiting ages for ash layers, especially when data for several sites is available.>(<3,460 14C years B.P.). Eruptions from other volcanoes NE and SW beyond the Katmai cluster represented in this area include: (1) coignimbrite ash from Kaguyak’s caldera-forming event (5,800 14C years B.P.); (2) the climactic event from Fisher caldera (∼9,100 14C years B.P.—tentatively correlated); (3) at least three eruptions most likely from Mount Peulik (∼700, ∼7,700 and ∼8,500 14C years B.P.); and (4) a phreatic fallout most likely from the Gas Rocks (∼2,300 14C years B.P.). Most of the radiocarbon dating has been done on loess, soil and peat enclosing this tephra. Ash correlations supported by stratigraphy and microprobe data are combined with radiocarbon dating to show that variably organics-bearing substrates can provide reliable limiting ages for ash layers, especially when data for several sites is available.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss034e027139.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss034e027139.html"><span>Earth Observations taken by Expedition 34 crewmember</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2013-01-10</p> <p>ISS034-E-027139 (10 Jan. 2013) --- Sakurajima Volcano in Kyushu, Japan is featured in this image photographed by an Expedition 34 crew member on the International Space Station. This photograph highlights Sakurajima, one of Japan’s most active volcanoes (center). There are several eruption craters near the 1,117 meter summit of Sakurajima; according to scientists, Kita-dake to the north last erupted approximately 5,000 years ago, while Minami-dake and Showa crater to the south have been the site of frequent eruptions since at least the 8th century. The ash plume visible near the volcano summit and extending to the southeast may have originated from either Minami-dake or Showa craters. Scientists believe that Sakurajima began forming approximately 13,000 years ago; prior to 1914, the volcano was an island in Kagoshima Bay—it was joined to the mainland by volcanic material following a major eruption in 1914. The image highlights the proximity of several large urban areas (Aira, Kagoshima, Kanoya, Kirishima, and Miyakonojo are readily visible) to Sakurajima. This has prompted studies of potential health hazards presented by the volcanic ash (Hillman et al. 2012), which are particularly important if more powerful explosive eruptive activity resumes at the volcano. The Tokyo Volcanic Ash Advisory Center (VAAC) of the Japan Meteorological Agency issues advisories when eruptions occur. An advisory on the activity captured in this image was issued less than one hour before the crew member took the photograph, by which time the plume tail had encountered northeast-trending upper-level winds (bottom center).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1710045I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1710045I"><span>Secular trends in plume composition of Erebus volcano, Antarctica</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ilanko, Tehnuka; Oppenheimer, Clive; Kyle, Philip; Burgisser, Alain</p> <p>2015-04-01</p> <p>Long-lived active lava lakes, such as that in the summit crater of Erebus volcano, Antarctica, provide a rare insight into sustained magma convection and degassing over long timescales. Erebus lava lake has been persistently active since 1972, and potentially for several decades or more previously (Ross, 1847). Since the 1970s, regular scientific expeditions, lasting a few weeks in the austral summers, have made observations of the lake activity. Annual Fourier transform infrared (FTIR) spectroscopic gas measurements began in 2004 (Oppenheimer and Kyle, 2008; Oppenheimer et al., 2009), yielding an extensive, if discontinuous, time series of infrared absorption spectra. These data, once processed, provide insights into temporal evolution of the gas geochemistry in terms of seven molecular species: H2O, CO2, CO, SO2, HCl, HF, and OCS. FTIR spectroscopic data are now available over ten field seasons, totalling roughly 1.8 million spectra and increasing each year. This period spans changes to crater morphology, fluctuations in lava lake surface area (Jones et al., 2014), and two episodes of increased explosive activity (2005-06 and 2013). The dataset captures both long-term degassing trends and short-lived features, such as cyclicity in gas emissions during passive degassing (Ilanko et al., 2015) and compositions released by explosive bubble-burst eruptions. We consider the longer-term changes to gas ratios occurring within (i.e. over days to weeks) and between annual field seasons, their potential causes, and their relationship to observations of eruptive behaviour and crater morphology.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss038e025895.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss038e025895.html"><span>Earth Observations taken by Expedition 38 crewmember</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2014-01-05</p> <p>ISS038-E-025895 (5 Jan. 2014) --- Bazman volcano in Iran is featured in this image photographed by an Expedition 38 crew member on the International Space Station. Bazman volcano is located in a remote southern region within the Bazman Protected Area of Sistan and Baluchestan Provinces. While the volcano has the classic cone shape associated with stratovolcanoes, it is also heavily dissected by channels that extend downwards from the 3,490-meter-above-sea-level summit. This radial drainage pattern - looking similar to the spokes of a bicycle wheel - is readily observed in this photograph. Such patterns can form around high, symmetric peaks when water runoff and erosion is not constrained by the resistance of geologic materials or barriers to flow, leading to essentially even distribution of water runoff channels around the central peak. While there is no historical record of volcanism at Bazman, and no geologic record of eruptive activity within the past 10,000 years, some fumarolic activity - gas and steam emissions - have been reported, according to the Smithsonian Institution National Museum of Natural History's Global Volcanism Program. The summit of the volcano is marked by a well-formed explosion crater, and lava cones formed on the flanks of the main volcano are associated with well-preserved lava flows-a particularly striking example is visible on the north flank of Bazman at center. Together, these observations and features are suggestive that Bazman may be a dormant, rather than extinct, volcano.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUSM.V44A..06V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUSM.V44A..06V"><span>Eruptive mechanism at Volcán de Colima: Interpreting transitions between styles</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Varley, N.; James, M. R.; Hutchison, W.; Arámbula, R.; Reyes, G.</p> <p>2013-05-01</p> <p>In January 2013 eruptions resumed at Volcán de Colima, the previous activity having ceased in June 2011. This period represented the quietest the volcano has been since before the previous episode commenced in 1998. The new eruptive episode is showing differences compared to the 1998-2011 period, which are presenting a challenge to interpret. Lower gases fluxes coupled with lower fumaroles temperatures are consistent with the decreasing trend of volatile-contents but the two larger Vulcanian eruptions in January produced pyroclastic density currents with a greater degree of fragmentation than previous events. A dome has been growing within the newly formed crater within the previous dome. The 1998-2011 eruption included five periods of effusive activity, with little variation in composition. Domes grew with effusion rates covering more than 2 orders of magnitude. Both explosive and effusive activity was centred at multiple locations within the summit crater. The SO2 flux showed a general declining trend throughout this period and 2005 included the largest pyroclastic flows witnessed since the last Plinian eruption in 1913. Swarms of small amplitude long period events were detected prior to each larger eruption, these have been again witnessed in 2013. The characteristics of the swarms is being compared, the generation of events being related to brittle fracturing along the conduit margin. The episode terminated in June 2011 with an explosion which removed the upper portion of the most recent and extended period of dome growth, which was at a very slow rate from January 2007. Automated 3D computer vision reconstruction techniques (structure-from-motion and multi-view stereo, SfM-MVS) have permitted the estimation of dome volumes from 1 m resolution digital elevation models. A small decrease in volume (0.4×105 m3) was detected prior to the explosion, which was related to the formation of steps in the dome surface, related to localized zones of weakness. For the explosion, the region of greatest volume loss was observed to be not coincident with the assumed location of the conduit, suggesting and that heterogeneity within the dome was important during the June explosion. Analysis of thermal images taken during flights has permitted the detailed modelling of the dome emplacement processes. The onset of rockfalls on the W side once it reached the crater rim provoked a change in emplacement style from endogenic to exogenic. Monitoring the activity during the recent eruption has produced a wealth of data making it an excellent case study for modelling transitions between different regimes and the generating mechanism for Vulcanian explosions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70013821','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70013821"><span>Detailed record of SO2 emissions from Pu'u `O`o between episodes 33 and 34 of the 1983-86 ERZ eruption, Kilauea, Hawaii</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Chartier, T.A.; Rose, William I.; Stokes, J.B.</p> <p>1988-01-01</p> <p>A tripod-mounted correlation spectrometer was used to measure SO2 emissions from Pu`u `O`o vent, mid-ERZ, Kilauea, Hawaii between Episodes 33 and 34 (June 13 to July 6, 1985). In 24 repose days, 906 measurements were collected, averaging 38 determinations/day. Measurements reflect 13% of the total 576 hours of the repose and 42% of the bright daylight hours. The average SO2 emission for the 24-day repose interval is 167??83 t/d, a total of 4000 tonnes emitted for the entire repose. The large standard deviation reflects the "puffing" character of the plume. The overall rate of SO2 degassing gently decreased with a zero-intercept of 44-58 days and was interrupted by two positive peaks. The data are consistent with the gas emanating from a cylindrical conduit of 50 meter diameter and a length of 1700 meters which degasses about 50% of its SO2 during 24 days. This is in support of the Pu'u `O`o model of Greenland et al. (1987). 36 hours before the onset of Episode 34 (July 5-6, 1985), elevated SO2 emissions were detected while the magma column was extremely active ultimately spilling over during dome fountaining. A "mid-repose" anomaly of SO2 emission (June 21-22, 1985) occurs two days before a sudden increase in the rate of summit inflation (on June 24, 1985), suggesting magma was simultaneously being injected in both the ERZ and summit reservoir until July 24 when it was channelled only to the summit reservoir. This implies degassing magma is sensitive to perturbations within the rift zone conduit system and may at times reflect these disturbances. Periods of 7-45 min are detected in the daily SO2 emissions, which possibly reflect timing of convective overturn in the cylindrical magma body. If the 33-34 repose interval is considered representative of other repose periods, the ERZ reposes of Jan 1983-Jan 1986 ERZ activity, contributed 1.6 ?? 105 tonnes of SO2 to the atmosphere. Including summit fuming from non-eruptive fumaroles (2.7 ?? 105 tonnes SO2); 28% of the total SO2 budget from Kilauea between Jan 1983 to Jan 1986 was contributed by quiescent degassing, and the remainder was released during explosive fountaining episodes. ?? 1988 Springer-Verlag.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70142775','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70142775"><span>Keeping watch over Colombia’s slumbering volcanoes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ordoñez, Milton; López, Christian; Alpala, Jorge; Narváez, Lourdes; Arcos, Dario; Battaglia, Maurizio</p> <p>2015-01-01</p> <p>Located in the Central Cordillera (Colombian Andes), Nevado del Ruiz is a volcanic complex, topped by glaciers, rising 5,321 m above sea level. A relatively small explosive eruption from Ruiz's summit crater on November 13, 1985, generated an eruption column and sent a series of pyroclastic flows and surges across the volcano's ice-covered summit. Pumice and meltwater produced by the hot pyroclastic flows and surges swept into gullies and channels on the slopes of Ruiz as a series of lahars. Within two hours of the beginning of the eruption, lahars had traveled 100 km and left behind a wake of destruction: more than 25,000 people were killed (23,000 in the town of Armero and 2,000 in the town of Chinchiná), about 5,000 injured, and more than 5,000 homes destroyed along the Chinchiná, Gualí, and Lagunillas rivers.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://ngmdb.usgs.gov/Prodesc/proddesc_68269.htm','USGSPUBS'); return false;" href="http://ngmdb.usgs.gov/Prodesc/proddesc_68269.htm"><span>Geology of the Ugashik-Mount Peulik Volcanic Center, Alaska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Miller, Thomas P.</p> <p>2004-01-01</p> <p>The Ugashik-Mount Peulik volcanic center, 550 km southwest of Anchorage on the Alaska Peninsula, consists of the late Quaternary 5-km-wide Ugashik caldera and the stratovolcano Mount Peulik built on the north flank of Ugashik. The center has been the site of explosive volcanism including a caldera-forming eruption and post-caldera dome-destructive activity. Mount Peulik has been formed entirely in Holocene time and erupted in 1814 and 1845. A large lava dome occupies the summit crater, which is breached to the west. A smaller dome is perched high on the southeast flank of the cone. Pyroclastic-flow deposits form aprons below both domes. One or more sector-collapse events occurred early in the formation of Mount Peulik volcano resulting in a large area of debris-avalanche deposits on the volcano's northwest flank. The Ugashik-Mount Peulik center is a calcalkaline suite of basalt, andesite, dacite, and rhyolite, ranging in SiO2 content from 51 to 72 percent. The Ugashik-Mount Peulik magmas appear to be co-genetic in a broad sense and their compositional variation has probably resulted from a combination of fractional crystallization and magma-mixing. The most likely scenario for a future eruption is that one or more of the summit domes on Mount Peulik are destroyed as new magma rises to the surface. Debris avalanches and pyroclastic flows may then move down the west and, less likely, east flanks of the volcano for distances of 10 km or more. A new lava dome or series of domes would be expected to form either during or within some few years after the explosive disruption of the previous dome. This cycle of dome disruption, pyroclastic flow generation, and new dome formation could be repeated several times in a single eruption. The volcano poses little direct threat to human population as the area is sparsely populated. The most serious hazard is the effect of airborne volcanic ash on aircraft since Mount Peulik sits astride heavily traveled air routes connecting the U.S. and Europe to Asia. Activity of the type described could produce eruption columns to heights of 15 km and result in significant amounts of ash 250-300 km downwind.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_6 --> <div id="page_7" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="121"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011GeoRL..38.6308M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011GeoRL..38.6308M"><span>Long-range acoustic observations of the Eyjafjallajökull eruption, Iceland, April-May 2010</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Matoza, Robin S.; Vergoz, Julien; Le Pichon, Alexis; Ceranna, Lars; Green, David N.; Evers, Läslo G.; Ripepe, Maurizio; Campus, Paola; Liszka, Ludwik; Kvaerna, Tormod; Kjartansson, Einar; Höskuldsson, Ármann</p> <p>2011-03-01</p> <p>The April-May 2010 summit eruption of Eyjafjallajökull, Iceland, was recorded by 14 atmospheric infrasound sensor arrays at ranges between 1,700 and 3,700 km, indicating that infrasound from modest-size eruptions can propagate for thousands of kilometers in atmospheric waveguides. Although variations in both atmospheric propagation conditions and background noise levels at the sensors generate fluctuations in signal-to-noise ratios and signal detectability, array processing techniques successfully discriminate between volcanic infrasound and ambient coherent and incoherent noise. The current global infrasound network is significantly more dense and sensitive than any previously operated network and signals from large volcanic explosions are routinely recorded. Because volcanic infrasound is generated during the explosive release of fluid into the atmosphere, it is a strong indicator that an eruption has occurred. Therefore, long-range infrasonic monitoring may aid volcanic explosion detection by complementing other monitoring technologies, especially in remote regions with sparse ground-based instrument networks.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70011374','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70011374"><span>Thermal areas on Kilauea and Mauna Loa Volcanoes, Hawaii</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Casadevall, Thomas J.; Hazlett, Richard W.</p> <p>1983-01-01</p> <p>Active thermal areas are concentrated in three areas on Mauna Loa and three areas on Kilauea. High-temperature fumaroles (115-362°C) on Mauna Loa are restricted to the summit caldera, whereas high-temperature fumaroles on Kilauea are found in the upper East Rift Zone (Mauna Ulu summit fumaroles, 562°C), middle East Rift Zone (1977 eruptive fissure fumaroles), and in the summit caldera. Solfataric activity that has continued for several decades occurs along border faults of Kilauea caldera and at Sulphur Cone on the southwest rift zone of Mauna Loa. Solfataras that are only a few years old occur along recently active eruptive fissures in the summit caldera and along the rift zones of Kilauea. Steam vents and hot-air cracks also occur at the edges of cooling lava ponds, on the summits of lava shields, along faults and graben fractures, and in diffuse patches that may reflect shallow magmatic intrusions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EP%26S...68...72K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EP%26S...68...72K"><span>2014 Mount Ontake eruption: characteristics of the phreatic eruption as inferred from aerial observations</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kaneko, Takayuki; Maeno, Fukashi; Nakada, Setsuya</p> <p>2016-05-01</p> <p>The sudden eruption of Mount Ontake on September 27, 2014, led to a tragedy that caused more than 60 fatalities including missing persons. In order to mitigate the potential risks posed by similar volcano-related disasters, it is vital to have a clear understanding of the activity status and progression of eruptions. Because the erupted material was largely disturbed while access was strictly prohibited for a month, we analyzed the aerial photographs taken on September 28. The results showed that there were three large vents in the bottom of the Jigokudani valley on September 28. The vent in the center was considered to have been the main vent involved in the eruption, and the vents on either side were considered to have been formed by non-explosive processes. The pyroclastic flows extended approximately 2.5 km along the valley at an average speed of 32 km/h. The absence of burned or fallen trees in this area indicated that the temperatures and destructive forces associated with the pyroclastic flow were both low. The distribution of ballistics was categorized into four zones based on the number of impact craters per unit area, and the furthest impact crater was located 950 m from the vents. Based on ballistic models, the maximum initial velocity of the ejecta was estimated to be 111 m/s. Just after the beginning of the eruption, very few ballistic ejecta had arrived at the summit, even though the eruption plume had risen above the summit, which suggested that a large amount of ballistic ejecta was expelled from the volcano several tens-of-seconds after the beginning of the eruption. This initial period was characterized by the escape of a vapor phase from the vents, which then caused the explosive eruption phase that generated large amounts of ballistic ejecta via sudden decompression of a hydrothermal reservoir.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JVGR..357..239A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JVGR..357..239A"><span>Combination of a pressure source and block movement for ground deformation analysis at Merapi volcano prior to the eruptions in 2006 and 2010</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aisyah, Nurnaning; Iguchi, Masato; Subandriyo; Budisantoso, Agus; Hotta, Kohei; Sumarti, Sri</p> <p>2018-05-01</p> <p>We analyzed ground deformation prior to the eruptions in 2006 and 2010 at Merapi volcano, Central Java, Indonesia. Ground deformation was monitored by electronic distance measurement (EDM) by measuring the slope distance toward 12 reflectors installed near the summit from five benchmarks on flanks every day. A large change of slope distance (CSD) was detected on the southeast and south baselines and a minor CSD was detected on the north and northwest baselines during the pre-eruptive stages of both the 2006 and 2010 eruptions. We applied a block movement model to the south and southeast baselines and a spherical pressure source model to the CSDs on the north and northwest baselines using the finite element method (FEM). The rates of block movement southward and the volume change of the pressure source increased on April 7, 2006 and continued at constant rates until the appearance of a new lava dome on April 26. Prior to the eruption in 2010, the block movement southeastward and the volume increase of the pressure source accelerated in the middle of October, and acceleration continued until the first outburst on October 26, 2010. Temporal patterns of the block movement and the increase in the volume of the pressure source correlate well with the increase in seismicity of VT and MP earthquakes. The pressure sources were obtained at a depth of 2 ± 0.5 km below the summit, and this position corresponds to the aseismic zone of VT earthquakes. Magma injection at the shallow part of this region causes an increase in the volume of the pressure source, and inflation of the ground of the summit triggered gravitational slip southeastward or southward of the ground surface. The volumes increases of the pressure sources were 9.7 ± 1 M m3 and 17.6 ± 0.8 M m3 in 2006 and 2010, respectively. The volume increase is related to the scale and type of the eruption. The effusive eruption in 2006 had a volcanic explosivity index (VEI) of 2 and the explosive eruption in 2010 had a VEI of 4. The directions and amounts of the block movement are strongly related to topography, hydrothermally weak zone and underground gap near the summit between West and East Domes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70154994','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70154994"><span>High-resolution satellite and airborne thermal infrared imaging of precursory unrest and 2009 eruption of Redoubt Volcano, Alaska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wessels, Rick L.; Vaughan, R. Greg; Patrick, Matthew R.; Coombs, Michelle L.</p> <p>2013-01-01</p> <p>A combination of satellite and airborne high-resolution visible and thermal infrared (TIR) image data detected and measured changes at Redoubt Volcano during the 2008–2009 unrest and eruption. The TIR sensors detected persistent elevated temperatures at summit ice-melt holes as seismicity and gas emissions increased in late 2008 to March 2009. A phreatic explosion on 15 March was followed by more than 19 magmatic explosive events from 23 March to 4 April that produced high-altitude ash clouds and large lahars. Two (or three) lava domes extruded and were destroyed between 23 March and 4 April. After 4 April, the eruption extruded a large lava dome that continued to grow until at least early July 2009.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.V11C2057M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.V11C2057M"><span>Subaqueous non-vesicular to poorly-vesicular shards: hydroclastic fragmentation on seamounts and summit calderas</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mueller, W. U.; Dingwell, D. B.; Downey, W. S.; Mastin, L. G.</p> <p>2008-12-01</p> <p>Recognizing pyroclastic deposits that originate directly from magmatic and phreatomagmatic explosions in a subaqueous setting is based upon sedimentary structures, such as massive, stratified, and graded beds as well as (pyro)clast size. Ideally such deposits form ordered fining-and thinning-upward sequences. Pumice, scoria, glass shards, euhedral and broken crystals, and lithic fragments are constituents that support an explosive heritage. Recent deep-sea ROV and submersible dives have retrieved non-vesicular to vesicle- poor, mm-scale, mafic shards in 5-15 cm-thick massive and/or graded (stratified) deposits, for which a subaqueous explosive origin has been inferred. These sheet hyaloclastites with variable shard shapes were first documented on Seamount 6 as deep-sea Limu O Pele at water depths > 1000 m. We identified in Seamount 6 samples equant to blocky shards with angular to subrounded terminations, but also subordinate hair-like and contorted glassy filaments, warped shards and irregular shards. Shards display internal laminations (flow-banding?) and have local perlitic fractures. Bubble wall shards derived from scoria burst were rare. In combination with all the above and a poor shard vesicularity (< 2%), a magmatic explosive origin seems improbable. Such small-volume deposits have been reported from seamounts and summit calderas associated with subaqueous drainage tubes and ponded magma in depths > 1000 m. We envision that hydrostatic pressure commensurate with water depth played a significant role. The deposits can be readily explained by a hydroclastic process whereby fragmentation occurred at the milli-second (Limu) to second scale (hyaloclastite). Hence, hyperquenched glass shards or thread-like glass filaments need not require magmatic explosivity. Constant surface interaction between aphyric, low-viscosity, high temperature, magma-lava at depth with seawater causes fragmentation (granulation) that can generate such delicate shards. The transfer of heat to the ambient medium, seawater, favours turbulent convection causing strong water movement that strips glassy rinds and lofts the fine-grained shards and Limu O Pele into the water column. Once entrained, shards are deposited after water turbulence abates. Congestion of the water column causes deposition from low-density turbidity currents and subaqueous fallout. In this manner delicate textures would remain intact even if removed from the site of hydroclastic fragmentation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED402233.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED402233.pdf"><span>Youth Summits: Youth and Adults as Partners in Violence Prevention. Technical Assistance Bulletin, No. 14.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Perry, George S., Jr.</p> <p></p> <p>Taking the position that Youth for Justice Youth Summits were highly successful in their inaugural year of 1995, this report explains the purpose and goals of the summits. The report also summarizes the activities undertaken in the 47 states (plus the District of Columbia and Puerto Rico) where the summits were held on a state-by-state basis. The…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss011e08489.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss011e08489.html"><span>Earth Obsersation taken by the Expedition 11 crew</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2005-06-10</p> <p>ISS011-E--8489 (10 June 2005) --- This digital still photograph, taken on June 10 from the Earth-orbiting International Space Station, shows an active Colima, the most prominent volcanic center of the western Mexican Belt. Around 11 p.m. local time, June 6, an explosion from this volcano, for which the summit elevation is approximately 3,850 meters, produced an ash plume to a height of approximately 8.5 kilometers (27,900 feet). The ash plume traveled southwest at a speed of approximately 79 kilometers per hour, and ash fell in and around the cities of Colima, about 30 kilometers away, and Villa de Alvarez. Brief evacuation of some 50 residents in the area was considered a minor undertaking and it was reported some three days after this picture was taken that all were able to return to their homes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss011e08490.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss011e08490.html"><span>Earth Obsersation taken by the Expedition 11 crew</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2005-06-10</p> <p>ISS011-E--8490 (10 June 2005) --- This digital still photograph, taken on June 10 from the Earth-orbiting International Space Station, shows an active Colima, the most prominent volcanic center of the western Mexican Belt. Around 11 p.m. local time, June 6, an explosion from this volcano, for which the summit elevation is approximately 3,850 meters, produced an ash plume to a height of approximately 8.5 kilometers (27,900 feet). The ash plume traveled southwest at a speed of approximately 79 kilometers per hour, and ash fell in and around the cities of Colima, about 30 kilometers away, and Villa de Alvarez. Brief evacuation of some 50 residents in the area was considered a minor undertaking and it was reported some three days after this picture was taken that all were able to return to their homes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.C11C0931H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.C11C0931H"><span>Impacts and societal benefits of research activities at Summit Station, Greenland</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hawley, R. L.; Burkhart, J. F.; Courville, Z.; Dibb, J. E.; Koenig, L.; Vaughn, B. H.</p> <p>2017-12-01</p> <p>Summit Station began as the site for the Greenland Ice Sheet Project 2 ice core in 1989. Since then, it has hosted both summer campaign science, and since 1997, year-round observations of atmospheric and cryospheric processes. The station has been continuously occupied since 2003. While most of the science activities at the station are supported by the US NSF Office of Polar Programs, the station also hosts many interagency and international investigations in physical glaciology, atmospheric chemistry, satellite validation, astrophysics and other disciplines. Summit is the only high elevation observatory north of the Arctic circle that can provide clean air or snow sites. The station is part of the INTER-ACT consortium of Arctic research stations with the main objective to identify, understand, predict and respond to diverse environmental changes, and part of the International Arctic Systems for Observing the Atmosphere (IASOA) that coordinates Arctic research activities and provides a networked, observations-based view of the Arctic. The Summit Station Science Summit, sponsored by NSF, assembled a multidisciplinary group of scientists to review Summit Station science, define the leading research questions for Summit, and make community-based recommendations for future science goals and governance for Summit. The impact of several on-going observation records was summarized in the report "Sustaining the Science Impact of Summit Station, Greenland," including the use of station data in weather forecasts and climate models. Observations made at the station as part of long-term, year-round research or during shorter summer-only campaign seasons contribute to several of the identified Social Benefit Areas (SBAs) outlined in the International Arctic Observations Assessment Framework published by the IDA Science and Technology Policy Institute and Sustaining Arctic Observing Networks as an outcome of the 2016 Arctic Science Ministerial. The SBAs supported by research conducted at Summit include Fundamental Understanding of Arctic Systems, Infrastructure and Operations, Terrestrial and Freshwater Ecosystems and Processes and Weather and Climate. Future efforts at maintaining the station's long-term climate record will focus on these areas, as identified in the Summit Station Science Summit report.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18..842H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18..842H"><span>Mechanical constraints on the triggering of vulcanian explosions at Santiaguito volcano, Guatemala</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hornby, Adrian; Lavallée, Yan; Collinson, Amy; Neuberg, Jurgen; De Angelis, Silvio; Kendrick, Jackie; Lamur, Anthony</p> <p>2016-04-01</p> <p>Gas- and ash explosions at Santiaguito volcano occur at regular 20-200 minute intervals, exiting through arcuate fractures in the summit dome of the Caliente vent. Infrasound, ground deformation and seismic monitoring collected during a long term monitoring survey conducted by the University of Liverpool have constrained a stable, repeatable source for these explosions. The explosions maintain similar magnitudes and (low) erupted mass throughout examined period. Ground deformation reveals stable ~25 minute inflation-deflation cycles, which culminate in either explosions or passive outgassing. Inversion of infrasound sources has revealed that faster inflation rates during the final minutes before peak inflation lead to explosions. These explosions fragment a consistently small-volume pressurized, gas-rich domain within magma located below a denser, lower permeability magma plug. Rapid decompression of this gas-rich domain occurs through fracturing and faulting, creating a highly permeable connection with atmospheric pressures near to the dome surface. We surmise that the dominant fracture mode at these shallow depths is tensile due to the volumetric strain exerted by a pressurising source below the magma plug, however a component of shear is also detected during explosive events. Fractures may either propagate downwards from the dome surface (due to greater magma stiffness and lower confining pressure) or upwards from the gas-rich domain (due to higher strain rates at the deformation source in the case of viscous deformation). In order to constrain the origin and evolution of these fractures we have conducted Brazilian tensile stress tests on lavas from the Caliente vent at strain rates from 10-3-10-5, porosities 3-30% and temperatures 20-800 °C. Across the expected conduit temperature range (750-800 °C) the dome material becomes highly sensitive to strain rate, showing a range of response from elastic failure to viscous flow. The total strain accommodated prior to failure shows a non-linear increase as viscous deformation becomes more important (i.e. temperature is increased or strain rate decreased). This allows us to constrain timescales for fracture propagation for given temperature-strain rate scenarios. We use these results, together with monitoring data and the results of numerical modelling to compare the probability of fractures propagating from the top-down or bottom-up prior to explosions at Santiaguito. Thus, we shed light on the triggers and signals leading to vulcanian explosions, which may be widely applicable to vulcanian explosions at active volcanoes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004EOSTr..85...97A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004EOSTr..85...97A"><span>Real-Time Data Received from Mount Erebus Volcano, Antarctica</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aster, Richard; McIntosh, William; Kyle, Philip; Esser, Richard; Bartel, Beth Ann; Dunbar, Nelia; Johns, Bjorn; Johnson, Jeffrey B.; Karstens, Richard; Kurnik, Chuck; McGowan, Murray; McNamara, Sara; Meertens, Chuck; Pauley, Bruce; Richmond, Matt; Ruiz, Mario</p> <p>2004-03-01</p> <p>Internal and eruptive volcano processes involve complex interactions of multi-phase fluids with the solid Earth and the atmosphere, and produce diverse geochemical, visible, thermal, elastic, and anelastic effects. Multidisciplinary experimental agendas are increasingly being employed to meet the challenge of understanding active volcanoes and their hazards [e.g., Ripepe et al., 2002; Wallace et al., 2003]. Mount Erebus is a large (3794 m) stratovolcano that forms the centerpiece of Ross Island, Antarctica, the site of the principal U.S. (McMurdo) and New Zealand (Scott) Antarctic bases. With an elevation of 3794 m and a volume of ~1670 km3, Erebus offers exceptional opportunities for extended study of volcano processes because of its persistent, low-level, strombolian activity (Volcano Explosivity Index 0-1) and exposed summit magma reservoir (manifested as a long-lived phonolitic lava lake). Key scientific questions include linking conduit processes to near-field deformations [e.g., Aster et al., 2003], explosion physics [e.g., Johnson et al., 2003], magmatic differentiation and residence [e.g., Kyle et al., 1992], and effects on Antarctic atmospheric and ice geochemistry [e.g., Zreda-Gostynska et al., 1997]. The close proximity of Erebus (35 km) to McMurdo, and its characteristic dry, windy, cold, and high-elevation Antarctic environment, make the volcano a convenient test bed for the general development of volcano surveillance and other instrumentation under extreme conditions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19489519','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19489519"><span>Can summits lead to curricula change? An evaluation of emergency preparedness summits for schools of nursing in Georgia.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Buyum, Arielle; Dubruiel, Nicole; Torghele, Karen; Alperin, Melissa; Miner, Kathleen R</p> <p>2009-05-01</p> <p>The Emory University Center for Public Health Preparedness held two summits for nurses that were evaluated by survey. Participants cited multiple deficiencies and challenges with integrating emergency preparedness into nursing curricula. The summits and the related materials were reported as highly useful by survey respondents. More than three fourths of respondents reported incorporating emergency preparedness education into their curricula after summit attendance. Nursing professionals could use summits to encourage active practitioners to pursue continuing education and to initiate efforts to incorporate emergency preparedness and related health care issues into the curricula of schools of nursing.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.V41A2480G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.V41A2480G"><span>Geochemistry of glass and olivine from Keanakako`i Tephra at Kilauea Volcano, Hawai`i</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Garcia, M. O.; Mucek, A. E.; Swanson, D.</p> <p>2011-12-01</p> <p>Kilauea Volcano is well known for its frequent quiescent eruptions. However, it also has an underappreciated explosive past. Recent field work has documented many details of the Keanakako`i Tephra, which was generated during a period of explosive activity when few lava flows were erupted. The dominantly phreatomagmatic eruptions, which produced the Keanakako`i Tephra, began late in, or completely after, the formation of Kilauea Caldera (ca. 1500 CE) and continued sporadically until 1823. Thereafter, effusive eruptions outside the caldera resumed and have continued to the present.The Keanakako`i deposits provide an opportunity to examine the restoration of Kilauea's magmatic plumbing following caldera formation. Glassy products with variable amounts of olivine dominate from ca. 1500 A.D. to the late 1600 A.D., whereas lithic-rich deposits with sparse glass are common in the 1700 A.D. deposits, which include the deadly explosive activity of A.D. 1790. Glass compositions from tephra and basalt flows show remarkable MgO variations (4-11 wt percent), larger than those observed in glasses from subsequent eruptions. Some units have variable MgO indicating a zoned magma reservoir, whereas some others have variable incompatible element ratios suggesting magma mixing. The highest MgO values (>10 wt percent) are from 1500 A.D. and 1823 deposits. The range of parental magma compositions based on tephra glasses erupted over a 300 year period is comparable to those observed for the first 15 years of the Pu`u `O`o eruption and about half of the variation observed for summit eruptions from 1832 to 1982. The limited range in tephra parental magma compositions may be related to a lower magma production rate during the period the tephra was erupted.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016BVol...78...39C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016BVol...78...39C"><span>Monitoring crater-wall collapse at active volcanoes: a study of the 12 January 2013 event at Stromboli</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Calvari, Sonia; Intrieri, Emanuele; Di Traglia, Federico; Bonaccorso, Alessandro; Casagli, Nicola; Cristaldi, Antonio</p> <p>2016-05-01</p> <p>Crater-wall collapses are fairly frequent at active volcanoes and they are normally studied through the analysis of their deposits. In this paper, we present an analysis of the 12 January 2013 crater-wall collapse occurring at Stromboli volcano, investigated by means of a monitoring network comprising visible and infrared webcams and a Ground-Based Interferometric Synthetic Aperture Radar. The network revealed the triggering mechanisms of the collapse, which are comparable to the events that heralded the previous effusive eruptions in 1985, 2002, 2007 and 2014. The collapse occurred during a period of inflation of the summit cone and was preceded by increasing explosive activity and the enlargement of the crater. Weakness of the crater wall, increasing magmastatic pressure within the upper conduit induced by ascending magma and mechanical erosion caused by vent opening at the base of the crater wall and by lava fingering, are considered responsible for triggering the collapse on 12 January 2013 at Stromboli. We suggest that the combination of these factors might be a general mechanism to generate crater-wall collapse at active volcanoes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss018e028898.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss018e028898.html"><span>Earth Observations taken by the Expedition 18 Crew</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2009-02-07</p> <p>ISS018-E-028898 (7 Feb. 2009) --- The summit of Popocatepetl Volcano in Mexico is featured in this image photographed by an Expedition 18 crewmember on the International Space Station. Volcano Popocatepetl, a large stratovolcano located approximately 70 kilometers to the southeast of Mexico City, is considered by many volcanologists to be ?the planet?s riskiest volcano?. The volcano warrants this distinction because of its proximity to one of the most densely populated megacities on Earth (population near 23 million in 2009). The variety of potential volcanic hazards at Popocatepetl is also considerable, including explosive eruptions of ash, pyroclastic flows (hot, fluidized masses of rock and gas that flow rapidly downhill), and debris avalanches. This detailed photograph of the summit crater of Popocatepetl (center) also highlights Ventorillo and Noroccidental Glaciers ? together with ice on nearby Iztaccihuatl Volcano and Pico de Orizaba (Mexico?s highest peak and the highest volcano in North America), these are the only mountain glaciers in tropical North America. The presence of glaciers on Popocatepetl is also connected with another volcanic hazard ? the creation of dangerous mudflows, or lahars, should the ice melt during eruptive activity. At the time this image was taken, steam and ash plumes were observed at the volcano ? a faint white steam plume is visible against gray ash deposits on the eastern and southern flanks of the volcano.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006BVol...69..149B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006BVol...69..149B"><span>The exceptional activity and growth of the Southeast Crater, Mount Etna (Italy), between 1996 and 2001</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Behncke, Boris; Neri, Marco; Pecora, Emilio; Zanon, Vittorio</p> <p>2006-09-01</p> <p>Between 1971 and 2001, the Southeast Crater was the most productive of the four summit craters of Mount Etna, with activity that can be compared, on a global scale, to the opening phases of the Pu‘u ‘Ō‘ō-Kūpaianaha eruption of Kīlauea volcano, Hawai‘i. The period of highest eruptive rate was between 1996 and 2001, when near-continuous activity occurred in five phases. These were characterized by a wide range of eruptive styles and intensities from quiet, non-explosive lava emission to brief, violent lava-fountaining episodes. Much of the cone growth occurred during these fountaining episodes, totaling 105 events. Many showed complex dynamics such as different eruptive styles at multiple vents, and resulted in the growth of minor edifices on the flanks of the Southeast Crater cone. Small pyroclastic flows were produced during some of the eruptive episodes, when oblique tephra jets showered the steep flanks of the cone with hot bombs and scoriae. Fluctuations in the eruptive style and eruption rates were controlled by a complex interplay between changes in the conduit geometry (including the growth of a shallow magma reservoir under the Southeast Crater), magma supply rates, and flank instability. During this period, volume calculations were made with the aid of GIS and image analysis of video footage obtained by a monitoring telecamera. Between 1996 and 2001, the bulk volume of the cone increased by ~36×106 m3, giving a total (1971 2001) volume of ~72×106 m3. At the same time, the cone gained ~105 m in height, reaching an elevation of about 3,300 m. The total DRE volume of the 1996 2001 products was ~90×106m3. This mostly comprised lava flows (72×106 m3) erupted at the summit and onto the flanks of the cone. These values indicate that the productivity of the Southeast Crater increased fourfold during 1996 2001 with respect to the previous 25 years, coinciding with a general increase in the eruptive output rates and eruption intensity at Etna. This phase of intense summit activity has been followed, since the summer of 2001, by a period of increased structural instability of the volcano, marked by a series of important flank eruptions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3415678','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3415678"><span>Communication strategies to help reduce the prevalence of non-communicable diseases: Proceedings from the inaugural IFIC Foundation Global Diet and Physical Activity Communications Summit</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Fernstrom, Madelyn H; Reed, Kimberly A; Rahavi, Elizabeth B; Dooher, Carrie C</p> <p>2012-01-01</p> <p>Non-communicable diseases (NCDs), which include cardiovascular disease, cancer, and diabetes, all of which are associated with the common risk factors of poor diet and insufficient physical activity, caused 63% of all deaths globally in 2008. The increasing discussion of global NCDs, including at the 2011 United Nations General Assembly High-level Meeting on the Prevention and Control of Non-communicable Diseases, and a request for multi-stakeholder engagement, prompted the International Food Information Council Foundation to sponsor the Global Diet and Physical Activity Communications Summit: “Insights to Motivate Healthful, Active Lifestyles” on September 19, 2011, in New York City. The Summit brought together a diverse group of stakeholders, representing 34 nations from governments; communication, health, nutrition, and fitness professions; civil society; nonprofits; academia; and the private sector. The Summit provided expert insights and best practices for the use of science-based, behavior-focused communications to motivate individuals to achieve healthful, active lifestyles, with the goal of reducing the prevalence of NCDs. Presented here are some of the highlights and key findings from the Summit. PMID:22537216</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70035238','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70035238"><span>Eruptive history of South Sister, Oregon Cascades</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Fierstein, J.; Hildreth, W.; Calvert, A.T.</p> <p>2011-01-01</p> <p>South Sister is southernmost and highest of the Three Sisters, three geologically dissimilar stratovolcanoes that together form a spectacular 20km reach along the Cascade crest in Oregon. North Sister is a monotonously mafic edifice as old as middle Pleistocene, Middle Sister a basalt-andesite-dacite cone built between 48 and 14ka, and South Sister is a basalt-free edifice that alternated rhyolitic and intermediate modes from 50ka to 2ka (largely contemporaneous with Middle Sister). Detailed mapping, 330 chemical analyses, and 42 radioisotopic ages show that the oldest exposed South Sister lavas were initially rhyolitic ~50ka. By ~37ka, rhyolitic lava flows and domes (72-74% SiO2) began alternating with radially emplaced dacite (63-68% SiO2) and andesite (59-63% SiO2) lava flows. Construction of a broad cone of silicic andesite-dacite (61-64% SiO2) culminated ~30ka in a dominantly explosive sequence that began with crater-forming andesitic eruptions that left fragmental deposits at least 200m thick. This was followed at ~27ka by growth of a steeply dipping summit cone of agglutinate-dominated andesite (56-60.5% SiO2) and formation of a summit crater ~800m wide. This crater was soon filled and overtopped by a thick dacite lava flow and then by >150m of dacitic pyroclastic ejecta. Small-volume dacite lavas (63-67% SiO2) locally cap the pyroclastic pile. A final sheet of mafic agglutinate (54-56% SiO2) - the most mafic product of South Sister - erupted from and drapes the small (300-m-wide) present-day summit crater, ending a summit-building sequence that lasted until ~22ka. A 20kyr-long-hiatus was broken by rhyolite eruptions that produced (1) the Rock Mesa coulee, tephra, and satellite domelets (73.5% SiO2) and (2) the Devils Chain of ~20 domes and short coulees (72.3-72.8% SiO2) from N-S vent alignments on South Sister's flanks. The compositional reversal from mafic summit agglutinate to recent rhyolites epitomizes the frequently changing compositional modes of the South Sister locus throughout its lifetime. South Sister is part of a reach of the Cascades unusually active in the last 50kyr, characterized by high vent density, N-S vent alignments, and numerous eruptive units of true rhyolite (≥ 72% SiO2) that distinguishes it from much of the Quaternary Cascade arc; these are eruptive expressions of the complex confluence of arc and intraplate magmatic-tectonic regimes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JVGR..207..145F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JVGR..207..145F"><span>Eruptive history of South Sister, Oregon Cascades</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fierstein, Judy; Hildreth, Wes; Calvert, Andrew T.</p> <p>2011-10-01</p> <p>South Sister is southernmost and highest of the Three Sisters, three geologically dissimilar stratovolcanoes that together form a spectacular 20 km reach along the Cascade crest in Oregon. North Sister is a monotonously mafic edifice as old as middle Pleistocene, Middle Sister a basalt-andesite-dacite cone built between 48 and 14 ka, and South Sister is a basalt-free edifice that alternated rhyolitic and intermediate modes from 50 ka to 2 ka (largely contemporaneous with Middle Sister). Detailed mapping, 330 chemical analyses, and 42 radioisotopic ages show that the oldest exposed South Sister lavas were initially rhyolitic ~ 50 ka. By ~ 37 ka, rhyolitic lava flows and domes (72-74% SiO 2) began alternating with radially emplaced dacite (63-68% SiO 2) and andesite (59-63% SiO 2) lava flows. Construction of a broad cone of silicic andesite-dacite (61-64% SiO 2) culminated ~ 30 ka in a dominantly explosive sequence that began with crater-forming andesitic eruptions that left fragmental deposits at least 200 m thick. This was followed at ~ 27 ka by growth of a steeply dipping summit cone of agglutinate-dominated andesite (56-60.5% SiO 2) and formation of a summit crater ~ 800 m wide. This crater was soon filled and overtopped by a thick dacite lava flow and then by > 150 m of dacitic pyroclastic ejecta. Small-volume dacite lavas (63-67% SiO 2) locally cap the pyroclastic pile. A final sheet of mafic agglutinate (54-56% SiO 2) - the most mafic product of South Sister - erupted from and drapes the small (300-m-wide) present-day summit crater, ending a summit-building sequence that lasted until ~ 22 ka. A 20 kyr-long-hiatus was broken by rhyolite eruptions that produced (1) the Rock Mesa coulee, tephra, and satellite domelets (73.5% SiO 2) and (2) the Devils Chain of ~ 20 domes and short coulees (72.3-72.8% SiO 2) from N-S vent alignments on South Sister's flanks. The compositional reversal from mafic summit agglutinate to recent rhyolites epitomizes the frequently changing compositional modes of the South Sister locus throughout its lifetime. South Sister is part of a reach of the Cascades unusually active in the last 50 kyr, characterized by high vent density, N-S vent alignments, and numerous eruptive units of true rhyolite (≥ 72% SiO 2) that distinguishes it from much of the Quaternary Cascade arc; these are eruptive expressions of the complex confluence of arc and intraplate magmatic-tectonic regimes.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.V31B3025S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.V31B3025S"><span>Is Kīlauea's East Rift Zone eruption running out of gas?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sutton, A. J.; Elias, T.; Orr, T. R.; Patrick, M. R.; Poland, M. P.; Thornber, C. R.</p> <p>2015-12-01</p> <p>Gases exsolving from magma are a key force that drives eruptive activity, and emissions from Kīlauea's East Rift Zone (ERZ) dominated the volcano's gas release from the beginning of the long-running and voluminous Pu'u 'Ō'ō eruption in 1983, through February 2008. In the months prior to the March 2008 onset of eruptive activity within Halema'uma'u Crater, however, SO2 degassing at the summit climbed substantially, and summit gas release has remained elevated since. These unprecedented emissions associated with the new summit eruption effectively began robbing gas from magma destined for Kīlauea's ERZ. As a result, ERZ SO2discharge, which had averaged 1,700 +-380 t/d for the previous 15 years, declined sharply and steadily beginning in September, 2008, and reached a new steady low of 380 +- 100 t/d by early 2011. This level persisted through mid-2015. In the years since the late 2008 downturn in ERZ SO2 emissions, there has been an overall slowdown in ERZ eruptive activity. Elevated emissions and effusive activity occurred briefly during the 2011 Kamoamoa fissure eruption and two other outbreaks at Pu'u 'Ō'ō , but otherwise ERZ eruptive activity had waned by 2010, when effusion rates were measured at about half of the long-term rate. Also, the sulfur preserved in ERZ olivine melt-inclusions, which provides a record of pre-eruptive SO2degassing, has steadily declined along with equilibration temperatures of host olivine phenocrysts, since 2008. We suggest that the drop in gas content of magma reaching the ERZ, owing to summit pre-eruptive degassing, has contributed significantly to the downturn in ERZ activity. While SO2 emissions from the ERZ have dropped to sustained levels lower than anything seen in the past 20 years, summit emissions have remained some of the highest recorded since regular measurements began at Kīlauea in 1979. Overall, average total SO2 discharge from Kīlauea in 2014, summit and ERZ, is still about 50% higher than for the 15 years prior to 2008. The effects of summit pre-eruptive degassing observed at Kilauea may have application at other summit-rift shield volcanoes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70047248','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70047248"><span>Seismic observations of Redoubt Volcano, Alaska - 1989-2010 and a conceptual model of the Redoubt magmatic system</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Power, John A.; Stihler, Scott D.; Chouet, Bernard A.; Haney, Matthew M.; Ketner, D.M.</p> <p>2013-01-01</p> <p>Seismic activity at Redoubt Volcano, Alaska, has been closely monitored since 1989 by a network of five to ten seismometers within 22 km of the volcano's summit. Major eruptions occurred in 1989-1990 and 2009 and were characterized by large volcanic explosions, episodes of lava dome growth and failure, pyroclastic flows, and lahars. Seismic features of the 1989-1990 eruption were 1) weak precursory tremor and a short, 23-hour-long, intense swarm of repetitive shallow long-period (LP) events centered 1.4 km below the crater floor, 2) shallow volcano-tectonic (VT) and hybrid earthquakes that separated early episodes of dome growth, 3) 13 additional swarms of LP events at shallow depths precursory to many of the 25 explosions that occurred over the more than 128 day duration of eruptive activity, and 4) a persistent cluster of VT earthquakes at 6 to 9 km depth. In contrast the 2009 eruption was preceded by a pronounced increase in deep-LP (DLP) events at lower crustal depths (25 to 38 km) that began in mid-December 2008, two months of discontinuous shallow volcanic tremor that started on January 23, 2009, a strong phreatic explosion on March 15, and a 58-hour-long swarm of repetitive shallow LP events. The 2009 eruption consisted of at least 23 major explosions between March 23 and April 5, again accompanied by shallow VT earthquakes, several episodes of shallow repetitive LP events and dome growth continuing until mid July. Increased VT earthquakes at 4 to 9 km depth began slowly in early April, possibly defining a mid-crustal magma source zone. Magmatic processes associated with the 2009 eruption seismically activated the same portions of the Redoubt magmatic system as the 1989-1990 eruption, although the time scales and intensity vary considerably among the two eruptions. The occurrence of precursory DLP events suggests that the 2009 eruption may have involved the rise of magma from lower crustal depths. Based on the evolution of seismicity during the 1989-1990 and 2009 eruptions the Redoubt magmatic system is envisioned to consist of a shallow system of cracks extending 1 to 2 km below the crater floor, a magma storage or source region at roughly 3 to 9 km depth, and a diffuse magma source region at 25 to 38 km depth. Close tracking of seismic activity allowed the Alaska Volcano Observatory to successfully issue warnings prior to many of the hazardous explosive events that occurred in 2009.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA22152.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA22152.html"><span>Investigating Mars: Arsia Mons</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2017-12-27</p> <p>This VIS image shows part of the eastern margin of the summit caldera of Arsia Mons. The arcuate features are the faults created by collapse of summit materials. A massive eruption can empty the large magma chamber which existed within the volcano, creating a void which can not support the weight of the top of the volcano. Arsia Mons is the southernmost of the Tharsis volcanoes. It is 270 miles (450km) in diameter, almost 12 miles (20km) high, and the summit caldera is 72 miles (120km) wide. For comparison, the largest volcano on Earth is Mauna Loa. From its base on the sea floor, Mauna Loa measures only 6.3 miles high and 75 miles in diameter. A large volcanic crater known as a caldera is located at the summit of all of the Tharsis volcanoes. These calderas are produced by massive volcanic explosions and collapse. The Arsia Mons summit caldera is larger than many volcanoes on Earth. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 12487 Latitude: -9.44031 Longitude: 240.527 Instrument: VIS Captured: 2004-10-07 11:58 https://photojournal.jpl.nasa.gov/catalog/PIA22152</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21085177','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21085177"><span>Intrusion triggering of the 2010 Eyjafjallajökull explosive eruption.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sigmundsson, Freysteinn; Hreinsdóttir, Sigrún; Hooper, Andrew; Arnadóttir, Thóra; Pedersen, Rikke; Roberts, Matthew J; Oskarsson, Níels; Auriac, Amandine; Decriem, Judicael; Einarsson, Páll; Geirsson, Halldór; Hensch, Martin; Ofeigsson, Benedikt G; Sturkell, Erik; Sveinbjörnsson, Hjörleifur; Feigl, Kurt L</p> <p>2010-11-18</p> <p>Gradual inflation of magma chambers often precedes eruptions at highly active volcanoes. During such eruptions, rapid deflation occurs as magma flows out and pressure is reduced. Less is known about the deformation style at moderately active volcanoes, such as Eyjafjallajökull, Iceland, where an explosive summit eruption of trachyandesite beginning on 14 April 2010 caused exceptional disruption to air traffic, closing airspace over much of Europe for days. This eruption was preceded by an effusive flank eruption of basalt from 20 March to 12 April 2010. The 2010 eruptions are the culmination of 18 years of intermittent volcanic unrest. Here we show that deformation associated with the eruptions was unusual because it did not relate to pressure changes within a single magma chamber. Deformation was rapid before the first eruption (>5 mm per day after 4 March), but negligible during it. Lack of distinct co-eruptive deflation indicates that the net volume of magma drained from shallow depth during this eruption was small; rather, magma flowed from considerable depth. Before the eruption, a ∼0.05 km(3) magmatic intrusion grew over a period of three months, in a temporally and spatially complex manner, as revealed by GPS (Global Positioning System) geodetic measurements and interferometric analysis of satellite radar images. The second eruption occurred within the ice-capped caldera of the volcano, with explosivity amplified by magma-ice interaction. Gradual contraction of a source, distinct from the pre-eruptive inflation sources, is evident from geodetic data. Eyjafjallajökull's behaviour can be attributed to its off-rift setting with a 'cold' subsurface structure and limited magma at shallow depth, as may be typical for moderately active volcanoes. Clear signs of volcanic unrest signals over years to weeks may indicate reawakening of such volcanoes, whereas immediate short-term eruption precursors may be subtle and difficult to detect.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.8783G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.8783G"><span>Textural constraints on the dynamics of the 2000 Miyakejima eruption</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Garozzo, Ileana; Romano, Claudia; Giordano, Guido; Geshi, Nobuo; Vona, Alessandro</p> <p>2016-04-01</p> <p>Miyakejima Volcano is a basaltic-andesite stratovolcano active from ~10.000 years, located on the north of the Izu-Bonin arc. During the last 600 years the volcano has been characterized mainly by flank fissure activity, with explosive phreatomagmatic eruptions on the coastal areas. In the last century, the activity became more frequent and regular with intervals of 20 to 70 years (1940, 1962, 1983 and 2000). The last activity started on 27 June 2000, with a minor submarine eruption on the west coast of the volcano, and proceeded with six major summit eruptions from July 8 to August 29. The eruptions led to the formation of a collapse caldera ~1.6 km across. The total erupted tephra represents only 1.7% in volume of the caldera, the high fragmentation of magma produced mainly fine-grained volcanic ash. In order to improve the understanding on the triggering and dynamics of this explosive eruption, we carried out a detailed investigation of the erupted materials with particular attention to the textural features of juvenile pyroclasts (Vesicle and Crystal Size Distributions). The stratigraphic record can be divided into six fall units, corresponding to the six summit eruptions, although juvenile materials were identified only in 4 units (unit 2, 4, 5, 6). We selected about 100 juvenile grains sampled from the bottom to the top of each level, to be analyzed by scanning electron microscopy. The study of juvenile morphological features allowed us to recognize the existence of three characteristic morphotypes, showing marked differences in their external morphologies and internal textures (from poorly to highly crystallized and vesiculated clasts). The distribution of these morphotypes is non-homogeneous along the eruptive sequence indicating changes of dynamics during magma ascent. Juveniles do not show features inherited from the interaction with external water. Vesicle Volume Distributions of the selected ash grains show that the three types of pyroclasts experienced different nucleation and growth processes. Also the Vesicles Number Densities (VNDs) vary of about one order of magnitude in the different populations (from 107 to 108 cm-3), with values comparable with those commonly related to sub-Plinian and Plinian eruptions. Data from the CSD analysis show perfect agreement with the measured VNDs (crystal population densities increasing with VNDs), suggesting a link between the degassing history and the syn-eruptive crystallization. The results of the textural analysis are used to produce a conduit model for the 2000 Miyakejima eruption. Textural analysis and modeling data are presented to reconstruct the eruptive dynamics leading to this high - energetic eruption.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70010084','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70010084"><span>Caldera collapse in the Galápagos Islands, 1968</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Simkin, T.; Howard, K.A.</p> <p>1970-01-01</p> <p>The summit caldera of Isla Fernandina, a large, uninhabited basaltic shield volcano, was further enlarged by 1 to 2 km3 in June 1968. A small quake and large vapor cloud on 11 June were followed 4 hours later by a remarkable volcanic ash cloud and, after another hour, by a major explosion recorded at infrasonic stations throughout the hemisphere. Seismic activity increased to a peak on 19 June, when more than 200 events per day were recorded by a seismograph 140 km away. Several hundred quakes were in the magnitude range 4.0 to 5.4 mb, but few such events were recorded after 23 June. Unusual lightning accompanied the major cloud, and, during the evening of 11 June, distant observers reported red glow and flashes from the area. Fine ash fell that night and much of the next day to distances at least 350 km from the volcano.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMNH43B1758S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMNH43B1758S"><span>Eruptive history, current activity and risk estimation using geospatial information in the Colima volcano, Mexico</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Suarez-Plascencia, C.; Camarena-Garcia, M.; Nunez-Cornu, F. J.; Flores-Peña, S.</p> <p>2013-12-01</p> <p>Colima volcano, also known as Volcan de Fuego (19 30.696 N, 103 37.026 W), is located on the border between the states of Jalisco and Colima, and is the most active volcano in Mexico. In January 20, 1913, Colima had its biggest explosion of the twentieth century, with VEI 4, after the volcano had been dormant for almost 40 years. In 1961, a dome reached the northeastern edge of the crater and started a new lava flow, and from this date maintains constant activity. In February 10, 1999, a new explosion occurred at the summit dome. The activity during the 2001-2005 period was the most intense, but did not exceed VEI 3. The activity resulted in the formation of domes and their destruction after explosive events. The explosions originated eruptive columns, reaching altitudes between 4,500 and 9,000 masl, further pyroclastic flows reaching distances up to 3.5 km from the crater. During the explosive events, ash emissions were generated in all directions reaching distances up to 100 km, slightly affecting the nearby villages: Tuxpan, Tonila, Zapotlan, Cuauhtemoc, Comala, Zapotitlan de Vadillo and Toliman. During 2005 to July 2013, this volcano has had an intense effusive-explosive activity; similar to the one that took place during the period of 1890 through 1905. That was before the Plinian eruption of 1913, where pyroclastic flows reached a distance of 15 km from the crater. In this paper we estimate the risk of Colima volcano through the analysis of the vulnerability variables, hazard and exposure, for which we use: satellite imagery, recurring Fenix helicopter over flights of the state government of Jalisco, the use of the images of Google Earth and the population census 2010 INEGI. With this information and data identified changes in economic activities, development, and use of land. The expansion of the agricultural frontier in the lower sides of the volcano Colima, and with the advancement of traditional crops of sugar cane and corn, increased the growth of avocado orchards and fruits like blueberries, raspberries, and blackberries within the radius of 15 km from the crater. The population dynamics in the Colima volcano area had a population of 552,954 inhabitants in 2010, and a growth at an annual rate of 1.6 percent of the total population. 60 percent of the populations live in 105 towns with a population less than 250 inhabitants. Also, the region showed an increase in vulnerability for the development of economic activities, supported by the highway, railway, natural gas pipelines and electrical infrastructure that connect to the Port of Manzanillo to Guadalajara city. With the use of geospatial information quantify the vulnerability, together with the hazard maps and exposure, enabled us to build the following volcanic risk maps: a) Exclusion areas and moderate hazard for explosive events (ballistic) and pyroclastic flows, b) Hazard map of lahars and debris flow, and c) Hazard map of ash-fall. The geospatial database, a GIS mapping and current volcano monitoring, are the basis of the Operational Plan Colima Volcano. Civil Protection by the state of Jalisco and the updating of urban development plans of municipalities converge on the volcano. These instruments of land planning will help reduce volcanic risk in the region.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1985EOSTr..66Q1209.','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1985EOSTr..66Q1209."><span>Ruiz Volcano: Preliminary report</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p></p> <p></p> <p>Ruiz Volcano, Colombia (4.88°N, 75.32°W). All times are local (= GMT -5 hours).An explosive eruption on November 13, 1985, melted ice and snow in the summit area, generating lahars that flowed tens of kilometers down flank river valleys, killing more than 20,000 people. This is history's fourth largest single-eruption death toll, behind only Tambora in 1815 (92,000), Krakatau in 1883 (36,000), and Mount Pelée in May 1902 (28,000). The following briefly summarizes the very preliminary and inevitably conflicting information that had been received by press time.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.6881B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.6881B"><span>Dynamics and functional model of the 2012-13 flank fissure eruption of Tolbachik volcano in Kamchatka, Russia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Belousov, Alexander; Belousova, Marina; Edwards, Benjamin</p> <p>2017-04-01</p> <p>The 2012-13 flank fissure eruption of Tolbachik in Kamchatka Peninsula lasted more than nine months and discharged 0.55 cub.km DRE of basaltic trachyandesite magma. It is one of the most voluminous historical eruptions of mafic magma at subduction-related volcano globally, and is the second largest in Kamchatka. We present a broad overview of the eruption as well as a model for the magma storage and transport system of Plosky Tolbachik Volcano. The 2012-13 eruption was preceded by five months of elevated seismicity and ground inflation, both of which peaked a day before the eruption commenced on 27 November 2012. The batch of high-Al magma ascended from depths of 5-10 km; its apical part contained 54-55 wt.% SiO2, and the main body 52-53 wt.% SiO2. The eruption started by the opening of a 6 km-long radial fissure on the southwestern slope of the volcano that fed multi-vent phreatomagmatic and magmatic explosive activity, as well as intensive effusion of lava with an initial discharge of 440 cub.m/s. After 10 days the eruption continued only at the lower part of the fissure, where explosive and effusive activity of Hawaiian-Strombolian type occurred from a lava pond in the crater of the main growing scoria cone. The discharge rate for the nine month long, effusion-dominated eruption gradually declined from 140 to 18 cub.m/s and formed a compound lava field with a total area of 36 sq.km; the effusive activity evolved from high-discharge channel-fed 'a'a lavas to dominantly low-discharge tube-fed pahoehoe lavas. On 23 August, the effusion of lava ceased and the intra-crater lava pond drained. Weak Strombolian-type explosions continued for several more days on the crater bottom until the end of the eruption around 5 September 2013. The volcanic system, comprising the stratovolcano Plosky Tolbachik and its two radial volcanic rifts, produces alternating eruptions of two genetically related magma types: high-Al basalt (eruptions at the summit and along both rift zones) and high-Mg basalt (eruptions only along the southwest rift). The high-Al magma ascends to the surface from a magma storage zone at a depth of about 5 km below the summit of Plosky Tolbachik. During the 2012-13 eruption the high-Al magma first ascended along the central conduit of the volcano. Then the feeding dyke deviated from the conduit and propagated sub-horizontally along the southwest rift at a depth about 1 km below sea level. The 1975-76 Southern Breakthrough of the volcano was fed in a similar way. In contrast, the 1975-76 Northern Breakthrough of the volcano was fed by vertical dyke of high-Mg magma that ascended to the ground surface from the magma storage zone located directly below the area of the Breakthrough at a depth of approximately 20 km.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.epa.gov/enforcement/summit-renovations-inc-information-sheet','PESTICIDES'); return false;" href="https://www.epa.gov/enforcement/summit-renovations-inc-information-sheet"><span>Summit Renovations, Inc. Information Sheet</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.epa.gov/pesticides/search.htm">EPA Pesticide Factsheets</a></p> <p></p> <p></p> <p>Summit Renovations, Inc. (the Company) is located in Centennial, Colorado. The settlement involves renovation activities conducted at a property constructed prior to 1978, located in Denver, Colorado.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21518980','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21518980"><span>The power of play: Innovations in Getting Active Summit 2011: a science panel proceedings report from the American Heart Association.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lieberman, Debra A; Chamberlin, Barbara; Medina, Ernie; Franklin, Barry A; Sanner, Brigid McHugh; Vafiadis, Dorothea K</p> <p>2011-05-31</p> <p>To examine the influence active-play video gaming (also referred to as exergaming, exertainment, and active gaming) might have on improving health-related skills, enhancing self-esteem and self-efficacy, promoting social support, and ultimately motivating positive changes in health behaviors, the American Heart Association convened The Power of Play: Innovations in Getting Active Summit. The summit, as well as a follow-up science panel, was hosted by the American Heart Association and Nintendo of America. The science panel discussed the current state of research on active-play video gaming and its potential to serve as a gateway experience that might motivate players to increase the amount and intensity of physical activity in their daily lives. The panel identified the need for continued research on the gateway concept and on other behavioral health outcomes that could result from active-play video games and considered how these games could potentially affect disparate populations. The summit represented an exciting first step in convening healthcare providers, behavioral researchers, and professionals from the active-play video game industry to discuss the potential health benefits of active-play video games. Research is needed to improve understanding of processes of behavior change with active games. Future games and technologies may be designed with the goal to optimize physical activity participation, increase energy expenditure, and effectively address the abilities and interests of diverse and targeted populations. The summit helped the participants gain an understanding of what is known, identified gaps in current research, and supported a dialogue for continued collaboration.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70036848','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70036848"><span>Kulanaokuaiki Tephra (ca, A.D. 400-1000): Newly recognized evidence for highly explosive eruptions at Kilauea Volcano, Hawai'i</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Fiske, R.S.; Rose, T.R.; Swanson, D.A.; Champion, D.E.; McGeehin, J.P.</p> <p>2009-01-01</p> <p>K??lauea may be one of the world's most intensively monitored volcanoes, but its eruptive history over the past several thousand years remains rather poorly known. Our study has revealed the vestiges of thin basaltic tephra deposits, overlooked by previous workers, that originally blanketed wide, near-summit areas and extended more than 17 km to the south coast of Hawai'i. These deposits, correlative with parts of tephra units at the summit and at sites farther north and northwest, show that K??lauea, commonly regarded as a gentle volcano, was the site of energetic pyroclastic eruptions and indicate the volcano is significantly more hazardous than previously realized. Seventeen new calibrated accelerator mass spectrometry (AMS) radiocarbon ages suggest these deposits, here named the Kulanaokuaiki Tephra, were emplaced ca. A.D. 400-1000, a time of no previously known pyroclastic activity at the volcano. Tephra correlations are based chiefly on a marker unit that contains unusually high values of TiO2 and K2O and on paleomagnetic signatures of associated lava flows, which show that the Kulanaokuaiki deposits are the time-stratigraphic equivalent of the upper part of a newly exhumed section of the Uw??kahuna Ash in the volcano's northwest caldera wall. This section, thought to have been permanently buried by rockfalls in 1983, is thicker and more complete than the previously accepted type Uw??kahuna at the base of the caldera wall. Collectively, these findings justify the elevation of the Uw??kahuna Ash to formation status; the newly recognized Kulanaokuaiki Tephra to the south, the chief focus of this study, is defined as a member of the Uw??kahuna Ash. The Kulanaokuaiki Tephra is the product of energetic pyroclastic falls; no surge- or pyroclastic-flow deposits were identified with certainty, despite recent interpretations that Uw??kahuna surges extended 10-20 km from K??lauea's summit. ?? 2009 Geological Society of America.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018E%26PSL.482..193N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018E%26PSL.482..193N"><span>Understanding cyclic seismicity and ground deformation patterns at volcanoes: Intriguing lessons from Tungurahua volcano, Ecuador</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Neuberg, Jürgen W.; Collinson, Amy S. D.; Mothes, Patricia A.; Ruiz, Mario C.; Aguaiza, Santiago</p> <p>2018-01-01</p> <p>Cyclic seismicity and ground deformation patterns are observed on many volcanoes worldwide where seismic swarms and the tilt of the volcanic flanks provide sensitive tools to assess the state of volcanic activity. Ground deformation at active volcanoes is often interpreted as pressure changes in a magmatic reservoir, and tilt is simply translated accordingly into inflation and deflation of such a reservoir. Tilt data recorded by an instrument in the summit area of Tungurahua volcano in Ecuador, however, show an intriguing and unexpected behaviour on several occasions: prior to a Vulcanian explosion when a pressurisation of the system would be expected, the tilt signal declines significantly, hence indicating depressurisation. At the same time, seismicity increases drastically. Envisaging that such a pattern could carry the potential to forecast Vulcanian explosions on Tungurahua, we use numerical modelling and reproduce the observed tilt patterns in both space and time. We demonstrate that the tilt signal can be more easily explained as caused by shear stress due to viscous flow resistance, rather than by pressurisation of the magmatic plumbing system. In general, our numerical models prove that if magma shear viscosity and ascent rate are high enough, the resulting shear stress is sufficient to generate a tilt signal as observed on Tungurahua. Furthermore, we address the interdependence of tilt and seismicity through shear stress partitioning and suggest that a joint interpretation of tilt and seismicity can shed new light on the eruption potential of silicic volcanoes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19860059227&hterms=active+volcanoes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dactive%2Bvolcanoes','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19860059227&hterms=active+volcanoes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dactive%2Bvolcanoes"><span>Application of photogrammetry to the study of volcano-glacier interactions on Mount Wrangell, Alaska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Benson, C. S.; Follett, A. B.</p> <p>1986-01-01</p> <p>Most Alaskan volcanoes are glacier covered and provide excellent opportunities to study interactions between glaciers and volcanoes. The present paper is concerned with such a study, taking into account the Mt. Wrangell (4317 m) which is the northernmost active volcano (solfatara activity) on the Pacific Rim (62 deg N; 144 deg W). While the first photographs on the summit of Mt. Wrangell were published more than 75 years ago, research there began in 1953 and 1954. Satellite images reveal activity at the summit of Mt. Wrangell. However, the resolution is not sufficient for conducting important measurements regarding ice volume losses. For this reason, vertical aerial photographs of the summit were obtained, and a field trip to the summit was conducted. Aspects of photogrammetry are discussed, taking into account questions of ground control, aerial photography, topographic mapping, digital cross sections, and orthophotos.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.V33F..07F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.V33F..07F"><span>Comparing eruptions of varying intensity at Kilauea via melt inclusion analysis</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ferguson, D. J.; Plank, T. A.; Hauri, E. H.; Houghton, B. F.; Gonnermann, H. M.; Swanson, D. A.; Blaser, A. P.</p> <p>2013-12-01</p> <p>Over the past 500 years explosive summit eruptions from Kilauea volcano, Hawaii, have exhibited a range of eruption magnitudes, from large basaltic sub-plinian events to Hawaiian lava fountains of various intensity. Knowledge of the factors controlling such dramatic changes in explosivity and mass discharge rate is vital for understanding the dynamics of explosive basaltic magma systems, but these remain poorly constrained. At Kilauea this information also has important implications for hazard assessment, as future eruptions may be far larger than those observed historically. To investigate the processes associated with eruptions of varying magnitudes we have analyzed the composition and dissolved volatile contents (H2O-CO2-S-Cl-F) of olivine-hosted melt inclusions, sampled from tephra deposits associated with three eruptions of different sizes: a moderate lava-fountain (1959 Episode of Kilauea Iki); an exceptionally high lava-fountain (1500 CE Keanakāko'i reticulite) and a basaltic sub-plinian eruption (1650 CE Keanakāko'i layer 6 scoria). Over this time period (~500 years) we find no major shifts in the major element composition of primary melts feeding the Kilauea magmatic system, and melt inclusions from all eruptions record similar maximum water (~0.7 wt% H2O) and CO2 (~300 ppm) contents, regardless of eruption magnitude. Co-variations between other volatile species, such as CO2 and S, do not support a role for excess volatiles (i.e. CO2) in the larger eruptions via ';gas-fluxing'. Our data therefore suggests that major shifts in eruptive magnitude are unlikely to be linked to either changes in the primary volatile content of the melts or excess gas supplied by open-system degassing of deeper melts. Rather we find evidence for significant variations in the shallow degassing behavior of magmas associated with the larger Keanakāko'i eruptions (sub-plinian and strong lava-fountaining events) compared to that from less vigorous moderate Kilauea Iki lava-fountaining events. On plots of CO2 versus H2O, Kilauea Iki MI's record volatile contents consistent with equilibrium degassing of magma rising from a depth of ~3 km. In contrast, the volatile contents of melts from the more explosive eruptions appear to be strongly affected by degassing processes at shallow depths (< 300 m), indicating variations in the ascent and storage of melts over this time-period. These changes in storage conditions may be linked to variations in the depth of the summit caldera, which was significantly greater during the older more explosive eruptive phases.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/1429211-exposing-hierarchical-parallelism-flash-code-supernova-simulation-summit-other-architectures','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1429211-exposing-hierarchical-parallelism-flash-code-supernova-simulation-summit-other-architectures"><span>Exposing Hierarchical Parallelism in the FLASH Code for Supernova Simulation on Summit and Other Architectures</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Papatheodore, Thomas L.; Messer, Bronson</p> <p></p> <p>Since roughly 100 million years after the big bang, the primordial elements hydrogen (H), helium (He), and lithium (Li) have been synthesized into heavier elements by thermonuclear reactions inside of the stars. The change in stellar composition resulting from these reactions causes stars to evolve over the course of their lives. Although most stars burn through their nuclear fuel and end their lives quietly as inert, compact objects, whereas others end in explosive deaths. These stellar explosions are called supernovae and are among the most energetic events known to occur in our universe. Supernovae themselves further process the matter ofmore » their progenitor stars and distribute this material into the interstellar medium of their host galaxies. In the process, they generate ∼1051 ergs of kinetic energy by sending shock waves into their surroundings, thereby contributing to galactic dynamics as well.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.V21C0727C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.V21C0727C"><span>Magma Vesiculation and Infrasonic Activity in Open Conduit Volcanoes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Colo', L.; Baker, D. R.; Polacci, M.; Ripepe, M.</p> <p>2007-12-01</p> <p>At persistently active basaltic volcanoes such as Stromboli, Italy degassing of the magma column can occur in "passive" and "active" conditions. Passive degassing is generally understood as a continuous, non explosive release of gas mainly from the open summit vents and subordinately from the conduit's wall or from fumaroles. In passive degassing generally gas is in equilibrium with atmospheric pressure, while in active degassing the gas approaches the surface at overpressurized conditions. During active degassing (or puffing), the magma column is interested by the bursting of small gas bubbles at the magma free surface and, as a consequence, the active degassing process generates infrasonic signals. We postulated, in this study, that the rate and the amplitude of infrasonic activity is somehow linked to the rate and the volume of the overpressured gas bubbles, which are generated in the magma column. Our hypothesis is that infrasound is controlled by the quantities of gas exsolved in the magma column and then, that a relationship between infrasound and the vesiculation process should exist. In order to achieve this goal, infrasonic records and bubble size distributions of scoria samples from normal explosive activity at Stromboli processed via X ray tomography have been compared. We observed that the cumulative distribution for both data sets follow similar power laws, indicating that both processes are controlled by a scale invariant phenomenon. However the power law is not stable but changes in different scoria clasts, reflecting when gas bubble nucleation is predominant over bubbles coalescence and viceversa. The power law also changes for the infrasonic activity from time to time, suggesting that infrasound may be controlled also by a different gas exsolution within the magma column. Changes in power law distributions are the same for infrasound and scoria indicating that they are linked to the same process acting in the magmatic system. We suggest that monitoring infrasound on an active volcano could represent an alternative way to monitor the vesiculation process of an open conduit system.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.V31A3074S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.V31A3074S"><span>Measuring Gases Using Drones at Turrialba Volcano, Costa Rica</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stix, J.; Alan, A., Jr.; Corrales, E.; D'Arcy, F.; de Moor, M. J.; Diaz, J. A.</p> <p>2016-12-01</p> <p>We are currently developing a series of drones and associated instrumentation to study Turrialba volcano in Costa Rica. This volcano has shown increasing activity during the last 20 years, and the volcano is currently in a state of heightened unrest as exemplified by recent explosive activity in May-August 2016. The eruptive activity has made the summit area inaccessible to normal gas monitoring activities, prompting development of new techniques to measure gas compositions. We have been using two drones, a DJI Spreading Wings S1000 octocopter and a Turbo Ace Matrix-i quadcopter, to airlift a series of instruments to measure volcanic gases in the plume of the volcano. These instruments comprise optical and electrochemical sensors to measure CO2, SO2, and H2S concentrations which are considered the most significant species to help forecast explosive eruptions and determine the relative proportions of magmatic and hydrothermal components in the volcanic gas. Additionally, cameras and sensors to measure air temperature, relative humidity, atmospheric pressure, and GPS location are included in the package to provide meteorological and geo-referenced information to complement the concentration data and provide a better picture of the volcano from a remote location. The integrated payloads weigh 1-2 kg, which can typically be flown by the drones in 10-20 minutes at altitudes of 2000-4000 meters. Preliminary tests at Turrialba in May 2016 have been very encouraging, and we are in the process of refining both the drones and the instrumentation packages for future flights. Our broader goals are to map gases in detail with the drones in order to make flux measurements of each species, and to apply this approach at other volcanoes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70102155','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70102155"><span>Summit crater lake observations, and the location, chemistry, and pH of water samples near Mount Chiginagak volcano, Alaska: 2004-2012</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Schaefer, Janet R.; Scott, William E.; Evans, William C.; Wang, Bronwen; McGimsey, Robert G.</p> <p>2013-01-01</p> <p>Mount Chiginagak is a hydrothermally active volcano on the Alaska Peninsula, approximately 170 km south–southwest of King Salmon, Alaska (fig. 1). This small stratovolcano, approximately 8 km in diameter, has erupted through Tertiary to Permian sedimentary and igneous rocks (Detterman and others, 1987). The highest peak is at an elevation of 2,135 m, and the upper ~1,000 m of the volcano are covered with snow and ice. Holocene activity consists of debris avalanches, lahars, and lava flows. Pleistocene pyroclastic flows and block-and-ash flows, interlayered with andesitic lava flows, dominate the edifice rocks on the northern and western flanks. Historical reports of activity are limited and generally describe “steaming” and “smoking” (Coats, 1950; Powers, 1958). Proximal tephra collected during recent fieldwork suggests there may have been limited Holocene explosive activity that resulted in localized ash fall. A cluster of fumaroles on the north flank, at an elevation of ~1,750 m, commonly referred to as the “north flank fumarole” have been emitting gas throughout historical time (location shown in fig. 2). The only other thermal feature at the volcano is the Mother Goose hot springs located at the base of the edifice on the northwestern flank in upper Volcano Creek, at an elevation of ~160 m (fig. 2, near sites H1, H3, and H4). Sometime between November 2004 and May 2005, a ~400-m-wide, 100-m-deep lake developed in the snow- and ice-filled summit crater of the volcano (Schaefer and others, 2008). In early May 2005, an estimated 3 million cubic meters (3×106 m3) of sulfurous, clay-rich debris and acidic water exited the crater through tunnels at the base of a glacier that breaches the south crater rim. More than 27 km downstream, these acidic flood waters reached approximately 1.3 m above normal water levels and inundated a fertile, salmon-spawning drainage, acidifying the entire water column of Mother Goose Lake from its surface waters to its maximum depth of 45 m (resulting pH ~2.9), and preventing the annual salmon run in the King Salmon River. A simultaneous release of gas and acidic aerosols from the crater caused widespread vegetation damage along the flow path. Since 2005, we have been monitoring the crater lake water that continues to flow into Mother Goose Lake by collecting surface water samples for major cation and anion analysis, measuring surface-water pH of affected drainages, and photo-documenting the condition of the summit crater lake. This report describes water sampling locations, provides a table of chemistry and pH measurements, and documents the condition of the summit crater between 2004 and 2011. In September 2013, the report was updated with results of water-chemistry samples collected in 2011 and 2012, which were added as an addendum.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.V33F..01O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.V33F..01O"><span>Low intensity hawaiian fountaining as exemplified by the March 2011, Kamoamoa eruption at Kilauea Volcano, Hawai`i (Invited)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Orr, T. R.; Houghton, B. F.; Poland, M. P.; Patrick, M. R.; Thelen, W. A.; Sutton, A. J.; Parcheta, C. E.; Thornber, C. R.</p> <p>2013-12-01</p> <p>The latest 'classic' hawaiian high-fountaining activity at Kilauea Volcano occurred in 1983-1986 with construction of the Pu`u `O`o pyroclastic cone. Since then, eruptions at Kilauea have been dominated by nearly continuous effusive activity. Episodes of sustained low hawaiian fountaining have occurred but are rare and restricted to short-lived fissure eruptions along Kilauea's east rift zone. The most recent of these weakly explosive fissure eruptions--the Kamoamoa eruption--occurred 5-9 March 2011. The Kamoamoa eruption was probably the consequence of a decrease in the carrying capacity of the conduit feeding the episode 58 eruptive vent down-rift from Pu`u `O`o in Kilauea's east rift zone. As output from the vent waned, Kilauea's summit magma storage and east rift zone transport system began to pressurize, as manifested by an increase in seismicity along the upper east rift zone, inflation of the summit and Pu`u `O`o, expansion of the east rift zone, and rising lava levels at both the summit and Pu`u `O`o. A dike began propagating towards the surface from beneath Makaopuhi Crater, 6 km west of Pu`u `O`o, at 1342 Hawaiian Standard Time (UTC - 10 hours) on 5 March. A fissure eruption started about 3.5 hours later near Nāpau Crater, 2 km uprift of Pu`u `O`o. Activity initially jumped between numerous en echelon fissure segments before centering on discrete vents near both ends of the 2.4-km-long fissure system for the final two days of the eruption. About 2.6 mcm of lava was erupted over the course of four days with a peak eruption rate of 11 m3/s. The petrologic characteristics of the fissure-fed lava indicate mixing between hotter mantle-derived magma and cooler rift-stored magma, with a greater proportion of the cooler component than was present in east rift zone lava erupting before March 2011. The fissure eruption was accompanied by the highest SO2 emission rates since 1986. Coincidentally, the summit and Pu`u `O`o deflated as magma drained away, causing expansion of the ERZ. The geological, geophysical, and geochemical datasets collected before, during, and after the Kamoamoa eruption provide an unprecedented account of what, at least in recent decades, is the 'normal' mode for hawaiian fountaining at Kilauea--that is, low intensity fissure-fed eruptions. This activity differs from high fountaining in that there is little physical coupling between melt and magmatic gas--for much of the Kamoamoa eruption lava ponded sluggishly over the vents and was weakly disrupted by bursts from trains of very closely spaced gas bubbles. Such eruptions enable us to examine the middle ground between strombolian and classical hawaiian behaviors at basaltic volcanoes.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014Geomo.207...51P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014Geomo.207...51P"><span>Lahar hazard assessment in the southern drainage system of Cotopaxi volcano, Ecuador: Results from multiscale lahar simulations</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pistolesi, Marco; Cioni, Raffaello; Rosi, Mauro; Aguilera, Eduardo</p> <p>2014-02-01</p> <p>The ice-capped Cotopaxi volcano is known worldwide for the large-scale, catastrophic lahars that have occurred in connection with historical explosive eruptions. The most recent large-scale lahar event occurred in 1877 when scoria flows partially melted ice and snow of the summit glacier, generating debris flows that severely impacted all the river valleys originating from the volcano. The 1877 lahars have been considered in the recent years as a maximum expected event to define the hazard associated to lahar generation at Cotopaxi. Conversely, recent field-based studies have shown that such debris flows have occurred several times during the last 800 years of activity at Cotopaxi, and that the scale of lahars has been variable, including events much larger than that of 1877. Despite a rapid retreat of the summit ice cap over the past century, in fact, there are no data clearly suggesting that future events will be smaller than those observed in the deposits of the last 800 years of activity. In addition, geological field data prove that the lahar triggering mechanism also has to be considered as a key input parameter and, under appropriate eruptive mechanisms, a hazard scenario of a lahar with a volume 3-times larger than the 1877 event is likely. In order to analyze the impact scenarios in the southern drainage system of the volcano, simulations of inundation areas were performed with a semi-empirical model (LAHARZ), using input parameters including variable water volume. Results indicate that a lahar 3-times larger than the 1877 event would invade much wider areas than those flooded by the 1877 lahars along the southern valley system, eventually impacting highly-urbanized areas such as the city of Latacunga.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.V41C..02D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.V41C..02D"><span>Preliminary results from an integrated, multi-parameter, experiment at the Santiaguito lava dome complex, Guatemala</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>De Angelis, S.; Rietbrock, A.; Lavallée, Y.; Lamb, O. D.; Lamur, A.; Kendrick, J. E.; Hornby, A. J.; von Aulock, F. W.; Chigna, G.</p> <p>2016-12-01</p> <p>Understanding the complex processes that drive volcanic unrest is crucial to effective risk mitigation. Characterization of these processes, and the mechanisms of volcanic eruptions, is only possible when high-resolution geophysical and geological observations are available over comparatively long periods of time. In November 2014, the Liverpool Earth Observatory, UK, in collaboration with the Instituto Nacional de Sismologia, Meteorologia e Hidrologia (INSIVUMEH), Guatemala, established a multi-parameter geophysical network at Santiaguito, one of the most active volcanoes in Guatemala. Activity at Santiaguito throughout the past decade, until the summer of 2015, was characterized by nearly continuous lava dome extrusion accompanied by frequent and regular small-to-moderate gas or gas-and-ash explosions. Over the past two years our network collected a wealth of seismic, acoustic and deformation data, complemented by campaign visual and thermal infrared measurements, and rock and ash samples. Here we present preliminary results from the analysis of this unique dataset. Using acoustic and thermal data collected during 2014-2015 we were able to assess volume fractions of ash and gas in the eruptive plumes. The small proportion of ash inferred in the plumes confirms estimates from previous, independent, studies, and suggests that these events did not involve significant magma fragmentation in the conduit. The results also agree with the suggestion that sacrificial fragmentation along fault zones in the conduit region, due to shear-induced thermal vesiculation, may be at the origin of such events. Finally, starting in the summer of 2015, our experiment captured the transition to a new phase of activity characterized by vigorous vulcanian-style explosions producing large, ash-rich, plumes and frequent hazardous pyroclastic flows, as well as the formation a large summit crater. We present evidence of this transition in the geophysical and geological data, and discuss its underlying mechanisms within the framework of recent and previous models of volcanic activity at Santiaguito. We conclude that our observations have the potential to considerably advance our understanding of effusive-explosive transitions at lava dome volcanoes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.V43B2869K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.V43B2869K"><span>Monitoring lava dome changes by means of differential DEMs from TanDEM-X interferometry: Examples from Merapi, Indonesia and Volcán de Colima, Mexico</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kubanek, J.; Westerhaus, M.; Heck, B.</p> <p>2013-12-01</p> <p>Estimating the amount of erupted material during a volcanic crisis is one of the major challenges in volcano research. One way to do this and to discriminate between juvenile and non-juvenile fraction is to assess topographic changes before and after an eruption while using area-wide 3D data. LiDAR or other airborne systems may be a good source, but the recording fails when clouds due to volcanic activity obstruct the sight. In addition, costs as well as logistics are high for local observatories. When dealing with dome-building volcanoes, acquiring the data gets further complicated. As the volcano dome can change rapidly in active phases, it is nearly impossible to collect data at the right time. However, when dealing with gross volume change estimates, at least two data sets - taken directly before and after the eruption - are essential. The innovative German Earth observation mission TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurement) is of great importance to overcome some of these problems. The two almost identical radar satellites TerraSAR-X and TanDEM-X fly in a close formation, thus recording images of the same place on the Earth surface at the same time (bistatic mode). As the radar signal penetrates clouds, digital elevation models (DEMs) of the area of investigation can be generated without problems even with cloud cover. A time series analysis of the differential DEMs therefore opens the possibility to assess volume changes at active lava domes. We choose Merapi in Indonesia and Volcán de Colima in Mexico as test sites. Both volcanoes reside in a state of long term effusive eruption, interrupted every few years by phases of dome destruction, generation of pyroclastic flows and deposition of volcanic material. The availability of extensive ground truth data for both test sites further enables to validate the spaceborne data and results. Here, we analyze lava dome changes due to the hazardous Merapi 2010 eruption. We show a series of DEMs derived by TanDEM-X interferometry taken before and after the eruption. Our results reveal that the eruption had led to a topographic change of up to 200 m in the summit area of Merapi. We further show the ability of the TanDEM-X data to observe much smaller topographic changes using Volcán de Colima as second test site. An explosion at the crater rim signaled the end of magma ascent in June 2011. The bistatic TanDEM-X data give important information on this explosion as we can observe topographic changes of up to 20 m and less in the summit area when comparing datasets taken before and after the event. We further analyzed datasets from the beginning of the year 2013 when Colima got active again after a dormant period. Our results indicate that repeated DEMs with great detail and good accuracy are obtainable, enabling a quantitative estimation of volume changes in the summit area of the volcano. As the TanDEM-X mission is an innovative mission, the present study serves as a test to employ data of a new satellite mission in volcano research. An error analysis of the DEMs to evaluate the volume quantifications was therefore also conducted.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1910693P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1910693P"><span>Mt. Etna: rationale and implementation of a Supersite</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Puglisi, Giuseppe</p> <p>2017-04-01</p> <p>Mt. Etna is one of the most active volcanoes on Earth and, in the past few decades, has erupted virtually every year. The volcanism of Mt. Etna results from the interaction between magma ascent in the rather complex plumbing feeding system and the local tectonic regime controlled by the volcano edifice's eastern flank instability, whose driving conditions (e.g., structural setting, tectonic forces) and cause-effect relationships are not yet completely understood. At the surface, the combination of the two factors produces eruptions that might consist of either strongly explosive (e.g., 2002; 2011) and produce volcanic ash plumes likely to disrupt air traffic for hours to weeks (e.g., 5 January 2012), including powerful summit paroxysms in the 2012-2013 time span or lava flows capable of invading the populated sectors, that can threat human property and vital infrastructures. Mt. Etna presents many characteristics that make it prone to be a Geohazard Supersite. The volcano consists of an open-vent system characterised by continuous degassing from the volcano summit craters and frequent eruptive summit and flank eruptions. Eruptions can be of different kinds passing from violent short-lasting explosive events to long-lasting lava output, thus producing different kinds of impacts on the surrounding environment, and especially on the large number of people living around the volcano foot. Over time, the frequency and variety of Mt. Etna's eruptive activity have made the volcano one of the most well-studied and monitored worldwide. At Mt. Etna volcanic activity produces a wide spectrum of signals, spanning from seismic and geodetic to geochemical and radiometric signals, which are tracked in continuous and in real-and quasi-real time by the automatic multi-disciplinary monitoring systems deployed by INGV. The huge amount of ground-based collected data sets enforces the vision of Mt. Etna supersite as a Geohazard Supersite where applying the overarching criteria of the Geohazard supersite initiative of enriching the knowledge on geohazards, and promoting the co-operation between space and in situ data providers and data cross-domain sharing. In particular the Mt. Etna volcano supersite offers the chance to: • achieve new scientific results based on the use of available unprecedented data sets; • develop and transfer timely scientific knowledge on volcanic crises; • develop sustainable long-term Earth observation strategies following eruption. • establish user requirements for the Global Earth Observation System of Systems (GEOSS) The interest of the international volcanological community on Mt. Etna, as well as the growing role as laboratory for hazard assessment during the 20th century, is testified by the inclusion of Mt. Etna in the list of "Decades Volcanoes" identified by the IAVCEI commission during the International Decade for the Natural Disaster Reduction of the UN, and by the great amount of scientific publications (e.g., more than 70 per year, on average, on Mt. Etna over the last ten years). The EC FP7 MED-SUV project allowed making operational the Mt. Etna Supersite by integrating in-situ and EO data sets, by fostering cut-crossing research activities on the internal and superficial volcanic processes, by improving the capability of the hazard assessment and by implementing an e-Infrastructure for the sharing of the data and products.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1811080V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1811080V"><span>Observing changes at Santiaguito Volcano, Guatemala with an Unmanned Aerial Vehicle (UAV)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>von Aulock, Felix W.; Lavallée, Yan; Hornby, Adrian J.; Lamb, Oliver D.; Andrews, Benjamin J.; Kendrick, Jackie E.</p> <p>2016-04-01</p> <p>Santiaguito Volcano (Guatemala) is one of the most active volcanoes in Central America, producing several ash venting explosions per day for almost 100 years. Lahars, lava flows and dome and flank collapses that produce major pyroclastic density currents also present a major hazard to nearby farms and communities. Optical observations of both the vent as well as the lava flow fronts can provide scientists and local monitoring staff with important information on the current state of volcanic activity and hazard. Due to the strong activity, and difficult terrain, unmanned aerial vehicles can help to provide valuable data on the activities of the volcano at a safe distance. We collected a series of images and video footage of A.) The active vent of Caliente and B.) The flow front of the active lava flow and its associated lahar channels, both in May 2015 and in December 2015- January 2016. Images of the crater and the lava flows were used for the reconstruction of 3D terrain models using structure-from-motion. These were supported by still frames from the video recording. Video footage of the summit crater (during two separate ash venting episodes) and the lava flow fronts indicate the following differences in activity during those two field campaigns: A.) - A new breach opened on the east side of the crater rim, possibly during the collapse in November 2015. - The active lava dome is now almost completely covered with ash, only leaving the largest blocks and faults exposed in times without gas venting - A recorded explosive event in December 2015 initiates at subparallel linear faults near the centre of the dome, rather than arcuate or ring faults, with a later, separate, and more ash-laden burst occurring from an off-centre fracture, however, other explosions during the observation period were seen to persist along the ring fault system observed on the lava dome since at least 2007 - suggesting a diversification of explosive activity. B.) - The lava flow fronts did not advance more than a few metres between May and December 2015 . - The width and thickness of the lava flows can be estimated by relative comparison of the 3D models. - Damming of river valleys by the lava flows has established new stream channels that have modified established pathways for the recurring lahars, one of the major hazards of Santiaguito volcano. The preliminary results of this study from two fieldtrips to Santiaguito Volcano are exemplary for the plethora of applications of UAVs in the field of volcano monitoring, and we urge funding agencies and legislative bodies to consider the value of these scientific instruments in future decisions and allocation of funding.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.V23E0513H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.V23E0513H"><span>New Insights into the Seismicity and SO2 Degassing at Cotopaxi Volcano (Ecuador) During the 2015 Unrest and Eruptive Period</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hidalgo, S.; Battaglia, J.</p> <p>2017-12-01</p> <p>Cotopaxi (5897 m) had an unrest and eruption between April and November 2015. Seismic signals and SO2 emissions were recorded by the monitoring network of the Instituto Geofísico. The network includes 11 seismic stations, 6 broad band and 5 short period; and 4 NOVAC-Type 1 DOAS permanent instruments.We reviewed the seismic records to better understand the link between seismicity and SO2 emissions. Transient events detected include Volcano-Tectonic (VT), Long-Period (LP) events and Explosion Quakes (EQ), but also Ice Quakes (IQ) with various spectral signatures related to the glacier covering the volcano summit. An event-per-event exhaustive identification is, however, impossible because of the very large number of events and the wide range of signals, with variable spectral characteristics. Therefore, to identify the different types of events activated previous and during the eruption, we choose an approach based on the search of families of repeating events. Looking at the temporal evolution of these families, we determined 4 characteristic types. The first and more frequent, Type 1, is mainly composed by IQ. Type 2, mainly LPs appeared only in April and May 2015. Interestingly, its rate of occurrence starts increasing the first days of April, is maximum about mid-May when SO2 appears and then progressively drops to totally stop on June 4, replaced by tremor. Since then, and until the hydromagmatic explosions opening the system, SO2 emissions between 3000 and 5000 t/day were directly linked to seismic tremor. Type 3 families, are dominated by VTs, and are only active on 13 and 14 August, before and during the hydromagmatic explosions. These events should be considered as short term seismic precursors. Type 4 families starts at the beginning of September and included only few VTs. Nevertheless, since September, most of the observed events belong to Type 1 families, mainly IQ, hence the seismicity related to volcanic activity after the hydromagmatic explosions was mostly tremor. The post-eruptive tremor was accompanied by ash and gas emissions with SO2 fluxes oscillating according to the median seismic amplitude of the signal. Magma volume estimated on the basis of the 470 kt of SO2 measured during unrest and eruption exceeds in more than 99% the total volume of erupted solid material.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995GMS....92...81L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995GMS....92...81L"><span>Mauna Loa eruptive history—The preliminary radiocarbon record</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lockwood, John P.</p> <p></p> <p>Radiocarbon dating of charcoal from beneath lava flows of Mauna Loa has provided the most detailed prehistoric eruptive chronology of any volcano on Earth. Three hundred and fifty-five 14C dates have been reviewed, stratigraphically contradictory dates have been rejected, and multiple dates on single flows averaged to give "reliable" ages on 170 separate lava flows (about 35% of the total number of prehistoric Mauna Loa flows mapped to date). The distribution of these ages has revealed fundamental variations in the time and place of Mauna Loa eruptive activity, particularly for Holocene time. As lava flow activity from Mauna Loa's summit waxes, activity on the rift zones wanes. A cyclic model is proposed which involves a period of concentrated summit shield-building activity associated with long-lived lava lakes and frequent overflows of pahoehoe lavas on the north and southeast flanks. At this time, compressive stresses across Mauna Loa's rift zones are relatively high, inhibiting eruptions in these areas. This period is then followed by a relaxation of stresses across Mauna Loa's rift zones and a long period of frequent rift zone eruptions as magma migrates downrift. This change of eruptive style is marked by summit caldera collapse (possibly associated with massive eruptions of picritic lavas low on the rift zones). Concurrent with this increased rift zone activity, the summit caldera is gradually filled by repeated summit eruptions, stress across the rift zones increases, magma rises more easily to the summit, rift activity wanes, and the cycle repeats itself. Two such cycles are suggested within the late Holocene, each lasting 1,500-2,000 years. Earlier evidence for such cycles is obscure. Mauna Loa appears to have been quiescent between 6-7 ka, for unknown reasons. A period of increased eruptive activity marked the period 8-11 ka, coincident with the Pleistocene-Holocene boundary. Other volcanoes on the Island of Hawaii for which (limited) radiocarbon dating are available show no evidence of similar cyclicity or repose. Mauna Loa may be presently nearing the end of a thousand-year-long period of increased rift zone activity, and sustained summit eruptions may characterize the volcano's most typical behavior in the millennium to come. Such a shift could eventually alter the nature of volcanic risk for future populations on Hawaii.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.V43A3130D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.V43A3130D"><span>Observing changes at Santiaguito Volcano, Guatemala with an Unmanned Aerial Vehicle (UAV)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>De Angelis, S.; von Aulock, F.; Lavallée, Y.; Hornby, A. J.; Kennedy, B.; Lamb, O. D.; Kendrick, J. E.</p> <p>2016-12-01</p> <p>Santiaguito Volcano (Guatemala) is one of the most active volcanoes in Central America, producing several ash venting explosions per day for almost 100 years. Lahars, lava flows and dome and flank collapses that produce major pyroclastic density currents also present a major hazard to nearby farms and communities. Optical observations of both the vent as well as the lava flow fronts can provide scientists and local monitoring staff with important information on the current state of volcanic activity and hazard. Due to the strong activity, and difficult terrain, unmanned aerial vehicles can help to provide valuable data on the activities of the volcano at a safe distance. We collected a series of images and video footage of the active vent of Caliente and the flow front of the active lava flow and its associated lahar channels, both in May 2015 and in December 2015- January 2016. Images of the crater and the lava flows were used for the reconstruction of 3D terrain models using structure-from-motion. These models can be used to constrain topographical changes and distribution of ballistics via cloud comparisons. The preliminary data of aerial images and videos of the summit crater (during two separate ash venting episodes) and the lava flow fronts indicate the following differences in activity during those two field campaigns: - A recorded explosive event in December 2015 initiates at subparallel linear faults near the centre of the dome, with a later, separate, and more ash-laden burst occurring from an off-centre fracture. - A comparison of the point clouds before and after a degassing explosion shows minor subsidence of the dome surface and the formation of several small craters at the main venting locations. - The lava flow fronts did not advance more than a few meters between May and December 2015. - Damming of river valleys by the lava flows has established new stream channels that have modified established pathways for the recurring lahars, one of the major hazards of Santiaguito volcano. The preliminary results of this study from two fieldtrips to Santiaguito Volcano are exemplary for the plethora of applications of UAVs in the field of volcano monitoring, and we urge funding agencies and legislative bodies to consider the value of these scientific instruments in future decisions and allocation of funding.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.8575O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.8575O"><span>Volcano Observations Using an Unmanned Autonomous Helicopter : seismic and GPS observations near the active summit area of Sakurajima and Kirishima volcano, Japan</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ohminato, T.; Kaneko, T.; Koyama, T.; Watanabe, A.; Takeo, M.; Iguchi, M.; Honda, Y.</p> <p>2012-04-01</p> <p>Observations in the vicinity of summit area of active volcanoes are very important from various viewpoints such as understanding physical processes in the volcanic conduit. It is, however, highly difficult to install observation sensors near active vents because of the risk of sudden eruptions. We have been developing a safe volcano observation system based on an unmanned aerial vehicle (UAV). As an UAV, we adopted an unmanned autonomous helicopter manufactured by Yamaha-Motor Co., Ltd. We have also developed earthquake observation modules and GPS receiver modules that are exclusively designed for UAV installation at summit areas of active volcanoes. These modules are light weight, compact size, and solar powered. For data transmission, a commercial cellular-phone network is used. Our first application of the sensor installation by the UAV is Sakurajima, one of the most active volcanos in Japan. In November 2009, 2010, and 2011, we installed up to four seismic sensors within 2km from the active summit crater. In the 2010 and 2011 operations, we succeeded in pulling up and collecting the sensor modules by using the UAV. In the 2011 experiment, we installed two GPS receivers near the summit area of Sakurajima volcano. We also applied the UAV installation to another active volcano, Shinmoedake in Kirishima volcano group. Since the sub-plinian eruption in February 2011, entering the area 3km from the summit of Shinmoe-dake has been prohibited. In May and November 2011, we installed seismic sensors and GPS receivers in the off-limit zone. Although the ground coupling of the seismic modules is not perfect due to the way they are installed, the signal-to-noise ratio of the seismic signals recorded by these modules is fairly good. Despite the low antenna height of 50 cm from the ground surface, the location errors in horizontal and vertical GPS components are 1cm and 3cm, respectively. For seismic signals associated with eruptions at Sakurajima from November 2010 to November 2011, we measure temporal variation of the amplitude ratio among the summit stations. In order to correct the amplitude variation due to the source amplitude variation, the amplitude of the recorded signals are normalized by using the amplitude of a permanent station, located on the western flank of Sakurajima 5km from the summit. The daily average of the normalized amplitude ratios among the summit stations shows clear temporal variation. The amplitude ratio variation can be classified to three stages. In the first stage, the amplitude ratios among the summit stations are nearly constant. The 2nd stage is characterized by a gradual increase in the amplitude ratio. The third stage is slightly difficult to define but we can say that the amplitude ratios are almost constant with fluctuations larger than that in the first stage. These changes strongly suggest a change in the source depth, probably migration of the source to the shallower portion in the volcanic conduit. Small change in the source position would have been observed as a big change in the observed amplitude ratio due to the closeness of the sensors to the source.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JVGR..337...98W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JVGR..337...98W"><span>Magmatic degassing, lava dome extrusion, and explosions from Mount Cleveland volcano, Alaska, 2011-2015: Insight into the continuous nature of volcanic activity over multi-year timescales</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Werner, Cynthia; Kern, Christoph; Coppola, Diego; Lyons, John J.; Kelly, Peter J.; Wallace, Kristi L.; Schneider, David J.; Wessels, Rick L.</p> <p>2017-05-01</p> <p>Mount Cleveland volcano (1730 m) is one of the most active volcanoes in the Aleutian arc, Alaska, but heightened activity is rarely accompanied by geophysical signals, which makes interpretation of the activity difficult. In this study, we combine volcanic gas emissions measured for the first time in August 2015 with longer-term measurements of thermal output and lava extrusion rates between 2011 and 2015 calculated from MODIS satellite data with the aim to develop a better understanding of the nature of volcanic activity at Mount Cleveland. Degassing measurements were made in the month following two explosive events (21 July and 7 August 2015) and during a period of new dome growth in the summit crater. SO2 emission rates ranged from 400 to 860 t d- 1 and CO2/SO2 ratios were < 3, consistent with the presence of shallow magma in the conduit and the observed growth of a new lava dome. Thermal anomalies derived from MODIS data from 2011 to 2015 had an average repose time of only 4 days, pointing to the continuous nature of volcanic activity at this volcano. Rapid increases in the cumulative thermal output were often coincident with visual confirmation of dome growth or accumulations of tephra in the crater. The average rate of lava extrusion calculated for 9 periods of rapid increase in thermal output was 0.28 m3 s- 1, and the total volume extruded from 2011 to 2015 was 1.9-5.8 Mm3. The thermal output from the lava extrusion events only accounts for roughly half of the thermal budget, suggesting a continued presence of shallow magma in the upper conduit, likely driven by convection. Axisymmetric dome morphology and occasional drain back of lava into the conduit suggests low-viscosity magmas drive volcanism at Mount Cleveland. It follows also that only small overpressures can be maintained given the small domes and fluid magmas, which is consistent with the low explosivity of most of Mount Cleveland's eruptions. Changes between phases of dome growth and explosive activity are somewhat unpredictable and likely result from plugs that are related to the dome obtaining a critical dimension, or from small variations in the magma ascent rate that lead to crystallization-induced blockages in the upper conduit, thereby reducing the ability of magma to degas. We suggest the small magma volumes, slow ascent rates, and low magma viscosity lead to the overall lack of anomalous geophysical signals prior to eruptions, and that more continuous volcanic degassing measurements might lead to more successful eruption forecasting at this continuously-active open-vent volcano.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70192603','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70192603"><span>Magmatic degassing, lava dome extrusion, and explosions from Mount Cleveland volcano, Alaska, 2011–2015: Insight into the continuous nature of volcanic activity over multi-year timescales</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Werner, Cynthia; Kern, Christoph; Coppola, Diego; Lyons, John; Kelly, Peter; Wallace, Kristi; Schneider, David; Wessels, Rick</p> <p>2017-01-01</p> <p>Mount Cleveland volcano (1730 m) is one of the most active volcanoes in the Aleutian arc, Alaska, but heightened activity is rarely accompanied by geophysical signals, which makes interpretation of the activity difficult. In this study, we combine volcanic gas emissions measured for the first time in August 2015 with longer-term measurements of thermal output and lava extrusion rates between 2011 and 2015 calculated from MODIS satellite data with the aim to develop a better understanding of the nature of volcanic activity at Mount Cleveland. Degassing measurements were made in the month following two explosive events (21 July and 7 August 2015) and during a period of new dome growth in the summit crater. SO2 emission rates ranged from 400 to 860 t d− 1 and CO2/SO2 ratios were < 3, consistent with the presence of shallow magma in the conduit and the observed growth of a new lava dome. Thermal anomalies derived from MODIS data from 2011 to 2015 had an average repose time of only 4 days, pointing to the continuous nature of volcanic activity at this volcano. Rapid increases in the cumulative thermal output were often coincident with visual confirmation of dome growth or accumulations of tephra in the crater. The average rate of lava extrusion calculated for 9 periods of rapid increase in thermal output was 0.28 m3 s− 1, and the total volume extruded from 2011 to 2015 was 1.9–5.8 Mm3. The thermal output from the lava extrusion events only accounts for roughly half of the thermal budget, suggesting a continued presence of shallow magma in the upper conduit, likely driven by convection. Axisymmetric dome morphology and occasional drain back of lava into the conduit suggests low-viscosity magmas drive volcanism at Mount Cleveland. It follows also that only small overpressures can be maintained given the small domes and fluid magmas, which is consistent with the low explosivity of most of Mount Cleveland's eruptions. Changes between phases of dome growth and explosive activity are somewhat unpredictable and likely result from plugs that are related to the dome obtaining a critical dimension, or from small variations in the magma ascent rate that lead to crystallization-induced blockages in the upper conduit, thereby reducing the ability of magma to degas. We suggest the small magma volumes, slow ascent rates, and low magma viscosity lead to the overall lack of anomalous geophysical signals prior to eruptions, and that more continuous volcanic degassing measurements might lead to more successful eruption forecasting at this continuously-active open-vent volcano.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.V52C..04P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.V52C..04P"><span>Controls on lava lake level at Halema`uma`u Crater, Kilauea Volcano</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Patrick, M. R.; Orr, T. R.</p> <p>2013-12-01</p> <p>Lava level is a fundamental measure of lava lake activity, but very little continuous long-term data exist worldwide to explore this aspect of lava lake behavior. The ongoing summit eruption at Kilauea Volcano began in 2008 and is characterized by an active lava lake within the eruptive vent. Lava level has been measured nearly continuously at Kilauea for several years using a combination of webcam images, laser rangefinder, and terrestrial LIDAR. Fluctuations in lava level have been a common aspect of the eruption and occur over several timescales. At the shortest timescale, the lava lake level can change over seconds to hours owing to two observed shallow gas-related processes. First, gas pistoning is common and is driven by episodic gas accumulation and release from the surface of the lava lake, causing the lava level to rise and fall by up to 20 m. Second, rockfalls into the lake trigger abrupt gas release, and lava level may drop as much as 10 m as a result. Over days, cyclic changes in lava level closely track cycles of deflation-inflation (DI) deformation events at the summit, leading to level changes up to 50 m. Rift zone intrusions have caused large (up to 140 m) drops in lava level over several days. On the timescale of weeks to months, the lava level follows the long-term inflation and deflation of the summit region, resulting in level changes up to 140 m. The remarkable correlation between lava level and deflation-inflation cycles, as well as the long-term deformation of the summit region, indicates that the lava lake acts as a reliable 'piezometer' (a measure of liquid pressure in the magma plumbing system); therefore, assessments of summit pressurization (and rift zone eruption potential) can now be carried out with the naked eye. The summit lava lake level is closely mirrored by the lava level within Pu`u `O`o crater, the vent area for the 30-year-long eruption on Kilauea's east rift zone, which is 20 km downrift of the summit. The coupling of these lava levels implies an efficient hydraulic connection between the summit and east rift zone vents. This connection has been indicated previously with geophysical data and is reinforced in a new quantitative manner with lava level data. Lastly, the current lava level at the summit is significantly lower than the mean level measured in the crater during continuous lava lake activity in the early 1900s. This is probably because the ongoing eruption at Pu`u `O`o 'taps' the magma supplied to the summit reservoir. Should the Pu`u `O`o eruption stop, the lava level at the summit would certainly rise in response. The precise correspondence between lava lake level and deformation of the summit implies that the lake level is a good indication of the pressure state of the magma reservoir. Tracking lava level over time may therefore provide an indication of the potential for future changes in eruptive activity. Such an observation has clear relevance for monitoring analogous open-vent basaltic volcanoes, especially where other measures of volcanic activity, like seismic or deformation measurements, may be lacking.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA583085','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA583085"><span>Characterization of Firing Range Soil from Camp Edwards, MA, and the Efficacy of Acid and Alkaline Hydrolysis for the Remediation of M1 105mm M67 Propellant</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2013-06-01</p> <p>method is intended for trace analysis of explosives and propellant residues by high performance liquid chromatography (HPLC) using an ultraviolet (UV...detector set at 254 nm. The HPLC used for this analysis was a Dionex Summit System with a UV detector equipped with Dionex E1 and E2 columns...Ca(OH)2) and sodium hydroxide (NaOH) were evaluated as sources of hydroxide ion for the alkaline hydrolysis of M1 propellant in soil from Camp</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2837420','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2837420"><span>The Science of Eliminating Health Disparities: Summary and Analysis of the NIH Summit Recommendations</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rhee, Kyu B.; Williams, Kester; Sanchez, Idalia; Sy, Francisco S.; Stinson, Nathaniel; Ruffin, John</p> <p>2010-01-01</p> <p>In December 2008, the National Institutes of Health (NIH) sponsored the first NIH Summit showcasing its investment and contribution to health disparities research and unveiling a framework for moving this important field forward. The Summit, titled “The Science of Eliminating Health Disparities,” drew on extensive experience of experts leading health disparities research transformation in diverse fields. The Summit also provided a historic educational opportunity to contribute to health care reform. The theme, addressing disparities through integration of science, practice, and policy, introduced a paradigm for advancing research through transformational, translational, and transdisciplinary research. Engaging active participation throughout the Summit generated recommendations bridging science, practice, and policy, including action on social determinants of health, community engagement, broad partnerships, capacity-building, and media outreach. PMID:20147660</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70019506','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70019506"><span>Evidence for water influx from a caldera lake during the explosive hydromagmatic eruption of 1790, Kilauea volcano, Hawaii</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Mastin, L.G.</p> <p>1997-01-01</p> <p>In 1790 a major hydromagmatic eruption at the summit of Kilauea volcano, Hawaii, deposited up to 10 m of pyroclastic fall and surge deposits and killed several dozen Hawaiian natives who were crossing the island. Previous studies have hypothesized that the explosivity of this eruption was due to the influx of groundwater into the conduit and mixing of the groundwater with ascending magma. This study proposes that surface water, not groundwater, was the agent responsible for the explosiveness of the eruption. That is, a lake or pond may have existed in the caldera in 1790 and explosions may have taken place when magma ascended into the lake from below. That assertion is based on two lines of evidence: (1) high vesicularity (averaging 73% of more than 3000 lapilli) and high vesicle number density (105-107 cm-3 melt) of pumice clasts suggest that some phases of the eruption involved vigorous, sustained magma ascent; and (2) numerical calculations suggest that under most circumstances, hydrostatic pressure would not be sufficient to drive water into the eruptive conduit during vigorous magma ascent unless the water table were above the ground surface. These results are supported by historical data on the rate of infilling of the caldera floor during the early 1800s. When extrapolated back to 1790, they suggest that the caldera floor was below the water table.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1510478L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1510478L"><span>Recent SO2 camera and OP-FTIR field measurements in Mexico and Guatemala</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>La Spina, Alessandro; Salerno, Giuseppe; Burton, Michael</p> <p>2013-04-01</p> <p>Between 22 and 30 November 2012 a field campaign was carried out at Mexico and Guatemala with the objectives of state the volcanic gas composition and flux fingerprints of Popocatepetl, Santiaguito, Fuego and Pacaya by exploiting simultaneously UV-camera and FTIR measurements. Gases were measured remotely using instruments sensitive to ultraviolet and infrared radiation (UV spectrometer, SO2-camera and OP-FTIR). Data collection depended on the requirements of the methodology, weather condition and eruptive stage of the volcanoes. OP-FTIR measurements were carried out using the MIDAC interferometer with 0.5 cm-1 resolution. Spectra were collected in solar occultation mode in which the Sun acts as an infrared source and the volcanic plume is interposed between the Sun and the spectrometer. At Santiaguito spectra were also collected in passive mode using the lava flow as a radiation source. The SO2-camera used for this study was a dual camera system consisting of two QS Imaging 640s cameras. Each of the two cameras was outfitted with two quartz 25mm lens, coupled with two band-pass filters centred at 310nm and at 330nm. The imaging system was managed by a custom-made software developed in LabView. The UV-camera system was coupled with a USB2000+ spectrometer connected to a QP1000-2-SR 1000 micron optical fiber with a 74-UV collimating lens. For calibration of plume imagery, images of five quartz cells containing known concentration path-lengths of SO2 were taken at the end of each sampling. Between 22 and 23 November 2012 UV-camera and FTIR observations were carried out at Popocatepetl. During the time of our observation, the volcano was characterised by pulsing degassing from the summit crater forming a whitish plume that dispersed rapidly in the atmosphere according to wind direction and speed. Data were collected from the Observatorio Atmosférico Altzomoni (Universidad Nacional Autónoma de México) at 4000 metre a.s.l. and at a distance of ~12 km from the volcano summit. SO2 camera observations were made for ~30 and 130 minutes on the 22 and 23 November, respectively, with a sampling rate of ~7 seconds. FTIR measurements were carried out for 20 and 15 minutes on 22 and 23 November. At Santiaguito volcano, we carried out volcanic gas measurements on 27 and 28 November 2012. During the period of our observations the volcano activity was characterised by lava flow extrusion on the S flank of dome edifice. Occasionally, incandescent blocks detached from the lava flow front rolling onto the dome flanks. During the time of our survey the explosive activity was low frequency (every ~5 - 6 hours). We observed a persistent and sustained degassing plume was observed occasionally polluted by ash. However, on 28 November at 5:25 local time, a violent pyroclastic flow occurred generating an ash-plume that rose ~5 km passing Santa Maria's summit and spreading ~30 km south. SO2 camera and FTIR data were simultaneously collected on 27 November from El Mirador at a distance of ~2 Km from the lava-dome. Data were collected for ~75 and ~90 minutes for SO2-camera and FTIR, respectively. On 28 November, due to the pyroclastic flow event, only distal solar occultation FTIR measurements and open-path UV spectra (using a USB spectrometer) were collected from the west flank of Santa Maria volcano. Both UV and IR spectra were recorded for ~60 minutes Ash released by the pyroclastic flow was sampled from a distance of 6.5 km from the volcano collecting the fallout products along a 60 minute time interval Data from the volcanic plumes of Pacaya and Fuego were collected on 29 and 30 November 2012. During our survey the eruptive activity of Pacaya consisted of weak puffing from the summit crater, while Fuego showed a weak outgassing occasionally interrupted by explosion from its summit crater. In both days, we carried out only SO2 camera measurements due to the poor weather conditions which prevented solar FTIR measurments. At both volcanoes, UV images were taken for a period of ~45 minutes from a distance of ~ 3 km and ~ 10 km, respectively. In this paper we summarise the results from the field campaign and interpret the gas observations in light of the current activity of each volcanic source.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss019e005286.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss019e005286.html"><span>Earth Observations by the Expedition 19 crew</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2009-04-08</p> <p>ISS019-E-005286 (8 April 2009) --- Mount Fuji, Japan is featured in this image photographed by an Expedition 19 crew member on the International Space Station. The 3,776 meters high Mount Fuji volcano, located on the island of Honshu in Japan, is one of the world?s classic examples of a stratovolcano. The volcano?s steep, conical profile is the result of numerous interlayered lava flows and explosive eruption products ? such as ash, cinders, and volcanic bombs ? building up the volcano over time. The steep profile is possible because of the relatively high viscosity of the volcanic rocks typically associated with stratovolcanoes. This leads to thick sequences of lava flows near the eruptive vent that build the cone structure, rather than low viscosity flows that spread out over the landscape and build lower-profile shield volcanoes. According to scientists, Mount Fuji, or Fuji-san in Japan, is actually comprised of several overlapping volcanoes that began erupting in the Pleistocene Epoch (1.8 million to approximately 10,000 years ago). Scientists believe that the currently active volcano, known as Younger Fuji, began forming approximately 11,000 to 8,000 years ago. The most recent explosive activity occurred in 1707, creating Hoei Crater on the southeastern flank of the volcano (center). This eruption deposited ash on Edo (present-day Tokyo) located 95 kilometers to the northeast. While there have been no further eruptions of Mount Fuji, steam was observed at the summit during 1780?1820, and the volcano is considered active. This oblique photograph illustrates the snow-covered southeastern flank of the volcano; the northeastern flank can be seen here. A representation of the topography of Mt. Fuji and its surroundings can be viewed here.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24126286','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24126286"><span>A large hydrothermal reservoir beneath Taal Volcano (Philippines) revealed by magnetotelluric observations and its implications to the volcanic activity.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Alanis, Paul K B; Yamaya, Yusuke; Takeuchi, Akihiro; Sasai, Yoichi; Okada, Yoshihiro; Nagao, Toshiyasu</p> <p>2013-01-01</p> <p>Taal Volcano is one of the most active volcanoes in the Philippines. The magnetotelluric 3D forward analyses indicate the existence of a large high resistivity anomaly (∼100 Ω·m) with a volume of at least 3 km×3 km×3 km, which is capped by a conductive layer (∼10 Ω·m), beneath the Main Crater. This high resistivity anomaly is hypothesized to be a large hydrothermal reservoir, consisting of the aggregate of interconnected cracks in rigid and dense host rocks, which are filled with hydrothermal fluids coming from a magma batch below the reservoir. The hydrothermal fluids are considered partly in gas phase and liquid phase. The presence of such a large hydrothermal reservoir and the stagnant magma below may have influences on the volcano's activity. Two possibilities are presented. First, the 30 January 1911 explosion event was a magmatic hydrothermal eruption rather than a base-surge associated with a phreato-magmatic eruption. Second, the earlier proposed four eruption series may be better interpreted by two cycles, each consisting of series of summit and flank eruptions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3832744','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3832744"><span>A large hydrothermal reservoir beneath Taal Volcano (Philippines) revealed by magnetotelluric observations and its implications to the volcanic activity</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>ALANIS, Paul K. B.; YAMAYA, Yusuke; TAKEUCHI, Akihiro; SASAI, Yoichi; OKADA, Yoshihiro; NAGAO, Toshiyasu</p> <p>2013-01-01</p> <p>Taal Volcano is one of the most active volcanoes in the Philippines. The magnetotelluric 3D forward analyses indicate the existence of a large high resistivity anomaly (∼100 Ω·m) with a volume of at least 3 km × 3 km × 3 km, which is capped by a conductive layer (∼10 Ω·m), beneath the Main Crater. This high resistivity anomaly is hypothesized to be a large hydrothermal reservoir, consisting of the aggregate of interconnected cracks in rigid and dense host rocks, which are filled with hydrothermal fluids coming from a magma batch below the reservoir. The hydrothermal fluids are considered partly in gas phase and liquid phase. The presence of such a large hydrothermal reservoir and the stagnant magma below may have influences on the volcano’s activity. Two possibilities are presented. First, the 30 January 1911 explosion event was a magmatic hydrothermal eruption rather than a base-surge associated with a phreato-magmatic eruption. Second, the earlier proposed four eruption series may be better interpreted by two cycles, each consisting of series of summit and flank eruptions. PMID:24126286</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss020e021140.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss020e021140.html"><span>Earth Observation taken by the Expedition 20 crew</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2009-07-15</p> <p>ISS020-E-021140 (15 July 2009) --- Teide Volcano on the Canary Islands of Spain is featured in this image photographed by an Expedition 20 crew member on the International Space Station. This detailed photograph features two stratovolcanoes ? Pico de Teide and Pico Viejo ? located on Tenerife Island, part of the Canary Islands of Spain. Stratovolcanoes are steep-sided; typically conical structures formed by interlayered lavas and fragmented rock material from explosive eruptions. Pico de Teide has a relatively sharp peak, whereas an explosion crater forms the summit of Pico Viejo. The two stratovolcanoes formed within an even larger volcanic structure known as the Las Ca?adas caldera ? a large collapse depression typically formed when a major eruption completely empties the underlying magma chamber of a volcano. The last eruption of Teide occurred in 1909. NASA scientists point out sinuous flow levees marking individual lava flows. The scientists consider the flow levees as perhaps the most striking volcanic features visible in the image. Flow levees are formed when the outer edges of a channelized lava flow cool and harden while the still-molten interior continues to flow downhill ? numerous examples radiate outwards from the peaks of both Pico de Teide and Pico Viejo. Brown to tan overlapping lava flows and domes are visible to the east-southeast of the Teide stratovolcano. Increased seismicity, carbon dioxide emissions, and fumarolic activity within the Las Ca?adas caldera and along the northwestern flanks of the volcano were observed in 2004. Monitoring of the volcano to detect renewal of activity is ongoing.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70012877','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70012877"><span>Variations in tilt rate and harmonic tremor amplitude during the January-August 1983 east rift eruptions of Kilauea Volcano, Hawaii</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Dvorak, J.J.; Okamura, A.T.</p> <p>1985-01-01</p> <p>During January-August 1983, a network of telemetered tiltmeters and seismometers recorded detailed temporal changes associated with seven major eruptive phases along the east rift of Kilauea Volcano, Hawaii. Each eruptive phase was accompanied by subsidence of the summit region and followed by reinflation of the summit to approximately the same level before renewal of eruptive activity. The cyclic summit tilt pattern and the absence of measurable tilt changes near the eruptive site suggest that conditions in the summit region controlled the timing of the last six eruptive phases. The rate of summit subsidence progressively increased from one eruptive phase to the next during the last six phases; the amplitude of harmonic tremor increased during the last four phases. The increases in subsidence rate and in tremor amplitude suggest that frequent periods of magma movement have reduced the flow resistance of the conduit system between the summit and the rift zone. ?? 1985.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMNH41E..03O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMNH41E..03O"><span>Observations at Kuchinoerabu-jima volcano, southern Kyushu, Japan, by using unmanned helicopter</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ohminato, T.; Kaneko, T.; Koyama, T.; Watanabe, A.; Kanda, W.; Tameguri, T.; Kazahaya, R.</p> <p>2015-12-01</p> <p>Kuchinoerabu-jima, volcano is a volcanic island located southern Kyushu, Japan. In 3 August, 2014, a small eruption at active summit crater, Shin-dake, destroyed all the observation stations near the summit. Since then, this volcano was only poorly monitored. After the eruption, entering within 2km from Shin-dake crater was strictly prohibited and thus it was impossible to fix summit stations on site. In April, 2015, we conducted seismic sensor installation by using unmanned helicopter (RMAX-G1 manufactured by Yamaha) so as to reestablish the seismic monitoring network near the summit area. We installed four seismic stations in the summit area. We also conducted various types of near-summit observations including an aero-magnetic measurement over the summit area, taking visual and infra-red images from low altitude, and volcanic gas sampling. We present preliminary results of the near summit observations using unmanned helicopter. The light-weight (5kg) and solar-powered seismic stations were designed exclusively for helicopter installation. They transmit seismic data every 10 minutes by using mobile data communication network. We could install them within 500m from the summit crater on 17, April. On 29 May, Shin-dake crater erupted again and the newly installed seismic stations were all destroyed by this eruption. The seismic stations could transmit data until just before the eruption. These data made us possible to evaluate the change in seismic activity leading up to the eruption. An aero-magnetic survey was conducted on 17 and 18 April. The flight altitude was between 100m and 150m above the ground (i.e a draped magnetic survey) . Path interval is 100m and the total flight path length is 80km. The magnetic intensity data were converted to magnetization of the edifice of Shin-dake. Comparison between the result this time with that obtained in 2001 shows demagnetization near the summit area. Temperature measurement over the summit area detected 368ºC at the fissure on the western flank. Chemical composition of the volcanic gas was measured. Maximum concentration of SO2 was 28ppm and the apparent equilibrium temperature estimated from the gas composition was 550 ºC. CO2/SO2 ratio did not change significantly but a large variation in SO2/H2S ratio was observed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100036738','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100036738"><span>Atrial Arrhythmias in Astronauts - Summary of a NASA Summit</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Barr, Yael R.; Watkins, Sharmila D.; Polk, J. D.</p> <p>2010-01-01</p> <p>Background and Problem Definition: To evaluate NASA s current standards and practices related to atrial arrhythmias in astronauts, Space Medicine s Advanced Projects Section at the Johnson Space Center was tasked with organizing a summit to discuss the approach to atrial arrhythmias in the astronaut cohort. Since 1959, 11 cases of atrial fibrillation, atrial flutter, or supraventricular tachycardia have been recorded among active corps crewmembers. Most of the cases were paroxysmal, although a few were sustained. While most of the affected crewmembers were asymptomatic, those slated for long-duration space flight underwent radiofrequency ablation treatment to prevent further episodes of the arrhythmia. The summit was convened to solicit expert opinion on screening, diagnosis, and treatment options, to identify gaps in knowledge, and to propose relevant research initiatives. Summit Meeting Objectives: The Atrial Arrhythmia Summit brought together a panel of six cardiologists, including nationally and internationally renowned leaders in cardiac electrophysiology, exercise physiology, and space flight cardiovascular physiology. The primary objectives of the summit discussions were to evaluate cases of atrial arrhythmia in the astronaut population, to understand the factors that may predispose an individual to this condition, to understand NASA s current capabilities for screening, diagnosis, and treatment, to discuss the risks associated with treatment of crewmembers assigned to long-duration missions or extravehicular activities, and to discuss recommendations for prevention or management of future cases. Summary of Recommendations: The summit panel s recommendations were grouped into seven categories: Epidemiology, Screening, Standards and Selection, Treatment of Atrial Fibrillation Manifesting Preflight, Atrial Fibrillation during Flight, Prevention of Atrial Fibrillation, and Future Research</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4373145','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4373145"><span>Decrypting geophysical signals at Stromboli Volcano (Italy): Integration of seismic and Ground-Based InSAR displacement data</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Di Traglia, F; Cauchie, L; Casagli, N; Saccorotti, G</p> <p>2014-01-01</p> <p>We present the integration of seismic and Ground-Based Interferometric Synthetic Aperture Radar system (GBInSAR) displacement data at Stromboli Volcano. Ground deformation in the area of summit vents is positively correlated with both seismic tremor amplitude and cumulative amplitudes of very long period (VLP) signals associated with Strombolian explosions. Changes in VLP amplitudes precede by a few days the variations in ground deformation and seismic tremor. We propose a model where the arrival of fresh, gas-rich magma from depth enhances gas slug formation, promoting convection and gas transfer throughout the conduit system. At the shallowest portion of the conduit, an increase in volatile content causes a density decrease, expansion of the magmatic column and augmented degassing activity, which respectively induce inflation of the conduit, and increased tremor amplitudes. The temporal delay between increase of VLP and tremor amplitudes/conduit inflation can be interpreted in terms of the different timescales characterizing bulk gas transfer versus slug formation and ascent. PMID:25821278</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25821278','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25821278"><span>Decrypting geophysical signals at Stromboli Volcano (Italy): Integration of seismic and Ground-Based InSAR displacement data.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Di Traglia, F; Cauchie, L; Casagli, N; Saccorotti, G</p> <p>2014-04-28</p> <p>We present the integration of seismic and Ground-Based Interferometric Synthetic Aperture Radar system (GBInSAR) displacement data at Stromboli Volcano. Ground deformation in the area of summit vents is positively correlated with both seismic tremor amplitude and cumulative amplitudes of very long period (VLP) signals associated with Strombolian explosions. Changes in VLP amplitudes precede by a few days the variations in ground deformation and seismic tremor. We propose a model where the arrival of fresh, gas-rich magma from depth enhances gas slug formation, promoting convection and gas transfer throughout the conduit system. At the shallowest portion of the conduit, an increase in volatile content causes a density decrease, expansion of the magmatic column and augmented degassing activity, which respectively induce inflation of the conduit, and increased tremor amplitudes. The temporal delay between increase of VLP and tremor amplitudes/conduit inflation can be interpreted in terms of the different timescales characterizing bulk gas transfer versus slug formation and ascent.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.cancer.gov/news-events/cancer-currents-blog/2016/moonshot-summit','NCI'); return false;" href="https://www.cancer.gov/news-events/cancer-currents-blog/2016/moonshot-summit"><span>The Cancer Moonshot Summit: Reaching New Heights</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.cancer.gov">Cancer.gov</a></p> <p></p> <p></p> <p>An NCI Cancer Currents blog from acting NCI Director Dr. Doug Lowy on the Cancer Moonshot national summit hosted by Vice President Joe Biden in Washington, D.C., including a summary of the NCI-related activities stimulated by the Cancer Moonshot.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011GeoRL..38.3302D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011GeoRL..38.3302D"><span>Determining the seismic source mechanism and location for an explosive eruption with limited observational data: Augustine Volcano, Alaska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dawson, Phillip B.; Chouet, Bernard A.; Power, John</p> <p>2011-02-01</p> <p>Waveform inversions of the very-long-period components of the seismic wavefield produced by an explosive eruption that occurred on 11 January, 2006 at Augustine Volcano, Alaska constrain the seismic source location to near sea level beneath the summit of the volcano. The calculated moment tensors indicate the presence of a volumetric source mechanism. Systematic reconstruction of the source mechanism shows the source consists of a sill intersected by either a sub-vertical east-west trending dike or a sub-vertical pipe and a weak single force. The trend of the dike may be controlled by the east-west trending Augustine-Seldovia arch. The data from the network of broadband sensors is limited to fourteen seismic traces, and synthetic modeling confirms the ability of the network to recover the source mechanism. The synthetic modeling also provides a guide to the expected capability of a broadband network to resolve very-long-period source mechanisms, particularly when confronted with limited observational data.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2003/0112/pdf/of03-112.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2003/0112/pdf/of03-112.pdf"><span>Preliminary volcano-hazard assessment for Great Sitkin Volcano, Alaska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Waythomas, Christopher F.; Miller, Thomas P.; Nye, Christopher J.</p> <p>2003-01-01</p> <p>Great Sitkin Volcano is a composite andesitic stratovolcano on Great Sitkin Island (51°05’ N latitude, 176°25’ W longitude), a small (14 x 16 km), circular volcanic island in the western Aleutian Islands of Alaska. Great Sitkin Island is located about 35 kilometers northeast of the community of Adak on Adak Island and 130 kilometers west of the community of Atka on Atka Island. Great Sitkin Volcano is an active volcano and has erupted at least eight times in the past 250 years (Miller and others, 1998). The most recent eruption in 1974 caused minor ash fall on the flanks of the volcano and resulted in the emplacement of a lava dome in the summit crater. The summit of the composite cone of Great Sitkin Volcano is 1,740 meters above sea level. The active crater is somewhat lower than the summit, and the highest point along its rim is about 1,460 meters above sea level. The crater is about 1,000 meters in diameter and is almost entirely filled by a lava dome emplaced in 1974. An area of active fumaroles, hot springs, and bubbling hot mud is present on the south flank of the volcano at the head of Big Fox Creek (see the map), and smaller ephemeral fumaroles and steam vents are present in the crater and around the crater rim. The flanking slopes of the volcano are gradual to steep and consist of variously weathered and vegetated blocky lava flows that formed during Pleistocene and Holocene eruptions. The modern edifice occupies a caldera structure that truncates an older sequence of lava flows and minor pyroclastic rocks on the east side of the volcano. The eastern sector of the volcano includes the remains of an ancestral volcano that was partially destroyed by a northwest-directed flank collapse. In winter, Great Sitkin Volcano is typically completely snow covered. Should explosive pyroclastic eruptions occur at this time, the snow would be a source of water for volcanic mudflows or lahars. In summer, much of the snowpack melts, leaving only a patchy distribution of snow on the volcano. Glacier ice is no longer present on the volcano or on other parts of Great Sitkin Island as previously reported by Simons and Mathewson (1955). Great Sitkin Island is presently uninhabited and is part of the Alaska Maritime National Wildlife Refuge, managed by the U.S. Fish and Wildlife Service.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70020433','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70020433"><span>The interplinian activity at Somma-Vesuvius in the last 3500 years</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Rolandi, G.; Petrosino, P.; Mc, Geehin J.</p> <p>1998-01-01</p> <p>Between 1884 B.C. and A.D. 472, eruptive activity at Somma-Vesuvius was dominated by the three plinian eruptions of Avellino (3550 yr B.P.), Pompei (A.D. 79) and A.D. 472 and, as a result, little attention has been given to the intervening interplinian activity. The interplinian events are here reconstructed using new data from twenty stratigraphic sections around the lower flanks of the volcano. Three main eruptions have been identified fro the protohistoric period (3550 yr B.P.-A.D. 79). The first two occurred shortly after the Avellino event and both show a progression from magmatic to phreatomagmatic behaviour. The third eruption (2700 B.P.) consisted of five phreatomagmetic episodes separated by the emplacement of mud flows. Only one event, the explosive erupton of A.D. 203, has been identified for the ancient historic period (A.D. 79-472). In contrast, the A.D. 472 eruption was followed during the medievel period (A.D. 472-1631) by comparatively vigorous interplinian activity, including four strombolian-phreatomagmatic events and extensive lava effusion, which formed a summit cone (destroyed in A.D. 1631) similar to that on Vesuvius today. Such regular alternations of plinian and interplinian events are evident only since 3550 yr B.P. and provide important constraints for forecasting future behaviour at Somma-Vesuvius.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.V33B3094N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.V33B3094N"><span>Geomorphological features of rootless cones in Myvatn, Iceland in comparison with Martian candidates</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Noguchi, R.; Kurita, K.</p> <p>2015-12-01</p> <p>Rootless cones (RC) have not been paid much attention so far because of their limited locations and their small size. They are formed by repeated phreatovolcanic explosions by lava-waterlogged sediments interactions. While the distribution is limited on the Earth, they have been pervasively recognized on Mars (e.g., Greeley and Fagents, 2001) and considered as a key marker in identifying lava flow. Although in-depth morphological comparisons are necessary, the terrestrial standard is not sufficient. Recent studies have clarified detailed characteristics of the distribution in the context of lava flow dynamics in Laki, Iceland (Hamilton et al., 2010a,b). However, we are still lacking of sufficient data of the morphology. To construct the terrestrial reference, we performed survey in Myvatn, Iceland.About 2300 years ago, lava flowed into old-Lake Myvatn, then formed RCs (Thorarinsson, 1953). There exists 3 morphological types; Single Cone (SC), a conical edifice with a summit crater, Double Cone (DC), composed of an inner cone with a summit crater within the summit crater of an outer cone, and multiple cone, similar to DC but with several inner cones. Through aerial photo survey, 1154 RCs (1056 are SC, 78 are DC and 20 are multiple one) are identified in this area. To know high-resolution topography of them, we apply kinematic GPS. Constituent materials of RCs are analyzed focusing on their bulk density, vesicularity, and grain size distribution.Geomorphological features of RCs are strongly correlated with its location and constituent materials. The crater diameter/bottom diameter ratio of cone, which is considered as an indicator of the explosivity, is larger around the lake and smaller far way from the lava source. This suggests an importance of available thermal energy as well as the water supply. The edifice morphology is grouped into 5 types; I: constant slopes that reach the repose angle; II: constant slopes lower than the repose angle; III: variable slopes with a step; IV: variable slopes that get steeper with higher altitude; and V: variable and small slope angles. We found these types correspond to their constituent materials and volumes. In this presentation, we show the relationship between RC morphology and other parameters, which can be useful as well as the planetary volcanology.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-GSFC_20171208_Archive_e001648.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-GSFC_20171208_Archive_e001648.html"><span>Ash Plume from Shiveluch</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-09</p> <p>When NASA’s Terra satellite passed over Russia’s Kamchatka Peninsula at noon local time (00:00 Universal Time) on October 6, 2012, Shilveluch Volcano was quiet. By the time NASA’s Aqua satellite passed over the area two hours later (bottom image), the volcano had erupted and sent a plume of ash over the Kamchatskiy Zaliv. The plume traveled about 90 kilometers (55 miles) toward the south-southeast, where a change in wind direction began pushing the plume toward the east. On October 6, 2012, the Kamchatka Volcanic Emergency Response Team (KVERT) reported that the ash plume from Shiveluch reached an altitude of 3 kilometers (9,800 feet) above sea level, and had traveled some 220 kilometers (140 miles) from the volcano summit. Shiveluch (also spelled Sheveluch) ranks among the biggest and most active volcanoes on the Kamchatka Peninsula. Rising to 3,283 meters (10,771 feet) above sea level, Shiveluch is a stratovolcano composed of alternating layers of hardened lava, compacted ash, and rocks ejected by previous eruptions. The beige-colored expanse of rock on the volcano’s southern slopes (visible in both images) is due to an explosive eruption that occurred in 1964. Part of Shiveluch’s southern flank collapsed, and the light-colored rock is avalanche debris left by that event. High-resolution imagery of Shiveluch shows very little vegetation within that avalanche zone. On October 6, 2012, KVERT cited observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on Terra and Aqua in detecting the Shiveluch eruption. This was not the first time that MODIS observed a Shiveluch eruption shortly after it started. In 2007, MODIS captured an image within minutes of the eruption’s start, before winds could blow the ash away from the summit. When NASA’s Terra satellite passed over Russia’s Kamchatka Peninsula at noon local time (00:00 Universal Time) on October 6, 2012, Shilveluch Volcano was quiet (top image). By the time NASA’s Aqua satellite passed over the area two hours later (bottom image), the volcano had erupted and sent a plume of ash over the Kamchatskiy Zaliv. The plume traveled about 90 kilometers (55 miles) toward the south-southeast, where a change in wind direction began pushing the plume toward the east. On October 6, 2012, the Kamchatka Volcanic Emergency Response Team (KVERT) reported that the ash plume from Shiveluch reached an altitude of 3 kilometers (9,800 feet) above sea level, and had traveled some 220 kilometers (140 miles) from the volcano summit. Shiveluch (also spelled Sheveluch) ranks among the biggest and most active volcanoes on the Kamchatka Peninsula. Rising to 3,283 meters (10,771 feet) above sea level, Shiveluch is a stratovolcano composed of alternating layers of hardened lava, compacted ash, and rocks ejected by previous eruptions. The beige-colored expanse of rock on the volcano’s southern slopes (visible in both images) is due to an explosive eruption that occurred in 1964. Part of Shiveluch’s southern flank collapsed, and the light-colored rock is avalanche debris left by that event. High-resolution imagery of Shiveluch shows very little vegetation within that avalanche zone. On October 6, 2012, KVERT cited observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on Terra and Aqua in detecting the Shiveluch eruption. This was not the first time that MODIS observed a Shiveluch eruption shortly after it started. In 2007, MODIS captured an image within minutes of the eruption’s start, before winds could blow the ash away from the summit. Credit: NASA Earth Observatory NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70012233','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70012233"><span>Geophysical observations of Kilauea volcano, Hawaii, 1. temporal gravity variations related to the 29 November, 1975, M = 7.2 earthquake and associated summit collapse</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Jachens, R.C.; Eaton, G.P.</p> <p>1980-01-01</p> <p>Repeated high-precision gravity measurements made near the summit of Kilauea volcano, Hawaii, have revealed systematic temporal variations in the gravity field associated with a major deflation of the volcano that followed the 29 November, 1975, earthquake and eruption. Changes in the gravity field with respect to a stable reference station on the south flank of neighboring Mauna Loa volcano were measured at 18 sites in the summit region of Kilauea and at 4 sites far removed from its summit. The original survey, conducted 10-23 November, 1975, was repeated during a two-week period after the earthquake. The results indicate that sometime between the first survey and the latter part of the second survey the gravity field at sites near the summit increased with respect to that at sites far removed from the summit. The pattern of gravity increase is essentially radially symmetrical, with a half-width slightly less than 3 km, about the point of maximum change 1.5 km southeast of Halemaumau pit crater. Gravity changes at sites near the summit correlate closely with elevation decreases that occurred sometime between leveling surveys conducted in late September 1975 and early January 1976. The systematic relation between gravity and elevation change (-1.71 ?? 0.05 (s.e.) ??gal/cm) shows that deflation was accompanied by a loss of mass from beneath the summit region. Mass balance calculations indicate that for all reasonable magma densities, the volume of magma withdrawn from beneath the summit region exceeded the volume of summit collapse. Analysis suggests that magma drained from at least two distinct areas south of Kilauea caldera that coincide roughly with two reservoir areas active during inflation before the 1967-1968 Kilauea eruption. ?? 1980.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70073903','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70073903"><span>Late Holocene Peléan-style eruption at Tacaná volcano, Mexico and Guatemala: past, present, and future hazards</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Macías, J. L.; Espíndola, J. M.; Garcia-Palomo, A.; Scott, K.M.; Hughes, S.; Mora, J C.</p> <p>2000-01-01</p> <p>Tacaná volcano, located on the border between Mexico and Guatemala, marks the northern extent of the Central American volcanic chain. Composed of three volcanic structures, it is a volcanic complex that has had periodic explosive eruptions for at least the past 40 k.y. The most recent major eruption occurred at the San Antonio volcano, the youngest volcanic edifice forming the complex, about 1950 yr ago. The Peléan style eruption, issued from the southwest part of the dome, and swept a 30° sector with a hot block and ash flow that traveled about 14 km along the Cahoacán ravine. Deposits from this event are well exposed around the town of Mixcun and were therefore given the name of that town, the Mixcun flow deposit. The Mixcun flow deposit is, in the channel facies, a light gray, massive, thick (>10 m), matrix-supported unit with dispersed lithic clasts of gravel to boulder size, divisible in some sections into a variable number of flow units. The overbank facies is represented by a thin (2 and has a minimum estimated volume of 0.12 km3. Basaltic-andesite inclusions (54% SiO2) and various signs of disequilibrium in the mineral assemblage of the two-pyroxene andesitic products (60%–63% SiO2) suggest that magma mixing may have triggered the eruption. Following deposition of the Mixcun flow deposit andesitic to dacitic (62%–64% SiO2) lava flows were extruded and a dacitic dome (64.4% SiO2) at the San Antonio summit formed. Syn-eruptive and posteruptive lahars flooded the main drainages of the Cahoacán and Izapa-Mixcun valleys in the area of the present city of Tapachula (population 250000) and the pre-Hispanic center of Izapa. Three radiocarbon ages date this event between A.D. 25 and 72 (range ±1σ, 38 B.C.–A.D. 216), which correlates with a halt in construction at Izapa (Hato phase of ca. 50 B.C.–A.D. 100), probably due to temporary abandonment of the city caused by lahars. Another similar event would produce extensive damage to the towns (population of about 68,000 people) now built upon the Mixcun flow deposit. The main summit of Tacaná volcano continues to show signs of fumarolic activity; the most recent period of activity in 1985–1986 culminated in a minor phreatic explosion.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA347024','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA347024"><span>Atlantis: An Open Architecture for Synergy of Process-Centered Environments and Computer-Supported Cooperative Work</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1998-04-01</p> <p>revision phase would be followed, after which a second review would be scheduled , and so forth, until the review succeeds. 2.3 Realization of the...normal rules, when Summit rules are inferred they are enqueued in a separate Summit queue and are scheduled for execution only after local forward... scheduling and activating activities according to the defined process; reac- tively triggering activities based on state changes; monitoring the process</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015E%26PSL.413...90P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015E%26PSL.413...90P"><span>Two magma bodies beneath the summit of Kīlauea Volcano unveiled by isotopically distinct melt deliveries from the mantle</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pietruszka, Aaron J.; Heaton, Daniel E.; Marske, Jared P.; Garcia, Michael O.</p> <p>2015-03-01</p> <p>The summit magma storage reservoir of Kīlauea Volcano is one of the most important components of the magmatic plumbing system of this frequently active basaltic shield-building volcano. Here we use new high-precision Pb isotopic analyses of Kīlauea summit lavas-from 1959 to the active Halema'uma'u lava lake-to infer the number, size, and interconnectedness of magma bodies within the volcano's summit reservoir. From 1971 to 1982, the 206Pb/204Pb ratios of the lavas define two separate magma mixing trends that correlate with differences in vent location and/or pre-eruptive magma temperature. These relationships, which contrast with a single magma mixing trend for lavas from 1959 to 1968, indicate that Kīlauea summit eruptions since at least 1971 were supplied from two distinct magma bodies. The locations of these magma bodies are inferred to coincide with two major deformation centers identified by geodetic monitoring of the volcano's summit region: (1) the main locus of the summit reservoir ∼2-4 km below the southern rim of Kīlauea Caldera and (2) a shallower magma body <2 km below the eastern rim of Halema'uma'u pit crater. Residence time modeling suggests that the total volume of magma within Kīlauea's summit reservoir during the late 20th century (1959-1982) was exceedingly small (∼0.1-0.5 km3). Voluminous Kīlauea eruptions, such as the ongoing, 32-yr old Pu'u 'Ō'ō rift eruption (>4 km3 of lava erupted), must therefore be sustained by a nearly continuous supply of new melt from the mantle. The model results show that a minimum of four compositionally distinct, mantle-derived magma batches were delivered to the volcano (at least three directly to the summit reservoir) since 1959. These melt inputs correlate with the initiation of energetic (1959 Kīlauea Iki) and/or sustained (1969-1974 Mauna Ulu, 1983-present Pu'u 'Ō'ō and 2008-present Halema'uma'u) eruptions. Thus, Kīlauea's eruptive behavior is partly tied to the delivery of new magma batches from the volcano's source region within the Hawaiian mantle plume.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70170792','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70170792"><span>Eruption style at Kīlauea Volcano in Hawai‘i linked to primary melt composition</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Sides. I.R.,; Edmonds, M.; Maclennan, J.; Swanson, Don; Houghton, Bruce F.</p> <p>2014-01-01</p> <p>Explosive eruptions at basaltic volcanoes have been linked to gas segregation from magmas at shallow depths in the crust. The composition of primary melts formed at greater depths was thought to have little influence on eruptive style. Ocean island basaltic volcanoes are the product of melting of a geochemically heterogeneous mantle plume and are expected to give rise to heterogeneous primary melts. This range in primary melt composition, particularly with respect to the volatile components, will profoundly influence magma buoyancy, storage and eruption style. Here we analyse the geochemistry of a suite of melt inclusions from 25 historical eruptions at the ocean island volcano of Kīlauea, Hawai‘i, over the past 600 years. We find that more explosive styles of eruption at Kīlauea Volcano are associated statistically with more geochemically enriched primary melts that have higher volatile concentrations. These enriched melts ascend faster and retain their primary nature, undergoing little interaction with the magma reservoir at the volcano’s summit. We conclude that the eruption style and magma-supply rate at Kīlauea are fundamentally linked to the geochemistry of the primary melts formed deep below the volcano. Magmas might therefore be predisposed towards explosivity right at the point of formation in their mantle source region.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70186951','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70186951"><span>Evidence for large compositional ranges in coeval melts erupted from Kīlauea's summit reservoir: Chapter 7</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Helz, Rosalind T.; Clague, David A.; Mastin, Larry G.; Rose, Timothy R.; Carey, Rebecca; Cayol, Valérie; Poland, Michael P.; Weis, Dominique</p> <p>2015-01-01</p> <p>Petrologic observations on Kīlauea's lavas include abundant microprobe analyses of glasses, which show the range of melts available in Kīlauea's summit reservoir over time. During the past two centuries, compositions of melts erupted within the caldera have been limited to MgO = 6.3–7.5 wt%. Extracaldera lavas of the 1959, 1971, and 1974 eruptions contain melts with up to 10.2, 8.9, and 9.2 wt% MgO, respectively, and the 1924 tephra contains juvenile Pele's tears with up to 9.1 wt% MgO. Melt compositions from explosive deposits at Kīlauea, including the Keanakāko‘i (A.D. 1500–1800), Kulanaokuaiki (A.D. 400–1000), and Pāhala (10–25 ka) tephra units, show large ranges of MgO contents. The range of melt MgO is 6.5–11.0 wt% for the Keanakāko‘i; the Kulanaokuaiki extends to 12.5% MgO and the Pāhala Ash includes rare shards with 13–14.5% MgO. The frequency distributions for MgO in the Keanakāko‘i and Kulanaokuaiki glasses are bimodal, suggesting preferential magma storage at two different depths. Kīlauea's summit reservoir contains melts ranging from 6.5 to at least 11.0 wt% MgO, and such melts were available for sampling near instantaneously and repeatedly over centuries. More magnesian melts are inferred to have risen directly from greater depth.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMED41C..08K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMED41C..08K"><span>Youth Climate Summits: Empowering & Engaging Youth to Lead on Climate Change</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kretser, J.</p> <p>2017-12-01</p> <p>The Wild Center's Youth Climate Summits is a program that engages youth in climate literacy from knowledge and understanding to developing action in their schools and communities. Each Youth Climate Summit is a one to three day event that brings students and teachers together to learn about climate change science, impacts and solutions at a global and local level. Through speakers, workshops and activities, the Summit culminates in a student-driven Climate Action Plan that can be brought back to schools and communities. The summits have been found to be powerful vehicles for inspiration, learning, community engagement and youth leadership development. Climate literacy with a focus on local climate impacts and solutions is a key component of the Youth Climate Summit. The project-based learning surrounding the creation of a unique, student driven, sustainability and Climate Action Plan promotes leadership skills applicable and the tools necessary for a 21st Century workforce. Student driven projects range from school gardens and school energy audits to working with NYS officials to commit to going 100% renewable electricty at the three state-owned downhill ski facilities. The summit model has been scaled and replicated in other communities in New York State, Vermont, Ohio, Michigan and Washington states as well as internationally in Finland, Germany and Sri Lanka.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1811506W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1811506W"><span>Volcanic gas emissions during active dome growth at Mount Cleveland, Alaska, August 2015</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Werner, Cynthia; Kern, Christoph; Lyons, John; Kelly, Peter; Schneider, David; Wallace, Kristi; Wessels, Rick</p> <p>2016-04-01</p> <p>Volcanic gas emissions and chemistry data were measured for the first time at Mount Cleveland (1730 m) in the Central Aleutian arc, Alaska, on August 14-15, 2015 as part of the NSF-GeoPRISMS initiative, and co-funded by the Deep Carbon Observatory (DCO) and the USGS Alaska Volcano Observatory. The measurements were made in the month following two explosive events (July 21 and August 7, 2015) that destroyed a small dome (˜50x85 m), which had experienced episodic growth in the crater since November, 2014. These explosions resulted in the elevation of the aviation color code and alert level from Yellow/Advisory to Orange/Watch on July 21, 2015. Between the November, 2014 and July, 2015 dome-destroying explosions, the volcano experienced: (1) frequent periods of elevated surface temperatures in the summit region (based on Mid-IR satellite observations), (2) limited volcano-seismic tremor, (3) visible degassing as recorded in webcam images with occasionally robust plumes, and (4) at least one aseismic volcanic event that deposited small amounts of ash on the upper flanks of the volcano (detected by infrasound, observed visually and in Landsat 8 images). Intermittent plumes were also sometimes detectable up to 60 km downwind in Mid-IR satellite images, but this was not typical. Lava extrusion resumed following the explosion as indicated in satellite data by highly elevated Mid-IR surface temperatures, but was not identifiable in seismic data. By early-mid August, 2015, a new dome growing in the summit crater had reached 80 m across with temperatures of 550-600 C as measured on August 4 with a helicopter-borne thermal IR camera. A semitransparent plume extended several kilometers downwind of the volcano during the field campaign. A helicopter instrumented with an upward-looking UV spectrometer (mini DOAS) and a Multi-GAS was used to measure SO2 emission rates and in situ mixing ratios of H2O, CO2, SO2, and H2S in the plume. On August 14 and 15, 2015, a total of 14 helicopter traverses made beneath the plume resulted in SO2 emission rates ranging from 460 to 860 t/d. Four of the 14 measurements were made during a dedicated gas flight where emission rates varied between 480-580 t/d SO2 over an approximate 20 minute period on August 15, demonstrating the short-term variability of emissions. Transects through the plume were also flown during the gas flight with the highest concentrations (˜ 0.5 ppm SO2) measured approximately 2.6 km downwind of the volcano. Volcanic CO2 was at detection limits and in-plume concentrations exceeded background air by only 1- 1.5 ppm. Volcanic H2O could not be resolved above atmospheric background and H2S was not detected. Low molar C/S ratios derived from these data (< 3) are consistent with the presence of shallow magma in the system and the observed growth of a new lava dome. Gas emissions data will be compared with the low level background seismicity and infrasound from the Cleveland geophysical network.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JVGR..196..111F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JVGR..196..111F"><span>Adventive hydrothermal circulation on Stromboli volcano (Aeolian Islands, Italy) revealed by geophysical and geochemical approaches: Implications for general fluid flow models on volcanoes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Finizola, A.; Ricci, T.; Deiana, R.; Cabusson, S. Barde; Rossi, M.; Praticelli, N.; Giocoli, A.; Romano, G.; Delcher, E.; Suski, B.; Revil, A.; Menny, P.; Di Gangi, F.; Letort, J.; Peltier, A.; Villasante-Marcos, V.; Douillet, G.; Avard, G.; Lelli, M.</p> <p>2010-09-01</p> <p>On March 15th 2007 a paroxysmal explosion occurred at the Stromboli volcano. This event generated a large amount of products, mostly lithic blocks, some of which impacted the ground as far as down to 200 m a.s.l., about 1.5 km far away from the active vents. Two days after the explosion, a new vapour emission was discovered on the north-eastern flank of the volcanic edifice, at 560 m a.s.l., just above the area called "Nel Cannestrà". This new vapour emission was due to a block impact. In order to investigate the block impact area to understand the appearance of the vapour emission, we conducted on May 2008 a multidisciplinary study involving Electrical Resistivity Tomography (ERT), Ground Penetrating Radar (GPR), Self-Potential (SP), CO 2 soil diffuse degassing and soil temperature surveys. This complementary data set revealed the presence of an anomalous conductive body, probably related to a shallow hydrothermal level, at about 10-15 m depth, more or less parallel to the topography. It is the first time that such a hydrothermal fluid flow, with a temperature close to the water boiling point (76 °C) has been evidenced at Stromboli at this low elevation on the flank of the edifice. The ERT results suggest a possible link between (1) the main central hydrothermal system of Stromboli, located just above the plumbing system feeding the active vents, with a maximum of subsurface soil temperature close to 90 °C and limited by the NeoStromboli summit crater boundary and (2) the investigated area of Nel Cannestrà, at ~ 500 m a.s.l., a buried eruptive fissure active 9 ka ago. In parallel, SP and CO 2 soil diffuse degassing measurements suggest in this sector at slightly lower elevation from the block impact crater a magmatic and hydrothermal fluid rising system along the N41° regional fault. A complementary ERT profile, on May 2009, carried out from the NeoStromboli crater boundary down to the block impact crater displayed a flank fluid flow apparently connected to a deeper system. The concept of shallow hydrothermal level have been compared to similar ERT results recently obtained on Mount Etna and La Fossa cone of Vulcano. This information needs to be taken into account in general fluid flow models on volcanoes. In particular, peripheral thermal waters (as those bordering the north-eastern coast of Stromboli) could be contaminated by hydrothermal and magmatic fluids coming from regional faults but also from the summit.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.epa.gov/remedytech/optimization-review-french-gulchwellington-oro-mine-site-water-treatment-plant','PESTICIDES'); return false;" href="https://www.epa.gov/remedytech/optimization-review-french-gulchwellington-oro-mine-site-water-treatment-plant"><span>Optimization Review: French Gulch/Wellington-Oro Mine Site Water Treatment Plant, Breckenridge, Summit County, Colorado</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.epa.gov/pesticides/search.htm">EPA Pesticide Factsheets</a></p> <p></p> <p></p> <p>The French Gulch/Wellington-Oro Mine Site is located near the town of Breckenridge in Summit County, Colorado. Environmental contamination of surface water, groundwater, soil and sediment at the site resulted from mining activities dating to the 1880s.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFM.V41A0972C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFM.V41A0972C"><span>Analysis of Vulnerability Around The Colima Volcano, MEXICO</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carlos, S. P.</p> <p>2001-12-01</p> <p>The Colima volcano located in the western of the Trasmexican Volcanic Belt, in the central portion of the Colima Rift Zone, between the Mexican States of Jalisco and Colima. The volcano since January of 1998 presents a new activity, which has been characterized by two stages: the first one was an effusive phase that begin on 20 November 1998 and finish by the middle of January 1999. On February 10of 1999 a great explosion in the summit marked the beginning of an explosive phase, these facts implies that the eruptive process changes from an effusive model to an explosive one. Suárez-Plascencia et al, 2000, present hazard maps to ballistic projectiles, ashfalls and lahars for this scenario. This work presents the evaluation of the vulnerability in the areas identified as hazardous in the maps for ballistic, ashfalls and lahars, based on the economic elements located in the middle and lower sections of the volcano building, like agriculture, forestry, agroindustries and communication lines (highways, power, telephonic, railroad, etc). The method is based in Geographic Information Systems, using digital cartography scale 1:50,000, digital orthophotos from the Instituto Nacional de Estadística, Geografía e Informática, SPOT and Landsat satellite images from 1997 and 2000 in the bands 1, 2 and 3. The land use maps obtained for 1997 and 2000, were compared with the land use map reported by Suárez in 1992, from these maps an increase of the 5 porcent of the sugar cane area and corn cultivations were observed compared of those of 1990 (1225.7 km2) and a decrease of the forest surface, moving the agricultural limits uphill, and showing also some agave cultivation in the northwest and north hillslopes of the Nevado de Colima. This increment of the agricultural surface results in bigger economic activity in the area, which makes that the vulnerability also be increased to different volcanic products emitted during this phase of activity. The degradation of the soil by the agriculture and forestry, mainly in the east hillslope of the volcano is another factor that generate remoulded material that in the event of an extraordinary rainsfall during an explosive events, could increase the size of the lahar or generate flows of mud that may affect the towns, villages (like Atenquique, which has been affected in 1957 by a large lahar), and could generate strong damages to the communication lines affecting distant places as Guadalajara city and the Port of Manzanillo.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.V52B..01P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.V52B..01P"><span>The Consequences of Increased Magma Supply to Kilauea Volcano, Hawai`i</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Poland, M.; Miklius, A.; Sutton, A. J.; Orr, T.</p> <p>2007-12-01</p> <p>The summer of 2007 was a time of intense activity at Kilauea. By mid-2007, ~4 years of summit inflation had uplifted and extended the caldera by 30 cm and 55 cm, respectively. Lava continued to erupt from the Pu`u `O`o vent on the east rift zone (ERZ) during the inflation. On May 24, 2007, two M4+ normal-faulting earthquakes occurred on caldera-bounding faults southeast of the summit. The seismicity did not affect summit inflation, which continued until June 17 when a dike intruded the upper and middle ERZ, causing a pause in the eruption, collapse of Pu`u `O`o's floor, and a small eruption 6 km uprift of Pu`u `O`o. The inflated state of the summit, relative timing of summit deflation and east rift zone extension, and abundant co-intrusive earthquake activity suggest forcible intrusion of magma. Lava returned to Pu`u `O`o by July 2, forming a lake that gradually refilled much of the collapsed crater. Early on July 21, the lake drained suddenly, the cone began to collapse, and a 2-km-long series of discontinuous eruptive fissures opened on and beyond the east flank of Pu`u `O`o. Sesimicity in Kilauea's south flank has been elevated since June and several M3+ earthquakes have occurred there, including a M5.4 on August 13. An increase in magma supply to Kilauea's shallow magmatic system is the probable cause for the events of summer 2007. Summit inflation since 2003 occurred during a period of constant or increasing magma supply to Pu`u `O`o, based on SO2 emissions from the ERZ. The rate of inflation increased markedly in early 2006, and uplift also began in the southwest rift zone. CO2 emissions at the summit, indicative of the quantity of magma degassing beneath Kilauea's caldera, more than doubled between 2003 and 2006. Also since 2003, the ERZ immediately downrift of Pu`u `O`o extended, and subsidence in the lower ERZ ceased. Together, these factors suggest that the magma supply rate to Kilauea's shallow magmatic system (the summit and rift zones above about 5 km depth) approximately doubled between 2003 and 2006. Subsequent volcanic and earthquake activity, including the events of mid-2007, are probably a result (either directly or indirectly) of this increase.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.V33E..08T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.V33E..08T"><span>Dueling Volcanoes: How Activity Levels At Kilauea Influence Eruptions At Mauna Loa</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Trusdell, F.</p> <p>2011-12-01</p> <p>The eruption of Kilauea at Pu`u `O`o is approaching its 29th anniversary. During this time, Mauna Loa has slowly inflated following its most recent eruption in 1984. This is Mauna Loa's longest inter-eruptive interval observed in HVO's 100 years of operation. When will the next eruption of Mauna Loa take place? Is the next eruption of Mauna Loa tied to the current activity at Kilauea? Historically, eruptive periods at Kilauea and Mauna Loa volcanoes appear to be inversely correlated. In the past, when Mauna Loa was exceptionally active, Kilauea Volcano was in repose, recovery, or in sustained lava lake activity. Swanson and co-workers (this meeting) have noted that explosive activity on Kilauea, albeit sporadic, was interspersed between episodes of effusive activity. Specifically, Swanson and co-workers note as explosive the time periods between 300 B.C.E.-1000 C.E and 1500-1800 C.E. They also point to evidence for low magma supply to Kilauea during these periods and few flank eruptions. During the former explosive period, Mauna Loa was exceedingly active, covering approximately 37% of its surface or 1882 km2, an area larger than Kilauea. This period is also marked by summit activity at Mauna Loa sustained for 300 years. In the 1500-1800 C.E. period, Mauna Loa was conspicuously active with 29 eruptions covering an area of 446 km2. In the late 19th and early 20th century, Kilauea was dominated by nearly continuous lava-lake activity. Meanwhile Mauna Loa was frequently active from 1843 C.E. to 1919 C.E., with 24 eruptions for an average repose time of 3.5 years. I propose that eruptive activity at one volcano may affect eruptions at the other, due to factors that impact magma supply, volcanic plumbing, and flank motion. This hypothesis is predicated on the notion that when the rift zones of Kilauea, and in turn its mobile south flank, are active, Mauna Loa's tendency to erupt is diminished. Kilauea's rift zones help drive the south flank seaward, in turn, as Mauna Loa inflates its flank is not buttressed on the southeast. Consequently, asymmetrical spreading occurs resulting in dilation of the shallow magma storage centers, which ultimately culminates in decreased magma pressure and therefore lessened ability to erupt. Whether or not this hypothesis is accurate, there is growing geologic evidence for inverse activity levels at both volcanoes. This hypothesis is readily testable and can have profound implications on how we monitor shield volcanoes, which impacts our ability to forecast eruptions, conduct hazard assessments, and risk analysis.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA22153.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA22153.html"><span>Investigating Mars: Arsia Mons</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2017-12-28</p> <p>This VIS image shows part of the northwestern margin of the summit caldera. Along with the faults caused by the collapse of the summit materials into the void of the emptied magma chamber, there are many small lobate lava flows and collapse features. The scalloped depressions are most likely created by collapse of the roof of lava tubes. Lava tubes originate during eruption event, when the margins of a flow harden around a still flowing lava stream. When an eruption ends these can become hollow tubes within the flow. With time, the roof of the tube may collapse into the empty space below. The tubes are linear, so the collapse of the roof creates a linear depression. This image illustrates the many processes that occurred in the formation of the volcano. Arsia Mons is the southernmost of the Tharsis volcanoes. It is 270 miles (450km) in diameter, almost 12 miles (20km) high, and the summit caldera is 72 miles (120km) wide. For comparison, the largest volcano on Earth is Mauna Loa. From its base on the sea floor, Mauna Loa measures only 6.3 miles high and 75 miles in diameter. A large volcanic crater known as a caldera is located at the summit of all of the Tharsis volcanoes. These calderas are produced by massive volcanic explosions and collapse. The Arsia Mons summit caldera is larger than many volcanoes on Earth. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 17117 Latitude: -8.43321 Longitude: 239.488 Instrument: VIS Captured: 2005-10-23 16:52 https://photojournal.jpl.nasa.gov/catalog/PIA22153</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.9216D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.9216D"><span>Moment tensor inversion of tremor events at Arenal Volcano (Costa Rica)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Davi, Rosalia; O'Brien, Gareth; Lokmer, Ivan; Bean, Christopher; Lesage, Philippe; de Barros, Louis</p> <p>2010-05-01</p> <p>Arenal is a small, andesitic stratovolcano located in north-western Costa Rica, 97 km from the capital San Josè. Arenal's explosive activity is preceded, and accompanied, by different types of seismic events such as long period events, explosions, tremor and sporadic tectonic swarms. Tremor is the most common type of event recorded at Arenal with durations of up to several hours. Both spasmodic (1-6 Hz) and harmonic (0.9-2 Hz) tremor are observed with no clear difference in the genesis of each; the former can progressively evolve into the latter and vice-versa. However, the origin of the tremor is, at present, not fully understood. In order to retrieve the source mechanism generating these types of events, a moment tensor inversion is performed. A dataset recorded on the volcano, during a seismic experiment carried out in 2005, is used for the inversion. This dataset consists of ten days of data, from which two main groups of tremor at different frequencies (group one at 0.8-1.5 Hz and group two at 1.8-2.5 Hz) have been selected. A major difficulty in any inversion of tremor is that a clear onset can rarely be determined and hence retrieving the direct arrivals from the source is impossible. Usually, these arrivals are heavily contaminated by scattered waves. On Arenal the initial part of the tremor bands can be isolated, therefore offering a good opportunity to invert tremor for the source mechanism. The Green's functions used in the inversion were calculated using 3D numerical simulations including the real topography of the volcano and the best estimation of the velocity model available for Arenal. This velocity model was retrieved from seismic refraction experiments and sounding using the SPAC method. For each day, different tremor starting bands have been selected and divided into the groups mentioned above. For each band a source location is determined by performing a grid search through a volume of 4735 possible source points located under the crater summit. From the evaluation of the misfit values, a common source location is determined. The source appears to be located in shallow position, (less than 200 meters deep) under the crater summit. The source mechanisms for each tremor bands are retrieved for each day using the inversion procedure.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017E%26PSL.475..231B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017E%26PSL.475..231B"><span>A new approach to investigate an eruptive paroxysmal sequence using camera and strainmeter networks: Lessons from the 3-5 December 2015 activity at Etna volcano</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bonaccorso, A.; Calvari, S.</p> <p>2017-10-01</p> <p>Explosive sequences are quite common at basaltic and andesitic volcanoes worldwide. Studies aimed at short-term forecasting are usually based on seismic and ground deformation measurements, which can be used to constrain the source region and quantify the magma volume involved in the eruptive process. However, during single episodes of explosive sequences, integration of camera remote sensing and geophysical data are scant in literature, and the total volume of pyroclastic products is not determined. In this study, we calculate eruption parameters for four powerful lava fountains occurring at the main and oldest Mt. Etna summit crater, Voragine, between 3 and 5 December 2015. These episodes produced impressive eruptive columns and plume clouds, causing lapilli and ash fallout to more than 100 km away. We analyse these paroxysmal events by integrating the images recorded by a network of monitoring cameras and the signals from three high-precision borehole strainmeters. From the camera images we calculated the total erupted volume of fluids (gas plus pyroclastics), inferring amounts from 1.9 ×109 m3 (first event) to 0.86 ×109 m3 (third event). Strain changes recorded during the first and most powerful event were used to constrain the depth of the source. The ratios of strain changes recorded at two stations during the four lava fountains were used to constrain the pyroclastic fraction for each eruptive event. The results revealed that the explosive sequence was characterized by a decreasing trend of erupted pyroclastics with time, going from 41% (first event) to 13% (fourth event) of the total erupted pyroclastic volume. Moreover, the volume ratio fluid/pyroclastic decreased markedly in the fourth and last event. To the best of our knowledge, this is the first time ever that erupted volumes of both fluid and pyroclastics have been estimated for an explosive sequence from a monitoring system using permanent cameras and high precision strainmeters. During future explosive paroxysmal sequences this new approach might help in monitoring their evolution also to understand when/if they are going to finish. Knowledge of the total gas and pyroclastic fractions erupted during each lava fountain episode would improve our understanding of their processes and eruptive behaviour.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.8715L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.8715L"><span>The 2007 and 2014 eruptions of Stromboli at match: monitoring the potential occurrence of effusion-driven basaltic paroxysmal explosions from a volcanic CO2 flux perspective</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liuzzo, Marco; Aiuppa, Alessandro; Salerno, Giuseppe; Burton, Mike; Federico, Cinzia; Caltabiano, Tommaso; Giudice, Gaetano; Giuffrida, Giovanni</p> <p>2015-04-01</p> <p>The recent effusive unrests of Stromboli occurred in 2002 and 2007 were both punctuated by short-lived, violent paroxysmal explosions generated from the volcano's summit craters. When effusive activity recently resumed on Stromboli, on 6 August 2014, much concern was raised therefore on whether or not a paroxysm would have occurred again. The occurrence of these potentially hazardous events has stimulated research toward understanding the mechanisms through which effusive eruptions can perturb the volcano's plumbing system, to eventually trigger a paroxysm. The anomalously large CO2 gas emissions measured prior to the 15 March 2007 paroxysmal explosion of Stromboli [1] have first demonstrated the chance to predict days in advance the effusive-to-explosive transition. Here 2007 and 2014 volcanic CO2 flux records have been compared for exploring causes/conditions that had not triggered any paroxysm event in the 2014 case. We show that the 2007 and 2014 datasets shared both similarities and remarkable differences. The pre-eruptive trends of CO2 and SO2 flux emissions were strikingly similar in both 2007 and 2014, indicating similar conditions within the plumbing system prior to onset of both effusive crises. In both events, the CO2 flux substantially accelerated (relative to the pre-eruptive mean flux) after onset of the effusion. However, this CO2 flux acceleration was a factor 3 lower in 2014 than in 2007, and the excess CO2 flux (the fraction of CO2 not associated with the shallowly emplaced/erupted magma, and therefore contributed by the deep magmatic system) never returned to the very high levels observed prior to the 15 March 2007 paroxysm. We conclude therefore that, although similar quantities of magma were effusively erupted in 2007 and 2014, the deep magmatic system was far less perturbed in the most recent case. We speculate that the rate at which the deep magmatic system is decompressed, rather than the level of de-compression itself, determine if the deep Stromboli's plumbing system is prone to erupt in a paroxysm, or not. [1] A. Aiuppa et al., Geophys Res Lett, 2010.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1991E%26PSL.107..318C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1991E%26PSL.107..318C"><span>Gas-rich submarine exhalations during the 1989 eruption of Macdonald Seamount</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>C´e, J.-L.; Stoffers, P.; McMurtry, G.; Richnow, H.; Puteanus, D.; Sedwick, P.</p> <p>1991-11-01</p> <p>In January 1989 we observed submarine eruptions on the summit of Macdonald volcano during a French-German diving programme with the IFREMER submersible Cyana. Gas-streaming of large amounts of CH 4, CO 2 and SO 2 from summit vents, inferred from water column anomalies and observed by submersible, was accompanied on the sea surface by steam bursts, turbulence, red-glowing gases, and black bubbles comprising volcanic ash, sulphur and sulphides. Chloride depletion of water sampled on the floor of an actively degassing summit crater suggests either boiling and phase separation or additions of magmatic water vapour. Submersible observations, in-situ sampling and shipboard geophysical and hydrographic measurements show that the hydrothermal system of this hotspot volcano is distinguished by the influence of magmatic gases released from its shallow summit.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=10524&hterms=active+volcanoes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dactive%2Bvolcanoes','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=10524&hterms=active+volcanoes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dactive%2Bvolcanoes"><span>Eruption of Shiveluch Volcano, Kamchatka Peninsula</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2007-01-01</p> <p>On March 29, 2007, the Shiveluch Volcano on the Russian Federation's Kamchatka Peninsula erupted. According to the Alaska Volcano Observatory the volcano underwent an explosive eruption between 01:50 and 2:30 UTC, sending an ash cloud skyward roughly 9,750 meters (32,000 feet), based on visual estimates. The Moderate Resolution Imaging Spectroradiometer (MODIS) flying onboard NASA's Aqua satellite took this picture at 02:00 UTC on March 29. The top image shows the volcano and its surroundings. The bottom image shows a close-up view of the volcano at 250 meters per pixel. Satellites often capture images of volcanic ash plumes, but usually as the plumes are blowing away. Plumes have been observed blowing away from Shiveluch before. This image, however, is different. At the time the Aqua satellite passed overhead, the eruption was recent enough (and the air was apparently still enough) that the ash cloud still hovered above the summit. In this image, the bulbous cloud casts its shadow northward over the icy landscape. Volcanic ash eruptions inject particles into Earth's atmosphere. Substantial eruptions of light-reflecting particles can reduce temperatures and even affect atmospheric circulation. Large eruptions impact climate patterns for years. A massive eruption of the Tambora Volcano in Indonesia in 1815, for instance, earned 1816 the nickname 'the year without a summer.' Shiveluch is a stratovolcano--a steep-sloped volcano composed of alternating layers of solidified ash, hardened lava, and volcanic rocks. One of Kamchatka's largest volcanoes, it sports a summit reaching 3,283 meters (10,771 feet). Shiveluch is also one of the peninsula's most active volcanoes, with an estimated 60 substantial eruptions in the past 10,000 years.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70014405','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70014405"><span>Active high-resolution seismic tomography of compressional wave velocity and attenuation structure at Medicine Lake Volcano, northern California Cascade Range</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Evans, J.R.; Zucca, J.J.</p> <p>1988-01-01</p> <p>Medicine Lake volcano is a basalt through rhyolite shield volcano of the Cascade Range, lying east of the range axis. The Pg wave from eight explosive sources which has traveled upward through the target volume to a dense array of 140 seismographs provides 1- to 2-km resolution in the upper 5 to 7 km of the crust beneath the volcano. The experiment tests the hypothesis that Cascade Range volcanoes of this type are underlain only by small silicic magma chambers. We image a low-velocity low-Q region not larger than a few tens of cubic kilometers in volume beneath the summit caldera, supporting the hypothesis. A shallower high-velocity high-density feature, previously known to be present, is imaged for the first time in full plan view; it is east-west elongate, paralleling a topographic lineament between Medicine Lake volcano and Mount Shasta. Differences between this high-velocity feature and the equivalent feature at Newberry volcano, a volcano in central regon resembling Medicine Lake volcano, may partly explain the scarcity of surface hydrothermal features at Medicine Lake volcano. A major low-velocity low-Q feature beneath the southeast flank of the volcano, in an area with no Holocene vents, is interpreted as tephra, flows, and sediments from the volcano deeply ponded on the downthrown side of the Gillem fault. A high-Q normal-velocity feature beneath the north rim of the summit caldera may be a small, possibly hot, subsolidus intrusion. A high-velocity low-Q region beneath the eastern caldera may be an area of boiling water between the magma chamber and the ponded east flank material. -from Authors</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss023e027737.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss023e027737.html"><span>Earth Observations taken by the Expedition 23 Crew</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2010-04-23</p> <p>ISS023-E-027737 (23 April 2010) --- Nevado del Ruiz volcano in Colombia is featured in this image photographed by an Expedition 23 crew member on the International Space Station. The large Nevado del Ruiz volcano (center) is located approximately 140 kilometers to the northwest of the capital city of Bogota and covers an area of over 200 square kilometers. Nevado del Ruiz is a stratovolcano – a type of volcano built from successive layers of lava, ash, and pyroclastic flow deposits – formed by magma generated above the boundary between the subducting Nazca and overriding South American tectonic plates. The historical record of eruptions extends back to 1570, but the most damaging eruption in recent times took place in 1985. On Nov. 13, 1985, an explosive eruption at the Arenas Crater (center) melted ice and snow at the summit of the volcano. This lead to the formation of mudflows (or lahars) that swept tens of kilometers down river valleys along the volcano’s flanks, resulting in the deaths of at least 23,000 people. Most of the fatalities occurred in the town of Armero which was completely inundated by lahars. Eruptive activity at Nevado del Ruiz may have occurred in 1994, but this is not confirmed. The volcano’s summit and upper flanks are covered by several glaciers that appear as a white mass surrounding the one-kilometer-wide Arenas Crater; meltwater from these glaciers has incised the gray to tan ash and pyroclastic flow deposits mantling the lower slopes. A well-defined lava flow is visible at lower right. This photograph was taken at approximately 7:45 a.m. local time when the sun was still fairly low above the horizon, leading to shadowing to the west of topographic high points.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFM.V31A0950G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFM.V31A0950G"><span>Diffuse Emission of Carbon Dioxide From Irazú Volcano, Costa Rica, Central America</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Galindo, I.; Melian, G.; Ramirez, C.; Salazar, J.; Hernandez, P.; Perez, N.; Fernandez, M.; Notsu, K.</p> <p>2001-12-01</p> <p>Irazú (3,432 m) is a stratovolcano situated 50 Km east of San José, the capital of Costa Rica. Major geomorphological features at Irazú are five craters (Main Crater, Diego de La Haya, Playa Hermosa, La Laguna and El Piroclástico), and at least 10 satellitic cones which are located on its southern flank. Its eruptive history is known from 1723. Since then, have ocurred at least 23 eruptions. All known Holocene eruptions have been explosive. The focus of eruptions at the summit crater complex has migrated to the west towards the historically active crater from 1963 to 1965. Diffuse degassing studies are becoming an additional geochemical tool for volcanic surveillance. The purpose of this study is to evaluate the spatial distribution of diffuse CO2 emission as well as CO2 efflux from Irazú volcano. A soil CO2 flux survey of 201 sampling sites was carried out at the summit of Irazú volcano in March 2001. Sampling site distribution covered an area of 3.5 Km2. Soil CO2 efflux measurements were performed by means of a portable NDIR sensor LICOR-800. Soil CO2 efflux values ranged from non-detectable values to 316.1 gm-2d-1 Statistical-graphical analysis of the data showed three overlapping geochemical populations. The background mean is 3 gm-2d-1 and represents 91.3 % of the total data. Peak group showed a mean of 18 gm-2d-1 and represented 1.2 % of the data. Anomalous CO2 flux values are mainly detected in the South sector of the main crater, where landslides have previously occurred. Diffuse CO2 degassing rate of the study area yields 44.2 td-1.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018EP%26S...70...67C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018EP%26S...70...67C"><span>The thermal signature of Aso Volcano during unrest episodes detected from space and ground-based measurements</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cigolini, Corrado; Coppola, Diego; Yokoo, Akihiko; Laiolo, Marco</p> <p>2018-04-01</p> <p>The thermal signature of Aso Volcano (Nakadake) during unrest episodes has been analyzed by combining the MODIS-MIROVA data set (2000-2017) with high-resolution images (LANDSAT 8 OLI and Sentinel 2) and ground-based thermal observations (2013-2017). The site of major activity (crater 1) is located at the summit of the volcano and is composed by a fumarole field (located in the South Area) and an acidic lake (replaced by a Central Pit during Strombolian phases). The volcanic radiative power (VRP) obtained by nighttime satellite data during the reference period was mainly below 3 MW. This thermal threshold marks the transition from high fumarole activity (HFA) to Strombolian eruptions (SE). However, periods characterized by sporadic phreatic eruptions (PE, eventually bearing phreatomagmatic episodes), which is the prevalent phase during unrest episodes, exhibit very low VRP values, being around 0.5 MW, or below. The statistical analysis of satellite data shows that the transition from HFA to Strombolian activity (which started on August 2014 and ceased in May 2015) occurs when VRP values are above the cited 3 MW threshold. In particular during marked Strombolian phases (November-December 2014), the radiative power was higher than 4 MW, reaching peak values up to 15.6 MW (on December 7, 2014, i.e., 10 days after the major Strombolian explosion of November 27). Conversely, ground-based measurements show that heat fluxes recorded by FLIR T440 Thermo-camera on the fumarole field of the South Area has been relatively stable around 2 MW until February 2015. Their apparent temperatures were fluctuating around 490-575 °C before the major Strombolian explosive event, whereas those recorded at the active vent, named Central Pit, reached their maxima slightly above 600 °C; then both exhibited a decreasing trend in the following days. During the Strombolian activity, the crater lake dried out and was then replenished by early July, 2016. Then, volcanic activity shifted back to phreatic-phreatomagmatic and the eruptive cycle was completed. During this period, the MIROVA system detected very few thermal alerts and the ground-based measurements were fluctuating around 1 MW. The most violent explosion occurred on October 8, 2016, and within the following weeks measured VRP were moderately above 2 MW. This is coeval with a thermal increase at the fumarole field of the South Area, with temperatures well above 300 °C. Thermal monitoring at Aso Volcano is an additional tool in volcano surveillance that may contribute to near-real-time hazard assessment.[Figure not available: see fulltext.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70136288','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70136288"><span>Two magma bodies beneath the summit of Kilauea Volcano unveiled by isotopically distinct melt deliveries from the mantle</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Pietruszka, Aaron J.; Heaton, Daniel E.; Marske, Jared P.; Garcia, Michael O.</p> <p>2015-01-01</p> <p>The summit magma storage reservoir of Kīlauea Volcano is one of the most important components of the magmatic plumbing system of this frequently active basaltic shield-building volcano. Here we use new high-precision Pb isotopic analyses of Kīlauea summit lavas—from 1959 to the active Halema‘uma‘u lava lake—to infer the number, size, and interconnectedness of magma bodies within the volcano's summit reservoir. From 1971 to 1982, the 206Pb/204Pb ratios of the lavas define two separate magma mixing trends that correlate with differences in vent location and/or pre-eruptive magma temperature. These relationships, which contrast with a single magma mixing trend for lavas from 1959 to 1968, indicate that Kīlauea summit eruptions since at least 1971 were supplied from two distinct magma bodies. The locations of these magma bodies are inferred to coincide with two major deformation centers identified by geodetic monitoring of the volcano's summit region: (1) the main locus of the summit reservoir ∼2–4 km below the southern rim of Kīlauea Caldera and (2) a shallower magma body <2 km below the eastern rim of Halema‘uma‘u pit crater. Residence time modeling suggests that the total volume of magma within Kīlauea's summit reservoir during the late 20th century (1959–1982) was exceedingly small (∼0.1–0.5 km3). Voluminous Kīlauea eruptions, such as the ongoing, 32-yr old Pu‘u ‘Ō‘ō rift eruption (>4 km3 of lava erupted), must therefore be sustained by a nearly continuous supply of new melt from the mantle. The model results show that a minimum of four compositionally distinct, mantle-derived magma batches were delivered to the volcano (at least three directly to the summit reservoir) since 1959. These melt inputs correlate with the initiation of energetic (1959 Kīlauea Iki) and/or sustained (1969–1974 Mauna Ulu, 1983-present Pu‘u ‘Ō‘ō and 2008-present Halema‘uma‘u) eruptions. Thus, Kīlauea's eruptive behavior is partly tied to the delivery of new magma batches from the volcano's source region within the Hawaiian mantle plume.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70197333','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70197333"><span>Gas and ash emissions associated with the 2010–present activity of Sinabung Volcano, Indonesia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Primulyana, Sofyan; Kern, Christoph; Lerner, Allan; Saing, Ugan; Kunrat, Syegi; Alfianti, Hilma; Marlia, Mitha</p> <p>2017-01-01</p> <p>Sinabung Volcano (Sumatra, Indonesia) awoke from over 1200 years of dormancy with multiple phreatic explosions in 2010. After a period of quiescence, Sinabung activity resumed in 2013, producing frequent explosions, lava dome extrusion, and pyroclastic flows from dome collapses, becoming one of the world's most active volcanoes and displacing over 20,000 citizens. This study presents a compilation of the geochemical datasets collected by the Indonesian Center for Volcanology and Geological Hazard Mitigation (CVGHM) from 2010 - current (2016), which provides insights into the evolution of the eruption. Based on observations of SO2 emissions, ash componentry, leachate chemistry, and bulk ash geochemistry, the eruption can be split into five distinct phases. The initial stage of phreatic summit explosions occurred from August - October 2010, during which background SO2 emissions averaged ~550 ± 180 t/d (1 s.d.). An eruptive pause (phase two) starting in October 2010 abruptly ended in September 2013 with a resumption of conduit-clearing eruptions. This third phase had a relatively modest background SO2 emission rate (avg. ~410 ± 275 t/d) and produced ash consisting entirely of accidental ejecta with high S/Cl leachate ratios (up to 30), suggestive of deep-sourced magma and the incorporation of hydrothermal sulfur-bearing phases. The most intense phase of the eruption (phase four) occurred from December 2013 to February 2014, when juvenile magma first reached the surface. This period included dozens of large eruptions per day, high SO2 emission rates (average: 1,120 ± 1,030 t/d, peak: ~3,800 t/d), the onset of lava dome extrusion, and a dramatic drop in S/Cl ash leachates to ratios < 5, all reflecting increased degassing from shallow magma and the clearing out of sulfurous phases from the old hydrothermal system. From late February 2014 through the time of writing (September 2016), Sinabung settled into a relatively steady state of lower activity (phase five). Ash emissions now consist of dominantly juvenile material, and background SO2 emission rates have been progressively decreasing to an average of ~250 - 300 t/d. Starting August 2016, SO2 emissions started being measured in a continuous manner using a network of permanent scanning DOAS instruments. We find that long-term SO2 emission rates have been gradually declining at Sinabung since early 2014, consistent with an apparent decrease in magma supply. Our degassing model suggests that large explosions and pyroclastic flows could continue in the near-term owing to conduit plugging and dome collapses, remaining a major threat until the magma supply rate decreases further and the eruption ends.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.7582C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.7582C"><span>Joint analysis of deformation, gravity, and lava lake elevation reveals temporal variations in lava lake density at Kilauea Volcano, Hawaii</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carbone, Daniele; Poland, Michael; Patrick, Matthew</p> <p>2015-04-01</p> <p>We find a tight correlation between (i) changes in lava level within the summit eruptive vent at Kilauea Volcano, Hawaii, observed for at least 2 years since early 2011, and (ii) ground deformation in the vicinity of the vent. The observed correlation indicates that changing pressure within the shallow magma reservoir feeding the lava lake influences both deformation and lava level. However, those two parameters are related to chamber pressure through different properties, namely, the density of the lava filling the vent (for the lava level) and the size/position of the reservoir plus the elastic parameters of the host rock (for the deformation). Joint analyses in the time and frequency domains of lava level (determined from thermal camera imagery of the lava lake) and tilt measured on a borehole instrument (~2 km from the summit vent) reveal a good correlation throughout the studied period. The highest correlation occurs over periods ranging between 1 and 20 days. The ratio between lava level and tilt is not constant over time, however. Using data from a continuously recording gravimeter located near the rim of the summit eruptive vent, we demonstrate that the tilt-lava level ratio is controlled by the fluctuations in the density of the lava inside the vent (i.e., its degree of vesicularity). A second continuous gravimeter was installed near the summit eruptive vent in 2014, providing a new observation point for gravity change associated with summit lava lave activity to test models developed from the previously existing instrument. In addition, a continuous gravimeter was installed on the rim of the Puu Oo eruptive vent on Kilauea's East Rift Zone in 2013. Puu Oo is connected via the subvolcanic magma plumbing system to the summit eruptive vent and often deforms in concert with the summit. This growing network of continuously recording gravimeters at Kilauea can be used to examine correlations in gravity change associated with variations in eruptive activity across the volcano.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70019629','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70019629"><span>A dynamic balance between magma supply and eruption rate at Kilauea volcano, Hawaii</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Denlinger, R.P.</p> <p>1997-01-01</p> <p>The dynamic balance between magma supply and vent output at Kilauea volcano is used to estimate both the volume of magma stored within Kilauea volcano and its magma supply rate. Throughout most of 1991 a linear decline in volume flux from the Kupaianaha vent on Kilauea's east rift zone was associated with a parabolic variation in the elevation of Kilauea's summit as vent output initially exceeded then lagged behind the magma supply to the volcano. The correspondence between summit elevation and tilt established with over 30 years of data provided daily estimates of summit elevation in terms of summit tilt. The minimum in the parabolic variation in summit tilt and elevation (or zero elevation change) occurs when the magma supply to the reservoir from below the volcano equals the magma output from the reservoir to the surface, so that the magma supply rate is given by vent flux on that day. The measurements of vent flux and tilt establish that the magma supply rate to Kilauea volcano on June 19, 1991, was 217,000 ?? 10,000 m3/d (or 0.079 ?? 0.004 km3/yr). This is close to the average eruptive rate of 0.08 km3/yr between 1958 and 1984. In addition, the predictable response of summit elevation and tilt to each east rift zone eruption near Puu Oo since 1983 shows that summit deformation is also a measure of magma reservoir pressure. Given this, the correlation between the elevation of the Puu Oo lava lake (4 km uprift of Kupaianaha and 18 km from the summit) and summit tilt provides an estimate for magma pressure changes corresponding to summit tilt changes. The ratio of the change in volume to the change in reservoir pressure (dV/dP) during vent activity may be determined by dividing the ratio of volume erupted to change in summit tilt (dV/dtilt) by the ratio of pressure change to change in summit tilt (dP/dtilt). This measure of dV/dP, when combined with laboratory measurements of the bulk modulus of tholeitic melt, provides an estimate of 240 ?? 50 km3 for the volume of Kilauea's magma reservoir. This estimate is much larger than traditional estimates but consistent with seismic tomographic imaging and geophysical modeling of Kilauea's magma system. Copyright 1997 by the American Geophysical Union.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997JGR...10218091D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997JGR...10218091D"><span>A dynamic balance between magma supply and eruption rate at Kilauea volcano, Hawaii</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Denlinger, Roger P.</p> <p>1997-08-01</p> <p>The dynamic balance between magma supply and vent output at Kilauea volcano is used to estimate both the volume of magma stored within Kilauea volcano and its magma supply rate. Throughout most of 1991 a linear decline in volume flux from the Kupaianaha vent on Kilauea's east rift zone was associated with a parabolic variation in the elevation of Kilauea's summit as vent output initially exceeded then lagged behind the magma supply to the volcano. The correspondence between summit elevation and tilt established with over 30 years of data provided daily estimates of summit elevation in terms of summit tilt. The minimum in the parabolic variation in summit tilt and elevation (or zero elevation change) occurs when the magma supply to the reservoir from below the volcano equals the magma output from the reservoir to the surface, so that the magma supply rate is given by vent flux on that day. The measurements of vent flux and tilt establish that the magma supply rate to Kilauea volcano on June 19, 1991, was 217,000±10,000 m3/d (or 0.079±0.004 km3/yr). This is close to the average eruptive rate of 0.08 km3/yr between 1958 and 1984. In addition, the predictable response of summit elevation and tilt to each east rift zone eruption near Puu Oo since 1983 shows that summit deformation is also a measure of magma reservoir pressure. Given this, the correlation between the elevation of the Puu Oo lava lake (4 km uprift of Kupaianaha and 18 km from the summit) and summit tilt provides an estimate for magma pressure changes corresponding to summit tilt changes. The ratio of the change in volume to the change in reservoir pressure (dV/dP) during vent activity may be determined by dividing the ratio of volume erupted to change in summit tilt (dV/dtilt) by the ratio of pressure change to change in summit tilt (dP/dtilt). This measure of dV/dP, when combined with laboratory measurements of the bulk modulus of tholeitic melt, provides an estimate of 240±50 km3 for the volume of Kilauea's magma reservoir. This estimate is much larger than traditional estimates but consistent with seismic tomographic imaging and geophysical modeling of Kilauea's magma system.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JVGR..261..171J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JVGR..261..171J"><span>Signs of magma ascent in LP and VLP seismic events and link to degassing: An example from the 2010 explosive eruption at Merapi volcano, Indonesia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jousset, Philippe; Budi-Santoso, Agus; Jolly, Arthur D.; Boichu, Marie; Surono; Dwiyono, S.; Sumarti, Sri; Hidayati, Sri; Thierry, Pierre</p> <p>2013-07-01</p> <p>The link between seismicity and degassing is investigated during the VEI 4 eruptions of Merapi volcano (Indonesia) in October and in early November 2010. Seismicity comprised a large number and variety of earthquakes including Volcano-Tectonic events, a sustained period of Long Period Seismicity (LPS), i.e., Long-Period events (LP), Very Long Period events (VLP) and tremor. LPS seismicity is ascribed to the excitation of fluid-filled cavity resonance and inertial displacement of fluids and magma. We investigate here LPS that occurred between 17 October and 4 November 2010 to obtain insights into the volcano eruption processes which preceded the paroxysmal phase of the eruption on 4-5 November. We proceed to the moment tensor inversion of a well-recorded large VLP event during the intrusion phase on 17 October 2010, i.e., before the first explosion on 26 October. By using two simplified models (crack and pipe), we find a shallow source for this VLP event at about 1 km to the south of the summit and less than 1 km below the surface. We analyze more than 90 LP events that occurred during the multi-phase eruption (29 October-4 November). We show that most of them have a dominant frequency in the range 0.2-4 Hz. We could locate 48 of those LP events; at least 3 clusters of LP events occurred successively. We interpret these observations as generated by different fluid-filled containers in the summit area that were excited while magma rose. We also observe significant variations of the complex frequency during the course of the eruption. We discuss these changes in terms of a variable ratio of fluid to solid densities and/or by possible conduit geometry change and/or permeability of the conduit or the edifice and/or by resonance of different fluid-containers during the release of more than 0.4 Tg of SO2 and large but unknown masses of other volcanic gases. Finally, we also discuss how the major explosions of the eruption were possibly triggered by passing waves resulting from regional tectonic earthquakes on 3 and 4 November.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JVGR..320..107G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JVGR..320..107G"><span>Mass and heat flux balance of La Soufrière volcano (Guadeloupe) from aerial infrared thermal imaging</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gaudin, Damien; Beauducel, François; Coutant, Olivier; Delacourt, Christophe; Richon, Patrick; de Chabalier, Jean-Bernard; Hammouya, Gilbert</p> <p>2016-06-01</p> <p>La Soufrière of Guadeloupe is an active volcano of Lesser Antilles that is closely monitored due to a high eruptive hazard potential. Since 1992 it exhibits a medium-level but sustained background hydrothermal activity with low-energy and shallow seismicity, hot springs temperature increase and high flux acidic gas fumaroles at the summit. The problem of estimating the heat balance and quantifying the evolution of hydrothermal activity has become a key challenge for surveillance. This work is the first attempt of a global mapping and quantification of La Soufrière thermal activity performed in February 2010 using aerial thermal infrared imagery. After instrument calibration and data processing, we present a global map of thermal anomalies allowing to spot the main active sites: the summit area (including the fumaroles of Tarissan Pit and South Crater), the Ty Fault fumarolic zone, and the hot springs located at the vicinity of the dome. In a second step, we deduce the mass and the energy fluxes released by the volcano. In particular, we propose a simple model of energy balance to estimate the mass flux of the summit fumaroles from their brightness temperature and size. In February 2010, Tarissan Pit had a 22.8 ± 8.1 kg s -1 flux (1970 ± 704 tons day -1), while South Crater vents had a total of 19.5 ± 4.0 kg s -1 (1687 ± 348 tons day -1). Once converted into energy flux, summit fumaroles represent 98% of the 106 ± 30 MW released by the volcano, the 2% remaining being split between the hot springs and the thermal anomalies at the summit and at the Ty Fault fumarolic zone. These values are in the high range of the previous estimations, highlighting the short-term variability of the expelled fluxes. Such a heat flux requires the cooling of 1500 m 3 of magma per day, in good agreement with previous geochemical studies.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-STS062-85-195.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-STS062-85-195.html"><span>Mt. Etna, Sicily as seen from STS-62</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>1994-03-05</p> <p>STS062-85-195 (4-18 March 1994) --- A thin plume of steam blows southward from the summit of Mt. Etna, the active volcano on the island of Sicily. The summit is capped with snow but the dark lava flow along the eastern flank (the 1991-93 flow) is clearly visible. The coastal city south of Etna is Catania.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70032987','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70032987"><span>Hydrothermal circulation at Mount St. Helens determined by self-potential measurements</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bedrosian, P.A.; Unsworth, M.J.; Johnston, M.J.S.</p> <p>2007-01-01</p> <p>The distribution of hydrothermal circulation within active volcanoes is of importance in identifying regions of hydrothermal alteration which may in turn control explosivity, slope stability and sector collapse. Self-potential measurements, indicative of fluid circulation, were made within the crater of Mount St. Helens in 2000 and 2001. A strong dipolar anomaly in the self-potential field was detected on the north face of the 1980-86 lava dome. This anomaly reaches a value of negative one volt on the lower flanks of the dome and reverses sign toward the dome summit. The anomaly pattern is believed to result from a combination of thermoelectric, electrokinetic, and fluid disruption effects within and surrounding the dome. Heat supplied from a cooling dacite magma very likely drives a shallow hydrothermal convection cell within the dome. The temporal stability of the SP field, low surface recharge rate, and magmatic component to fumarole condensates and thermal waters suggest the hydrothermal system is maintained by water vapor exsolved from the magma and modulated on short time scales by surface recharge. ?? 2006 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.V41A2771S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.V41A2771S"><span>Constraining the Dynamics of Periodic Behavior at Mt. Semeru, Indonesia, Combining Numerical Modeling and Field Measurements of Gas emission</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smekens, J.; Clarke, A. B.; De'Michieli Vitturi, M.; Moore, G. M.</p> <p>2012-12-01</p> <p>Mt. Semeru is one of the most active explosive volcanoes on the island of Java in Indonesia. The current eruption style consists of small but frequent explosions and/or gas releases (several times a day) accompanied by continuous lava effusion that sporadically produces block-and-ash flows down the SE flank of the volcano. Semeru presents a unique opportunity to investigate the magma ascent conditions that produce this kind of persistent periodic behavior and the coexistence of explosive and effusive eruptions. In this work we use DOMEFLOW, a 1.5D transient isothermal numerical model, to investigate the dynamics of lava extrusion at Semeru. Petrologic observations from tephra and ballistic samples collected at the summit help us constrain the initial conditions of the system. Preliminary model runs produced periodic lava extrusion and pulses of gas release at the vent, with a cycle period on the order of hours, even though a steady magma supply rate was prescribed at the bottom of the conduit. Enhanced shallow permeability implemented in the model appears to create a dense plug in the shallow subsurface, which in turn plays a critical role in creating and controlling the observed periodic behavior. We measured SO2 fluxes just above the vent, using a custom UV imaging system. The device consists of two high-sensitivity CCD cameras with narrow UV filters centered at 310 and 330 nm, and a USB2000+ spectrometer for calibration and distance correction. The method produces high-frequency flux series with an accurate determination of the wind speed and plume geometry. The model results, when combined with gas measurements, and measurements of sulfur in both the groundmass and melt inclusions in eruptive products, could be used to create a volatile budget of the system. Furthermore, a well-calibrated model of the system will ultimately allow the characteristic periodicity and corresponding gas flux to be used as a proxy for magma supply rate.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/71612','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/71612"><span>Volcanic gas emissions and their impact on ambient air character at Kilauea Volcano, Hawaii</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Sutton, A.J.; Elias, T.; Navarrete, R.</p> <p>1994-12-31</p> <p>Gas emissions from Kilauea occur from the summit caldera, along the middle East Rift Zone (ERZ), and where lava enters the ocean. We estimate that the current ERZ eruption of Kilauea releases between 400 metric tonnes of SO{sub 2} per day, during eruptive pauses, to as much as 1850 metric tonnes per day during actively erupting periods, along with lesser amounts of other chemically and radiatively active species including H{sub 2}S, HCl and HF. In order to characterize gas emissions from Kilauea in a meaningful way for assessing environmental impact, we made a series of replicate grab-sample measurements of ambientmore » air and precipitation at the summit of Kilauea, along its ERZ, and at coastal sites where lava enters the ocean. The grab-sampling data combined with SO{sub 2} emission rates, and continuous air quality and meteorological monitoring at the summit of Kilauea show that the effects of these emissions on ambient air character are a complex function of chemical reactivity, source geometry and effusivity, and local meteorology. Prevailing tradewinds typically carry the gases and aerosols released to the southwest, where they are further distributed by the regional wind regime. Episodes of kona, or low speed variable winds sometimes disrupt this pattern, however, and allow the gases and their oxidation products to collect at the summit and eastern side of the island. Summit solfatara areas of Kilauea are distinguished by moderate to high ambient SO{sub 2}, high H{sub 2}S at one location, and low H{sub 2}S at all others, and negligible HCl concentrations, as measured 1 m from degassing point-sources. Summit solfatara rain water has high sulfate and low chloride ion concentrations, and low pH.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.V23A0455R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.V23A0455R"><span>Geomorphological mapping using drones into the eruptive summit of Turrialba volcano, Costa Rica</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ruiz, P.; Mora, M.; Soto, G. J.; Vega, P.; Barrantes, R.</p> <p>2017-12-01</p> <p>We produced and compared two detailed topographic datasets of the SW active crater on the summit of Turrialba volcano (03/2016 and 06/2017). These datasets are based on hundreds of orthophotos obtained by low-height flights by drones (Phantom-3, and Inspire-1) to collect the aerial data, and ground control points from RTK-GPS surveys (for ground survey and control points, we used reflective marks and local stations). Photogrammetry software and GIS were used to processes the data for creating DEMs. Using these data, we have been able to document the geomorphological changes generated by eruptions. We have learned the processes involved in the crater evolution during an eruption period passing from a close-system to an open one. Turrialba has been erupting since 2010, when a phreatic explosion opened a small vent on the SW crater. Further minor phreatic eruptions occurred in 2011-2013 with a slow increase of juvenile content in its products, until it clearly evolved to phreatomagmatism in 2014 and an open-system in mid-2016. We recorded significant changes in the morphology of the active crater in the latest period of eruption. These changes are the result of stronger eruptions between 04/2016 and 01/2017, finally clearing the main conduit that opened the system and favored the rise of magma up to the surface. Lava now lies on the bottom of the crater, forming a small lava pool (25m x 15m). We found that in the 15-month period during the opening of the volcanic system, the active crater got 100 m deeper and wider at the bottom (in 06/2017, depth was 230 m, and the empty volume of the crater 2.5x106m3. These observations are consistent with the seismic records through the opening of the system and the eruption style. Aerial dataset from low-height flights by drones are a powerful tool to understand the evolution of volcanoes from close to open systems and for volcano hazard assessments.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUSM.V23A..01M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUSM.V23A..01M"><span>Origin and age of the Volcanic Rocks of Tláloc Volcano, Sierra Nevada, Central Mexico</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meier, M.; Grobéty, B.; Arce, J. L.; Rueda, H.</p> <p>2007-05-01</p> <p>The Tláloc volcano (TV) is a 4125 m high stratovolcano of the Trans Mexican Volcanic Belt (TMVB) and is located in the northern end of the N-S trending Sierra Nevada, 30 km NE of Mexico City. Few data on the petrological and temporal evolution of TV have been published to date. Recently dated deposits gave ages between 32'000 and 34'500±500 years BP (Huddart and Gonzalez, 2004). Mapping and sampling of extrusive rocks in the summit region of TV revealed a dome structure with radiating lava flows consisting of dacitic rocks containing plagioclase and hornblende phenocrysts. Some flows, however, seem to be associated with a collapse structure E of the main summit. Crossing relationships indicate that this structure is older (“Paleo Tláloc”). A stratigraphy of the pyroclastic deposits was established along the northern slope of TV. From the numerous pyroclastic flows, separated by paleosoils and fluviatile deposits, only two pumice and one block and ash flow (BAF) have regional extent. Their thickness - distance relationship and their granulometry point to major explosive events. A carbonized wood sample from the BAF deposit gave ages similar to the previous ages (33'180±550 yr BP and 23'170±270 yr BP), a sample from a pyroclastic flow gave even a younger age (16'620±110 yr BP), suggesting that TV remained active also after the volcanoes Iztaccíhuatl and Popocatépetl further to the South started their activity. Based on these preliminary data it may be necessary to reconsider the accepted scenario of the temporal evolution of the central section of the TMVB, which assumes that the activity migrates from North to South with time. Huddart, D. and Gonzalez, S., 2004. Pyroclastic flows and associated sediments, Tláloc-Telapón, piedmont fringe of the eastern basin of Mexico. In: G.J. Aguirre-Diaz, Macías, J.L., and Siebe, C., (Editor), Penrose Conference. UNAM, Metepec, Puebla, Mexico, pp. 35.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss015e16913.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss015e16913.html"><span>Earth Observations taken by the Expedition 15 Crew</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2007-07-10</p> <p>ISS015-E-16913 (10 July 2007) --- Shiveluch Volcano, Kamchatka, Russian Far East is featured in this image photographed by an Expedition 15 crewmember on the International Space Station. Shiveluch is one of the biggest and most active of a line of volcanoes along the spine of the Kamchatka peninsula in easternmost Russia. In turn the volcanoes and peninsula are part of the tectonically active "Ring of Fire" that almost surrounds the Pacific Ocean, denoted by active volcanoes and frequent earthquakes. Shiveluch occupies the point where the northeast-trending Kamchatka volcanic line intersects the northwest-trending Aleutian volcanic line. Junctions such as this are typically points of intense volcanic activity. According to scientists, the summit rocks of Shiveluch have been dated at approximately 65,000 years old. Lava layers on the sides of the volcano reveal at least 60 major eruptions in the last 10,000 years, making it the most active volcano in the 2,200 kilometer distance that includes the Kamchatka peninsula and the Kuril island chain. Shiveluch rises from almost sea level to well above 3,200 miles (summit altitude 3,283 miles) and is often capped with snow. In this summer image however, the full volcano is visible, actively erupting ash and steam in late June or early July, 2007. The dull brown plume extending from the north of the volcano summit is most likely a combination of ash and steam (top). The two larger white plumes near the summit are dominantly steam, a common adjunct to eruptions, as rain and melted snow percolate down to the hot interior of the volcano. The sides of the volcano show many eroded stream channels. The south slope also reveals a long sloping apron of collapsed material, or pyroclastic flows. Such debris flows have repeatedly slid down and covered the south side of the volcano during major eruptions when the summit lava domes explode and collapse (this occurred during major eruptions in 1854 and 1964). Regrowth of the forest on the south slope (note the contrast with the eastern slope) has been foiled by the combined effects of continued volcanic activity, instability of the debris flows and the short growing season.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA22159.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA22159.html"><span>Investigating Mars: Arsia Mons</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2018-01-05</p> <p>This THEMIS image shows part of the southern margin of the summit caldera. This image contains a variety of features representing the major events related to the formation of the volcano. At the top of the image a small linear vent has produced lava flows increasing the elevation of the surface around it. The flat floor of the caldera surrounds the vent and the cliff faces at the center of the image were created during the collapse event that formed the caldera. Depressions at the bottom illustrate collapse into empty voids like lava tubes. Arsia Mons is the southernmost of the Tharsis volcanoes. It is 270 miles (450 km) in diameter, almost 12 miles (20 km) high, and the summit caldera is 72 miles (120 km) wide. For comparison, the largest volcano on Earth is Mauna Loa. From its base on the sea floor, Mauna Loa measures only 6.3 miles high and 75 miles in diameter. A large volcanic crater known as a caldera is located at the summit of all of the Tharsis volcanoes. These calderas are produced by massive volcanic explosions and collapse. The Arsia Mons summit caldera is larger than many volcanoes on Earth. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 63900 Latitude: -10.0873 Longitude: 239.197 Instrument: VIS Captured: 2016-05-10 07:58 https://photojournal.jpl.nasa.gov/catalog/PIA22159</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.S11E4385F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.S11E4385F"><span>Full waveform ambient noise tomography of Mount Rainer</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Flinders, A. F.; Shen, Y.</p> <p>2014-12-01</p> <p>Mount Rainier towers over the landscape of western Washington, ranking with Fuji-yama in Japan, Mt. Pinatubo in the Philippines, and Mt. Vesuvius in Italy, as one of the great stratovolcanoes of the world. Notwithstanding it's picturesque stature, Mt. Rainier is potentially the most devastating stratovolcano in North America, with more than 3.5 million people living beneath its shadow in the Seattle-Tacoma area. The primary hazard posed by the volcano is in the form of highly destructive volcanic debris flows (lahars). These lahars form when water and/or melted ice erode away and entrain preexisting volcanic sediment. At Mt. Rainier these flows are often initiated by sector collapse of the volcano's hydrothermally rotten flanks and compounded from Mt. Rainier's extensive snow and glacial ice coverage. It is therefore imperative to ascertain the extent of summit hydrothermal alteration within the volcano, and determine areas prone to collapse. Despite being one of the sixteen volcanoes globally designated by the International Association of Volcanology and Chemistry of the Earth's Interior as warranting detailed and focused study, Mt. Rainier remains enigmatic both in terms of shallow internal structure and the degree of summit hydrothermal alteration. We image this shallow internal structure and areas of possible summit alteration using ambient noise tomography. Our full waveform forward modeling includes high-resolution topography, allowing us to accurately account for the effects of topography on the propagation of short-period Rayleigh waves. Empirical Green's functions were extracted from 80 stations within 200 km of Mount Rainier and compared with synthetic greens functions over multiple frequency bands from 2-28 seconds. The preliminary model shows a broad (60 km wide) low shear-wave velocity anomaly in the mid-crust beneath the volcano. The mid-crust low-velocity body extends to the surface beneath the volcano summit in a narrow near-vertical conduit, the likely path of magma ascent. There is a peculiar aseismic high Vs and low Vp/Vs zone (possibly indicative of a high quartz bearing lithology) beneath the eastern edifice. We interpret it as a possible remnant of a more felsic (and perhaps more explosive) proto Mount Rainier volcano.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.V41A2486K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.V41A2486K"><span>Magma transport and storage at Kilauea volcano, Hawaii II: 1952-2008</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Klein, F.; Wright, T. L.</p> <p>2011-12-01</p> <p>We trace the evolution of Kilauea between the Halemaumau eruptions of 1952 and 2008. The magma supply path from the mantle is defined by the distribution of earthquakes deeper than 20 km. We compared the accumulated moment release from deep magma supply, south flank and rift zone earthquakes. We identified every intrusion and eruption in time plots of summit tilt and seismic activity in all regions, and plotted the earthquake distribution for ~ 1 week covering the period prior to, during and following the event. The establishment and continued growth of modern seismic and geodetic networks allow us to define three types of intrusions. 'Normal' intrusions occur with or without eruption and are accompanied by sharp tilt deflation at Kilauea's summit. 'Inflationary' intrusions occur during periods of summit inflation accompanied by rift earthquake swarms in the near-summit parts of both rift zones. 'Slow' intrusions are defined by isolated swarms of south flank earthquakes distributed perpendicular to the rift zones. Magnitudes of inflation and deflation shown by the daily tilt record at Kilauea's summit are converted to volume using a factor determined by previous workers. Magma supply rates are determined by summation of the volumes in cubic kilometers of (1) net summit inflation (2) sharp summit deflation accompanying rift activity and (3) summit and long continuous rift eruptions, divided by the elapsed time in years. Eruption efficiency is calculated by comparing the volumes of rift eruption and summit deflation. In this study we have reached the following conclusions: 1) Magma supply rates have increased from the pre-1952 value of 0.062 km3/yr to 0.1 km3/yr during the Mauna Ulu eruption of 1969-74 to 0.2 km3/yr during much of the eruption that began in 1983. 2) Eruption efficiencies show cyclic increases with increased activity, culminating in an efficiency averaging 100% during episodes of high fountaining in the period 1983-86. 3) Some south flank earthquake swarms herald rift earthquake swarms associated with rift eruption and intrusion by minutes to hours, consistent with the existence of a deep pressure-transmitting magma system beneath the rift zones. 4) Seaward movement and rift dilation during the M 7.2 earthquake on Nov. 29, 1975 changed the volcano's behavior. Before the 1975 earthquake, magma supply drove flank spreading. Following the earthquake, spreading rates were similar to the time before the earthquake but the magma supply rate increased partly because the flank was de-stressed and new magma was unconstrained by the flank. 5) Recent slow intrusions have a seismic signature that matches 'slow' or 'silent' earthquakes and we suggest that such events date from the 1960s. 6) The effects of Mauna Loa on Kilauea and vice versa are manifested in the increased magma supply rate at Kilauea since 1952 and the decreased Mauna Loa activity since 1950, a pattern also seen in the 19th century and earlier. This relationship is further emphasized by the lack of any Mauna Loa eruption since Kilauea began continuous eruption in 1983. We interpret Kilauea's long history as one of crisis and recovery. Crises are anticipated by increased seismic activity and recovery is associated with major changes in volcano behavior.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRB..121.5425Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRB..121.5425Z"><span>Spatiotemporal model of Kīlauea's summit magmatic system inferred from InSAR time series and geometry-free time-dependent source inversion</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhai, Guang; Shirzaei, Manoochehr</p> <p>2016-07-01</p> <p>Kīlauea volcano, Hawai`i Island, has a complex magmatic system including summit reservoirs and rift zones. Kinematic models of the summit reservoir have so far been limited to first-order analytical solutions with predetermined geometry. To explore the complex geometry and kinematics of the summit reservoir, we apply a multitrack wavelet-based InSAR (interferometric synthetic aperture radar) algorithm and a novel geometry-free time-dependent modeling scheme. To map spatiotemporally distributed surface deformation signals over Kīlauea's summit, we process synthetic aperture radar data sets from two overlapping tracks of the Envisat satellite, including 100 images during the period 2003-2010. Following validation against Global Positioning System data, we invert the surface deformation time series to constrain the spatiotemporal evolution of the magmatic system without any prior knowledge of the source geometry. The optimum model is characterized by a spheroidal and a tube-like zone of volume change beneath the summit and the southwest rift zone at 2-3 km depth, respectively. To reduce the model dimension, we apply a principal component analysis scheme, which allows for the identification of independent reservoirs. The first three PCs, explaining 99% (63.8%, 28.5%, and 6.6%, respectively) of the model, include six independent reservoirs with a complex interaction suggested by temporal analysis. The data and model presented here, in agreement with earlier studies, improve the understanding of Kīlauea's plumbing system through enhancing the knowledge of temporally variable magma supply, storage, and transport beneath the summit, and verify the link between summit magmatic activity, seismicity, and rift intrusions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015IAUGA..2227893P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015IAUGA..2227893P"><span>The 2015 Chile-U.S. Astronomy Education Outreach Summit in Chile</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Preston, Sandra Lee; Arnett, Dinah; Hardy, Eduardo; Cabezón, Sergio; Spuck, Tim; Fields, Mary Sue; Smith, R. Chris</p> <p>2015-08-01</p> <p>The first Chile-U.S. Astronomy Education Outreach Summit occurred March 22-28, 2015. The Summit was organized and supported by the U.S. Embassy in Chile, Associated Universities Inc., Association of Universities for Research in Astronomy, the Carnegie Institution for Science, the Image of Chile Foundation, the National Science Foundation, and La Comisión Nacional de Investigación Científica y Tecnológica. The Summit brought together a team of leading experts and officials from Chile and the U.S. to share best practices in astronomy education and outreach. In addition, Summit participants discussed enhancing existing partnerships, and building new collaborations between U.S. Observatories and astronomy education outreach leaders in Chile.The Summit was an exciting and intense week of work and travel. Discussions opened in Santiago on March 22 with a variety of astronomy education and public outreach work sessions, a public forum, and on March 23 the U.S. Embassy sponsored a Star Party. On Tuesday, March 24, the Summit moved to San Pedro de Atacama, where activities included work sessions, a visit to the Atacama Large Millimeter/Submillimeter Array telescope facilities, and a second public forum. From San Pedro, the team traveled to La Serena for additional work sessions, visits to Gemini and Cerro Tololo, a third public forum, and the closing session. At each stop, authorities and the broader community were invited to participate and provide valuable input on the current state, and the future, of astronomy education and public outreach.Following the Summit a core working committee has continued meeting to draft a “roadmap document” based on findings from the Summit. This document will help to identify potential gaps in astronomy outreach efforts, and how the U.S. facilities and Chilean institutions might work together strategically to address these needs. The first draft of this “roadmap document” will be made available for comment in both Spanish and English in late September 2015.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17809214','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17809214"><span>Summit firn caves, mount rainier, washington.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kiver, E P; Mumma, M D</p> <p>1971-07-23</p> <p>Heat and steam from the crater fumaroles have melted over 5700 feet (1737 meters) of cave passage in the ice-filled east crater of Mount Rainier. The caves are in approximate balance with the present geothermal heat release. Future changes in the thermal activity of the summit cone will cause corresponding changes in cave passage dimensions, location, and ceiling and wall ablation features.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss005e18511.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss005e18511.html"><span>Crew Earth Observations (CEO) by Expedition Five Crew</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2002-10-25</p> <p>ISS005-E-18511 (25 October 2002) --- Mount Saint Helens, Washington, is featured in this image photographed by an Expedition 5 crewmember on the International Space Station (ISS). On May 18, 1980, Mount Saint Helens volcano erupted. A series of earthquakes preceded the eruption, triggering a collapse of the north side of the mountain into a massive landslide. This avalanche coincided with a huge explosion that destroyed over 270 square miles of forest in a few seconds, and sent a billowing cloud of ash and smoke 80,000 feet into the atmosphere. The crewmembers on the Station captured this detailed image of the volcanos summit caldera. In the center of the crater sits a lava dome that is 876 feet above the crater floor and is about 3,500 feet in diameter. The upper slopes of the 1980 blast zone begin at the gray colored region that extends north (upper left) from the summit of the volcano. The deeply incised valley to the left (west) is the uppermost reach of the South Fork of the Toutle River. Devastating mudslides buried the original Toutle River Valley to an average depth of 150 feet, but in places up to 600 feet. The dark green area south of the blast zone is the thickly forested region of the Gifford Pinchot National Forest.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MarGR..38..169Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MarGR..38..169Z"><span>Morphology of Shatsky Rise oceanic plateau from high resolution bathymetry</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Jinchang; Sager, William W.; Durkin, William J.</p> <p>2017-06-01</p> <p>Newly collected, high resolution multi-beam sonar data are combined with previous bathymetry data to produce an improved bathymetric map of Shatsky Rise oceanic plateau. Bathymetry data show that two massifs within Shatsky Rise are immense central volcanoes with gentle flank slopes declining from a central summit. Tamu Massif is a slightly elongated, dome-like volcanic edifice; Ori Massif is square shaped and smaller in area. Several down-to-basin normal faults are observed on the western flank of the massifs but they do not parallel the magnetic lineations, indicating that these faults are probably not related to spreading ridge faulting. Moreover, the faults are observed only on one side of the massifs, which is contrary to expectations from a mechanism of differential subsidence around the massif center. Multi-beam data show many small secondary cones with different shapes and sizes that are widely-distributed on Shatsky Rise massifs, which imply small late-stage magma sources scattered across the surface of the volcanoes in the form of lava flows or explosive volcanism. Erosional channels occur on the flanks of Shatsky Rise volcanoes due to mass wasting and display evidence of down-slope sediment movement. These channels are likely formed by sediments spalling off the edges of summit sediment cap.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.4771K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.4771K"><span>Temporal variations of randomness in seismic noise during the 2009 Redoubt volcano eruption, Cook Inlet, Alaska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Konstantinou, Konstantinos; Glynn, Chagnon</p> <p>2017-04-01</p> <p>Redoubt volcano is a stratovolcano in the Cook Inlet, south-central Alaska, that has erupted several times in the last fifty years. Its latest eruption in March 2009 was preceded first by volcanic tremor, which was immediately followed by a swarm of low-frequency earthquakes. Due to its proximity to sensitive infrastructure (oil platforms and storage facilities) and the fact that it lies in the way of air traffic routes, Redoubt has been closely monitored by permanent and temporary seismic stations. One of these stations (REF) equipped with a short-period, vertical component sensor was located very near the summit and was continuously recording before, during and after the 2009 eruption. Here we quantify the randomness levels of the continuous seismic signal at REF by calculating Permutation Entropy (PE), which is a nonlinear statistical measure of the amount of randomness in a time series. The time window for this calculation starts 1 January 2009 about two months before the first earthquake swarm, and ends 2 May 2009 when the main explosive activity ceased. The temporal variation of PE during this period shows two significant features: (1) a large decrease about 20 days prior to the onset of the earthquake swarm of 26 February, and (2) smaller decreases that occur shortly (few hours to a day) before phreatic/magmatic explosions. These decreases in PE also coincide with depletion of higher frequencies (> 6 Hz) in the seismic signal, confirming previous findings where reduced randomness in seismic noise may indicate increased absorption losses as hot magmatic fluids reach shallow levels within the volcano edifice.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.V13D2884G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.V13D2884G"><span>From mantle to ash cloud: quantifying magma generation, ascent, and degassing rates at Kilauea during short-lived explosive episodes using short-lived U-series radionuclide disequilibria</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Girard, G.; Reagan, M. K.; Sims, K. W.; Garcia, M. O.; Pietruszka, A. J.; Thornber, C. R.</p> <p>2012-12-01</p> <p>We analyzed for 238U-series isotopes lava, scoria and ash samples erupted from Kilauea volcano, Hawai'i between 1982 and 2008, in order to investigate processes and timescales of magma generation in the mantle, magma ascent through the crust, and eruption. Timescales of degassing during steady-state lava flow activity occurring in Kilauea East Rift Zone and short-lived explosive episodes that occurred in both the East Rift Zone (Pu'u 'O'o vent opening in 1983 and episode 54 at Nāpau crater in January 1997) and on the summit (Halema'uma'u crater eruptions in March 2008) are compared and contrasted. All samples were found to have small but variable 230Th and 226Ra activity excesses over 238U and 230Th, respectively, with (230Th/238U) ratios ranging from 1.00 to 1.13 and (226Ra/230Th) ratios ranging from 1.03 to 1.17. These two variable isotopic disequilibria may reflect local heterogeneities in the mantle underneath Kilauea, with sources in relatively primitive mantle with (238U)-(230Th)-(226Ra) in secular equilibrium and in recently (< 8000 years) depleted mantle with (230Th) and (226Ra) deficits over parent nuclides. In this model, both types of mantle melt to generate Kilauea magmas and subsequently mix in variable proportions. Samples from the brief explosive episodes span the entire composition range, suggesting that they were fed by heterogeneous magma batches which did not homogenize during ascent from the mantle. (210Pb/226Ra) ratios range from 0.75 to 1.00. The lack of correlation between (210Pb/226Ra) and (226Ra/230Th) or (230Th/238U), and the rapid return to secular equilibrium of 210Pb (< 100 years) suggest a fractionation process distinct from and subsequent to the Ra-Th-U fractionation inherited from mantle melting. We hypothesize that 210Pb deficits originate from 222Rn degassing during magma ascent, and estimate magma ascent from lower crust to surface to take place in a maximum of ~ 7 years for the lava flow samples. Products from the explosive episodes have ratios from ~ 0.75 to near equilibrium, suggesting that they comprise of a mix of young melts and degassed magmas which were stored in the shallow volcanic edifice for a few decades, in agreement with existing petrologic models.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sim/2007/2936/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sim/2007/2936/"><span>Geologic Map of the MTM -30262 and -30267 Quadrangles, Hadriaca Patera Region of Mars</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Crown, David A.; Greeley, Ronald</p> <p>2007-01-01</p> <p>Introduction Mars Transverse Mercator (MTM) -30262 and -30267 quadrangles cover the summit region and east margin of Hadriaca Patera, one of the Martian volcanoes designated highland paterae. MTM -30262 quadrangle includes volcanic deposits from Hadriaca Patera and Tyrrhena Patera (summit northeast of map area) and floor deposits associated with the Dao and Niger Valles canyon systems (south of map area). MTM -30267 quadrangle is centered on the caldera of Hadriaca Patera. The highland paterae are among the oldest, central-vent volcanoes on Mars and exhibit evidence for explosive eruptions, which make a detailed study of their geology an important component in understanding the evolution of Martian volcanism. Photogeologic mapping at 1:500,000-scale from analysis of Viking Orbiter images complements volcanological studies of Hadriaca Patera, geologic investigations of the other highland paterae, and an analysis of the styles and evolution of volcanic activity east of Hellas Planitia in the ancient, cratered highlands of Mars. This photogeologic study is an extension of regional geologic mapping east of Hellas Planitia. The Martian highland paterae are low-relief, areally extensive volcanoes exhibiting central calderas and radial channels and ridges. Four of these volcanoes, Hadriaca, Tyrrhena, Amphitrites, and Peneus Paterae, are located in the ancient cratered terrains surrounding Hellas Planitia and are thought to be located on inferred impact basin rings or related fractures. Based on analyses of Mariner 9 images, Potter (1976), Peterson (1977), and King (1978) suggested that the highland paterae were shield volcanoes formed by eruptions of fluid lavas. Later studies noted morphologic similarities between the paterae and terrestrial ash shields and the lack of primary lava flow features on the flanks of the volcanoes. The degraded appearances of Hadriaca and Tyrrhena Paterae and the apparently easily eroded materials composing their low, broad shields further suggest that the highland paterae are composed predominantly of pyroclastic deposits. Analyses of eruption and flow processes indicate that the distribution of units at Hadriaca and Tyrrhena Paterae is consistent with emplacement by gravity-driven pyroclastic flows. Detailed geologic study of the summit caldera and flanks of Hadriaca Patera is essential to determine the types of volcanic materials exposed, the nature of the processes forming these deposits, and the role of volcanism in the evolution of the cratered highlands that are characteristic of the southern hemisphere of Mars.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.V33E..01P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.V33E..01P"><span>Recent improvements in monitoring Hawaiian volcanoes with webcams and thermal cameras</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Patrick, M. R.; Orr, T. R.; Antolik, L.; Lee, R.; Kamibayashi, K.</p> <p>2012-12-01</p> <p>Webcams have become essential tools for continuous observation of ongoing volcanic activity. The use of both visual webcams and Web-connected thermal cameras has increased dramatically at the Hawaiian Volcano Observatory over the past five years, improving our monitoring capability and understanding of both Kilauea's summit eruption, which began in 2008, and the east rift zone eruption, which began in 1983. The recent bolstering of the webcam network builds upon the three sub-megapixel webcams that were in place five years ago. First, several additional fixed visual webcam systems have been installed, using multi-megapixel low-light cameras. Second, several continuously operating thermal cameras have been deployed, providing a new view of activity, easier detection of active flows, and often "seeing" through fume that completely obscures views from visual webcams. Third, a new type of "mobile" webcam - using cellular modem telemetry and capable of rapid deployment - has allowed us to respond quickly to changes in eruptive activity. Fourth, development of automated analysis and alerting scripts provide real-time products that aid in quantitative interpretation of incoming images. Finally, improvements in the archiving and Web-based display of images allow efficient review of current and recent images by observatory staff. Examples from Kilauea's summit and lava flow field provide more detail on the improvements. A thermal camera situated at Kilauea's summit has tracked the changes in the active lava lake in Halema`uma`u Crater since late 2010. Automated measurements from these images using Matlab scripts are now providing real-time quantitative data on lava level and, in some cases, lava crust velocity. Lava level essentially follows summit tilt over short time scales, in which near-daily cycles of deflation and inflation correspond with about ten meters of lava level drop and rise, respectively. The data also show that the long-term Halema`uma`u lava level tracked by the thermal cameras also correlates with the pressure state of the summit magma reservoir over months based on deformation data. Comparing the summit lava level with that in Pu`u `O`o crater, about 20 km distant on the east rift zone, reveals a clear correlation that reaffirms the hydraulic connection from summit to rift zone. Elsewhere on Kilauea, mobile webcams deployed on the coastal plain have improved the tracking of active breakouts from the east rift zone eruption site - a critical hazard zone given that four homes, mostly in the Kalapana area, have been destroyed by lava flows in the last three years. Each morning an automated Matlab script detects incandescent areas in overnight images and, using the known image geometry, determines the azimuth to active flows. The results of this eruptive "breakout locator" are emailed to observatory staff each morning and provide a quantitative constraint on breakout locations and hazard potential that serves as a valuable addition to routine field mapping. These examples show the utility of webcams and thermal cameras for monitoring volcanic activity, and they reinforce the importance of continued development of equipment as well as real-time processing and analysis tools.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70159596','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70159596"><span>Lava lake level as a gauge of magma reservoir pressure and eruptive hazard</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Patrick, Matthew R.; Anderson, Kyle R.; Poland, Michael P.; Orr, Tim R.; Swanson, Donald A.</p> <p>2015-01-01</p> <p>Forecasting volcanic activity relies fundamentally on tracking magma pressure through the use of proxies, such as ground surface deformation and earthquake rates. Lava lakes at open-vent basaltic volcanoes provide a window into the uppermost magma system for gauging reservoir pressure changes more directly. At Kīlauea Volcano (Hawaiʻi, USA) the surface height of the summit lava lake in Halemaʻumaʻu Crater fluctuates with surface deformation over short (hours to days) and long (weeks to months) time scales. This correlation implies that the lake behaves as a simple piezometer of the subsurface magma reservoir. Changes in lava level and summit deformation scale with (and shortly precede) changes in eruption rate from Kīlauea's East Rift Zone, indicating that summit lava level can be used for short-term forecasting of rift zone activity and associated hazards at Kīlauea.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.V11A0339F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.V11A0339F"><span>An Overview of Thermal Measurements (IR) at the Summit of Piton de la Fournaise Active Volcano and Inferences on the Structure and Dynamics of its Hydrothermal System</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fontaine, F.; Peltier, A.; Kowalski, P.; Di Muro, A.; Villeneuve, N.; Ferrazzini, V.; Staudacher, T.</p> <p>2017-12-01</p> <p>Piton de la Fournaise, located on La Réunion Island in the South East Indian Ocean, is one of the most active basaltic volcanoes (hotspot) of the world with a mean eruption frequency <6 months over the last 20 years. The central dome of the shield is thought to host an active hydrothermal system evidenced by self-potential techniques early in the 90's and mining heat from a magmatic source located about 2-2.5 km below the summit. Surface manifestations of this activity such as fumeroles or hot grounds have however never been observed before 2007 when deep magma withdrawal from the magmatic horizon during the "eruption of the century" (>100×106 m3) on the island, led to the formation of a 400-m-deep, 1000-m-large, funnel-shaped summit caldera. Since then, the floor and inner flanks of this summit depression hosting hot grounds and active fumaroles, are monitored using an infra-red camera device permanently installed on the caldera rim.This thermal dataset constitutes the first opportunity to understand the structure and dynamics of the hydrothermal system and its ability to relay deep-seated heat and mass perturbations. We present in this communication an overview of this thermal datasets focusing on ground/fumaroles temperature evolution during volcanic crisis and rest periods and analyzing correlations with the other permanently acquired data such as the temporal evolution of gas geochemistry (CO2, SO2, H2S), ground deformation and micro-seismic activity. We finally propose a conceptual model of fluid flow architecture within the edifice which paves the way for future quantitative models of hydrothermal heat and mass transfers.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24592299','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24592299"><span>Massage therapy and canadians' health care needs 2020: proceedings of a national research priority setting summit.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dryden, Trish; Sumpton, Bryn; Shipwright, Stacey; Kahn, Janet; Reece, Barbara Findlay</p> <p>2014-03-01</p> <p>The health care landscape in Canada is changing rapidly as forces, such as an aging population, increasingly complex health issues and treatments, and economic pressure to reduce health care costs, bear down on the system. A cohesive national research agenda for massage therapy (MT) is needed in order to ensure maximum benefit is derived from research on treatment, health care policy, and cost effectiveness. A one-day invitational summit was held in Toronto, Ontario to build strategic alliances among Canadian and international researchers, policy makers, and other stakeholders to help shape a national research agenda for MT. Using a modified Delphi method, the summit organizers conducted two pre-summit surveys to ensure that time spent during the summit was relevant and productive. The summit was facilitated using the principles of Appreciative Inquiry which included a "4D" strategic planning approach (defining, discovery, dreaming, designing) and application of a SOAR framework (strengths, opportunities, aspirations, and results). Twenty-six researchers, policymakers, and other stakeholders actively participated in the events. Priority topics that massage therapists believe are important to the Canadian public, other health care providers, and policy makers and massage therapists themselves were identified. A framework for a national massage therapy (MT) research agenda, a grand vision of the future for MT research, and a 12-month action plan were developed. The summit provided an excellent opportunity for key stakeholders to come together and use their experience and knowledge of MT to develop a much-needed plan for moving the MT research and professionalization agenda forward.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3934855','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3934855"><span>Massage Therapy and Canadians’ Health Care Needs 2020: Proceedings of a National Research Priority Setting Summit</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Dryden, Trish; Sumpton, Bryn; Shipwright, Stacey; Kahn, Janet; Reece, Barbara (Findlay)</p> <p>2014-01-01</p> <p>Background The health care landscape in Canada is changing rapidly as forces, such as an aging population, increasingly complex health issues and treatments, and economic pressure to reduce health care costs, bear down on the system. A cohesive national research agenda for massage therapy (MT) is needed in order to ensure maximum benefit is derived from research on treatment, health care policy, and cost effectiveness. Setting A one-day invitational summit was held in Toronto, Ontario to build strategic alliances among Canadian and international researchers, policy makers, and other stakeholders to help shape a national research agenda for MT. Method Using a modified Delphi method, the summit organizers conducted two pre-summit surveys to ensure that time spent during the summit was relevant and productive. The summit was facilitated using the principles of Appreciative Inquiry which included a “4D” strategic planning approach (defining, discovery, dreaming, designing) and application of a SOAR framework (strengths, opportunities, aspirations, and results). Participants Twenty-six researchers, policymakers, and other stakeholders actively participated in the events. Results Priority topics that massage therapists believe are important to the Canadian public, other health care providers, and policy makers and massage therapists themselves were identified. A framework for a national massage therapy (MT) research agenda, a grand vision of the future for MT research, and a 12-month action plan were developed. Conclusion The summit provided an excellent opportunity for key stakeholders to come together and use their experience and knowledge of MT to develop a much-needed plan for moving the MT research and professionalization agenda forward. PMID:24592299</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=GL-2002-001363&hterms=Volcano+Facts&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DVolcano%2BFacts','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=GL-2002-001363&hterms=Volcano+Facts&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DVolcano%2BFacts"><span>Summit Crater of Mauna Loa</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2002-01-01</p> <p>Astronauts obtained this detailed image of the summit caldera of Mauna Loa volcano, called Mokuaweoweo Caldera. Mauna Loa is the largest volcano on our planet-the summit elevation is 4,170 m (over 13,600 ft), but the volcano's summit rises 9 km above the sea floor. The sharp features of the summit caldera and lava flows that drain outward from the summit are tribute to the fact that Mauna Loa is one of the Earth's most active volcanoes. The most recent eruption was in 1984. The straight line the cuts through the center of the crater from top to bottom is a rift zone-an area that pulls apart as magma reaches the surface. A weather observatory run by NOAA's Climate Monitoring and Diagnostics Lab is on the volcano's north slope at 11,000 ft (3397 m). This facility, known as the Mauna Loa Observatory, is the site where scientists have documented the constantly increasing concentrations of global atmospheric carbon dioxide. Other resources about Mauna Loa: http://wwwhvo.wr.usgs.gov/maunaloa/ http://www.cmdl.noaa.gov/obop/mlo/ http://www.volcano.si.edu/gvp/usgs/vol_archive/maunaloa.htm Astronaut photograph ISS005-E-7002 was provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17772421','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17772421"><span>Helium/Carbon dioxide ratios as premonitors of volcanic activity.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Thomas, D M; Naughton, J J</p> <p>1979-06-15</p> <p>The composition of the gaseous emissions of two fumaroles at the summit of Kilauea Volcano was monitored for môre than 2 years. Magma was released from the summit reservoir on three occasions during this period; prior to or during each event the ratios of helium to carbon dioxide in the fumarole gases decreased substantially from that observed during periods of quiescence.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70024289','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70024289"><span>Subsidence at Kiska volcano, Western Aleutians, detected by satellite radar interferometry</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lu, Z.; Masterlark, Timothy; Power, J.; Dzurisin, D.; Wicks, Charles</p> <p>2002-01-01</p> <p>Sequential interferometric synthetic aperture radar images of Kiska, the westernmost historically active volcano in the Aleutian arc, show that a circular area about 3 km in diameter centered near the summit subsided by as much as 10 cm from 1995 to 2001, mostly during 1999 and 2000. An elastic Mogi-type deformation model suggests that the source is within 1 km of the surface. Based on the shallow source depth, the copious amounts of steam during recent eruptions, and recent field reports of vigorous steaming and persistent ground shaking near the summit area, we attribute the subsidence to decreased pore-fluid pressure within a shallow hydrothermal system beneath the summit area.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.V53A1131S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.V53A1131S"><span>The Fathers Day Eruption of Kilauea, Volcano, Hawaii: a gas Emissions Perspective</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sutton, A.; Elias, T.</p> <p>2007-12-01</p> <p>Gas release events from Kilauea's summit magma reservoir and East Rift Zone (ERZ) before and during the June 17, 2007 Fathers Day eruptive sequence provide evidence of correlated summit and rift processes and illustrate how perturbations in magma supply from depth can disrupt steady processes at the surface. Changes in summit CO2 emission rates are thought to reflect changes in deep magma supply and the movement of magma into the rift zone. During the several years preceding the Fathers Day activity, Kilauea had undergone a surge of magma supply and effusive output, as evidenced by gas release and cross-caldera extension. In 2004, the CO2 emission rate, which had been quasi-steady, below 10,000 tonnes/day for the preceeding eight years, began to increase. By mid-2004 the rate had doubled, and by 2005, had tripled, reaching nearly 30,000 t/d. The peak and subsequent decline in summit CO2 attended a similar pattern in east rift SO2 emissions, which are used at Kilauea as one proxy for effusion rate. The surge in magma supply and lava effusion rate may have unsettled Kilauea's plumbing enough to set the stage for the subsequent Fathers Day intrusive and eruptive activity. As magma was withdrawn from the summit reservoir on 17 June 2007, forming the dike that intruded the Upper East Rift Zone, overburden pressure in the reservoir decreased allowing dissolved gases to exsolve and escape from the melt. The more soluble SO2, would be more affected by this pressure change than CO2, which exsolves at much greater depth. Summit SO2 emissions increased nearly four-fold as the summit deflated and summit and Upper East Rift tremor spiked. Increased ambient gas concentrations downwind of Halema`uma`u Crater resulted from the sharp increase in SO2 emission rates and caused the national park to close Crater Rim Drive in this area for several days. The Fathers Day intrusion, subsequent collapses at Pu`u `O`o, and the brief eruption at Kane Nui O Hamo (KNH) profoundly changed ERZ gases as well. SO2 emissions declined dramatically from Pu`u `O`o, dropping below 100 t/d by early July and remained low for several weeks even after lava reappeared in Pu`u `O`o. This overall decline in east rift gas release is reasonably consistent with the observed eruptive events: the dike likely robbed the magma supply but produced only the scanty KNH eruption, and the thinness of the dike geometry proved a poor conduit for SO2 release from depth. The beginning of the 21 July fissure activity reflected a return of magma and significant gas release to the Pu`u `O`o area as pressure within the shallow vent system exceeded structural integrity of the edifice. Following a brief increase in SO2 emissions at the onset of fissure activity, values declined, while effusion remained high. The low level of SO2 release, which persisted for the first several weeks of this fissure activity possibly reflected displacement of old rift-stored magma with newer magma coming from the summit and passing beneath the Pu`u `O`o system. Beginning 12 August, Pu`u `O`o re-emerged as Kilauea's primary SO2 degassing source, even though all extrusion as of this writing is occurring from the fissure system east of the cone. Currently, Kilauea appears to be following a pattern similar to that of the 1986-1991 Kupaianaha era, wherein most SO2 release was from Pu`u `O`o while active extrusion occurred down rift.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss033e018010.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss033e018010.html"><span>Earth Observation taken by the Expedition 33 crew</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-11-03</p> <p>ISS033-E-018010 (3 Nov. 2012) --- Volcanoes in central Kamchatka are featured in this image photographed by an Expedition 33 crew member on the International Space Station. The snow-covered peaks of several volcanoes of the central Kamchatka Peninsula are visible standing above a fairly uniform cloud deck that obscures the surrounding lowlands. In addition to the rippled cloud patterns caused by interactions of air currents and the volcanoes, a steam and ash plume is visible at center extending north-northeast from the relatively low summit (2,882 meters above sea level) of Bezymianny volcano. Volcanic activity in this part of Russia is relatively frequent, and well monitored by Russia’s Kamchatka Volcanic Eruption Response Team (KVERT). The KVERT website provides updated information about the activity levels on the peninsula, including aviation alerts and webcams. Directly to the north and northeast of Bezymianny, the much larger and taller stratovolcanoes Kamen (4,585 meters above sea level) and Kliuchevskoi (4,835 meters above sea level) are visible. Kliuchevskoi, Kamchatka’s most active volcano, last erupted in 2011 whereas neighboring Kamen has not erupted during the recorded history of the region. An explosive eruption from the summit of the large volcanic massif of Ushkovsky (3,943 meters above sea level; left) northwest of Bezymianny occurred in 1890; this is the most recent activity at this volcano. To the south of Bezymianny, the peaks of Zimina (3,081 meters above sea level) and Udina (2,923 meters above sea level) volcanoes are just visible above the cloud deck; no historical eruptions are known from either volcanic center. While the large Tobalchik volcano to the southwest (bottom center) is largely formed from a basaltic shield volcano, its highest peak (3,682 meters above sea level) is formed from an older stratovolcano. Tobalchik last erupted in 1976. While this image may look like it was taken from the normal altitude of a passenger jet, the space station was located approximately 417 kilometers above the southeastern Sea of Okhotsk; projected downwards to Earth’s surface, the space station was located over 700 kilometers to the southwest of the volcanoes in the image. The combination of low viewing angle from the orbital outpost, shadows, and height and distance from the volcanoes contributes to the appearance of topographic relief visible in the image.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.V21C2347S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.V21C2347S"><span>Satellite thermal and tilt measurements of the 2007 - 2008 eruptive period at Kilauea volcano: Implications for down rift magma transport</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Steffke, A. M.; Harris, A. J.</p> <p>2010-12-01</p> <p>The 2007-2008 eruptive period at Kilauea volcano, Hawai‘i, was characterized by frequent changes in style, location and intensity of effusive activity. We use thermal data from the GOES-Imager and MODIS to investigate three particularly interesting eruptive periods: (1) June 17 - July 4, 2007 (the Father’s Day eruption), (2) July 21 - August 5, 2007, and (3) August 6 - 11, 2008. Each of these eruptive periods were accompanied by deflation-inflation events (DI events) at the summit of Kilauea, with a delayed increase in activity at Pu `u `O`o, indicating the arrival of new magma at the eruption sites, some 20 km distant from the summit, following each DI event. Arrival of new magma, and the associated increase in effusive activity, is apparent in the satellite data as an increase in the thermal intensity of the recorded hot spot. This allows us to time the arrival of new magma (or its pressure pulse) down the rift zone that connects the summit and the eruption site over a time scale of hours, or in the case of GOES data - 15 minutes. We can compare the satellite-derived thermal intensity time series with the deflation and inflation events occurring at the summit to determine transit times for the response down rift. Using both the satellite and tilt measurements, the volumes of magma entering and exiting the system can also be compared, with the satellite data giving the volume subsequently erupted down rift at Pu`u `O`o and across the active lava flow field.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/7208496-three-dimensional-crust-mantle-structure-kilauea-volcano-hawaii','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/7208496-three-dimensional-crust-mantle-structure-kilauea-volcano-hawaii"><span>Three-dimensional crust and mantle structure of Kilauea Volcano, Hawaii</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Ellsworth, W.L.; Koyanagi, R.Y.</p> <p>1977-11-10</p> <p>Teleseismic P wave arrival times recorded by a dense network of seismograph stations located on Kilauea volcano, Hawaii, are inverted to determine lateral variation in crust and upper mantle structure to a depth of 70 km. The crustal structure is dominated by relatively high velocities within the central summit complex and along the two radial rift zones compared with the nonrift flank of the volcano. Both the mean crustal velocity contrast between summit and nonrift flank and the distribution of velocities agree well with results from crustal refraction studies. Comparison of the velocity structure with Bouguer gravity anomalies over themore » volcano through a simple physical model also gives excellent agreement. Mantle structure appears to be more homogeneous than crustal structure. The root mean square velocity variation for the mantle averages only 1.5%, whereas variation within the crust exceeds 4%. The summit of Kilauea is underlain by normal velocity (8.1 km/s) material within the uppermost mantle (12--25 km), suggesting that large magma storage reservoirs are not present at this level and that the passageways from deeper sources must be quite narrow. No evidence is found for substantial volumes of partially molten rock (5%) within the mantle to depths of at least 40 km. Below about 30 km, low-velocity zones (1--2%) underlie the summits of Kilauea and nearby Mauna Loa and extend south of Kilauea into a broad offshore zone. Correlation of volcanic tremor source locations and persistent zones of mantle earthquakes with low-velocity mantle between 27.5- and 42.5-km depth suggests that a laterally extensive conduit system feeds magma to the volcanic summits from sources either at comparable depth or deeper within the mantle. The center of contemporary magmatic production and/or upwelling from deeper in the mantle appears to extend well to the south of the active volcanic summits, suggesting that the Hawaiian Island chain is actively extending to the southeast.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.V23E0515C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.V23E0515C"><span>b-value distribution in and around Mt. Tarumae, Japan</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chiba, K.</p> <p>2017-12-01</p> <p>Mt. Tarumae is an active volcano located in southeastern Shikotsu caldera, Hokkaido, Japan. Recently, crustal expansion occurred in 1999-2000 and 2013 near the summit of Mt. Tarumae, with a M5.6 earthquake recorded west of the summit on 8 July 2014. In this study, I determined hypocenter distributions and then performed b-value analysis for the period between 1 August 2014 and 12 August 2016 to improve our understanding of the magma system geometry beneath the summit of Mt. Tarumae. Hypocenters are mainly distributed in two regions: 3 - 5 km west of Mt. Tarumae, and beneath the volcano. I then determined b-value distributions. Regions with relatively high b-values ( 1.3) are located at depths of -0.5 to 2.0 km beneath the summit and at depths greater than 6.0 km in the northwestern part at about 1.5 - 3.0 km from the summit, while a region with relatively low b-values ( 0.6) is located at depths of 2.0 - 6.0 km beneath the summit. Compared the b-value distributions with other geophysical observations, it was found that the high b-value region from -0.5 to 2.0 km depth corresponds to regions of lower resistivity, positive self-potential anomaly, and an inflation source observed in 1999-2000. It is thus inferred that this region is generated by crustal heterogeneity, a decrease in effective normal stress, and change of a frictional property due to the development of faults and fissures, and the circulation of hydrothermal fluids. On the other hand, the inflation source observed in 2013 was located near the boundary between the low b-value region beneath the summit and the deeper high b-value region in the northwestern part at about 1.5 - 3.0 km from the summit. Studies of other volcanoes suggest that such a high-b-value region likely corresponds to a magma chamber. From the deeper high b-value region estimated in this study, I am able to point out that the magma chamber is located to depths greater than 6.0 km in the northwestern part at about 1.5 - 3.0 km from the summit. Thus, these findings contribute to our understanding of the magma plumbing system beneath the summit of Mt. Tarumae.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/pp/1801/downloads/pp1801_Chap6_Helz.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/pp/1801/downloads/pp1801_Chap6_Helz.pdf"><span>Petrologic insights into basaltic volcanism at historically active Hawaiian volcanoes: Chapter 6 in Characteristics of Hawaiian volcanoes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Helz, Rosalind L.; Clague, David A.; Sisson, Thomas W.; Thornber, Carl R.; Poland, Michael P.; Takahashi, T. Jane; Landowski, Claire M.</p> <p>2014-01-01</p> <p>Contributions to our knowledge of the nature of the mantle source(s) of Hawaiian basalts are reviewed briefly, although this is a topic where debate is ongoing. Finally, our accumulated petrologic observations impose constraints on the nature of the summit reservoirs at Kīlauea and Mauna Loa, specifically whether the summit chamber has been continuous or segmented during past decades.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.V12A..06H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.V12A..06H"><span>Ground Tilt Time Delays between Kilauea Volcano's Summit and East Rift Zone Caused by Magma Reservoir Buffering</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Haney, M. M.; Patrick, M. R.; Anderson, K. R.</p> <p>2016-12-01</p> <p>A cyclic pattern of ground deformation, called a deflation-inflation (DI) cycle, is commonly observed at Kilauea Volcano, Hawai`i. These cycles are an important part of Kilauea's eruptive activity because they directly influence the level of the summit lava lake as well as the effusion rate (and resulting lava flow hazard) at the East Rift Zone eruption site at Pu`u `O`o. DI events normally span several days, and are measured both at the summit and at Pu`u `O`o cone (20 km distance). Signals appear first at the summit and are then observed at Pu`u `O`o after an apparent delay of between 0.5 and 10 hours, which has been previously interpreted as reflecting magma transport time. We propose an alternate explanation, in which the apparent delay is an artifact of buffering by the small magma reservoir thought to exist at Pu`u `O`o. Simple Poiseuille flow modeling demonstrates that this apparent delay can be reproduced by the changing balance of inflow (from the summit) and outflow (to surface lava flows) at the Pu`u `O`o magma reservoir. The apparent delay is sensitive to the geometry of the conduit leaving Pu`u `O`o, feeding surface lava flows. We demonstrate how the reservoir buffering is quantitatively equivalent to a causal low-pass filter, which explains both the apparent delay as well as the smoothed, skewed nature of the signal at Pu`u `O`o relative to the summit. By comparing summit and Pu`u `O`o ground tilt signals over an extended time period, it may be possible to constrain the changing geometry of the shallow magmatic system through time.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://ngmdb.usgs.gov/Prodesc/proddesc_68315.htm','USGSPUBS'); return false;" href="http://ngmdb.usgs.gov/Prodesc/proddesc_68315.htm"><span>Geologic Map of the Summit Region of Kilauea Volcano, Hawaii</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Neal, Christina A.; Lockwood, John P.</p> <p>2003-01-01</p> <p>This report consists of a large map sheet and a pamphlet. The map shows the geology, some photographs, description of map units, and correlation of map units. The pamphlet gives the full text about the geologic map. The area covered by this map includes parts of four U.S. Geological Survey 7.5' topographic quadrangles (Kilauea Crater, Volcano, Ka`u Desert, and Makaopuhi). It encompasses the summit, upper rift zones, and Koa`e Fault System of Kilauea Volcano and a part of the adjacent, southeast flank of Mauna Loa Volcano. The map is dominated by products of eruptions from Kilauea Volcano, the southernmost of the five volcanoes on the Island of Hawai`i and one of the world's most active volcanoes. At its summit (1,243 m) is Kilauea Crater, a 3 km-by-5 km collapse caldera that formed, possibly over several centuries, between about 200 and 500 years ago. Radiating away from the summit caldera are two linear zones of intrusion and eruption, the east and the southwest rift zones. Repeated subaerial eruptions from the summit and rift zones have built a gently sloping, elongate shield volcano covering approximately 1,500 km2. Much of the volcano lies under water; the east rift zone extends 110 km from the summit to a depth of more than 5,000 m below sea level; whereas the southwest rift zone has a more limited submarine continuation. South of the summit caldera, mostly north-facing normal faults and open fractures of the Koa`e Fault System extend between the two rift zones. The Koa`e Fault System is interpreted as a tear-away structure that accommodates southward movement of Kilauea's flank in response to distension of the volcano perpendicular to the rift zones.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017NatCC...7..783B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017NatCC...7..783B"><span>The appeasement effect of a United Nations climate summit on the German public</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brüggemann, Michael; de Silva-Schmidt, Fenja; Hoppe, Imke; Arlt, Dorothee; Schmitt, Josephine B.</p> <p>2017-11-01</p> <p>The annual UN climate summits receive intense global media coverage, and as such could engage local publics around the world, stimulate debate and knowledge about climate politics, and, ultimately, mobilize people to combat climate change. Here we show that, in contrast to these hopes, although the German public were exposed to news about the 2015 Paris summit, they did not engage with it in a more active way. Comparing knowledge and attitudes before, during and after the summit using a three-wave online panel survey (quota sample, N = 1,121), we find that respondents learnt a few basic facts about the conference but they continue to lack basic background knowledge about climate policy. Trust in global climate policy increased a little, but citizens were less inclined to support a leading role for Germany in climate politics. Moreover, they were not more likely to engage personally in climate protection. These results suggest that this global media event had a modest appeasing rather than mobilizing effect.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1989BVol...51...51H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1989BVol...51...51H"><span>A facies model for a quaternary andesitic composite volcano: Ruapehu, New Zealand</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hackett, W. R.; Houghton, B. F.</p> <p>1989-01-01</p> <p>Ruapehu composite volcano is a dynamic volcanic-sedimentary system, characterised by high accumulation rates and by rapid lateral and vertical change in facies. Four major cone-building episodes have occurred over 250 Ka, from a variety of summit, flank and satellite vents. Eruptive styles include subplinian, strombolian, phreatomagmatic, vulcanian and dome-related explosive eruptions, and extrusion of lava flows and domes. The volcano can be divided into two parts: a composite cone of volume 110 km3, surrounded by an equally voluminous ring plain. Complementary portions of Ruapehu's history are preserved in cone-forming and ring plain environments. Cone-forming sequences are dominated by sheet- and autobrecciated-lava flows, which seldom reach the ring plain. The ring plain is built predominantly from the products of explosive volcanism, both the distal primary pyroclastic deposits and the reworked material eroded from the cone. Much of the material entering the ring plain is transported by lahars either generated directly by eruptions or triggered by the high intensity rain storms which characterise the region. Ring plain detritus is reworked rapidly by concentrated and hyperconcentrated streams in pulses of rapid aggradation immediately following eruptions and more gradually in the longer intervals between eruptions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.T13B2193W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.T13B2193W"><span>Transport of Fine Ash Through the Water Column at Erupting Volcanoes - Monowai Cone, Kermadec-Tonga Arc</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Walker, S. L.; Baker, E. T.; Leybourne, M. I.; de Ronde, C. E.; Greene, R.; Faure, K.; Chadwick, W.; Dziak, R. P.; Lupton, J. E.; Lebon, G.</p> <p>2010-12-01</p> <p>Monowai cone is a large, active, basaltic stratovolcano, part of the submarine Monowai volcanic center (MVC) located at ~26°S on the Kermadec-Tonga arc. At other actively erupting submarine volcanoes, magma extrusions and hydrothermal vents have been located only near the summit of the edifice, generating plumes enriched with hydrothermal components and magmatic gasses that disperse into the ocean environment at, or shallower than, the summit depth. Plumes found deeper than summit depths are dominated by fresh volcaniclastic ash particles, devoid of hydrothermal tracers, emplaced episodically by down-slope gravity flows, and transport fine ash to 10’s of km from the active eruptions. A water column survey of the MVC in 2004 mapped intensely hydrothermal-magmatic plumes over the shallow (~130 m) summit of Monowai cone and widespread plumes around its flanks. Due to the more complex multiple parasitic cone and caldera structure of MVC, we analyzed the dissolved and particulate components of the flank plumes for evidence of additional sources. Although hydrothermal plumes exist within the adjacent caldera, none of the parasitic cones on Monowai cone or elsewhere within the MVC were hydrothermally or volcanically active. The combination of an intensely enriched summit plume, sulfur particles and bubbles at the sea surface, and ash-dominated flank plumes indicate Monowai cone was actively erupting at the time of the 2004 survey. Monowai cone is thus the fourth erupting submarine volcano we have encountered, and all have had deep ash plumes distributed around their flanks [the others are: Kavachi (Solomon Island arc), NW Rota-1 (Mariana arc) and W Mata (NE Lau basin)]. These deep ash plumes are a syneruptive phenomenon, but it is unknown how they are related to eruptive style and output, or to the cycles of construction and collapse that occur on the slopes of submarine volcanoes. Repeat multibeam bathymetric surveys have documented two large-scale sector collapse events at Monowai and one at NW Rota-1, as well as constructional deposits extending down the flanks of these volcanoes. Acoustic records at Monowai and NW Rota-1 suggest sector collapse events are infrequent while eruptions, and the resulting supply of depositional material, have been nearly continuous. The sector collapse events occurred at times remote from our plume surveys, so, large landslide events are not a prerequisite for the presence of deep ash plumes. Despite a wide range of summit depths (<10 m at Kavachi to 1500 m at W Mata), lava types (basaltic-andesite, boninite, and basalt), and eruptive styles (Surtseyan, Strombolian, and effusive flows with active pillow formation), the deep particle plumes at each of these volcanoes are remarkably similar in their widespread distribution (to 10’s of km from the summit and at multiple depths down the flanks) and composition (dominantly fresh volcanic ash). Moderate eruption rates, lava-seawater interaction and steep slopes below an eruptive vent may be sufficient to initiate the transport of fine ash into the ocean environment and distal sediments via these types of plumes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-s39-75-101.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-s39-75-101.html"><span>Colima Volcano, State of Jalisco, Mexico</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>1991-05-06</p> <p>STS039-75-101 (28 April-6 May 1991) --- Spending over eight days in Earth orbit, the STS-39 crew was able to return with photographic coverage of highly variegated geographic scenery, including a number of volcanoes such as Mexico's Colima. Located south of Guadalajara, Colima is Mexico's most active volcano. The current activity started in the first part of March 1991 with avalanches occurring, followed by lava extrusion and ash emission. Colima is captured here in action. The steam plume drifts eastward from the 13,325 ft. summit. Scars from recent landslides can be seen on the southwest flank of the summit.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUSM...V42A08L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUSM...V42A08L"><span>Martian Rootless Cones as Indicators of Recent Deposits of Shallow Equatorial Ground Ice</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lanagan, P. D.; McEwen, A. S.; Keszthelyi, L. P.; Thordarson, T.</p> <p>2001-05-01</p> <p>Small, cratered cones have been identified in high-resolution Mars Orbiter Camera images of the Cerberus Plains and Amazonis Planitia, Mars [1].These cones occur in small clusters independent of obvious fissures, are superimposed on fresh lava flows, and do not appear to issue lavas themselves. Observed cones have basal diameters <250m and large summit craters. The structures are similar in both morphology and dimensions to the larger of Icelandic rootless cones,or pseudocraters [2], which form due to phreatomagmatic explosions caused by mechanical mixtures of tube-fed lavas with near-surface water-saturated substrates[3]. If the martian cones form in a similar manner as terrestrial rootless cones,then they may provide constraints on the spatial and temporal distribution of martian ground ice. Lavas associated with the western Amazonis cone fields(24N, 171W) show well-preserved surface morphologies and few superimposed impact craters. Impact crater statistics indicate that these lavas and superimposed cones may have been emplaced less than 10 Ma, indicating near-surface ice must have been present at the time. The presence of young rootless cones helps constrain the origins of ground ice. Relic ground ice is unlikely to be a volatile source for rootless eruptions as regolith in equatorial regions is likely to be desiccated to a depth of 200-m [4]. Vapor exchange between the regolith and atmosphere due to obliquity variations [5] may input enough water into the subsurface to reproduce martian cones of observed diameters calculated by explosion models[6]. However, surficial waters released in outflow events may be required to recharge requisite quantities of ground ice. Most proposed rootless cone fields appear in or close to fluvial features of the Cerberus Plains and Marte Valles[7]. Nested summit craters of some cones indicate a multi-stage constructional process, which would require recharge of aquifers beneath the erupting cones. Such a process would require the substrate to be permeable and contain enough ground ice to allow water to flow to the explosion point. [1]Lanagan, P. D. et al.(2001)Geophys Res Let, submitted. [2]Thorarinsson, S.(1953)Bull Vol, 14, 3-44. [3]Thordarson, T.(2000)Volcano-Ice Interactions on Earth and Mars, 36. [4]Clifford, S. M., and Hillel, D.(1983)J Geophys Res, 88, 2456-2474. [5]Mellon, M. T., and B. M. Jakosky.(1995)J Geophys Res, 100, 11781-11799. [6]Fagents, S. A. and R. Greeley.(2000)Volcano-Ice Interactions on Earth and Mars, 13. [7]Burr, D. M. et al.(2001)Geophys Res Abs.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JVGR..198...19R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JVGR..198...19R"><span>Characteristics and management of the 2006-2008 volcanic crisis at the Ubinas volcano (Peru)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rivera, Marco; Thouret, Jean-Claude; Mariño, Jersy; Berolatti, Rossemary; Fuentes, José</p> <p>2010-12-01</p> <p>Ubinas volcano is located 75 km East of Arequipa and ca. 5000 people are living within 12 km from the summit. This composite cone is considered the most active volcano in southern Peru owing to its 24 low to moderate magnitude (VEI 1-3) eruptions in the past 500 years. The onset of the most recent eruptive episode occurred on 27 March 2006, following 8 months of heightened fumarolic activity. Vulcanian explosions occurred between 14 April 2006 and September 2007, at a time ejecting blocks up to 40 cm in diameter to distances of 2 km. Ash columns commonly rose to 3.5 km above the caldera rim and dispersed fine ash and aerosols to distances of 80 km between April 2006 and April 2007. Until April 2007, the total volume of ash was estimated at 0.004 km 3, suggesting that the volume of fresh magma was small. Ash fallout has affected residents, livestock, water supplies, and crop cultivation within an area of ca. 100 km 2 around the volcano. Continuous degassing and intermittent mild vulcanian explosions lasted until the end of 2008. Shortly after the initial explosions on mid April 2006 that spread ash fallout within 7 km of the volcano, an integrated Scientific Committee including three Peruvian institutes affiliated to the Regional Committee of Civil Defense for Moquegua, aided by members of the international cooperation, worked together to: i) elaborate and publish volcanic hazard maps; ii) inform and educate the population; and iii) advise regional authorities in regard to the management of the volcanic crisis and the preparation of contingency plans. Although the 2006-2008 volcanic crisis has been moderate, its management has been a difficult task even though less than 5000 people now live around the Ubinas volcano. However, the successful management has provided experience and skills to the scientific community. This volcanic crisis was not the first one that Peru has experienced but the 2006-2008 experience is the first long-lasting crisis that the Peruvian civil authorities have had to cope with, including attempts to utilize a new alert-level scheme and communications system, and the successful evacuation of 1150 people. Lessons learned can be applied to future volcanic crises in southern Peru, particularly in the case of reawakening of El Misti volcano nearby Arequipa.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70027989','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70027989"><span>Seismic signature of a phreatic explosion: Hydrofracturing damage at Karthala volcano, Grande Comore Island, Indian Ocean</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Savin, C.; Grasso, J.-R.; Bachelery, P.</p> <p>2005-01-01</p> <p>Karthala volcano is a basaltic shield volcano with an active hydrothermal system that forms the southern two-thirds of the Grande Comore Island, off the east coat of Africa, northwest of Madagascar. Since the start of volcano monitoring by the local volcano observatory in 1988, the July 11th, 1991 phreatic eruption was the first volcanic event seismically recorded on this volcano, and a rare example of a monitored basaltic shield. From 1991 to 1995 the VT locations, 0.5<Ml<4.3, show a crack shaped pattern (3 km long, 1 km wide) within the summit caldera extending at depth from -2 km to +2 km relative to sea level. This N-S elongated pattern coincides with the direction of the regional maximum horizontal stress as deduced from regional focal mechanism solutions. This brittle signature of the damage associated with the 1991 phreatic eruption is a typical pattern of the seismicity induced by controlled fluid injections such as those applied at geothermal fields, in oil and gas recovery, or for stress measurements. It suggests the 1991 phreatic eruption was driven by hydraulic fracturing induced by forced fluid flow. We propose that the extremely high LP and VT seismicity rates, relative to other effusive volcanoes, during the climax of the 1991 phreatic explosion, are due to the activation of the whole hydrothermal system, as roughly sized by the distribution of VT hypocenters. The seismicity rate in 1995 was still higher than the pre-eruption seismicity rate, and disagrees with the time pattern of thermo-elastic stress readjustment induced by single magma intrusions at basaltic volcanoes. We propose that it corresponds to the still ongoing relaxation of pressure heterogeneity within the hydrothermal system as suggested by the few LP events that still occurred in 1995. ?? Springer-Verlag 2005.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JVGR..340..170L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JVGR..340..170L"><span>Evidences of volcanic unrest on high-temperature fumaroles by satellite thermal monitoring: The case of Santa Ana volcano, El Salvador</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Laiolo, M.; Coppola, D.; Barahona, F.; Benítez, J. E.; Cigolini, C.; Escobar, D.; Funes, R.; Gutierrez, E.; Henriquez, B.; Hernandez, A.; Montalvo, F.; Olmos, R.; Ripepe, M.; Finizola, A.</p> <p>2017-06-01</p> <p>On October 1st, 2005, Santa Ana volcano (El Salvador) underwent a VEI 3 phreatomagmatic eruption after approximately one century of rest. Casualties and damages to some of the local infrastructures and surrounding plantations were followed by the evacuation of the nearby communities. The analysis of MODIS (Moderate Resolution Imaging Spectroradiometer) infrared data reveals that the main explosion was preceded by a one-year-long thermal unrest, associated to the development of a fumaroles field, located at the western rim of the summit crater lake. By combining space-based thermal flux and ground-based measurements (seismicity, sulfur emissions and lake temperatures), we suggest that the activity observed at Santa Ana between 2004 and 2005 was driven by the gradual intrusion of an undegassed magma body at a very shallow depth. Magma injection induced thermal anomalies associated with sustained degassing from the fumaroles field and promoted the interaction between the magmatic-hydrothermal system and the overlying water table. This process culminated into the VEI 3 phreatomagmatic eruption of October 2005 that strongly modified the shallow structure of the crater area. The subsequent three-years-long activity resulted from self-sealing of the fracture system and by the opening of a new fracture network directly connecting the deeper hydrothermal system with the crater lake. Our results show that satellite-based thermal data allow us to detect the expansion of the high-temperature fumarolic field. This may precede an explosive eruption and/or a lava dome extrusion. In particular, we show that thermal records can be analyzed with other geochemical (i.e. SO2 emissions) and geophysical (seismicity) data to track a shallow magmatic intrusion interacting with the surrounding hydrothermal system. This provides a remarkable support for volcano monitoring and eruption forecasting, particularly in remote areas where permanent ground data acquisition is hazardous, expensive and difficult.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMNH31C..03W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMNH31C..03W"><span>On the use of UAVs at active volcanoes: a case study from Volcan de Fuego, Guatemala</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Watson, M.; Chigna, G.; Wood, K.; Richardson, T.; Liu, E.; Schellenberg, B.; Thomas, H.; Naismith, A.</p> <p>2017-12-01</p> <p>Volcan de Fuego, Guatemala, is one of Central America's most active systems. More than one hundred thousand people live within ten kilometres of the summit, many of them in profound poverty. Both the summit region and the volcano's steep sided valleys present significant access challenges, mostly associated with unacceptably high risk. Unmanned aerial vehicles (UAVs) offer the opportunity to observe, map and quantify emissions of tephra, gas, lava and heat flux and, using structure from motion algorithms, model dynamic topography. During recent campaigns, the team have completed observations of changes in the summit morphology immediately prior a paroxysmal eruption, mapped the key drainage systems after the fifth of May 2017 eruption and sampled the plume for tephra and gases using a range of onboard instruments. I will present the group's findings within a broader context of hazard mitigation and physical volcanology, and discuss the future of UAVs in volcano monitoring and research.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70155874','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70155874"><span>Episodic deflation-inflation events at Kīlauea Volcano and implications for the shallow magma system: Chapter 11</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Anderson, Kyle R.; Poland, Michael; Johnson, Jessica H.; Miklius, Asta; Carey, Rebecca; Cayol, Valérie; Poland, Michael P.; Weis, Dominique</p> <p>2015-01-01</p> <p>Episodic variations in magma pressures and flow rates at Kīlauea Volcano, defined by a characteristic temporal evolution and termed deflation-inflation (DI) events, have been observed since at least the 1990s. DI events consist of transient, days-long deflations and subsequent reinflations of the summit region, accompanied since 2008 by fluctuations in the surface height of Kīlauea's summit lava lake. After a delay of minutes to hours, these events also often appear along the volcano's East Rift Zone in ground deformation data and as temporary reductions in eruption rate (sometimes followed by brief surges). Notable pauses in DI activity have preceded many eruptive events at Kīlauea. We analyzed more than 500 DI events recorded by borehole tiltmeters at the summit during 2000–2013. Inverse modeling suggests that DI-related ground deformation at the summit is generated by pressure transients in a shallow magma reservoir located beneath the east margin of Halema‘uma‘u Crater and that this reservoir has remained remarkably stable for more than a decade. Utilizing tilt data and variation in the level of the summit lava lake during a large DI event, we estimate a reservoir volume of approximately 1 km3 (0.2–5.5 km3 at 95% confidence).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED521230.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED521230.pdf"><span>Summiteers--Moving Mountains with Bereaved Boys</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Renner, Hans-Georg</p> <p>2011-01-01</p> <p>Summiteers are people who rush to the top. There is a mountain summit and a metaphorical summit inside us which we can climb. In the area of mountain summits, Reinhold Messner is surely the best known and most successful summiteer. He climbed, among other things, the highest peak on earth without supplemental oxygen. In the language of the country…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA03371.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA03371.html"><span>Perspective View, Mt. Etna, Italy</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2002-11-01</p> <p>Italy's Mount Etna is the focus of this perspective view made from an Advanced Spaceborne Thermal and Emission Radiometer (ASTER) image from NASA's Terra spacecraft overlaid on Shuttle Radar Topography Mission (SRTM) topography. The image is looking south with dark lava flows from the 1600's (center) to 1981 (long flow at lower right) visible in the foreground and the summit of Etna above. The city of Catania is barely visible behind Etna on the bay at the upper left. In late October 2002, Etna erupted again, sending lava flows down the north and south sides of the volcano. The north flows are near the center of this view, but the ASTER image is from before the eruption. In addition to the terrestrial applications of these data for understanding active volcanoes and hazards associated with them such as lava flows and explosive eruptions, geologists studying Mars find these data useful as an analog to martian landforms and geologic processes. In late September 2002, a field conference with the theme of Terrestrial Analogs to Mars focused on Mount Etna, allowing Mars geologists to see in person the types of features they can only sample remotely. http://photojournal.jpl.nasa.gov/catalog/PIA03371</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JVGR..295...43J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JVGR..295...43J"><span>Terrestrial laser scanning observations of geomorphic changes and varying lava lake levels at Erebus volcano, Antarctica</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jones, Laura K.; Kyle, Philip R.; Oppenheimer, Clive; Frechette, Jedediah D.; Okal, Marianne H.</p> <p>2015-03-01</p> <p>A Terrestrial Laser Scanning (TLS) instrument was used to image the topography of the Main Crater at Erebus volcano each December in 2008, 2009, and 2010. Our high-spatial resolution TLS scans provide unique insights into annual and decadal scale geomorphic evolution of the summit area when integrated with comparable data collected by an airborne instrument in 2001. We observe both a pattern of subsidence within the Inner Crater of the volcano and an ~ 3 m per-year drop in the lava lake level over the same time period that are suggestive of decreasing overpressure in an underlying magma reservoir. We also scanned the active phonolite lava lake hosted within the Inner Crater, and recorded rapid cyclic fluctuations in the level of the lake. These were sporadically interrupted by minor explosions by bursting gas bubbles at the lake surface. The TLS data permit calculation of lake level rise and fall speeds and associated rates of volumetric change within the lake. These new observations, when considered with prior determinations of rates of lake surface motion and gas output, are indicative of unsteady magma flow in the conduit and its associated variability in gas volume fraction.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss022e008285.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss022e008285.html"><span>Earth Observations taken by the Expedition 22 Crew</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2009-12-09</p> <p>ISS022-E-008285 (9 Dec. 2009) --- Llullaillaco volcano on the Argentina-Chile border is featured in this image photographed by an Expedition 22 crew member on the International Space Station. The summit of Llullaillaco volcano has an elevation of 6,739 meters above sea level, making it the highest historically active volcano in the world. The current Llullaillaco stratovolcano ? a typically high, cone-shaped volcano built from successive layers of thick lava flows and eruption products like ash and rock fragments ? is built on top of an older stratovolcano. The last explosive eruption of the volcano occurred in 1877 based on historical records. This detailed photograph of Llullaillaco illustrates an interesting volcanic feature known as a coulee (top left). Coulees are formed from highly viscous, thick lavas that flow onto a steep surface; as they flow slowly downwards, the top of the flow cools and forms a series of parallel ridges oriented at 90 degrees to the direction of flow (somewhat similar in appearance to the pleats of an accordion). The sides of the flow can also cool faster than the center, leading to the formation of wall-like structures known as flow levees (center).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70192430','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70192430"><span>Buckets of ash track tephra flux from Halema'uma'u Crater, Hawai'i</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Swanson, Don; Wooten, Kelly M.; Orr, Tim R.</p> <p>2009-01-01</p> <p>The 2008–2009 eruption at Kīlauea Volcano's summit made news because of its eight small discrete explosive eruptions and noxious volcanic smog (vog) created from outgassing sulfur dioxide. Less appreciated is the ongoing, weak, but continuous output of tephra, primarily ash, from the new open vent in Halema'uma'u Crater. This tephra holds clues to processes causing the eruption and forming the new crater-in-a-crater, and its flux is important to hazard evaluations.The setting of the vent–easily accessible from the Hawaiian Volcano Observatory (HVO)—is unusually favorable for neardaily tracking of tephra mass flux during this small prolonged basaltic eruption. Recognizing this, scientists from HVO are collecting ash and documenting how ejection masses, components, and chemical compositions vary through time.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.V43A4864M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.V43A4864M"><span>Gravity Change at the Summit of Kīlauea Volcano, Hawaíi, during 2012-2014</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moore, S.; Poland, M. P.; Young, N. K.; Bagnardi, M.; Carbone, D.</p> <p>2014-12-01</p> <p>Monitoring of gravity change at a volcano is a valuable means of assessing mass change at depth and a good complement to other surveillance methods, like deformation and seismicity. At Kīlauea Volcano, Hawaíi, repeated gravity surveys of the summit region have been conducted since 1975, with hundreds of microgals of gravity increase measured at the center of the caldera but without the magnitude of surface uplift through 2008 that would be expected from the gravity increase. This gravity increase was attributed to magma accumulation in void space. Between 2009 and 2012, gravity increase and uplift were coincident, but the uplift was less than expected for the given gravity signal (assuming a basaltic magma density of 2500 kg/m3). The source of both deformation and gravity change was at 1.5 km depth beneath the east margin of Halemáumáu Crater, within Kīlauea Caldera, corresponding to the location of a known shallow magma reservoir. Densification of magma in this reservoir due to degassing through the open summit eruptive vent, active since 2008, is the preferred explanation of the observed gravity change and surface displacements. We conducted gravity surveys in 2013 and 2014 and found that both gravity change and surface displacements were negligible with respect to 2012. We interpret this lack of recent gravity change as an indication that the 1.5-km-depth magma reservoir has reached a steady-state density, where gas loss from the summit vent is compensated for by gas influx from below. Continued gravity surveys should identify any changes in this equilibrium that may presage changes in summit eruptive activity.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JVGR..335..113W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JVGR..335..113W"><span>Eruption of magmatic foams on the Moon: Formation in the waning stages of dike emplacement events as an explanation of ;irregular mare patches;</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wilson, Lionel; Head, James W.</p> <p>2017-04-01</p> <p>Volcanic eruptions on the Moon take place in conditions of low gravity and negligible atmospheric pressure, very different from those on Earth. These differences lead to characteristic lunar versions of hawaiian and strombolian explosive activity, and to the production of unusual eruption products neither predicted nor observed on Earth in the terminal stages of eruptions. These include the unusual mounds and rough (hummocky, blocky) floors of some small-shield summit pit crater floors, elongate depressions and mare flows (similar to those named ;irregular mare patches;, IMPs, by Braden et al., 2014). We examine the ascent and eruption of magma in the waning stages of the eruptive process in small-shield summit pit crater floors and show that many IMP characteristics can be plausibly explained by basaltic magma behavior as the rise rate of the ascending magma slows to zero, volatiles exsolve in the dike and lava lake to form a very vesicular foam, and the dike begins to close. Stresses in the very vesicular and porous lava lake crust produce fractures through which the foam extrudes at a rate determined by its non-Newtonian rheology. Waning-stage extrusion of viscous magmatic foams to the surface produces convex mounds whose physical properties inhibit typical impact crater formation and regolith development, creating an artificially young crater retention age. This mechanism for the production and extrusion of very vesicular magmatic foams is also applicable to waning-stage dike closure associated with pit craters atop dikes, and fissure eruptions in the lunar maria, providing an explanation for many irregular mare patches. This mechanism implies that IMPs and associated mare structures (small shields, pit craters and fissure flows) formed synchronously billions of years ago, in contrast to very young ages (less than 100 million years) proposed for IMPs by some workers.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://ngmdb.usgs.gov/Prodesc/proddesc_62430.htm','USGSPUBS'); return false;" href="http://ngmdb.usgs.gov/Prodesc/proddesc_62430.htm"><span>Preliminary geologic map of Kanaga Volcano, Alaska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Miller, T.P.; Waythomas, C.F.; Nye, C.J.</p> <p>2003-01-01</p> <p>Kanaga Volcano is a 1,300 m (4,287-foot) high, historically active cone-shaped stratovolcano located on the north end of Kanaga Island in the Andreanof Islands Group of the Aleutian Islands. The volcano is undissected, symmetrical in profile, and is characterized by blocky andesitic lava flows, with well-developed levees and steep flow fronts, that emanate radially from, or near, the 200-m-wide summit crater. The lack of dissection of the cone suggests the entire edifice was constructed in post-glacial Holocene time. Historical eruptions were reported in 1791, 1827, 1829, 1904-1906, and 1993-95 (Miller and others, 1998); questionable eruptions occurred in 1763, 1768, 1786, 1790, and 1933. The upper flanks of the cone are very steep (>30°) and flows moving down these steep flows commonly fragment into breccias and lahars. A non-vegetated lahar, or group of lahars, extends from high on the southeast flank of the cone down to the northeast shore of the intracaldera lake. This lahar deposit was observed in 1999 but does not appear to be present on aerial photos taken in 1974 and is assumed to be part of the 1994-95 eruption. Most recent eruptions of Kanag a, including the 1994-95 eruption, were primarily effusive in character with a subordinate explosive component. Lava was extruded from, or near, the summit vent and moved down the flank of the cone in some cases reaching the ocean. In 1994, lava flows going down the very steep north and west flanks broke up into incandescent avalanches tumbling over steep truncated sea cliffs into the Bering Sea. A common feature of Kanaga central vent eruptions is the occurrence of widespread ballistics and accompanying craters. Steam and fine ash plumes rose to 7.5 km ASL and drifted a few tens of kilometers downwind. Plumes such as these are unlikely to deposit significant (i.e., sufficiently thick to leave a permanent record) tephras on other islands downwind.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA22155.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA22155.html"><span>Investigating Mars: Arsia Mons</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2018-01-01</p> <p>The three large aligned Tharsis volcanoes are Arsia Mons, Pavonis Mons and Ascreaus Mons (from south to north). There are collapse features on all three volcanoes, on the southwestern and northeastern flanks. This alignment may indicate a large fracture/vent system was responsible for the eruptions that formed all three volcanoes. The flows originating from Arsia Mons are thought to be the youngest of the region. This VIS image shows part of the northeastern flank of Arsia Mons at the summit caldera. In this region the summit caldera does not have a steep margin most likely due to renewed volcanic flows within this region of the caldera. The scalloped depressions at the top of the image are most likely created by collapse of the roof of lava tubes. Lava tubes originate during eruption event, when the margins of a flow harden around a still flowing lava stream. When an eruption ends these can become hollow tubes within the flow. With time, the roof of the tube may collapse into the empty space below. The tubes are linear, so the collapse of the roof creates a linear depression. Arsia Mons is the southernmost of the Tharsis volcanoes. It is 270 miles (450km) in diameter, almost 12 miles (20km) high, and the summit caldera is 72 miles (120km) wide. For comparison, the largest volcano on Earth is Mauna Loa. From its base on the sea floor, Mauna Loa measures only 6.3 miles high and 75 miles in diameter. A large volcanic crater known as a caldera is located at the summit of all of the Tharsis volcanoes. These calderas are produced by massive volcanic explosions and collapse. The Arsia Mons summit caldera is larger than many volcanoes on Earth. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 17716 Latitude: -8.11179 Longitude: 240.245 Instrument: VIS Captured: 2005-12-12 00:29 https://photojournal.jpl.nasa.gov/catalog/PIA22155</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.V12B..06R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.V12B..06R"><span>3-D Resistivity Structure of La Soufrière Volcano (Guadeloupe): New Insights into the Hydrothermal System and Associated Hazards</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rosas-Carbajal, M.; Nicollin, F.; Komorowski, J. C.; Gibert, D.; Deroussi, S.</p> <p>2015-12-01</p> <p>The 3-D electrical resistivity model of the dome of La Soufrière of Guadeloupe volcano was obtained by inverting more than 23000 electrical resistivity tomography (ERT) and mise-a-la-masse data points. Data acquisition involved 2-D and 3-D protocols, including several pairs of injection electrodes located on opposite sides of the volcano. For the mise-a-la-masse measurements, the contact with a conductive mass was achieved by immersing one of the current electrodes in the Tarissan acid pond (~25 Siemens/m) located in the volcano's summit. The 3-D inversion was performed using a deterministic smoothness-constrained least-squares algorithm with unstructured grid modeling to accurately account for topography. Resistivity contrasts of more than 4 orders of magnitude are observed. A thick and high-angle conductive structure is located in the volcano's southern flank. It extends from the Tarissan Crater's acid pond on the summit to a hot spring region located close to the dome's southern base. This suggests that a large hydrothermal reservoir is located below the southern base of the dome, and connected to the acid pond of the summit's main crater. Therefore, the steep southern flanks of the volcano could be resting on a low-strength, high-angle discontinuity saturated with circulating and possibly pressurized hydrothermal fluids. This could favor partial edifice collapse and lateral directed explosions as shown recurrently in the volcano's history. The resistivity model also reveals smaller hydrothermal reservoirs in the south-east and northern flanks that are linked to the main historical eruptive fractures and to ancient collapse structures such as the Cratère Amic structure. We discuss the main resistivity structures in relation with the geometry of observed faults, historical eruptive fractures, the dynamics of the near surface hydrothermal system manifestations on the dome and the potential implications for future hazards scenarios .</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JVGR..352...55C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JVGR..352...55C"><span>The glaciovolcanic evolution of an andesitic edifice, South Crater, Tongariro volcano, New Zealand</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cole, R. P.; White, J. D. L.; Conway, C. E.; Leonard, G. S.; Townsend, D. B.; Pure, L. R.</p> <p>2018-02-01</p> <p>Unusual deposits, mapped and logged in detail, around the summit area of Tongariro volcano, Tongariro Volcanic Centre, New Zealand indicate that the construction and evolution of a substantial portion of this andesitic stratovolcano was beneath a significant ice cap or summit glacier. As the edifice was built under and through the overlying ice, the style of volcanism evolved in a complex history of growth. Initially, a ≥ 100 m thick, widespread hyaloclastite deposit was emplaced within a subglacial, eruption-formed meltwater lake. This was followed by several phases of effusive and explosive eruptions, producing lava flows and primary volcaniclastic deposits emplaced along channels carved into the ice by heated meltwater. The clastic deposits contain quenched bombs and structural features that indicate waterlain transport and emplacement, and soft sediment deformation. Such accumulation of water on a steep-sided edifice without evidence for a subaerial crater lake, along with lava flow features indicating confinement, suggest that a substantial summit glacier was responsible for the production and retention of water, and the architecture of these deposits. Recent studies at nearby Ruapehu volcano have provided good evidence for glaciovolcanic interactions during the last glacial period. However, until now, little was known of the physical lava-ice interactions in the Centre during the last interglacial period and the earlier part of the last glacial period (110-64 ka). These new data support a reinterpretation for the volcanic evolution of the older Tongariro edifice and the emplacement mechanisms of primary volcaniclastic deposits. They also help to constrain local ice thicknesses and extents at the times of eruption. In addition, this study contributes to a sparse global catalogue of glaciovolcanic deposits of andesitic composition, particularly of primary volcaniclastics preserved at mid-latitude stratovolcanoes. The variety of deposit types indicates a volcano building and evolving with glaciation and is an outstanding example of the types of glaciovolcanic interaction that can occur at one volcano.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70193578','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70193578"><span>Volcano–ice interactions precursory to the 2009 eruption of Redoubt Volcano, Alaska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bleick, Heather A.; Coombs, Michelle L.; Cervelli, Peter F.; Bull, Katharine F.; Wessels, Rick</p> <p>2013-01-01</p> <p>In late summer of 2008, after nearly 20 years of quiescence, Redoubt Volcano began to show signs of abnormal heat flow in its summit crater. In the months that followed, the excess heat triggered melting and ablation of Redoubt's glaciers, beginning at the summit and propagating to lower elevations as the unrest accelerated. A variety of morphological changes were observed, including the creation of ice cauldrons, areas of wide-spread subsidence, punctures in the ice carved out by steam, and deposition from debris flows. In this paper, we use visual observations, satellite data, and a high resolution digital elevation model of the volcanic edifice to calculate ice loss at Redoubt as a function of time. Our aim is to establish from this time series a proxy for heat flow that can be compared to other data sets collected along the same time interval. Our study area consists of the Drift glacier, which flows from the summit crater down the volcano's north slope, and makes up about one quarter of Redoubt's total ice volume of ~ 4 km3. The upper part of the Drift glacier covers the area of recent volcanism, making this part of ice mass most susceptible to the effect of volcanic heating. Moreover, melt water and other flows are channeled down the Drift glacier drainage by topography, leaving the remainder of Redoubt's ice mantle relatively unaffected. The rate of ice loss averaged around 0.1 m3/s over the last four months of 2008, accelerated to over twenty times this value by February 2009, and peaked at greater than 22 m3/s, just prior to the first major explosion on March 22, 2009. We estimate a cumulative ice loss over this period of about 35 million cubic meters (M m3).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.V51G..01P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.V51G..01P"><span>Repeated deflation-inflation events at Kilauea Volcano, Hawai'i: What's up (and down) with that?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Poland, M. P.; Miklius, A.; Lundgren, P.; Sutton, A. J.</p> <p>2011-12-01</p> <p>Cyclic deflation-inflation ("DI") events are a common occurrence at Kilauea Volcano. Most DI events begin with deflation at the summit that generally lasts 12-72 hours and accumulate ~1-5 microradians of tilt as measured on the rim of Kilauea caldera, followed by inflation that is initially rapid but wanes as the net deformation approaches pre-event levels over the course of 12-48 hours. In rare cases, the initial deflation is followed by large-magnitude (~20 microradians) inflation over a few hours followed by hours to days of deflation to pre-event levels. Such DID events have only been recorded during 2000-2004. DI events are also manifested at the Pu'u 'O'o eruptive vent on Kilauea's east rift zone, about 15 km from the summit, and lag summit deformation by about 1-2 hours. For DI events with relatively large-magnitudes (i.e., several microradians) and long-durations (i.e., several days), deformation is manifested along the east rift zone between Pu'u 'O'o and the summit, and eruptive activity at Pu'u 'O'o is impacted with long periods of deflation and inflation associated with eruptive pauses and surges, respectively. During a period of increased magma transport between the summit and Pu'u 'O'o in 2005-2007, DI events recorded at the summit were not detected at Pu'u 'O'o. Since the March 2008 start of Kilauea's ongoing summit eruption, the number of DI events per year has increased from about 5-10 to about 50-60. The level of the summit lava column (continuously visible since early 2010), has generally tracked DI deformation. Surface deformation associated with DI events is measured by tilt, GPS, and InSAR. At the summit, preliminary source models suggest a depth of 1-2 km and a sill-like geometry beneath the center of the caldera, with volume loss and subsequent recovery on the order of tens of thousands of cubic meters with each DI cycle. The localized nature of the DI signal at Pu'u 'O'o argues for a shallow source that is probably less than 1 km deep. At least two mechanisms are consistent with the occurrence of DI events at Kilauea. First, blockage and subsequent clearing of the transport pathway that feeds the shallow summit magma system and conduit to Pu'u 'O'o could cause the observed deformation. A second possibility is that DI events represent convective overturns caused by replacement of degassed magma with gas-rich magma. Such a model is consistent with the increased number of DI events following the onset of Kilauea's summit eruption, when summit gas emissions increased by a factor of about 5, but there have been no changes in degassing rates during periods of frequent (i.e., daily) or rare (i.e., monthly) DI events during 2008-2011. The source of DI events therefore remains a target of continued study.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70016260','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70016260"><span>Deformation monitoring at Nevado del Ruiz, Colombia - October 1985 - March 1988</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Banks, N.G.; Carvajal, C.; Mora, H.; Tryggvason, E.</p> <p>1990-01-01</p> <p>Deformation studies began at Nevado del Ruiz 23 days before the devastating 13 November 1985 eruption, at least 12 months after precursory seismicity and fumarolic activity began. The late start in geodetic monitoring, limited number of stations in the pre-eruption network, and inconsistent patterns in the observed deformation limit conclusions about intrusive activity in the months and weeks prior to the eruption. However, the data require that the magma source of the devastating eruption was either deeper than 7 km or, if shallow, recovered the same volume and position within one week of the eruption. Geodetic monitoring resumed 1 week after the eruption and, by April 1986, included 11 tilt-leveling stations, 38 EDM lines, and 7 short leveling lines - a network capable of detecting emplacement or movement of magma volumes as small as 3 MCM (3 ?? 106 m3) to a depth of 2-3 km (using a point-source model), 10 MCM to 7 km, 50 MCM to 10 km, and 200 MCM to 15 km beneath Ruiz. In addition, 4 telemetered tiltmeters provided the capability of detecting, in real time, the fairly rapid ascent of much smaller magma bodies. Stations established to detect instability of the summit ice cap after the eruption were discontinued in early 1986. The data collected from the geodetic networks have higher than normal variance but demonstrate that little or no cumulative deformation of Ruiz occurred from October 1985 through March 1988. Thus, little, if any, magma intruded above 5 km beneath the summit during or after the 13 November 1985 eruption. This lack of significant intrusive activity agrees with the surprisingly low seismic energy release under Ruiz and makes direct degassing of a large batholith an improbable explanation of the large sulfur flux to date at Ruiz. Part of the variance in the geodetic data results from real but noncumulative deformation that may in part be pressure-buffered by a fairly large geothermal water-gas mixture for which abundant physical evidence exists. Part of the noncumulative deformation, some of the fairly dispersed and low-level seismicity under Ruiz, and some phreatic events appear to correlate with seasonal precipitation patterns. Hence rain/snow-loading and groundwater interaction may cause deformation events and possibly help trigger some phreatic explosions and seismic events at Ruiz and, as search of the literature reveals, at other volcanoes in metastable states. ?? 1990.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JVGR..259....2B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JVGR..259....2B"><span>An overview of the 2009 eruption of Redoubt Volcano, Alaska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bull, Katharine F.; Buurman, Helena</p> <p>2013-06-01</p> <p>In March 2009, Redoubt Volcano, Alaska erupted for the first time since 1990. Explosions ejected plumes that disrupted international and domestic airspace, sent lahars more than 35 km down the Drift River to the coast, and resulted in tephra fall on communities over 100 km away. Geodetic data suggest that magma began to ascend slowly from deep in the crust and reached mid- to shallow-crustal levels as early as May, 2008. Heat flux at the volcano during the precursory phase melted ~ 4% of the Drift glacier atop Redoubt's summit. Petrologic data indicate the deeply sourced magma, low-silica andesite, temporarily arrested at 9-11 km and/or at 4-6 km depth, where it encountered and mixed with segregated stored high-silica andesite bodies. The two magma compositions mixed to form intermediate-silica andesite, and all three magma types erupted during the earliest 2009 events. Only intermediate- and high-silica andesites were produced throughout the explosive and effusive phases of the eruption. The explosive phase began with a phreatic explosion followed by a seismic swarm, which signaled the start of lava effusion on March 22, shortly prior to the first magmatic explosion early on March 23, 2009 (UTC). More than 19 explosions (or “Events”) were produced over 13 days from a single vent immediately south of the 1989-90 lava domes. During that period multiple small pyroclastic density currents flowed primarily to the north and into glacial ravines, three major lahars flooded the Drift River Terminal over 35 km down-river on the coast, tephra fall deposited on all aspects of the edifice and on several communities north and east of the volcano, and at least two, and possibly three lava domes were emplaced. Lightning accompanied almost all the explosions. A shift in the eruptive character took place following Event 9 on March 27 in terms of infrasound signal onsets, the character of repeating earthquakes, and the nature of tephra ejecta. More than nine additional explosions occurred in the next two days, followed by a hiatus in explosive activity between March 29 and April 4. During this hiatus effusion of a lava dome occurred, whose growth slowed on or around April 2. The final explosion pulverized the very poorly vesicular dome on April 4, and was immediately followed by the extrusion of the final dome that ceased growing by July 1, 2009, and reached 72 M m3 in bulk volume. The dome remains as of this writing. Effusion of the final dome in the first month produced blocky intermediate- to high-silica andesite lava, which then expanded by means of lava injection beneath a fracturing and annealing, cooling surface crust. In the first week of May, a seismic swarm accompanied extrusion of an intermediate- to high-silica andesite from the apex of the dome that was highly vesicular and characterized by lower P2O5 content. The dome remained stable throughout its growth period likely due to combined factors that include an emptied conduit system, steady degassing through coalesced vesicles in the effusing lava, and a large crater-pit created by the previous explosions. We estimate the total volume of erupted material from the 2009 eruption to be between ~ 80 M and 120 M m3 dense-rock equivalent (DRE). The aim of this report is to synthesize the results from various datasets gathered both during the eruption and retrospectively, and which are represented by the papers in this publication. We therefore provide an overall view of the 2009 eruption and an introduction to this special issue publication.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993JVGR...58..239B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993JVGR...58..239B"><span>Recent geophysical investigation at Somma-Vesuvio volcanic complex</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Berrino, Giovanna; Coppa, Ugo; De Natale, Giuseppe; Pingue, Folco</p> <p>1993-11-01</p> <p>Activity at Somma-Vesuvio volcanic area in southern Italy is monitored by seismic stations and periodic geodetic and gravity surveys. The seismic network, which consists at present of four vertical stations and one three-component station, recorded an increase in earthquake activity in 1978 and between November 1988 and March 1989. During the later activity, earthquakes were located in a cluster about 3 km beneath the summit of the volcano. Two tide gauges, two tiltmeters and a recording gravimeter are also operating at Somma-Vesuvio. Yearly levelling surveys are conducted along several closed routes that extend from as much as 6 km from the base of the volcano to the summit area. Survey results reveal no significant ground movement since 1959, except for a slight subsidence around the rim of the summit crater. Gravity changes have been larger than the expected 10 μGal uncertainty of the measurements. The lack of contemporary elevation changes implies that the observed gravity changes are the result of a slight change in density structure. The cone of Somma-Vesuvio has been very stable for the last few decades, showing no indications of a buildup to activity. The lack of surface movement should rule out a magma-supply rate to this volcano at the historic eruptive rate of 0.002 km 3/yr.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=10512&hterms=active+volcanoes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dactive%2Bvolcanoes','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=10512&hterms=active+volcanoes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dactive%2Bvolcanoes"><span>Klyuchevskaya Volcano</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2007-01-01</p> <p>The Klyuchevskaya Volcano on Russia's Kamchatka Peninsula continued its ongoing activity by releasing another plume on May 24, 2007. The same day, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured this image, at 01:00 UTC. In this image, a hotspot marks the volcano's summit. Outlined in red, the hotspot indicates where MODIS detected unusually warm surface temperatures. Blowing southward from the summit is the plume, which casts its shadow on the clouds below. Near the summit, the plume appears gray, and it lightens toward the south. With an altitude of 4,835 meters (15,863 feet), Klyuchevskaya (sometimes spelled Klyuchevskoy or Kliuchevskoi) is both the highest and most active volcano on the Kamchatka Peninsula. As part of the Pacific 'Ring of Fire,' the peninsula experiences regular seismic activity as the Pacific Plate slides below other tectonic plates in the Earth's crust. Klyuchevskaya is estimated to have experienced more than 100 flank eruptions in the past 3,000 years. Since its formation 6,000 years ago, the volcano has seen few periods of inactivity. NASA image courtesy the MODIS Rapid Response Team at NASA GSFC. The Rapid Response Team provides daily images of this region.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27178756','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27178756"><span>Pathological autopsy of a patient that underwent a successful ablation of an electrical storm from the left ventricular summit.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hori, Yuichi; Nakahara, Shiro; Mine, Sohtaro; Anjo, Naofumi; Fujii, Akiko; Ueda, Yoshihiko; Taguchi, Isao</p> <p>2016-12-01</p> <p>A 65-year-old man with non-ischemic cardiomyopathy, underwent an autopsy 2 months after the successful ablation of a sustained left ventricular (LV) summit ventricular tachycardia (VT). The patient died due to interstitial pneumonia from amiodarone use. The earliest activation sites of the VT were documented from both inside the anterior interventricular vein (AIV) and epicardial surface. The diameter of the AIV was 3-4 mm, and the radiofrequency (RF) lesion inside the AIV was a slight lesion due to high impedance with a high temperature. The lesion from the epicardial surface was also superficial and insufficient due to neighboring coronary arteries and the existence of epicardial fat. A successful application was performed from the LV endocardium, and diffuse myocardial fibrosis was observed in the mid-myocardium including inside the RF lesions. The actual relationship between the myocardial fibrosis and LV summit VT remains unclear, but this case showed the difficulty of achieving a successful ablation from the epicardial side, when the focus exists in the mid-myocardium around the LV summit.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.V41A2764P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.V41A2764P"><span>Continuous monitoring of Hawaiian volcanoes using thermal cameras</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Patrick, M. R.; Orr, T. R.; Antolik, L.; Lee, R.; Kamibayashi, K.</p> <p>2012-12-01</p> <p>Thermal cameras are becoming more common at volcanoes around the world, and have become a powerful tool for observing volcanic activity. Fixed, continuously recording thermal cameras have been installed by the Hawaiian Volcano Observatory in the last two years at four locations on Kilauea Volcano to better monitor its two ongoing eruptions. The summit eruption, which began in March 2008, hosts an active lava lake deep within a fume-filled vent crater. A thermal camera perched on the rim of Halema`uma`u Crater, acquiring an image every five seconds, has now captured about two years of sustained lava lake activity, including frequent lava level fluctuations, small explosions , and several draining events. This thermal camera has been able to "see" through the thick fume in the crater, providing truly 24/7 monitoring that would not be possible with normal webcams. The east rift zone eruption, which began in 1983, has chiefly consisted of effusion through lava tubes onto the surface, but over the past two years has been interrupted by an intrusion, lava fountaining, crater collapse, and perched lava lake growth and draining. The three thermal cameras on the east rift zone, all on Pu`u `O`o cone and acquiring an image every several minutes, have captured many of these changes and are providing an improved means for alerting observatory staff of new activity. Plans are underway to install a thermal camera at the summit of Mauna Loa to monitor and alert to any future changes there. Thermal cameras are more difficult to install, and image acquisition and processing are more complicated than with visual webcams. Our system is based in part on the successful thermal camera installations by Italian volcanologists on Stromboli and Vulcano. Equipment includes custom enclosures with IR transmissive windows, power, and telemetry. Data acquisition is based on ActiveX controls, and data management is done using automated Matlab scripts. Higher-level data processing, also done with Matlab, includes automated measurements of lava lake level and surface crust velocity, tracking temperatures and hot areas in real-time, and alerts which notify users of notable temperature increases via text messaging. Lastly, real-time image and processed data display, which is vital for effective use of the images at the observatory, is done through a custom Web-based environment . Near real-time webcam images are displayed for the public at hvo.wr.usgs.gov/cams. Thermal cameras are costly, but have proven to be an extremely effective monitoring and research tool at the Hawaiian Volcano Observatory.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRE..122..501P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRE..122..501P"><span>Flank vents and graben as indicators of Late Amazonian volcanotectonic activity on Olympus Mons</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peters, S. I.; Christensen, P. R.</p> <p>2017-03-01</p> <p>Previous studies have focused on large-scale features on Olympus Mons, such as its flank terraces, the summit caldera complex, and the basal escarpment and aureole deposits. Here we identify and characterize previously unrecognized and unmapped small scale features to help further understand the volcanotectonic evolution of this enormous volcano. Using Context Camera, High Resolution Imaging Science Experiment, Thermal Emission Imaging System, High Resolution Stereo Camera Digital Terrain Model, and Mars Orbiter Laser Altimeter data, we identified and characterized the morphology and distribution of 60 flank vents and 84 grabens on Olympus Mons. We find that effusive eruptions have dominated volcanic activity on Olympus Mons in the Late Amazonian. Explosive eruptions were rare, implying volatile-poor magmas and/or a lack of magma-water interactions during the Late Amazonian. The distribution of flank vents suggests dike propagation of hundreds of kilometers and shallow magma storage. Small grabens, not previously observed in lower-resolution data, occur primarily on the lower flanks of Olympus Mons and indicate late-stage extensional tectonism. Based on superposition relationships, we have concluded two stages of development for Olympus Mons during the Late Amazonian: (1) primarily effusive resurfacing and formation of flank vents followed by (2) waning effusive volcanism and graben formation and/or reactivation. This developmental sequence resembles that proposed for Ascraeus Mons and other large Martian shields, suggesting a similar geologic evolution for these volcanoes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.V43B3151A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.V43B3151A"><span>Time-variable magma pressure at Kīlauea Volcano yields constraint on the volume and volatile content of shallow magma storage</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Anderson, K. R.; Patrick, M. R.; Poland, M. P.; Miklius, A.</p> <p>2015-12-01</p> <p>Episodic depressurization-pressurization cycles of Kīlauea Volcano's shallow magma system cause variations in ground deformation, eruption rate, and surface height of the active summit lava lake. The mechanism responsible for these pressure-change cycles remains enigmatic, but associated monitoring signals often show a quasi-exponential temporal history that is consistent with a temporary reduction (or blockage) of supply to Kīlauea's shallow magma storage area. Regardless of their cause, the diverse signals produced by these deflation-inflation (DI) cycles offer an unrivaled opportunity to constrain properties of an active volcano's shallow magma reservoir and relation to its eruptive vents. We model transient behavior at Kīlauea Volcano using a simple mathematical model of an elastic reservoir that is coupled to magma flux through Kīlauea's East Rift Zone (ERZ) at a rate proportional to the difference in pressure between the summit reservoir and the ERZ eruptive vent (Newtonian flow). In this model, summit deflations and ERZ flux reductions are caused by a blockage in supply to the reservoir, while re-inflations occur as the system returns to a steady-state flux condition. The model naturally produces exponential variations in pressure and eruption rate which reasonably, albeit imperfectly, match observations during many of the transient events at Kīlauea. We constrain the model using a diverse range of observations including time-varying summit lava lake surface height and volume change, the temporal evolution of summit ground tilt, time-averaged eruption rate derived from TanDEM-X radar data, and height difference between the summit lava lake and the ERZ eruptive vent during brief eruptive pauses (Patrick et al., 2015). Formulating a Bayesian inverse and including independent prior constraint on magma density, host rock strength, and other properties of the system, we are able to place probabilistic constraints on the volume and volatile content of shallow magma storage, as well as properties of the ERZ conduit and influx of magma into Kīlauea's shallow magma reservoir. Reservoir influx parameters cannot in general be uniquely resolved, but reservoir volume and exsolved volatile content are well constrained; ERZ conduit radius may also be estimated given some simplifying assumptions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70012418','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70012418"><span>Geophysical observations of Kilauea Volcano, Hawaii, 2. Constraints on the magma supply during November 1975-September 1977</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Dzurisin, D.; Anderson, L.A.; Eaton, G.P.; Koyanagi, R.Y.; Lipman, P.W.; Lockwood, J.P.; Okamura, R.T.; Puniwai, G.S.; Sako, M.K.; Yamashita, K.M.</p> <p>1980-01-01</p> <p>Following a 22-month hiatus in eruptive activity, Kilauea volcano extruded roughly 35 ?? 106 m3 of tholeiitic basalt from vents along its middle east rift zone during 13 September-1 October, 1977. The lengthy prelude to this eruption began with a magnitude 7.2 earthquake on 29 November, 1975, and included rapid summit deflation episodes in June, July, and August 1976 and February 1977. Synthesis of seismic, geodetic, gravimetric, and electrical self-potential observations suggests the following model for this atypical Kilauea eruptive cycle. Rapid summit deflation initiated by the November 1975 earthquake reflected substantial migration of magma from beneath the summit region of Kilauea into the east and southwest rift zones. Simultaneous leveling and microgravity observations suggest that 40-90 ?? 106 m3 of void space was created within the summit magma chamber as a result of the earthquake. If this volume was filled by magma from depth before the east rift zone intrusive event of June 1976, the average rate of supply was 6-13 ?? 106 m3/month, a rate that is consistent with the value of 9 ?? 106 m3/month suggested from observations of long-duration Kilauea eruptions. Essentially zero net vertical change was recorded at the summit during the 15-month period beginning with the June 1976 intrusion and ending with the September 1977 eruption. This fact suggests that most magma supplied from depth during this interval was eventually delivered to the east rift zone, at least in part during four rapid summit deflation episodes. Microearthquake epicenters migrated downrift to the middle east rift zone for the first time during the later stages of the February 1977 intrusion, an occurrence presumably reflecting movement of magma into the eventual eruptive zone. This observation was confirmed by tilt surveys in May 1977 that revealed a major inflation center roughly 30 km east of the summit in an area of anomalous steaming and forest kill first noted in March 1976. ?? 1980.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://ngmdb.usgs.gov/Prodesc/proddesc_82895.htm','USGSPUBS'); return false;" href="http://ngmdb.usgs.gov/Prodesc/proddesc_82895.htm"><span>Database for the Geologic Map of the Summit Region of Kilauea Volcano, Hawaii</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Dutton, Dillon R.; Ramsey, David W.; Bruggman, Peggy E.; Felger, Tracey J.; Lougee, Ellen; Margriter, Sandy; Showalter, Patrick; Neal, Christina A.; Lockwood, John P.</p> <p>2007-01-01</p> <p>INTRODUCTION The area covered by this map includes parts of four U.S. Geological Survey (USGS) 7.5' topographic quadrangles (Kilauea Crater, Volcano, Ka`u Desert, and Makaopuhi). It encompasses the summit, upper rift zones, and Koa`e Fault System of Kilauea Volcano and a part of the adjacent, southeast flank of Mauna Loa Volcano. The map is dominated by products of eruptions from Kilauea Volcano, the southernmost of the five volcanoes on the Island of Hawai`i and one of the world's most active volcanoes. At its summit (1,243 m) is Kilauea Crater, a 3 km-by-5 km collapse caldera that formed, possibly over several centuries, between about 200 and 500 years ago. Radiating away from the summit caldera are two linear zones of intrusion and eruption, the east and the southwest rift zones. Repeated subaerial eruptions from the summit and rift zones have built a gently sloping, elongate shield volcano covering approximately 1,500 km2. Much of the volcano lies under water: the east rift zone extends 110 km from the summit to a depth of more than 5,000 m below sea level; whereas, the southwest rift zone has a more limited submarine continuation. South of the summit caldera, mostly north-facing normal faults and open fractures of the Koa`e Fault System extend between the two rift zones. The Koa`e Fault System is interpreted as a tear-away structure that accommodates southward movement of Kilauea's flank in response to distension of the volcano perpendicular to the rift zones. This digital release contains all the information used to produce the geologic map published as USGS Geologic Investigations Series I-2759 (Neal and Lockwood, 2003). The main component of this digital release is a geologic map database prepared using ArcInfo GIS. This release also contains printable files for the geologic map and accompanying descriptive pamphlet from I-2759.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20039819','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20039819"><span>The impact of global warming on Mount Everest.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Moore, G W K; Semple, John L</p> <p>2009-01-01</p> <p>Global warming impacts a wide range of human activities and ecosystems. One unanticipated consequence of the warming is an increase in barometric pressure throughout the troposphere. Mount Everest's extreme height and resulting low barometric pressure places humans near its summit in an extreme state of hypoxia. Here we quantify the degree with which this warming is increasing the barometric pressure near Everest's summit and argue that it is of such a magnitude as to make the mountain, over time, easier to climb.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008SpWea...610004I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008SpWea...610004I"><span>Industry and Government Officials Meet for Space Weather Summit</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Intriligator, Devrie S.</p> <p>2008-10-01</p> <p>Commercial airlines, electric power grids, cell phones, handheld Global Positioning Systems: Although the Sun is less active due to solar minimum, the number and types of situations and technologies that can benefit from up-to-date space weather information are growing. To address this, the second annual summit of the Commercial Space Weather Interest Group (CSWIG) and the National Oceanic and Atmospheric Administration's Space Weather Prediction Center (SWPC) was held on 1 May 2008 during Space Weather Workshop (SWW), in Boulder, Colo.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1984JVGR...20..117D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1984JVGR...20..117D"><span>Geology of El Chichon volcano, Chiapas, Mexico</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Duffield, Wendell A.; Tilling, Robert I.; Canul, Rene</p> <p>1984-03-01</p> <p>The (pre-1982) 850-m-high andesitic stratovolcano El Chichón, active during Pleistocene and Holocene time, is located in rugged, densely forested terrain in northcentral Chiapas, México. The nearest neighboring Holocene volcanoes are 275 km and 200 km to the southeast and northwest, respectively. El Chichón is built on Tertiary siltstone and sandstone, underlain by Cretaceous dolomitic limestone; a 4-km-deep bore hole near the east base of the volcano penetrated this limestone and continued 770 m into a sequence of Jurassic or Cretaceous evaporitic anhydrite and halite. The basement rocks are folded into generally northwest-trending anticlines and synclines. El Chichón is built over a small dome-like structure superposed on a syncline, and this structure may reflect cumulative deformation related to growth of a crustal magma reservoir beneath the volcano. The cone of El Chichón consists almost entirely of pyroclastic rocks. The pre-1982 cone is marked by a 1200-m-diameter (explosion?) crater on the southwest flank and a 1600-m-diameter crater apparently of similar origin at the summit, a lava dome partly fills each crater. The timing of cone and dome growth is poorly known. Field evidence indicates that the flank dome is older than the summit dome, and K-Ar ages from samples high on the cone suggest that the flank dome is older than about 276,000 years. At least three pyroclastic eruptions have occurred during the past 1250 radiocarbon years. Nearly all of the pyroclastic and dome rocks are moderately to highly porphyritic andesite, with plagioclase, hornblende and clinopyroxene the most common phenocrysts. Geologists who mapped El Chichón in 1980 and 1981 warned that the volcano posed a substantial hazard to the surrounding region. This warning was proven to be prophetic by violent eruptions that occurred in March and April of 1982. These eruptions blasted away nearly all of the summit dome, blanketed the surrounding region with tephra, and sent pyroclastic flows down radial drainages on the flanks of the cone; about 0.3 km 3 of material (density of all products normalized to 2.6 g cm -3) was erupted. More debris entered the stratosphere than from any other volcanic eruption within at least the past two decades. Halite and a calcium sulfate mineral (anhydrite?) recovered from the stratospheric cloud, and anhydrite as a common accessory mineral in 1982 juvenile erupted products may reflect contamination of El Chichón magma by the evaporite sequence revealed by drilling.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss033e012648.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss033e012648.html"><span>Earth Observation taken by Expedition 33 crew</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-18</p> <p>ISS033-E-012648 (18 Oct. 2012) --- Isla Santiago is featured in this image photographed by an Expedition 33 crew member on the International Space Station. The island of Santiago is located near the center of the Galapagos Islands off the coast of Ecuador. The Galapagos Islands are situated near the equator, and were formed from volcanism related to a large mantle plume (also known as a hot spot). This hot spot is very close to the tectonic boundary between the Galapagos Ridge, a plate boundary that is also an oceanic spreading center, and the Nazca and Cocos plates. This combination of mantle plumes and tectonic plate movements produces a unique geological environment, including underwater ridges of volcanoes that influence the water circulation around the Galapagos. All of these aspects contribute to the geology and biology of the Galapagos. Isla Santiago itself is formed from a shield volcano also called Santiago. This type of volcanic structure is recognized by low, flat summits surrounded by extensive flow fields of lava; the lava is not very viscous, so it can flow for great distances from the source vents. Several dark lava flow fields are visible in this photograph, the largest along the eastern, western, and southern coastlines. The small Isla Rabida to the south of Isla Santiago is the peak of another, mostly submerged shield volcano. In addition to the lava flows, other volcanic features known as tuff cones are visible on the eastern and western sides of the island. These cones are formed from the rapid interaction of hot flowing lava and water. The water underneath the lava flow flashes to steam explosively, and this both fragments the lava and rapidly cools it, leading to the formation of cones of glassy, relatively fine-grained volcanic material. The most recent volcanic activity on Isla Santiago occurred during 1904 – 1906. The summit ridge of the Santiago shield volcano is located in the northwestern part of the island (center). Also at center is a large but isolated region of green vegetation primarily located on the south-facing slope below the summit ridge. This image was taken during the dry, or garua, season that lasts from June to November. The season is dominated by cooler air transported by the Southeast Trade winds and cooler waters from the Humboldt and Cromwell currents. The combination of cool air and water results in rain falling only in the island highlands, with south- and east-facing slopes receiving the most precipitation. Despite the favorable topographic location, the yellow green color of the vegetation may indicate water (or other) stress.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70014011','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70014011"><span>Geology of El Chichon volcano, Chiapas, Mexico</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Duffield, W.A.; Tilling, R.I.; Canul, R.</p> <p>1984-01-01</p> <p>The (pre-1982) 850-m-high andesitic stratovolcano El Chicho??n, active during Pleistocene and Holocene time, is located in rugged, densely forested terrain in northcentral Chiapas, Me??xico. The nearest neighboring Holocene volcanoes are 275 km and 200 km to the southeast and northwest, respectively. El Chicho??n is built on Tertiary siltstone and sandstone, underlain by Cretaceous dolomitic limestone; a 4-km-deep bore hole near the east base of the volcano penetrated this limestone and continued 770 m into a sequence of Jurassic or Cretaceous evaporitic anhydrite and halite. The basement rocks are folded into generally northwest-trending anticlines and synclines. El Chicho??n is built over a small dome-like structure superposed on a syncline, and this structure may reflect cumulative deformation related to growth of a crustal magma reservoir beneath the volcano. The cone of El Chicho??n consists almost entirely of pyroclastic rocks. The pre-1982 cone is marked by a 1200-m-diameter (explosion?) crater on the southwest flank and a 1600-m-diameter crater apparently of similar origin at the summit, a lava dome partly fills each crater. The timing of cone and dome growth is poorly known. Field evidence indicates that the flank dome is older than the summit dome, and K-Ar ages from samples high on the cone suggest that the flank dome is older than about 276,000 years. At least three pyroclastic eruptions have occurred during the past 1250 radiocarbon years. Nearly all of the pyroclastic and dome rocks are moderately to highly porphyritic andesite, with plagioclase, hornblende and clinopyroxene the most common phenocrysts. Geologists who mapped El Chicho??n in 1980 and 1981 warned that the volcano posed a substantial hazard to the surrounding region. This warning was proven to be prophetic by violent eruptions that occurred in March and April of 1982. These eruptions blasted away nearly all of the summit dome, blanketed the surrounding region with tephra, and sent pyroclastic flows down radial drainages on the flanks of the cone; about 0.3 km3 of material (density of all products normalized to 2.6 g cm-3) was erupted. More debris entered the stratosphere than from any other volcanic eruption within at least the past two decades. Halite and a calcium sulfate mineral (anhydrite?) recovered from the stratospheric cloud, and anhydrite as a common accessory mineral in 1982 juvenile erupted products may reflect contamination of El Chicho??n magma by the evaporite sequence revealed by drilling. ?? 1984.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED528612.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED528612.pdf"><span>Proceedings Report from the Sustainability Education Summit, September 20-21, 2010</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>US Department of Education, 2011</p> <p>2011-01-01</p> <p>The first-ever U. S. Department of Education summit on sustainability, "Sustainability Education Summit: Citizenship and Pathways for a Green Economy," was held on Sept. 20-21, 2010, in Washington, D.C. The Sustainability Education Summit (the Summit) brought together leaders from higher education, business and industry, labor,…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70024091','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70024091"><span>Carbon dioxide emission rate of Kīlauea Volcano: Implications for primary magma and the summit reservoir</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Gerlach, T.M.; McGee, K.A.; Elias, T.; Sutton, A.J.; Doukas, M.P.</p> <p>2002-01-01</p> <p> We report a CO2 emission rate of 8500 metric tons per day (t d−1) for the summit of Kīlauea Volcano, several times larger than previous estimates. It is based on three sets of measurements over 4 years of synchronous SO2 emission rates and volcanic CO2/SO2concentration ratios for the summit correlation spectrometer (COSPEC) traverse. Volcanic CO2/SO2 for the traverse is representative of the global ratio for summit emissions. The summit CO2 emission rate is nearly constant, despite large temporal variations in summit CO2/SO2 and SO2 emission rates. Summit CO2 emissions comprise most of Kīlauea's total CO2 output (∼9000 t d−1). The bulk CO2 content of primary magma determined from CO2emission and magma supply rate data is ∼0.70 wt %. Most of the CO2 is present as exsolved vapor at summit reservoir depths, making the primary magma strongly buoyant. Turbulent mixing with resident reservoir magma, however, prevents frequent eruptions of buoyant primary magma in the summit region. CO2 emissions confirm that the magma supply enters the edifice through the summit reservoir. A persistent several hundred parts per million CO2 anomaly arises from the entry of magma into the summit reservoir beneath a square kilometer area east of Halemaumau pit crater. Since most of the CO2 in primary magma is degassed in the summit, the summit CO2 emission rate is an effective proxy for the magma supply rate. Both scrubbing of SO2 and solubility controls on CO2and S in basaltic melt cause high CO2/SO2 in summit emissions and spatially uncorrelated distributions of CO2 and SO2 in the summit plume.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70019939','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70019939"><span>14C ages and activity for the past 50 ka at Volcán Galeras, Colombia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Banks, N.G.; Calvache, V.M.L.; Williams, S.N.</p> <p>1997-01-01</p> <p>Volcán Galeras is the southernmost Colombian volcano with well-recorded historic activity. The volcano is part of a large and complex volcanic center upon which 400,000 people live. Historic activity has centered on a small-volume cone inside the youngest of several large amphitheaters that breach the west flank of the volcano, away from the city of Pasto (population 300,000). Lava flows (SiO2 between 54.6 and 64.7 wt.%) have dominated activity for more than 1 Ma, but explosive events have also occurred. Joint studies by volcanologists from Colombia, Ecuador, Peru, Bolivia, Argentina, and the United States produced 24 new14C ages and more than 100 stratigraphic sections to interpret the past 50 ka of activity at Galeras, including sector collapse events. The youngest collapse event truncated 12.8 ka lava flows and may have occurred as recently as 8 to 10 ka. Tephra-fall material rapidly thins and becomes finer away from the vent area. The only widespread marker in the < 10 ka section is a biotite-bearing tephra deposited between 4.1 and 4.5 ka from a source south of Galeras. It separates cryoturbated from largely undisturbed layers on Galeras, and thus dates a stratigraphic horizon which is useful in the interpretation of other volcanoes and geotectonics in the equatorial Andes. Pyroclastic flows during the past 50 ka have been small to moderate in volume, but they have left numerous thin deposits on the north and east flanks where lava flows have been impeded by crater and amphitheater walls. Many of the pyroclastic-flow deposits are lithic rich, with fines and clasts so strongly altered by hydrothermal action before eruption that they, as well as the sector collapse deposits, resemble waste dumps of leached cappings from disseminated sulfide deposits more than volcanogenic deposits. This evidence of a long-lived hydrothermal system indicates susceptibility to mass failure and explosive events higher than expected for a volcano built largely by lava flows and modest Vulcanian eruptions. Photographs, written accounts, and our study document historic north and east flank pyroclastic flows as far as 10 km from the summit; however, none have left recognizable deposits in Pasto for more than 40 ka.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997JVGR...77...39B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997JVGR...77...39B"><span>14C ages and activity for the past 50 ka at Volcán Galeras, Colombia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Banks, N. G.; Calvache V, M. L.; Williams, S. N.</p> <p>1997-05-01</p> <p>Volcán Galeras is the southernmost Colombian volcano with well-recorded historic activity. The volcano is part of a large and complex volcanic center upon which 400,000 people live. Historic activity has centered on a small-volume cone inside the youngest of several large amphitheaters that breach the west flank of the volcano, away from the city of Pasto (population 300,000). Lava flows (SiO 2 between 54.6 and 64.7 wt.%) have dominated activity for more than 1 Ma, but explosive events have also occurred. Joint studies by volcanologists from Colombia, Ecuador, Peru, Bolivia, Argentina, and the United States produced 24 new 14C ages and more than 100 stratigraphic sections to interpret the past 50 ka of activity at Galeras, including sector collapse events. The youngest collapse event truncated 12.8 ka lava flows and may have occurred as recently as 8 to 10 ka. Tephra-fall material rapidly thins and becomes finer away from the vent area. The only widespread marker in the < 10 ka section is a biotite-bearing tephra deposited between 4.1 and 4.5 ka from a source south of Galeras. It separates cryoturbated from largely undisturbed layers on Galeras, and thus dates a stratigraphic horizon which is useful in the interpretation of other volcanoes and geotectonics in the equatorial Andes. Pyroclastic flows during the past 50 ka have been small to moderate in volume, but they have left numerous thin deposits on the north and east flanks where lava flows have been impeded by crater and amphitheater walls. Many of the pyroclastic-flow deposits are lithic rich, with fines and clasts so strongly altered by hydrothermal action before eruption that they, as well as the sector collapse deposits, resemble waste dumps of leached cappings from disseminated sulfide deposits more than volcanogenic deposits. This evidence of a long-lived hydrothermal system indicates susceptibility to mass failure and explosive events higher than expected for a volcano built largely by lava flows and modest Vulcanian eruptions. Photographs, written accounts, and our study document historic north and east flank pyroclastic flows as far as 10 km from the summit; however, none have left recognizable deposits in Pasto for more than 40 ka.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2012-11-15/pdf/2012-27710.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2012-11-15/pdf/2012-27710.pdf"><span>77 FR 68117 - Blue Summit Wind, LLC; Notice of Petition for Declaratory Order</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2012-11-15</p> <p>... Wind, LLC; Notice of Petition for Declaratory Order Take notice that on November 6, 2012, pursuant to... Procedure 18 CFR 385.207(a)(2), Blue Summit Wind, LLC (Blue Summit) filed a petition for declaratory order... from the Blue Summit's wind energy generator (Blue Summit Facility) located within the Southwest Power...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss016e010894.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss016e010894.html"><span>Earth Observations taken by the Expedition 16 Crew</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2007-11-17</p> <p>ISS016-E-010894 (17 Nov. 2007) --- Cosiguina Volcano, Nicaragua is featured in this image photographed by an Expedition 16 crewmember on the International Space Station. Three Central American countries (El Salvador, Honduras, and Nicaragua) include coastline along the Gulf of Fonseca that opens into the Pacific Ocean. The southern boundary of the Gulf is a peninsula formed by the Cosiguina volcano illustrated in this view. Cosiguina is a stratovolcano, typically tall cone-shaped structures formed by alternating layers of solidified lava and volcanic rocks (ash, pyroclastic flows, breccias) produced by explosive eruptions. The summit crater is filled with a lake (Laguna Cosiguina). The volcano last erupted in 1859, but its most famous activity occurred in 1835 when it produced the largest historical eruption in Nicaragua. Ash from the 1835 eruption has been found in Mexico, Costa Rica, and Jamaica. The volcano has been quiet since 1859, only an instant in terms of geological time. An earthquake swarm was measured near Cosiguina in 2002, indicating that tectonic forces are still active in the region although the volcano is somewhat isolated from the line of more recently active Central American volcanoes to the northwest and southeast. Intermittently observed gas bubbles in Laguna Cosiguina, and a hot spring along the eastern flank of the volcano are the only indicators of hydrothermal activity at the volcano. The fairly uniform vegetation cover (green) on the volcano's sides also attest to a general lack of gas emissions or "hot spots" on the 872 meter high cone, according to NASA scientists who study the photos downlinked from the orbital outpost.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.V23A3076V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.V23A3076V"><span>Seismic time-frequency analysis of the recent 2015 eruptive activity of Volcán de Colima, Mexico</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vargas-Bracamontes, D. M.; Nava Pichardo, F. A.; Reyes Dávila, G. A.; Arámbula-Mendoza, R.; Martínez Fierros, A.; Ramírez Vázquez, A.; González Amezcua, M.</p> <p>2015-12-01</p> <p>Volcán de Colima is an andesitic stratovolcano located in western Mexico. It is considered the most active volcano in Mexico, with activity characterized mainly by intermittent effusive and explosive episodes. On July 10th-12th 2015, Volcán de Colima underwent its most intense eruptive phase since its Plinian eruption in 1913. A partial collapse of the dome and of the crater wall generated several pyroclastic flows, the largest of which reached almost 10 km to the south of the volcano. Lava flows along with incandescent rockfalls descended through various flanks of the volcanic edifice. Ashfall affected people up to 40 km from the volcano's summit. Inhabitants from the small villages closest to the volcano were evacuated and authorities sealed off a 12 km area. We present an overview of the seismic activity that preceded and accompanied this eruptive phase, with data from the closest broadband and short period seismic stations of the Volcán de Colima monitoring network. We focus on the search of temporal information within the spectral content of the seismic signals. We first employ common time-frequency representations such as Fourier and wavelet transforms, but we also apply more recent techniques proposed for the analysis of non-stationary signals, such as empirical mode decomposition and the synchrosqueezing transform. We present and discuss the performances of these various methods characterizing and quantifying spectral changes which could be used to forecast future eruptive events and to evaluate the course of volcanic processes during ongoing eruptions.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70018732','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70018732"><span>The Uwekahuna Ash Member of the Puna Basalt: product of violent phreatomagmatic eruptions at Kilauea volcano, Hawaii, between 2800 and 2100 14C years ago</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Dzurisin, D.; Lockwood, J.P.; Casadevall, T.J.; Rubin, M.</p> <p>1995-01-01</p> <p>Kilauea volcano's reputation for relatively gentle effusive eruptions belies a violent geologic past, including several large phreatic and phreatomagmatic eruptions that are recorded by Holocene pyroclastic deposits which mantle Kilauea's summit area and the southeast flank of adjacent Mauna Loa volcano. The most widespread of these deposits is the Uwekahuna Ash Member, a basaltic surge and fall deposit emplaced during two or more eruptive episodes separated by a few decades to several centuries. It is infered that the eruptions which produced the Uwekahuna were driven by water interacting with a fluctuating magma column. The volume, extent and character of the Uwekahuna deposits underscore the hazards posed by relatively infrequent but potentially devastating explosive eruptions at Kilauea, as well as at other basaltic volcanoes. -from Authors</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29535248','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29535248"><span>Revisiting Primary Care's Critical Role in Achieving Health Equity: Pisacano Scholars' Reflections from Starfield Summit II.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Park, Brian; Coutinho, Anastasia J; Doohan, Noemi; Jimenez, Jonathan; Martin, Sara; Romano, Max; Wohler, Diana; DeVoe, Jennifer</p> <p>2018-01-01</p> <p>The second Starfield Summit was held in Portland, Oregon, in April 2017. The Summit addressed the role of primary care in advancing health equity by focusing on 4 key domains: social determinants of health in primary care, vulnerable populations, economics and policy, and social accountability. Invited participants represented an interdisciplinary group of primary care clinicians, researchers, educators, policymakers, community leaders, and trainees. The Pisacano Leadership Foundation was one of the Summit sponsors and held its annual leadership symposium in conjunction with the Summit, enabling several Pisacano Scholars to attend the Summit. After the Summit, a small group of current and former Pisacano Scholars formed a writing group to highlight key themes and implications for action discussed at the Summit. The Summit resonated as a call to action for primary care to move beyond identifying existing health inequities and toward the development of interventions that advance health equity, through education, research, and enhanced community partnerships. In doing so, the Summit aimed to build on the foundational work of Dr. Starfield, challenging us to explore the significant role of primary care in truly achieving health equity. © Copyright 2018 by the American Board of Family Medicine.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.7755R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.7755R"><span>Recurrent patterns in fluid geochemistry data prior to phreatic eruptions</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rouwet, Dmitri; Sandri, Laura; Todesco, Micol; Tonini, Roberto; Pecoraino, Giovannella; Diliberto, Iole Serena</p> <p>2016-04-01</p> <p>Not all volcanic eruptions are magma-driven: the sudden evaporation and expansion of heated groundwater may cause phreatic eruptions, where the magma involvement is absent or negligible. Active crater lakes top some of the volcanoes prone to phreatic activity. This kind of eruption may occur suddenly, and without clear warning: on September 27, 2014 a phreatic eruption of Ontake, Japan, occurred without timely precursors, killing 57 tourists near the volcano summit. Phreatic eruptions can thus be as fatal as higher VEI events, due to the lack of recognised precursory signals, and because of their explosive and violent nature. In this study, we tackle the challenge of recognising precursors to phreatic eruptions, by analysing the records of two "phreatically" active volcanoes in Costa Rica, i.e. Poás and Turrialba, respectively with and without a crater lake. These volcanoes cover a wide range of time scales in eruptive behaviour, possibly culminating into magmatic activity, and have a long-term multi-parameter dataset mostly describing fluid geochemistry. Such dataset is suitable for being analysed by objective pattern recognition techniques, in search for recurrent schemes. The aim is to verify the existence and nature of potential precursory patterns, which will improve our understanding of phreatic events, and allow the assessment of the associated hazard at other volcanoes, such as Campi Flegrei or Vulcano, in Italy. Quantitative forecast of phreatic activity will be performed with BET_UNREST, a Bayesian Event Tree tool recently developed within the framework of FP7 EU VUELCO project. The study will combine the analysis of fluid geochemistry data with pattern recognition and phreatic eruption forecast on medium and short-term. The study will also provide interesting hints on the features that promote or hinder phreatic activity in volcanoes that host well-developed hydrothermal circulation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JVGR..329...30B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JVGR..329...30B"><span>Geophysical image of the hydrothermal system of Merapi volcano</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Byrdina, S.; Friedel, S.; Vandemeulebrouck, J.; Budi-Santoso, A.; Suhari; Suryanto, W.; Rizal, M. H.; Winata, E.; Kusdaryanto</p> <p>2017-01-01</p> <p>We present an image of the hydrothermal system of Merapi volcano based on results from electrical resistivity tomography (ERT), self-potential, and CO2 flux mappings. The ERT models identify two distinct low-resistivity bodies interpreted as two parts of a probably interconnected hydrothermal system: at the base of the south flank and in the summit area. In the summit area, a sharp resistivity contrast at ancient crater rim Pasar-Bubar separates a conductive hydrothermal system (20-50 Ω m) from the resistive andesite lava flows and pyroclastic deposits (2000-50,000 Ω m). The existence of preferential fluid circulation along this ancient crater rim is also evidenced by self-potential data. The significative diffuse CO2 degassing (with a median value of 400 g m-2 d-1) is observed in a narrow vicinity of the active crater rim and close to the ancient rim of Pasar-Bubar. The total CO2 degassing across the accessible summital area with a surface of 1.4 ṡ 105 m2 is around 20 t d-1. Before the 2010 eruption, Toutain et al. (2009) estimated a higher value of the total diffuse degassing from the summit area (about 200-230 t d-1). This drop in the diffuse degassing from the summit area can be related to the decrease in the magmatic activity, to the change of the summit morphology, to the approximations used by Toutain et al. (2009), or, more likely, to a combination of these factors. On the south flank of Merapi, the resistivity model shows spectacular stratification. While surficial recent andesite lava flows are characterized by resistivity exceeding 100,000 Ω m, resistivity as low as 10 Ω m has been encountered at a depth of 200 m at the base of the south flank and was interpreted as a presence of the hydrothermal system. No evidence of the hydrothermal system is found on the basis of the north flank at the same depth. This asymmetry might be caused by the asymmetry of the heat supply source of Merapi whose activity is moving south or/and to the asymmetry in topography caused by the presence of Merbabu volcano in the north. On the basis of our results we suggest that stratified pyroclastic deposits on the south flank of Merapi screen and separate the flow of hydrothermal fluids with the gaseous part rising through the crater rims, while the liquid part is flowing downwards to the base of the edifice.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.V51H..02W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.V51H..02W"><span>Seismic Characterization of the June 17, 2007 East Rift Intrusion at Kilauea Volcano</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wilson, D. C.; Uribe, J.; Kamibayashi, S.; Nakata, J.; Okubo, P.</p> <p>2007-12-01</p> <p>An early morning earthquake swarm on Sunday, June 17, 2007 signaled the beginning of a sequence of seismic and deformational activity consistent with an intrusion of magma in the upper East Rift of Kilauea volcano, Hawaii. This culminated in an outbreak of lava from a discontinuous 160 meter long fissure, approximately 6 km west of Pu`u `O`o and 13 km southeast of Kilauea's summit. Here we detail the seismic characteristics and observed deformation accompanying this magmatic intrusion and eruption. Seismic activity began at 0216 Hawaiian Standard Time (HST - UTC minus 10 hours) with 38 events greater than magnitude 2 and over 80 located earthquakes in the first two hours. These earthquakes were centered 1.5-2 km southwest of Mauna Ulu (9 km southeast of Kilauea summit) between 1.5 and 3 km deep. At the same time, tiltmeters at Kilauea's summit began indicating rapid deflation of the summit area. Starting at 0730 HST there was a pronounced eastward shift (by about 4 km) of the center of seismicity to a location just west of Makaopuhi crater. At this time GPS stations began to show extension across the rift in that area. Over the next 7-8 hours, the locus of seismicity continued to migrate eastward with over 70 events located at Makaopuhi crater. Over the next day more than 40 earthquakes occurred with locations ranging from the uppermost east rift to Makaopuhi crater. The next afternoon (June 18) there was another pronounced eastward shift in seismicity with 23 earthquakes, occurring between 1459-1600 HST, centered between Makaopuhi crater and Napau crater. Kilauea summit area tremor levels rose throughout the day on June 17, reaching a peak of 24 times background levels mid-day on the June 18, before beginning a slow decline. Tremor levels along the East Rift showed brief periods of strong activity (4-6 times background levels), and lava was discovered at the surface shortly after one such tremor episode at 0625 HST on June 19. Shortly before noon on the same day, Kilauea tiltmeters indicated an end to summit deflation, and GPS stations indicated a slowing of rift extension which had reached nearly 1 meter of across rift extension. This series of punctuated eastward migrations of seismicity (along with the observed deformational signals) provide a detailed record of the space-time evolution of the June 17 magmatic intrusion and eruption.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2013-03-27/pdf/2013-07047.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2013-03-27/pdf/2013-07047.pdf"><span>78 FR 18619 - Extension of Agency Information Collection Activity Under OMB Review: National Explosives...</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2013-03-27</p> <p>... DEPARTMENT OF HOMELAND SECURITY Transportation Security Administration Extension of Agency Information Collection Activity Under OMB Review: National Explosives Detection Canine Team Program (NEDCTP... Explosives Detection Canine Team Program (NEDCTP) canine handlers. Abstract: The FAMS/CTES Explosives...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss034e005496.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss034e005496.html"><span>Earth Observations taken by Expedition 34 crewmember</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-11-30</p> <p>ISS034-E-005496 (30 Nov. 2012) --- An eruption at the Ulawun volcano, New Britain Island, Papua New Guinea is featured in this image photographed by an Expedition 34 crew member on the International Space Station. Numerous volcanoes contribute to the landmass of the island of New Britain, the largest in the Bismarck Archipelago of Papua New Guinea. One of the most active of these volcanoes, Ulawun, is also the highest with a summit elevation of 2,334 meters. This photograph was taken during the most recent phase of volcanic activity at Ulawun. A white steam and ash plume extends from the summit crater of the stratovolcano towards the northwest (center; note the image is oriented such that north is towards the lower left). The plume begins to broaden as it passes the southwestern coast of Lolobau Island approximately 23 kilometers downwind from its source. Ulawun volcano is also known as “the Father”, with the Bamus volcano to the southwest also known as “the South Son”. The summit of Bamus is obscured by white cumulus clouds (not of volcanic origin) in this image. While Ulawun has been active since at least 1700, the most recent eruptive activity at Bamus occurred in the late 19th century. A large region of ocean surface highlighted by sunglint – sunlight reflecting off the water surface, lending it a mirror-like appearance– is visible to the north-northeast of Ulawun (lower left).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70196639','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70196639"><span>Joint 3-D tomographic imaging of Vp, Vs and Vp/Vs and hypocenter relocation at Sinabung volcano, Indonesia from November to December 2013</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Nugraha, Andri Dian; Indrastuti, Novianti; Kusnandar, Ridwan; Gunawan, Hendra; McCausland, Wendy A.; Aulia, Atin Nur; Harlianti, Ulvienin</p> <p>2018-01-01</p> <p>We conducted travel time tomography using P- and S-wave arrival times of volcanic-tectonic (VT) events that occurred between November and December 2013 to determine the three-dimensional (3D) seismic velocity structure (Vp, Vs, and Vp/Vs) beneath Sinabung volcano, Indonesia in order to delineate geological subsurface structure and to enhance our understanding of the volcanism itself. This was a time period when phreatic explosions became phreatomagmatic and then magma migrated to the surface forming a summit lava dome. We used 4846 VT events with 16,138 P- and 16,138 S-wave arrival time phases recorded by 6 stations for the tomographic inversion. The relocated VTs collapse into three clusters at depths from the surface to sea level, from 2 to 4 km below sea level, and from 5 to 8.5 km below sea level. The tomographic inversion results show three prominent regions of high Vp/Vs (~ 1.8) beneath Sinabung volcano at depths consistent with the relocated earthquake clusters. We interpret these anomalies as intrusives associated with previous eruptions and possibly surrounding the magma conduit, which we cannot resolve with this study. One anomalous region might contain partial melt, at sea level and below the eventual eruption site at the summit. Our results are important for the interpretation of a conceptual model of the “plumbing system” of this hazardous volcano.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70011224','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70011224"><span>Explosive activity associated with the growth of volcanic domes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Newhall, C.G.; Melson, W.G.</p> <p>1983-01-01</p> <p>Domes offer unique opportunities to measure or infer the characteristics of magmas that, at domes and elsewhere, control explosive activity. A review of explosive activity associated with historical dome growth shows that: 1. (1) explosive activity has occurred in close association with nearly all historical dome growth; 2. (2) whole-rock SiO2 content, a crude but widely reported indicator of magma viscosity, shows no systematic relationship to the timing and character of explosions; 3. (3) the average rate of dome growth, a crude indicator of the rate of supply of magma and volatiles to the near-surface enviornment, shows no systematic relationship to the timing or character of explosions; and 4. (4) new studies at Arenal and Mount St. Helens suggest that water content is the dominant control on explosions from water-rich magmas, whereas the crystal content and composition of the interstitial melt (and hence magma viscosity) are equally or more important controls on explosions from water-poor magmas. New efforts should be made to improve current, rather limited techniques for monitoring pre-eruption volatile content and magma viscosity, and thus the explosive potential of magmas. ?? 1983.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18388616','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18388616"><span>State of security at US colleges and universities: a national stakeholder assessment and recommendations.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Greenberg, Sheldon F</p> <p>2007-09-01</p> <p>In 2004 the US Department of Justice, Office of Community Oriented Policing Services, sponsored a National Summit on Campus Public Safety. The summit brought together various stakeholders including campus police and security officials, local police chiefs, college and university faculty and administrators, federal officials, students and parents, and community leaders to address the issues and complexities of campus safety. Delegates to the summit identified key issues in campus safety and security, which included establishing a national center on campus safety, balancing traditional open environments with the need to secure vulnerable sites, improving coordination with state and local police, reducing internal fragmentation, elevating professionalism, and increasing eligibility of campus police and security agencies to compete for federal law enforcement funds. Focus on "active shooters" on campus, resulting from the Virginia Tech incident, should not diminish attention placed on the broader, more prevalent safety and security issues facing the nation's educational campuses. Recommendations resulting from the summit called for establishing a national agenda on campus safety, formation of a national center on campus public safety, and increased opportunity for campus police and security agencies to compete for federal and state funds.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.loc.gov/pictures/collection/hh/item/ne0103.photos.198609p/','SCIGOV-HHH'); return false;" href="https://www.loc.gov/pictures/collection/hh/item/ne0103.photos.198609p/"><span>47. Spring 1935 Harold J. Cook, photographer "Summit Road construction. ...</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>47. Spring 1935 Harold J. Cook, photographer "Summit Road construction. Early stage of road tunnel construction, while tunnel was being driven on Summit Road, Scotts Bluff National Monument." - Scotts Bluff Summit Road, Gering, Scotts Bluff County, NE</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA14456.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA14456.html"><span>Activity at Europe Most Active Volcano Eyed by NASA Spacecraft</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2016-05-27</p> <p>Mt. Etna, Sicily, Italy, is Europe most active volcano. In mid-May 2016, Mt. Etna put on a display of lava fountaining, ash clouds and lava flows. Three of the four summit craters were active. NASA Terra spacecraft acquired this image on May 26, 2016.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.G53B0883M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.G53B0883M"><span>Recent Inflation of Kilauea Volcano During the Ongoing Eruption - Harbinger of Change?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miklius, A.</p> <p>2005-12-01</p> <p>Since the start of the Pu`u `O`o-Kupaianaha eruption on Kilauea's east rift zone in 1983, the volcano's summit has subsided over 1.5 m. Over the last two years, however, leveling and GPS networks have recorded substantial inflation of the summit magma system. Since late 2003, the summit has extended almost 20 cm and risen about 5 cm. Leveling surveys suggest that the locus of inflation has been variable, with maximum uplift shifting from an area in the caldera near Halemaumau to an area in the southeastern part of the caldera, near Keanakako`i crater. Inflation rates have also been highly variable. Starting in mid-January 2005, the inflation rate accelerated for approximately a month, with extension rates across the summit reaching over 60 cm/yr. During this accelerated inflation, on January 25, a brief inflation-deflation transient was recorded on the tiltmeter network, accompanied by volcanic tremor. This event was followed by rapid slip of Kilauea's south flank, raising intriguing possibilities about the relationship between the magmatic system and the rapid slip events. Tiltmeters at the eruption site also recorded inflation, but only until early February, when a deflationary trend began, accompanied by increased eruptive output. The summit continued to inflate until late February, deflated slightly, then resumed inflation in April. These observations suggest that the high inflation rate in January-February was a result of increased magma supply to the summit magma system. In contrast, the most recent previous episode of inflation in 2002 was related to decreased outflow at the eruption site, effectively backing up pressure in the system. That inflation episode ended with the opening of new vents on the flank of Pu`u `O`o that produced high volumes of lava. The two previous, prolonged periods of uplift at the summit were in 1985-1986, before the eruption moved downrift from Pu`u `O`o to Kupaianaha, and 1990-1992, when eruptive activity shifted back to Pu`u `O`o. The current inflation of Kilauea is likely a combination of decreased efficiency of the transport system from the summit to the eruption site and an increase in magma supply. Past behavior of the volcano suggests that such conditions favor a shift in the location of the eruptive vent.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21149843','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21149843"><span>Creating structure for continuation of initiatives.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McClave, Stephen A; Mechanick, Jeffrey I; Kushner, Robert F; DeLegge, Mark H</p> <p>2010-01-01</p> <p>The Summit for Increasing Physician Nutrition Experts brought nutrition leaders from North America together to forge new strategies for promoting greater physician involvement in clinical nutrition. The initiatives derived from the Summit address issues related to education, board certification, research, and clinical practice. To seek consensus from participating societies and to establish a format for the implementation of these initiatives, a council of representatives needs to be formed. The council must be noncompetitive, promote collaboration and facilitation of nutrition activities for participating societies, and ultimately provide service to the healthcare system and individual practitioners. The structure of this council may evolve from a temporary task force to an enduring committee. Participating societies will be asked to fund expenses for their representative and host council meetings on a rotating basis. The council will assume responsibility for pursuing Summit initiatives and providing ongoing communication and collaboration between participant groups.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2010-01-28/pdf/2010-1724.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2010-01-28/pdf/2010-1724.pdf"><span>75 FR 4578 - Extension of Agency Information Collection Activity Under OMB Review: National Explosives...</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2010-01-28</p> <p>... Information Collection Activity Under OMB Review: National Explosives Detection Canine Team Program (NEDCTP... under the National Explosives Detection Canine Team Program. The data is collected electronically... feedback to the Chief of the National Explosives Detection Canine Team Program and instructional staff and...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2013-12-19/pdf/2013-30154.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2013-12-19/pdf/2013-30154.pdf"><span>78 FR 76860 - Agency Information Collection Activities; Proposed Collection; Comments Requested: Inventories...</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2013-12-19</p> <p>...] Agency Information Collection Activities; Proposed Collection; Comments Requested: Inventories, Licensed... currently approved collection. (2) Title of the Form/Collection: Inventories, Licensed Explosives Importers... explosive material inventories of those persons engaged in various activities within the explosives industry...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70017634','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70017634"><span>Emission rates of sulfur dioxide and carbon dioxide from Redoubt Volcano, Alaska during the 1989-1990 eruptions</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Casadevall, T.J.; Doukas, M.P.; Neal, C.A.; McGimsey, R.G.; Gardner, C.A.</p> <p>1994-01-01</p> <p>Airborne measurements of sulfur dioxide emission rates in the gas plume emitted from fumaroles in the summit crater of Redoubt Volcano were started on March 20, 1990 using the COSPEC method. During the latter half of the period of intermittent dome growth and destruction, between March 20 and mid-June 1990, sulfur dioxide emission rates ranged from approximately 1250 to 5850 t/d, rates notably higher than for other convergent-plate boundary volcanoes during periods of active dome growth. Emission rates following the end of dome growth from late June 1990 through May 1991 decreased steadily to less than 75 t/d. The largest mass of sulfur dioxide was released during the period of explosive vent clearing when explosive degassing on December 14-15 injected at least 175,000 ?? 50,000 tonnes of SO2 into the atmosphere. Following the explosive eruptions of December 1989, Redoubt Volcano entered a period of intermittent dome growth from late December 1989 to mid-June 1990 during which Redoubt emitted a total mass of SO2 ranging from 572,000 ?? 90,000 tonnes to 680,000 ?? 90,000 tonnes. From mid-June 1990 through May 1991, the volcano was in a state of posteruption degassing into the troposphere, producing approximately 183,000 ?? 50,000 tonnes of SO2. We estimate that Redoubt Volcano released a minimum mass of sulfur dioxide of approximately 930,000 tonnes. While COSPEC data were not obtained frequently enough to enable their use in eruption prediction, SO2 emission rates clearly indicated a consistent decline in emission rates between March through October 1990 and a continued low level of emission rates through the first half of 1991. Values from consecutive daily measurements of sulfur dioxide emission rates spanning the March 23, 1990 eruption decreased in the three days prior to eruption. That decrease was coincident with a several-fold increase in the frequency of shallow seismic events, suggesting partial sealing of the magma conduit to gas loss that resulted in pressurization of the shallow magma system and an increase in earthquake activity. Unlike the short-term SO2 decrease in March 1990, the long-term decrease of sulfur dioxide emission rates from March 1990 through May 1991 was coincident with low rates of seismic energy release and was interpreted to reflect gradual depressurization of the shallow magma reservoir. The long-term declines in seismic energy release and in SO2 emission rates led AVO scientists to conclude on April 19, 1991 that the potential for further eruptive activity from Redoubt Volcano had diminished, and on this basis, the level of concern color code for the volcano was changed from code yellow (Volcano is restless; earthquake activity is elevated; activity may include extrusion of lava) to code green (Volcano is in its normal 'dormant' state). ?? 1994.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70164312','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70164312"><span>Post-eruptive inflation of Okmok Volcano, Alaska, from InSAR, 2008–2014</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Qu, Feifei; Lu, Zhong; Poland, Michael; Freymueller, Jeffrey T.; Zhang, Qin; Jung, Hyung-Sup</p> <p>2016-01-01</p> <p>Okmok, a ~10-km wide caldera that occupies most of the northeastern end of Umnak Island, is one of the most active volcanoes in the Aleutian arc. The most recent eruption at Okmok during July-August 2008 was by far its largest and most explosive since at least the early 19th century. We investigate post-eruptive magma supply and storage at the volcano during 2008–2014 by analyzing all available synthetic aperture radar (SAR) images of Okmok acquired during that time period using the multi-temporal InSAR technique. Data from the C-band Envisat and X-band TerraSAR-X satellites indicate that Okmok started inflating very soon after the end of 2008 eruption at a time-variable rate of 48-130 mm/y, consistent with GPS measurements. The “model-assisted” phase unwrapping method is applied to improve the phase unwrapping operation for long temporal baseline pairs. The InSAR time-series is used as input for deformation source modeling, which suggests magma accumulating at variable rates in a shallow storage zone at ~3.9 km below sea level beneath the summit caldera, consistent with previous studies. The modeled volume accumulation in the 6 years following the 2008 eruption is ~75% of the 1997 eruption volume and ~25% of the 2008 eruption volume.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A21I2281B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A21I2281B"><span>The contribution of atmospheric proxies to the vertical distribution of ozone over Summit Station, Greenland</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bahramvash Shams, S.; Walden, V. P.; Oltmans, S. J.; Petropavlovskikh, I. V.; Kivi, R.; Thölix, L.</p> <p>2017-12-01</p> <p>The current trend and future concentrations of atmospheric ozone are active areas of research as the effect of the Montreal Protocol is realized. The trend of ozone is due to various chemical and dynamical parameters that create, destroy, and transport atmospheric ozone. These important parameters can be represented by different proxies, but their effects on ozone concentration are not completely understood. Previous studies show that proxies related to ozone have different contributions depending on latitude and altitude. In this study, we use vertical profiles of ozone derived from ozonesondes launched by the NOAA Global Monitoring Division at Summit Station, Greenland from 2005 to 2016. The effects of different proxies on ozone are investigated. Summit Station is located at 3,200 meters above sea level on the Greenland Ice Sheet and is a unique place in the Arctic. We use a stepwise multiple regression (MLR) technique to remove the seasonal cycle of ozone and investigate how the different proxies [solar flux (SF), the Quasi-Biennial Oscillation (QBO), the El Nino-Southern Oscillation index (ENSO), the Arctic Oscillation (AO), eddy heat flux (EHF), the volume of polar stratospheric clouds (VPSC), equivalent latitude (EL), and the tropopause pressure (TP)] affect the vertical distribution of ozone over Summit. The MLR is applied separately to total column ozone (TCO) as well as partial ozone columns (PCO) in the troposphere and the lower, middle, and upper stratosphere. Our results show that dynamical processes are important contributors to ozone concentrations over Summit Station. Tropospheric pressure and the QBO are effective predictors of ozone in the troposphere, lower and middle stratosphere, and to the TCO. The VPSC is an important contributor to changes in ozone in the middle stratosphere. AO explains part of low/mid stratospheric and TCO ozone cycle. A simulation model of ozone over Summit built from the MLR results explains the seasonal cycle and the trends in TCO over Summit with a correlation coefficient (R2) of 82% for TCO. Simulations of PCO in the lower and middle stratosphere range from R2 = 62% to 85%.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFM.S11C1161B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.S11C1161B"><span>Relocation of Seismicity at Mauna Loa, Hawaii and Hengill, Iceland: Improved Delineation of Seismogenic Structures.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baher, S. A.; Thurber, C.; Roberts, K.; Rowe, C.</p> <p>2002-12-01</p> <p>Waveform cross-correlation based refinement of P arrival times and subsequent relocation of earthquakes was determined for events that occurred near the summit of Mauna Loa, Hawaii prior to the March, 1984 eruption and at the Hengill volcano, Iceland during a two-month survey in 1991. Hengill and Mauna Loa volcanoes have a similar rift structure and are hot-spot related volcanoes. The relocated events at Mauna Loa illuminated a previously obscured structure beneath the northwestern flank. Simultaneous inversion for hypocenters and velocity model parameters using the refined arrival times resulted in well-constrained relative earthquake locations with very low arrival time misfits (average RMS 0.03 s). Pre-eruption seismicity from this time period occurred in two groups: a shallow group located near the Mauna Loa summit region, at depths of 1-3 km, and a deeper group located 4-6 km northwest of the summit, at depths of 5-10 km. After relocation, we found that most of the northwest flank earthquakes occurred along a 1 km planar feature striking about 60o E of North in a thin band about 500 m thick. This feature we interpret to be related to a rift zone that was stunted by the buttressing of the adjacent volcanoes Hualalai and Mauna Kea. Previous gravity and magnetic studies provide supporting evidence for the existence of a failed rift zone. Northwest flank focal mechanisms reveal a change in faulting from strike-slip in the southwest to a mix of strike-slip and normal faulting in the northeast. The near summit seismicity that was previously diffuse (4.5 km in width) is reduced to a 6 km long feature (0.5 km in width) extending from depth (6 km) toward the summit. The focal mechanisms analyzed from the summit events showed a mix of faulting without a consistent pattern. Previous studies at Hengill yielded locations of seismic activity that extend from 2-6 km in depth and no apparent correlation with surface features. The existence of non-double-couple focal mechanisms has been confirmed and attributed to high fluid pressures arising from geothermal activity. With the application of these relocation techniques, we hope to improve the resolution of any existing hypocenter clusters and/or fine scale subsurface structures.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70182800','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70182800"><span>Renewed unrest at Mount Spurr Volcano, Alaska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Power, John A.</p> <p>2004-01-01</p> <p>The Alaska Volcano Observatory (AVO),a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys, has detected unrest at Mount Spurr volcano, located about 125 km west of Anchorage, Alaska, at the northeast end of the Aleutian volcanic arc.This activity consists of increased seismicity melting of the summit ice cap, and substantial rates of C02 and H2S emission.The current unrest is centered beneath the volcano's 3374-m-high summit, whose last known eruption was 5000–6000 years ago. Since then, Crater Peak, 2309 m in elevation and 4 km to the south, has been the active vent. Recent eruptions occurred in 1953 and 1992.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20390831','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20390831"><span>Elder abuse awareness and action: the role of state summits.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Anetzberger, Georgia J; Balaswamy, Shantha</p> <p>2010-01-01</p> <p>Increasingly, states are convening summits to identify appropriate local responses to elder abuse. This first-ever nationwide research on state-level elder abuse summits examines what leads to their formation, what they accomplish, and what factors contribute to their success. Study results suggest that two-fifths of the states have held summits, four-fifths of which have been since 2000. Typically the summits were convened by the state department of human services or aging, involved 25-50 participants, and lasted less than 2 years. Nearly 50% of study respondents felt that summit goals had been met, and 60% stated that recommendations were implemented, usually because of committed participants, involvement of the right people, or strong advocacy. State summits can be effective means for galvanizing collective action to address elder abuse as a complex social problem.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1712610D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1712610D"><span>Merapi's lava dome splitting explosion on 18 November 2013 observed by lidar and digital image correlation analysis.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Darmawan, Herlan; Walter, Thomas; Nikkhoo, Mehdi; Richter, Nicole</p> <p>2015-04-01</p> <p>After the 2010 Merapi eruption, the lava dome in the summit of the volcano was firstly growing and then subject to gradual cooling and contraction. In November 2013, a major phreatomagmatic explosion occurred, which caused an eruption column rising over 2 km high and destroyed a number of monitoring instruments in the near field. Bombs were thrown out over 1 km distance. The eruption produced volcanic ash and very fine materials. Deformation data from tilt or EDM showed no wide inflation or deflation associated with this eruption. In addition, high resolution TerraSAR-X data analysis also showed no edifice-wide deformation (Walter et al., 2015). Here we further examine two datasets to determine the morphologic and structural effects of this eruption. First we exploit fixed installed monitoring cameras and use a digital image correlation method to investigate geometric changes before and after the eruption. Second we acquired a high resolution terrestrial Lidar data set after the explosion and compared this another lidar data set acquired before. The result shows details on the splitted dome, the volume of the eruption and thickness of the deposits, and suggests that a new block at the front of the dome is inherently unstable and might break off to form a block and ash flow in the near future. Reference: TR Walter, Subandriyo J, Kirbani S, Bathke H, Suryanto W, Aisyah N, Darmawan H, Jousset P, Lühr BG, Dahm T (2015) Volcano-tectonic control of Merapi's lava dome splitting: The November 2013 fracture observed from high resolution TerraSAR-X data. Tectonophysics 639, 12 January 2015, Pages 23-33. doi:10.1016/j.tecto.2014.11.007</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=GL-2002-001362&hterms=Soufriere&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DSoufriere','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=GL-2002-001362&hterms=Soufriere&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DSoufriere"><span>Ash and Steam, Soufriere Hills Volcano, Monserrat</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2002-01-01</p> <p>International Space Station crew members are regularly alerted to dynamic events on the Earth's surface. On request from scientists on the ground, the ISS crew observed and recorded activity from the summit of Soufriere Hills on March 20, 2002. These two images provide a context view of the island (bottom) and a detailed view of the summit plume (top). When the images were taken, the eastern side of the summit region experienced continued lava growth, and reports posted on the Smithsonian Institution's Weekly Volcanic Activity Report indicate that 'large (50-70 m high), fast-growing, spines developed on the dome's summit. These spines periodically collapsed, producing pyroclastic flows down the volcano's east flank that sometimes reached the Tar River fan. Small ash clouds produced from these events reached roughly 1 km above the volcano and drifted westward over Plymouth and Richmond Hill. Ash predominately fell into the sea. Sulfur dioxide emission rates remained high. Theodolite measurements of the dome taken on March 20 yielded a dome height of 1,039 m.' Other photographs by astronauts of Montserrat have been posted on the Earth Observatory: digital photograph number ISS002-E-9309, taken on July 9, 2001; and a recolored and reprojected version of the same image. Digital photograph numbers ISS004-E-8972 and 8973 were taken 20 March, 2002 from Space Station Alpha and were provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70131497','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70131497"><span>Gravity changes and deformation at Kīlauea Volcano, Hawaii, associated with summit eruptive activity, 2009-2012</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bagnardi, Marco; Poland, Michael P.; Carbone, Daniele; Baker, Scott; Battaglia, Maurizio; Amelung, Falk</p> <p>2014-01-01</p> <p>Analysis of microgravity and surface displacement data collected at the summit of Kīlauea Volcano, Hawaii (USA), between December 2009 and November 2012 suggests a net mass accumulation at ~1.5 km depth beneath the northeast margin of Halema‘uma‘u Crater, within Kīlauea Caldera. Although residual gravity increases and decreases are accompanied by periods of uplift and subsidence of the surface, respectively, the volume change inferred from the modeling of interferometric synthetic aperture radar deformation data can account for only a small portion (as low as 8%) of the mass addition responsible for the gravity increase. We propose that since the opening of a new eruptive vent at the summit of Kīlauea in 2008, magma rising to the surface of the lava lake outgasses, becomes denser, and sinks to deeper levels, replacing less dense gas-rich magma stored in the Halema‘uma‘u magma reservoir. In fact, a relatively small density increase (<200 kg m−3) of a portion of the reservoir can produce the positive residual gravity change measured during the period with the largest mass increase, between March 2011 and November 2012. Other mechanisms may also play a role in the gravity increase without producing significant uplift of the surface, including compressibility of magma, formation of olivine cumulates, and filling of void space by magma. The rate of gravity increase, higher than during previous decades, varies through time and seems to be directly correlated with the volcanic activity occurring at both the summit and the east rift zone of the volcano.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRB..121.5477P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRB..121.5477P"><span>Insights into shallow magmatic processes at Kīlauea Volcano, Hawaíi, from a multiyear continuous gravity time series</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Poland, Michael P.; Carbone, Daniele</p> <p>2016-07-01</p> <p>Continuous gravity data collected near the summit eruptive vent at Kīlauea Volcano, Hawaíi, during 2011-2015 show a strong correlation with summit-area surface deformation and the level of the lava lake within the vent over periods of days to weeks, suggesting that changes in gravity reflect variations in volcanic activity. Joint analysis of gravity and lava level time series data indicates that over the entire time period studied, the average density of the lava within the upper tens to hundreds of meters of the summit eruptive vent remained low—approximately 1000-1500 kg/m3. The ratio of gravity change (adjusted for Earth tides and instrumental drift) to lava level change measured over 15 day windows rose gradually over the course of 2011-2015, probably reflecting either (1) a small increase in the density of lava within the eruptive vent or (2) an increase in the volume of lava within the vent due to gradual vent enlargement. Superimposed on the overall time series were transient spikes of mass change associated with inflation and deflation of Kīlauea's summit and coincident changes in lava level. The unexpectedly strong mass variations during these episodes suggest magma flux to and from the shallow magmatic system without commensurate deformation, perhaps indicating magma accumulation within, and withdrawal from, void space—a process that might not otherwise be apparent from lava level and deformation data alone. Continuous gravity data thus provide unique insights into magmatic processes, arguing for continued application of the method at other frequently active volcanoes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JVGR..280..111M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JVGR..280..111M"><span>Geophysical and geochemical methods applied to investigate fissure-related hydrothermal systems on the summit area of Mt. Etna volcano (Italy)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maucourant, Samuel; Giammanco, Salvatore; Greco, Filippo; Dorizon, Sophie; Del Negro, Ciro</p> <p>2014-06-01</p> <p>A multidisciplinary approach integrating self-potential, soil temperature, heat flux, CO2 efflux and gravity gradiometry signals was used to investigate a relatively small fissure-related hydrothermal system near the summit of Mt. Etna volcano (Italy). Measurements were performed through two different surveys carried out at the beginning and at the end of July 2009, right after the end of the long-lived 2008-2009 flank eruption and in coincidence with an increase in diffuse flank degassing related to a reactivation of the volcano, leading to the opening of a new summit vent (NSEC). The main goal was to use a multidisciplinary approach to the detection of hidden fractures in an area of evident near-surface hydrothermal activity. Despite the different methodologies used and the different geometry of the sampling grid between the surveys, all parameters concurred in confirming that the study area is crossed by faults related with the main fracture systems of the south flank of the volcano, where a continuous hydrothermal circulation is established. Results also highlighted that hydrothermal activity in this area changed both in space and in time. These changes were a clear response to variations in the magmatic system, notably to migration of magma at various depth within the main feeder system of the volcano. The results suggest that this specific area, initially chosen as the optimal test-site for the proposed approach, can be useful in order to get information on the potential reactivation of the summit craters of Mt. Etna.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17836656','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17836656"><span>Fumarolic activity in marie byrd land, antarctica.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lemasurier, W E; Wade, F A</p> <p>1968-10-18</p> <p>Ice towers, probably formed by recent fumarolic activity, have been found around the summit calderas of two volcanoes in Marie Byrd Land. These active (?) volcanoes lie within a broad belt of Mesozoic intrusion and late Cenozoic extrusion that appears to be part of the circum-Pacific orogenic province.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss019e011922.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss019e011922.html"><span>Earth Observation taken by the Expedition 19 crew</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2009-04-28</p> <p>ISS019-E-011922 (28 April 2009) --- Mauna Kea Volcano in Hawaii is featured in this image photographed by an Expedition 19 crewmember on the International Space Station. The island of Hawaii is home to four volcanoes monitored by volcanologists ? Mauna Loa, Hualalai, Kilauea, and Mauna Kea. Mauna Kea is depicted in this view; of the four volcanoes, it is the only one that has not erupted during historical times. The Hawaiian Islands chain, together with the submerged Emperor Chain to the northwest, form an extended line of volcanic islands and seamounts that is thought to record passage of the Pacific Plate over a ?hotspot? (or thermal plume) in the Earth?s mantle. Areas of active volcanism in the southern Hawaiian Islands today mark the general location of the hotspot. This detailed photograph illustrates why the volcano is called Mauna Kea (?white mountain? in Hawaiian). While the neighboring Mauna Loa volcano is a classic shield volcano comprised of dark basaltic lava flows, Mauna Kea experienced more explosive activity during its last eruptive phase. This covered its basalt lava flows with pyroclastic deposits that are visible as the light brown area surrounding snow on the summit (center). Numerous small red to dark gray cinder cones are another distinctive feature of Mauna Loa. The cinder cones represent the most recent type of volcanic activity at the volcano. A small area of buildings and roadways at upper right is the Pohakuloa Training Area. This is the largest US Department of Defense facility in the state of Hawaii. The site is used for U.S. Army and Marine Corps exercises.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss031e041959.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss031e041959.html"><span>Earth Observations taken by the Expedition 31 Crew</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-05-18</p> <p>ISS031-E-041959 (18 May 2012) --- Alaid Volcano in the Kuril Islands of the Russian Federation is featured in this image photographed by an Expedition 31 crew member on the International Space Station. The Kurils chain extends from the Kamchatka Peninsula to the islands of Japan, and contains numerous active volcanoes along its length. Alaid is the highest (2,339 meters above sea level) volcano in the Kuril chain, as well as being the northernmost. The textbook conic morphology of this stratovolcano is marred only by the summit crater, which is breached to the south (center) and highlighted by snow cover. The volcano rises 3,000 meters directly from the floor of the Sea of Okhotsk, with the uppermost part of the volcanic edifice exposed as an island. Much of the sea surface surrounding the volcano has a silver-gray appearance. This mirror-like appearance is due to sunglint, where light reflects off the sea surface and is scattered directly towards the observer onboard the space station. Sunglint is largely absent from a zone directly to the west of the volcano, most likely due to surface wind or water current patterns that change the roughness?and light scattering properties?of the water surface in this area. Volcanoes in the Kurils, and similar island arcs in the Pacific ?ring of fire?, are fed by magma generated along the boundary between two tectonic plates, where one plate is being driven beneath the other (a process known as subduction). Alaid Volcano has been historically active with the most recent confirmed explosive activity occurring in 1996.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=dashboard&pg=7&id=EJ1027105','ERIC'); return false;" href="https://eric.ed.gov/?q=dashboard&pg=7&id=EJ1027105"><span>Learning Optimized: A Conversation with Diane Tavenner</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Jacobs, Joanne</p> <p>2013-01-01</p> <p>Named Charter Leader of the Year in 2010 by the California Charter Schools Association, Diane Tavenner, CEO of Summit Public Schools, is responsible for the generation of multiple transformative schools and a radically different teaching model for Summit. Summit's first charter high school, Summit Prep, launched in 2003, was featured in the film…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss033e022852.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss033e022852.html"><span>Earth observation taken by the Expedition 33 crew.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-11-18</p> <p>ISS033-E-022852 (18 Nov. 2012) --- This view, photographed by an Expedition 33 crew member on the International Space Station, highlights the 24-kilometer wide Aso caldera on the Japanese Island of Kyushu, formed during four explosive eruptions that took place from 300,000 to 90,000 years ago, according to scientists. These major eruptions produced pyroclastic flows and airfall tephra that covered much of Kyushu. As the eruptions emptied the magma chambers beneath the ancient volcanoes, they collapsed ? forming the caldera. Shadows highlight the caldera rim at left, while green vegetation covers slopes between the rim and caldera floor at right. Volcanic activity continued in the caldera following its formation, represented by 17 younger volcanoes including Naka-dake at center. Naka-dake is one of Japan?s most active volcanoes, with ash plumes produced from the summit crater as recently as June 2011. Another prominent crater, Kusasenri, is visible to the west of Naka-dake. This crater is the site of the Aso Volcano Museum as well as pasture for cows and horses. The Aso caldera floor is largely occupied by urban and agricultural land uses that present a gray to white speckled appearance in the image. Fields and cities surround the younger volcanic structures in the caldera center to the north, west, and south. Tan to yellow-brown regions along the crater rim, and along the lower slopes of the younger volcanic highlands in the central caldera, are lacking the dense tree cover indicated by greener areas in the image.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70115013','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70115013"><span>Primative components, crustal assimilation, and magmatic degassing of the 2008 Kilauea summit eruption</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Rowe, Michael C.; Thornber, Carl R.; Orr, Tim R.</p> <p>2015-01-01</p> <p>Simultaneous summit and rift zone eruptions at Kīlauea starting in 2008 reflect a shallow eruptive plumbing system inundated by a bourgeoning supply of new magma from depth. Olivine-hosted melt inclusions, host glass, and bulk lava compositions of magma erupted at both the summit and east rift zone demonstrate chemical continuity at both ends of a well-worn summit-to-rift pipeline. Analysis of glass within dense-cored lapilli erupted from the summit in March – August 2008 show these are not samplings of compositionally distinct magmas stored in the shallow summit magma reservoir, but instead result from remelting and assimilation of fragments from conduit wall and vent blocks. Summit pyroclasts show the predominant and most primitive component erupted to be a homogenous, relatively trace-element-depleted melt that is a compositionally indistinguishable from east rift lava. Based on a “top-down” model for the geochemical variation in east rift zone lava over the past 30 years, we suggest that the apparent absence of a 1982 enriched component in melt inclusions, as well as the proposed summit-rift zone connectivity based on sulfur and mineral chemistry, indicate that the last of the pre-1983 magma has been flushed out of the summit reservoir during the surge of mantle-derived magma from 2003-2007.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GGG....17..375D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GGG....17..375D"><span>Geologic evolution of the Lost City Hydrothermal Field</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Denny, Alden R.; Kelley, Deborah S.; Früh-Green, Gretchen L.</p> <p>2016-02-01</p> <p>The Lost City Hydrothermal Field (LCHF) is a novel serpentinite-hosted vent field located on the Atlantis Massif southern wall. Results of 2 m resolution bathymetry, side scan, and video and still imagery, integrated with direct submersible observations provide the first high-resolution geologic map of the LCHF. These data form the foundation for an evolutionary model for the vent system over the past >120,000 years. The field is located on a down-dropped bench 70 m below the summit of the massif. The bench is capped by breccia and pelagic carbonate deposits underlain by variably deformed and altered serpentinite and gabbroic rocks. Hydrothermal activity is focused at the 60 m tall, 100 m across, massive carbonate edifice "Poseidon," which is venting 91°C fluid. Hydrothermal activity declines south and west of the Poseidon complex and dies off completely at distances greater than 200 m. East of Poseidon, the most recent stage of hydrothermal flow is characterized by egress of diffuse fluids from narrow fissures within a low-angle, anastomosing mylonite zone. South of the area of current hydrothermal activity, there is evidence of two discrete previously unrecognized relict fields. Active venting sites defined by carbonate-filled fissures that cut the carbonate cap rock at the summit of the massif mark the present-day northernmost extent of venting. These spatial relationships reflect multiple stages of field development, the northward migration of venting over time, and the likely development of a nascent field at the massif summit.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5582976','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5582976"><span>The Meta-Leadership Summit for Preparedness Initiative: An Innovative Model to Advance Public Health Preparedness and Response</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Sobelson, Robyn K.; Young, Andrea C.; Marcus, Leonard J.; Dorn, Barry C.; Neslund, Verla S.; McNulty, Eric J.</p> <p>2017-01-01</p> <p>This article reports on the design, evaluation framework, and results from the Meta-Leadership Summit for Preparedness Initiative. The Meta-Leadership Summit for Preparedness was a 5-year initiative based on the premise that national preparedness and emergency response is not solely the responsibility of government. From 2006 to 2011, 36 Meta-Leadership Summits were delivered in communities across the country. Summits were customized, 10-hour leadership development, networking, and community action planning events. They included participation from targeted federal, state, local, nonprofit/philanthropic, and private sector leaders who are directly involved in decision making during a major community or state-wide emergency. A total of 4,971 government, nonprofit, and business leaders attended Meta-Leadership Summits; distribution of attendees by sector was balanced. Ninety-three percent of respondents reported the summit was a valuable use of time, 91% reported the overall quality as “good” or “outstanding,” and 91% would recommend the summit to their colleagues. In addition, approximately 6 months after attending a summit, 80% of respondents reported that they had used meta-leadership concepts or principles. Of these, 93% reported that using meta-leadership concepts or principles had made a positive difference for them and their organizations. The Meta-Leadership Summit for Preparedness Initiative was a value-added opportunity for communities, providing the venue for learning the concepts and practice of meta-leadership, multisector collaboration, and resource sharing with the intent of substantively improving preparedness, response, and recovery efforts. PMID:24251597</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24251597','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24251597"><span>The meta-leadership summit for preparedness initiative: an innovative model to advance public health preparedness and response.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sobelson, Robyn K; Young, Andrea C; Marcus, Leonard J; Dorn, Barry C; Neslund, Verla S; McNulty, Eric J</p> <p>2013-12-01</p> <p>This article reports on the design, evaluation framework, and results from the Meta-Leadership Summit for Preparedness Initiative. The Meta-Leadership Summit for Preparedness was a 5-year initiative based on the premise that national preparedness and emergency response is not solely the responsibility of government. From 2006 to 2011, 36 Meta-Leadership Summits were delivered in communities across the country. Summits were customized, 10-hour leadership development, networking, and community action planning events. They included participation from targeted federal, state, local, nonprofit/philanthropic, and private sector leaders who are directly involved in decision making during a major community or state-wide emergency. A total of 4,971 government, nonprofit, and business leaders attended Meta-Leadership Summits; distribution of attendees by sector was balanced. Ninety-three percent of respondents reported the summit was a valuable use of time, 91% reported the overall quality as "good" or "outstanding," and 91% would recommend the summit to their colleagues. In addition, approximately 6 months after attending a summit, 80% of respondents reported that they had used meta-leadership concepts or principles. Of these, 93% reported that using meta-leadership concepts or principles had made a positive difference for them and their organizations. The Meta-Leadership Summit for Preparedness Initiative was a value-added opportunity for communities, providing the venue for learning the concepts and practice of meta-leadership, multisector collaboration, and resource sharing with the intent of substantively improving preparedness, response, and recovery efforts.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002JVGR..117...69M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002JVGR..117...69M"><span>Persistent summit subsidence at Volcán de Colima, México, 1982 1999: strong evidence against Mogi deflation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Murray, John B.; Wooller, Luke K.</p> <p>2002-09-01</p> <p>This paper re-examines recent ground-deformation measurements at Volcán de Colima, Mexico, to test the hypothesis that the observed movements are in response to pressure changes within a sub-volcanic magma chamber, as suggested for other volcanoes by [Mogi (1958) Earthq. Res. Inst. 36, 99-134]. Measurements of vertical ground deformation across the summit dome complex of Volcán de Colima from a precise levelling network between 1982 and 1999, together with vertical and horizontal displacements derived from dual-frequency GPS measurements in 1994 and 1997, show continuous subsidence. The deformation pattern derived from the levelling shows that subsidence increases towards the summit. The closest stations to the summit (1.1 km distant) show a mean subsidence rate of 5 mm per year compared to the reference station at 2.3 km distance, which may be subsiding itself. Vertical displacements of individual stations since 1982 show that the subsidence has been fairly continuous. The GPS stations, which are distributed more widely and include some close to the edge of the active dome, confirm summit subsidence. The largest measured value, a decrease of 280 mm, or 93 mm subsidence per year, was obtained at the edge of the dome. Horizontal displacements measured during 1994-1997 also show the largest values at the summit, but these are much smaller than the vertical displacements, with the maximum rate of 23 mm per year recorded close to the dome. It is conclusively shown that these measured movements cannot be due to deflation of a buried Mogi source, as vertical and horizontal displacements for some stations are in contrary directions to those predicted by the model, and there is no consistent pattern to the horizontal movements. We attribute the measured deformation to downslope creep, settling and compaction of the edifice, gravitational spreading, or a combination of these processes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.V53A3074S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.V53A3074S"><span>Kilauea's double eruption, 2008-2016: volatile budget and associated hazards</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sutton, A. J.; Elias, T.</p> <p>2016-12-01</p> <p>After 20 years of effusive behavior on Kilauea's East Rift Zone, a surge in magma supply brought about eruptive changes that significantly improved our understanding of volcanic processes and associated hazards. The volcano's summit deformation changes and increase in CO2 emissions signaled the supply surge beginning in 2003, and heralded the opening of the Overlook Vent in 2008. Along with the supply surge and vent opening came a dramatic spike in gas release. Summit SO2 emissions climbed from 0.2 kt/d to over 10 kt/d while East Rift discharge rose from 2 kt/d to about 6 kt/d before both summit and rift emissions began an overall decline in late 2008. In spite of the emissions decline, however, overall gas release from Kilauea remained well above the previous 20-year average through early 2014. Beginning in 2008, the annual gas budget released from the summit and rift combined, was more than 830 kt, 6.7 kt, and 3.7 kt of SO2, HCl, and HF, respectively. Effects of these elevated emissions sustained ongoing human health concerns and caused a multi-year agricultural disaster designation for the Island. The current activity of Kīlauea consists of a predominant summit gas eruption (where lava and ash discharge are trivial compared to gas release) and a more typical rift lava eruption with sufficient lava effusion to reach a community 20 km from the eruptive vent. An updated gas-based lava effusion estimate shows that Kilauea continued to erupt an average of 0.11 km^3 yr^-1 of dense rock equivalent lava between early 2012 and mid-2016. This value shows that despite the new regime of erupting most of its gas budget at the volcano's summit, the Kilauea system is still capable of pushing magma out of its rift at a rate consistent with the long term average.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017CoMP..172...76L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017CoMP..172...76L"><span>Timescales of mixing and storage for Keanakāko`i Tephra magmas (1500-1820 C.E.), Kīlauea Volcano, Hawai`i</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lynn, Kendra J.; Garcia, Michael O.; Shea, Thomas; Costa, Fidel; Swanson, Donald A.</p> <p>2017-09-01</p> <p>The last 2500 years of activity at Kīlauea Volcano (Hawai`i) have been characterized by centuries-long periods dominated by either effusive or explosive eruptions. The most recent period of explosive activity produced the Keanakāko`i Tephra (KT; ca. 1500-1820 C.E.) and occurred after the collapse of the summit caldera (1470-1510 C.E.). Previous studies suggest that KT magmas may have ascended rapidly to the surface, bypassing storage in crustal reservoirs. The storage conditions and rapid ascent hypothesis are tested here using chemical zoning in olivine crystals and thermodynamic modeling. Forsterite contents (Fo; [Mg/(Mg + Fe) × 100]) of olivine core and rim populations are used to identify melt components in Kīlauea's prehistoric (i.e., pre-1823) plumbing system. Primitive (≥Fo88) cores occur throughout the 300+ years of the KT period; they originated from mantle-derived magmas that were first mixed and stored in a deep crustal reservoir. Bimodal olivine populations (≥Fo88 and Fo83-84) record repeated mixing of primitive magmas and more differentiated reservoir components shallower in the system, producing a hybrid composition (Fo85-87). Phase equilibria modeling using MELTS shows that liquidus olivine is not stable at depths >17 km. Thus, calculated timescales likely record mixing and storage within the crust. Modeling of Fe-Mg and Ni zoning patterns (normal, reverse, complex) reveal that KT magmas were mixed and stored for a few weeks to several years before eruption, illustrating a more complex storage history than direct and rapid ascent from the mantle as previously inferred for KT magmas. Complexly zoned crystals also have smoothed compositional reversals in the outer 5-20 µm rims that are out of Fe-Mg equilibrium with surrounding glasses. Diffusion models suggest that these rims formed within a few hours to a few days, indicating that at least one additional, late-stage mixing event may have occurred shortly prior to eruption. Our study illustrates that the lifetimes of KT magmas are more complex than previously proposed, and that most KT magmas did not rise rapidly from the mantle without modification during shallow crustal storage.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JVGR..205...30A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JVGR..205...30A"><span>Seismic activity that accompanied the effusive and explosive eruptions during the 2004-2005 period at Volcán de Colima, Mexico</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Arámbula-Mendoza, R.; Lesage, P.; Valdés-González, C.; Varley, N. R.; Reyes-Dávila, G.; Navarro, C.</p> <p>2011-08-01</p> <p>Volcán de Colima is considered the most active in Mexico. A period of large eruptive activity occurred in 2004-2005. It began as a swarm of long-period events (LPs) in late September 2004, indicating the onset of growth of a new lava dome in its crater. Subsequently, avalanches of incandescent material and pyroclastic flows during a period of approximately 2 months occurred. Then, the activity became more explosive with moderate explosions. Finally, swarms of LPs accompanied the magma ascent and extrusion of small domes and vulcanian explosions with pyroclastic flows in 2005. This eruptive period was investigated with a continuous seismic signal study, cross-correlation of LPs and autoregressive analysis of monochromatic LPs. For the vast majority of the explosions, an increase in the rate of seismic energy was observed with the Seismic Spectral Energy Measurement (SSEM) from 1 to 3 Hz, before each explosive event. This increase in energy is proportional to the increase in the rate of LPs, probably as a result of an increase in the emission rate. Applying the material failure forecasting method (FFM) and using SSEM inverse of parameter, the time of the explosions is estimated as the time when the adjusted line reaches the null value. We observe a systematic delay of a few hours between the real time of occurrence of the explosions and the estimated time. This suggests that more complex processes than pure damaging of the plug occur before the explosions. The swarms associated with the large explosions include a large proportion of LPs with similar waveforms. They form a dozen of families which stay during the whole period of activity and which indicate repetitive sources. Some of the families are active only before the explosions and could therefore be used as early warning. Monochromatic LP events occurred during this period, some of them just some hours before an explosion. However, no clear relationship between their occurrence and the explosions could be found.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.V11B4723M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.V11B4723M"><span>H2O Contents of Submarine and Subaerial Silicic Pyroclasts from Oomurodashi Volcano, Northern Izu-Bonin Arc</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McIntosh, I. M.; Tani, K.; Nichols, A. R.</p> <p>2014-12-01</p> <p>Oomurodashi volcano is an active shallow submarine silicic volcano in the northern Izu-Bonin Arc, located ~20 km south of the inhabited active volcanic island of Izu-Oshima. Oomurodashi has a large (~20km diameter) flat-topped summit located at 100 - 150 metres below sea level (mbsl), with a small central crater, Oomuro Hole, located at ~200 mbsl. Surveys conducted during cruise NT12-19 of R/V Natsushima in 2012 using the remotely-operated vehicle (ROV) Hyper-Dolphin revealed that Oomuro Hole contains numerous active hydrothermal vents and that the summit of Oomurodashi is covered by extensive fresh rhyolitic lava and pumice clasts with little biogenetic or manganese cover, suggesting recent eruption(s) from Oomuro Hole. Given the shallow depth of the volcano summit, such eruptions are likely to have generated subaerial eruption columns. A ~10ka pumiceous subaerial tephra layer on the neighbouring island of Izu-Oshima has a similar chemical composition to the submarine Oomurodashi rocks collected during the NT12-19 cruise and is thought to have originated from Oomurodashi. Here we present FTIR measurements of the H2O contents of rhyolitic pumice from both the submarine deposits sampled during ROV dives and the subaerial tephra deposit on Izu-Oshima, in order to assess magma degassing and eruption processes occurring during shallow submarine eruptions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss037e022473.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss037e022473.html"><span>Earth Observation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2013-10-29</p> <p>ISS037-E-022473 (29 Oct. 2013) --- La Malinche Volcano, Mexico is featured in this image photo graphed by an Expedition 37 crew member on the International Space Station. Located approximately 30 kilometers to the northeast of the city of Puebla, the summit of Volcan la Malinche rises to an elevation of 4,461 meters above sea level. This detailed photograph highlights the snow-dusted summit, and the deep canyons that cut into the flanks of this eroded stratovolcano. La Malinche has not been historically active, but radiometric dating of volcanic rocks and deposits associated with the structure indicate a most recent eruption near the end of the 12th century. NASA scientists cite evidence that lahars, or mudflows, associated with an eruption about 3,100 years ago, affected Pre-Columbian settlements in the nearby Puebla basin. The volcano is enclosed within La Malinche National Park situated within parts of the states of Puebla and Tlaxcala; extensive green forest cover is visible on the lower flanks of the volcano. Access to the volcano is available through roadways, and it is frequently used as a training peak by climbers prior to attempting higher summits. The rectangular outlines of agricultural fields are visible forming an outer ring around the forested area. While the volcano appears to be quiescent, its relatively recent (in geological terms) eruptive activity, and location within the Trans-Mexican Volcanic Belt– a tectonically active region with several current and historically active volcanoes including Popocatepetl to the west and Pico de Orizaba to the east - suggests that future activity is still possible and could potentially pose a threat to the nearby city of Puebla.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.S53E..06B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.S53E..06B"><span>Relative velocity changes using ambient seismic noise at Okmok and Redoubt volcanoes, Alaska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bennington, N. L.; Haney, M. M.; De Angelis, S.; Thurber, C. H.</p> <p>2013-12-01</p> <p>Okmok and Redoubt are two of the most active volcanoes in the Aleutian Arc. Leading up to its most recent eruption, Okmok, a shield volcano on Umnak Island, showed precursors to volcanic activity only five hours before it erupted explosively in July 2008. Redoubt, a stratovolcano located along the Cook Inlet, displayed several months of precursory activity leading up to its March 2009 eruption. Frequent activity at both volcanoes poses a major hazard due to heavy traffic along the North Pacific air routes. Additionally, Okmok is adjacent to several of the world's most productive fisheries and Redoubt is located only 110 miles SW of Anchorage, the major population center of Alaska. For these reasons, it is imperative that we improve our ability to detect early signs of unrest, which could potentially lead to eruptive activity at these volcanoes. We take advantage of continuous waveforms recorded on seismic networks at Redoubt and Okmok in an attempt to identify seismic precursors to the recent eruptions at both volcanoes. We perform seismic interferometry using ambient noise, following Brenguier et al. (2008), in order to probe the subsurface and determine temporal changes in relative seismic velocity from pre- through post-eruption, for the 2008 Okmok and 2009 Redoubt eruptions. In a preliminary investigation, we analyzed 6 months of noise cross-correlation functions averaged over 10-day intervals leading up to the 2009 eruption at Redoubt. During February 2009, station pairs RSO-DFR and RDN-RSO showed a decrease in seismic velocity of ~0.02%. By the beginning of March, the relative velocity changes returned to background levels. Stations RSO and RDN are located within the summit breach, and station DFR is to the north. Although these results are preliminary, it is interesting to note that the decrease in seismic velocity at both station pairs overlaps with the time period when Grapenthin et al. (2012) hypothesize magma in the mid-to-deep crustal reservoir was reheated and migrated to a second shallow reservoir between 2 and 4.5 km depth. This hypothesized shallow magma reservoir is within the sensitivity depth of our ambient noise analysis, and thus the decrease in seismic velocity may be associated with magma movement at shallow depths underneath Redoubt. At the onset of eruption, the relative velocity change at station pair RDN-RSO decreased by ~0.03% while that at RSO-DFR remained at background levels. Notably, this decrease in seismic velocity is observed only at the station pair with a propagation path that traverses the summit breach. Our investigation continues as we search for time variations in the ambient seismic noise signal preceding and following the 2008 Okmok and 2009 Redoubt eruptions and endeavor to identify what those changes may represent.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/5604516-relation-summit-deformation-east-rift-zone-eruptions-kilauea-volcano-hawaii','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/5604516-relation-summit-deformation-east-rift-zone-eruptions-kilauea-volcano-hawaii"><span>Relation of summit deformation to east rift zone eruptions on Kilauea Volcano, Hawaii</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Epp, D.; Decker, R.W.; Okamura, A.T.</p> <p>1983-07-01</p> <p>An inverse relationship exists between the summit deflation of Kilauea, as recorded by summit tilt, and the elevation of associated eruptive vents on the East Rift Zone. This relationship implies that East Rift eruptions drain the summit magma reservior to pressure levels that are dependent on the elevation of the eruptive vents.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://archive.defense.gov/home/features/2012/0512_natosummit','SCIGOVWS'); return false;" href="http://archive.defense.gov/home/features/2012/0512_natosummit"><span>Defense.gov Special Report: NATO 25th Summit Meeting</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.science.gov/aboutsearch.html">Science.gov Websites</a></p> <p></p> <p></p> <p>Representatives from 60 countries and organizations are participating in the 25th NATO summit in <em>Chicago</em> - the said at the conclusion of the alliance's summit in <em>Chicago</em>. Story NATO Secretary General Terms Summit a <em>Chicago</em> have accomplished what they set out to do, NATO Secretary General Anders Fogh Rasmussen said</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.V43G2337E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.V43G2337E"><span>Ambient air quality effects of the 2008-2009 Halema`uma`u eruption on the Island of Hawai`i</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Elias, T.; Sutton, A. J.; Kauahikaua, J. P.; Ray, J. D.; Babb, J. L.</p> <p>2009-12-01</p> <p>While the Halema`uma`u eruption has enlivened volcanologists with the rare opportunity to observe eruptive processes at Kilauea’s summit, it has also caused significant environmental impact on the Island of Hawai`i. Since the beginning of 2008, the combined SO2 emissions from the east rift zone (ERZ) and summit of Kilauea have increased by ~40% as compared to the 2003-2007 long-term average. However, emissions from Kilauea’s summit have increased ~6-fold, averaging 850 t/d during January 2008-August 2009. Although average emissions from the ERZ during this period have been 1-2 times that of the summit, the relative impact of summit emissions is disproportionately large due to the location of the vent and the plume dispersal pattern to downwind communities. Ambient air quality data show that federal standards have been exceeded frequently in various communities on the south half of the island. Between April 2008 and August 2009, primary health standards for SO2 and PM2.5 were exceeded on 41 and 19 occasions respectively in Pahala, located ~30 km downwind of the Kilauea summit under prevailing trade wind conditions. Pahala, which exceeded the SO2 annual standard for 2008, had not exceeded standards prior to the opening of the Halema`uma`u vent in March 2008. In July 2008, the U.S. Secretary of Agriculture designated Hawai`i County a primary natural disaster area due to agricultural losses from volcanic emissions. Many growers of exotic flower crops in the Ka`u district suffered irrecoverable losses. Coffee and macadamia nut farmers also reported damage to their fields. While some livestock farmers reported eye irritation in cattle, more significant damage was observed in the accelerated deterioration of galvanized fencing, gates, pipelines and other infrastructure. The increase in volcanic pollution has spurred health concerns. A rise in respiratory emergencies for visitors to Kilauea caldera in early 2008 led Hawai`i Volcanoes National Park to close areas downwind of the vent. Two recent health studies on the Island of Hawaii conducted prior to the 2008-2009 activity noted increased upper respiratory symptom prevalence in areas of persistent volcanic pollution. The current activity and exposure provides further opportunity to examine thresholds of human response. Local emergency response agencies were pressured to act quickly to address the air quality hazards. A variety of initial approaches led to an official policy of “shelter-in-place” during extreme air quality events. To date, interagency mitigation efforts have included providing Web-available near-real-time SO2 and PM data, developing an SO2 alert index, public education, supplying community fire stations and schools with SO2 monitoring equipment, surveying water quality in home-based drinking water catchment tanks, exploring forecast models, and working to install air handling systems for affected hospitals. While volcanic pollution has been an ongoing issue on the Island since the ERZ eruption became continuous in 1986, the current summit eruption has posed new challenges to Hawai`i residents, who must adapt to living with an active volcano.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA18067.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA18067.html"><span>Nighttime Look at Ambrym Volcano, Vanuatu by NASA Spacecraft</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2014-02-12</p> <p>Ambrym volcano in Vanuatu is one of the most active volcanoes in the world. A large summit caldera contains two active vent complexes, Marum and Benbow is seen in this February 12, 2014 nighttime thermal infrared image from NASA Terra spacecraft.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=MSFC-0203323&hterms=active+volcanoes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dactive%2Bvolcanoes','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=MSFC-0203323&hterms=active+volcanoes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dactive%2Bvolcanoes"><span>Erupting Volcano Mount Etna</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2002-01-01</p> <p>Expedition Five crew members aboard the International Space Station (ISS) captured this overhead look at the smoke and ash regurgitated from the erupting volcano Mt. Etna on the island of Sicily, Italy in October 2002. Triggered by a series of earthquakes on October 27, 2002, this eruption was one of Etna's most vigorous in years. This image shows the ash plume curving out toward the horizon. The lighter-colored plumes down slope and north of the summit seen in this frame are produced by forest fires set by flowing lava. At an elevation of 10,990 feet (3,350 m), the summit of the Mt. Etna volcano, one of the most active and most studied volcanoes in the world, has been active for a half-million years and has erupted hundreds of times in recorded history.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-0203323.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-0203323.html"><span>Earth Science</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2002-10-30</p> <p>Expedition Five crew members aboard the International Space Station (ISS) captured this overhead look at the smoke and ash regurgitated from the erupting volcano Mt. Etna on the island of Sicily, Italy in October 2002. Triggered by a series of earthquakes on October 27, 2002, this eruption was one of Etna's most vigorous in years. This image shows the ash plume curving out toward the horizon. The lighter-colored plumes down slope and north of the summit seen in this frame are produced by forest fires set by flowing lava. At an elevation of 10,990 feet (3,350 m), the summit of the Mt. Etna volcano, one of the most active and most studied volcanoes in the world, has been active for a half-million years and has erupted hundreds of times in recorded history.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/866432','DOE-PATENT-XML'); return false;" href="https://www.osti.gov/servlets/purl/866432"><span>Semiconductor bridge (SCB) igniter</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Bickes, Jr., Robert W.; Schwarz, Alfred C.</p> <p>1987-01-01</p> <p>In an explosive device comprising an explosive material which can be made to explode upon activation by activation means in contact therewith; electrical activation means adaptable for activating said explosive material such that it explodes; and electrical circuitry in operation association with said activation means; there is an improvement wherein said activation means is an electrical material which, at an elevated temperature, has a negative temperature coefficient of electrical resistivity and which has a shape and size and an area of contact with said explosive material sufficient that it has an electrical resistance which will match the resistance requirements of said associated electrical circuitry when said electrical material is operationally associated with said circuitry, and wherein said electrical material is polycrystalline; or said electrical material is crystalline and (a) is mounted on a lattice matched substrate or (b) is partially covered with an intimately contacting metallization area which defines its area of contact with said explosive material.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070031573','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070031573"><span>Operational and Research Musculoskeletal Summit: Summit Recommendations</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Scheuring, Richard A.; Walton, Marlei; Davis-Street, Janis; Smaka, Todd J.; Griffin, DeVon</p> <p>2006-01-01</p> <p>The Medical Informatics and Health Care Systems group in the Office of Space Medicine at NASA Johnson Space Center (JSC) has been tasked by NASA with improving overall medical care on the International Space Station (ISS) and providing insights for medical care for future exploration missions. To accomplish this task, a three day Operational and Research Musculoskeletal Summit was held on August 23-25th, 2005 at Space Center Houston. The purpose of the summit was to review NASA#s a) current strategy for preflight health maintenance and injury screening, b) current treatment methods in-flight, and c) risk mitigation strategy for musculoskeletal injuries or syndromes that could occur or impact the mission. Additionally, summit participants provided a list of research topics NASA should consider to mitigate risks to astronaut health. Prior to the summit, participants participated in a web-based pre-summit forum to review the NASA Space Medical Conditions List (SMCL) of musculoskeletal conditions that may occur on ISS as well as the resources currently available to treat them. Data from the participants were compiled and integrated with the summit proceedings. Summit participants included experts from the extramural physician and researcher communities, and representatives from NASA Headquarters, the astronaut corps, JSC Medical Operations and Human Adaptations and Countermeasures Offices, Glenn Research Center Human Research Office, and the Astronaut Strength, Conditioning, and Reconditioning (ASCR) group. The recommendations in this document are based on a summary of summit discussions and the best possible evidence-based recommendations for musculoskeletal care for astronauts while on the ISS, and include recommendati ons for exploration class missions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009BVol...71..319R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009BVol...71..319R"><span>Chemical and isotopic compositions of thermal springs, fumaroles and bubbling gases at Tacaná Volcano (Mexico-Guatemala): implications for volcanic surveillance</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rouwet, Dmitri; Inguaggiato, Salvatore; Taran, Yuri; Varley, Nicholas; Santiago S., José A.</p> <p>2009-04-01</p> <p>This study presents baseline data for future geochemical monitoring of the active Tacaná volcano-hydrothermal system (Mexico-Guatemala). Seven groups of thermal springs, related to a NW/SE-oriented fault scarp cutting the summit area (4,100m a.s.l.), discharge at the northwest foot of the volcano (1,500-2,000m a.s.l.); another one on the southern ends of Tacaná (La Calera). The near-neutral (pH from 5.8 to 6.9) thermal ( T from 25.7°C to 63.0°C) HCO3-SO4 waters are thought to have formed by the absorption of a H2S/SO2-CO2-enriched steam into a Cl-rich geothermal aquifer, afterwards mixed by Na/HCO3-enriched meteoric waters originating from the higher elevations of the volcano as stated by the isotopic composition (δD and δ18O) of meteoric and spring waters. Boiling temperature fumaroles (89°C at ~3,600m a.s.l. NW of the summit), formed after the May 1986 phreatic explosion, emit isotopically light vapour (δD and δ18O as low as -128 and -19.9‰, respectively) resulting from steam separation from the summit aquifer. Fumarolic as well as bubbling gases at five springs are CO2-dominated. The δ13CCO2 for all gases show typical magmatic values of -3.6 ± 1.3‰ vs V-PDB. The large range in 3He/4He ratios for bubbling, dissolved and fumarolic gases [from 1.3 to 6.9 atmospheric 3He/4He ratio ( R A)] is ascribed to a different degree of near-surface boiling processes inside a heterogeneous aquifer at the contact between the volcanic edifice and the crystalline basement (4He source). Tacaná volcano offers a unique opportunity to give insight into shallow hydrothermal and deep magmatic processes affecting the CO2/3He ratio of gases: bubbling springs with lower gas/water ratios show higher 3He/4He ratios and consequently lower CO2/3He ratios (e.g. Zarco spring). Typical Central American CO2/3He and 3He/4He ratios are found for the fumarolic Agua Caliente and Zarco gases (3.1 ± 1.6 × 1010 and 6.0 ± 0.9 R A, respectively). The L/ S (5.9 ± 0.5) and ( L + S)/ M ratios (9.2 ± 0.7) for the same gases are almost identical to the ones calculated for gases in El Salvador, suggesting an enhanced slab contribution as far as the northern extreme of the Central American Volcanic Arc, Tacaná.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017BVol...79...69T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017BVol...79...69T"><span>The 2012-2016 eruptive cycle at Copahue volcano (Argentina) versus the peripheral gas manifestations: hints from the chemical and isotopic features of fumarolic fluids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tassi, F.; Agusto, M.; Lamberti, C.; Caselli, A. T.; Pecoraino, G.; Caponi, C.; Szentiványi, J.; Venturi, S.; Vaselli, O.</p> <p>2017-10-01</p> <p>This study presents the chemical and isotopic compositions of hydrothermal gases from fumaroles discharging around Copahue volcano (Argentina). Gas samples, including those from two fumaroles at the active summit crater, were collected during 13 surveys carried out by different research teams from 1976 to February 2016. The time-series of H2, CO and light hydrocarbons showed episodic increases related to the main events of the last eruptive cycle that started on 19 July 2012. Concentration peaks were likely caused by enhanced input of hot magmatic fluids affecting the hydrothermal reservoir. These data contrast with the temporal variations shown by Rc/ Ra and δ13C-CO2 values in 2012-2014, which indicated an increasing input from a crustal fluid source. In 2015-2016, however, these isotopic parameters showed opposite trends; their composition became closer to that of the two summit fumaroles, which possibly corresponds to that of the deep magmatic-related end-member. The delayed and reduced compositional changes in the peripheral hydrothermal fluid discharge in response to the 2012-2016 eruptive events suggest that geochemical surveys of these emissions are unlikely to provide premonitory signals of volcanic unrest if the volcanic activity remains centered in the main crater. Instead, an instrument which is able to provide measurements of volcanic gases in the air (e.g. MultiGAS) may be used to detect changes at the summit crater. Otherwise, monitoring of seismic activity and ground deformation, as well as the periodic measurement of the chemistry of the water in the Rio Agrio, which is fed by thermal discharge from the summit crater, seem to represent the most reliable means of monitoring at Copahue. However, the relative compositional stability of the hydrothermal reservoir is a great advantage in terms of geothermal resource exploitation and could encourage new investments in the Copahue geothermal project which was abandoned in the 1990s.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19298421','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19298421"><span>Public health law and the prevention and control of obesity.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dietz, William H; Benken, Donald E; Hunter, Alicia S</p> <p>2009-03-01</p> <p>Obesity constitutes a major public health challenge in the United States. Obesogenic environments have increased owing to the consumption of calorie-dense foods of low nutritional value and the reduction of daily physical activity (e.g., increased portion sizes of meals eaten in and out of the home and fewer physical activity requirements in schools). Policymakers and public health practitioners need to know the best practices and have the competencies to use laws and legal authorities to reverse the obesity epidemic. For instance, statutes and regulations at the federal, state, and local levels of government have been implemented to improve nutritional choices and access to healthy foods, encourage physical activity, and educate consumers about adopting healthy lifestyles. In an effort to understand the application of laws and legal authorities for obesity prevention and control, in June 2008 the Centers for Disease Control and Prevention convened the National Summit on Legal Preparedness for Obesity Prevention and Control. An outcome of this summit will be the publication of the proceeding's white papers written by eight law and subject-matter experts with substantive contributions from summit participants, which will identify actionable options that sectors and organizations at various jurisdictional levels can consider adopting. Law has played a critical role in the control of chronic diseases and the behaviors that lead to them. The use of a systematic legal framework--the use of legislation, regulation, and policy to address the multiple factors that contribute to obesogenic environments--can assist in the development, implementation, and evaluation of a variety of legal approaches for obesity prevention and control. Although public health-focused legal interventions are in an early stage and the direct and indirect impact they may have on the obesity epidemic is not yet understood, efforts such as the summit and white papers should help determine potentially viable legal interventions and assess their impact on population-level change.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2879170','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2879170"><span>Public Health Law and the Prevention and Control of Obesity</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Dietz, William H; Benken, Donald E; Hunter, Alicia S</p> <p>2009-01-01</p> <p>Context: Obesity constitutes a major public health challenge in the United States. Obesogenic environments have increased owing to the consumption of calorie-dense foods of low nutritional value and the reduction of daily physical activity (e.g., increased portion sizes of meals eaten in and out of the home and fewer physical activity requirements in schools). Policymakers and public health practitioners need to know the best practices and have the competencies to use laws and legal authorities to reverse the obesity epidemic. For instance, statutes and regulations at the federal, state, and local levels of government have been implemented to improve nutritional choices and access to healthy foods, encourage physical activity, and educate consumers about adopting healthy lifestyles. Methods: In an effort to understand the application of laws and legal authorities for obesity prevention and control, in June 2008 the Centers for Disease Control and Prevention convened the National Summit on Legal Preparedness for Obesity Prevention and Control. An outcome of this summit will be the publication of the proceeding's white papers written by eight law and subject-matter experts with substantive contributions from summit participants, which will identify actionable options that sectors and organizations at various jurisdictional levels can consider adopting. Findings: Law has played a critical role in the control of chronic diseases and the behaviors that lead to them. The use of a systematic legal framework—the use of legislation, regulation, and policy to address the multiple factors that contribute to obesogenic environments—can assist in the development, implementation, and evaluation of a variety of legal approaches for obesity prevention and control. Conclusions: Although public health–focused legal interventions are in an early stage and the direct and indirect impact they may have on the obesity epidemic is not yet understood, efforts such as the summit and white papers should help determine potentially viable legal interventions and assess their impact on population-level change. PMID:19298421</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JVGR..262..134M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JVGR..262..134M"><span>Magmatic controls on eruption dynamics of the 1950 yr B.P. eruption of San Antonio Volcano, Tacaná Volcanic Complex, Mexico-Guatemala</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mora, Juan Carlos; Gardner, James Edward; Macías, José Luis; Meriggi, Lorenzo; Santo, Alba Patrizia</p> <p>2013-07-01</p> <p>San Antonio Volcano, in the Tacaná Volcanic Complex, erupted ~ 1950 yr. B.P., with a Pelean type eruption that produced andesitic pyroclastic surges and block-and-ash flows destroying part of the volcano summit and producing a horse-shoe shaped crater open to the SW. Between 1950 and 800 yr B.P. the eruption continued with effusive andesites followed by a dacite lava flow and a summit dome, all from a single magma batch. All products consist of phenocrysts and microphenocrysts of zoned plagioclase, amphibole, pyroxene, magnetite ± ilmenite, set in partially crystallized groundmass of glass and microlites of the same mineral phases, except for the lack of amphibole. Included in the andesitic blocks of the block-and-ash flow deposit are basaltic andesite enclaves with elongated and ellipsoidal forms and chilled margins. The enclaves have intersertal textures with brown glass between microphenocrysts of plagioclase, hornblende, pyroxene, and olivine, and minor proportions of phenocrysts of plagioclase, hornblende, and pyroxene. A compositional range obtained of blocks and enclaves resulted from mixing between andesite (866 °C ± 22) and basaltic andesite (enclaves, 932 °C ± 22), which may have triggered the explosive Pelean eruption. Vestiges of that mixing are preserved as complex compositional zones in plagioclase and clinopyroxene-rich reaction rims in amphibole in the andesite. Whole-rock chemistry, geothermometry, experimental petrology and modeling results suggest that after the mixing event the eruption tapped hybrid andesitic magma (≤ 900 °C) and ended with effusive dacitic magma (~ 825 °C), all of which were stored at ~ 200 MPa water pressure. A complex open-system evolution that involved crustal end-members best explains the generation of effusive dacite from the hybrid andesite. Amphibole in the dacite is rimmed by reaction products of plagioclase, orthopyroxene, and Fe-Ti oxides produced by decompression during ascent. Amphibole in the andesite, however, lacks such rims. Because the andesite was at 866 ± 22 °C and the dacite was at ~ 825 °C, the reaction rims indicate that the andesitic magma ascended at 0.023 m s- 1 during the explosive phase of the eruption, whereas the dacitic magma rose more slowly at ~ 0.002-0.004 m s- 1.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JVGR..301..238B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JVGR..301..238B"><span>Volcaniclastic stratigraphy of Gede Volcano, West Java, Indonesia: How it erupted and when</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Belousov, A.; Belousova, M.; Krimer, D.; Costa, F.; Prambada, O.; Zaennudin, A.</p> <p>2015-08-01</p> <p>Gede Volcano, West Java (Indonesia), is located 60 km south of Jakarta within one of the regions with highest population density in the world. Therefore, knowledge of its eruption history is necessary for hazard evaluation, because even a small eruption would have major societal and economic consequences. Here we report the results of the investigation of the stratigraphy of Gede (with the focus on its volcaniclastic deposits of Holocene age) and include 23 new radiocarbon dates. We have found that a major part of the volcanic edifice was formed in the Pleistocene when effusions of lavas of high-silica basalt dominated. During this period the volcano experienced large-scale lateral gravitational failure followed by complete reconstruction of the edifice, formation of the summit subsidence caldera and its partial refilling. After a repose period of > 30,000 years the volcanic activity resumed at the Pleistocene/Holocene boundary. In the Holocene the eruptions were dominantly explosive with magma compositions ranging from basaltic andesite to rhyodacite; many deposits show heterogeneity at the macroscopic hand specimen scale and also in the minerals, which indicates interactions between mafic (basaltic andesite) and silicic (rhyodacite) magmas. Significant eruptions of the volcano were relatively rare and of moderate violence (the highest VEI was 3-4; the largest volume of erupted pyroclasts 0.15 km3). There were 4 major Holocene eruptive episodes ca. 10,000, 4000, 1200, and 1000 yr BP. The volcanic plumes of these eruptions were not buoyant and most of the erupted products were transported in the form of highly concentrated valley-channelized pyroclastic flows. Voluminous lahars were common in the periods between the eruptions. The recent eruptive period of the volcano started approximately 800 years ago. It is characterized by frequent and weak VEI 1-2 explosive eruptions of Vulcanian type and rare small-volume extrusions of viscous lava. We estimate that during last 10,000 years, Gede erupted less than 0.3 km3 DRE (Dense Rock Equivalent) of magma. Such small productivity suggests that the likelihood of future large-volume (VEI ≥ 5) eruptions of the volcano is low, although moderately strong (VEI 3-4) explosive eruptions capable of depositing pyroclastic flows and lahars onto the NE foot of the volcano are more likely.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMNH13B..04W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMNH13B..04W"><span>Volcanic ash: a potential hazard for aviation in Southeast Asia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Whelley, P. L.; Newhall, C. G.</p> <p>2012-12-01</p> <p>There are more than 400 volcanoes in Southeast Asia. Ash from eruptions of Volcanic Explosivity Index 3 (VEI 3) and larger pose local hazards and eruptions of VEI 4 or greater could disrupt trade, travel, and daily life in large parts of the region. To better manage and understand the risk volcanic ash poses to Southeast Asia, this study quantifies the long-term probability of a large eruption sending ash into the Singapore Flight Information Region (FIR), which is a 1,700 km long, quasi-rectangular zone from the Strait of Malacca to the South China Sea. Southeast Asian volcanoes are classified into 6 groups, using satellite data, by their morphology, and where known, their eruptive history. 'Laguna' type are fields of maars, cinder cones and spatter cones, named for the Laguna Volcanic Field, Philippines (13.204, 123.525). 'Kembar' type are broad, gently sloping shield volcanoes with extensive lava flows (Kembar Volcano, Indonesia: 3.850, 097.664). 'Mayon' type volcanoes are open-vent, frequently active, steep sided stratocones with small summit craters, spatter ramparts, small pyroclastic fans (typically < 3 km but up to 5 km) and lava flows (Mayon Volcano, Philippines: 13.257, 123.685). 'Kelut' type are semi-plugged composite cones with dome complexes, pyroclastic fans, and/or debris avalanche deposits (Kelut Volcano, Indonesia: -7.933, 112.308). 'Pinatubo' type are large plugged stratovolcanoes with extensive (tens of km) pyroclastic fans and large summit craters or calderas up to 5 km in diameter (Pinatubo Volcano, Philippines: 15.133, 120.350). 'Toba' type are calderas with long axes > 5 km and surrounded by ignimbrite sheets (Toba Caldera, Indonesia: 02.583, 098.833). In addition silicic dome complexes that might eventually produce large caldera-forming eruptions are also classified as Toba type. The eruptive histories of most volcanoes in Southeast Asia are poorly constrained. Assuming that volcanoes with similar morphologies have had similar eruption histories, we use eruption histories of well-studied examples of each morphologic category as proxy histories for all volcanoes in the class. Results from this work will be used to model volcanic ash contamination scenarios for the Singapore FIR.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70193582','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70193582"><span>Emplacement of the final lava dome of the 2009 eruption of Redoubt Volcano, Alaska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bull, Katharine F.; Anderson, Steven W.; Diefenbach, Angela K.; Wessels, Rick L.; Henton, Sarah M.</p> <p>2013-01-01</p> <p>After more than 8 months of precursory activity and over 20 explosions in 12 days, Redoubt Volcano, Alaska began to extrude the fourth and final lava dome of the 2009 eruption on April 4. By July 1 the dome had filled the pre-2009 summit crater and ceased to grow. By means of analysis and annotations of time-lapse webcam imagery, oblique-image photogrammetry techniques and capture and analysis of forward-looking infrared (FLIR) images, we tracked the volume, textural, effusive-style and temperature changes in near-real time over the entire growth period of the dome. The first month of growth (April 4–May 4) produced blocky intermediate- to high-silica andesite lava (59–62.3 wt.% SiO2) that initially formed a round dome, expanding by endogenous growth, breaking the surface crust in radial fractures and annealing them with warmer, fresh lava. On or around May 1, more finely fragmented and scoriaceous andesite lava (59.8–62.2 wt.% SiO2) began to appear at the top of the dome coincident with increased seismicity and gas emissions. The more scoriaceous lava spread radially over the dome surface, while the dome continued to expand from endogenous growth and blocky lava was exposed on the margins and south side of the dome. By mid-June the upper scoriaceous lava had covered 36% of the dome surface area. Vesicularity of the upper scoriaceous lava range from 55 to 66%, some of the highest vesicularity measurements recorded from a lava dome.We suggest that the stability of the final lava dome primarily resulted from sufficient fracturing and clearing of the conduit by preceding explosions that allowed efficient degassing of the magma during effusion. The dome was thus able to grow until it was large enough to exceed the magmastatic pressure in the chamber, effectively shutting off the eruption.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995BVol...56..660S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995BVol...56..660S"><span>Geology of Tok Island, Korea: eruptive and depositional processes of a shoaling to emergent island volcano</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sohn, Y. K.</p> <p>1995-02-01</p> <p>Detailed mapping of Tok Island, located in the middle of the East Sea (Sea of Japan), along with lithofacies analysis and K-Ar age determinations reveal that the island is of early to late Pliocene age and comprises eight rock units: Trachyte I, Unit P-I, Unit P-II, Trachyandesite (2.7±0.1 Ma), Unit P-III, Trachyte II (2.7±0.1 Ma), Trachyte III (2.5±0.1 Ma) and dikes in ascending stratigraphic order. Trachyte I is a mixture of coherent trachytic lavas and breccias that are interpreted to be subaqueous lavas and related hyaloclastites. Unit P-I comprises massive and inversely graded basaltic breccias which resulted from subaerial gain flows and subaqueous debris flows. A basalt clast from the unit, derived from below Trachyte I, has an age of 4.6±0.4 Ma. Unit P-II is composed of graded and stratified lapilli tuffs with the characteristics of proximal pyroclastic surge deposits. The Trachyandesite is a massive subaerial lava ponded in a volcano-tectonic depression, probably a summit crater. A pyroclastic sequence containing flattened scoria clasts (Unit P-III) and a small volume subaerial lava (Trachyte II) occur above the Trachyandesite, suggesting resumption of pyroclastic activity and lava effusion. Afterwards, shallow intrusion of magma occurred, producing Trachyte III and trachyte dikes. The eight rock units provide an example of the changing eruptive and depositional processes and resultant succession of lithofacies as a seamount builds up above sea level to form an island volcano: Trachyte I represents a wholly subaqueous and effusive stage; Units P-I and P-II represent Surtseyan and Taalian eruptive phases during an explosive transitional (subaqueous to emergent) stage; and the other rock units represent later subaerial effusive and explosive stages. Reconstruction of volcano morphology suggests that the island is a remnant of the south-western crater rim of a volcano the vent of which lies several hundred meters to the north-east.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMIN11B1033P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMIN11B1033P"><span>Information Modeling to Assess Eruptive Behavior and Possible Threats on Mt. Etna, Italy</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pshenichny, C.; Behncke, B.</p> <p>2008-12-01</p> <p>One of the best-studied volcanoes of the world, Mt. Etna in Sicily repeatedly exhibits eruptive scenarios that depart from the behavior considered typical for this volcano. Episodes of intense explosive activity, pyroclastic density currents, dome growth, cone collapse, and phreatomagmatic explosions pose a variety of previously underestimated threats to human lives in the summit area of the volcano. However, retrospective analysis of these events shows that they were likely caused by the same very sets of premises and starting conditions as "normal" effusive eruptions, yet combined in an unexpected, probably unique, way. Physical modeling tells us what may happen in terms of physical parameters but not what events we will actually see on a volcano. Bayesian modeling of volcanoes can unite physical parameters and observed events but, unlike physics, it lacks strictness of terms used to describe the events and, hence, may fail to provide a reasonably impartial, complete and self-consistent set of possible scenarios to be expected. Therefore, a tool is needed to process the observational knowledge as strictly as physical matters are treated by mathematics to provide an appropriate event-based framework for assessment of natural hazards during volcanic eruptions. This task requires a modeling not of the volcano itself but of our knowledge of it, and therefore falls into the field of informatis, knowledge engineering, and artificial intelligence. We involved an approach of artificial intelligence developed specially for the needs of geoscience, the method of event bush. Scenarios inferred from event bush fit the observed ones and allow one to foresee other low-probable events that may occur at the volcano. Application of the event bush provides a more impartial vision of volcanic phenomena and may serve as an intermediary between physical modeling, the expert knowledge and numerical assessment, e.g., by means of Bayesian belief networks.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JVGR..354...74M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JVGR..354...74M"><span>Storage conditions of the mafic and silicic magmas at Cotopaxi, Ecuador</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Martel, Caroline; Andújar, Joan; Mothes, Patricia; Scaillet, Bruno; Pichavant, Michel; Molina, Indira</p> <p>2018-04-01</p> <p>The 2015 reactivation of the Cotopaxi volcano urges us to understand the complex eruptive dynamics of Cotopaxi for better management of a potential major crisis in the near future. Cotopaxi has commonly transitioned from andesitic eruptions of strombolian style (lava flows and scoria ballistics) or nuées ardentes (pyroclastic flows and ash falls) to highly explosive rhyolitic ignimbrites (pumiceous pyroclastic flows), which entail drastically different risks. To better interpret geophysical and geochemical signals, Cotopaxi magma storage conditions were determined via existing phase-equilibrium experiments that used starting materials chemically close to the Cotopaxi andesites and rhyolites. The results suggest that Cotopaxi's most mafic andesites (last erupted products) can be stored over a large range of depth from 7 km to ≥16 km below the summit (pressure from 200 to ≥400 MPa), 1000 °C, NNO +2, and contain 4.5-6.0±0.7 wt% H2O dissolved in the melt in equilibrium with 30-40% phenocrysts of plagioclase, two pyroxenes, and Fe-Ti oxides. These mafic andesites sometimes evolve towards more silicic andesites by cooling to 950 °C. Rhyolitic magmas are stored at 200-300 MPa (i.e. 7-11 km below the summit), 750 °C, NNO +2, and contain 6-8 wt% H2O dissolved in a nearly aphyric melt (<5% phenocrysts of plagioclase, biotite, and Fe-Ti oxides). Although the andesites produce the rhyolitic magmas by fractional crystallization, the Cotopaxi eruptive history suggests reactivation of either reservoirs at distinct times, likely reflecting flux or time fluctuations during deep magma recharge.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.V21A0390W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.V21A0390W"><span>Time Series Radar Observations of a Growing Lava Dome</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wadge, G.; Macfarlane, D. G.; Odbert, H. M.; James, M. R.; Hole, J. K.; Ryan, G.; Bass, V.; de Angelis, S.; Pinkerton, H.; Robertson, D. A.; Loughlin, S. C.</p> <p>2007-12-01</p> <p>Exogenous growth of Peléean lava domes occurs by addition of lava from a central summit vent and mass wasting on the flanks as rockfalls and pyroclastic flows, forming an apron of talus. We observed this process at the Soufrière Hills Volcano, Montserrat between 30 March and 10 April 2006 using a ground-based imaging mm-wave radar, AVTIS, to measure the shape of the dome surface.From a time series of range and intensity measurements at a distance of six kilometres we measured the topographic evolution of the lava dome. The locus of talus deposition moved to the southeast with time and the talus surface grew upwards on average at about 2 metres per day. The AVTIS measurements show an acceleration in lava extrusion rate on 5 April, with a 2-day lag in the equivalent rockfall seismicity record. We account for the budget of lava addition and dispersal during the eleven days of measurements using: AVTIS range measurements to measure the talus growth (7.2 Mm3, 67%), AVTIS range and intensity measurements to measure the summit lava growth (1.7 Mm3, 16%), and rockfall seismicity and visual observations to measure the pyroclastic flow deposits (1.8 Mm3, 17%). This gives an overall dense rock equivalent extrusion rate of about 9.7 m3s-1. These figures demonstrate how efficient non-explosive lava dome growth can be in generating large volumes of primary clastic deposits, and how this process could also reduce the propensity for large hazardous pyroclastic flows. andrews.ac.uk/~mmwave/mmwave/avtis.shtml</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70176203','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70176203"><span>Insights into shallow magmatic processes at Kīlauea Volcano, Hawaiʻi, from a multiyear continuous gravity time series</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Poland, Michael P.; Carbone, Daniele</p> <p>2016-01-01</p> <p>Continuous gravity data collected near the summit eruptive vent at Kīlauea Volcano, Hawaiʻi, during 2011–2015 show a strong correlation with summit-area surface deformation and the level of the lava lake within the vent over periods of days to weeks, suggesting that changes in gravity reflect variations in volcanic activity. Joint analysis of gravity and lava level time series data indicates that over the entire time period studied, the average density of the lava within the upper tens to hundreds of meters of the summit eruptive vent remained low—approximately 1000–1500 kg/m3. The ratio of gravity change (adjusted for Earth tides and instrumental drift) to lava level change measured over 15 day windows rose gradually over the course of 2011–2015, probably reflecting either (1) a small increase in the density of lava within the eruptive vent or (2) an increase in the volume of lava within the vent due to gradual vent enlargement. Superimposed on the overall time series were transient spikes of mass change associated with inflation and deflation of Kīlauea's summit and coincident changes in lava level. The unexpectedly strong mass variations during these episodes suggest magma flux to and from the shallow magmatic system without commensurate deformation, perhaps indicating magma accumulation within, and withdrawal from, void space—a process that might not otherwise be apparent from lava level and deformation data alone. Continuous gravity data thus provide unique insights into magmatic processes, arguing for continued application of the method at other frequently active volcanoes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70036224','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70036224"><span>The Augustine magmatic system as revealed by seismic tomography and relocated earthquake hypocenters from 1994 through 2009</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Syracuse, E.M.; Thurber, C.H.; Power, J.A.</p> <p>2011-01-01</p> <p>We incorporate 14 years of earthquake data from the Alaska Volcano Observatory with data from a 1975 controlled-source seismic experiment to obtain the three-dimensional P and S wave velocity structure and the first high-precision earthquake locations at Augustine Volcano to be calculated in a fully three-dimensional velocity model. Velocity tomography shows two main features beneath Augustine: a narrow, high-velocity column beneath the summit, extending from ???2 km depth to the surface, and elevated velocities on the south flank. Our relocation results allow a thorough analysis of the spatio-temoral patterns of seismicity and the relationship to the magmatic and eruptive activity. Background seismicity is centered beneath the summit at an average depth of 0.6 km above sea level. In the weeks leading to the January 2006 eruption of Augustine, seismicity focused on a NW-SE line along the trend of an inflating dike. A series of drumbeat earthquakes occurred in the early weeks of the eruption, indicating further magma transport through the same dike system. During the six months following the onset of the eruption, the otherwise quiescent region 1 to 5 km below sea level centered beneath the summit became seismically active with two groups of earthquakes, differentiated by frequency content. The deep longer-period earthquakes occurred during the eruption and are interpreted as resulting from the movement of magma toward the summit, and the post-eruptive shorter-period earthquakes may be due to the relaxation of an emptied magma tube. The seismicity subsequently returned to its normal background rates and patterns. Copyright 2011 by the American Geophysical Union.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFM.V22E..10G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFM.V22E..10G"><span>CO2 Degassing at Kilauea Volcano: Implications for Primary Magma, Summit Reservoir Dynamics, and Magma Supply Monitoring</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gerlach, T. M.; McGee, K. A.; Elias, T.; Sutton, A. J.; Doukas, M. P.</p> <p>2001-12-01</p> <p>We report a new CO2 emission rate of 8,500 tons/day (t/d) for the summit of Kilauea Volcano, a result several times larger than previous estimates. It is based on 12 experiments on three occasions over four years constraining the SO2 emission rate and the average CO2/SO2 of emissions along the 5.4-km summit COSPEC traverse (by COSPEC, NDIR CO2 analyzer, and CP-FTIR). The core of the summit plume is at ground level along the traverse and gives average CO2/SO2 values that are representative of the overall summit emission, even though CO2 and SO2 variations are commonly uncorrelated. CO2 and SO2 concentrations exceed background by 200-1,000 ppm and 1-7 ppm respectively. Nighttime measurements exclude Park auto exhaust as a source of CO2. The summit CO2 emission rate is nearly constant (95% confidence interval = 300 t/d), despite variable summit SO2 emission rates (62-240 t/d) and CO2/SO2 (54-183). Including other known CO2 emissions on the volcano (mainly from the Pu`u `O`o eruption) gives a total emission rate of about 8,800 t/d. Thus summit CO2 emissions comprise 97% of the total known CO2 output, consistent with the hypothesis that all primary magma supplied to Kilauea arrives under the summit caldera and is thoroughly degassed of excess CO2. A persistent large CO2 anomaly of 200-1,000 ppm indicates the entry to the summit reservoir is beneath a km2-area east of Halemaumau. The bulk CO2 content of primary magma is about 0.70 wt%, inferred from the CO2 emission rate and Kilauea's magma supply rate (0.18 km3/y [Cayol et al., Science, 288, 2343, 2000]). Most of the CO2 is present as exsolved vapor (3.6-11.7 vol%) at summit reservoir depths (2-7 km), making the primary magma strongly buoyant. Magma chamber replenishment models show that robust turbulent mixing of primary and reservoir magma prevents frequent eruption of buoyant primary magma in the summit region. The escape of 90-95% of the CO2 from the summit reservoir provides a potential proxy for monitoring the magma supply rate. Streaming CO2-rich vapor causes fractional degassing of H2O and SO2 from reservoir magma, but scrubbing minimizes summit SO2 emissions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/pp/pp1732/pp1732b/index.html','USGSPUBS'); return false;" href="https://pubs.usgs.gov/pp/pp1732/pp1732b/index.html"><span>Geothermal disruption of ice at Mount Spurr Volcano, 2004 - 2006: An unusual manifestation of volcanic unrest in Alaska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Coombs, Michelle L.; Neal, Christina A.; Wessels, Rick L.; McGimsey, Robert G.</p> <p>2006-01-01</p> <p>Mount Spurr, a 3,374-m-high stratovolcano in the Cook Inlet region of Alaska, showed signs of volcanic unrest beginning in 2004 and lasting through 2006. These signs included increases in heat flow, seismicity, and gas flux, which we interpret as the results of a magmatic intrusion in mid-2004. In response, debris-laden meltwater beneath the glacier in Mount Spurr's geothermally active summit basin accumulated as the overlying snow and ice melted. As heat output increased, the icecap subsided into a growing cavity over a meltwater lake, similar to that observed during subglacial volcanic activity in Iceland. An ice plug collapsed into the lake sometime between June 20 and July 8, 2004, forming an ice cauldron that continued to grow in diameter during 2004 and 2005. A freefall of ice and snow into the lake likely caused a mixture of water and debris to be displaced rapidly upward and outward along preexisting englacial and, possibly, subglacial pathways leading away and downslope from the summit basin. Where these pathways intersected crevasses or other weak points in the sloping icefield, the mixture debouched onto the surface, producing dark, fluid debris flows. In summer 2004, the occurrence of two sets of debris flows separated in time by as long as a week suggests two pulses of summit ice collapse, each producing a surge of water and debris from the lake. A single debris flow was also emplaced on May 2, 2005. This event, which was captured by a Web camera, occurred simultaneously with a lake-level drop of ~15 m. To the east of the ice cauldron, a spillway that fed the debris flows has apparently maintained a relatively constant lake level for months at a time. Aerial photographs show that the spillway is in the direction of a breach in the summit crater. Melting of snow and ice at the summit has continued through 2006, with a total meltwater volume of ~5.4 million m3 as of March 2006.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.U53A0712H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.U53A0712H"><span>The Glacier National Park GLORIA Project: A new US Target Region for Alpine Plant Monitoring Installed in the Northern Rocky Mountains, Montana</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Holzer, K.; Fagre, D.</p> <p>2004-12-01</p> <p>The Global Observation Research Initiative in Alpine Environments (GLORIA) is an international research network whose purpose is to assess climate change impacts on vegetation in alpine environments worldwide. A standard protocol was developed by the international office in Vienna, Austria, and has specific site requirements and techniques that allow sites to be compared worldwide. This protocol requires four summits to be selected within a target region, covering zonal differences of subalpine to nival, and on each of these summits intensive vegetation plots are set up and monitored on a five year interval. Only three target regions in North America have been completed to date, one in Glacier National Park, Montana, and the other two in the Sierra Nevada and White Mountains, California. The four GLORIA summit plots in Glacier National Park were completed over the summers of 2003 and 2004. Because the Continental Divide bisects Glacier National Park (north to south), we chose summits only East of the divide to stay within a similar climatic pattern. Establishing sites was difficult due to the steep and rocky glaciated terrain and the remoteness of suitable sites that required multi-day approaches. Our highest summit (Seward Mtn. 2717 m) is the northernmost and our lowest summit (Dancing Lady Mtn. 2245 m) is southernmost. Treeline is strongly influenced by terrain and is significantly more variable than in the central Rocky Mountains. This also was true of zonal differences of alpine vegetation. Subalpine and even grassland species were found on the same summits as upper alpine species and areas considered subnival. While different zonal areas often occurred on one summit, they were highly influenced by the aspect and slope of that summit area. Between 51 and 82 vascular plants were documented on each summit. There was a high degree of variability in species diversity and percent cover on each summit that was correlated to directional exposure. The summit morphology caused loose vegetative associations, or micro-communities, that varied with exposure, slope angle, and substrate character. Species that exhibited dominance within the target region were Smelowskia calycina var. americana, Polemonium viscosum, Achillea millefolium, Erigeron compositus var. glabratus, and Potentilla fruticosa L. These species reflected the same variability in percent cover on the four sides of the summit areas as did the vegetation as a whole, but were present on all sides.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.V23E0525M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.V23E0525M"><span>Understanding the eruption mechanisms of the explosive Bellecombe Eruptions on Piton de la Fournaise, La Réunion</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Morgan, K.; Ort, M. H.; Di Muro, A.; Parnell, R. A.; Huff, W. D.</p> <p>2017-12-01</p> <p>Piton de la Fournaise (PdF) is an active basaltic volcano on La Réunion island. The Bellecombe Tephra was deposited from at least three unusually explosive eruptions between 3000-5000 ka. The Bellecombe eruptions were interpreted recently to have been due to rapid depressurization of the hydrothermal system when a deep fracture opened after lateral, seaward-directed sliding of the eastern flank, late in a large effusive eruption. This project tests this hypothesis by physically, mineralogically, and chemically characterizing the Bellecombe Tephra to look for evidence of the involvement of the PdF hydrothermal system in the eruptions and understand where the eruptions initiated. The Bellecombe tephra consists of three units separated by incipient soils. Both the Upper and Lower Bellecombe deposits are mostly medium to very fine ash. Lower Bellecombe deposits, from the first two eruptions, are mostly beds of glassy ash containing minor lithic grains and olivine crystals. Hydrothermal minerals, mostly smectite, are present in a few Lower Bellecombe beds. Since these minerals are only present in some beds, the smectite formed before deposition rather than as a product of surficial alteration. The Upper Bellecombe deposits record a third eruption and vary between clast-supported crystal- and lithic-rich lapilli beds and ash beds with abundant ash pellets. The crystals are mostly olivine, with lesser pyroxene and plagioclase and sparse hydrothermal quartz. Gabbro and oceanite clasts are abundant and trachytic pumice rare in these deposits. Hydrothermal minerals are common in most Upper Bellecombe beds. The presence of smectite in some of the Lower Bellecombe beds suggests these deposits came from a system below 200 ºC. Clays in the Upper Bellecombe beds - smectite and mixed layer R0 illite/smectite - imply a system at 40-140 ºC. The hydrothermal system was involved, but might not have been the primary impetus for these eruptions, since hydrothermal minerals are not present in all of the beds, but we find no evidence of high temperatures. The lower Bellecombe vent was near the active summit whereas the Upper Bellecombe vent was from a previously more active area, and this may be reflected in the temperatures of the hydrothermal system. The abundant olivine crystals confirm a relation to a large effusive oceanite eruption.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss024e012425.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss024e012425.html"><span>Earth Observations</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2010-08-22</p> <p>ISS024-E-012425 (22 Aug. 2010) --- This photograph, featuring a landscape in the central Andes mountains near the Chile/Argentina border dominated by numerous volcanoes and associated landforms, was photographed by an Expedition 24 crew member on the International Space Station. Layers of older sedimentary rocks are visible to the southeast (upper right). Many of the volcanic cones show grooves eroded by water to form gullies. Such erosion has occurred since the host volcano was built up, indicating that most volcanoes in this view have been inactive for centuries or millennia. A few volcanoes exhibit much less erosion, and even show tongues of recent, dark lava flows (top left). According to scientists, two of these volcanoes, Cerro el Condor and Peinado have likely erupted within approximately the last 12,000 years (the Holocene Epoch). Also visible in the image is the world’s highest active volcano, Nevado Ojos del Salado, with a summit at 6,887 meters above sea level. The most recent confirmed eruption of this volcano has been dated to 700 (approximately 300 years), but minor eruptive activity may have occurred as recently as 1993. Stratovolcanoes such as Cerro el Condor, Peinado, and Nevado Ojos del Salado are formed partly by buildup of lava flows and partly by buildup of explosively vented material dropping back down onto the surface. One type of material associated with explosive eruptions is welded tuff, which is formed by molten and fragmented rock that accumulates on the ground and later solidifies. A large tuff sheet is visible at top left. Formed very rapidly, these sheets have been termed “instant landscapes.” So active has the Andean volcanic system been that the origin of many of the tuffs in the Andes cannot be pinpointed since source vents have been overprinted by subsequent volcanic events. The volcanic landscape also shows that the erosive work of rivers—and glaciers repeatedly in the recent past—is slower than the opposite processes of the upward building of the volcanoes. The bright blue, nearly 7-kilometer-long lake near the center of the image is known as Laguna Verde. This and other less obvious lakes indicate that water (snowmelt or direct precipitation) is unable to reach the sea, but is rather impounded in the depressions between the volcanic edifices.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFM.V31A0949O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFM.V31A0949O"><span>Diffuse Carbon Dioxide Degassing Monitoring at Santa Ana-Izalco-Coatepeque Volcanic System, El Salvador, Central America</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Olmos, R.; Barahona, F.; Cartagena, R.; Soriano, T.; Salazar, J.; Hernandez, P.; Perez, N.; Notsu, K.; Lopez, D.</p> <p>2001-12-01</p> <p>Santa Ana volcanic complex (0.22 Ma), located 40 Km west of San Salvador, comprises Santa Ana, Izalco, and Cerro Verde stratovolcanoes, the Coatepeque collapse caldera, as well as several cinder cones and explosion craters. Most recent activity has occurred at Izalco (1966) and Santa Ana which shows a permanent acidic crater lake with an intense fumarolic activity. In addition, Santa Ana exhibits a SO2-rich rising plume though no local seismicity has been reported. Weak fumarolic activity is also present at two locations within the Santa Ana volcanic complex: the summit crater of Izalco and Cerro Pacho at Coatepeque caldera. Other important structural features of this volcanic complex are two fault/fissure systems running NNW-SSE that can be identified by the alignment of the stratovolcanoes and numerous cinder cones and explosion craters. In January 2001, a 7.6 magnitude earthquake occurred about 150 Km SE of Santa Ana volcano. A soil gas and CO2 efflux survey was performed to evaluate the impact of this seismic event upon the diffuse degassing rates in Santa Ana volcanic complex in March 2001. A total of 450 soil gas and diffuse CO2 efflux measurements were carried out covering an area of 209.5 Km2. CO2 efflux ranged from non-detectable values to 293 gm-2d-1, with a median of 8.9 gm-2d-1 and an upper quartile of 5.2 gm-2d-1. The CO2 efflux spatial distribution reveals the existence of areas with CO2 efflux higher than 60 gm-2d-1 associated to the fault/fissure systems of NNW-SSE orientation. One of these areas, Cerro Pacho, was selected for the continuous monitoring of diffuse CO2 efflux in late May 2001. Secular variations of diffuse CO2 efflux ranged from 27.4 to 329 gm-2d-1 with a median of 130 gm-2d-1 and a quartile range of 59.3 gm-2d-1. An increasing trend of 43 gm-2d-1 was observed between May and August 2001 overlapped to high-frequency minor fluctuations related to meteorological variables' changes. However, a larger observation time-span is needed to understand the influence of the rainy-season and meteorological parameters in the observed CO2 efflux time series.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=sampling+AND+Miner&id=ED454345','ERIC'); return false;" href="https://eric.ed.gov/?q=sampling+AND+Miner&id=ED454345"><span>Reading the World: Redefining Literature and History Curriculum. A Report from the Multicultural Education Summit Convened by the San Francisco Unified School District. Proceedings (San Francisco, California, March 1998).</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Sandler, Susan; Maxton, Ashindi</p> <p></p> <p>This report documents a 1998 summit that brought together academics and practitioners to discuss the challenges of multicultural education. Part 1, "Summit Proceedings," examines definitions, major topics, voices of the summit, recommendations, and the future. Part 2, "Selected Articles," includes three sections that offer…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/321201','DOE-PATENT-XML'); return false;" href="https://www.osti.gov/biblio/321201"><span>Non-focusing active warhead</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Hornig, H.C.</p> <p>1998-12-22</p> <p>A non-nuclear, non-focusing, active warhead that comprises a high explosive charge contained within a casing of reactive metal is disclosed. When the high explosive is detonated, the reactive metal is dispersed and reacts with the air, which significantly increases the explosive yield of the warhead. The active warhead produces therefore much higher blast effects with significantly reduced weight compared to conventional munitions. The warhead is highly effective against such targets as aircraft which typically have thin fuselages, for example. The explosiveness of this warhead can be enhanced further by elevating the temperature and therefore the reactivity of the reactive metal before or during the explosion. New methods of enhancing the reactivity of the metal are also taught. 4 figs.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/872058','DOE-PATENT-XML'); return false;" href="https://www.osti.gov/servlets/purl/872058"><span>Non-focusing active warhead</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Hornig, Howard C.</p> <p>1998-01-01</p> <p>A non-nuclear, non-focusing, active warhead that comprises a high explosive charge contained within a casing of reactive metal. When the high explosive is detonated, the reactive metal is dispersed and reacts with the air, which significantly increases the explosive yield of the warhead. The active warhead produces therefore much higher blast effects with significantly reduced weight compared to conventional munitions. The warhead is highly effective against such targets as aircraft which typically have thin fuselages, for example. The explosiveness of this warhead can be enhanced further by elevating the temperature and therefore the reactivity of the reactive metal before or during the explosion. New methods of enhancing the reactivity of the metal are also taught.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.V23A0464M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.V23A0464M"><span>Geodetic Observations Using GNSS, Tiltmeter, and DInSAR, at Tokachi-dake Volcano, Japan</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miyagi, Y.</p> <p>2017-12-01</p> <p>Tokachi-dake volcano is located in central Hokkaido, Japan. Middle sized eruptions occurred in 1926, 1962, and 1988-1989, and several small phreatic eruptions also occurred in the meanwhile. After the latest eruption in 1988-1989, many volcanic tremor and active seismicity were revealed. Active fumarolic activities from Taisho crater and 62-2 crater have been observed. In recent years, Tokachi-dake volcano has been observed by using several geodetic techniques, including DInSAR, GNSS, tiltmeter, and gravimeter, to detect regional and local signals associated with volcanic activities. Continuous GNSS stations in summit area operated by Geological Survey of Hokkaido and Hokkaido University [Okazaki et al., 2015] and DInSAR observations using ALOS-2 and TerraSAR-X data have revealed long-term small deformation after 2006 and transient large deformation in May, 2015. We found that these are quite local deformation, because regional GNSS and tiltmeter network did not detect any obvious signals in same period. The remarkable deformation detected by GNSS and DInSAR in the summit area between May and July, 2015, indicates that horizontal displacements are larger than vertical displacements, and westward displacement are much larger than eastward displacement. First, we try to model the deformation pattern using a simple spherical source model [Mogi, 1958] and a dike source model [Okada, 1985]. However, they cannot explain observed deformation because they do not take into consideration a topographic effect in the deformation area. Kawguchi & Miyagi [2016] tried to model the deformation using a boundary element method considering the topographic effect. Consequently, a deformation source which is vertically prolate spheroid beneath the summit shows a better fit between observed and simulated deformation. Annual campaign gravity observations have carried out by several Japanese university and institutes since 2010 [Takahashi et al., 2016]. These reveal that gravity value detected in summit area has decreased more than 0.15mgal up to 2017, which is larger than the gravity value expected from vertical displacements [Okazaki et al., 2017]. In this study, we introduce recent deformation observed by DInSAR, and try to understand the relationship between the deformation and gravity change.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22656656','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22656656"><span>Oximetry fails to predict acute mountain sickness or summit success during a rapid ascent to 5640 meters.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wagner, Dale R; Knott, Jonathan R; Fry, Jack P</p> <p>2012-06-01</p> <p>The purpose of this study was to determine whether arterial oxygen saturation (Spo(2)) and heart rate (HR), as measured by a finger pulse oximeter on rapid arrival to 4260 m, could be predictive of acute mountain sickness (AMS) or summit success on a climb to 5640 m. Climbers (35.0 ± 10.1 years; 51 men, 5 women) were transported from 2650 m to the Piedra Grande hut at 4260 m on Pico de Orizaba within 2 hours. After a median time of 10 hours at the hut, they climbed toward the summit (5640 m) and returned, with a median trip time of 14 hours. The Lake Louise Self-Assessment Scale (LLSS) for AMS, HR, and Spo(2) were collected on arrival at the hut and repeated immediately before and after the climbers' summit attempts. Average Spo(2) for all participants at 4260 m before their departure for the summit was 84.4% ± 3.7%. Thirty-seven of the 56 participants reached the summit, and 59% of all climbers met the criteria for AMS during the ascent. The Spo(2) was not significantly different between those who experienced AMS and those who did not (P = .82); neither was there a difference in Spo(2) between summiteers and nonsummiteers (P = .44). Climbers' HR just before the summit attempt was not related to AMS but was significantly lower for summiteers vs nonsummiteers (P = .04). The Spo(2) does not appear to be predictive of AMS or summit success during rapid ascents. Copyright © 2012 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5132389','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5132389"><span>Summit of the Research Coordination Networks for Undergraduate Biology Education</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Eaton, Carrie Diaz; Allen, Deborah; Anderson, Laurel J.; Bowser, Gillian; Pauley, Mark A.; Williams, Kathy S.; Uno, Gordon E.</p> <p>2016-01-01</p> <p>The first summit of projects funded by the National Science Foundation’s Research Coordination Networks for Undergraduate Biology Education (RCN-UBE) program was held January 14–16, 2016, in Washington, DC. Sixty-five scientists and science educators from 38 of the 41 Incubator and Full RCN-UBE awards discussed the value and contributions of RCNs to the national biology education reform effort. The summit illustrated the progress of this innovative UBE track, first awarded in 2009. Participants shared experiences regarding network development and growth, identified best practices and challenges faced in network management, and discussed work accomplished. We report here on key aspects of network evaluation, characteristics of successful networks, and how to sustain and broaden participation in networks. Evidence from successful networks indicates that 5 years (the length of a Full RCN-UBE) may be insufficient time to produce a cohesive and effective network. While online communication promotes the activities of a network and disseminates effective practices, face-to-face meetings are critical for establishing ties between network participants. Creation of these National Science Foundation–funded networks may be particularly useful for consortia of faculty working to address problems or exchange novel solutions discovered while introducing active-learning methods and/or course-based research into their curricula.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12343708','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12343708"><span>The Earth Summit: a vision shared. An interview with Jean-Claude Faby.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hoeffel, P H</p> <p>1992-01-01</p> <p>Interviewed by Development Forum, the director of UNCED's New York office, Jean-Claude Faby, who has been intimately involved in the negotiations preceding the Earth Summit, discusses his view of the process and expectations of global meeting. Faby explains that during the preparatory process, nongovernmental organizations (NGOs) have played an instrumental role. For example, women have raised issues concerning women, and their efforts are reflected in Agenda 21, the action plan of the Rio Declaration. Although describing the NGOs' critical assessment of the process as a health impatience, Faby notes that the issues to be confronted in Rio are some of the most complicated and vexing environmental and development problems facing the world community. Faby explains that the business community, an important player in the issues at hand, has also taken an active role in the negotiations. Faby acknowledges that the negotiations have witnessed a rift between North and South over the language of the document, a debate that will probably continue during the summit itself. Some of the issues of contention are military spending (a particularly concern of NGOs) and the North's high level of consumption, which the South insists must be addressed. Faby also discusses the issue of implementation and funding following the conclusion of the summit. Although implementation would require some $125 billion (a relatively modest figure), Faby expects that no neat funding package will emerge from Rio. In fact, funding will be one of the primary concerns of the Rio follow-up. Concerning the institutional follow-up of the summit, some are calling for the formation of a new institution, while others oppose such a move.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.V43B2257C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.V43B2257C"><span>One year of real-time radon monitoring at Stromboli volcano and the effect of environmental parameters on 222Rn concentrations</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cigolini, C.; Laiolo, M.; Coppola, D.; Piscopo, D.; Bertolino, S.</p> <p>2009-12-01</p> <p>Real-time radon monitoring at Stromboli volcano has been operative within the last two years. In this contribution we will discuss the recent one-year-long time series analyses in the light of environmental parameters. Two sites for real-time monitoring have been identified by means of a network of periodic radon surveys in order to locate the areas of more efficient response to seismic transients and/or volcanic degassing. Two real-time stations are positioned at Stromboli: one at the summit and located along a fracture zone where the gas flux is concentrated, and the second one at a lower altitude in a sector of diffuse degassing. The signals of the two time-series are essentially concordant but radon concentrations are considerably higher at the summit station. Raw data show that there is a negative correlation between radon emissions and seasonal temperature variations, whereas the correlation with atmospheric pressure is negative for the site of diffuse degassing and sligthly positive for the station lacated along the summit fracture zone. These data and the previously collected ones show that SW winds may substantially decrease radon concentrations at the summit station. Multivarite regression statistics on the radon signals in the light of the above enviromental parameters and tidal forces, may contribute to better idenfify the correlation between radon emissions and variations in volcanic activity. Fig. 1. Radon monitoring stations at Stromboli and the two major summit faults. Stars identify sites for real-time monitoring: LSC and PZZ. The diamond is the location of the automated Labronzo Station. Full dots are stations for periodic measurements using alpha track-etches detectors and E-PERM® electrets. Inset with the location of Stromboli and the major structures of the Aeolian arc.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.V11B2022S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.V11B2022S"><span>Human Footprints in Relation to the 1790 Eruption of Kilauea</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Swanson, D. A.; Rausch, J.</p> <p>2008-12-01</p> <p>In 1790, a party of warriors and their families was decimated by an explosive eruption of Kilauea; fatality estimates range from about 80 to 5,405. In 1920, thousands of footprints made by barefoot walkers in wet accretionary lapilli ash were found within a few kilometers southwest of Kilauea's summit. In 1921, Jaggar related the footprints to survivors or rescuers of the 1790 eruption, mainly because he assumed that few people visited the supposedly forbidden area except in 1790. Archaeologists from Hawai'i Volcanoes National Park recently questioned whether the footprints were made at that time and by warriors, citing a wide range of directions that people were walking and evidence of extensive human use of the area. Forensic and anthropologic studies indicate that a human foot is about 15 percent of an individual's height. A man's foot may be slightly more that 15 percent, a women's slightly less, but nonetheless the height can be estimated to within a few centimeters. We measured the heel-big toe length of more than 400 footprints and calculated an average height of 1.5 m, including some children only a little more than 1 m tall. Few calculated heights are 1.75 m or more. Early Europeans described Hawaiian warriors as tall, one missionary estimating an average height of 1.78 m. A footprint may be larger than a foot, particularly in slippery, wet ash, so our estimates of heights are probably somewhat too large. The data indicate that most of the footprints were made by women and children, not by men, much less warriors. We traced the footprint-bearing ash into the tephra section on the southwest side of Kilauea's caldera. It occurs high in the section, resting on older explosive deposits. Its surface is indented by small lithic lapilli, which fell into the ash while it was still wet; a few even landed in footprints. The lithic lapilli are at the edge of a thick block and lapilli deposit that fell from a high eruption column; the column reached well into the jet stream, because its fallout was mainly dispersed east-southeastward by westerlies, a wind direction found only at high altitudes in Hawai'i. Surges associated with the high eruption column swept over the southwest and west rims of the caldera. These relations indicate that the accretionary lapilli (footprints) ash was an early stage of a powerful eruption involving both high columns and lithic surges. Hawaiian oral tradition says that the 1790 eruption was large, and Jaggar calculated a column height probably greater than 9 km (30,000 ft) based on observations of a pillar (eruption column) seen over Mauna Loa when viewed from the north. This is about halfway through the jet stream. Our work found two deposits of the late 1700s dispersed east of Kilauea's summit. The younger was probably erupted in 1790. A reconstruction of events in 1790 suggests that the accretionary lapilli ash fell early in the eruption, blown southwestward into areas where family groups, mainly women and children, were chipping glass from old pahoehoe for tools. They probably sought shelter while the ash was falling. but once it stopped, they slogged through the mud, leaving footprints in the 2-cm-thick deposit.. Meanwhile, the warriors and their families, camped at Kilauea's summit (supposedly for 3 days) waiting for the eruption to end, saw the sky clear following the ash eruption and started walking southwestward along the west side of the summit area. Then the most powerful stage of the eruption began, sending surges westward across the path of the doomed group, killing many. Afterwards, any survivors or rescuers who walked on the accretionary lapilli ash, by now dry, left no footprints that are preserved.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hpna.advancingexpertcare.org/','NIH-MEDLINEPLUS'); return false;" href="http://hpna.advancingexpertcare.org/"><span>Hospice and Palliative Nurses Association</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p>... Press Release Patients & Families About Serious Illness Certified Nurses are Everywhere Advocacy Palliative Nursing Summit Recent Activity ... Principles State Ambassadors Advocacy Resources Healthcare Resources Certified Nurses Day Certified Nurses are Everywhere Certification is Transformational ...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.epa.gov/pfas/pfas-national-leadership-summit-materials','PESTICIDES'); return false;" href="https://www.epa.gov/pfas/pfas-national-leadership-summit-materials"><span>PFAS National Leadership Summit Materials</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.epa.gov/pesticides/search.htm">EPA Pesticide Factsheets</a></p> <p></p> <p></p> <p>U.S. Environmental Protection Agency (EPA) will be hosting a National Leadership Summit in Washington, D.C. to take action on Per- and Polyfluoroalkyl Substances (PFAS) in the environment. Below are the meeting materials for the Summit.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=STS066-100-027&hterms=active+volcanoes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dactive%2Bvolcanoes','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=STS066-100-027&hterms=active+volcanoes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dactive%2Bvolcanoes"><span>Sakura-jima volcano in Japan as seen from STS-66 Atlantis</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1994-01-01</p> <p>One of the world's most active volcanoes, Sakura-jima in southern-most Kyushu, Japan, erupts dozens of times a year. Volcanic eruptions are so much a part of of daily life in the city of Kagoshima (across the bay and west of Sakura-jima), that school children wear hard hats to school. This photo provides a nice clear view of Sakura-jima on a quiet day - only a plume of steam rises from the summit crater. The summit region is covered with gray ash from the frequent eruptions, and some of the rivers cutting down the mountain (especially the western drainages) appear to be filled with volcanic debris.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/627516','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/627516"><span>Improved Design of Optical MEMS Using the SUMMiT Fabrication Process</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Michalicek, M.A.; Comtois, J.H.; Barron, C.C.</p> <p></p> <p>This paper describes the design and fabrication of optical Microelectromechanical Systems (MEMS) devices using the Sandia Ultra planar Multilevel MEMS Technology (SUMMiT) fabrication process. This state of the art process, offered by Sandia National Laboratories, provides unique and very advantageous features which make it ideal for optical devices. This enabling process permits the development of micromirror devices with near ideal characteristics which have previously been unrealizable in standard polysilicon processes. This paper describes such characteristics as elevated address electrodes, individual address wiring beneath the device, planarized mirror surfaces, unique post-process metallization, and the best active surface area to date.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-sts066-100-027.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-sts066-100-027.html"><span>Sakura-jima volcano in Japan as seen from STS-66 Atlantis</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>1994-11-14</p> <p>One of the world's most active volcanoes, Sakura-jima in southern-most Kyushu, Japan, erupts dozens of times a year. Volcanic eruptions are so much a part of of daily life in the city of Kagoshima (across the bay and west of Sakura-jima), that school children wear hard hats to school. This photo provides a nice clear view of Sakura-jima on a quiet day - only a plume of steam rises from the summit crater. The summit region is covered with gray ash from the frequent eruptions, and some of the rivers cutting down the mountain (especially the western drainages) appear to be filled with volcanic debris.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.8046S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.8046S"><span>Emission of gas and atmospheric dispersion of SO2 during the December 2013 eruption at San Miguel volcano (El Salvador)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Salerno, Giuseppe G.; Granieri, Domenico; Liuzzo, Marco; La Spina, Alessandro; Giuffrida, Giovanni B.; Caltabiano, Tommaso; Giudice, Gaetano; Gutierrez, Eduardo; Montalvo, Francisco; Burton, Michael; Papale, Paolo</p> <p>2016-04-01</p> <p>San Miguel volcano, also known as Chaparrastique, is a basaltic volcano along the Central American Volcanic Arc (CAVA). Volcanism is induced by the convergence of the Cocos Plate underneath the Caribbean Plate, along a 1200-km arc, extending from Guatemala to Costa Rica and parallel to the Central American Trench. The volcano is located in the eastern part of El Salvador, in proximity to the large communities of San Miguel, San Rafael Oriente, and San Jorge. Approximately 70,000 residents, mostly farmers, live around the crater and the city of San Miguel, the second largest city of El Salvador, ten km from the summit, has a population of ~180,000 inhabitants. The Pan-American and Coastal highways cross the north and south flanks of the volcano.San Miguel volcano has produced modest eruptions, with at least 28 VEI 1-2 events between 1699 and 1967 (datafrom Smithsonian Institution http://www.volcano.si.edu/volcano.cfm?vn=343100). It is characterized by visible milddegassing from a summit vent and fumarole field, and by intermittent lava flows and Strombolian activity. Since the last vigorous fire fountaining of 1976, San Miguel has only experienced small steam explosions and gas emissions, minor ash fall and rock avalanches. On 29 December 2013 the volcano erupted producing an eruption that has been classified as VEI 2. While eruptions tend to be low-VEI, the presence of major routes and the dense population in the surrounding of the volcano increases the risk that weak explosions with gas and/or ash emission may pose. In this study, we present the first inventory of SO2, CO2, HCl, and HF emission rates on San Miguel volcano, and an analysis of the hazard from volcanogenic SO2 discharged before, during, and after the December 2013 eruption. SO2 was chosen as it is amongst the most critical volcanogenic pollutants, which may cause acute and chronicle disease to humans. Data were gathered by the geochemical monitoring network managed by the Ministerio de Medio Ambiente y Recursos Naturales (MARN) of El Salvador and by a network of geophysical and geochemical stations established on the volcano by the Italian Istituto Nazionale di Geofisica e Vulcanologia (INGV), immediately after the December 2013 eruption, on the request of MARN. During the eruption, SO2 emissions increased from a background level of ~330 t d-1 to 2200 t d-1, dropping after the eruption to an average level of 680 t d-1. Wind measurements and SO2 fluxes during the pre-, syn- and post-eruptive stages were used to model SO2 dispersion around the volcano. Air SO2 concentration exceeds the dangerous threshold of 5 ppm in the crater region, and in some middle sectors of the highly visited volcanic cone.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2010-01-15/pdf/2010-722.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2010-01-15/pdf/2010-722.pdf"><span>75 FR 2490 - Taking and Importing Marine Mammals; Naval Explosive Ordnance Disposal School Training Operations...</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2010-01-15</p> <p>... Importing Marine Mammals; Naval Explosive Ordnance Disposal School Training Operations Activities at Eglin...) for authorization to take marine mammals, by harassment, incidental to Naval Explosive Ordnance Disposal School (NEODS) training operations, military readiness activities, at Eglin AFB, FL from...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA18507.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA18507.html"><span>Baektu Mountain, China & North Korea</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2014-07-14</p> <p>This image from NASA Terra spacecraft shows Baektu Mountain, an active volcano on the border between North Korea and China. Rising to 2744 m, its summit caldera is filled with a crater lake, Heaven Lake.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5260521','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5260521"><span>Optimizing post activation potentiation for explosive activities in competitive sports</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Gołaś, Artur; Maszczyk, Adam; Mikołajec, Kazimierz; Stastny, Petr</p> <p>2016-01-01</p> <p>Abstract Post activation potentiation (PAP) has shown improved performance during movements requiring large muscular power output following contractions under near maximal load conditions. PAP can be described as an acute enhancement of performance or an enhancement of factors determining an explosive sports activity following a preload stimulus. In practice, PAP has been achieved by complex training, which involves a combination of a heavy loaded exercise followed by a biomechanically similar explosive activity, best if specific for a particular sport discipline. The main objective of this study was to investigate the effects of PAP on performance in explosive motor activities specific for basketball, luge and athletics throws. The novel approach to the experiments included individualized recovery time (IRT) between the conditioning exercise and the explosive activity. Additionally, the research groups were homogenous and included only competitive athletes of similar age and training experience. Thirty one well trained athletes from 3 different sport disciplines participated in the study. All athletes performed a heavy loaded conditioning activity (80-130%1RM) followed by a biomechanically similar explosive exercise, during which power (W) or the rate of power development (W/s/kg) was evaluated. The results of our experiment confirmed the effectiveness of PAP with well-trained athlets during explosive motor activities such as jumping, throwing and pushing. Additionally, our research showed that eccentric supramaximal intensities (130% 1RM) can be effective in eliciting PAP in strength trained athletes. Our experiments also showed that the IRT should be individualized because athletes differ in the strength level, training experience and muscle fiber structure. In the three experiments conducted with basketball players, track and field athletes and luge athletes, the optimal IRT equaled 6 min. This justifies the need to individualize the volume and intensity of the CA, and especially the IRT, between the CA and the explosive activity. PMID:28149397</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70113377','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70113377"><span>Kilauea's 5-9 March 2011 Kamoamoa fissure eruption and its relation to 30+ years of activity from Pu'u 'Ō'ō: Chapter 18</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Orr, Tim R.; Poland, Michael P.; Patrick, Matthew R.; Thelen, Weston A.; Sutton, A.J.; Elias, Tamar; Thornber, Carl R.; Parcheta, Carolyn; Wooten, Kelly M.; Carey, Rebecca; Cayol, Valérie; Poland, Michael P.; Weis, Dominique</p> <p>2015-01-01</p> <p>Lava output from Kīlauea's long-lived East Rift Zone eruption, ongoing since 1983, began waning in 2010 and was coupled with uplift, increased seismicity, and rising lava levels at the volcano's summit and Pu‘u ‘Ō‘ō vent. These changes culminated in the four-day-long Kamoamoa fissure eruption on the East Rift Zone starting on 5 March 2011. About 2.7 × 106 m3 of lava erupted, accompanied by ˜15 cm of summit subsidence, draining of Kīlauea's summit lava lake, a 113 m drop of Pu‘u ‘Ō‘ō's crater floor, ˜3 m of East Rift Zone widening, and eruptive SO2 emissions averaging 8500 tonnes/day. Lava effusion resumed at Pu‘u ‘Ō‘ō shortly after the Kamoamoa eruption ended, marking the onset of a new period of East Rift Zone activity. Multiparameter monitoring before and during the Kamoamoa eruption suggests that it was driven by an imbalance between magma supplied to and erupted from Kīlauea's East Rift Zone and that eruptive output is affected by changes in the geometry of the rift zone plumbing system. These results imply that intrusions and eruptive changes during ongoing activity at Kīlauea may be anticipated from the geophysical, geological, and geochemical manifestations of magma supply and magma plumbing system geometry.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22955322','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22955322"><span>Stress-induced activation of decomposition of organic explosives: a simple way to understand.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Chaoyang</p> <p>2013-01-01</p> <p>We provide a very simply way to understand the stress-induced activation of decomposition of organic explosives by taking the simplest explosive molecule nitromethane (NM) as a prototype and constraining one or two NM molecules in a shell to represent the condensed phrase of NM against the stress caused by tension and compression, sliding and rotational shear, and imperfection. The results show that the stress loaded on NM molecule can always reduce the barriers of its decomposition. We think the origin of this stress-induced activation is due to the increased repulsive intra- and/or inter- molecular interaction potentials in explosives resulted from the stress, whose release is positive to accelerate the decomposition. Besides, by these models, we can understand that the explosives in gaseous state are easier to analyze than those in condensed state and the voids in condensed explosives make them more sensitive to external stimuli relative to the perfect crystals.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://rosap.ntl.bts.gov/view/dot/24551','DOTNTL'); return false;" href="https://rosap.ntl.bts.gov/view/dot/24551"><span>Preparing tomorrow's transportation workforce : a Midwest summit.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntlsearch.bts.gov/tris/index.do">DOT National Transportation Integrated Search</a></p> <p></p> <p>2010-08-01</p> <p>Preparing Tomorrows Transportation Workforce: A Midwest Summit, held April 2728, 2010, in Ames, Iowa, was one of several : regional transportation workforce development summits held across the United States in 2009 and 2010 as part of a coordin...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.nrel.gov/news/program/2018/nrel-wind-leaders-participate-in-wind-industry-partnership-summit.html','SCIGOVWS'); return false;" href="https://www.nrel.gov/news/program/2018/nrel-wind-leaders-participate-in-wind-industry-partnership-summit.html"><span>NREL Wind Leaders Participate in Wind Industry Partnership Summit | News |</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.science.gov/aboutsearch.html">Science.gov Websites</a></p> <p></p> <p></p> <p>NREL</A> NREL Wind <em>Leaders</em> Participate in Wind Industry Partnership Summit NREL Wind <em>Leaders</em> enable innovations needed to advance U.S. wind systems. "The summit brought together <em>leaders</em> from</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://rosap.ntl.bts.gov/view/dot/24791','DOTNTL'); return false;" href="https://rosap.ntl.bts.gov/view/dot/24791"><span>2009 National Safety Performance Function Summit</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntlsearch.bts.gov/tris/index.do">DOT National Transportation Integrated Search</a></p> <p></p> <p>2010-07-01</p> <p>The Illinois Department of Transportation (IDOT) and the Illinois Center for Transportation (ICT) sponsored and : hosted the first National Safety Performance Function Summit on July 29 and 30, 2009, in Chicago, Illinois. The : goal of this summit wa...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70146876','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70146876"><span>Continuous monitoring of Hawaiian volcanoes with thermal cameras</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Patrick, Matthew R.; Orr, Tim R.; Antolik, Loren; Lee, Robert Lopaka; Kamibayashi, Kevan P.</p> <p>2014-01-01</p> <p>Continuously operating thermal cameras are becoming more common around the world for volcano monitoring, and offer distinct advantages over conventional visual webcams for observing volcanic activity. Thermal cameras can sometimes “see” through volcanic fume that obscures views to visual webcams and the naked eye, and often provide a much clearer view of the extent of high temperature areas and activity levels. We describe a thermal camera network recently installed by the Hawaiian Volcano Observatory to monitor Kīlauea’s summit and east rift zone eruptions (at Halema‘uma‘u and Pu‘u ‘Ō‘ō craters, respectively) and to keep watch on Mauna Loa’s summit caldera. The cameras are long-wave, temperature-calibrated models protected in custom enclosures, and often positioned on crater rims close to active vents. Images are transmitted back to the observatory in real-time, and numerous Matlab scripts manage the data and provide automated analyses and alarms. The cameras have greatly improved HVO’s observations of surface eruptive activity, which includes highly dynamic lava lake activity at Halema‘uma‘u, major disruptions to Pu‘u ‘Ō‘ō crater and several fissure eruptions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED395420.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED395420.pdf"><span>National Council on Disability. Annual Report, Volume 15. Fiscal Year 1994.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>National Council on Disability, Washington, DC.</p> <p></p> <p>This annual report describes major activities of the National Council on Disability (NCD) for Fiscal Year 1994. Activities included: conducted a summit meeting on the Americans with Disabilities Act (ADA); held health care reform town meetings; communicated with the Health Care Financing Administration concerning reimbursement of medical…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.V31E2577T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.V31E2577T"><span>Conduit Wall Failure as a Trigger for Transition From Strombolian to Phreatomagmatic Explosive Activity in the Cova de Paúl Crater Eruption on Santo Antão, Cape Verde Islands</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tarff, R. W.; Day, S. J.</p> <p>2011-12-01</p> <p>Episodes of hazardous phreatomagmatic explosive activity, including Surtseyan activity, occur within otherwise less dangerous effusive to mildly explosive magmatic eruptions at high-elevation vents on many oceanic island volcanoes. The water driving these explosions is sourced from freshwater aquifers within the volcanic edifices. Understanding volcanic and geophysical precursors to, and mechanisms of, the (frequently abrupt) transitions to explosive activity is required as a basis for effective warning and mitigation of the resulting hazards. Here we describe near-vent deposits around the large Cova de Paúl crater on the island of Santo Antão, Cape Verde Islands, which provide some insights into a transition from mild magmatic to violently explosive phreatomagmatic activity in one such eruption. This pre-historic but well-preserved crater formed in a single eruption that produced extensive low-temperature, lithic-rich phreatomagmatic pyroclastic flows and surge deposits; these are interbedded in proximal outcrops with airfall breccia and ash beds containing varying proportions of lithic and juvenile clasts, pointing to a series of climactic explosions within an extended period of milder explosive activity of broadly Surtseyan type. Prior to the transition to phreatomagmatic activity, the eruption had been characterized by mild Strombolian activity that produced scoria and spatter deposits of broadly tephritic composition. The Strombolian deposits contain a distinct population of strongly banded, low-vesicularity angular clasts with strongly prolate vesicles and a notably glassy appearance. These became markedly larger and more abundant just below the transition to the phreatomagmatic deposits. Comparisons of these clasts with the Strombolian scoria suggest that they are fragments of flow-banded chilled margins from the walls of the eruptive conduit. Thermal shattering of these margins to produce the angular glassy clasts may record the onset of groundwater flow into the conduit, leading to the phreatomagmatic explosive phase of the eruption. Fragmentation of the conduit wall and ingress of groundwater would likely have been accompanied by seismic swarms consisting of high-frequency fracture events and episodes of harmonic tremor, pointing to a potential geophysical signature of the onset of phreatomagmatic explosive activity in comparable future eruptions on Santo Antão and other oceanic islands.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://rosap.ntl.bts.gov/view/dot/15422','DOTNTL'); return false;" href="https://rosap.ntl.bts.gov/view/dot/15422"><span>Proceedings of Bus Summit 2000 : ensuring a healthy U.S. bus industry</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntlsearch.bts.gov/tris/index.do">DOT National Transportation Integrated Search</a></p> <p></p> <p>2000-10-01</p> <p>The Federal Transit Administration (FTA) Bus Industry Summit was held October 18-19, 2000, in Washington, DC. The Summit offered an opportunity for representatives from the transit industry, including transit providers, vehicle manufacturers, consult...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.loc.gov/pictures/collection/hh/item/wa0598.photos.370931p/','SCIGOV-HHH'); return false;" href="https://www.loc.gov/pictures/collection/hh/item/wa0598.photos.370931p/"><span>1. Context view shows approach of access road to summit, ...</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>1. Context view shows approach of access road to summit, communication towers and NW corner of lookout tower at center right. Camera is pointed SE. - Chelan Butte Lookout, Summit of Chelan Butte, Chelan, Chelan County, WA</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.V13C0398G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.V13C0398G"><span>The First Historical Eruption of Kambalny Volcano in 2017 .</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gordeev, E.</p> <p>2017-12-01</p> <p>The first historical eruption at Kambalny volcano began about 21:20 UTC on March 24, 2017 with powerful ash emissions up to 6 km above sea level from the pre-summit crater. According to tephrochronological data, it is assumed that the strong eruptions of the volcano occurred 200 (?) and 600 years ago. KVERT (Kamchatka Volcanic Eruption Response Team) of the Institute of Volcanology and Seismology FEB RAS has been monitoring Kambalny volcano since 2002. KVERT worked closely with AMC Elizovo and Tokyo VAAC during the eruption at Kambalny volcano in 2017. The maximum intensity of ash emissions occurred on 25-26 March: a continuous plume laden with ash particles spread over several thousand kilometers, changing the direction of propagation from the volcano from the south-west to the south and south-east. On 27-29 March, the ash plume extended to the west, on 30 March - to the southeast of the volcano. On March 31 and April 01, the volcano was relatively quiet. The resumption of the volcano activity after two days of rest was expressed in powerful ash emissions up to 7 km above sea level. Gas-steam plumes containing some amount of ash were noted on 02-05 April, and powerful ash emissions up to 7 km above sea level occurred on 09 April. The explosive activity at the volcano ended on 11 April. The area of ash deposits was about 1500 km2, the total area covered by ash falls, for example, on 25 March, was about 650 thousand km2. To monitor and study the Kambalny volcano eruption we mainly used satellite images of medium resolution available in the information system "Monitoring volcanic activity in Kamchatka and Kurile Islands" (VolSatView). This work was supported by the Russian Science Foundation, project No. 16-17-00042.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007BVol...69..741C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007BVol...69..741C"><span>Pits, rifts and slumps: the summit structure of Piton de la Fournaise</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carter, Adam; van Wyk de Vries, Benjamin; Kelfoun, Karim; Bachèlery, Patrick; Briole, Pierre</p> <p>2007-06-01</p> <p>A clear model of structures and associated stress fields of a volcano can provide a framework in which to study and monitor activity. We propose a volcano-tectonic model for the dynamics of the summit of Piton de la Fournaise (La Reunion Island, Indian Ocean). The summit contains two main pit crater structures (Dolomieu and Bory), two active rift zones, and a slumping eastern sector, all of which contribute to the actual fracture system. Dolomieu has developed over 100 years by sudden large collapse events and subsequent smaller drops that include terrace formation. Small intra-pit collapse scars and eruptive fissures are located along the southern floor of Dolomieu. The western pit wall of Dolomieu has a superficial inward dipping normal fault boundary connected to a deeper ring fault system. Outside Dolomieu, an oval extension zone containing sub-parallel pit-related fractures extends to a maximum distance of 225 m from the pit. At the summit the main trend for eruptive fissures is N80°, normal to the north south rift zone. The terraced structure of Dolomieu has been reproduced by analogue models with a roof to width ratio of approximately 1, suggesting an original magma chamber depth of about 1 km. Such a chamber may continue to act as a storage location today. The east flank has a convex concave profile and is bounded by strike-slip fractures that define a gravity slump. This zone is bound to the north by strike-slip fractures that may delineate a shear zone. The southern reciprocal shear zone is probably marked by an alignment of large scoria cones and is hidden by recent aa lavas. The slump head intersects Dolomieu pit and may slide on a hydrothermally altered layer known to be located at a depth of around 300 m. Our model has the summit activity controlled by the pit crater collapse structure, not the rifts. The rifts become important on the mid-flanks of the cone, away from pit-related fractures. On the east flank the superficial structures are controlled by the slump. We suggest that during pit subsidence intra-pit eruptions may occur. During tumescence, however, the pit system may become blocked and a flank eruption is more likely. Intrusions along the rift may cause deformation that subsequently increases the slump’s potential to deform. Conversely, slumping may influence the east flank stress distribution and locally control intrusion direction. These predictions can be tested with monitoring data to validate the model and, eventually, improve monitoring.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70017649','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70017649"><span>Evaluation of sulfur dioxide emissions from explosive volcanism: the 1982-1983 eruptions of Galunggung, Java, Indonesia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bluth, G.J.S.; Casadevall, T.J.; Schnetzler, C.C.; Doiron, S.D.; Walter, Louis S.; Krueger, A.J.; Badruddin, M.</p> <p>1994-01-01</p> <p>Galunggung volcano, Java, awoke from a 63-year quiescence in April 1982, and erupted sporadically through January 1983. During its most violent period from April to October, the Cikasasah Volcano Observatory reported 32 large and 56 moderate to small eruptions. From April 5 through September 19 the Total Ozone Mapping Spectrometer (TOMS), carried on NASA's Nimbus-7 satellite, detected and measured 24 different sulfur dioxide clouds; an estimated 1730 kilotons (kt) of SO2 were outgassed by these explosive eruptions. The trajectories, and rapid dispersion rates, of the SO2 clouds were consistent with injection altitudes below the tropopause. An additional 300 kt of SO2 were estimated to have come from 64 smaller explosive eruptions, based on the detection limit of the TOMS instrument. For the first time, an extended period of volcanic activity was monitored by remote sensing techniques which enabled observations of both the entire SO2 clouds produced by large explosive eruptions (using TOMS), and the relatively lower levels of SO2 emissions during non-explosive outgassing (using the Correlation Spectrometer, or COSPEC). Based on COSPEC measurements from August 1982 to January 1983, and on the relationship between explosive and non-explosive degassing, approximately 400 kt of SO2 were emitted during non-explosive activity. The total sulfur dioxide outgassed from Galunggung volcano from April 1982 to January 1983 is calculated to be 2500 kt (?? 30%) from both explosive and non-explosive activity. While Galunggung added large quantities of sulfur dioxide to the atmosphere, its sporadic emissions occurred in relatively small events distributed over several months, and reached relatively low altitudes, and are unlikely to have significantly affected aerosol loading of the stratosphere in 1982 by volcanic activity. ?? 1994.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100021111','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100021111"><span>Atrial Arrhythmia Summit: Post Summit Report</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Barr, Yael</p> <p>2010-01-01</p> <p>The Atrial Arrhythmia Summit brought together nationally and internationally recognized experts in cardiology, electrophysiology, exercise physiology, and space medicine in an effort to elucidate the mechanisms, risk factors, and management of atrial arrhythmias in the unique occupational cohort of the U.S. astronaut corps.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70170360','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70170360"><span>Observations of volcanic tremor during January-February 2005 eruption of Mt. Veniaminof, Alaska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>De Angelis, Slivio; McNutt, Stephen R.</p> <p>2007-01-01</p> <p>Mt. Veniaminof, Alaska Peninsula, is a stratovolcano with a summit ice-filled caldera containing a small intracaldera cone and active vent. From January 2 to February 21, 2005, Mt. Veniaminof erupted. The eruption was characterized by numerous small ash emissions (VEI 0 to 1) and accompanied by low-frequency earthquake activity and volcanic tremor. We have performed spectral analyses of the seismic signals in order to characterize them and to constrain their source. Continuous tremor has durations of minutes to hours with dominant energy in the band 0.5– 4.0 Hz, and spectra characterized by narrow peaks either irregularly (non-harmonic tremor) or regularly spaced (harmonic tremor). The spectra of non-harmonic tremor resemble those of low-frequency events recorded simultaneously with surface ash explosions, suggesting that the source mechanisms might be similar or related. We propose that non-harmonic tremor at Mt. Veniaminof results from the coalescence of gas bubbles while low-frequency events are related to the disruption of large gas pockets within the conduit. Harmonic tremor, characterized by regular and quasisinusoidal waveforms, has duration of hours. Spectra containing up to five harmonics suggest the presence of a resonating source volume that vibrates in a longitudinal acoustic mode. An interesting feature of harmonic tremor is that frequency is observed to change over time; spectral lines move towards higher or lower values while the harmonic nature of the spectra is maintained. Factors controlling the variable characteristics of harmonic tremor include changes in acoustic velocity at the source and variations of the effective size of the resonator.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70033031','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70033031"><span>Summit CO2 emission rates by the CO2/SO2 ratio method at Kīlauea Volcano, Hawaiʻi, during a period of sustained inflation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hager, S.A.; Gerlach, T.M.; Wallace, P.J.</p> <p>2008-01-01</p> <p>The emission rate of carbon dioxide escaping from the summit of Kīlauea Volcano, Hawaiʻi, proved highly variable, averaging 4900 ± 2000 metric tons per day (t/d) in June–July 2003 during a period of summit inflation. These results were obtained by combining over 90 measurements of COSPEC-derived SO2emission rates with synchronous CO2/SO2 ratios of the volcanic gas plume along the summit COSPEC traverse. The results are lower than the CO2 emission rate of 8500 ± 300 t/d measured by the same method in 1995–1999 during a period of long-term summit deflation [Gerlach, T.M., McGee, K.A., Elias, T., Sutton, A.J. and Doukas, M.P., 2002. Carbon dioxide emission rate of Kīlauea Volcano: Implications for primary magma and the summit reservoir. Journal of Geophysical Research-Solid Earth, 107(B9): art. no.-2189.]. Analysis of the data indicates that the emission rates of the present study likely reflect changes in the magma supply rate and residence time in the summit reservoir. It is also likely that emission rates during the inflation period were heavily influenced by SO2 pulses emitted adjacent to the COSPEC traverse, which biased CO2/SO2 ratios towards low values that may be unrepresentative of the global summit gas plume. We conclude that the SO2 pulses are consequences of summit re-inflation under way since 2003 and that CO2 emission rates remain comparable to, but more variable than, those measured prior to re-inflation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.V51H..08S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.V51H..08S"><span>Setting of the Father's Day Eruption at Kilauea</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Swanson, D. A.</p> <p>2007-12-01</p> <p>The Father's Day eruption and associated intrusion took place within a 10-km segment of Kilauea's east rift zone between Hi`iaka and Napau Craters--a segment that has had more numerous eruptions and intrusions than any other of comparable length during the past 200, probably the past 1000, years. Fifteen known eruptions started in this area in the past 200 years: 1840, 1922, 1923, 1962, August and October 1963, March and December 1965, August and October 1968, February and May 1969, May and November 1973, and March 1980 (only 3 cubic meters!). Three others, not previously designated as distinct eruptions despite having all the appropriate characteristics, took place during on-going eruptions: two in `Alo`i Crater in 1970 and 1972, and one in Napau Crater in 1997. Two of the largest shields on the east rift zone formed during long-lasting eruptions within this area--Kane Nui o Hamo at an unknown date, perhaps the 11-12th century, and Mauna Ulu (1969-1974). In addition, many small intrusions without eruptions are known. Seven short eruptions punctuated a prolonged eruption: four within the segment during the Mauna Ulu eruption, two at the summit and southwest rift zone during that same eruption, and one in Napau Crater in 1997 during the Pu`u `O`o eruption. Thus the Father's Day eruption is not unique by virtue of taking place during an ongoing eruption elsewhere along the rift zone. The increased frequency of activity in the segment during the 20th century is obvious, particularly after 1962. For most of the past 1,000 years, eruptions were centered at Kilauea's summit, with significant but lesser activity along the rift zones. A large summit deflation in 1924 ended the nearly continuous lava lake in Halemaumau, eventually leading to the past 5 decades of dominantly east rift zone activity. This segment of the rift zone contains most of the pit craters on Kilauea and gradually changes from a SE trend near the caldera to an ENE trend that characterizes the rest of the zone. The Koa`e fault system joins the east rift zone at the curve. The complex structural setting likely affects the frequency of magmatic activity in the segment. All of the eruptive and intrusive activity results in storage of isolated magma bodies. Not surprisingly, petrologists find evidence that summit magma mixes with stored, fractionated magma. The area near Makaopuhi Crater and Kane Nui o Hamo is a particular focus, inferred since the mid-1960s to harbor a shallow magma reservoir. All of the eruptions and intrusions are accompanied by sharp deflation and shallow seismicity at the summit and shallow seismicity and uplift along the intrusion or eruptive fissures. Most often, no seismicity occurs between the summit and the area of intrusion or eruption. Within that area, seismicity commonly migrates downrift but occasionally uprift. Similarly, crack opening generally progresses downrift, with a few exceptions. Cracks generally trend about 65 degrees and can be either left- or right-stepping. Cracks open along azimuths of 155-175, with local exceptions. There is no structural difference between eruptive cracks (fissures) and non- eruptive cracks. Single eruptive fissures rarely exceed 200 m in length, instead stepping within en echelon zones above a presumably linear dike. Since the late 1960s, widening has been measured across the active area during eruptions and intrusions, first by EDM and then by satellite-based systems. The opening is nearly symmetrical within the rift zone, but farther out the north flank barely responds whereas the south flank moves seaward. Available leveling data show uplift on either side of the dike and subsidence along the crest. Examples of deformation in the 1960s and 1970s will be presented, and bibliographic references to past activity will be available.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1980IJBm...24..157E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1980IJBm...24..157E"><span>Determinants of heat production in newborn lambs</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eales, F. A.; Small, J.</p> <p>1980-06-01</p> <p>Measurement of summit metabolism (the maximum rate of heat production) in lambs aged 1 or 4h revealed considerable between animal variation. Summit metabolism per unit body weight decreased as body weight increased whereas summit metabolism per unit body surface area was independent of body weight. Severe pre-partum hypoxia was apparently associated with a low summit metabolism at 1 or 4h of age which made such lambs very susceptible to hypothermia. This deficiency in heat production capacity did not appear to be a permanent featuresince most lambs so affected recovered full thermoregulatory ability by 12h of age. Feeding of colostrum conferred an immediate 18% increase in summit metabolism. The significance of these findings to the prevention of hypothermia in the newborn lamb is discussed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17465158','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17465158"><span>Summit-to-sea mapping and change detection using satellite imagery: tools for conservation and management of coral reefs.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shapiro, A C; Rohmann, S O</p> <p>2005-05-01</p> <p>Continuous summit-to-sea maps showing both land features and shallow-water coral reefs have been completed in Puerto Rico and the U.S. Virgin Islands, using circa 2000 Landsat 7 Enhanced Thematic Mapper (ETM+) Imagery. Continuous land/sea terrain was mapped by merging Digital Elevation Models (DEM) with satellite-derived bathymetry. Benthic habitat characterizations were created by unsupervised classifications of Landsat imagery clustered using field data, and produced maps with an estimated overall accuracy of>75% (Tau coefficient >0.65). These were merged with Geocover-LC (land use/land cover) data to create continuous land/ sea cover maps. Image pairs from different dates were analyzed using Principle Components Analysis (PCA) in order to detect areas of change in the marine environment over two different time intervals: 2000 to 2001, and 1991 to 2003. This activity demonstrates the capabilities of Landsat imagery to produce continuous summit-to-sea maps, as well as detect certain changes in the shallow-water marine environment, providing a valuable tool for efficient coastal zone monitoring and effective management and conservation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995GMS....92..199M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995GMS....92..199M"><span>Recent inflation and flank movement of Mauna Loa Volcano</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miklius, Asta; Lisowski, Michael; Delaney, Paul T.; Denlinger, Roger P.; Dvorak, John J.; Okamura, Arnold T.; Sakol, Maurice K.</p> <p></p> <p>Geodetic measurements on the summit of Mauna Loa reveal that since the last eruption in 1984, the shallow summit magma chamber has inflated approximately the same amount as between the 1975 and 1984 eruptions. However, it does not appear to have recovered the entire volume withdrawn during the 1984 eruption. Together with the lack of increased shallow earthquake activity, this observation suggests that, as of June 1995, the next eruption of Mauna Loa is not yet imminent. Global Positioning System measurements in 1993 and 1994 show southeastward movement of the southeast flank of over 4 cm/year, comparable to displacements measured on adjacent Kilauea Volcano's south flank over the same interval. The upper west flank appears to be stable, producing a strong asymmetry of motion about the summit. Gradients of motion on the southeast flank result in about one microstrain/year of compression and shear across the Kaoiki seismic zone, an area of persistent seismicity that has produced large historic earthquakes. The flank motions observed between 1993 and 1994 could be caused by the combined effects of slip along the basal Kaoiki decollement and inflation of a deep source.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFM.V21E..02H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFM.V21E..02H"><span>Understanding the dynamics of magmatic systems - evidence from Long Valley Caldera and Kilauea Volcano</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hill, D. P.; Swanson, D. A.</p> <p>2001-12-01</p> <p>Active magmatic processes produce a wide range of signals that are capable of detection at the Earth's surface by modern geophysical and geochemical instrumentation. The most robust of these signals include spatial-temporal patterns of (1) ground deformation spanning a broad spectrum from gradual secular and quasi-static changes to the high-frequency vibrations associated with seismic waves generated by local, brittle-failure earthquakes and (2) magmatic gas emissions of, most notably, SO2 and CO2. The long records of deformation (in this broad sense) and geochemical data accumulated for Kilauea Volcano on the Island of Hawai`i and in Long Valley Caldera in eastern California exemplify the value of spatially and temporally dense monitoring as a basis for understanding the dynamics of magmatic systems. Kilauea's magma conduit, defined by brittle failure and LP earthquakes, has the form of a narrow, straw-like structure extending from within the lithosphere at a depth of >40 km to a magma chamber centered roughly 5 km beneath the summit crater (Halemaumau). This shallow magma chamber, which consists of a plexus of dikes and sills, is capable of feeding eruptions both within the summit caldera and along the east and southwest rift zones. The current eruption from vents along the east rift zone, which began 18 years ago, appears to be gradually draining this summit magma chamber, as Kilauea's summit has been subsiding about 10 cm/yr since the eruption began. This is equivalent to a volume of about 0.01 km3/yr, 10 percent of the eruption rate of 0.1 km3/yr. Most of the gas released by the magma column escapes through the summit caldera as it ascends from the magma chamber toward the summit and thence through conduits to the active vents on the east rift zone. Indeed, the CO2 flux (about 10,000 tones/yr) from the caldera serves as a proxy for magma flux through the conduit system. Dynamic interaction of the active magma conduit with the hydrothermal system beneath the summit crater produces sequences of shallow LP and VLP earthquakes. Two magmatic systems contribute to the 20 years of unrest in Long Valley Caldera: one beneath the resurgent dome in the center of the caldera and the other beneath Mammoth Mountain on the southwest rim of the caldera. Cumulative uplift of the resurgent dome by 80 cm reflects a volume increase of roughly 0.3 km3 in magma to chamber centered at a depth of 7 to 10 km beneath the surface. Recurring swarms of brittle-failure earthquakes in the south moat follow increased inflation rates with the more energetic episodes associated with intrusions of magma or magmatic brine into the brittle crust. The absence of seismicity at depths greater than 10 km beneath the caldera, however, leaves a question mark for the nature of this magmatic system at mid- to lower-crustal depths. The absence of magmatic gas emissions in the vicinity of the resurgent dome and south moat suggests that the volatile components of this magmatic system remain trapped below an impermeable seal. In contrast, a dike-like distribution of deep LP earthquakes overlain by a volume of brittle-failure earthquakes, including several shallow VLP earthquakes, delineate the magmatic system beneath Mammoth Mountain from mid-crustal depths of 30 km to within 3 or 4 km of the surface. This system, which became activated with a six-month-long earthquake swarm and intrusion beneath Mammoth Mountain in 1989, has continued to produce a diffuse efflux of magmatic CO2 at a rate of 200 to 300 tones/day apparently fed by basaltic magma distributed in a plexus of dikes and sills at mid-crustal depths.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70011736','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70011736"><span>Storage, migration, and eruption of magma at Kilauea volcano, Hawaii, 1971-1972</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Duffield, W.A.; Christiansen, R.L.; Koyanagi, R.Y.; Peterson, D.W.</p> <p>1982-01-01</p> <p>The magmatic plumbing system of Kilauea Volcano consists of a broad region of magma generation in the upper mantle, a steeply inclined zone through which magma rises to an intravolcano reservoir located about 2 to 6 km beneath the summit of the volcano, and a network of conduits that carry magma from this reservoir to sites of eruption within the caldera and along east and southwest rift zones. The functioning of most parts of this system was illustrated by activity during 1971 and 1972. When a 29-month-long eruption at Mauna Ulu on the east rift zone began to wane in 1971, the summit region of the volcano began to inflate rapidly; apparently, blockage of the feeder conduit to Mauna Ulu diverted a continuing supply of mantle-derived magma to prolonged storage in the summit reservoir. Rapid inflation of the summit area persisted at a nearly constant rate from June 1971 to February 1972, when a conduit to Mauna Ulu was reopened. The cadence of inflation was twice interrupted briefly, first by a 10-hour eruption in Kilauea Caldera on 14 August, and later by an eruption that began in the caldera and migrated 12 km down the southwest rift zone between 24 and 29 September. The 14 August and 24-29 September eruptions added about 107 m3 and 8 ?? 106 m3, respectively, of new lava to the surface of Kilauea. These volumes, combined with the volume increase represented by inflation of the volcanic edifice itself, account for an approximately 6 ?? 106 m3/month rate of growth between June 1971 and January 1972, essentially the same rate at which mantle-derived magma was supplied to Kilauea between 1952 and the end of the Mauna Ulu eruption in 1971. The August and September 1971 lavas are tholeiitic basalts of similar major-element chemical composition. The compositions can be reproduced by mixing various proportions of chemically distinct variants of lava that erupted during the preceding activity at Mauna Ulu. Thus, part of the magma rising from the mantle to feed the Mauna Ulu eruption may have been stored within the summit reservoir from 4 to 20 months before it was erupted in the summit caldera and along the southwest rift zone in August and September. The September 1971 activity was only the fourth eruption on the southwest rift zone during Kilauea's 200 years of recorded history, in contrast to more than 20 eruptions on the east rift zone. Order-of-magnitude differences in topographic and geophysical expression indicate greatly disparate eruption rates for far more than historic time and thus suggest a considerably larger dike swarm within the east rift zone than within the southwest rift zone. Characteristics of the historic eruptions on the southwest rift zone suggest that magma may be fed directly from active lava lakes in Kilauea Caldera or from shallow cupolas at the top of the summit magma reservoir, through fissures that propagate down rift from the caldera itself at the onset of eruption. Moreover, emplacement of this magma into the southwest rift zone may be possible only when compressive stress across the rift is reduced by some unknown critical amount owing either to seaward displacement of the terrane south-southeast of the rift zone or to a deflated condition of Mauna Loa Volcano adjacent to the northwest, or both. The former condition arises when the forceful emplacement of dikes into the east rift zone wedges the south flank of Kilauea seaward. Such controls on the potential for eruption along the southwest rift zone may be related to the topographic and geophysical constrasts between the two rift zones. ?? 1982.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.V43B1790O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.V43B1790O"><span>Long period seismic signals observed before the Caldera formation during the 2000 Miyake- jima volcanic activity</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ohminato, T.; Kobayashi, T.; Ida, Y.; Fujita, E.</p> <p>2006-12-01</p> <p>During the 2000 Miyake-jima volcanic activity started on 26 June 2000, an intense earthquake swarm occurred initially beneath the southwest flank near the summit and gradually migrated west of the island. A volcanic earthquake activity in the island was reactivated beneath the summit, leading to a summit eruption with a significant summit subsidence on 8 July. We detected small but numerous number of long period (LP) seismic signals during these activities. Most of them include both 0.2 and 0.4 Hz components suggesting an existence of a harmonic oscillator. Some of them have dominant frequency peak at 0.2Hz (LP1), while others have one at 0.4 Hz (LP2). At the beginning of each waveform of both LP1 and LP2, an impulsive signal with a pulse-width of about 2 s is clearly identified. The major axis of the particle motion for the initial impulsive signal is almost horizontal suggesting a shallow source beneath the summit, while the inclined particle motion for the latter phase suggests deeper source beneath the island. For both LP1 and LP2, we can identify a clear positive correlation between the amplitude of the initial pulse and that of the latter phase. We conducted waveform inversions for the LP events assuming a point source and determined the locations and mechanisms simultaneously. We assumed three types of source mechanisms; three single forces, six moment tensor components, and a combination of moment tensor and single forces. We used AIC to decide the optimal solutions. Firstly, we applied the method to the entire waveform including both the initial pulse and the latter phase. The source type with a combination of moment tensor and single force components yields the minimum values of the AIC for both LP events. However, the spatial distribution of the residual errors tends to have two local minima. Considering the error distribution and the characteristic particle motions, it is likely that the source of the LP event consists of two different parts. We thus divided the LP events into two parts; the initial and the latter phases, and applied the same waveform inversion procedure separately for each part of the waveform. The inversion results show that the initial impulsive phase and the latter oscillatory phase are well explained by a nearly horizontal single force and a moment solution, respectively. The single force solutions of the initial pulse are positioned at the depth of about 2 km beneath the summit. The single force initially oriented to the north, and then to the south. On the other hand, the sources of the moment solutions are significantly deeper than the single force solutions. The hypocenter of the later phase of LP1 is located at the depth of 5.5 km in the southern region of the island, while that for the LP2 event is at 5.1 km beneath the summit. The horizontal oscillations are relatively dominant for both the LP1 and LP2 events. Although the two sources are separated each other by several kilometers, the positive correlation between the amplitudes of the initial pulse and the latter phase strongly suggests that the shallow sources trigger the deeper sources. The source time histories of the 6 moment tensor components of the latter portion of the LP1 and LP2 are not in phase. This makes it difficult to extract information on source geometry using the amplitude ratio among moment tensor components in a traditional manner. It may suggest that the source is composed of two independent sources whose oscillations are out of phase.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.loc.gov/pictures/collection/hh/item/pa4014.photos.222615p/','SCIGOV-HHH'); return false;" href="https://www.loc.gov/pictures/collection/hh/item/pa4014.photos.222615p/"><span>Detail, external parabolic antenna (later addition). Note how waveguide was ...</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>Detail, external parabolic antenna (later addition). Note how waveguide was cut to remove active portion of antenna. - Western Union Telegraph Company, Jennerstown Relay, Laurel Summit Road off U.S. 30, Laughlintown, Westmoreland County, PA</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA13827.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA13827.html"><span>NASA Spacecraft Captures Fury of Russian Volcano</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2011-01-27</p> <p>This nighttime thermal infrared image from NASA Terra spacecraft shows Shiveluch volcano, one of the largest and most active volcanoes in Russia Kamchatka Peninsula; the bright, hot summit lava dome is evident in the center of the image.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss029e020003.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss029e020003.html"><span>Earth observation taken by the Expedition 29 crew</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2011-10-07</p> <p>ISS029-E-020003 (7 Oct. 2011) --- Parinacota Volcano in the Chile-Bolivia border region, South America is featured in this image photographed by an Expedition 29 crew member on the International Space Station. Volcan Parinacota (?flamingo lake? in the regional Aymara language) is a potentially active stratovolcano located on the Altiplano, a high plateau situated within the Andes Mountains of west-central South America. While no direct observations of eruptive activity are recorded, surface exposure age-dating of lava flows suggests that activity occurred as recently as 290 AD approximately 300 years, according to scientists. Local Aymara stories also suggest that the volcano has erupted during the past 1,000 years. This detailed photograph highlights the symmetrical cone of Parinacota, with its well-developed summit crater (elevation 6,348 meters above sea level) at center. Dark brown to dark gray surfaces to the east and west of the summit include lava flows, pyroclastic deposits, and ash. A companion volcano, Pomerape, is located across a low saddle to the north ? scientists believe this volcano last erupted during the Pleistocene Epoch (extending from approximately 3 million to 12,000 years ago). The summits of both volcanoes are covered by white permanent snowpack and small glaciers. Together, the two volcanoes form the Nevados de Payachata volcanic area. Eruptive activity at Parinacota has directly influenced development of the local landscape beyond the emplacement of volcanic deposits ? approximately 8,000 years ago the western flank of the volcano collapsed, creating a debris avalanche that traveled 22 kilometers to the west. This debris avalanche blocked drainages, leading to the formation of Lake Chungara to the south (upper right). The uneven, hummocky surface of the debris avalanche deposit provides ample catchments for water, as evidenced by the numerous small ponds and Cotacotani Lake to the west.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2011/5110/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2011/5110/"><span>Thermal mapping of Hawaiian volcanoes with ASTER satellite data</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Patrick, Matthew R.; Witzke, Coral-Nadine</p> <p>2011-01-01</p> <p>Thermal mapping of volcanoes is important to determine baseline thermal behavior in order to judge future thermal activity that may precede an eruption. We used cloud-free kinetic temperature images from the ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) sensor obtained between 2000 and 2010 to produce thermal maps for all five subaerial volcanoes in Hawaii that have had eruptions in the Holocene (Kīlauea, Mauna Loa, Hualālai, Mauna Kea, and Haleakalā). We stacked the images to provide time-averaged thermal maps, as well as to analyze temperature trends through time. Thermal areas are conspicuous at the summits and rift zones of Kīlauea and Mauna Loa, and the summit calderas of these volcanoes contain obvious arcuate, concentric linear thermal areas that probably result from channeling of rising gas along buried, historical intracaldera scarps. The only significant change in thermal activity noted in the study period is the opening of the Halemaumau vent at Kīlauea's summit in 2008. Several small thermal anomalies are coincident with pit craters on Hualālai. We suspect that these simply result from the sheltered nature of the depression, but closer inspection is warranted to determine if genuine thermal activity exists in the craters. Thermal areas were not detected on Haleakalā or Mauna Kea. The main limitation of the study is the large pixel size (90 m) of the ASTER images, which reduces our ability to detect subtle changes or to identify small, low-temperature thermal activity. This study, therefore, is meant to characterize the broad, large-scale thermal features on these volcanoes. Future work should study these thermal areas with thermal cameras and thermocouples, which have a greater ability to detect small, low-temperature thermal features.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/6918805-granular-activated-carbon-pilot-treatment-studies-explosives-removal-from-contaminated-groundwater','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/6918805-granular-activated-carbon-pilot-treatment-studies-explosives-removal-from-contaminated-groundwater"><span>Granular activated carbon pilot treatment studies for explosives removal from contaminated groundwater</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Wujcik, W.J.; Lowe, W.L.; Marks, P.J.</p> <p>1992-08-01</p> <p>Manufacturing activities at Army Ammunition Plants (AAPs) result in the production of organic wastewaters that contain both explosive residues and other organic chemicals. As a result of past waste practices at such plants, explosive residues may leach through the soil and contaminate groundwater. Two pilot studies were performed to evaluate the use of granular activated carbon (GAC) to treat groundwater contaminated with explosives at Badger AAP and Milan AAP. An additional goal of the Badger AAP study was to examine the potential discharge of explosives 2,4-DNT and 2,6-DNT from a packed column air stripper used to remove volatile organic compoundsmore » from groundwater. A laboratory method was developed for the BAAP study to permit lower detection levels for 2,4-DNT and 2,6-DNT (0.46[mu]g/L and 0.017 [mu]g/L, respectively). The studies concluded that removal of explosives from groundwater using continuous flow GAC is feasible. 14 refs., 10 figs., 11 tabs.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/5561038-installation-restoration-program-environmental-technology-development-task-order-use-activated-carbon-treatment-explosives-contaminated-ground-water-badger-army-ammunition-plant-baap-final-report-jun-aug','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/5561038-installation-restoration-program-environmental-technology-development-task-order-use-activated-carbon-treatment-explosives-contaminated-ground-water-badger-army-ammunition-plant-baap-final-report-jun-aug"><span>Installation-Restoration Program environmental-technology development. Task order 3. Use of activated carbon for treatment of explosives-contaminated ground water at the Badger Army Ammunition Plant (BAAP). Final report Jun 88-Aug 89</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Wujcik, W.J.; Lowe, W.L.; Marks, P.J.</p> <p>1989-08-01</p> <p>The United States Army operates explosives manufacturing plants to produce various forms of explosives used in military ordnance. Manufacturing activities at such plants result in the production of organic wastewaters that contain both explosive residues and other organic chemicals. Several treatment technologies have been developed to treat these wastewaters for final discharge. Past waste handling practices at explosives manufacturing plants commonly included the use of the unlined lagoons or pits for containing process wastewaters. As a result of these past practices, some explosives residues may leach through the soil and contaminated groundwater. Therefore, the treatment of contaminated groundwater may bemore » required.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title27-vol1/pdf/CFR-2011-title27-vol1-sec9-67.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title27-vol1/pdf/CFR-2011-title27-vol1-sec9-67.pdf"><span>27 CFR 9.67 - Catoctin.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-04-01</p> <p>..., Maryland,” 7.5 minute series, 1953 (Photorevised 1979); (5) “Blue Ridge Summit Quadrangle, Maryland... Furnace Quadrangle,” “Blue Ridge Summit Quadrangle,” and “Emmitsburg Quadrangle” maps to the point of... the Maryland-Pennsylvania State line on the “Emmitsburg Quadrangle,” “Blue Ridge Summit Quadrangle...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title27-vol1/pdf/CFR-2010-title27-vol1-sec9-67.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title27-vol1/pdf/CFR-2010-title27-vol1-sec9-67.pdf"><span>27 CFR 9.67 - Catoctin.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-04-01</p> <p>..., Maryland,” 7.5 minute series, 1953 (Photorevised 1979); (5) “Blue Ridge Summit Quadrangle, Maryland... Furnace Quadrangle,” “Blue Ridge Summit Quadrangle,” and “Emmitsburg Quadrangle” maps to the point of... the Maryland-Pennsylvania State line on the “Emmitsburg Quadrangle,” “Blue Ridge Summit Quadrangle...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title27-vol1/pdf/CFR-2012-title27-vol1-sec9-67.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title27-vol1/pdf/CFR-2012-title27-vol1-sec9-67.pdf"><span>27 CFR 9.67 - Catoctin.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-04-01</p> <p>..., Maryland,” 7.5 minute series, 1953 (Photorevised 1979); (5) “Blue Ridge Summit Quadrangle, Maryland... Furnace Quadrangle,” “Blue Ridge Summit Quadrangle,” and “Emmitsburg Quadrangle” maps to the point of... the Maryland-Pennsylvania State line on the “Emmitsburg Quadrangle,” “Blue Ridge Summit Quadrangle...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title27-vol1/pdf/CFR-2014-title27-vol1-sec9-67.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title27-vol1/pdf/CFR-2014-title27-vol1-sec9-67.pdf"><span>27 CFR 9.67 - Catoctin.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-04-01</p> <p>..., Maryland,” 7.5 minute series, 1953 (Photorevised 1979); (5) “Blue Ridge Summit Quadrangle, Maryland... Furnace Quadrangle,” “Blue Ridge Summit Quadrangle,” and “Emmitsburg Quadrangle” maps to the point of... the Maryland-Pennsylvania State line on the “Emmitsburg Quadrangle,” “Blue Ridge Summit Quadrangle...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title27-vol1/pdf/CFR-2013-title27-vol1-sec9-67.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title27-vol1/pdf/CFR-2013-title27-vol1-sec9-67.pdf"><span>27 CFR 9.67 - Catoctin.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-04-01</p> <p>..., Maryland,” 7.5 minute series, 1953 (Photorevised 1979); (5) “Blue Ridge Summit Quadrangle, Maryland... Furnace Quadrangle,” “Blue Ridge Summit Quadrangle,” and “Emmitsburg Quadrangle” maps to the point of... the Maryland-Pennsylvania State line on the “Emmitsburg Quadrangle,” “Blue Ridge Summit Quadrangle...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED523544.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED523544.pdf"><span>11th Annual Legislative Summit, 2008</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>National Indian Education Association, 2008</p> <p>2008-01-01</p> <p>Several papers were presented during the 11th Annual National Indian Education Association (NIEA) Legislative Summit. This volume contains the following briefing papers presented during the summit: (1) Reauthorization of No Child Left Behind Strengthen Native American Education; (2) The Johnson O'Malley Program; (3) Legislation to Address…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2011-01-26/pdf/2011-1619.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2011-01-26/pdf/2011-1619.pdf"><span>76 FR 4725 - Apria Healthcare Customer Service Department; Fourteen Locations in Missouri Cameron, Cape...</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2011-01-26</p> <p>..., Fenton, Joplin, Lee's Summit, Pleasant Valley, Poplar Bluff, Rolla, Springfield, St. Joseph, St. Peters... in Missouri: Cameron, Cape Girardeau, Columbia, Farmington, Fenton, Joplin, Lee's Summit, Pleasant..., Farmington, Fenton, Joplin, Lee's Summit, Pleasant Valley, Poplar Bluff, Rolla, Springfield, St. Joseph, St...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009JVGR..184..473M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009JVGR..184..473M"><span>Correlations of volcanic ash texture with explosion earthquakes from vulcanian eruptions at Sakurajima volcano, Japan</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miwa, T.; Toramaru, A.; Iguchi, M.</p> <p>2009-07-01</p> <p>We compare the texture of volcanic ash with the maximum amplitude of explosion earthquakes ( Aeq) for vulcanian eruptions from Sakurajima volcano. We analyze the volcanic ash emitted by 17 vulcanian eruptions from 1974 to 1987. Using a stereoscopic microscope, we classify the glassy particles into smooth surface particles (S-type particles) and non-smooth surface particles (NS-type particles) according to their surface conditions—gloss or non-gloss appearance—as an indicator of the freshness of the particles. S-type particles are further classified into V-type particles (those including vesicles) and NV-type particles (those without vesicles) by means of examinations under a polarized microscopic of polished thin sections. Cross-correlated examinations against seismological data show that: 1) the number fraction of S-type particles (S-fraction) has a positive correlation with Aeq, 2) the number ratio of NV-type particles to V-type particles (the N/V number ratio) has a positive correlation with Aeq, and 3) for explosions accompanied with BL-type earthquake swarms, the N/V number ratio has a negative correlation with the duration of the BL-Swarms. BL-Swarms refer to the phenomenon of numerous BL-type earthquakes occurring within a few days, prior to an increase in explosive activity [Kamo, K., 1978. Some phenomena before the summit crater eruptions at Sakura-zima volcano. Bull. Volcanol. Soc. Japan., 23, 53-64]. The positive correlation between the N/V number ratio and Aeq could indicate that a large amount of separated gas from fresh magma results in a large Aeq. Plagioclase microlite textual analysis of NV-type particles from five explosive events without BL-Swarms shows that the plagioclase microlite number density (MND) and the L/ W (length/width) ratio have a positive correlation with Aeq. A comparison between textural data (MND, L/ W ratio, crystallinity) and the result of a decompression-induced crystallization experiment [Couch, S., Sparks, R.S.J., Carroll, M.R., 2003. The kinetics of degassing-induced crystallization at Soufriere Hills volcano, Montserrat. J. Petrol., 44, 1477-1502.] suggests that a plagioclase microlite texture of volcanic ash from eruptions without BL-Swarms could be generated by a decompression of 100-160 MPa. If the MND is controlled by the water exsolution rate from melt, the positive correlation between the MND and Aeq may suggest that Aeq becomes large when the effective decompression is large and the water exsolution rate is high (from 6.2 × 10 - 5 to 1.9 × 10 - 4 wt.%/s). The estimated magma ascent rate ranges from 0.11 to 0.35 m/s, which is one order of magnitude faster than that of an effusive eruption, and one to three orders slower than those for a (sub-) plinian eruption. This suggests that the ascent rate of magma plays an important role in the occurrence of vulcanian eruptions. We propose a simple model for vulcanian eruptions at Sakurajima volcano that takes into account the correlation between the S-fraction and Aeq.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28530444','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28530444"><span>Real-World Strategies to Engage and Retain Racial-Ethnic Minority Young Men Who Have Sex with Men in HIV Prevention Services.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Freese, Thomas E; Padwa, Howard; Oeser, Brandy T; Rutkowski, Beth A; Schulte, Marya T</p> <p>2017-06-01</p> <p>Racial/ethnic minority young men who have sex with men (YMSM)-particularly African Americans and Hispanics/Latinos-are at particularly high risk for HIV infection. Devising strategies to improve engagement and retention in HIV prevention services among minority YMSM is critical if the United States is going to achieve the National HIV/AIDS Strategy goal of reducing HIV health-related disparities. This article presents findings from a national summit on racial/ethnic YMSM services convened by the Substance Abuse and Mental Health Services Administration-funded Center of Excellence on Racial and Ethnic Minority Young Men Who Have Sex with Men and Other Lesbian, Gay, Bisexual, and Transgender Populations (YMSM + LGBT CoE) in September 2015. The summit included (1) subgroup discussions focused on issues related to treatment access, outreach/engagement/retention, continuing care/recovery support, and health literacy for minority YMSM; and (2) a ranking process, where the NIATx Nominal Group Technique was used to identify the strategies and approaches that summit participants believed to be most promising for engaging and retaining minority YMSM in HIV prevention services. Analyses of results from summit activities highlight four key cross-cutting strategies-utilizing peers, providing holistic care, making services fun, and utilizing technology-as critical for engaging minority YMSM in HIV prevention care. Examples of programs that utilize these strategies and implications of these findings for policy and practice are discussed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss026e025437.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss026e025437.html"><span>Earth Observations taken by Expedition 26 Crewmember</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2011-02-10</p> <p>ISS026-E-025437 (10 Feb. 2011) --- Pico de Orizaba, Mexico is featured in this image photographed by an Expedition 26 crew member on the International Space Station. The snow and ice-clad peak of Pico de Orizaba (also known as Citlaltepetl) boasts a summit elevation of 5,675 meters (18,619 feet) above sea level, making it the highest peak in Mexico and North America’s highest volcano. It is also one of three volcanic peaks in Mexico—together with Popocatepetl and Iztaccihuatl—that retain summit glaciers. Pico de Orizaba is part of the Trans-Mexican Volcanic Belt that extends roughly east-west across Mexico. The last recorded eruption took place in 1846; while the volcano is considered dormant at present, geologists continue to investigate the potential hazards associated with a renewal of activity. Shadows accentuate several features of the Pico de Orizaba stratovolcano visible in this photograph from the space station. The 300-meter-deep summit crater is clearly visible against surrounding ice and snow cover at center. Several lava flows extend down the flanks of the volcano, made readily visible by prominent cooling ridges along their sides known as flow levees—one of the most clearly visible examples is located on the southwest flank of the cone. The extinct Sierra Negra volcano to the southwest has a summit elevation of 4,640 meters (15,223 feet) above sea level; while not as lofty as Pico de Orizaba, it is also one of Mexico’s highest peaks.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA03493.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA03493.html"><span>Chiliques Volcano, Chile</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2002-04-19</p> <p>A January 6, 2002 ASTER nighttime thermal infrared image of Chiliques volcano in Chile shows a hot spot in the summit crater and several others along the upper flanks of the edifice, indicating new volcanic activity. Examination of an earlier nighttime thermal infrared image from May 24, 2000 showed no thermal anomaly. Chiliques volcano was previously thought to be dormant. Rising to an elevation of 5778 m, Chiliques is a simple stratovolcano with a 500-m-diameter circular summit crater. This mountain is one of the most important high altitude ceremonial centers of the Incas. It is rarely visited due to its difficult accessibility. Climbing to the summit along Inca trails, numerous ruins are encountered; at the summit there are a series of constructions used for rituals. There is a beautiful lagoon in the crater that is almost always frozen. The daytime image was acquired on November 19, 2000 and was created by displaying ASTER bands 1,2 and 3 in blue, green and red. The nighttime image was acquired January 6, 2002, and is a color-coded display of a single thermal infrared band. The hottest areas are white, and colder areas are darker shades of red. Both images cover an area of 7.5 x 7.5 km, and are centered at 23.6 degrees south latitude, 67.6 degrees west longitude. Both images cover an area of 7.5 x 7.5 km, and are centered at 23.6 degrees south latitude, 67.6 degrees west longitude. http://photojournal.jpl.nasa.gov/catalog/PIA03493</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA03799&hterms=mauna+loa+volcanic+history&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmauna%2Bloa%2Bvolcanic%2Bhistory','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA03799&hterms=mauna+loa+volcanic+history&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmauna%2Bloa%2Bvolcanic%2Bhistory"><span>Arsia Mons</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2002-01-01</p> <p>(Released 20 May 2002) The Science This THEMIS visible image shows a portion of the summit region of Arsia Mons, one of the four giant volcanoes in the Tharsis region of Mars. This volcano stands over 20 km above the surrounding plains, and is approximately 450 km in diameter at its base. A large volcanic crater known as a 'caldera' is located at the summit of all of the Tharsis volcanoes. These calderas are produced by massive volcanic explosions and collapse. The Arsia Mons summit caldera alone is over 120 km in diameter, making it larger than many volcanoes on Earth. The THEMIS image shows a portion of the eastern wall of the caldera, revealing the steep walls and linear features associated with the collapse that formed the caldera. The ridge with linear faults that extends from the lower left toward the center right was formed at some stage during a collapse event. Several circular pits are present, and several of these pits appear to have coalesced into a long, unusual trough. These pits and troughs likely formed when lava was removed from beneath them and the overlying surface collapsed. Numerous lava flows can be seen on the floor of the caldera. Many of these flows occurred after the collapse that formed the caldera crater, and have buried many of the pre-existing features. The faulted, pitted ridge appears to have been partially flooded by these lava flows, indicating that the caldera of Arsia Mons has undergone a complex history of numerous events. The wispy bright features throughout the image are water-ice clouds that commonly form over the volcano summits during the early northern spring when this image was acquired. The Story When the Martian volcano Arsia Mons exploded long ago, it sent lava spewing out everywhere. With the removal of this molten material, the volcano then collapsed at its opening (the top of its cone) to form a sunken volcanic crater known as a caldera. You can see it more fully in the context image to the right. The eastern wall of the caldera is the pale white strip running diagonally across the bottom third of the image. By looking at this steep wall and the streaks running down its sides, you can imagine how all of the remaining material rushed down into the void left by expelled magma and ash to form the caldera depression. Numerous lava flows that occurred after the collapse texturize the floor of the caldera, and have buried many of its pre-existing features. These later lava flows might be a little harder to see, because wispy bright features blur this image slightly, giving it an almost marbled, hazy appearance. They are water-ice clouds that typically form over the volcano summits during the early northern spring. What they don't obscure very much is the raised ridge created during the collapse of the volcano's cone (running slightly north of the caldera wall along the same diagonal). Draped across the smoother caldera floor, this pitted ridge has been partially flooded by lava flows, indicating quite a complex history of geologic events has taken place here. Faults cut through the ridge, contributing to its streamer-like appearance. And, in a process somewhat like the formation of the caldera itself, all of the round and oblong pits and troughs in the ridge formed when lava was removed from underneath these areas, and the overlying surface then collapsed. Arsia Mons is one of the four giant Martian volcanoes found in a region called Tharsis. Arsia Mons is about 270 miles wide in diameter at its base, and rises 12 miles high above the surrounding plains. The caldera at its summit is more than 72 miles wide, making it larger than volcanoes on Earth. By comparison, the largest volcano on Earth is Mauna Loa on the island of Hawaii, which is about 6.3 miles high and 75 miles wide in diameter at its base.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA....13586H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA....13586H"><span>Hydrothermal circulation at the world's highest lake? An environmental study of the Licancabur Volcano crater lake as a terrestrial analog to martian paleolakes.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hock, A. N.; Cabrol, N. A.; Grin, E. A.; Fike, D. A.; Paige, D. A.; 2002 Licancabur Expedition Team</p> <p>2003-04-01</p> <p>At approximately 6000 meters above sea level, the crater of Licancabur Volcano (22 50'S, 67 53'W) houses the highest lake in the world, yet remains largely unexplored. In particular, the physical environment of the lake--particularly its stability and any remaining geothermal activity--is not well understood. Using a model for the temperature of maximum density for freshwater as a function of pressure (Eklund), we calculated that the bottom water temperature of the summit lake should be approximately 4 C. However, Leach et al. measured the water temperature at depth to be 6 C. This discrepancy, as well as the observation that the lake remains liquid for much of the year despite sub freezing air temperatures, suggests that there may be a heat source supporting the lake's temperature and biological community. We present the results of two studies here: the goal of this work is to understand the role of geothermal fluid input to the summit lake in terms of energy balance, the physical constraints on endemic biology, and the analogy to ancient martian hydrothermal systems (e.g. volcanic lakes, crater lakes, hot springs, etc.). First, we present physical data from the lake in a new model of energy balance. In situ measurements of pH, temperature, and total dissolved solids suggest that the Licancabur summit lake is a ¨low-activity¨ (as per Pasternack and Varekamp) lake with a diffuse geothermal fluid input. Secondly, mass spectrometry and ion chromatography were used to study water samples taken from the summit lake, as well as two local lagunas and several geothermal springs at the base of the volcano. The case for a hydrothermal system in the summit lake is further strengthened here by preliminary ion chromatography results, which show elevated concentrations of sulfate and chloride with respect to local meteoric waters. Understanding the relationship between the physical environment and biotic community remains the mainstay for future work on this project in an effort to understand this environment--not only as a unique one among terrestrial lakes--but as one that may help us to understand the history of water and life on Mars.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=models+AND+Innovation+AND+interactive&pg=3&id=EJ1155080','ERIC'); return false;" href="https://eric.ed.gov/?q=models+AND+Innovation+AND+interactive&pg=3&id=EJ1155080"><span>Pacesetter in Personalized Learning</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Jacobs, Joanne</p> <p>2017-01-01</p> <p>The Chicago International Charter School (CICS) Irving Park's middle school is one of 130 schools nationwide piloting the Summit Learning Program (SLP), developed--and offered entirely free--by Summit Public Schools, a high-performing charter network based in California. Summit's eight schools, two of them in Washington State, are known for an…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=Missiles&pg=5&id=EJ328434','ERIC'); return false;" href="https://eric.ed.gov/?q=Missiles&pg=5&id=EJ328434"><span>Dialogue on Dialog: Interview with Roger Summit.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Newman, Donald</p> <p>1986-01-01</p> <p>Presents interview with Roger Summit, the president of Dialog Information Services, Inc. Highlights include Summit's role as chief architect of the system, the inception of Dialog and its beginnings at Lockheed Missiles and Space Company, services provided by Dialog, a challenge for libraries, and future developments and services. (EJS)</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=Cotton&id=EJ941425','ERIC'); return false;" href="https://eric.ed.gov/?q=Cotton&id=EJ941425"><span>Cotton and Sustainability: Impacting Student Learning through Sustainable Cotton Summit</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Ha-Brookshire, Jung; Norum, Pamela</p> <p>2011-01-01</p> <p>Purpose: The purpose of this paper is to examine the effect of intensive extra-curricular learning opportunities on students' knowledge, skills, and attitudes regarding cotton and sustainability. Design/methodology/approach: A three-phase extra-curricular learning opportunity was designed to include a Sustainable Cotton Summit; pre-summit and…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2012-02-08/pdf/2012-2825.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2012-02-08/pdf/2012-2825.pdf"><span>77 FR 6534 - Malheur National Forest; Oregon; Summit Logan Grazing Authorization Project</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2012-02-08</p> <p>... Creek and Summit Prairie allotments. These allotments are within the Upper Malheur River and Upper North Fork Malheur River watersheds. The Summit Logan Grazing Authorization Project area is located south and west of Prairie City, Oregon and encompasses approximately 40,272 acres of National Forest System Lands...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/EJ855049.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/EJ855049.pdf"><span>2007 Youth Policy Summit Summary</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Reid, Ellen; Fussell, Annemarie; Templin, Elizabeth</p> <p>2007-01-01</p> <p>The NCSSSMST (National Consortium for Specialized Secondary Schools of Mathematics, Science and Technology) and Keystone Science School co-sponsored two Youth Policy Summits during the summer of 2007. Forty students represented 10 high schools from across the country at each Summit, meeting for a week in June and August at Keystone Science School…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2013-03-27/pdf/2013-07031.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2013-03-27/pdf/2013-07031.pdf"><span>78 FR 18611 - Summit on Color in Medical Imaging; Cosponsored Public Workshop; Request for Comments</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2013-03-27</p> <p>...] Summit on Color in Medical Imaging; Cosponsored Public Workshop; Request for Comments AGENCY: Food and...: The Food and Drug Administration (FDA) and cosponsor International Color Consortium (ICC) are announcing the following public workshop entitled ``Summit on Color in Medical Imaging: An International...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2012-06-19/pdf/2012-14823.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2012-06-19/pdf/2012-14823.pdf"><span>77 FR 36549 - Nursing Workforce Diversity Invitational Summit-“Nursing in 3D: Workforce Diversity, Health...</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2012-06-19</p> <p>... DEPARTMENT OF HEALTH AND HUMAN SERVICES Health Resources and Services Administration Nursing Workforce Diversity Invitational Summit--``Nursing in 3D: Workforce Diversity, Health Disparities, and..., Division of Nursing, will host an invitational summit that focuses on Nursing Workforce Diversity (NWD...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=Library+AND+virtual&id=EJ930804','ERIC'); return false;" href="https://eric.ed.gov/?q=Library+AND+virtual&id=EJ930804"><span>Ebook Summit: Our Ebook Challenge</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Library Journal, 2010</p> <p>2010-01-01</p> <p>Over 2000 participants made the daylong programming at the "Library Journal"/"School Library Journal" Virtual Ebook Summit, September 29, a robust conversation and not just within the summit interface but also in tweets with the #ebooksummit hashtag (and beyond) and in libraries across the country where participants logged in to take part. The…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28076263','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28076263"><span>"A Paradox Persists When the Paradigm Is Wrong": Pisacano Scholars' Reflections from the Inaugural Starfield Summit.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Doohan, Noemi; Coutinho, Anastasia J; Lochner, Jennifer; Wohler, Diana; DeVoe, Jennifer</p> <p></p> <p>The inaugural Starfield Summit was hosted in April 2016 by the Robert Graham Center for Policy Studies in Family Medicine and Primary Care with additional partners and sponsors, including the Pisacano Leadership Foundation (PLF). The Summit addressed critical topics in primary care and health care delivery, including payment, measurement, and team-based care. Invited participants included an interdisciplinary group of pediatricians, family physicians, internists, behaviorists, trainees, researchers, and advocates. Among the family physicians invited were both current and past PLF (Pisacano) scholars. After the Summit, a small group of current and past Pisacano scholars formed a writing group to reflect on and summarize key lessons and conclusions from the Summit. A Summit participant's statement, "a paradox persists when the paradigm is wrong," became a repeated theme regarding the paradox of primary care within the context of the health care system in the United States. The Summit energized participants to renew their commitment to Dr. Starfield's 4 C's of Primary Care (first contact access, continuity, comprehensiveness, and care coordination) and to the Quadruple Aim (quality, value, and patient and physician satisfaction) and to continue to explore how primary care can best shape the future of the nation's health care system. © Copyright 2016 by the American Board of Family Medicine.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JVGR..332..109N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JVGR..332..109N"><span>Holocene tephra succession of Puyehue-Cordón Caulle and Antillanca/Casablanca volcanic complexes, southern Andes (40-41°S)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Naranjo, J. A.; Singer, B. S.; Jicha, B. R.; Moreno, H.; Lara, L. E.</p> <p>2017-02-01</p> <p>Puyehue-Cordón Caulle and Antillanca volcanic complexes are two of at least 50 active frontal arc volcanoes that define the 1400 km-long Southern Volcanic Zone of Chile. Holocene tephra deposits in Chile and Argentina (40-41°S) up to 100 km east of these volcanoes comprise at least five voluminous ( 1 to 8 km3) pyroclastic-fall layers that preceded several recently deposited Cordón Caulle pumice fallouts. Field observations of proximal, medium, and distal facies of the deposits, in conjunction with geochronology and geochemistry of the volcanic complexes, indicate that three fall layers are derived from Puyehue volcano (Puyehue 1 and 2, and Mil Hojas), whereas two are sourced from the Antillanca complex (Playas Blanca-Negra, and Nahuel Huapi Tephra), 20 km to the south. The oldest tephra (calibrated 14C age 10.49 ± 0.12 ka, 2σ), found only at medium-distal facies, is deposited directly on granitic moraine boulders and consists of deeply weathered, orange dacitic pumice lapilli. The next prominent tephra at 7 ka comprises dacitic pumice and its age is equivalent to a rhyodacitic dome exposed in the Puyehue summit crater. Above these deposits there are phases of a complex eruption consisting of a conspicuous compositionally-zoned tephra. It also comprises a pyroclastic density current, together with lithic rich and scoriaceous fallout deposits. Mineralogical, geochemical, and Sr isotope evidence, plus the isopach maps, confirm that this sequence of eruptive events is sourced from Antillanca at 1932 ± 68 yrBP. The total volume of this eruptive sequence exceeds 8 km3, making it the largest Holocene eruption from either volcanic complex. This eruption was likely responsible for the destruction of an ancestral Antillanca volcano and the formation of a 4.5 km diameter caldera. A distinctive younger unit in the region is a voluminous rhyodacitic pumice fall (calibrated 14C age 1.11 ± 0.07 ka), above which a series of several alternating dark lithic and pumice lapilli beds accumulated. Correlation with proximal deposits indicates that the 1.11 ka eruption was derived from Puyehue and destroyed 3 km3 of rhyodacitic domes at this volcano summit. Historic explosive activity at the nascent Casablanca volcano and along Cordón Caulle, including the 2011-2012 eruption ( 1 km3 of uncompacted pumice), the largest from this fissural zone, emphasizes an increased risk for volcanic hazards in central Chile and Argentina.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA22154.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA22154.html"><span>Investigating Mars: Arsia Mons</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2017-12-29</p> <p>This image shows part of the southeastern flank of Arsia Mons, including the flat lying flows around the base of the volcano. These flows are located at the bottom of the image. Numerous small lava channels are visible aligned sub-parallel to the base of the volcano. Several narrow, lobate flows show the downslope direction from the top left of the image towards the bottom right. Running against this elevation change are large paired faults called graben. Graben form by faults that have allowed the material between them to "slide" down. The resultant topography is a linear depression. None of the lobate flows enter and then run along the fault valley, indicating that the faulting occurred after the lava flows. Arsia Mons is the southernmost of the Tharsis volcanoes. It is 270 miles (450km) in diameter, almost 12 miles (20km) high, and the summit caldera is 72 miles (120km) wide. For comparison, the largest volcano on Earth is Mauna Loa. From its base on the sea floor, Mauna Loa measures only 6.3 miles high and 75 miles in diameter. A large volcanic crater known as a caldera is located at the summit of all of the Tharsis volcanoes. These calderas are produced by massive volcanic explosions and collapse. The Arsia Mons summit caldera is larger than many volcanoes on Earth. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 17691 Latitude: -11.2622 Longitude: 241 Instrument: VIS Captured: 2005-12-09 23:06 https://photojournal.jpl.nasa.gov/catalog/PIA22154</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMED51B0598H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMED51B0598H"><span>Climate Change Student Summits: A Model that Works (Invited)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Huffman, L. T.</p> <p>2013-12-01</p> <p>The C2S2: Climate Change Student Summit project has completed four years of activities plus a year-long longitudinal evaluation with demonstrated positive impacts beyond the life of the project on both students and teachers. This presentation will share the lessons learned about implementing this climate change science education program and suggest that it is a successful model that can be used to scale up from its Midwestern roots to achieve measurable national impact. A NOAA Environmental Literacy grant allowed ANDRILL (ANtarctic geological DRILLing) to grow a 2008 pilot program involving 2 Midwestern sites, to a program 4 years later involving 10 sites. The excellent geographical coverage included 9 of the U.S. National Climate Assessment regions defined by the U.S. Global Change Research Program. Through the delivery of two professional development (PD) workshops, a unique opportunity was provided for both formal and informal educators to engage their classrooms/audiences in understanding the complexities of climate change. For maximum contact hours, the PD experience was extended throughout the school year through the use of an online grouphub. Student teams were involved in a creative investigative science research and presentation experience culminating in a Climate Change Student Summit, an on-site capstone event including a videoconference connecting all sites. The success of this program was based on combining multiple aspects, such as encouraging the active involvement of scientists and early career researchers both in the professional development workshops and in the Student Summit. Another key factor was the close working relationships between informal and formal science entities, including involvement of informal science learning facilities and informal science education leaders. The program also created cutting-edge curriculum materials titled the ELF, (Environmental Literacy Framework with a focus on climate change), providing an earth systems approach to climate change education which have been successfully integrated into existing curricula in grades 4-12, as well as at numerous science museums.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.V23E0520M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.V23E0520M"><span>An Oscillation of the Crack-like Conduit at Nevado del Ruiz Volcano, Colombia, Inferred from Multi-band Analyses of Very Long Period Seismic Events</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maeda, Y.; Kumagai, H.; Londono, J. M.; Lopez, C. M.; Castaño, L. M.; Beatriz, B.; García, L.</p> <p>2017-12-01</p> <p>Nevado del Ruiz is an active volcano in Colombia, which continues eruption activity and has been monitored by 13 broadband and 3 short-period seismic stations. In 2015-2016, a joint Japan-Colombia team installed an automatic event detection and location system based on the amplitude source location (ASL) method. Kumagai et al. (IAVCEI, 2017) indicated the existence of a magma conduit extending from the NW flank to the summit based on ASL analyses of various seismic signals including long-period (LP) and very long period (VLP) events and tremors in a 5-10 Hz frequency band. In this study, we analyzed the VLP events by waveform inversion using eight summit stations in a frequency band of 0.3-0.7 Hz. We selected 14 VLP events from May to December 2016 based on signal-to-noise ratios and simplicity of the waveforms. We assumed a homogeneous P-wave velocity of 3.5 km/s with topography in the calculation of the Green functions. We conducted frequency-domain waveform inversion assuming a tensile crack source and investigated the best location and orientation of the crack by a grid search. The inversion results pointed to a low-angle ( 30°) NW-dipping crack near the top of the conduit (approximately 1 km below the summit). The estimated source time functions displayed two or three cycles of oscillations with the seismic moment of order of 1010-1011 N m. For these 14 events, the ASLs from the 5-10 Hz frequency band were also near the top of the conduit. These results suggest the VLP and high-frequency signals are generated by an oscillation of the crack-like conduit near the summit, which may be triggered by a volume change of magma ascending in the conduit.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.S51D2708R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.S51D2708R"><span>Frequency and Size of Strombolian Eruptions from the Phonolitic Lava Lake at Erebus Volcano, Antarctica: Insights from Infrasound and Seismic Observations on Bubble Formation and Ascent</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rotman, H. M. M.; Kyle, P. R.; Fee, D.; Curtis, A.</p> <p>2015-12-01</p> <p>Erebus, an active intraplate volcano on Ross Island, commonly produces bubble burst Strombolian explosions from a long-lived, convecting phonolitic lava lake. Persistent lava lakes are rare, and provide direct insights into their underlying magmatic system. Erebus phonolite is H2O-poor and contains ~30% anorthoclase megacrysts. At shallow depths lab measurements suggest the magma has viscosities of ~107 Pa s. This has implications for magma and bubble ascent rates through the conduit and into the lava lake. The bulk composition and matrix glass of Erebus ejecta has remained uniform for many thousands of years, but eruptive activity varies on decadal and shorter time scales. Over the last 15 years, increased activity took place in 2005-2007, and more recently in the 2013 austral summer. In the 2014 austral summer, new infrasound sensors were installed ~700 m from the summit crater hosting the lava lake. These sensors, supplemented by the Erebus network seismic stations, recorded >1000 eruptions between 1 January and 7 April 2015, with an average infrasound daily uptime of 9.6 hours. Over the same time period, the CTBT infrasound station IS55, ~25 km from Erebus, detected ~115 of the >1000 locally observed eruptions with amplitude decreases of >100x. An additional ~200 eruptions were recorded during local infrasound downtime. This represents an unusually high level of activity from the Erebus lava lake, and while instrument noise influences the minimum observable amplitude each day, the eruption infrasound amplitudes may vary by ~3 orders of magnitude over the scale of minutes to hours. We use this heightened period of variable activity and associated seismic and acoustic waveforms to examine mechanisms for bubble formation and ascent, such as rise speed dependence and collapsing foam; repose times for the larger eruptions; and possible eruption connections to lava lake cyclicity.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A23E3305S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A23E3305S"><span>Atmospheric Science Research at the Whiteface Mountain Adirondack High Peaks Observatory</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schwab, J. J.; Brandt, R. E.; Casson, P.; Demerjian, K. L.; Crandall, B. A.</p> <p>2014-12-01</p> <p>The Atmospheric Sciences Research Center established an atmospheric observatory at Whiteface Mountain in the Adirondacks in 1961. The current mountain top observatory building was built by the University at Albany in 1969-70 and the New York State Department of Environmental Conservation (DEC) began ozone measurements at this summit location in 1973. Those measurements continue to this day and constitute a valuable long term data record for tropospheric ozone in the northeastern U.S. The elevation of the summit is 1483 m above sea level, and is roughly 90 m above the tree line in this location. With a mean cloud base height of less than 1100 m at the summit, it is a prime location for cloud research. The research station headquarters, laboratories, offices, and a second measurement site are located at the Marble Mountain Lodge, perched on a shoulder northeast of the massif at an elevation of 604 m above sea level. Parameters measured at the site include meteorological variables, trace gases, precipitation chemistry, aerosol mass and components, and more. Precipitation and cloud chemistry has a long history at the lodge and summit locations, respectively, and continues to this day. Some data from the 40-year record will be shown in the presentation. In the late 1980's the summit site was outfitted with instrumentation to measure oxides of nitrogen and other ozone precursors. Measurements of many of these same parameters were added at the lodge site and continue to this day. In this poster we will give an overview of the Whiteface Mountain Observatory and its two measurement locations. We will highlight the parameters currently being measured at our sites, and indicate those measured by ASRC, as well as those measured by other organizations. We will also recap some of the historical activities and measurement programs that have taken place at the site, as alluded to above. Also included will be examples of the rich archive of trends data for gas phase species, precipitation chemistry, and particulate matter.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.3862P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.3862P"><span>Electrical resistivity tomography applied to a complex lava dome: 2D and 3D models comparison</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Portal, Angélie; Fargier, Yannick; Lénat, Jean-François; Labazuy, Philippe</p> <p>2015-04-01</p> <p>The study of volcanic domes growth (e.g. St. Helens, Unzen, Montserrat) shows that it is often characterized by a succession of extrusion phases, dome explosions and collapse events. Lava dome eruptive activity may last from days to decades. Therefore, their internal structure, at the end of the eruption, is complex and includes massive extrusions and lava lobes, talus and pyroclastic deposits as well as hydrothermal alteration. The electrical resistivity tomography (ERT) method, initially developed for environmental and engineering exploration, is now commonly used for volcano structure imaging. Because a large range of resistivity values is often observed in volcanic environments, the method is well suited to study the internal structure of volcanic edifices. We performed an ERT survey on an 11ka years old trachytic lava dome, the Puy de Dôme volcano (French Massif Central). The analysis of a recent high resolution DEM (LiDAR 0.5 m), as well as other geophysical data, strongly suggest that the Puy de Dôme is a composite dome. 11 ERT profiles have been carried out, both at the scale of the entire dome (base diameter of ~2 km and height of 400 m) on the one hand, and at a smaller scale on the summit part on the other hand. Each profile is composed of 64 electrodes. Three different electrode spacing have been used depending on the study area (35 m for the entire dome, 10 m and 5 m for its summit part). Some profiles were performed with half-length roll-along acquisitions, in order to keep a good trade-off between depth of investigation and resolution. Both Wenner-alpha and Wenner-Schlumberger protocols were used. 2-D models of the electrical resistivity distribution were computed using RES2DINV software. In order to constrain inversion models interpretation, the depth of investigation (DOI) method was applied to those results. It aims to compute a sensitivity index on inversion results, illustrating how the data influence the model and constraining models interpretation. Geometry and location of ERT profiles on the Puy de Dôme volcano allow to compute 3D inversion models of the electrical resistivity distribution with a new inversion code. This code uses tetrahedrons to discretize the 3D model and uses also a conventional Gauss-Newton inversion scheme combined to an Occam regularisation to process the data. It allows to take into account all the data information and prevents the construction of 3D artefacts present in conventional 2D inversion results. Inversion results show a strong electrical resistivity heterogeneity of the entire dome. Underlying volcanic edifices are clearly identified below the lava dome. Generally speaking, the flanks of the volcano show high resistivity values, and the summit part is more conductive but also very heterogeneous.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title27-vol1/pdf/CFR-2014-title27-vol1-sec9-124.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title27-vol1/pdf/CFR-2014-title27-vol1-sec9-124.pdf"><span>27 CFR 9.124 - Wild Horse Valley.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-04-01</p> <p>... direction approximately .9 mile to the summit of an unnamed hill having a marked elevation of 1,804 feet; (3... 1,824 feet; (4) Then south-southeasterly approximately .6 mile to the summit of an unnamed hill having a marked elevation of 1,866 feet; (5) Then south-southeasterly approximately .5 mile to the summit...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title27-vol1/pdf/CFR-2013-title27-vol1-sec9-124.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title27-vol1/pdf/CFR-2013-title27-vol1-sec9-124.pdf"><span>27 CFR 9.124 - Wild Horse Valley.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-04-01</p> <p>... direction approximately .9 mile to the summit of an unnamed hill having a marked elevation of 1,804 feet; (3... 1,824 feet; (4) Then south-southeasterly approximately .6 mile to the summit of an unnamed hill having a marked elevation of 1,866 feet; (5) Then south-southeasterly approximately .5 mile to the summit...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title27-vol1/pdf/CFR-2012-title27-vol1-sec9-124.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title27-vol1/pdf/CFR-2012-title27-vol1-sec9-124.pdf"><span>27 CFR 9.124 - Wild Horse Valley.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-04-01</p> <p>... direction approximately .9 mile to the summit of an unnamed hill having a marked elevation of 1,804 feet; (3... 1,824 feet; (4) Then south-southeasterly approximately .6 mile to the summit of an unnamed hill having a marked elevation of 1,866 feet; (5) Then south-southeasterly approximately .5 mile to the summit...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=mushrooms&id=EJ917664','ERIC'); return false;" href="https://eric.ed.gov/?q=mushrooms&id=EJ917664"><span>Wild Food Summit: Anishinaabe Relearning Traditional Gathering Practices</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Sorensen, Barbara Ellen</p> <p>2011-01-01</p> <p>Wild Food Summits is a program initiated by Steve Dahlberg, the White Earth Tribal & Community College Extension director. Dahlberg began Wild Food Summits to teach people about identifying and gathering wild greens, mushrooms, and other edible plant life. The whole community comes together to cook and eat the foods. The tribal college has…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.achp.gov/pubs-heritagetourismsummit2.html','SCIGOVWS'); return false;" href="http://www.achp.gov/pubs-heritagetourismsummit2.html"><span>ACHP | Heritage Tourism and the Federal Government: Summit II Proceedings</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.science.gov/aboutsearch.html">Science.gov Websites</a></p> <p></p> <p></p> <p>Search skip specific nav links Home arrow Publications arrow Intro: Heritage <em>Tourism</em> and the Federal Government: Summit IIÂReport of Proceedings Heritage <em>Tourism</em> and the Federal Government: Summit IIÂReport Heritage <em>tourism</em> promotes the preservation of communities' historic resources, educates tourists and local</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1259664','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1259664"><span>Announcing Supercomputer Summit</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Wells, Jack; Bland, Buddy; Nichols, Jeff</p> <p></p> <p>Summit is the next leap in leadership-class computing systems for open science. With Summit we will be able to address, with greater complexity and higher fidelity, questions concerning who we are, our place on earth, and in our universe. Summit will deliver more than five times the computational performance of Titan’s 18,688 nodes, using only approximately 3,400 nodes when it arrives in 2017. Like Titan, Summit will have a hybrid architecture, and each node will contain multiple IBM POWER9 CPUs and NVIDIA Volta GPUs all connected together with NVIDIA’s high-speed NVLink. Each node will have over half a terabyte ofmore » coherent memory (high bandwidth memory + DDR4) addressable by all CPUs and GPUs plus 800GB of non-volatile RAM that can be used as a burst buffer or as extended memory. To provide a high rate of I/O throughput, the nodes will be connected in a non-blocking fat-tree using a dual-rail Mellanox EDR InfiniBand interconnect. Upon completion, Summit will allow researchers in all fields of science unprecedented access to solving some of the world’s most pressing challenges.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.V41A2491W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.V41A2491W"><span>Campaign gravity results From kilauea volcano, hawaii, 2009-2011</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wilkinson, S. K.; Poland, M. P.; Battaglia, M.</p> <p>2011-12-01</p> <p>The gravity and leveling networks at Kilauea's summit caldera consist of approximately 60 benchmarks that are measured with a gravimeter as well as leveled for elevation data. Gravity data were collected in December 2009, June 2010 and March 2011. Elevation data were collected in 2009 and 2010. For the gravity survey completed in March 2011, we use InSAR and GPS data to assess elevation changes at the time of the gravity survey. During December 2009-March 2011, Kilauea's summit was characterized by minor deflation, following trends established in mid-2007. In mid-2010, however, the summit began to inflate, with a rate that increased significantly in October 2010. This inflation was associated with a decrease in the effusion rate from the volcano's east rift zone eruptive vents, suggesting that Kilauea's magma plumbing system was backing up. On March 5, 2011, a 2-km-long fissure eruption began about 3 km west of Pu`u `O`o, causing rapid summit deflation as magma drained from beneath the summit to feed the new eruptive vents. The fissure eruption ended on March 9, at which time the summit began to reinflate. Preliminary analysis of gravity data collected before and after the fissure eruption indicates a complex pattern of mass flow beneath the summit caldera. Net summit deformation was negligible between December 2009 and June 2010, but there is a residual gravity high centered near Halema'uma'u Crater. For the December 2009 to March 2011 time period, the caldera shows net subsidence. A positive residual gravity anomaly is located southeast of Halema'uma'u Crater while a negative residual gravity anomaly exists north of Halema'uma'u Crater. These patterns are somewhat unexpected, given the sudden draining of magma from beneath the summit during the March 5-9 fissure eruption. We conclude that the campaign gravity data were not collected at the optimal times to "catch" this event. Nevertheless, the data can still be used to assess different aspects of Kilauea's magma system.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2010-02-03/pdf/2010-2286.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2010-02-03/pdf/2010-2286.pdf"><span>75 FR 5575 - Taking and Importing Marine Mammals; Navy Training Activities Conducted in the Gulf of Alaska</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2010-02-03</p> <p>... present in the area to sound from various active tactical sonar sources or to pressure from underwater... utilizing mid- and high frequency active sonar sources and explosive detonations. These sonar and explosive...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8357E..0WF','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8357E..0WF"><span>Feasibility of culvert IED detection using thermal neutron activation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Faust, Anthony A.; McFee, John E.; Clifford, Edward T. H.; Andrews, Hugh Robert; Mosquera, Cristian; Roberts, William C.</p> <p>2012-06-01</p> <p>Bulk explosives hidden in culverts pose a serious threat to the Canadian and allied armies. Culverts provide an opportunity to conceal insurgent activity, avoid the need for detectable surface disturbances, and limit the applicability of conventional sub-surface sensing techniques. Further, in spite of the large masses of explosives that can be employed, the large sensor{target separation makes detection of the bulk explosive content challeng- ing. Defence R&D Canada { Sueld and Bubble Technology Industries have been developing thermal neutron activation (TNA) sensors for detection of buried bulk explosives for over 15 years. The next generation TNA sensor, known as TNA2, incorporates a number of improvements that allow for increased sensor-to-target dis- tances, making it potentially feasible to detect large improvised explosive devices (IEDs) in culverts using TNA. Experiments to determine the ability of TNA2 to detect improvised explosive devices in culverts are described, and the resulting signal levels observed for relevant quantities of explosives are presented. Observations conrm that bulk explosives detection using TNA against a culvert-IED is possible, with large charges posing a detection challenge at least as dicult as that of a deeply buried anti-tank landmine. Because of the prototype nature of the TNA sensor used, it is not yet possible to make denitive statements about the absolute sensitivity or detection time. Further investigation is warranted.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008EOSTr..89..406B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008EOSTr..89..406B"><span>Antarctic Treaty Summit to Focus on Global Science Policy Lessons</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Berkman, Paul Arthur; Walton, David W. H.; Weiler, C. Susan</p> <p>2008-10-01</p> <p>The Antarctic Treaty Summit, which will coincide with the fiftieth anniversary of the treaty's signing, will be held at the Smithsonian Institution's National Museum of Natural History, in Washington, D. C., from 30 November to 3 December 2009. The summit will provide an open international forum for scientists, legislators, lawyers, administrators, educators, students, corporate executives, historians, and other members of global civil society to explore science policy achievements from the first 50 years of the Antarctic Treaty. In addition, the summit will complement official government celebrations of the Antarctic Treaty anniversary that do not include public participation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110007316','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110007316"><span>Winter Camp: A Blog from the Greenland Summit, Part II</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Koenig, Lora</p> <p>2009-01-01</p> <p>An earlier issue presents the first half of the author's experience living and working at the National Science Foundation's (NSF) Greenland Summit Camp. The author is a remote-sensing glaciologist at NASA s Goddard Space Flight Center. She took measurements that will be used to validate data collected by NASA s Aqua, Terra, and Ice, Clouds, and land Elevation Satellite (ICESat) satellites with ground-truth measurements of the Greenland Ice Sheet she made at Summit Camp from November 2008-February 2009. This article presents excerpts from the second half of her stay and work at the Greenland Summit.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFMED51A..08E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFMED51A..08E"><span>International Volcanological Field School in Kamchatka and Alaska: Experiencing Language, Culture, Environment, and Active Volcanoes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eichelberger, J. C.; Gordeev, E.; Ivanov, B.; Izbekov, P.; Kasahara, M.; Melnikov, D.; Selyangin, O.; Vesna, Y.</p> <p>2003-12-01</p> <p>The Kamchatka State University of Education, University of Alaska Fairbanks, and Hokkaido University are developing an international field school focused on explosive volcanism of the North Pacific. An experimental first session was held on Mutnovsky and Gorely Volcanoes in Kamchatka during August 2003. Objectives of the school are to:(1) Acquaint students with the chemical and physical processes of explosive volcanism, through first-hand experience with some of the most spectacular volcanic features on Earth; (2) Expose students to different concepts and approaches to volcanology; (3) Expand students' ability to function in a harsh environment and to bridge barriers in language and culture; (4) Build long-lasting collaborations in research among students and in teaching and research among faculty in the North Pacific region. Both undergraduate and graduate students from Russia, the United States, and Japan participated. The school was based at a mountain hut situated between Gorely and Mutnovsky Volcanoes and accessible by all-terrain truck. Day trips were conducted to summit craters of both volcanoes, flank lava flows, fumarole fields, ignimbrite exposures, and a geothermal area and power plant. During the evenings and on days of bad weather, the school faculty conducted lectures on various topics of volcanology in either Russian or English, with translation. Although subjects were taught at the undergraduate level, lectures led to further discussion with more advanced students. Graduate students participated by describing their research activities to the undergraduates. A final session at a geophysical field station permitted demonstration of instrumentation and presentations requiring sophisticated graphics in more comfortable surroundings. Plans are underway to make this school an annual offering for academic credit in the Valley of Ten Thousand Smokes, Alaska and in Kamchatka. The course will be targeted at undergraduates with a strong interest in and aptitude for the physical sciences, not necessarily volcanology. It will also serve as an entry point for students wishing to make extended exchange visits to the Russian Far East or Alaska, and to graduate students in volcanology wishing to undertake thesis research in North Pacific volcanism. The school represents the first educational effort of the newly established Japan Kamchatka Alaska Subduction Project (JKASP), which seeks to bring scientists of our three nations together in the study of one shared geophysical province, the Kuril-Kamchatka-Aleutian Arcs.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.7270C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.7270C"><span>Integration of seismic and Ground-Based InSAR displacement data: a tool to understand conduit dynamic at Stromboli Volcano</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cauchie, Léna; Di Traglia, Federico; Casagli, Nicola; Saccorotti, Gilberto</p> <p>2014-05-01</p> <p>Stromboli is an open-conduit volcano, which does not experience pressurization of the magma storage and/or plumbing system able to produce ground deformations at the scale of the volcanic edifice. For any such system, localized inflations/deflations are rather expected in response to conduit processes, such as magma convection and uprising. Indeed, detectable ground deformations at Stromboli volcano have only been observed in association with dyke intrusion at shallow depth, prior to the opening of new eruptive fractures. In this work, we present the integration of seismic and Ground-Based Interferometric Synthetic Aperture Radar (GBInSAR) system displacement data recorded at Stromboli volcano aimed at a better understanding of the geophysical signals associated with magma dynamics in an open volcanic system. A cross-analysis between the tiny GBInSAR deformations and ground displacements in the seismological frequency band (0.02-10 Hz) is performed for the period spanning 6 June 2011 - 27 August 2011, which was characterized by an activity of higher intensity than usually observed. The period under study includes seven major explosions and two lava overflows from the NE vents (1-2 August and 18 August 2011). The time series of GBInSAR displacement at the summit vents area is positively correlated with both volcanic tremor amplitude and the number and amplitude of very-long-period (VLP) signals that are associated with the Strombolian explosions. While the correlation between GBInSAR and tremor time series takes its maximum at zero lag time, the variation in frequency and energy of VLP events anticipate by a few days the inflation of the vents area and the increase of volcanic tremor. We thus suggest a general mechanism to explain the observed trend in the geophysical signals. In our model, the arrival of fresh, gas-rich magma from below enhance slug formations, promoting convection and gas transfer throughout the conduit system. At the shallowest portion of the conduit, increase of volatile content causes density decrease/expansion of the magmatic column and augmented degassing activity, which respectively induce inflation of the conduit and increased tremor amplitudes. The temporal delay between increase of VLP and tremor amplitudes/conduit inflation can be interpreted in terms of the different time scales characterizing bulk gas transfer versus slug formation and ascent.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFM.V42A1007H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFM.V42A1007H"><span>Mixing of Magmatic Volatiles With Meteoric Groundwater in the Summit of Kilauea Volcano, Hawaii</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hurwitz, S.; Goff, F.; Janik, C. J.; Evans, W. C.; Counce, D. A.; Sorey, M. L.; Ingebritsen, S. E.</p> <p>2001-12-01</p> <p>Water samples were collected from the only deep well (Keller Well-NSF Well) on the summit of Kilauea volcano, Hawaii. The well was drilled in 1973 to a depth of 1262 m, but sat idle until 1998 when a drilling rig was used to remove mud and renew access to the hydrothermal system at a location very close to summit fumarolic activity. The chemistry and isotopic composition of fluid samples collected in 1998-2001 differ significantly from those of samples collected before 1998 and reported in previous studies. The water from the well is rich in sulfate and has a near-neutral pH. The major element chemistry differs significantly from seawater composition and from that of hydrothermal fluids from Kilauea's east rift zone. The well water has a low chloride concentration relative to typical magmatic-hydrothermal fluids and a high sulfate to bicarbonate ratio (approximately 4:1). Based on the S/Cl mass ratio and on carbon and helium isotopes in the well fluids, summit fumaroles and the parental Kilauea magma, we conclude that the hydrothermal fluids sampled from the well formed by condensation of magmatic volatiles into shallow, mainly meteoric groundwater. The oxygen and deuterium isotopic composition indicate that the meteoric component was recharged on the eastern margin of the caldera. Steam condensation and gas dissolution beneath the crater formed an acidic fluid that dissolved the host basalt at high temperatures. The hydrothermal fluid was then modified by cooling and precipitation of secondary minerals along a flow path away from the crater towards the well. Geochemical modeling based on fluid chemistry and geothermometry suggests that the well fluids equilibrated with an assemblage of secondary minerals at temperatures between 90 and 140oC. The C/S ratios in the well water, the parental magma, and the gas plume emanating from the caldera indicate that most of the sulfur degassed from the magma is scrubbed by groundwaters beneath the summit. However, based on the mean sulfate concentration in the well water and on the estimated mean annual water recharge in the caldera region, we conclude that the sulfate concentration in groundwater beneath Kilauea's summit must be an order of magnitude higher than that found in the well water.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED515556.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED515556.pdf"><span>A Clean Energy Roadmap: Forging the Path Ahead</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Ewing Marion Kauffman Foundation, 2010</p> <p>2010-01-01</p> <p>In 2010, the Ewing Marion Kauffman Foundation co-convened three cross-sector summits to develop recommendations for growing energy innovation in the United States. The first summit was held in Washington, D.C., on May 7, 2010, in partnership with the White House. Gallup and the city of Omaha, Nebraska, hosted the second summit on June 16, 2010,…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=goal+AND+framing&pg=4&id=EJ870368','ERIC'); return false;" href="https://eric.ed.gov/?q=goal+AND+framing&pg=4&id=EJ870368"><span>Howard's End: A Narrative Memoir of Political Contrivance, Neoconservative Ideology and the Australian History Curriculum</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Taylor, Tony</p> <p>2009-01-01</p> <p>In August 2006, Australia's conservative prime minister John Howard convened a history summit in Canberra. The purported goal of the summit was the framing of a nationally-acceptable curriculum in Australian history. However, as this article suggests, Howard's hidden intention was to use the summit as a device for introducing a narrowly…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title27-vol1/pdf/CFR-2014-title27-vol1-sec9-49.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title27-vol1/pdf/CFR-2014-title27-vol1-sec9-49.pdf"><span>27 CFR 9.49 - Central Delaware Valley.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-04-01</p> <p>... starting point of the following boundary description is the summit of Strawberry Hill, which is located in.... (2) Boundary Description: (i) From the summit of Strawberry Hill (475 feet) in a straight line to the... summit of Strawberry Hill (475 feet). [T.D. ATF-168, 49 FR 10117, Mar. 19, 1984, as amended by T.D. ATF...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title27-vol1/pdf/CFR-2013-title27-vol1-sec9-49.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title27-vol1/pdf/CFR-2013-title27-vol1-sec9-49.pdf"><span>27 CFR 9.49 - Central Delaware Valley.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-04-01</p> <p>... starting point of the following boundary description is the summit of Strawberry Hill, which is located in.... (2) Boundary Description: (i) From the summit of Strawberry Hill (475 feet) in a straight line to the... summit of Strawberry Hill (475 feet). [T.D. ATF-168, 49 FR 10117, Mar. 19, 1984, as amended by T.D. ATF...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title27-vol1/pdf/CFR-2012-title27-vol1-sec9-49.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title27-vol1/pdf/CFR-2012-title27-vol1-sec9-49.pdf"><span>27 CFR 9.49 - Central Delaware Valley.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-04-01</p> <p>... starting point of the following boundary description is the summit of Strawberry Hill, which is located in.... (2) Boundary Description: (i) From the summit of Strawberry Hill (475 feet) in a straight line to the... summit of Strawberry Hill (475 feet). [T.D. ATF-168, 49 FR 10117, Mar. 19, 1984, as amended by T.D. ATF...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title27-vol1/pdf/CFR-2011-title27-vol1-sec9-49.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title27-vol1/pdf/CFR-2011-title27-vol1-sec9-49.pdf"><span>27 CFR 9.49 - Central Delaware Valley.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-04-01</p> <p>... starting point of the following boundary description is the summit of Strawberry Hill, which is located in.... (2) Boundary Description: (i) From the summit of Strawberry Hill (475 feet) in a straight line to the... summit of Strawberry Hill (475 feet). [T.D. ATF-168, 49 FR 10117, Mar. 19, 1984, as amended by T.D. ATF...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=challenge+AND+women+AND+family+AND+business&id=ED465463','ERIC'); return false;" href="https://eric.ed.gov/?q=challenge+AND+women+AND+family+AND+business&id=ED465463"><span>We the Children: Meeting the Promises of the World Summit for Children.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Annan, Kofi A.</p> <p></p> <p>This abridged version of the Secretary-General's report to the United Nations General Assembly's Special Session on Children details the achievements of the 1990 World Summit for Children. Nearly 150 countries provided national progress reports of their implementation of goals set forth in the Summit and the 1989 Convention on the Rights of the…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=depending+AND+online+AND+technology&pg=5&id=EJ1015346','ERIC'); return false;" href="https://eric.ed.gov/?q=depending+AND+online+AND+technology&pg=5&id=EJ1015346"><span>A Bold New Math Class</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Khan, Salman; Slavitt, Elizabeth</p> <p>2013-01-01</p> <p>Summit San Jose is part of the Summit Public Schools network, a group of charter schools in California's Bay Area. In 2011, when Summit San Jose first opened its new high school with a cohort of 9th graders, the teachers decided to pilot Khan Academy. At the time, they had piloted their math resources and platform with five classrooms in Los…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED570437.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED570437.pdf"><span>2016 Personalized Learning & Student Success Summit: Summary from the NMC</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>New Media Consortium, 2016</p> <p>2016-01-01</p> <p>The New Media Consortium (NMC) hosted the Personalized Learning & Student Success Summit at SXSWedu on March 7-9 in Austin, Texas. The summit convened grantees and partners of the Postsecondary Strategy at the Bill & Melinda Gates Foundation and served as a call-to-action for education leaders to first imagine if and then commit to trying…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=The+AND+new+AND+economy&pg=5&id=ED536372','ERIC'); return false;" href="https://eric.ed.gov/?q=The+AND+new+AND+economy&pg=5&id=ED536372"><span>Community Colleges in the Evolving STEM Education Landscape: Summary of a Summit</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Olson, Steve; Labov, Jay B.</p> <p>2012-01-01</p> <p>The National Research Council (NRC) and National Academy of Engineering (NAE) have released a new report, "Community Colleges in the Evolving STEM Education Landscape: Summary of a Summit." Based on a national summit that was supported by the National Science Foundation and organized by the NRC and the NAE, the report highlights the importance of…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA487740','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA487740"><span>ORA User’s Guide 2008</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2008-07-01</p> <p>12 10 Stargate - Summit - Synopsis...Applications 13 10 Stargate - Summit - Synopsis 10.1 Story Background The data for this scenario is based on the Sci-Fi tv show, Stargate SG-1 and...all of the head Gou’ald in one fell swoop by inflitrating a summit and poisoning them all simultanously. With the help of Stargate Command and the</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED537332.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED537332.pdf"><span>It's Not a Matter of Time: Highlights from the 2011 Competency-Based Summit</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Sturgis, Chris; Patrick, Susan; Pittenger, Linda</p> <p>2011-01-01</p> <p>From Anchorage, Alaska, to Orlando, Florida, and from Gray, Maine, to Yuma, Arizona, one hundred competency-based innovators gathered at the Competency-Based Learning Summit in March 2011. Sponsored by the Council of Chief State School Officers (CCSSO) and the International Association for K-12 Online Learning (iNACOL), the Summit was developed in…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/EJ1079857.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/EJ1079857.pdf"><span>Communicating the Emerging Roles of Librarians to Teachers through a Collaborative K-12 and Higher Education Partnership</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Schroeder, Eileen E.; Fisher, Stacy</p> <p>2015-01-01</p> <p>In 2010 the Wisconsin Department of Public Instruction (DPI) responded to rapid changes in school libraries by convening the "Wisconsin School Library Summit: Envisioning 21st Century Learners and School Library Media Programs." Summit participants discussed the future of school libraries in Wisconsin. During the summit, several…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title27-vol1/pdf/CFR-2010-title27-vol1-sec9-49.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title27-vol1/pdf/CFR-2010-title27-vol1-sec9-49.pdf"><span>27 CFR 9.49 - Central Delaware Valley.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-04-01</p> <p>... starting point of the following boundary description is the summit of Strawberry Hill, which is located in.... (2) Boundary Description: (i) From the summit of Strawberry Hill (475 feet) in a straight line to the... summit of Strawberry Hill (475 feet). [T.D. ATF-168, 49 FR 10117, Mar. 19, 1984, as amended by T.D. ATF...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=world+AND+overpopulation&pg=5&id=ED338388','ERIC'); return false;" href="https://eric.ed.gov/?q=world+AND+overpopulation&pg=5&id=ED338388"><span>The State of the World's Children, 1991.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Grant, James P.</p> <p></p> <p>The World Summit for children was held at the United Nations, New York, on September 30, 1990. The summit set child health goals to be achieved by the year 2000, and offered strategies and guiding principles for achieving the goals. The summit proposed a new ethic for children which called for children's needs to be given high priority in the…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=Dan&pg=5&id=ED509273','ERIC'); return false;" href="https://eric.ed.gov/?q=Dan&pg=5&id=ED509273"><span>Test Equity for Individuals Who Are Deaf or Hard of Hearing. PEPNet Test Equity Summit</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>PEPNet-West, 2010</p> <p>2010-01-01</p> <p>This paper presents the highlights of the 2008 Test Equity Summit held in Bloomfield, Colorado last August 6-8, 2008. The 2008 Test Equity Summit convened by the Postsecondary Education Programs Network (PEPNet) identified and examined problems, challenges, and issues that academic and psychoeducational tests pose for individuals who are deaf or…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED523542.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED523542.pdf"><span>Restoring the Trust in Native Education. Annual NIEA Legislative Summit (14th, February 7-9, 2011). Briefing Papers</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>National Indian Education Association, 2011</p> <p>2011-01-01</p> <p>Several briefing papers were presented during the 14th Annual National Indian Education Association (NIEA) Legislative Summit. This briefing book contains the following papers presented during the summit: (1) Restoring the Trust in Native Education; (2) NIEA Legislative Priorities for 2011: "Talking Points"; (3) Reauthorization of the…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/pp/1750/chapters/pp2008-1750_chapter06.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/pp/1750/chapters/pp2008-1750_chapter06.pdf"><span>Seismicity and infrasound associated with explosions at Mount St. Helens, 2004-2005: Chapter 6 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Moran, Seth C.; McChesney, Patrick J.; Lockhart, Andrew B.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.</p> <p>2008-01-01</p> <p>Six explosions occurred during 2004-5 in association with renewed eruptive activity at Mount St. Helens, Washington. Of four explosions in October 2004, none had precursory seismicity and two had explosion-related seismic tremor that marked the end of the explosion. However, seismicity levels dropped following each of the October explosions, providing the primary instrumental means for explosion detection during the initial vent-clearing phase. In contrast, explosions on January 16 and March 8, 2005, produced noticeable seismicity in the form of explosion-related tremor, infrasonic signals, and, in the case of the March 8 explosion, an increase in event size ~2 hours before the explosion. In both 2005 cases seismic tremor appeared before any infrasonic signals and was best recorded on stations located within the crater. These explosions demonstrated that reliable explosion detection at volcanoes like Mount St. Helens requires seismic stations within 1-2 km of the vent and stations with multiple acoustic sensors.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2011-09-12/pdf/2011-23248.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2011-09-12/pdf/2011-23248.pdf"><span>76 FR 56224 - Agency Information Collection Activities; Proposed Collection, Comments Requested: Records and...</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2011-09-12</p> <p>..., and Users Licensed Under Title 18 U.S.C. Chapter 40 Explosives ACTION: 30-Day Notice of Information... Disposition By Explosives Importers, Manufacturers, Dealers, and Users Licensed Under Title 18 U.S.C... under 18 U.S.C. chapter 40 Explosives. The records are used to show where and to whom explosive...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018BVol...80...21R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018BVol...80...21R"><span>Constraints on the geomorphological evolution of the nested summit craters of Láscar volcano from high spatio-temporal resolution TerraSAR-X interferometry</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Richter, Nicole; Salzer, Jacqueline Tema; de Zeeuw-van Dalfsen, Elske; Perissin, Daniele; Walter, Thomas R.</p> <p>2018-03-01</p> <p>Small-scale geomorphological changes that are associated with the formation, development, and activity of volcanic craters and eruptive vents are often challenging to characterize, as they may occur slowly over time, can be spatially localized, and difficult, or dangerous, to access. Using high-spatial and high-temporal resolution synthetic aperture radar (SAR) imagery collected by the German TerraSAR-X (TSX) satellite in SpotLight mode in combination with precise topographic data as derived from Pléiades-1A satellite data, we investigate the surface deformation within the nested summit crater system of Láscar volcano, Chile, the most active volcano of the central Andes. Our aim is to better understand the structural evolution of the three craters that comprise this system, to assess their physical state and dynamic behavior, and to link this to eruptive activity and associated hazards. Using multi-temporal SAR interferometry (MT-InSAR) from ascending and descending orbital geometries, we retrieve the vertical and east-west components of the displacement field. This time series indicates constant rates of subsidence and asymmetric horizontal displacements of all summit craters between June 2012 and July 2014, as well as between January 2015 and March 2017. The vertical and horizontal movements that we observe in the central crater are particularly complex and cannot be explained by any single crater formation mechanism; rather, we suggest that short-term activities superimposed on a combination of ongoing crater evolution processes, including gravitational slumping, cooling and compaction of eruption products, as well as possible piston-like subsidence, are responsible for the small-scale geomorphological changes apparent in our data. Our results demonstrate how high-temporal resolution synthetic aperture radar interferometry (InSAR) time series can add constraints on the geomorphological evolution and structural dynamics of active crater and vent systems at volcanoes worldwide.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMNH53A1731B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMNH53A1731B"><span>Deformation signals from InSAR time series analysis related to the 2007 and 2011 east rift zone intrusions at Kilauea Volcano, Hawaii</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baker, S.; Amelung, F.</p> <p>2011-12-01</p> <p>Located on the Big Island of Hawaii, Kilauea volcano is one of the most active volcanoes on Earth with continuous eruptive activity since 1983. The eruptive activity is predominately from the Pu'u O'o vent within the east rift zone, but periodic intrusions occur in the upper east rift zone between the summit and Pu'u O'o. These intrusions occur as dikes typically accompanied by fissure openings and eruptions of small volumes of lava. Interferometric synthetic aperture radar (InSAR) provides surface displacement measurements showing how the ground moves before, during, and after these intrusions. Given the recent increase in the number of active or planned SAR satellites and the more frequent repeat-pass times, InSAR is proving to be a valuable monitoring tool for volcanic hazards. Using data from Radarsat-1, Envisat, ALOS, and TerraSAR-X satellites, we generate line-of-sight InSAR time series using the small baseline subset (SBAS) which provides dense spatial and temporal coverage at Kilauea covering the 17 June 2007 and 5 March 2011 intrusions. For these two events, the summit caldera area switches from deflation to inflation months to years before both intrusions, and just prior to the intrusions we observe increased rates of inflation accompanied by elevated seismic activity in the upper east rift zone. Observations of the intrusion relate surface displacement and the response of the summit caldera area provide insight into the shallow magmatic system and the connectivity of the system. By combining InSAR time series with other geophysical data sets (such as seismic or GPS), we obtain more details about the associated hazard and a better understanding of the time-dependent relationship between what we are measuring and the controlling processes at the volcano.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18799993','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18799993"><span>Mt. Whitney: determinants of summit success and acute mountain sickness.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wagner, Dale R; D'Zatko, Kim; Tatsugawa, Kevin; Murray, Ken; Parker, Daryl; Streeper, Tim; Willard, Kevin</p> <p>2008-10-01</p> <p>The aim of this study was to determine the prevalence of summit success and acute mountain sickness (AMS) on Mt. Whitney (4419 m) and to identify variables that contribute to both. Hikers (N = 886) attempting the summit were interviewed at the trailhead upon their descent. Questionnaires included demographic and descriptive data, acclimatization and altitude history, and information specific to the ascent. The Lake Louise Self-Assessment Score was used to make a determination about the occurrence of AMS. Logistic regression techniques were used to calculate odds ratios (OR) for AMS and summit success. Forty-three percent of the sample met the criteria for AMS, and 81% reached the summit. The odds of experiencing AMS were reduced with increases in age (adjusted 10-yr OR = 0.78; P < 0.001), number of hours spent above 3000 m in the 2 wk preceding the ascent (adjusted 24-h OR = 0.71; P < 0.001), and for females (OR = 0.68; P = 0.02). Climbers who had a history of AMS (OR = 1.41; P = 0.02) and those taking analgesics (OR = 2.39; P < 0.001) were more likely to experience AMS. As climber age increased, the odds of reaching the summit decreased (adjusted 10-yr OR = 0.75; P < 0.001). However, increases in the number of hours per week spent training (adjusted 5-h OR = 1.24; P = 0.05), rate of ascent (adjusted 50 m x h(-1) OR = 1.13; P = 0.04), and previous high-altitude record (adjusted 500 m OR = 1.26; P < 0.001) were all associated with increased odds for summit success. A high percentage of trekkers reached the summit despite having symptoms of AMS.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70023280','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70023280"><span>Implications for eruptive processes as indicated by sulfur dioxide emissions from Kilauea Volcano, Hawai'i, 1979-1997</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Sutton, A.J.; Elias, T.; Gerlach, T.M.; Stokes, J.B.</p> <p>2001-01-01</p> <p>Kı̄lauea Volcano, Hawai‘i, currently hosts the longest running SO2 emission-rate data set on the planet, starting with initial surveys done in 1975 by Stoiber and his colleagues. The 17.5-year record of summit emissions, starting in 1979, shows the effects of summit and east rift eruptive processes, which define seven distinctly different periods of SO2 release. Summit emissions jumped nearly 40% with the onset (3 January 1983) of the Pu`u `Ō`ō-Kūpaianaha eruption on the east rift zone (ERZ). Summit SO2 emissions from Kı̄lauea showed a strong positive correlation with short-period, shallow, caldera events, rather than with long-period seismicity as in more silicious systems. This correlation suggests a maturation process in the summit magma-transport system from 1986 through 1993. During a steady-state throughput-equilibrium interval of the summit magma reservoir, integration of summit-caldera and ERZ SO2 emissions reveals an undegassed volume rate of effusion of 2.1×105 m3/d. This value corroborates the volume-rate determined by geophysical methods, demonstrating that, for Kı̄lauea, SO2 emission rates can be used to monitor effusion rate, supporting and supplementing other, more established geophysical methods. For the 17.5 years of continuous emission rate records at Kı̄lauea, the volcano has released 9.7×106 t (metric tonnes) of SO2, 1.7×106 t from the summit and 8.0×106 t from the east rift zone. On an annual basis, the average SO2 release from Kı̄lauea is 4.6×105 t/y, compared to the global annual volcanic emission rate of 1.2×107 t/y.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26808817','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26808817"><span>Internet-Delivered Disease Management for Recurrent Depression: A Multicenter Randomized Controlled Trial.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kordy, Hans; Wolf, Markus; Aulich, Kai; Bürgy, Martin; Hegerl, Ulrich; Hüsing, Johannes; Puschner, Bernd; Rummel-Kluge, Christine; Vedder, Helmut; Backenstrass, Matthias</p> <p>2016-01-01</p> <p>Strategies to improve the life of patients suffering from recurrent major depression have a high relevance. This study examined the efficacy of 2 Internet-delivered augmentation strategies that aim to prolong symptom-free intervals. Efficacy was tested in a 3-arm, multicenter, open-label, evaluator-blind, randomized controlled trial. Upon discharge from inpatient mental health care, 232 adults with 3 or more major depressive episodes were randomized to 1 of 2 intervention groups (SUMMIT or SUMMIT-PERSON) or to treatment as usual (TAU) alone. Over 12 months, participants in both intervention arms received, in addition to TAU, intense monitoring via e-mail or a smartphone, including signaling of upcoming crises, assistance with personal crisis management, and facilitation of early intervention. SUMMIT-PERSON additionally offered regular expert chats. The primary outcome was 'well weeks', i.e. weeks with at most mild symptoms assessed by the Longitudinal Interval Follow-Up Evaluation, during 24 months after the index treatment. SUMMIT compared to TAU reduced the time with an unwell status (OR 0.48; 95% CI 0.23-0.98) through faster transitions from unwell to well (OR 1.44; 95% CI 0.83-2.50) and slower transitions from well to unwell (OR 0.69; 95% CI 0.44-1.09). Contrary to the hypothesis, SUMMIT-PERSON was not superior to either SUMMIT (OR 0.77; 95% CI 0.38-1.56) or TAU (OR 0.62; 95% CI 0.31-1.24). The efficacy of SUMMIT was strongest 8 months after the intervention. The fully automated Internet-delivered augmentation strategy SUMMIT has the potential to improve TAU by reducing the lifelong burden of patients with recurrent depression. The fact that the effects wear off suggests a time-unlimited extension. © 2016 S. Karger AG, Basel.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70035730','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70035730"><span>Magma degassing triggered by static decompression at Kīlauea Volcano, Hawai‘i</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Poland, Michael P.; Jeff, Sutton A.; Gerlach, Terrence M.</p> <p>2009-01-01</p> <p>During mid-June 2007, the summit of Kīlauea Volcano, Hawai‘i, deflated rapidly as magma drained from the subsurface to feed an east rift zone intrusion and eruption. Coincident with the deflation, summit SO2 emission rates rose by a factor of four before decaying to background levels over several weeks. We propose that SO2 release was triggered by static decompression caused by magma withdrawal from Kīlauea's shallow summit reservoir. Models of the deflation suggest a pressure drop of 0.5–3 MPa, which is sufficient to trigger exsolution of the observed excess SO2 from a relatively small volume of magma at the modeled source depth beneath Kīlauea's summit. Static decompression may also explain other episodes of deflation accompanied by heightened gas emission, including the precursory phases of Kīlauea's 2008 summit eruption. Hazards associated with unexpected volcanic gas emission argue for increased awareness of magma reservoir pressure fluctuations.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/5698251-geology-kilauea-volcano','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/5698251-geology-kilauea-volcano"><span>Geology of Kilauea volcano</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Moore, R.B.; Trusdell, F.A.</p> <p>1993-08-01</p> <p>This paper summarizes studies of the structure, stratigraphy, petrology, drill holes, eruption frequency, and volcanic and seismic hazards of Kilauea volcano. All the volcano is discussed, but the focus is on its lower east rift zone (LERZ) because active exploration for geothermal energy is concentrated in that area. Kilauea probably has several separate hydrothermal-convection systems that develop in response to the dynamic behavior of the volcano and the influx of abundant meteoric water. Important features of some of these hydrothermal-convection systems are known through studies of surface geology and drill holes. Observations of eruptions during the past two centuries, detailedmore » geologic mapping, radiocarbon dating, and paleomagnetic secular-variation studies indicate that Kilauea has erupted frequently from its summit and two radial rift zones during Quaternary time. Petrologic studies have established that Kilauea erupts only tholeiitic basalt. Extensive ash deposits at Kilauea's summit and on its LERZ record locally violent, but temporary, disruptions of local hydrothermal-convection systems during the interaction of water or steam with magma. Recent drill holes on the LERZ provide data on the temperatures of the hydrothermal-convection systems, intensity of dike intrusion, porosity and permeability, and an increasing amount of hydrothermal alteration with depth. The prehistoric and historic record of volcanic and seismic activity indicates that magma will continue to be supplied to deep and shallow reservoirs beneath Kilauea's summit and rift zones and that the volcano will be affected by eruptions and earthquakes for many thousands of years. 71 refs., 2 figs.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70022569','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70022569"><span>A model for the magmatic-hydrothermal system at Mount Rainier, Washington, from seismic and geochemical observations</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Moran, S.C.; Zimbelman, D.R.; Malone, S.D.</p> <p>2000-01-01</p> <p>Mount Rainier is one of the most seismically active volcanoes in the Cascade Range, with an average of one to two high-frequency volcano-tectonic (or VT) earthquakes occurring directly beneath the summit in a given month. Despite this level of seismicity, little is known about its cause. The VT earthquakes occur at a steady rate in several clusters below the inferred base of the Quaternary volcanic edifice. More than half of 18 focal mechanisms determined for these events are normal, and most stress axes deviate significantly from the regional stress field. We argue that these characteristics are most consistent with earthquakes in response to processes associated with circulation of fluids and magmatic gases within and below the base of the edifice. Circulation of these fluids and gases has weakened rock and reduced effective stress to the point that gravity-induced brittle fracture, due to the weight of the overlying edifice, can occur. Results from seismic tomography and rock, water, and gas geochemistry studies support this interpretation. We combine constraints from these studies into a model for the magmatic system that includes a large volume of hot rock (temperatures greater than the brittle-ductile transition) with small pockets of melt and/or hot fluids at depths of 8-18 km below the summit. We infer that fluids and heat from this volume reach the edifice via a narrow conduit, resulting in fumarolic activity at the summit, hydrothermal alteration of the edifice, and seismicity.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70017417','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70017417"><span>Geology of kilauea volcano</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Moore, R.B.; Trusdell, F.A.</p> <p>1993-01-01</p> <p>This paper summarizes studies of the structure, stratigraphy, petrology, drill holes, eruption frequency, and volcanic and seismic hazards of Kilauea volcano. All the volcano is discussed, but the focus is on its lower cast rift zone (LERZ) because active exploration for geothermal energy is concentrated in that area. Kilauea probably has several separate hydrothermal-convection systems that develop in response to the dynamic behavior of the volcano and the influx of abundant meteoric water. Important features of some of these hydrothermal-convection systems are known through studies of surface geology and drill holes. Observations of eruptions during the past two centuries, detailed geologic mapping, radiocarbon dating, and paleomagnetic secular-variation studies indicate that Kilauea has erupted frequently from its summit and two radial rift zones during Quaternary time. Petrologic studies have established that Kilauea erupts only tholeiitic basalt. Extensive ash deposits at Kilauea's summit and on its LERZ record locally violent, but temporary, disruptions of local hydrothermal-convection systems during the interaction of water or steam with magma. Recent drill holes on the LERZ provide data on the temperatures of the hydrothermal-convection systems, intensity of dike intrusion, porosity and permeability, and an increasing amount of hydrothermal alteration with depth. The prehistoric and historic record of volcanic and seismic activity indicates that magma will continue to be supplied to deep and shallow reservoirs beneath Kilauea's summit and rift zones and that the volcano will be affected by eruptions and earthquakes for many thousands of years. ?? 1993.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70046828','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70046828"><span>A mantle-driven surge in magma supply to Kīlauea Volcano during 2003--2007</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Poland, Michael P.; Miklius, Asta; Sutton, A. Jeff; Thornber, Carl R.</p> <p>2012-01-01</p> <p>The eruptive activity of a volcano is fundamentally controlled by the rate of magma supply. At Kīlauea Volcano, Hawai‘i, the rate of magma rising from a source within Earth’s mantle, through the Hawaiian hotspot, was thought to have been relatively steady in recent decades. Here we show that the magma supply to Kīlauea at least doubled during 2003–2007, resulting in dramatic changes in eruptive activity and the formation of new eruptive vents. An initial indication of the surge in supply was an increase in CO2 emissions during 2003–2004, combined with the onset of inflation of Kīlauea’s summit, measured using the Global Positioning System and interferometric synthetic aperture radar. Inflation was not limited to the summit magma reservoirs, but was recorded as far as 50 km from the summit, implying the existence of a connected magma system over that distance. We also record increases in SO2 emissions, heightened seismicity, and compositional and temperature variations in erupted lavas. The increase in the volume of magma passing through and stored within Kīlauea, coupled with increased CO2 emissions, indicate a mantle source for the magma surge. We suggest that magma supply from the Hawaiian hotspot can vary over timescales of years, and that CO2 emissions could be a valuable aid for assessing variations in magma supply at Kīlauea and other volcanoes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29086516','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29086516"><span>American Society of Clinical Oncology Summit on Addressing Obesity Through Multidisciplinary Provider Collaboration: Key Findings and Recommendations for Action.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ligibel, Jennifer A; Alfano, Catherine M; Hershman, Dawn L; Merrill, Janette K; Basen-Engquist, Karen; Bloomgarden, Zachary T; Demark-Wahnefried, Wendy; Dixon, Suzanne; Hassink, Sandra G; Jakicic, John M; Morton, John Magaña; Okwuosa, Tochi M; Powell-Wiley, Tiffany M; Rothberg, Amy E; Stephens, Mark; Streett, Sarah E; Wild, Robert A; Westman, Eric A; Williams, Ronald J; Wollins, Dana S; Hudis, Clifford A</p> <p>2017-11-01</p> <p>Given the increasing evidence that obesity increases the risk of developing and dying from malignancy, the American Society of Clinical Oncology (ASCO) launched an Obesity Initiative in 2013 that was designed to increase awareness among oncology providers and the general public of the relationship between obesity and cancer and to promote research in this area. Recognizing that the type of societal change required to impact the obesity epidemic will require a broad-based effort, ASCO hosted the "Summit on Addressing Obesity through Multidisciplinary Collaboration" in 2016. This meeting was held to review current challenges in addressing obesity within the respective health care provider communities and to identify priorities that would most benefit from a collective and cross-disciplinary approach. Efforts focused on four key areas: provider education and training; public education and activation; research; and policy and advocacy. Summit attendees discussed current challenges in addressing obesity within their provider communities and identified priorities that would most benefit from multidisciplinary collaboration. A synopsis of recommendations to facilitate future collaboration, as well as examples of ongoing cooperative efforts, provides a blueprint for multidisciplinary provider collaboration focused on obesity prevention and treatment. © 2017 The Obesity Society.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003JGRB..108.2028H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003JGRB..108.2028H"><span>Mixing of magmatic volatiles with groundwater and interaction with basalt on the summit of Kilauea Volcano, Hawaii</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hurwitz, Shaul; Goff, Fraser; Janik, Cathy J.; Evans, William C.; Counce, Dale A.; Sorey, Michael L.; Ingebritsen, Steven E.</p> <p>2003-01-01</p> <p>We interpret new chemical and isotopic data from samples collected between October 1998 and March 2002 from the NSF well (also called the Keller well), the only deep well on the summit of Kilauea Volcano, Hawaii. Sample collection followed cleaning of the well, which renewed access to the hydrothermal system very close to the loci of magmatic and fumarolic activity. The chemical and isotopic compositions of the new samples differ remarkably from data published previously. On the basis of the S/Cl ratio and carbon and helium isotopes we conclude that the thermal fluids formed by condensation of magmatic gas into shallow meteoric groundwater. Gas condensation was followed by a complex pattern of basalt dissolution accompanied by an increase of fluid pH and precipitation of secondary minerals. Geochemical modeling and geothermometry imply that the fluids equilibrated with an assemblage of secondary minerals at temperatures between 90 and 140°C. The significantly different chemical composition of the NSF well fluids from that of springs along the southern coast of the island indicates that mass transport from the summit region toward the lower flanks of the volcano is limited.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4770841','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4770841"><span>The National LGBT Cancer Action Plan: A White Paper of the 2014 National Summit on Cancer in the LGBT Communities</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Margolies, Liz; Sigurdsson, Hrafn Oli; Walland, Jonathan; Radix, Asa; Rice, David; Buchting, Francisco O.; Sanchez, Nelson F.; Bare, Michael G.; Boehmer, Ulrike; Cahill, Sean; Griebling, Tomas L.; Bruessow, Diane; Maingi, Shail</p> <p>2016-01-01</p> <p>Abstract Despite growing social acceptance of lesbians, gay men, bisexuals, and transgender (LGBT) persons and the extension of marriage rights for same-sex couples, LGBT persons experience stigma and discrimination, including within the healthcare system. Each population within the LGBT umbrella term is likely at elevated risk for cancer due to prevalent, significant cancer risk factors, such as tobacco use and human immunodeficiency virus infection; however, cancer incidence and mortality data among LGBT persons are lacking. This absence of cancer incidence data impedes research and policy development, LGBT communities' awareness and activation, and interventions to address cancer disparities. In this context, in 2014, a 2-day National Summit on Cancer in the LGBT Communities was convened by a planning committee for the purpose of accelerating progress in identifying and addressing the LGBT communities' concerns and needs in the spheres of cancer research, clinical cancer care, healthcare policy, and advocacy for cancer survivorship and LGBT health equity. Summit participants were 56 invited persons from the United States, United Kingdom, and Canada, representatives of diverse identities, experiences, and knowledge about LGBT communities and cancer. Participants shared lessons learned and identified gaps and remedies regarding LGBT cancer concerns across the cancer care continuum from prevention to survivorship. This white paper presents background on each of the Summit themes and 16 recommendations covering the following: sexual orientation and gender identity data collection in national and state health surveys and research on LGBT communities and cancer, the clinical care of LGBT persons, and the education and training of healthcare providers.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008Geomo.100..312R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008Geomo.100..312R"><span>Accordant summit heights, summit levels and the origin of the ``upper denudation level'' in the Serra do Mar (SE-Brazil, São Paulo): A study of hillslope forms and processes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Römer, Wolfgang</p> <p>2008-08-01</p> <p>In southern São Paulo the Serra do Mar is characterized by three distinct terrain types: 1) highly dissected areas with closely spaced ridges and accordant summit heights; 2) multiconvex hills; and 3) terrains with highly elevated watershed areas, irregular summit heights, and locally subdued relief. The development of this landscape is considered to be the result of the Cenozoic block-faulting and of the influences that are exerted by the differing lithological and structural setting of block-faulted compartments on weathering and erosion processes. In areas characterized by pronounced accordant summits the close coincidence between hillslope angle and the angle of limiting stability against landsliding points to a close adjustment of hillslope gradients and the mechanical properties of the regolith. The relative height of the hillslopes is functionally related to the spacing of the valleys and the gradient of the hillslopes. In areas with a regular spacing of v-shaped valleys and uniform rocks, this leads to the intersection of valley-side slopes in summits and ridges at a certain elevation. This elevation is determined by the length and steepness of the valley-side slopes. Therefore, the heights of the summits are geometrically constrained and are likely to indicate the upper limit of summit heights or an "upper denudation level" that is adjusted by hillslope processes to the incising streams. Accordant summit heights of this type are poor indicators of formerly more extensive denudation surfaces as it is also likely that they are a result of the long-term adjustment of hillslopes to river incision. The steep mountain flanks of block-faulted compartments on the other hand, comprise regolith-covered hillslopes that are closely adjusted to the maximum stable gradient as well as rock-slopes that are controlled by the rock-mass strength. Their summits are usually not accommodated into uniform summit levels. Highly elevated watershed areas exhibiting a subdued relief are detached from the base level response. On granitoid rocks these areas are often characterized by the rocky hills and domal rock outcrops. However, differences in the elevation of interfluves and summits between rocks of differing resistance and in the elevation of lithologically distinct individual fault-blocks imply that long-term weathering and erosion has transformed and lowered these landscapes. Therefore, these areas cannot be interpreted as a remnant of a pre-uplift topography and it appears to be unlikely that the height of the summits correlates with formerly more widespread planation surfaces in the far hinterland. The studies indicate that concepts such as the parallel retreat of hillslopes cannot account for the observed differences in the landscape. It is suggested that the Serra do Mar is consumed from the Atlantic and the inland side by spatially non-uniform developmental states. These states are determined by local differences in the coupling and distance to the regional base level and sea-level or are due to lithological and structural controls between and within the block-faulted compartments.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.V33F..03G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.V33F..03G"><span>Parameterization of strombolian explosions: constraint from simultaneous physical and geophysical measurements (Invited)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>gurioli, L.; Harris, A. J.</p> <p>2013-12-01</p> <p>Strombolian activity is the most common type of explosive eruption (by frequency) experienced by Earth's volcanoes. It is commonly viewed as consisting of a succession of short discrete explosions where fragments of incandescent magma are ejected a few tens to hundreds meters into the air. This kind of activity is generally restricted to basaltic or basaltic-andesitic magmas because these systems have the sufficiently low viscosities so as to allow gas coalescence and decoupled slug ascent. Mercalli (1907) proposed one of the first formal classifications of explosive activity based on the character of the erupted products and descriptions of case-type eruptions. Later, Walker (1973) devised a classification based on grain size and dispersion, within which strombolian explosions formed the low-to-middle end of the classification. Other classifications have categorized strombolian activity on the basis of erupted magnitude and/or intensity, such as Newhall and Self's (1982) Volcanic Explosivity Index (VEI). Classification can also be made on the basis of explosion mechanism, where strombolian eruptions have become associated with bursting of large gas bubbles, as opposed to release of locked in bubble populations in rapidly ascending magma that feed sustained fountains. Finally, strombolian eruptions can be defined on the basis of geophysical metrics for the explosion source and plume ascent dynamics. Recently, the volcanology community has begun to discuss the difficulty of actually placing strombolian explosions within the compartments defined by each scheme. New sampling strategies in active strombolian volcanic fields have allowed us to parameterize these mildly explosive events both physically and geophysically. Our data show that individual 'normal' and "major" explosions at Stromboli are extremely small, meaning that the classical deposit-based classification thresholds need to be reduced, or a new category defined, if the 'strombolian' eruption style at Stromboli, and other volcanoes like it, are to plot in the strombolian fields of deposit-based classifications. We also quenched a number of bombs soon explosion at Stromboli. This enabled us to quantify the degassing history and rheology of the magma(s) resident in the shallow, near-surface, system. The different textural facies observed in these bombs showed that fresh magma, mingled with partially or completely degassed, oxidized, re-crystallized, evolved and high viscosity magma, was ejected. The degassed magma appears to sit at the top of the conduit, playing only a passive role in the explosive process. Our best model, is that the degassed, oxidized magma forms a plug, or rheologically defined layer, at the top of the conduit, through which the fresh magma bursts. Integration of geophysical measurements with sample analyses, indicates that popular (bubble-bursting) models may not fit this case, thus also changeling the model-based definition of this eruption type.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009JVGR..182..123B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009JVGR..182..123B"><span>Chronology of the 2007 eruption of Stromboli and the activity of the Scientific Synthesis Group</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barberi, Franco; Civetta, Lucia; Rosi, Mauro; Scandone, Roberto</p> <p>2009-05-01</p> <p>On 27 February 2007, at 12.49 GMT, a new eruption of Stromboli took place with the effusion of a lava flow from a fracture cutting the flank of the NE cone, which rapidly reached the sea. The eruption had been heralded by an increase in the amplitude of tremor and flank movement since at least the 14th of February. Short-term precursors were an increase in the rate of occurrence of small landslides within the "Sciara del Fuoco" scar on the North-western flank of the volcano. A new effusive vent opened at 18.30 GMT on the Sciara del Fuoco at an height of 400 m asl. The new lava emission caused the sudden termination of the summit flow and initiated a period of non-stationary lava outpouring which ended on 2 April, 2007. The eruption has been characterized by a rapid decrease in the eruption rate after the first days and subsequently by episodic pulse increases. On the 15th of March, the increase in lava outpouring, monitored by a thermal camera, heralded by 9 min the occurrence of a violent paroxysmal explosion with the formation of an impulsive eruption column and the emission of small pumices mingled with black scoriae. The pumice had a bulk composition similar to that of the lava and of the black scoriae, but with a distinct lower content of phenocrysts. A similar feature has been repeatedly observed during the major explosive paroxysms of Stromboli. Short term precursors of the paroxysm were recorded by strainmeter and tiltmeter stations. The volcano monitoring activity has been made by a joint team of researchers from the INGV sections of Catania, Napoli, Palermo and Rome, along with researchers from the Universities of Florence, Pisa, Roma Tre, and Palermo. The scientific activity was coordinated by a Synthesis Group made up by scientists responsible for the different monitoring techniques of INGV and Universities and by the volcanic experts of Commissione Nazionale Grandi Rischi of the Prime Minister Office (Civil Protection Department). The group made a daily evaluation of the state of the volcano and transmitted its recommendations to the Civil Protection Department (DPC). Several prevention measures were adopted by DPC, the main of which were the evacuation of the coast zone when strong acceleration of the Sciara del Fuoco slope motion (occurred twice) could led to a dangerous tsunami by flank collapse (as last occurred on 30 December 2002) and four days before the 15 March paroxysm when access was prohibited to the part of the volcano above 290 m asl.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24854223','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24854223"><span>Biotransformation of explosives by Reticulitermes flavipes--associated termite Endosymbionts.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Indest, Karl J; Eaton, Hillary L; Jung, Carina M; Lounds, Caly B</p> <p>2014-01-01</p> <p>Termites have an important role in the carbon and nitrogen cycles despite their reputation as destructive pests. With the assistance of microbial endosymbionts, termites are responsible for the conversion of complex biopolymers into simple carbon substrates. Termites also rely on endosymbionts for fixing and recycling nitrogen. As a result, we hypothesize that termite bacterial endosymbionts are a novel source of metabolic pathways for the transformation of nitrogen-rich compounds like explosives. Explosives transformation capability of termite (Reticulitermes flavipes)-derived endosymbionts was determined in media containing the chemical constituents nitrotriazolone (NTO) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) that comprise new insensitive explosive formulations. Media dosed with 40 µg/ml of explosive was inoculated with surface-sterilized, macerated termites. Bacterial isolates capable of explosives transformation were characterized by 16S rRNA sequencing. Termite-derived enrichment cultures demonstrated degradation activity towards the explosives NTO, RDX, as well as the legacy explosive 2,4,6-trinitrotoluene (TNT). Three isolates with high similarity to the Enterobacteriaceae(Enterobacter, Klebsiella) were able to transform TNT and NTO within 2 days, while isolates with high similarity to Serratia marcescens and Lactococcus lactis were able to transform RDX. Termite endosymbionts harbor a range of metabolic activities and possess unique abilities to transform nitrogen-rich explosives. © 2014 S. Karger AG, Basel.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=phi&pg=5&id=EJ751111','ERIC'); return false;" href="https://eric.ed.gov/?q=phi&pg=5&id=EJ751111"><span>How Well Has NCLB Worked? How Do We Get the Revisions We Want?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Lewis, Anne C.</p> <p>2007-01-01</p> <p>In this article, the author presents a description of Phi Delta Kappa International's 2006 Summit on Public Education. The 2006 Summit opened with a stimulating panel discussion on the hottest topic in education--the No Child Left Behind Act. The Summit's emphasis on NCLB had a clear purpose--to stimulate their members to become involved in the…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED519725.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED519725.pdf"><span>Supporting and Staffing High-Needs Schools: Recommendations from South Carolina's National Board Certified Teachers[R</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Berry, Barnett; Rasberry, Melissa; Byrd, Ann</p> <p>2007-01-01</p> <p>On August 5, 2006, more than 300 South Carolina National Board Certified Teachers[R] (NBCTs) assembled in Columbia at a policy summit to address the vexing problem of recruiting and retaining accomplished teachers in high-needs schools. Before this summit, the NBCTs read a number of background papers and research summaries. During the summit, they…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2011-01-05/pdf/2010-33200.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2011-01-05/pdf/2010-33200.pdf"><span>76 FR 550 - Second National Bed Bug Summit; Notice of Public Meeting</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2011-01-05</p> <p>... ENVIRONMENTAL PROTECTION AGENCY [EPA-HQ-OPP-2009-0190; FRL-8858-4] Second National Bed Bug Summit... planning the second National Bed Bug Summit to be held February 1 and 2, 2011, on the topic of the bed bug resurgence in the United States. The goal of this meeting is to review the current bed bug problem and...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <div class="footer-extlink text-muted" style="margin-bottom:1rem; text-align:center;">Some links on this page may take you to non-federal websites. 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