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1

Earthquakes at Loihi Submarine Volcano and the Hawaiian Hot Spot  

Microsoft Academic Search

Loihi is an active submarine volcano located 35 km south of the island of Hawaii and may eventually grow to be the next and southernmost island in the Hawaiian chain. The Hawaiian Volcano Observatory recorded two major earthquake swarms located there in 1971-1972 and 1975 which were probably associated with submarine eruptions or intrusions. The swarms were located very close

Fred W. Klein

1982-01-01

2

Earthquakes at Loihi submarine volcano and the Hawaiian hot spot  

Microsoft Academic Search

Loihi is an active submarine volcano located 35 km south of the island of Hawaii and may eventually grow to be the next and southernmost island in the Hawaiian chain. The Hawaiian Volcano Observatory recorded two major earthquake swarms located there in 1971-1972 and 1975 which were probably associated with submarine eruptions or intrusions. The swarms were located very close

Fred W. Klein

1982-01-01

3

Submarine Volcanoes in Arctic Ocean Surprise Scientists  

NSDL National Science Digital Library

Until now, geoscientists believed that spreading ridges under the Arctic Ocean were too slow-spreading and cool to vent molten rock. An article published this month in Nature details sonar data revealing two young volcanoes under Arctic waters. Dr. Marago H. Edwards of the University of Hawaii led the exploration team in which civilian scientists worked in cooperation with the Navy, using a nuclear submarine to take sonar readings of the ocean floor. A submarine was employed because the ice cover makes the Arctic seafloor unviewable by satellites and difficult for ships bearing seismic instruments to navigate. The two volcanoes were found at the Gakkel Ridge, the Earth's slowest spreading mid-ocean ridge. During August and September of 2001, Russian icebreakers and Mir submersibles will be employed to investigate the volcanoes, taking rock samples and looking for organisms living at the volcanic vents. This week's In the News takes a closer look at this discovery.

Sanders, Hilary C.

2001-01-01

4

Long-term explosion records from two erupting submarine volcanoes in the Mariana and Tonga island-arcs  

Microsoft Academic Search

Records of explosive activity longer than a few weeks are rare for subaerial volcanoes, and nonexistent for submarine volcanoes. From February 2008 to February 2009, we recorded a year long, continuous acoustic and volcanic plume record from NW Rota-1, an erupting submarine volcano located within the Mariana Arc. From December 2008 to May 2009, we also obtained acoustic records of

R. P. Dziak; R. W. Embley; E. T. Baker; W. W. Chadwick; J. Resing; H. Matsumoto; S. L. Walker; D. R. Bohnenstiehl; H. Klink

2009-01-01

5

Voluminous submarine lava flows from Hawaiian volcanoes  

SciTech Connect

The GLORIA long-range sonar imaging system has revealed fields of large lava flows in the Hawaiian Trough east and south of Hawaii in water as deep as 5.5 km. Flows in the most extensive field (110 km long) have erupted from the deep submarine segment of Kilauea's east rift zone. Other flows have been erupted from Loihi and Mauna Loa. This discovery confirms a suspicion, long held from subaerial studies, that voluminous submarine flows are erupted from Hawaiian volcanoes, and it supports an inference that summit calderas repeatedly collapse and fill at intervals of centuries to millenia owing to voluminous eruptions. These extensive flows differ greatly in form from pillow lavas found previously along shallower segments of the rift zones; therefore, revision of concepts of volcano stratigraphy and structure may be required.

Holcomb, R.T.; Moore, J.G.; Lipman, P.W.; Belderson, R.H.

1988-05-01

6

Numerous Submarine Radial Vents Revealed on Mauna Loa Volcano  

NASA Astrophysics Data System (ADS)

Among Hawaiian shield volcanoes, Mauna Loa is distinct in having vents outside of its summit and rift zones. These radial vents are located on its northern and western flanks and account for approximately 10% of historic eruptions outside the summit region. Thirty-three subaerial and one submarine vent (active in 1877) were known prior to our work. During a recent Jason2 expedition to the volcano's western flank, nine new submarine radial vents were discovered. Eighty-five samples were collected from these and the 1877 radial vent. Bathymetry and side-scan imagery were acquired using an EM300 multibeam echo sounder. The high resolution data (vertical resolution of approximately 4 m and horizontal resolution of 25 m) allowed us to create the first detailed geologic map of Mauna Loa's western submarine flank. The map was compiled using video and still photography from the Jason2 ROV and geochemical analysis of the samples. The geochemistry includes microprobe glass and XRF whole rock major and trace element data. Eight of the submarine radial vents sampled erupted tholeiitic lavas that are geochemically similar to historical subaerial eruptions on Mauna Loa. However, in contrast to all previously collected Mauna Loa lavas, two of the young vents erupted alkalic basalts. These lavas may have been derived from Mauna Loa, as they have somewhat higher FeO and TiO2 values at a given MgO content than alkalic lavas from neighboring Hualalai volcano, whose vents are located only on rifts 16 km away. Alkalic lavas are indicative of the postshield stage of volcanism and may signal the impending demise of Mauna Loa volcano.

Wanless, D.; Garcia, M. O.; Rhodes, J. M.; Trusdell, F. A.; Schilling, S.; Weis, D.; Fornari, D.; Vollinger, M.

2003-12-01

7

Earthquakes of Loihi submarine volcano and the Hawaiian hot spot.  

USGS Publications Warehouse

Loihi is an active submarine volcano located 35km S of the island of Hawaii and may eventually grow to be the next and S most island in the Hawaiian chain. The Hawaiian Volcano Observatory recorded two major earthquake swarms located there in 1971-1972 and 1975 which were probably associated with submarine eruptions or intrusions. The swarms were located very close to Loihi's bathymetric summit, except for earthquakes during the second stage of the 1971-1972 swarm, which occurred well onto Loihi's SW flank. The flank earthquakes appear to have been triggered by the preceding activity and possible rifting along Loihi's long axis, similar to the rift-flank relationship at Kilauea volcano. Other changes accompanied the shift in locations from Loihi's summit to its flank, including a shift from burst to continuous seismicity, a rise in maximum magnitude, a change from small earthquake clusters to a larger elongated zone, a drop in b value, and a presumed shift from concentrated volcanic stresses to a more diffuse tectonic stress on Loihi's flank. - Author

Klein, F. W.

1982-01-01

8

Debris Avalanche Formation at Kick'em Jenny Submarine Volcano  

Microsoft Academic Search

Kick'em Jenny submarine volcano near Grenada is the most active volcanic center in the Lesser Antilles arc. Multibeam surveys of the volcano by NOAA in 2002 revealed an arcuate fault scarp east of the active cone, suggesting flank collapse. More extensive NOAA surveys in 2003 demonstrated the presence of an associated debris avalanche deposit, judging from their surface morphologic expression

H. Sigurdsson; S. N. Carey; D. Wilson

2005-01-01

9

Integrated volcanologic and petrologic analysis of the 1650 AD eruption of Kolumbo submarine volcano, Greece  

NASA Astrophysics Data System (ADS)

Kolumbo submarine volcano, located 7 km northeast of Santorini, Greece in the Aegean Sea, last erupted in 1650 AD. Submarine and subaerial explosive activity lasted for a period of about four months and led to the formation of thick (~ 250 m) highly stratified pumice deposits on the upper crater walls as well as extensive pumice rafts that were dispersed throughout the southern Aegean Sea. Subaerial tephra fallout from eruption columns that breached the surface occurred as far east as Turkey.

Cantner, Kathleen; Carey, Steven; Nomikou, Paraskevi

2014-01-01

10

Are midwater shrimp trapped in the craters of submarine volcanoes by hydrothermal venting?  

Microsoft Academic Search

The biology of Kick’em Jenny (KEJ) submarine volcano, part of the Lesser Antilles volcanic arc and located off the coast of Grenada in the Caribbean Sea, was studied during a cruise in 2003. Hydrothermal venting and an associated biological assemblage were discovered in the volcanic crater (?250m depth). Warm water with bubbling gas emanated through rock fissures and sediments. Shrimp

Karen F. Wishner; Jason R. Graff; Joel W. Martin; S. Carey; H. Sigurdsson; B. A. Seibel

2005-01-01

11

Submarine sand volcanos: experiments and numerical modelling  

NASA Astrophysics Data System (ADS)

Fluid overpressure at the bottom of a soil layer may generate fracturation in preferential paths for a cohesive material. But the case of sandy soils is rather different: a significant internal flow is allowed within the material and can potentially induce hydro-mechanical instabilities whose most common example is fluidization. Many works have been devoted to fluidization but very few have the issue of initiation and development of a fluidized zone inside a granular bed, prior entire fluidization of the medium. In this contribution, we report experimental results and numerical simulations on a model system of immersed sand volcanos generated by a localized upward spring of liquid, injected at constant flow-rate at the bottom of a granular layer. Such a localized state of fluidization is relevant for some industrial processes (spouted bed, maintenance of navigable waterways,…) and for several geological issues (kimberlite volcano conduits, fluid venting, oil recovery in sandy soil, More precisely, what is presented here is a comparison between experiments, carried out by direct visualization throughout the medium, and numerical simulations, based on DEM modelling of the grains coupled to resolution of NS equations in the liquid phase (LBM). There is a very good agreement between the experimental phenomenology and the simulation results. When the flow-rate is increased, three regimes are successively observed: static bed, fluidized cavity that does not extend to the top of the layer, and finally fluidization over the entire height of layer that creates a fluidized chimney. A very strong hysteretic effect is present here with an extended range of stability for fluidized cavities when flow-rate is decreased back. This can be interpreted in terms force chains and arches. The influences of grain diameter, layer height and injection width are studied and interpreted using a model previously developed by Zoueshtiagh [1]. Finally, growing rate of the fluidized zone and possible coupling between two distinct injection orifices are also discussed.

Philippe, P.; Ngoma, J.; Delenne, J.

2012-12-01

12

Time series analysis of discolored seawater reflectance observed by Advanced Visible and Near Infrared Radiometer type 2 (AVNIR-2) at Fukutoku-Okonaba submarine volcano, Japan  

NASA Astrophysics Data System (ADS)

Monitoring submarine volcanoes is not an easy task compared to land volcanoes because they are covered by seawater and located in remote areas. Satellite remote sensing is a powerful tool for monitoring underwater volcanic activities such as discolored seawater, floating material and volcanic plumes. Discolored seawater is a good indicator of submarine volcanic activities. Advanced Visible and Near Infrared Radiometer type 2 (AVNIR-2) made extensive observations from 2006 to 2011 of the Fukutoku-Okanoba submarine volcano, which is located 1300 km south of Tokyo, and is one of the most active submarine volcanoes in Japan. The high discolored seawater brightness coincides with relatively high activity of Fukutoku-Okanoba. No discolored seawater was observed for 6 months before the 2010 Fukutoku-Okanoba submarine eruption, meaning that Fukutoku-Okanoba was quiescent before the eruption. Both high brightness and apparent color change of discolored seawater derived from AVNIR-2 mean emergence of large amount of hot spring water, implying that the submarine volcano is highly active. This study demonstrates that satellite remote sensing is an effective tool for monitoring activities of inaccessible submarine volcanoes.

Urai, Minoru

2014-01-01

13

Environmental monitoring of El Hierro Island submarine volcano, by combining low and high resolution satellite imagery  

NASA Astrophysics Data System (ADS)

El Hierro Island, located at the Canary Islands Archipelago in the Atlantic coast of North Africa, has been rocked by thousands of tremors and earthquakes since July 2011. Finally, an underwater volcanic eruption started 300 m below sea level on October 10, 2011. Since then, regular multidisciplinary monitoring has been carried out in order to quantify the environmental impacts caused by the submarine eruption. Thanks to this natural tracer release, multisensorial satellite imagery obtained from MODIS and MERIS sensors have been processed to monitor the volcano activity and to provide information on the concentration of biological, chemical and physical marine parameters. Specifically, low resolution satellite estimations of optimal diffuse attenuation coefficient (Kd) and chlorophyll-a (Chl-a) concentration under these abnormal conditions have been assessed. These remote sensing data have played a fundamental role during field campaigns guiding the oceanographic vessel to the appropriate sampling areas. In addition, to analyze El Hierro submarine volcano area, WorldView-2 high resolution satellite spectral bands were atmospherically and deglinted processed prior to obtain a high-resolution optimal diffuse attenuation coefficient model. This novel algorithm was developed using a matchup data set with MERIS and MODIS data, in situ transmittances measurements and a seawater radiative transfer model. Multisensor and multitemporal imagery processed from satellite remote sensing sensors have demonstrated to be a powerful tool for monitoring the submarine volcanic activities, such as discolored seawater, floating material and volcanic plume, having shown the capabilities to improve the understanding of submarine volcanic processes.

Eugenio, F.; Martin, J.; Marcello, J.; Fraile-Nuez, E.

2014-06-01

14

Esmeralda Bank: Geochemistry of an active submarine volcano in the Mariana Island Arc  

Microsoft Academic Search

Esmeralda Bank is the southernmost active volcano in the Izu-Volcano-Mariana Arc. This submarine volcano is one of the most active vents in the western Pacific. It has a total volume of about 27 km3, rising to within 30 m of sea level. Two dredge hauls from Esmeralda recovered fresh, nearly aphyric, vesicular basalts and basaltic andesites and minor basaltic vitrophyre.

Robert J. Stern; L. D. Bibee

1984-01-01

15

South Hachijyo Volcano -Initial Stage of Submarine Saldera Sctivity-  

NASA Astrophysics Data System (ADS)

South Hachijyo Volcano (SHV), a part of Northern Izu-Bonin Arc, is located between Hachijyojima Is. and Aogashima Is. SHV is composed of four blocks (somma) surrounding a bathymetric low. Each block is flat-topped and has a scarp with a gentle slope. The bathymetric low, encircled by the -400m contour line, extends vertically 160m to the top of the SHV. At the bottom of the bathymetric low lies a small depressional structure (caldera floor), which is approximately 2 km in diameter. At the middle of this structure lies a N-S trending central cone that is 1.3*0.9km in diameter and 100m high. We collected many dredge samples of pumice, basaltic fragments, and Q-diorite. Based on observations from a submersible, the sediments on the caldera floor consist of sorted pumice, unsorted pumice and coarse sand. Huge pumice blocks were observed near the slope of the central cone. Angular M-type pumice block and rhyolitic breccias were observed on the top of the central cone. Several rhyolitic volcanic cones (knolls) were observed around the central cone in the caldera floor. Therefore these rhyolitic fragments are associated with dome activities. The result of total geomagnetic analysis indicates that non-magnetic layer (about 600-900m thick) exists at the Hachijyo insular shelf (HIS). Non-magnetic layer in SHV covers magnetic basement, and the south part of it is shallower than the north part. Single-channel seismic records indicate that well-stratified layers (with a total thickness of 700m) exist at the HIS. These layers are corresponds to non-magnetic layer, and the thickness of these layers (interpreted as volcanic products from Hachijyojima Is.) decreases from Hachijyojima toward SHV. Therefore, the production of volcanic material from SHV has been small. Some crypt dome structures are observed under each block (somma). The seismic profiles show knolls atop the stratified somma and the caldera floor. From the geological and geophysical data, we interpret the following regarding the evolution of the SHV. Despite the fact that this volcanic structure is young, we observe morphology that suggests the existence of a caldera that is characterized by gentle slopes that are not well stratified. We interpret the relief between the caldera floor and the somma tops as having been caused by crypt dome intrusion that elevates the somma, rather than by depression of caldera floor after huge eruption. This interpretation is supported by the lack of voluminous volcanic product around the somma. In conclusion, we consider SHV to be in an initial stage of submarine caldera volcanism that is characterized by dike (knoll) complex activity without large volcanic eruptions.

Sakamoto, I.; Ishida, M.

2003-12-01

16

Daily Variations of Methane Flux from Submarine Mud Volcanoes in Southwest Taiwan  

NASA Astrophysics Data System (ADS)

Submarine mud volcanoes are features that episodically emit gases, fluids, and mud onto the seafloor. Methane is the representative gas transport by mud volcanoes efficiently from deep buried sediment to the water column, and potentially to the atmosphere as a greenhouse gas. An active mud volcano, site-G96, located at the upper slope of southwest Taiwan, has plume from the top of mud volcano (360 m) direct to the sea surface. We can observe the bubbles at the sea surface. This study was conducted during cruise OR3-1693 in June 2013. To understand the activity of gas emissions of mud volcano, we utilized the 38kz echo sounder to scan back and forth over the site-G96 and obtained 53 acoustic images of plumes. Five water column samples were collected above the venting of G96 at the tidal maximum and minimum. Three gravity cores were taken at the mudflow site of G96. The results show high concentration of methane (38,522ul/l) and shallow depth of sulfate methane transition zone (~70cm) in the cored sediment profiles. The C1/(C2+C3) ratios from cored sediments are in the range of 29-392, indicating that the methane gas is mostly thermogenic in origin. Calculated areas of the plumes from echo sounder images show good correlation with the tide variations during the survey on 1st -2nd June 2013. Flux of methane from the water column to atmosphere can be estimated by diffusive exchange equation, showing that gas emission from an active mud volcano could be largely various (0.065, 3.426, 3.414, 0, 41.739umol m-2 d-1) from time to time, at least, in this study.

Yang, Tsung-Han; Yang, Tsanyao; Chen, Naichen; Lin, Saulwood; Wang, Pei-Ling

2014-05-01

17

Rapid rates of growth and collapse of Monowai submarine volcano in the Kermadec Arc  

NASA Astrophysics Data System (ADS)

Most of Earth's volcanoes are under water. As a result of their relative inaccessibility, little is known of the structure and evolution of submarine volcanoes. Advances in navigation and sonar imaging techniques have made it possible to map submarine volcanoes in detail, and repeat surveys allow the identification of regions where the depth of the sea floor is actively changing. Here we report the results of a bathymetric survey of Monowai submarine volcano in the Tonga-Kermadec Arc, which we mapped twice within 14 days. We found marked differences in bathymetry between the two surveys, including an increase in seafloor depth up to 18.8m and a decrease in depth up to 71.9m. We attribute the depth increase to collapse of the volcano summit region and the decrease to growth of new lava cones and debris flows. Hydroacoustic T-wave data reveal a 5-day-long swarm of seismic events with unusually high amplitude between the surveys, which directly link the depth changes to explosive activity at the volcano. The collapse and growth rates implied by our data are extremely high, compared with measured long-term growth rates of the volcano, demonstrating the pulsating nature of submarine volcanism and highlighting the dynamic nature of the sea floor.

Watts, A. B.; Peirce, C.; Grevemeyer, I.; Paulatto, M.; Stratford, W.; Bassett, D.; Hunter, J. A.; Kalnins, L. M.; de Ronde, C. E. J.

2012-07-01

18

Distribution of tephra from the 1650 AD submarine eruption of Kolumbo volcano, Greece  

NASA Astrophysics Data System (ADS)

Kolumbo submarine volcano, located 7 km northeast of Santorini in the Aegean Sea, last erupted in 1650 AD resulting in about 70 fatalities on Thera from gas discharge and significant coastal destruction from tsunamis. Extensive pumice rafts were reported over a large area surrounding Santorini, extending as far south as Crete. Tephra from the 1650 AD submarine eruption has been correlated in sediment box cores using a combination of mineralogy and major element composition of glass shards. The biotite-bearing rhyolite of Kolumbo can be readily discriminated from other silicic pyroclastics derived from the main Santorini complex. In general the tephra deposits are very fine grained (silt to fine sand-size), medium gray in color, and covered by about 10 cms of brown hemipelagic sediment. This corresponds to an average background sedimentation rate of 29 cm/kyr. The distribution of the 1650 AD Kolumbo tephra extends over an area larger than previously inferred from seismic profiles on the volcano's slopes and in adjacent basins. The cores indicate tephra deposits at least 19 km from the caldera, more than double the approximate 9 km inferred from seismic data. The preferential occurrence of the tephra within basins and sedimentological features such as cross bedding and laminations suggests that emplacement was dominated by sediment gravity flows generated from submarine and subaerial eruption plumes. We suggest that generation of the sediment gravity flows took place by collapse of submarine eruption columns and by Rayleigh-Taylor instabilities that formed on the sea surface as subaerial fallout accumulated from parts of the columns that breached the surface. Additionally, SEM imaging reveals particle morphologies that can be attributed to fragmentation by both primary volatile degassing (bubble wall shards) and phreatomagmatic activity (blocky equant grains). It is likely that phreatomagmatic activity became more important in the latter stages of the eruptive sequence when eruptions columns broke the surface and a small ephemeral island was formed. The fine grain marine tephra deposits surrounding Kolumbo represent the compliment to the very fines-poor proximal pumice sequence exposed in the crater walls and demonstrates the very effective fractionation of fine tephra that can take place during explosive submarine eruptions.

Fuller, S. A.; Carey, S.; Nomikou, P.

2013-12-01

19

Degassing history of water, sulfur, and carbon in submarine lavas from Kilauea Volcano, Hawaii  

Microsoft Academic Search

Major, minor, and dissolved volatile element concentrations were measured in tholeiitic glasses from the submarine portion (Puna Ridge) of the east rift zone of Kilauea Volcano, Hawaii. Dissolved HâO and S concentrations display a wide range relative to nonvolatile incompatible elements at all depths. This range cannot be readily explained by fractional crystallization, degassing of HâO and S during eruption

Jacqueline Eaby Dixon; E. M. Stolper; D. A. Clague

1991-01-01

20

New Perspectives on the Structure and Morphology of the Submarine Flanks of Galápagos Volcanoes- Fernandina and Isabela  

NASA Astrophysics Data System (ADS)

The submarine flanks of oceanic volcanoes are dynamic environments that reflect the history of volcanic construction and mass-wasting. The submarine slopes of the Galápagos had only been investigated during two modern research cruises - the 1990 PLUME 2 cruise and during the 2000 AHA-Nemo cruise. These data provide the backdrop for a recent sonar mapping and dredging cruise, carried out in Aug-Sept., 2001 on board R/V Revelle, over the southwestern and western edge of the Galápagos platform. The survey included detailed MR1 side-scan sonar imagery (gridded at 8 m pixel resolution) and EM120 multibeam bathymetry (gridded at 100 m pixel resolution), which provided the basis for detailed dredging and towed camera investigations of the submarine flanks of Fernandina and Isabela. The principal geologic provinces delineated by the MR1 sonar imagery include submarine rift zones, major landslides between the rifts, and inferred young lava flows at 3000-3500 m depth located 10-20 km west of the islands. Prominent submarine terraces extend for tens of kilometers along the platform edge south of Isabela and west of Floreana, and in the bight between Fernandina and Cerro Azul volcanoes. The depth range for the terraces is variable between 2000-3300 m. Galápagos submarine rift zones are characterized by mottled backscatter reflectivity seen elsewhere on seamounts, Hawaiian submarine rifts, and the mid-ocean ridge, and are interpreted as constructional submarine volcanic terrain comprising pillow and lobate lava. Extensive spatial variability in acoustic contrast is visible in the MR1 sonar data and is interpreted as complex inter-fingering of submarine eruptive units. These areas of presumably young, high reflectivity flows are located away from the submarine rifts and appear to overlie sediment. These flows cover distances as great as ~10-15 km and are located 10-20 km from the nearest coastline. These large submarine flows may relate to large subaerial events such as the 1968 Fernandina caldera collapse which was unaccompanied by subaerial eruptions. Four prominent terraces characterize the slope south of Isabela and west of Floreana, covering an area of ~600 km2 between ~1500-3000 m, and roughly occur at ~400m depth intervals (2200m, 2500m, 2900m and 3300m). Landslides and sculpting of the platform edge by mass-wasting are imaged in the sidescan sonar data as down slope streaming of light/dark acoustic patterns. This contrasts with the western edge of the platform, north of Isabela and west of Fernandina, that is dominated by submarine rift zones and is interpreted as younger volcanic terrain. The complexity of the morphology and variability of constructional and erosional terrains along the western margin of the platform are clear indicators of the more youthful terrain immediately north and west of Fernandina, the leading edge of the Galápagos hotspot.

Fornari, D. J.; Kurz, M. D.; Geist, D. J.; Johnson, P. D.; Peckman, U. G.; Scheirer, D.

2001-12-01

21

Argon-40: Excess in submarine pillow basalts from Kilauea Volcano, Hawaii  

USGS Publications Warehouse

Submarine pillow basalts from Kilauea Volcano contain excess radiogenic argon-40 and give anomalously high potassium-argon ages. Glassy rims of pillows show a systematic increase in radiogenic argon-40 with depth, and a pillow from a depth of 2590 meters shows a decrease in radiogenic argon-40 inward from the pillow rim. The data indicate that the amount of excess radiogenic argon-40 is a direct function of both hydrostatic pressure and rate of cooling, and that many submarine basalts are not suitable for potassium-argon dating.

Brent, Dalrymple, G.; Moore, J. G.

1968-01-01

22

The INGV's new OBS/H: Analysis of the signals recorded at the Marsili submarine volcano  

NASA Astrophysics Data System (ADS)

The ocean bottom seismometer with hydrophone deployed on the flat top of the Marsili submarine volcano (790 m deep) by the Gibilmanna OBS Lab (CNT-INGV) from 12th to 21st July, 2006, recorded more than 1000 transient seismic signals. Nineteen of these signals were associated with tectonic earthquakes: 1 teleseismic, 8 regional (located by INGV) and 10 small local seismic events (non located earthquakes). The regional events were used to determine sensor orientation. By comparing the signals recorded with typical volcanic seismic activity, we were able to group all the other signals into three categories: 817 volcano-tectonic type B (VT-B) events, 159 occurrences of high frequency tremor (HFT) and 32 short duration events (SDE). Small-magnitude VT-B swarms, having a frequency band of 2-6 Hz and a mean length of about 30 s, were almost all recorded during the first 7 days. During the last 2 days, the OBS/H mainly recorded HFT events with frequencies of over 40 Hz and of a few minutes in length. Signals that have similar features in frequency and time domain are generally associated with hydrothermal activity. During the last two days a signal was recorded that had a frequency content similar to that of VT-B events was recorded. It will be referred to as continuous volcanic tremor (CVT). The SDE signals, characterized by a quasi-monochromatic waveform and having an exponential decaying envelope, may have been generated by oscillations of resonant bodies excited by magmatic or hydrothermal activity. By applying polarization and parametric spectral analyses, we inferred that the VT-B were probably multi P-phase events having shallow sources that were situated in narrow azimuthal windows in relation to the positions of the OBS/H. The parametric spectral analysis of the SDE signals allowed us to determine their dominant complex frequencies with high accuracy; these frequencies are distributed in two distinct clusters on the complex plane.

D'Alessandro, Antonino; D'Anna, Giuseppe; Luzio, Dario; Mangano, Giorgio

2009-05-01

23

Rapid mass wasting following nearshore submarine volcanism on Kilauea volcano, Hawaii  

Microsoft Academic Search

The rapid mass wasting of shallow submarine basalts was documented during SCUBA dives along the flanks of Kilauea volcano, Hawaii during the Kii lava entry of the current eruption (19°20.5'N, 154°59.8'W). Lava entered the ocean at this site from mid-February to late March 1990, with several pauses. Dives on 19 20 March 1990 confirmed the widespread formation of lava pillows

Francis J. Sansone; John R. Smith

2006-01-01

24

Long-term explosion records from two erupting submarine volcanoes in the Mariana and Tonga island-arcs  

NASA Astrophysics Data System (ADS)

Records of explosive activity longer than a few weeks are rare for subaerial volcanoes, and nonexistent for submarine volcanoes. From February 2008 to February 2009, we recorded a year long, continuous acoustic and volcanic plume record from NW Rota-1, an erupting submarine volcano located within the Mariana Arc. From December 2008 to May 2009, we also obtained acoustic records of ongoing explosion and tremor activity at West Mata, a submarine volcano in the NE Lau basin near the Tofua volcanic-arc. At NW Rota-1, a hydrophone and turbidity/temperature sensor were moored ~150 m from the volcano’s summit vent (520 m deep). The volcano exhibited frequent degassing explosions lasting 60-120 s, separated by quiet periods of 10-30 s, for the entire 12-months resulting in >284,000 discrete explosion events. The explosions are broadband (1-80 Hz) with typical source levels of 191 dB re ?Pa @ 1m. Harmonic tremor is also present at times in the explosions, typically with <5 Hz fundamentals and extremely high-amplitude overtone peaks near 30 Hz. The fundamentals are likely due to resonance of the entire volcanic edifice, while the peak overtone may represent reverberation of an internal structure, possibly the conduit feeding the summit vent. The hydrophone also documents a 103 decrease in explosion amplitude over the year, marked by a sharp reduction after 6 mos, which may be part of the typical eruption cycle or due to burial of the vent by accumulated ejecta. Explosions at the summit vent produced a steady series of volcanic plumes that carried ash and hydrothermal precipitates into the water column. Hundreds of short-lived turbidity spikes are present, with no long periods of quiescence, indicating changes in explosion intensity did not affect the pattern of volcanic plume creation. Our data are the first to confirm the frequent creation and dispersal of submarine volcanic plumes on a year-long scale. In December 2008 a moored hydrophone (250 Hz) was deployed ~30 km from West Mata, a near-arc boninite volcano discovered actively erupting the month before. An ROV cruise in May 2009 deployed two short-term, high-frequency (1024 Hz) hydrophones within 50 m of the Hades volcanic vent (1208 m deep). Both the long-term and in situ hydrophones detected explosive activity as well as both mono- and polychromatic volcanic tremor throughout their records. ROV video shows the acoustic signals are from violent degassing bursts from within lava extruding at the Hades vent (summit of West Mata). The explosions exhibit both short (10s of sec) and long (2-10 min) duration modes of cyclic activity. Many explosion signals also show harmonic tremor within their codas indicative of resonance from within the volcanic edifice. Frequently the explosion records are overlapped by monochromatic tremor from a narrow band within a range from 20-100 Hz. The source of this resonance is not yet clear (although not man-made) and is possibly from a nearby, unseen vent or magma movement within the volcanic edifice.

Dziak, R. P.; Embley, R. W.; Baker, E. T.; Chadwick, W. W.; Resing, J.; Matsumoto, H.; Walker, S. L.; Bohnenstiehl, D. R.; Klink, H.

2009-12-01

25

The Geologic Setting of Hydrothermal Vents at Mariana Arc Submarine Volcanoes: High-Resolution Bathymetry and ROV Observations  

NASA Astrophysics Data System (ADS)

Remotely operated vehicle (ROV) dives were made at 7 submarine volcanoes between 14-23° N in the Mariana Arc in April 2004 with the ROPOS ROV. Six of these volcanoes were known to be hydrothermally active from CTD data collected during a previous expedition in March 2003: NW Rota-1, E Diamante, NW Eifuku, Daikoku, Kasuga-2, and Maug, a partly submerged caldera. The physical setting of hydrothermal venting varies widely from volcano to volcano. High-resolution bathymetric surveys of the summits of NW Rota-1 and NW Eifuku volcanoes were conducted with an Imagenex scanning sonar mounted on ROPOS. Near bottom observations during ROPOS dives were recorded with digital video and a digital still camera and the dives were navigated acoustically from the R/V Thompson using an ultra-short baseline system. The mapping and dive observations reveal the following: (1) The summits of some volcanoes have pervasive diffuse venting (NW Rota-1, Daikoku, NW Eifuku) suggesting that hydrothermal fluids are able to circulate freely within a permeable edifice. At other volcanoes, the hydrothermal venting is more localized (Kasuga-2, Maug, E Diamante), suggesting more restricted permeability pathways. (2) Some volcanoes have both focused venting at depth and diffuse venting near the summit (E Diamante, NW Eifuku). Where the hydrothermal vents are focused, fluid flow appears to be localized by massive lava outcrops that form steep cliffs and ridges, or by subsurface structures such as dikes. High-temperature (240° C) venting was only observed at E Diamante volcano, where the "Black Forest" vent field is located on the side of a constructional cone near the middle of E Diamante caldera at a depth of 350 m. On the side of an adjacent shallower cone, the venting style changed to diffuse discharge and it extended all the way up into the photic zone (167 m). At NW Eifuku, the pattern of both deep-focused and shallow-diffuse venting is repeated. "Champagne vent" is located at 1607 m, ~150 m below the summit, and is characterized by focused flow of CO2-rich fluids, whereas the summit has extensive areas of diffuse venting and is covered with thick bacterial mats. (3) Some of the most remarkable vent sites are deep, narrow volcanic craters at NW Rota-1 and Daikoku volcanoes. The crater at NW Rota-1 volcano (named "Brimstone Pit") is 15-m wide, 20-m deep, funnel shaped, and was actively erupting ash, lapilli, and molten sulfur. The rim of Brimstone Pit is composed of welded spatter and is located at 550 m depth, about 30 m below the summit. Other diffuse hydrothermal sites at NW Rota-1 are located along the rocky summit ridge. At Daikoku volcano, an extraordinary crater emitting cloudy hydrothermal fluid was found at 375 m depth on the north shoulder of the volcano, about 75 m below the summit. This crater was at least 135 m deep and had a remarkably cylindrical cross-section with a diameter of ~50 m. ROPOS descended 75 m into the crater and was still at least 60 m above the bottom, according to the altimeter, when we were forced to cease operations due to weather. In addition, diffuse hydrothermal fluids seep from large areas of the summit and upper slopes of Daikoku.

Chadwick, W. W.; Embley, R. W.; de Ronde, C. E.; Stern, R. J.; Hein, J.; Merle, S.; Ristau, S.

2004-12-01

26

Tremor Source Location at Okmok Volcano  

NASA Astrophysics Data System (ADS)

Initial results using an amplitude-based tremor location program have located several active tremor episodes under Cone A, a vent within Okmok volcano's 10 km caldera. Okmok is an andesite volcano occupying the north-eastern half of Umnak Island, in the Aleutian islands. Okmok is defined by a ~2000 y.b.p. caldera that contains multiple cinder cones. Cone A, the youngest of these, extruded lava in 1997 covering the caldera floor. Since April 2003, continuous seismic data have been recorded from eight vertical short-period stations (L4-C's) installed at distances from Cone A ranging from 2 km to 31 km. In 2004 four additional 3- component broadband stations were added, co-located with continuous GPS stations. InSAR and GPS measurements of post-eruption deformation show that Okmok experienced several periods of rapid inflation (Mann and Freymueller, 2002), from the center of the 10 km diameter caldera. While there are few locatable VT earthquakes, there has been nearly continuous low-level tremor with stronger amplitude bursts occurring at variable rates and durations. The character of occurrence remained relatively constant over the course of days to weeks until the signal ceased in mid 2005. Within any day, tremor behavior remains fairly consistent, with bursts closely resembling each other, suggesting a single main process or source location. The tremor is composed of irregular waves with a broad range of frequencies, though most energy resides between ~2 Hz and 6 Hz. Attempts to locate the tremor using traditional arrival time methods fail because the signal is emergent, with envelopes too ragged to correlate on time scales that hold much hope for a location. Instead, focus was shifted to the amplitude ratios at various stations. Candidates for the tremor source include the center of inflation and Cone A, 3 km to the south-west. For all dates on record, data were band pass filtered between 1 and 5 Hz, then evaluated in 20.48 second windows (N=2048, sampling rate=100 Hz), at 20 second intervals. Root-mean- square (rms) values were then calculated for each window of data. The ratios of these RMS amplitudes were used to investigate the tremor behavior. The ratio changes between tremor and non-tremor events suggest that the sources for episodes were closer to Cone A (and station OKCF) than they were to other locales in the caldera. Methods from Battaglia's PhD thesis (2001) were used as guidelines for a tremor location program based on amplitude decay. Written in MATLAB®, this program can be run in near-real time to estimate the tremor source location and strength. Further refinement is underway, as is an examination of all other days that have suitable data .

Reyes, C. G.; McNutt, S. R.

2007-12-01

27

The acoustic response of submarine volcanoes in the Tofua Arc and northern Lau Basin following two great earthquakes in Samoa and Chile  

NASA Astrophysics Data System (ADS)

Using a correlation-based detector operating on data from a short-baseline hydrophone array, persistent volcano-acoustic sources are identified within the ambient noise field of the Lau Basin during the period between January 2009 and April 2010. The submarine volcano West Mata and adjacent volcanic terrains, including the northern Matas and Volcano O, are the most active acoustic sources during the 15-month period of observation. Other areas of long-term activity include the Niua hydrothermal field, the volcanic islands of Hunga-Ha'apai, Founalei, Niuatoputapu and Niuafo'ou, two unnamed seamounts located along the southern Tofua Arc, and at least three unknown sites within the northern Lau Basin. Following the great Samoan earthquake on 29 September of 2009, seven of the volcano-acoustic sources identified exhibit increases in the rate of acoustic detection. These changes persist over time scales of days-to-months and are observed up to 900 km from the earthquake hypocenter. At least one of the volcano-acoustic sources that did not respond to the 2009 Samoan earthquake exhibits an increase in detection rate following the great Mw 8.8 Chile earthquake that occurred at a distance of ~9,500 km on 27 February 2010. These observations suggest that great earthquakes may have undocumented impacts on Earth's vast submarine volcanic systems, potentially increasing the short-term flux of magma and volcanic gas into the overlying ocean.

Bohnenstiehl, D. R.; Dziak, R. P.; Matsumoto, H.; Conder, J. A.

2013-12-01

28

Degassing history of water, sulfur, and carbon in submarine lavas from Kilauea Volcano, Hawaii  

SciTech Connect

Major, minor, and dissolved volatile element concentrations were measured in tholeiitic glasses from the submarine portion (Puna Ridge) of the east rift zone of Kilauea Volcano, Hawaii. Dissolved H{sub 2}O and S concentrations display a wide range relative to nonvolatile incompatible elements at all depths. This range cannot be readily explained by fractional crystallization, degassing of H{sub 2}O and S during eruption on the seafloor, or source region heterogeneities. Dissolved CO{sub 2} concentrations, in contrast, show a positive correlation with eruption depth and typically agree within error with the solubility at that depth. The authors propose that most magmas along the Puna Ridge result from (1) mixing of a relatively volatile-rich, undegassed component with magmas that experienced low pressure (perhaps subaerial) degassing during which substantial H{sub 2}O, S, and CO{sub 2} were lost, followed by (2) fractional crystallization of olivine, clinopyroxene, and plagioclase from this mixture to generate a residual liquid; and (3) further degassing, principally of CO{sub 2} for samples erupted deeper than 1,000 m, during eruption on the seafloor. They predict that average Kilauean primary magmas with 16% MgO contain {approximately}0.47 wt % H{sub 2}0, {approximately}900 ppm S, and have {delta}D values of {approximately}{minus}30 to {minus}40%. The model predicts that submarine lavas from wholly submarine volcanoes (i.e., Loihi), for which there is no opportunity to generate the degassed end member by low pressure degassing, will be enriched in volatiles relative to those from volcanoes whose summits have breached the sea surface (i.e., Kilauea and Mauna Loa).

Dixon, J.E.; Stolper, E.M. (California Institute of Technology, Pasadena (USA)); Clague, D.A. (Geological Survey, Menlo Park, CA (USA))

1991-05-01

29

Collapse and reconstruction of Monowai submarine volcano, Kermadec arc, 1998-2004  

NASA Astrophysics Data System (ADS)

Monowai submarine volcano is one of the three most historically active volcanoes of the Kermadec arc. Repeat multibeam surveys of Monowai Cone from September 1998 and September 2004 and T wave data recorded by the Réseau Sismique Polynésien network for the same period document the collapse and subsequent regrowth of the cone within this 6-a period. Grid differencing of the two bathymetric data sets, acquired 6 a apart, reveals that a landslide ˜2230 m long occurred between the surveys, within which a postcollapse cone and talus ridge (˜0.023 km3 in volume) subsequently formed. The volume of this collapse, minus postcollapse construction, is ˜0.085 km3. We interpret an unusual, strong-amplitude T wave event on 24 May 2002 as recording "hot landsliding", where the 100- to 160-m-thick collapse has "unroofed" the uppermost parts of the vent conduit, with the subsequent explosive interaction, and cooling, of hot magma and volcaniclastic rubble with ambient seawater. This interpretation is consistent with the lack of emergent events, sharp onset, and large amplitude of the 24 May 2002 T waves. The subsequent >2500 T wave events, between November 2002 and September 2004, occurred in swarms with emerging and waning activity and with typical explosive volcanic acoustic signatures, which are interpreted as recording the regrowth of an ˜90-m-high cone back to a near-1998 elevation, at an average rate of 47 m a-1. This study provides (1) a lower bound for frequency-magnitude relationships of landsliding for submarine arc volcanoes and (2) estimates of 0.013 km3 a-1 of submarine cone growth during eruptive cycles.

Wright, Ian C.; Chadwick, William W.; de Ronde, Cornel E. J.; Reymond, Dominique; Hyvernaud, Olivier; Gennerich, Hans-Hermann; Stoffers, Peter; Mackay, Kevin; Dunkin, Miles A.; Bannister, Stephen C.

2008-08-01

30

Submarine landslides and volcanic features on Kohala and Mauna Kea volcanoes and the Hana Ridge, Hawaii  

NASA Astrophysics Data System (ADS)

The deep submarine eastern flanks of Mauna Kea, Kohala, and Haleakala volcanoes were mapped for the first time with a multibeam bathymetric and sidescan sonar system during joint Japan-US cruises aboard the JAMSTEC vessel R/V Yokosuka in 1999. The Pololu slump off northeast Kohala is overlain by a carbonate platform in the shallow region and the deeper areas are incised by downslope oriented channels. It is cut by several faults and slump scars and appears to override an older slide located farther east, here named the Laupahoehoe slump. The structures characteristic of the Laupahoehoe slump are NW-SE oriented scarp-and-bench topographic features analogous to the Hilina slump on the mobile SE flank of Kilauea. Enclosed basins lie at 3000-5000 m, fronted by ridges on their seaward sides. The basins may result from local rotational slumps or from uplift above discontinuous thrust faults. The Laupahoehoe slump appears to be overlapped by shield margins of both Kohala and Mauna Kea and thus may have been derived from an elongate Kohala edifice. A large debris apron continues from the base of the two-slide complex, abutting the distal Hana Ridge (Haleakala east rift zone). The tip of the Hana Ridge displays a curious steep-sided arcuate rift tip that resembles the classic amphitheater scarp of a landslide. Numerous flat-topped volcanic domes are distributed along the broad crest of the lower rift zone. Similar cones, though fewer in number, are also present on the Hilo Ridge, which may be the continuation of a Kohala rift zone.

Smith, John R.; Satake, Kenji; Morgan, Julia K.; Lipman, Peter W.

31

Helium Isotopes of Fluids from Submarine Volcanoes in the South-Okinawa Trough  

NASA Astrophysics Data System (ADS)

Many active submarine volcanoes have been found in southern Okinawa Trough. Water column samples from the hydrothermal plumes above venting volcanoes were collected during the OR2-1897 and -1984 cruises. Meanwhile, diving at shallower depths were conducted several times to collect the water samples near the venting sites. In total, 122 water samples from various depths in the offshore area of NE Taiwan were collected for dissolved gases and helium isotopes measurement. The dissolved gases of water column samples show that the CO2 concentration and the alkalinity increase with depth and become higher at the bottom, while the result of O2 concentration shows a reverse pattern. The 3He/4He ratios near the vicinity of active Kueishantao volcano show highest value, up to 5.5 RA, where RA is the atmospheric ratios of 1.39 x 10-6. The plot of 3He/4He and 3He/20Ne ratios suggests that there may be different sources in this region. Furthermore, we will estimate the helium flux from the venting volcanoes in this area.

Hsin Kao, Li; Yang, Tsanyao Frank; Wen, Hsin-Yi; Chen, Ai-Ti; Lee, Hsiao-Fen

2014-05-01

32

Eruption-fed particle plumes and volcaniclastic deposits at a submarine volcano: NW Rota1, Mariana Arc  

Microsoft Academic Search

NW Rota-1 is an active submarine volcano in the Mariana Arc with a summit depth of 517 m and an explosively erupting volcanic vent southwest of the summit at a depth of 530–560 m. During a period of ongoing explosive eruptions, particle plumes surrounded the volcano and at least 3.3 × 107 m3 of volcaniclastic material was deposited on the

Sharon L. Walker; Edward T. Baker; Joseph A. Resing; William W. Chadwick; Geoffrey T. Lebon; John E. Lupton; Susan G. Merle

2008-01-01

33

Submarine geology of the Hilina slump and morpho-structural evolution of Kilauea volcano, Hawaii  

NASA Astrophysics Data System (ADS)

Marine geophysical data, including SEA BEAM bathymetry, HAWAII MR1 sidescan, and seismic reflection profiles, along with recent robot submersible observations and samples, were acquired over the offshore continuation of the mobile Kilauea volcano south flank. This slope comprises the three active hot spot volcanoes Mauna Loa, Kilauea, and Loihi seamount and is the locus of the Hawaiian hot spot. The south flank is the site of frequent low-intensity seismicity as well as episodic large-magnitude earthquakes. Its sub-aerial portion creeps seaward at a rate of approximately 10 cm/year. The Hilina slump is the only large submarine landslide in the Hawaiian Archipelago thought to be active, and this study is one of the first to more highly resolve submarine slide features there. The slump is classified into four distinct zones from nearshore to the island's base. Estimates of size based on these data indicate a slumped area of 2100 km 2 and a volume of 10,000-12,000 km 3, equivalent to about 10% of the entire island edifice. The overall picture gained from these data sets is one of mass wasting of the neovolcanic terrain as it builds upward and seaward, though reinforcement by young and pre-Hawaii seamounts adjacent to the pedestal is apparent. Extensive lava delta deposits are formed by hyaloclastites and detritus from recent lava flows into the sea. These deposits dominate the upper submarine slope offshore of Kilauea, with pillow breccia revealed at mid-depths. Along the lower flanks, massive outcrops of volcanically derived sedimentary rocks were found underlying Kilauea, thus necessitating a rethinking of previous models of volcanic island development. The morphologic and structural evolutionary model for Kilauea volcano and the Hilina slump proposed here attempts to incorporate this revelation. A hazard assessment for the Hilina slump is presented where it is suggested that displacement of the south flank to date has been restrained by a still developing northeast lateral submarine boundary. When it does fully mature, the south flank may be more subject to land slips triggered by large, long duration earthquakes and thus Kilauea may undergo more frequent episodes of failure with increased displacements.

Smith, John R.; Malahoff, Alexander; Shor, Alexander N.

1999-12-01

34

Cyclic eruptions and sector collapses at Monowai submarine volcano, Kermadec arc: 1998-2007  

NASA Astrophysics Data System (ADS)

Repeated multibeam bathymetric surveys at Monowai Cone, a shallow submarine basaltic volcano and part of the Monowai Volcanic Center in the northern Kermadec arc, were conducted in 1998, 2004, and 2007. These surveys document dramatic depth changes at the volcano including negative changes up to -176 m from two sector collapses and positive changes up to +138 m from volcanic reconstruction near the summit and debris avalanche deposits downslope of the slide scars. One sector collapse occurred on the SE slope between 1998 and 2004 with a volume of ˜0.09 km3, and another occurred on the SW slope between 2004 and 2007 with a volume of ˜0.04 km3. The volume of positive depth change due to addition of volcanic material by eruption is of the same order: ˜0.05 km3 between 1998 and 2004 and ˜0.06 km3 between 2004 and 2007. During these time intervals, monitoring by the Polynesian Seismic Network detected frequent T wave swarms at Monowai, indicative of explosive eruptive activity every few months. An unusual T wave swarm on 24 May 2002 was previously interpreted as the collapse event between the 1998 and 2004 surveys, but no similarly anomalous T waves were detected between 2004 and 2007, probably because the Polynesian Seismic Network stations were acoustically shadowed from the second slide event. We interpret that the sector collapses on Monowai are caused by the unstable loading of fragmental erupted material on the summit and steep upper slopes of the volcano (>20°). Moreover, there appears to be a cyclic pattern in which recurrent eruptions oversteepen the cone and periodically lead to collapse events that transport volcaniclastic material downslope to the lower apron of the volcano. Volumetric rate calculations suggest that these two processes may be more or less in equilibrium. The repeated collapses at Monowai are relatively modest in volume (involving only 0.1-0.5% of the edifice volume), have occurred much more frequently than is estimated for larger debris avalanches at subaerial volcanoes, and may be characteristic of how persistently active shallow submarine arc volcanoes grow.

Chadwick, W. W.; Wright, I. C.; Schwarz-Schampera, U.; Hyvernaud, O.; Reymond, D.; de Ronde, C. E. J.

2008-10-01

35

New insights into hydrothermal vent processes in the unique shallow-submarine arc-volcano, Kolumbo (Santorini), Greece  

PubMed Central

We report on integrated geomorphological, mineralogical, geochemical and biological investigations of the hydrothermal vent field located on the floor of the density-stratified acidic (pH ~ 5) crater of the Kolumbo shallow-submarine arc-volcano, near Santorini. Kolumbo features rare geodynamic setting at convergent boundaries, where arc-volcanism and seafloor hydrothermal activity are occurring in thinned continental crust. Special focus is given to unique enrichments of polymetallic spires in Sb and Tl (±Hg, As, Au, Ag, Zn) indicating a new hybrid seafloor analogue of epithermal-to-volcanic-hosted-massive-sulphide deposits. Iron microbial-mat analyses reveal dominating ferrihydrite-type phases, and high-proportion of microbial sequences akin to "Nitrosopumilus maritimus", a mesophilic Thaumarchaeota strain capable of chemoautotrophic growth on hydrothermal ammonia and CO2. Our findings highlight that acidic shallow-submarine hydrothermal vents nourish marine ecosystems in which nitrifying Archaea are important and suggest ferrihydrite-type Fe3+-(hydrated)-oxyhydroxides in associated low-temperature iron mats are formed by anaerobic Fe2+-oxidation, dependent on microbially produced nitrate.

Kilias, Stephanos P.; Nomikou, Paraskevi; Papanikolaou, Dimitrios; Polymenakou, Paraskevi N.; Godelitsas, Athanasios; Argyraki, Ariadne; Carey, Steven; Gamaletsos, Platon; Mertzimekis, Theo J.; Stathopoulou, Eleni; Goettlicher, Joerg; Steininger, Ralph; Betzelou, Konstantina; Livanos, Isidoros; Christakis, Christos; Bell, Katherine Croff; Scoullos, Michael

2013-01-01

36

New insights into hydrothermal vent processes in the unique shallow-submarine arc-volcano, Kolumbo (Santorini), Greece.  

PubMed

We report on integrated geomorphological, mineralogical, geochemical and biological investigations of the hydrothermal vent field located on the floor of the density-stratified acidic (pH ~ 5) crater of the Kolumbo shallow-submarine arc-volcano, near Santorini. Kolumbo features rare geodynamic setting at convergent boundaries, where arc-volcanism and seafloor hydrothermal activity are occurring in thinned continental crust. Special focus is given to unique enrichments of polymetallic spires in Sb and Tl (±Hg, As, Au, Ag, Zn) indicating a new hybrid seafloor analogue of epithermal-to-volcanic-hosted-massive-sulphide deposits. Iron microbial-mat analyses reveal dominating ferrihydrite-type phases, and high-proportion of microbial sequences akin to "Nitrosopumilus maritimus", a mesophilic Thaumarchaeota strain capable of chemoautotrophic growth on hydrothermal ammonia and CO2. Our findings highlight that acidic shallow-submarine hydrothermal vents nourish marine ecosystems in which nitrifying Archaea are important and suggest ferrihydrite-type Fe(3+)-(hydrated)-oxyhydroxides in associated low-temperature iron mats are formed by anaerobic Fe(2+)-oxidation, dependent on microbially produced nitrate. PMID:23939372

Kilias, Stephanos P; Nomikou, Paraskevi; Papanikolaou, Dimitrios; Polymenakou, Paraskevi N; Godelitsas, Athanasios; Argyraki, Ariadne; Carey, Steven; Gamaletsos, Platon; Mertzimekis, Theo J; Stathopoulou, Eleni; Goettlicher, Joerg; Steininger, Ralph; Betzelou, Konstantina; Livanos, Isidoros; Christakis, Christos; Bell, Katherine Croff; Scoullos, Michael

2013-01-01

37

Rapid mass wasting following nearshore submarine volcanism on Kilauea volcano, Hawaii  

NASA Astrophysics Data System (ADS)

The rapid mass wasting of shallow submarine basalts was documented during SCUBA dives along the flanks of Kilauea volcano, Hawaii during the Kii lava entry of the current eruption (19°20.5'N, 154°59.8'W). Lava entered the ocean at this site from mid-February to late March 1990, with several pauses. Dives on 19-20 March 1990 confirmed the widespread formation of lava pillows at this site over a water depth range of 20-40 m, and visual observations suggested that the resulting volcanic deposits were generally stable, despite the steep (˜40°) incline of the seafloor. (The pre-eruptive nearshore seafloor slope was ˜14°.) However, dives on 2 April 1990 revealed that nearly all submarine volcanic features had been subject to mass wasting, as the offshore area had been transformed into a debris field composed of material ranging in size from fine sand to boulder fragments. This generally featureless seascape extended uniformly to beyond the visual range of divers (˜60 m water depth). High-resolution multibeam bathymetry and sidescan imaging indicate that steeply sloped coarse sediment extends down the flanks of Kilauea in this area to abyssal depths, implying a linkage between nearshore submarine volcanism and deep-water deposits.

Sansone, Francis J.; Smith, John R.

2006-03-01

38

Volcanoes  

ERIC Educational Resources Information Center

Describes the forces responsible for the eruptions of volcanoes and gives the physical and chemical parameters governing the type of eruption. Explains the structure of the earth in relation to volcanoes and explains the location of volcanic regions. (GS)

Kunar, L. N. S.

1975-01-01

39

Plume indications from hydrothermal activity on Kawio Barat Submarine Volcano, Sangihe Talaud Sea, North Sulawesi, Indonesia  

NASA Astrophysics Data System (ADS)

Kawio Barat submarine volcano has formed in response to the active tectonic conditions in Sangihe Talaud, an area that lies in the subduction zone between the Molucca Sea Plate and Celebes Sea Plate. Submarine volcanic activity in the western Sangihe volcanic arc is controlled by the west-dipping Molucca Sea Plate as it subducts beneath the Sangihe Arc. A secondary faulting system on Kawio Barat is in a northwest - southeast direction, and creates a network of deep cracks that facilitate hydrothermal discharge in this area. Hydrothermal activity on Kawio Barat was first discovered by joint Indonesia/Australian cruises in 2003. In 2010, as part of the joint US/Indonesian INDEX-SATAL expedition, we conducted CTD casts that confirmed continuing activity. Hydrothermal plumes were detected by light -scattering (LSS) and oxidation-reduction potential (ORP) sensors on the CTD package. LSS anomalies were found between 1600-1900 m, with delta NTU levels of 0.020-0.040. ORP anomalies coincident with the LSS anomalies indicate strong concentrations of reduced species such as H2S and Fe, confirming the hydrothermal origin of the plumes. Images of hydrothermal vents on Kawio Barat Submarine volcano, recorded by high- definition underwater cameras on the ROV “Little Hercules” operated from the NOAA ship Okeanos Explorer, confirmed the presence and sources of the detected vent plumes in the northern and southwest part of the summit in 1800-1900 m depth. In southwest part of this summit chimney, drips of molten sulfur were observed in the proximity of microbal staining.

Makarim, S.; Baker, E. T.; Walker, S. L.; Wirasantosa, S.; Permana, H.; Sulistiyo, B.; Shank, T. M.; Holden, J. F.; Butterfield, D.; Ramdhan, M.; Adi, R.; Marzuki, M. I.

2010-12-01

40

North Kona slump: Submarine flank failure during the early(?) tholeiitic shield stage of Hualalai Volcano  

USGS Publications Warehouse

The North Kona slump is an elliptical region, about 20 by 60 km (1000-km2 area), of multiple, geometrically intricate benches and scarps, mostly at water depths of 2000-4500 m, on the west flank of Hualalai Volcano. Two dives up steep scarps in the slump area were made in September 2001, using the ROV Kaiko of the Japan Marine Science and Technology Center (JAMSTEC), as part of a collaborative Japan-USA project to improve understanding of the submarine flanks of Hawaiian volcanoes. Both dives, at water depths of 2700-4000 m, encountered pillow lavas draping the scarp-and-bench slopes. Intact to only slightly broken pillow lobes and cylinders that are downward elongate dominate on the steepest mid-sections of scarps, while more equant and spherical pillow shapes are common near the tops and bases of scarps and locally protrude through cover of muddy sediment on bench flats. Notably absent are subaerially erupted Hualalai lava flows, interbedded hyaloclastite pillow breccia, and/or coastal sandy sediment that might have accumulated downslope from an active coastline. The general structure of the North Kona flank is interpreted as an intricate assemblage of downdropped lenticular blocks, bounded by steeply dipping normal faults. The undisturbed pillow-lava drape indicates that slumping occurred during shield-stage tholeiitic volcanism. All analyzed samples of the pillow-lava drape are tholeiite, similar to published analyses from the submarine northwest rift zone of Hualalai. Relatively low sulfur (330-600 ppm) and water (0.18-0.47 wt.%) contents of glass rinds suggest that the eruptive sources were in shallow water, perhaps 500-1000-m depth. In contrast, saturation pressures calculated from carbon dioxide concentrations (100-190 ppm) indicate deeper equilibration, at or near sample sites at water depths of -3900 to -2800 m. Either vents close to the sample sites erupted mixtures of undegassed and degassed magmas, or volatiles were resorbed from vesicles during flowage downslope after eruption in shallow water. The glass volatile compositions suggest that the tholeiitic lavas that drape the slump blocks were erupted either (1) early during shield-stage tholeiitic volcanism prior to emergence of a large subaerial edifice, or alternatively (2) from submarine radial vents during subaerial shield-building. Because no radial vents have been documented on land or underwater for the unbuttressed flanks of any Hawaii volcano, alternative (1) is favored. In comparison to other well-documented Hawaiian slumps and landslides, North Kona structures suggest a more incipient slump event, with smaller down-slope motions and lateral displacements.

Lipman, P. W.; Coombs, M. L.

2006-01-01

41

Methane discharge into the Black Sea and the global ocean via fluid flow through submarine mud volcanoes  

NASA Astrophysics Data System (ADS)

During the MARGASCH cruise M52/1 in 2001 with RV Meteor we sampled surface sediments from three stations in the crater of the Dvurechenskii mud volcano (DMV, located in the Sorokin Trough of the Black Sea) and one reference station situated 15 km to the northeast of the DMV. We analysed the pore water for sulphide, methane, alkalinity, sulphate, and chloride concentrations and determined the concentrations of particulate organic carbon, carbonate and sulphur in surface sediments. Rates of anaerobic oxidation of methane (AOM) were determined using a radiotracer ( 14CH 4) incubation method. Numerical transport-reaction models were applied to derive the velocity of upward fluid flow through the quiescently dewatering DMV, to calculate rates of AOM in surface sediments, and to determine methane fluxes into the overlying water column. According to the model, AOM consumes 79% of the average methane flux from depth (8.9 · 10 + 6 mol a - 1 ), such that the resulting dissolved methane emission from the volcano into the overlying bottom water can be determined as 1.9 · 10 + 6 mol a - 1 . If it is assumed that all submarine mud volcanoes (SMVs) in the Black Sea are at an activity level like the DMV, the resulting seepage represents less than 0.1% of the total methane flux into this anoxic marginal sea. The new data from the DMV and previously published studies indicate that an average SMV emits about 2.0 · 10 + 6 mol a - 1 into the ocean via quiescent dewatering. The global flux of dissolved methane from SMVs into the ocean is estimated to fall into the order of 10 + 10 mol a - 1 . Additional methane fluxes arise during periods of active mud expulsion and gas bubbling occurring episodically at the DMV and other SMVs.

Wallmann, Klaus; Drews, Manuela; Aloisi, Giovanni; Bohrmann, Gerhard

2006-08-01

42

Direct Observations of Explosive Eruptive Activity at a Submarine Volcano, NW Rota-1, Mariana Arc  

NASA Astrophysics Data System (ADS)

In April 2006, a series of extraordinary observations of a deep-sea volcanic eruption were made at NW Rota-1, located at 14^{circ}36'N in the Mariana arc, western Pacific. This is a conical, basaltic-andesite submarine volcano with a summit depth of 517 m. Explosive eruptive activity at NW Rota-1 was discovered in 2004 and was witnessed again in 2005, but the activity in 2006 was especially vigorous and well documented. During six dives with the remotely operated vehicle Jason II over a period of 7 days, video observations made at close range documented a diverse and increasingly energetic range of volcanic activity that culminated in explosive bursts with flashes of glowing red lava propelled by violently expanding gases. Other notable activity included discreet degassing events, extrusion of sluggish lava flows, explosions that formed dilute density currents and/or expelled rocks and ash tens of meters from the vent, and rapid pressure oscillations apparently caused by the repeated formation and condensation of steam. During the last dive when the highest extrusion rates were observed, quasi-periodic bursts from the vent, each lasting 1-10 minutes, were separated by pauses lasting 10 seconds to a few minutes. Each burst started as a plug of crusted-over lava rose in the vent and was blown apart by expanding gases, producing large lava bombs with distinctly flat, disc-like shapes. A remarkable aspect of these observations was how close Jason II could be to the vent during the eruptions. This was because the pressure of the overlying seawater dampened the energy of the explosions and slowed the velocity of volcanic ejecta. Also, lava degassing could be visualized with great clarity underwater as either clear bubbles (CO2) or opaque yellow clouds (dominated by SO2 and H2S). A portable hydrophone with a 30-hour recording capacity was deployed twice by Jason II at the summit of NW Rota-1 during the 2006 dive series. The hydrophone data extends the visual observations made at the vent and quantifies the temporal pattern and intensity of the eruptive activity. The expedition to NW Rota-1 in 2006 was supported by the NOAA Ocean Exploration Program.

Chadwick, W. W.; Embley, R. W.; de Ronde, C. E.; Deardorff, N.; Matsumoto, H.; Cashman, K. V.; Dziak, R. P.; Merle, S. G.

2006-12-01

43

Bubble Plumes at NW Rota-1 Submarine Volcano, Mariana Arc: Visualization and Analysis of Multibeam Water Column Data  

NASA Astrophysics Data System (ADS)

During a March 2010 expedition to NW Rota-1 submarine volcano in the Mariana arc a new EM122 multibeam sonar system on the R/V Kilo Moana was used to repeatedly image bubble plumes in the water column over the volcano. The EM122 (12 kHz) system collects seafloor bathymetry and backscatter data, as well as acoustic return water column data. Previous expeditions to NW Rota-1 have included seafloor mapping / CTD tow-yo surveys and remotely operated vehicle (ROV) dives in 2004, 2005, 2006 and 2009. Much of the focus has been on the one main eruptive vent, Brimstone, located on the south side of the summit at a depth of ~440m, which has been persistently active during all ROV visits. Extensive degassing of CO2 bubbles have been observed by the ROV during frequent eruptive bursts from the vent. Between expeditions in April 2009 and March 2010 a major eruption and landslide occurred at NW Rota-1. ROV dives in 2010 revealed that after the landslide the eruptive vent had been reorganized from a single site to a line of vents. Brimstone vent was still active, but 4 other new eruptive vents had also emerged in a NW/SE line below the summit extending ~100 m from the westernmost to easternmost vents. During the ROV dives, the eruptive vents were observed to turn on and off from day to day and hour to hour. Throughout the 2010 expedition numerous passes were made over the volcano summit to image the bubble plumes above the eruptive vents in the water column, in order to capture the variability of the plumes over time and to relate them to the eruptive output of the volcano. The mid-water sonar data set totals >95 hours of observations over a 12-day period. Generally, the ship drove repeatedly over the eruptive vents at a range of ship speeds (0.5-4 knots) and headings. In addition, some mid-water data was collected during three ROV dives when the ship was stationary over the vents. We used the FMMidwater software program (part of QPS Fledermaus) to visualize and analyze the data collected with this new mid-water technology. The data show that during some passes over the vent all 5 eruptive vents were contributing to the plume above the volcano, whereas on other passes only 1 vent was visible. However, it was common that multiple vents were active at any one time. The highest observed rise of a bubble plume in the water column came from the easternmost vent, with the main plume rising 415 meters from the vent to within 175 m of the surface. In some cases, wisps from the main plume rose to heights less than 100 m from the surface. This analysis shows that water column imaging multibeam sonar data can be used as a proxy to determine the level of eruptive activity above submarine volcanoes that have robust CO2 output. We plan to compare this data set to other data sets including hydrophone recordings, ADCP data and ROV visual observations.

Merle, S. G.; Chadwick, W. W.; Embley, R. W.; Doucet, M.

2012-12-01

44

Characteristics of Offshore Hawai';i Island Seismicity and Velocity Structure, including Lo';ihi Submarine Volcano  

NASA Astrophysics Data System (ADS)

The Island of Hawai';i is home to the most active volcanoes in the Hawaiian Islands. The island's isolated nature, combined with the lack of permanent offshore seismometers, creates difficulties in recording small magnitude earthquakes with accuracy. This background offshore seismicity is crucial in understanding the structure of the lithosphere around the island chain, the stresses on the lithosphere generated by the weight of the islands, and how the volcanoes interact with each other offshore. This study uses the data collected from a 9-month deployment of a temporary ocean bottom seismometer (OBS) network fully surrounding Lo';ihi volcano. This allowed us to widen the aperture of earthquake detection around the Big Island, lower the magnitude detection threshold, and better constrain the hypocentral depths of offshore seismicity that occurs between the OBS network and the Hawaii Volcano Observatory's land based network. Although this study occurred during a time of volcanic quiescence for Lo';ihi, it establishes a basis for background seismicity of the volcano. More than 480 earthquakes were located using the OBS network, incorporating data from the HVO network where possible. Here we present relocated hypocenters using the double-difference earthquake location algorithm HypoDD (Waldhauser & Ellsworth, 2000), as well as tomographic images for a 30 km square area around the summit of Lo';ihi. Illuminated by using the double-difference earthquake location algorithm HypoDD (Waldhauser & Ellsworth, 2000), offshore seismicity during this study is punctuated by events locating in the mantle fault zone 30-50km deep. These events reflect rupture on preexisting faults in the lower lithosphere caused by stresses induced by volcano loading and flexure of the Pacific Plate (Wolfe et al., 2004; Pritchard et al., 2007). Tomography was performed using the double-difference seismic tomography method TomoDD (Zhang & Thurber, 2003) and showed overall velocities to be slower than the regional velocity model (HG50; Klein, 1989) in the shallow lithosphere above 16 km depth. This is likely a result of thick deposits of volcaniclastic sediments and fractured pillow basalts that blanket the southern submarine flank of Mauna Loa, upon which Lo';ihi is currently superimposing (Morgan et al., 2003). A broad, low-velocity anomaly was observed from 20-40 km deep beneath the area of Pahala, and is indicative of the central plume conduit that supplies magma to the active volcanoes. A localized high-velocity body is observed 4-6 km deep beneath Lo';ihi's summit, extending 10 km to the North and South. Oriented approximately parallel to Lo';ihi's active rift zones, this high-velocity body is suggestive of intrusion in the upper crust, similar to Kilauea's high-velocity rift zones.

Merz, D. K.; Caplan-Auerbach, J.; Thurber, C. H.

2013-12-01

45

Bacterial diversity in Fe-rich hydrothermal sediments at two South Tonga Arc submarine volcanoes.  

PubMed

Seafloor iron oxide deposits are a common feature of submarine hydrothermal systems. Morphological study of these deposits has led investigators to suggest a microbiological role in their formation, through the oxidation of reduced Fe in hydrothermal fluids. Fe-oxidizing bacteria, including the recently described Zetaproteobacteria, have been isolated from a few of these deposits but generally little is known about the microbial diversity associated with this habitat. In this study, we characterized bacterial diversity in two Fe oxide samples collected on the seafloor of Volcanoes 1 and 19 on the South Tonga Arc. We were particularly interested in confirming the presence of Zetaproteobacteria at these two sites and in documenting the diversity of groups other than Fe oxidizers. Our results (small subunit rRNA gene sequence data) showed a surprisingly high bacterial diversity, with 150 operational taxonomic units belonging to 19 distinct taxonomic groups. Both samples were dominated by Zetaproteobacteria Fe oxidizers. This group was most abundant at Volcano 1, where sediments were richer in Fe and contained more crystalline forms of Fe oxides. Other groups of bacteria found at these two sites include known S- and a few N-metabolizing bacteria, all ubiquitous in marine environments. The low similarity of our clones with the GenBank database suggests that new species and perhaps new families were recovered. The results of this study suggest that Fe-rich hydrothermal sediments, while dominated by Fe oxidizers, can be exploited by a variety of autotrophic and heterotrophic micro-organisms. PMID:20533949

Forget, N L; Murdock, S A; Juniper, S K

2010-12-01

46

Methane discharge from a deep-sea submarine mud volcano into the upper water column by gas hydrate-coated methane bubbles  

Microsoft Academic Search

The assessment of climate change factors includes a constraint of methane sources and sinks. Although marine geological sources are recognized as significant, unfortunately, most submarine sources remain poorly quantified. Beside cold vents and coastal anoxic sediments, the large number of submarine mud volcanoes (SMV) may contribute significantly to the oceanic methane pool. Recent research suggests that methane primarily released diffusively

Eberhard J. Sauter; Sergey I. Muyakshin; Jean-Luc Charlou; Michael Schlüter; Antje Boetius; Kerstin Jerosch; Ellen Damm; Jean-Paul Foucher; Michael Klages

2006-01-01

47

Deployment of a seismic array for volcano monitoring during the ongoing submarine eruption at El Hierro, Canary Islands  

NASA Astrophysics Data System (ADS)

On 17 July 2011 there was an important increase of the seismic activity at El Hierro (Canary Islands, Spain). This increase was detected by the Volcano Monitoring Network (Spanish national seismic network) run by the Instituto Geográfico Nacional (IGN). As a consequence, the IGN immediately deployed a dense, complete monitoring network that included seismometers, GPS stations, geochemical equipment, magnetometers, and gravity meters. During the first three months of activity, the seismic network recorded over ten thousand volcano-tectonic earthquakes, with a maximum magnitude of 4.6. On 10 October 2011 an intense volcanic tremor started. It was a monochromatic signal, with variable amplitude and frequency content centered at about 1-2 Hz. The tremor onset was correlated with the initial stages of the submarine eruption that occurred from a vent located south of El Hierro island, near the village of La Restinga. At that point the IGN, in collaboration with the Instituto Andaluz de Geofísica, deployed a seismic array intended for volcanic tremor monitoring and analysis. The seismic array is located about 7 km NW of the submarine vent. It has a 12-channel, 24-bit data acquisition system sampling each channel at 100 sps. The array is composed by 1 three-component and 9 vertical-component seismometers, distributed in a flat area with an aperture of 360 m. The data provided by the seismic array are going to be processed using two different approaches: (1) near-real-time, to produce information that can be useful in the management of the volcanic crisis; and (2) detailed investigations, to study the volcanic tremor characteristics and relate them to the eruption dynamics. At this stage we are mostly dedicated to produce fast, near-real-time estimates. Preliminary results have been obtained using the maximum average cross-correlation method. They indicate that the tremor wavefronts are highly coherent among array stations and propagate across the seismic array with an apparent slowness of ~0.8 s/km and a back-azimuth of 135°N. These estimates have remained approximately constant since the onset of volcanic tremor, indicating a unique source and thus a single, continuing eruptive center.

Abella, R.; Almendros, J.; Carmona, E.; Martin, R.

2012-04-01

48

Volcanic Risk Perception in Five Communities Located near the Chichón Volcano, Northern Chiapas, Mexico  

Microsoft Academic Search

The Chichón volcano (17° 19' N and 93° 15' W) is located in the state of Chiapas, Mexico. This volcano is classified by UNESCO as one of the ten most dangerous volcanos in the world. The eruptions of March and April in 1982 affected at least 51 communities located in the surroundings of the volcano and caused the death of

F. Rodriguez; D. A. Novelo-Casanova

2010-01-01

49

Discovery of an active shallow submarine silicic volcano in the northern Izu-Bonin Arc: volcanic structure and potential hazards of Oomurodashi Volcano (Invited)  

NASA Astrophysics Data System (ADS)

Oomurodashi is a bathymetric high located ~20 km south of Izu-Oshima, an active volcanic island of the northern Izu-Bonin Arc. Using the 200 m bathymetric contour to define its summit dimensions, the diameter of Oomurodashi is ~20 km. Oomurodashi has been regarded as inactive, largely because it has a vast flat-topped summit at 100 - 150 meters below sea level (mbsl). During cruise NT07-15 of R/V Natsushima in 2007, we conducted a dive survey in a small crater, Oomuro Hole, located in the center of the flat-topped summit, using the remotely-operated vehicle (ROV) Hyper-Dolphin. The only heat flow measurement conducted on the floor of Oomuro Hole during the dive recorded an extremely high value of 4,200 mW/m2. Furthermore, ROV observations revealed that the southwestern wall of Oomuro Hole consists of fresh rhyolitic lavas. These findings suggest that Oomurodashi is in fact an active silicic submarine volcano. To confirm this hypothesis, we conducted detailed geological and geophysical ROV Hyper-Dolphin (cruise NT12-19). In addition to further ROV surveys, we carried out single-channel seismic (SCS) surveys across Oomurodashi in order to examine the shallow structures beneath the current edifice. The ROV surveys revealed numerous active hydrothermal vents on the floor of Oomuro Hole, at ~200 mbsl, with maximum water temperature measured at the hydrothermal vents reaching 194°C. We also conducted a much more detailed set of heat flow measurements across the floor of Oomuro Hole, detecting very high heat flows of up to 29,000 mW/m2. ROV observations revealed that the area surrounding Oomuro Hole on the flat-topped summit of Oomurodashi is covered by extensive fresh rhyolitic lava and pumice clasts with minimum biogenetic or manganese cover, suggesting recent eruption(s). These findings strongly indicate that Oomurodashi is an active silicic submarine volcano, with recent eruption(s) occurring from Oomuro Hole. Since the summit of Oomurodashi is in shallow water, it is possible that eruption columns are likely to breach the sea surface and generate subaerial plumes. A ~10 ka pumiceous tephra layer with a similar composition to the rocks recovered during the dives has been discovered in the subaerial outcrops of Izu-Oshima, suggesting that this tephra may have originated from Oomurodashi. The deeper slopes of Oomurodashi are composed of effusive and intrusive rocks that are bimodal in composition, with basaltic dikes and lavas on the northern flank and dacite volcaniclastics on the eastern flank. This suggests that Oomurodashi is a complex of smaller edifices of various magma types, similar to what has been observed at silicic submarine calderas in the southern part of the Izu-Bonin Arc (e.g. Sumisu Caldera; Tani et al., 2008, Bull. Vol.). Furthermore, the SCS surveys revealed the presence of a buried caldera structure, ~8 km in diameter, beneath the flat-topped summit of Oomurodashi, indicating that voluminous and explosive eruptions may have occurred in the past.

Tani, K.; Ishizuka, O.; Nichols, A. R.; Hirahara, Y.; Carey, R.; McIntosh, I. M.; Masaki, Y.; Kondo, R.; Miyairi, Y.

2013-12-01

50

Slope failure and volcanic spreading along the submarine south flank of Kilauea volcano, Hawaii  

NASA Astrophysics Data System (ADS)

New multichannel reflection data and high-resolution bathymetry over the submarine slopes of Kilauea volcano provide evidence for current and prior landsliding, suggesting a dynamic interplay among slope failure, regrowth, and volcanic spreading. Disrupted strata along the upper reaches of Kilauea's flank denote a coherent slump, correlated with the active Hilina slump. The slump comprises mostly slope sediments, underlain by a detachment 3-5 km deep. Extension and subsidence along the upper flank is compensated by uplift and folding of the slump toe, which surfaces about midway down the submarine flank. Uplift of strata forming Papa`u seamount and offset of surface features along the western boundary of Kilauea indicate that the slump has been displaced ˜3 km in a south-southeast direction. This trajectory matches coseismic and continuous ground displacements for the Hilina slump block on land, and contrasts with the southeast vergence of the rest of the creeping south flank. To the northeast, slope sediments are thinned and disrupted within a recessed region of the central flank, demonstrating catastrophic slope failure in the recent past. Debris from the collapsed flank was shed into the moat in front of Kilauea, building an extensive apron. Seaward sliding of Kilauea's flank offscraped these deposits to build an extensive frontal bench. A broad basin formed behind the bench and above the embayed flank. Uplift and back tilting of young basin fill indicate recent, and possibly ongoing, bench growth. The Hilina slump now impinges upon the frontal bench; this buttress may tend to reduce the likelihood of future catastrophic detachment.

Morgan, Julia K.; Moore, Gregory F.; Clague, David A.

2003-09-01

51

Liquid and Emulsified Sulfur in Submarine Solfatara Fields of two Northern Mariana Arc Volcanoes.  

NASA Astrophysics Data System (ADS)

Because elemental sulfur melting point is ca 100 deg C (depend on allotropes and heating rate, S8 triple point temperature: 115 deg C), the evidence of liquid sulfur has been known for many subaerial crater lakes and small ponds in geothermal regions throughout the world. But the milky nature of water (sulfur-in- water emulsion in limited water mass) prohibited the direct observation of on-going processes at the bottom of these subaerial lakes. In the passive degassing environment at the summit craters of Daikoku and Nikko Seamounts of the northern Mariana Arc, the continuous flushing of sulfur emulsion by seawater allowed us to observe on- going submarine solfatara processes and associated chemistry through dives with ROVs during the NT05-18 cruise (JAMSTEC R/V Natsushima and ROV hyper-Dolphin) and the Submarine Ring of Fire 2006 cruise (R/V Melville and ROV JASON II). A higher viscosity for liquid elemental sulfur relative to that of seawater, as well as a limited stability of sulfur emulsion (aqueous sulfur sol) at high temperatures in electrolyte solution (seawater), ensures limited mobility of liquid sulfur in the conduits of hydrothermal vents. The subseafloor boiling depth of hydrothermal fluid limits the locus of any liquid sulfur reservoir. It was observed in an exposed liquid sulfur pond that the penetration of gas bubbles (mostly CO2) created sulfur emulsion while collapsing liquid sulfur film between seawater and gas bubbles. Liquid sulfur pits, encrusted sulfur, liquid sulfur fountain structure, sulfur stalactites and stalagmites, mini-pillow lava-like sulfur flows, accretionary sulfur lapilli and sulfur deltas were also observed at the summits of two volcanoes. Note: Solfatara: Italian. A type of fumarole, the gases of which are characteristically sulfurous. In 'Glossary of geology.'

Nakamura, K.; Embley, R. W.; Chadwick, W. W.; Butterfield, D. A.; Takano, B.; Resing, J. A.; de Ronde, C. E.; Lilley, M. D.; Lupton, J. E.; Merle, S. G.; Inagaki, F.

2006-12-01

52

Hydrothermal mineralization at Kick'em Jenny submarine volcano in the Lesser Antilles island arc  

NASA Astrophysics Data System (ADS)

Kick 'em Jenny (KeJ) is an active submarine volcano located in the Lesser Antilles island arc, ~7.5 km northwest of Grenada. Of the twelve eruptions detected since 1939, most have been explosive as evidenced by eyewitness accounts in 1939, 1974, and 1988 and the dominance of explosive eruption products recovered by dredging. In 2003, vigorous hydrothermal activity was observed in the crater of KeJ. Video footage taken by a remotely operated vehicle (ROV) during the cruise RB-03-03 of the R/V Ronald Brown documented the venting of a vapor phase in the form of bubbles that ascended through the water column and a clear fluid phase in the form of shimmering water. The shimmering water generally ascended through the water column but can also been seen flowing down gradient from a fissure at the top of a fine-grained sediment mound. These fine-grained sediment mounds are the only structure associated with hydrothermal venting; spire or chimney structures were not observed. Hydrothermal venting was also observed coming from patches of coarse-grained volcaniclastic sediment on the crater floor and from talus slopes around the perimeter of the crater. Samples were collected from these areas and from areas void of hydrothermal activity. XRD and ICPMS analyses of bulk sediment were carried out to investigate the geochemical relationships between sediment types. Sediment samples from the hydrothermal mound structures are comprised of the same components (plagioclase, amphibole, pyroxene, and scoria) as sediment samples from areas void of hydrothermal activity (primary volcaniclastic sediment) in the 500-63 ?m size range. High resolution grain size analyses show that >78% of sediment in the hydrothermal mound samples are between 63-2 ?m with 6-20% clay sized (<2 ?m) whereas <40% of the primary volcaniclastic sediment is between 63-2 ?m with ~2% clay sized. The presence of clay minerals (smectite, illite, talc, and I/S mixed layer) in the hydrothermal mound samples was confirmed x-ray diffraction analysis. Differences in major oxide composition of the two sediment types (depletion in Al2O3 but enrichments in MgO and Fe2O3* in the mound sample relative to primary volcaniclastic sediment) suggest that mound sediment has experienced hydrothermal alteration/mineralization. Elevated concentrations of As, Sb and Cu in the mound sediment also indicate a strong hydrothermal contribution. The bulk composition of the mound sediment can be reasonably modeled as a mixture of ~78% primary volcaniclastic sediment, ~30% alteration clay minerals, and ~2% pyrite. The percentage of clay required in the model is ~10% greater than the fraction (~20%) observed in the hydrothermal mound sample but some of the alteration products may consist of larger grains that have not been analyzed individually.

Olsen, R.; Carey, S.; Sigurdsson, H.; Cornell, W. C.

2011-12-01

53

The submarine volcano eruption at the island of El Hierro: physical-chemical perturbation and biological response  

NASA Astrophysics Data System (ADS)

On October 10 2011 an underwater eruption gave rise to a novel shallow submarine volcano south of the island of El Hierro, Canary Islands, Spain. During the eruption large quantities of mantle-derived gases, solutes and heat were released into the surrounding waters. In order to monitor the impact of the eruption on the marine ecosystem, periodic multidisciplinary cruises were carried out. Here, we present an initial report of the extreme physical-chemical perturbations caused by this event, comprising thermal changes, water acidification, deoxygenation and metal-enrichment, which resulted in significant alterations to the activity and composition of local plankton communities. Our findings highlight the potential role of this eruptive process as a natural ecosystem-scale experiment for the study of extreme effects of global change stressors on marine environments. (A) Natural color composite from the MEdium Resolution Imaging Spectrometer (MERIS) instrument aboard ENVISAT Satellite (European Space Agency), (November 9, 2011 at 14:45 UTC). Remote sensing data have been used to monitor the evolution of the volcanic emissions, playing a fundamental role during field cruises in guiding the Spanish government oceanographic vessel to the appropriate sampling areas. The inset map shows the position of Canary Islands west of Africa and the study area (solid white box). (B) Location of the stations carried out from November 2011 to February 2012 at El Hierro. Black lines denote transects A-B and C-D.

Fraile-Nuez, E.; Santana-Casiano, J.; Gonzalez-Davila, M.

2013-12-01

54

40Ar/39Ar geochronology of submarine Mauna Loa volcano, Hawaii  

NASA Astrophysics Data System (ADS)

A major impediment to our understanding of the nature and structure of the Hawaiian plume, and evaluating the competing plume models has been a lack of thick stratigraphic sections from which to obtain long temporal records of magmatic history. The Hawaii Scientific Drilling Project (HSDP) made a significant advance towards solving this problem by documenting the long-term magmatic evolution of Mauna Kea volcano on the Kea side of the plume. To evaluate comparable long-term magmatic history on the Loa side of the plume we collected a stratigraphically controlled sample suite using Jason and Pisces dives from three vertical transects of the 1.6 km high Kae Lae landslide scarp cut into Mauna Loa’s submarine southwest rift zone (SWR). We have undertaken an 40Ar/39Ar investigation of Mauna Loa’s growth history to integrate new geochronologic constraints with geochemical, and isotopic data, illuminating temporal trends within the Hawaiian plume. Obtaining precise 40Ar/39Ar ages from tholeiitic lavas younger than 500 ka containing only 0.2-0.6 wt.% K2O is challenging due to the extremely low radiogenic 40Ar contents. Furnace incremental heating experiments of groundmass separated from 15 submarine lavas have yielded four new age determinations (a 27% success rate). These four lavas give concordant age spectra with plateau and isochron ages that agree with stratigraphy. We also analyzed two previously-dated subaerial Mauna Kea tholeiites from the HSDP-2 drill core, to assess inter-laboratory reproducibility and calibrate our results to those obtained for the core. Two experiments on sample SR413-4.0 and one experiment from SR781-21.2 gave weighted mean plateau ages of 364 ± 95 ka and 473 ± 109, respectively, which are indistinguishable from the published 40Ar/39Ar ages of 390 ± 70 ka and 482 ± 67. Although Sharp and Renne (2005) preferred isochron ages for the submarine Mauna Kea tholeiites recovered from HSDP, we find that submarine Mauna Loa lavas contain trapped argon with a 40Ar/36Ar ratio that is indistinguishable from the atmospheric value of 295.5. Therefore, we consider the plateau ages to provide the most precise estimate of time elapsed since eruption. Lavas from 857, 1753, and 2112 mbsl give indistinguishable plateau ages of 473 ± 29, 463 ± 33, and 472 ± 107, respectively, implying an extraordinary period of lava accumulation. If correct, this implies that ~1300 m of lava was emplaced on the SWR at a rate far exceeding that proposed in previous accumulation models for Mauna Loa or Mauna Kea, possibly correlating with the peak of the shield-building stage. Three experiments from a more K-rich lava (0.67 wt. % K2O) near the top of the landslide scarp gave a weighted mean plateau age of 193 ± 16 ka, indicating a marked decline in eruption rates on this part of the SWR.

Jicha, B.; Rhodes, J. M.; Singer, B. S.; Vollinger, M. J.; Garcia, M. O.

2009-12-01

55

Dive and Explore: An Interactive Web Visualization that Simulates Making an ROV Dive to an Active Submarine Volcano  

NASA Astrophysics Data System (ADS)

Several years ago we created an exciting and engaging multimedia exhibit for the Hatfield Marine Science Center that lets visitors simulate making a dive to the seafloor with the remotely operated vehicle (ROV) named ROPOS. The exhibit immerses the user in an interactive experience that is naturally fun but also educational. The public display is located at the Hatfield Marine Science Visitor Center in Newport, Oregon. We are now completing a revision to the project that will make this engaging virtual exploration accessible to a much larger audience. With minor modifications we will be able to put the exhibit onto the world wide web so that any person with internet access can view and learn about exciting volcanic and hydrothermal activity at Axial Seamount on the Juan de Fuca Ridge. The modifications address some cosmetic and logistic ISSUES confronted in the museum environment, but will mainly involve compressing video clips so they can be delivered more efficiently over the internet. The web version, like the museum version, will allow users to choose from 1 of 3 different dives sites in the caldera of Axial Volcano. The dives are based on real seafloor settings at Axial seamount, an active submarine volcano on the Juan de Fuca Ridge (NE Pacific) that is also the location of a seafloor observatory called NeMO. Once a dive is chosen, then the user watches ROPOS being deployed and then arrives into a 3-D computer-generated seafloor environment that is based on the real world but is easier to visualize and navigate. Once on the bottom, the user is placed within a 360 degree panorama and can look in all directions by manipulating the computer mouse. By clicking on markers embedded in the scene, the user can then either move to other panorama locations via movies that travel through the 3-D virtual environment, or they can play video clips from actual ROPOS dives specifically related to that scene. Audio accompanying the video clips informs the user where they are going or what they are looking at. After the user is finished exploring the dive site they end the dive by leaving the bottom and watching the ROV being recovered onto the ship at the surface. Within the three simulated dives there are a total of 6 arrival and departure movies, 7 seafloor panoramas, 12 travel movies, and 23 ROPOS video clips. This virtual exploration is part of the NeMO web site and will be at this URL http://www.pmel.noaa.gov/vents/dive.html

Weiland, C.; Chadwick, W. W.

2004-12-01

56

Seismic tomography reveals magma chamber location beneath Uturuncu volcano (Bolivia)  

NASA Astrophysics Data System (ADS)

Uturuncu volcano belongs to the Altiplano-Puna Volcanic Complex in the central Andes, the product of an ignimbrite ''flare-up''. The region has been the site of large-scale silicic magmatism since 10 Ma, producing 10 major eruptive calderas and edifices, some of which are multiple-eruption resurgent complexes as large as the Yellowstone or Long Valley caldera. Satellite measurements show that the hill has been rising more than half an inch a year for almost 20 years, suggesting that the Uturuncu volcano, which has erupted last time more than 300,000 years ago, is steadily inflating, which makes it fertile ground for study. In 2009 an international multidisciplinary team formed a project called PLUTONS to study Uturuncu. Under this project a 100 km wide seismic network was set around the volcano by seismologists from University of Alaska Fairbanks. Local seismicity is well distributed and provides constraints on the shallow crust. Ray paths from earthquakes in the subducting slab complement this with steep ray paths that sample the deeper crust. Together the shallow and deep earthquakes provide strong 3D coverage of Uturuncu and the surrounding region. To study the deformation source beneath the volcano we performed simultaneous tomographic inversion for the Vp and Vs anomalies and source locations, using the non-linear passive source tomographic code, LOTOS. We estimated both P and S wave velocity structures beneath the entire Uturuncu volcano by using arrival times of P and S waves from more than 600 events registered by 33 stations. To show the reliability of the results, we performed a number of different tests, including checkerboard synthetic tests and tests with odd/even data. Obtained Vp/Vs ratio distribution shows increased values beneath the south Uturuncu, at a depth of about 15 km. We suggest the high ratio anomaly is caused by partial melt, presented in expanding magma chamber, responsible for the volcano inflation. The resulting Vp, Vs and the ratio reveal the paths of the ascending fluids and melts, feeding the magma chamber. This work was partly supported by Project #7.3 of BES RAS and Project #14-05-31176 mola of RFBR.

Kukarina, Ekaterina; West, Michael; Koulakov, Ivan

2014-05-01

57

Vailulu'u Seamount, Samoa: Life and death on an active submarine volcano.  

PubMed

Submersible exploration of the Samoan hotspot revealed a new, 300-m-tall, volcanic cone, named Nafanua, in the summit crater of Vailulu'u seamount. Nafanua grew from the 1,000-m-deep crater floor in <4 years and could reach the sea surface within decades. Vents fill Vailulu'u crater with a thick suspension of particulates and apparently toxic fluids that mix with seawater entering from the crater breaches. Low-temperature vents form Fe oxide chimneys in many locations and up to 1-m-thick layers of hydrothermal Fe floc on Nafanua. High-temperature (81 degrees C) hydrothermal vents in the northern moat (945-m water depth) produce acidic fluids (pH 2.7) with rising droplets of (probably) liquid CO(2). The Nafanua summit vent area is inhabited by a thriving population of eels (Dysommina rugosa) that feed on midwater shrimp probably concentrated by anticyclonic currents at the volcano summit and rim. The moat and crater floor around the new volcano are littered with dead metazoans that apparently died from exposure to hydrothermal emissions. Acid-tolerant polychaetes (Polynoidae) live in this environment, apparently feeding on bacteria from decaying fish carcasses. Vailulu'u is an unpredictable and very active underwater volcano presenting a potential long-term volcanic hazard. Although eels thrive in hydrothermal vents at the summit of Nafanua, venting elsewhere in the crater causes mass mortality. Paradoxically, the same anticyclonic currents that deliver food to the eels may also concentrate a wide variety of nektonic animals in a death trap of toxic hydrothermal fluids. PMID:16614067

Staudigel, Hubert; Hart, Stanley R; Pile, Adele; Bailey, Bradley E; Baker, Edward T; Brooke, Sandra; Connelly, Douglas P; Haucke, Lisa; German, Christopher R; Hudson, Ian; Jones, Daniel; Koppers, Anthony A P; Konter, Jasper; Lee, Ray; Pietsch, Theodore W; Tebo, Bradley M; Templeton, Alexis S; Zierenberg, Robert; Young, Craig M

2006-04-25

58

Vailulu'u Seamount, Samoa: Life and death on an active submarine volcano  

PubMed Central

Submersible exploration of the Samoan hotspot revealed a new, 300-m-tall, volcanic cone, named Nafanua, in the summit crater of Vailulu’u seamount. Nafanua grew from the 1,000-m-deep crater floor in <4 years and could reach the sea surface within decades. Vents fill Vailulu’u crater with a thick suspension of particulates and apparently toxic fluids that mix with seawater entering from the crater breaches. Low-temperature vents form Fe oxide chimneys in many locations and up to 1-m-thick layers of hydrothermal Fe floc on Nafanua. High-temperature (81°C) hydrothermal vents in the northern moat (945-m water depth) produce acidic fluids (pH 2.7) with rising droplets of (probably) liquid CO2. The Nafanua summit vent area is inhabited by a thriving population of eels (Dysommina rugosa) that feed on midwater shrimp probably concentrated by anticyclonic currents at the volcano summit and rim. The moat and crater floor around the new volcano are littered with dead metazoans that apparently died from exposure to hydrothermal emissions. Acid-tolerant polychaetes (Polynoidae) live in this environment, apparently feeding on bacteria from decaying fish carcasses. Vailulu’u is an unpredictable and very active underwater volcano presenting a potential long-term volcanic hazard. Although eels thrive in hydrothermal vents at the summit of Nafanua, venting elsewhere in the crater causes mass mortality. Paradoxically, the same anticyclonic currents that deliver food to the eels may also concentrate a wide variety of nektonic animals in a death trap of toxic hydrothermal fluids.

Staudigel, Hubert; Hart, Stanley R.; Pile, Adele; Bailey, Bradley E.; Baker, Edward T.; Brooke, Sandra; Connelly, Douglas P.; Haucke, Lisa; German, Christopher R.; Hudson, Ian; Jones, Daniel; Koppers, Anthony A. P.; Konter, Jasper; Lee, Ray; Pietsch, Theodore W.; Tebo, Bradley M.; Templeton, Alexis S.; Zierenberg, Robert; Young, Craig M.

2006-01-01

59

A Geochemical Study of Magmatic Processes and Evolution along the Submarine Southwest Rift zone of Mauna Loa Volcano, Hawaii  

NASA Astrophysics Data System (ADS)

Mauna Loa's southwest rift zone (SWR) extends for 102 km from its summit caldera, at an elevation of 4,170 m above sea level, to submarine depths of over 4,500 m. About 65% of the rift zone is subaerial and 35% submarine. Recent sampling with the Jason II submersible of the `mile-high' (1800 m) Ka Lae submarine landslide scarp and the deepest section of the rift zone, in conjunction with previous submersible and dredge-haul collecting, provides petrological and geochemical understanding of rift zone processes, as well as a record of Mauna Loa's eruptive history extending back about 400 ka. The major and trace element trends of the submarine lavas are remarkably similar to those of historical and young prehistoric lavas (<31 ka) erupted along the subaerial SWR. We take this to imply that magma-forming processes have remained relatively constant over much of the volcano's recorded eruptive history. However, the distribution of samples along these trends has varied, and is correlated with elevation. There are very few picrites (>12% MgO) among the subaerial lavas, and compositions tend to cluster around 6.8-8.0% MgO. In contrast, picritic lavas are extremely abundant in the submarine samples, increasing in frequency with depth, especially below 1200 m. These observations support earlier interpretations that the submarine lavas are derived directly from deeper levels in the magma column, and that magmas from a shallow, steady-state, magma reservoir are of uncommon at these depths. Isotopic ratios of Pb and Sr in the submarine lavas, in conjunction with Nb/Y and Zr/Nb ratios, extend from values that are identical with subaerial historical Mauna Loa lavas to lavas with markedly lower 87Sr/86Sr and higher 206Pb/204Pb isotopic ratios. As yet, we see no correlation with depth or age, but the implications are that, in the past, the plume source of Mauna Loa magmas was more variable than in the last 31 ka, and contained a greater proportion of the Kea component. *Team members also include: H. Guillou, CEA/CNRS, France; M. Kurz and D. Fornari, WHOI; M. Norman and V. Bennett, ANU, Australia; S. Schilling, USGS; M. Chapman, Morehead State University; D. Wanless and K. Kolysko, University of Hawaii.

Rhodes, J. M.; Garcia, M. O.; Weis, D.; Trusdell, F. A.; Vollinger, M. J.

2003-12-01

60

Volcanic construction of submarine Kermadec arc volcanoes from near-bottom sidescan sonar data collected by the Sentry AUV  

NASA Astrophysics Data System (ADS)

Seafloor mapping in the deep ocean has benefitted greatly from the advent and now routine use of autonomous underwater vehicles (AUVs) to collect areally extensive near-bottom bathymetric, photographic, hydrographic, and magnetic data. For geologic investigations, AUV-derived data is often supplemented by near-bottom sidescan sonar backscatter data that provides information on seafloor substrate (e.g., sediment/bare rock) and roughness. High-frequency sidescan sonar data with comparable resolution to AUV-derived bathymetry is typically collected by deep-towed instruments at altitudes <100 m. This approach has limited use in rough terrain as rapid depth changes in towed-vehicles can significantly degrade sidescan sonar data quality. This limitation certainly applies to arc volcanoes where regional slopes in excess of 25 degrees are present on volcano flanks and much greater local slopes due steep-walled calderas and resurgent domes are common. Here we report the first deployment of a dual-frequency sidescan sonar system (Edgetech 2200M 120/410 kHz) on the National Deep Submergence Facility AUV Sentry, which can easily operate in rough terrain. Sidescan sonar data was collected over three submarine volcanoes in the Kermadec Arc (Brothers, Healy, Rumble III) on a cruise sponsored by the Institute of Geological and Nuclear Science, New Zealand. Sentry operated at ~40 m altitude with track spacing of 50-100 m. Sonar imagery from the 410 kHz channel has a spatial resolution of ~20 cm/pixel. To our knowledge, these are the first near-bottom, high-frequency sidescan sonar data collected at submarine arc volcanoes. We use these data to evaluate the type (explosive, effusive), size, and relative age of the deposits that make up these volcanic edifices based on acoustic backscatter intensity, along with ground-truthing from deep-towed photographic surveys. Relative to existing multibeam and sidescan sonar backscatter data in similar settings, the Sentry-collected sidescan sonar can resolve much smaller scale features and thus generate a higher-fidelity record of the processes responsible for arc volcano construction and evolution than was previously possible.

Soule, S. A.; de Ronde, C. E.; Leybourne, M. I.; Caratori Tontini, F.; Kaiser, C. L.; Kurras, G. J.; Kinsey, J. C.; Yoerger, D. R.

2011-12-01

61

Internal structure of Puna Ridge: evolution of the submarine East Rift Zone of Kilauea Volcano, Hawai ?i  

NASA Astrophysics Data System (ADS)

Multichannel seismic reflection, sonobuoy, gravity and magnetics data collected over the submarine length of the 75 km long Puna Ridge, Hawai ?i, resolve the internal structure of the active rift zone. Laterally continuous reflections are imaged deep beneath the axis of the East Rift Zone (ERZ) of Kilauea Volcano. We interpret these reflections as a layer of abyssal sediments lying beneath the volcanic edifice of Kilauea. Early arrival times or 'pull-up' of sediment reflections on time sections imply a region of high P-wave velocity ( Vp) along the submarine ERZ. Refraction measurements along the axis of the ridge yield Vp values of 2.7-4.85 km/s within the upper 1 km of the volcanic pile and 6.5-7 km/s deeper within the edifice. Few coherent reflections are observed on seismic reflection sections within the high-velocity area, suggesting steeply dipping dikes and/or chaotic and fractured volcanic materials. Southeastward dipping reflections beneath the NW flank of Puna Ridge are interpreted as the buried flank of the older Hilo Ridge, indicating that these two ridges overlap at depth. Gravity measurements define a high-density anomaly coincident with the high-velocity region and support the existence of a complex of intrusive dikes associated with the ERZ. Gravity modeling shows that the intrusive core of the ERZ is offset to the southeast of the topographic axis of the rift zone, and that the surface of the core dips more steeply to the northwest than to the southeast, suggesting that the dike complex has been progressively displaced to the southeast by subsequent intrusions. The gravity signature of the dike complex decreases in width down-rift, and is absent in the distal portion of the rift zone. Based on these observations, and analysis of Puna Ridge bathymetry, we define three morphological and structural regimes of the submarine ERZ, that correlate to down-rift changes in rift zone dynamics and partitioning of intrusive materials. We propose that these correspond to evolutionary stages of developing rift zones, which may partially control volcano growth, mobility, and stability, and may be observable at many other oceanic volcanoes.

Leslie, Stephen C.; Moore, Gregory F.; Morgan, Julia K.

2004-01-01

62

Submarine geology of the Hilina slump and morpho-structural evolution of Kilauea volcano, Hawaii  

Microsoft Academic Search

Marine geophysical data, including SEA BEAM bathymetry, HAWAII MR1 sidescan, and seismic reflection profiles, along with recent robot submersible observations and samples, were acquired over the offshore continuation of the mobile Kilauea volcano south flank. This slope comprises the three active hot spot volcanoes Mauna Loa, Kilauea, and Loihi seamount and is the locus of the Hawaiian hot spot. The

John R. Smith; Alexander Malahoff; Alexander N. Shor

1999-01-01

63

The submarine volcano eruption at the island of El Hierro: physical-chemical perturbation and biological response  

PubMed Central

On October 10 2011 an underwater eruption gave rise to a novel shallow submarine volcano south of the island of El Hierro, Canary Islands, Spain. During the eruption large quantities of mantle-derived gases, solutes and heat were released into the surrounding waters. In order to monitor the impact of the eruption on the marine ecosystem, periodic multidisciplinary cruises were carried out. Here, we present an initial report of the extreme physical-chemical perturbations caused by this event, comprising thermal changes, water acidification, deoxygenation and metal-enrichment, which resulted in significant alterations to the activity and composition of local plankton communities. Our findings highlight the potential role of this eruptive process as a natural ecosystem-scale experiment for the study of extreme effects of global change stressors on marine environments.

Fraile-Nuez, E.; Gonzalez-Davila, M.; Santana-Casiano, J. M.; Aristegui, J.; Alonso-Gonzalez, I. J.; Hernandez-Leon, S.; Blanco, M. J.; Rodriguez-Santana, A.; Hernandez-Guerra, A.; Gelado-Caballero, M. D.; Eugenio, F.; Marcello, J.; de Armas, D.; Dominguez-Yanes, J. F.; Montero, M. F.; Laetsch, D. R.; Velez-Belchi, P.; Ramos, A.; Ariza, A. V.; Comas-Rodriguez, I.; Benitez-Barrios, V. M.

2012-01-01

64

The submarine volcano eruption at the island of El Hierro: physical-chemical perturbation and biological response  

NASA Astrophysics Data System (ADS)

On October 10 2011 an underwater eruption gave rise to a novel shallow submarine volcano south of the island of El Hierro, Canary Islands, Spain. During the eruption large quantities of mantle-derived gases, solutes and heat were released into the surrounding waters. In order to monitor the impact of the eruption on the marine ecosystem, periodic multidisciplinary cruises were carried out. Here, we present an initial report of the extreme physical-chemical perturbations caused by this event, comprising thermal changes, water acidification, deoxygenation and metal-enrichment, which resulted in significant alterations to the activity and composition of local plankton communities. Our findings highlight the potential role of this eruptive process as a natural ecosystem-scale experiment for the study of extreme effects of global change stressors on marine environments.

Fraile-Nuez, Eugenio; Magdalena Santana-Casiano, J.; González-Dávila, Melchor

2014-05-01

65

Viral infections stimulate the metabolism and shape prokaryotic assemblages in submarine mud volcanoes.  

PubMed

Mud volcanoes are geological structures in the oceans that have key roles in the functioning of the global ecosystem. Information on the dynamics of benthic viruses and their interactions with prokaryotes in mud volcano ecosystems is still completely lacking. We investigated the impact of viral infection on the mortality and assemblage structure of benthic prokaryotes of five mud volcanoes in the Mediterranean Sea. Mud volcano sediments promote high rates of viral production (1.65-7.89 × 10(9) viruses g(-1) d(-1)), viral-induced prokaryotic mortality (VIPM) (33% cells killed per day) and heterotrophic prokaryotic production (3.0-8.3 ?gC g(-1) d(-1)) when compared with sediments outside the mud volcano area. The viral shunt (that is, the microbial biomass converted into dissolved organic matter as a result of viral infection, and thus diverted away from higher trophic levels) provides 49 mgC m(-2) d(-1), thus fuelling the metabolism of uninfected prokaryotes and contributing to the total C budget. Bacteria are the dominant components of prokaryotic assemblages in surface sediments of mud volcanoes, whereas archaea dominate the subsurface sediment layers. Multivariate multiple regression analyses show that prokaryotic assemblage composition is not only dependant on the geochemical features and processes of mud volcano ecosystems but also on synergistic interactions between bottom-up (that is, trophic resources) and top-down (that is, VIPM) controlling factors. Overall, these findings highlight the significant role of the viral shunt in sustaining the metabolism of prokaryotes and shaping their assemblage structure in mud volcano sediments, and they provide new clues for our understanding of the functioning of cold-seep ecosystems. PMID:22170423

Corinaldesi, Cinzia; Dell'Anno, Antonio; Danovaro, Roberto

2012-06-01

66

Viral infections stimulate the metabolism and shape prokaryotic assemblages in submarine mud volcanoes  

PubMed Central

Mud volcanoes are geological structures in the oceans that have key roles in the functioning of the global ecosystem. Information on the dynamics of benthic viruses and their interactions with prokaryotes in mud volcano ecosystems is still completely lacking. We investigated the impact of viral infection on the mortality and assemblage structure of benthic prokaryotes of five mud volcanoes in the Mediterranean Sea. Mud volcano sediments promote high rates of viral production (1.65–7.89 × 109?viruses?g?1?d?1), viral-induced prokaryotic mortality (VIPM) (33% cells killed per day) and heterotrophic prokaryotic production (3.0–8.3??gC?g?1?d?1) when compared with sediments outside the mud volcano area. The viral shunt (that is, the microbial biomass converted into dissolved organic matter as a result of viral infection, and thus diverted away from higher trophic levels) provides 49?mgC?m?2?d?1, thus fuelling the metabolism of uninfected prokaryotes and contributing to the total C budget. Bacteria are the dominant components of prokaryotic assemblages in surface sediments of mud volcanoes, whereas archaea dominate the subsurface sediment layers. Multivariate multiple regression analyses show that prokaryotic assemblage composition is not only dependant on the geochemical features and processes of mud volcano ecosystems but also on synergistic interactions between bottom-up (that is, trophic resources) and top-down (that is, VIPM) controlling factors. Overall, these findings highlight the significant role of the viral shunt in sustaining the metabolism of prokaryotes and shaping their assemblage structure in mud volcano sediments, and they provide new clues for our understanding of the functioning of cold-seep ecosystems.

Corinaldesi, Cinzia; Dell'Anno, Antonio; Danovaro, Roberto

2012-01-01

67

1891 Submarine eruption of Foerstner volcano (Pantelleria, Sicily) : insights into the vent structure of basaltic balloon eruptions  

NASA Astrophysics Data System (ADS)

Numerous shallow water basaltic eruptions have produced abundant floating scoria up to several meters in diameter, yet little is known about the conditions that give rise to this unusual style of volcanism. On October 17, 1891, a submarine eruption began 4 kilometers northwest of the island of Pantelleria, Sicily. The eruptive vent was located at a depth of 250 meters along the NW-SE trending Sicily Channel Rift Zone. Evidence for the eruption was provided by the occurrence of hot, scoriaceous lava "balloons" floating on the sea surface along a narrow line about 850-1000 meters long trending along the rift. These extremely vesicular fragments were spherical to ellipsoidal in shape and ranged from <50 to 250 cm in diameter. Remotely Operated Vehicles (ROVs) and existing bathymetric maps have been used to conduct the first detailed investigation of a vent site associated with this unique style of volcanism. In 2011 the ROV Hercules, deployed from the E/V Nautilus, explored the 1891 Foerstner vent using high definition video cameras and produced a high resolution bathymetric map of the area using a BlueView multibeam imaging sonar. Light backscattering and oxidation-reduction potential sensors (MAPRs) were added to Hercules to detect discharge from active venting. ROV video footage has been used in conjunction with the high resolution bathymetric data to construct a geologic map of the vent area based on a variety of facies descriptors, such as abundance of scoria bombs, occurrence of pillow or scoria flow lobes, extent of sediment cover, and presence of spatter-like deposits. Initial results of the mapping have shown that there are two main vents that erupted within the observed area of floating scoria and most likely erupted at the same time as evidenced by similar bulk chemical compositions of recovered samples. Scoria bomb beds and some scoria flow lobes largely cover the suspected main vent, located at a depth of 250 meters. Distinct pillow flow lobes cover the second, previously unknown vent located north of Foerstner volcano at a depth of around 350 meters. Given the close proximity of these two vents, the differences in deposit types may be due to changing eruption style as a function of water depth. The abundant pillow flow lobes observed at the northern vent are most likely the result of more effusive eruptions occurring in deeper water (350 m) whereas the dominantly fragmental nature of material in the main southern vent indicates more vigorous explosive activity at shallower levels (250 m). Based on the nature of deposits found at the vent areas, the basaltic balloons of the 1891 Foerstner eruption are suspected to be a result of both coarse, localized fire fountaining activity and detachment from gas-charged flow lobes. The larger and shallower southern vent area is likely to have been the main source of the basaltic balloons observed on the surface during the 1891 eruption. A review of other historic eruptions that have produced basaltic balloons suggests that this style of activity is likely to be restricted to a rather narrow range of water depths and thus recognition of the distinct deposits produced by this type of activity in ancient deposits could help place important paleodepth constraints on volcaniclastic sequences.

Kelly, J. T.; Carey, S.; Bell, K. L.; Rosi, M.; Marani, M.; Roman, C.; Pistolesi, M.; Baker, E. T.

2012-12-01

68

Description and Location of Tremor at Mt. Erebus Volcano, Antarctica  

NASA Astrophysics Data System (ADS)

From June 2000 till July 2003, 322 distinct episodes of tremor activity have occurred at Mt. Erebus volcano, Antarctica in three extended periods (A. June 2000-October 2001; B. January-December 2002; C. January-July 2003). Period A was characterized by episodes with short duration and small amplitudes (except for a peak in February, 2001). Period B contains the largest amplitudes, reaching a maximum ground velocity of 97.8 microns/s at 0.7 km from the crater on May 21, 2002 (with a reduced displacement of 92.6 cm2, assuming a source at sea level (3.7 km below the summit), and purely body waves). The May, 2002 activity climax was followed by long-lasting and smaller-amplitude tremor episodes lasting until December 2002, and followed later by period C. Erebus tremor exhibits a large variation in duration, amplitude, and frequency content. Three general categories of tremor have been recognized based on predominant characteristics: harmonic (91%), chaotic (6%) and rapid-fire (3%). Within single episodes, events frequently show transitions between these types. The tremor shows no clear association with activity observed in the persistent convecting phonolite lave lake or adjacent vents. Since tremor commenced strombolian eruption frequency has declined, although the cause of this is unknown and is probably related to changes in upper-conduit geometry and not to the tremor. The precise location of these non-transient signals is difficult, and source locations were estimated using several different methods. A first-order approximation was carried out by contouring isoseismal curves and fitting real and theoretical attenuation curves. We also applied envelope cross-correlation, semblance, and spectrogram cross-correlation techniques. Results from the best harmonic and rapid-fire tremor source solutions suggest the presence of at least two distinct deep tremor sources located between 3 to 9 km beneath the summit plateau. We will discuss assumptions, methodology, and implications of the activity and source locations for the evolving dynamics of Erebus.

Ruiz, M. C.; Aster, R. C.; Kyle, P. R.; Wilson, D. C.

2003-12-01

69

SeaMARC 2 side-scan images of submarine volcanoes: Potential analogues for Venus  

NASA Technical Reports Server (NTRS)

The Earth's surface beneath the oceans may be very similar, in terms of ambient pressures, to the surface of Venus. For that reason it is particularly important for geologists studying the surface of Venus to understand the processes which form features on the floors of the oceans. With the SeaMARC 2 seafloor mapping system, it is possible to view a swath of seafloor that is 10 km wide (about 6.2 mi). Side scan images of the Mariana region show that volcanoes of the island arc are more complicated than previously realized and that features of the fore-arc region, which resemble volcanoes morphologically, may result from processes other than volcanism. By comparing data obtained from the ocean floor with radar images of Venus, the geological evolution of that planet may be more fully understood.

Fryer, P.; Hussong, D.; Mouginis-Mark, P. J.

1984-01-01

70

Volcanoes  

NSDL National Science Digital Library

Create a poster about volcanoes Directions: Make a poster about volcanoes. (20 points) Include at least (1) large picture (15 points) on your poster complete with labels of every part (10 points). (15 points) Include at least three (3) facts about volcanoes. (5 points each) (15 points) Write at least a three sentence summary of your poster and volcanoes. (5 points) Use at ...

Walls, Mrs.

2011-01-30

71

Unravelling the Geometry of Unstable Flanks of Submarine Volcanoes by Magnetic Investigation: the Case of the "sciara del Fuoco" Scar (stromboli Volcano, Aeolian Islands)  

NASA Astrophysics Data System (ADS)

Stromboli is the easternmost island of the Aeolian Archipelago (Tyrrhenian Sea) and one of the most active Mediterranean volcanoes. The volcanic edifice rises over 3000 m above the surrounding seafloor, from a depth of about 2000 m b.s.l. to 924 m a.s.l. The north-western flank of volcano is deeply scarred by a destructive collapse event occurred ca. 5000 years ago, and forming a big horseshoe-shaped depression, known as "Sciara del Fuoco" (SdF). This depression, 3 Km long and 2 Km wide, is supposed to extend into the sea down to 700 m b.s.l., while further basinward it turns into a fan-shaped mounted deposit down to about 2600 m b.s.l., where it merges the so-called "Stromboli Canyon". Since its formation, emerged and submerged portions of the SdF have been progressively filled by the volcanic products of the persistent activity of the Stromboli Volcano. In the last 10 years, two paroxysmal eruptions occurred in the Stromboli Volcano, during 2002-2003 and February-April 2007. During both events, the SdF has been partially covered by lava flows and affected by slope failures, also causing (for the 2002-2003 event) a local tsunami. Since the 1990's, and especially after the last two paroxysms, the submerged extension of the SdF has been intensively investigated by using swath bathymetry data. We focused principally on the magnetic anomaly pattern of the submerged SdF since the chaotic depositional system virtually cancels magnetic remanence (which at Stromboli can reach 5-10 A/m values), thus lowering magnetic residual intensity. On July 2012 we acquired new detailed sea-surface magnetic data of the SdF from the shoreline to about 7 km offshore, where the depth is more than 1800 m b.s.l. We collected data thanks to the Italian Navy ship "Nave Aretusa" and by using the Marine Magnetics SeaSPY magnetometer. At the same time, new bathymetric data were acquired in the same area by using a Kongsberg Marine multibeam systems. Although the morphologic features of the submarine prosecution of the SdF system were already studied and unveiled, the complete description of the in-depth extension of the system and the overall volume estimation is still poorly known. This has important implications for the hazard assessment of the landslide structure and most generally of the entire volcanic edifice. The application of a classical geomagnetic prospection to describe a landslide feature is an uncommon procedure yet it can be considered as innovative approach, having the advantages of effectiveness, low cost and expedition typical of the geomagnetic survey. Here we present the interpretation of the newly acquired high-resolution magnetic dataset, thanks to susceptibility and magnetic remanence values gathered from on-land rock samples at Stromboli. A 3D inverse model is here proposed, allowing a full definition of the submerged SdF structure geometry.

Muccini, F.; Cocchi, L.; Carmisciano, C.; Speranza, F.; Marziani, F.

2012-12-01

72

Dive and Explore: An Interactive Exhibit That Simulates Making an ROV Dive to a Submarine Volcano, Hatfield Marine Science Visitor Center, Newport, Oregon  

NASA Astrophysics Data System (ADS)

We have created a new interactive exhibit in which the user can sit down and simulate that they are making a dive to the seafloor with the remotely operated vehicle (ROV) named ROPOS. The exhibit immerses the user in an interactive experience that is naturally fun but also educational. This new public display is located at the Hatfield Marine Science Visitor Center in Newport, Oregon. The exhibit is designed to look like the real ROPOS control console and includes three video monitors, a PC, a DVD player, an overhead speaker, graphic panels, buttons, lights, dials, and a seat in front of a joystick. The dives are based on real seafloor settings at Axial seamount, an active submarine volcano on the Juan de Fuca Ridge (NE Pacific) that is also the location of a seafloor observatory called NeMO. The user can choose between 1 of 3 different dives sites in the caldera of Axial Volcano. Once a dive is chosen, then the user watches ROPOS being deployed and then arrives into a 3-D computer-generated seafloor environment that is based on the real world but is easier to visualize and navigate. Once on the bottom, the user is placed within a 360 degree panorama and can look in all directions by manipulating the joystick. By clicking on markers embedded in the scene, the user can then either move to other panorama locations via movies that travel through the 3-D virtual environment, or they can play video clips from actual ROPOS dives specifically related to that scene. Audio accompanying the video clips informs the user where they are going or what they are looking at. After the user is finished exploring the dive site they end the dive by leaving the bottom and watching the ROV being recovered onto the ship at the surface. The user can then choose a different dive or make the same dive again. Within the three simulated dives there are a total of 6 arrival and departure movies, 7 seafloor panoramas, 12 travel movies, and 23 ROPOS video clips. The exhibit software was created with Macromedia Director using Apple Quicktime and Quicktime VR. The exhibit is based on the NeMO Explorer web site (http://www.pmel.noaa.gov/vents/nemo/explorer.html).

Weiland, C.; Chadwick, W. W.; Hanshumaker, W.; Osis, V.; Hamilton, C.

2002-12-01

73

Magma Ascent to Submarine Volcanoes: Real-Time Monitoring by Means of Teleseismic Observations of Earthquake Swarms  

NASA Astrophysics Data System (ADS)

Earthquake swarm occurrence belongs to reliable indicators of magmatic activity in the Earth crust. Their occurrence beneath submarine portions of volcanic arcs brings valuable information on plumbing systems of this unsufficiently understood environment and reveals recently active submarine volcanoes. Utilisation of teleseismically recorded data (NEIC, GCMT Project) enables to observe magmatic activity in almost real time. We analysed seismicity pattern in two areas - the Andaman-Nicobar region in April 2012 and the southern Ryukyu in April 2013. In both regions, the swarms are situated 80-100 km above the Wadati-Benioff zone of the subducting slab. Foci of the swarm earthquakes delimit a seismogenic layer at depths between 9 - 35 km that should be formed by brittle and fractured rock environment. Repeated occurrence of earthquakes clustered in swarms excludes large accumulations of melted rocks in this layer. Magma reservoirs should be situated at depths greater than 35 km. Upward magma migration from deeper magma reservoirs to shallow magma chambers or to the seafloor induce earthquake swarms by increasing tectonic stress and/or decreasing friction at faults. Frequency of earthquake swarm occurrence in the investigated areas has made a volcanic eruption at the seafloor probable. Moreover, epicentral zones of the swarms often coincide with distinct elevations at the seafloor - seamounts and seamount ranges. High accuracy of global seismological data enabled also to observe migration of earthquakes during individual swarms (Fig. 1), probably reflecting dike and/or sill propagation. Triggering of earthquake swarms by distant strong earthquakes was repeatedly observed in the Andaman-Nicobar region. The presented study documents high accuracy of hypocentral determinations published by the above mentioned data centers and usefulness of the EHB relocation procedure. Epicentral map of the October 2002 earthquake swarm in southern Ryukyu showing E-W migration of events during the swarm. The swarm occurred during 29 hours on October 23 - 25 in the magnitude range 4.0 - 5.2. Open circles - epicenters of all 54 events of the swarm; red circles - epicenters of events that occurred in a particular time interval of the swarm development: (a) - starting 3 hours; (b) - following 4 hours; (c) - final 22 hours.

Spicak, A.; Vanek, J.; Kuna, V. M.

2013-12-01

74

Vailulu'u Seamount, Samoa: Life and Death at the Edge of An Active Submarine Volcano  

NASA Astrophysics Data System (ADS)

Exploration of Vailulu'u seamount (14°13'S; 169°04'W) by manned submersible, ROV, and surface ship revealed a new, 300m tall volcano that has grown in the summit crater in less than four years. This shows that Vailulu'u's eruption behavior is at this stage not predictable and continued growth could allow Vailulu'u to breach sea level within decades Several types of hydrothermal vents fill Vailulu'u crater with particulates that reduce visibility to less than a few meters in some regions. Hydrothermal solutions mix with seawater that enters the crater from its breaches to produce distinct biological habitats. Low temperature hydrothermal vents can produce Fe-oxide chimneys or up to one meter-thick microbial mats. Higher temperature vents (85°C) produce low salinity acidic fluids containing buoyant droplets of immiscible CO2. Low temperature hydrothermal vents at Nafanua summit (708m depth) support a thriving population of eels (Dysommia rusosa). The areas around the high temperature vents and the moat and remaining crater around the new volcano is almost devoid of any macroscopic life and is littered with fish, and mollusk carcasses that apparently died from exposure to hydrothermal fluid components in deeper crater waters. Acid- tolerant polychaetes adapt to this environment and feed near and on these carcasses. Vailulu'u presents a natural laboratory for the study of how seamounts and their volcanic systems interact with the hydrosphere to produce distinct biological habitats, and how marine life can adapt to these conditions or be trapped in a toxic volcanic system that leads to mass mortality. The Vailulu'u research team: Hubert Staudigel, Samantha Allen, Brad Bailey, Ed Baker, Sandra Brooke, Ryan Delaney, Blake English, Lisa Haucke, Stan Hart, John Helly, Ian Hudson, Matt Jackson, Daniel Jones, Alison Koleszar, Anthony Koppers, Jasper Konter, Laurent Montesi, Adele Pile, Ray Lee, Scott Mcbride, Julie Rumrill, Daniel Staudigel, Brad Tebo, Alexis Templeton, Rhea Workman, Craig Young, Robert Zierenberg.

Vailulu'U Research Group, T.

2005-12-01

75

Volcanoes  

SciTech Connect

This book describes volcanoes although the authors say they are more to be experienced than described. This book poses more question than answers. The public has developed interest and awareness in volcanism since the first edition eight years ago, maybe because since the time 120 volcanoes have erupted. Of those, the more lethal eruptions were from volcanoes not included in the first edition's World's 101 Most Notorious Volcanoes.

Decker, R.W.; Decker, B.

1989-01-01

76

The volcanic debris avalanche on the SE submarine slope of Nisyros volcano, Greece: geophysical exploration and implications for subaerial eruption history  

NASA Astrophysics Data System (ADS)

A spectacular hummocky topography was discovered offshore of the south-eastern slope of the Nisyros island volcano in the eastern sector of the Aegean volcanic arc in 2000-2001, using multibeam bathymetric mapping and seismic profiling, and interpreted as part of a volcanic debris avalanche originating onland. During E/V Nautilus cruise NA011 in 2010, a detailed side-scan sonar and ROV exploration aimed at evaluating the surface morphology of this avalanche field. Combining the new data with selected older datasets reveals that the debris avalanche is characterized by numerous (at least 78) variously sized and shaped hummocks. Some of these are distinctly round, either scattered or aligned in groups, whereas others are elongated in the form of ridges. This is consistent with existing models accounting for variations in the longitudinal and lateral velocity ratio of landslides. Maximum dimensions reach 60 m in height above the sea bottom, 220 m in length and 230 m in width. The structures outline a large tongue-shaped, submarine hummock field of about 22.2 km2, approx. 4.8 km wide and 4.6 km long and with an estimated volume of 0.277 km3. Due to its characteristic shape, the collapsed volcanic flank is interpreted to represent a singular failing event, involving a rapid and virtually instantaneous downslope movement of the slide mass into the sea. Indeed, the H/L (height of 280 m vs. run-out of 7 km) ratio for the Nisyros slide is 0.04; plotted against volume, this falls within the theoretical bounds as well as measured values typical of submarine landslides. The timing of the event is probably related to the extrusion of Nikia lavas and their subsequent failure and formation of a main scarp observed at about 120 m depth on an 8-km-long seismic profile and a map of slope angle distribution, at the depth where the palaeo-coastline was located 40 ka ago. An inferred age of ca. 40 ka for the avalanche awaits confirmation based on dating of core material.

Livanos, Isidoros; Nomikou, Paraskevi; Papanikolaou, Dimitris; Rousakis, Grigoris

2013-12-01

77

Volcanoes  

NSDL National Science Digital Library

In this lesson, students investigate the processes that build volcanoes, the types of rocks they create, the factors that influence different eruption types, and the threats volcanoes pose to their surrounding environments. They will also create a notebook of volcano characteristics and use what they have learned to identify physical features and eruption types in some real-life documented volcanic episodes.

2005-01-01

78

Survival of mussels in extremely acidic waters on a submarine volcano  

NASA Astrophysics Data System (ADS)

Increasing atmospheric carbon dioxide levels are causing ocean acidification, compromising the ability of some marine organisms to build and maintain support structures as the equilibrium state of inorganic carbon moves away from calcium carbonate. Few marine organisms tolerate conditions where ocean pH falls significantly below today's value of about 8.1 and aragonite and calcite saturation values below 1 (refs 5, 6). Here we report dense clusters of the vent mussel Bathymodiolus brevior in natural conditions of pH values between 5.36 and 7.29 on northwest Eifuku volcano, Mariana arc, where liquid carbon dioxide and hydrogen sulphide emerge in a hydrothermal setting. We find that both shell thickness and daily growth increments in shells from northwest Eifuku are only about half those recorded from mussels living in water with pH>7.8. Low pH may therefore also be implicated in metabolic impairment. We identify four-decade-old mussels, but suggest that the mussels can survive for so long only if their protective shell covering remains intact: crabs that could expose the underlying calcium carbonate to dissolution are absent from this setting. The mussels' ability to precipitate shells in such low-pH conditions is remarkable. Nevertheless, the vulnerability of molluscs to predators is likely to increase in a future ocean with low pH.

Tunnicliffe, Verena; Davies, Kimberley T. A.; Butterfield, David A.; Embley, Robert W.; Rose, Jonathan M.; Chadwick, William W., Jr.

2009-05-01

79

The Submarine Volcano Eruption off El Hierro Island: Effects on the Scattering Migrant Biota and the Evolution of the Pelagic Communities  

PubMed Central

The submarine volcano eruption off El Hierro Island (Canary Islands) on 10 October 2011 promoted dramatic perturbation of the water column leading to changes in the distribution of pelagic fauna. To study the response of the scattering biota, we combined acoustic data with hydrographic profiles and concurrent sea surface turbidity indexes from satellite imagery. We also monitored changes in the plankton and nekton communities through the eruptive and post-eruptive phases. Decrease of oxygen, acidification, rising temperature and deposition of chemicals in shallow waters resulted in a reduction of epipelagic stocks and a disruption of diel vertical migration (nocturnal ascent) of mesopelagic organisms. Furthermore, decreased light levels at depth caused by extinction in the volcanic plume resulted in a significant shallowing of the deep acoustic scattering layer. Once the eruption ceased, the distribution and abundances of the pelagic biota returned to baseline levels. There was no evidence of a volcano-induced bloom in the plankton community.

Ariza, Alejandro; Kaartvedt, Stein; R?stad, Anders; Garijo, Juan Carlos; Aristegui, Javier; Fraile-Nuez, Eugenio; Hernandez-Leon, Santiago

2014-01-01

80

Network-based evaluation of infrasound source location at Sakurajima Volcano, Japan  

NASA Astrophysics Data System (ADS)

An important step in advancing the science and application of volcano infrasound is improved source location and characterization. Here we evaluate different network-based infrasonic source location methods, primarily srcLoc and semblance, using data collected at Sakurajima Volcano, Japan in July 2013. We investigate these methods in 2- and 3-dimensions to assess the necessity of considering 3-D sensor and vent locations. In addition, we compare source locations found using array back azimuth projection from dual arrays. The effect of significant local topography on source location will also be evaluated. Preliminary analysis indicates periods of high- and low-level activity, suggesting different processes occurring in the upper conduit and vent. Network processing will be applied to determine signal versus noise, a technique which illuminates when the volcano is producing infrasound, to further investigate these processes. We combine this with other methods to identify the number and style of eruptions. By bringing together source location, timing of activity level, type of activity (such as tremor, explosions, etc.), and number of events, we aim to improve understanding of the activity and associated infrasound signals at Sakurajima Volcano.

McKee, K. F.; Fee, D.; Rowell, C. R.; Johnson, J. B.; Yokoo, A.; Matoza, R. S.

2013-12-01

81

How Slab Dip Affects the Location of Volcanoes  

NSDL National Science Digital Library

Students will plot the locations of earthquakes on the top of subducting slabs to determine slab dip and will then develop hypotheses regarding the relationship between slab dip, the depth of the slab, and volcanic activity on the surface.

Beutel, Erin

82

Submarine hydrothermal activity and gold-rich mineralization at Brothers Volcano, Kermadec Arc, New Zealand  

NASA Astrophysics Data System (ADS)

Brothers volcano, of the Kermadec intraoceanic arc, is host to a hydrothermal system unique among seafloor hydrothermal systems known anywhere in the world. It has two distinct vent fields, known as the NW Caldera and Cone sites, whose geology, permeability, vent fluid compositions, mineralogy, and ore-forming conditions are in stark contrast to each other. The NW Caldera site strikes for ˜600 m in a SW-NE direction with chimneys occurring over a ˜145-m depth interval, between ˜1,690 and 1,545 m. At least 100 dead and active sulfide chimney spires occur in this field and are typically 2-3 m in height, with some reaching 6-7 m. Their ages (at time of sampling) fall broadly into three groups: <4, 23, and 35 years old. The chimneys typically occur near the base of individual fault-controlled benches on the caldera wall, striking in lines orthogonal to the slopes. Rarer are massive sulfide crusts 2-3 m thick. Two main types of chimney predominate: Cu-rich (up to 28.5 wt.% Cu) and, more commonly, Zn-rich (up to 43.8 wt.% Zn). Geochemical results show that Mo, Bi, Co, Se, Sn, and Au (up to 91 ppm) are correlated with the Cu mineralization, whereas Cd, Hg, Sb, Ag, and As are associated with the dominant Zn-rich mineralization. The Cone site comprises the Upper Cone site atop the summit of the recent (main) dacite cone and the Lower Cone site that straddles the summit of an older, smaller, more degraded dacite cone on the NE flank of the main cone. Huge volumes of diffuse venting are seen at the Lower Cone site, in contrast to venting at both the Upper Cone and NW Caldera sites. Individual vents are marked by low-relief (?0.5 m) mounds comprising predominately native sulfur with bacterial mats. Vent fluids of the NW Caldera field are focused, hot (?300°C), acidic (pH ? 2.8), metal-rich, and gas-poor. Calculated end-member fluids from NW Caldera vents indicate that phase separation has occurred, with Cl values ranging from 93% to 137% of seawater values. By contrast, vent fluids at the Cone site are diffuse, noticeably cooler (?122°C), more acidic (pH 1.9), metal-poor, and gas-rich. Higher-than-seawater values of SO4 and Mg in the Cone vent fluids show that these ions are being added to the hydrothermal fluid and are not being depleted via normal water/rock interactions. Iron oxide crusts 3 years in age cover the main cone summit and appear to have formed from Fe-rich brines. Evidence for magmatic contributions to the hydrothermal system at Brothers includes: high concentrations of dissolved CO2 (e.g., 206 mM/kg at the Cone site); high CO2/3He; negative ?D and ?18OH2O for vent fluids; negative ?34S for sulfides (to -4.6‰), sulfur (to -10.2‰), and ?15N2 (to -3.5‰); vent fluid pH values to 1.9; and mineral assemblages common to high-sulfidation systems. Changing physicochemical conditions at the Brothers hydrothermal system, and especially the Cone site, occur over periods of months to hundreds of years, as shown by interlayered Cu + Au- and Zn-rich zones in chimneys, variable fluid and isotopic compositions, similar shifts in 3He/4He values for both Cone and NW Caldera sites, and overprinting of "magmatic" mineral assemblages by water/rock-dominated assemblages. Metals, especially Cu and possibly Au, may be entering the hydrothermal system via the dissolution of metal-rich glasses. They are then transported rapidly up into the system via magmatic volatiles utilizing vertical (˜2.5 km long), narrow (˜300-m diameter) "pipes," consistent with evidence of vent fluids forming at relatively shallow depths. The NW Caldera and Cone sites are considered to represent stages along a continuum between water/rock- and magmatic/hydrothermal-dominated end-members.

de Ronde, Cornel E. J.; Massoth, Gary J.; Butterfield, David A.; Christenson, Bruce W.; Ishibashi, Junichiro; Ditchburn, Robert G.; Hannington, Mark D.; Brathwaite, Robert L.; Lupton, John E.; Kamenetsky, Vadim S.; Graham, Ian J.; Zellmer, Georg F.; Dziak, Robert P.; Embley, Robert W.; Dekov, Vesselin M.; Munnik, Frank; Lahr, Janine; Evans, Leigh J.; Takai, Ken

2011-07-01

83

Geochemistry of Fresh Submarine HSDP-2 Glasses from Mauna Kea Volcano: Unexpected Mobility of 'Immobile' Trace Elements  

NASA Astrophysics Data System (ADS)

The Hawaii Scientific Drilling Project-2 provides the opportunity to investigate the geochemical evolution of the submarine section of Mauna Kea. Our previous analyses of bulk-rock trace element concentrations had revealed relatively high degrees of scatter of trace element ratios such as Th/U, Ta/U and even Nb/Ta, and we suspected that many of the samples had been affected by seawater alteration. Fortunately, fresh glasses are found throughout the drill core in many glass-rich hyaloclastic and pillow basalts with glass proportions up to 10%. We therefore determined incompatible trace elements such as Th, U, Nb, Ta, Zr, Ba, Pb, Rb in carefully handpicked, fresh glasses in 16 samples derived from depths between 1310 m and 3050 m. The samples were crushed to less than 0.425 mm grain size in order to obtain very fresh glass fragments free of contamination by alteration products, olivines or other minerals. The glass fractions and their corresponding bulk samples were analyzed for major and trace elements by EMP, MIC-SSMS and HR-ICPMS. The differences between glass and bulk are particularly obvious in Pb, Rb, Cs and U. As expected, Pb, Rb and Cs were found to be mobile, with concentrations in the bulk samples varying by up to a factor of 5 relative to the glass samples. Similarly, U concentrations in glass are up to a factor of 2 higher than in bulk samples. More surprising is the observation that Th and Ta are quite probably mobile, because these elements are normally believed to be immobile. However, these results are consistent with those of Bienvenue et al. (1990), who found that Th appears to be sensitive to seawater alteration. Our glass data indicate that Ta/U (3.7+/-0.2) is uniform along the sequence, in contrast to the bulk data which show a large scatter (3.7-6.5). Th/U ratios in the glasses show a maximum (~3.5) at a depth of ~2100 m, whereas low ratios of about 3 were found in depths of 1300-1400 m and 2800-3000 m. The high Th/U ratios in the 2100 m region are associated with low SiO2 contents, high 208Pb*/206Pb*(Eisele et al., 2002; Blichert-Toft et al., 2002) and high 3He/4He ratios (Kurz, personal comm., Althaus et al., 2002). Thus, it appears that the high Th/U values are not caused by melting effects but are features of an anomalous source chemistry sampled by the volcano at this stratigraphic level.

Amini, M. A.; Jochum, K. P.; Stoll, B.; Willbold, M.; Sobolev, A. V.; Hofmann, A. W.

2002-12-01

84

An experiment to detect and locate lightning associated with eruptions of Redoubt Volcano  

USGS Publications Warehouse

A commercially-available lightning-detection system was temporarily deployed near Cook Inlet, Alaska in an attempt to remotely monitor volcanogenic lightning associated with eruptions of Redoubt Volcano. The system became operational on February 14, 1990; lightning was detected in 11 and located in 9 of the 13 subsequent eruptions. The lightning was generated by ash clouds rising from pyroclastic density currents produced by collapse of a lava dome emplaced near Redoubt's summit. Lightning discharge (flash) location was controlled by topography, which channeled the density currents, and by wind direction. In individual eruptions, early flashes tended to have a negative polarity (negative charge is lowered to ground) while late flashes tended to have a positive polarity (positive charge is lowered to ground), perhaps because the charge-separation process caused coarse, rapid-settling particles to be negatively charged and fine, slow-settling particles to be positively charged. Results indicate that lightning detection and location is a useful adjunct to seismic volcano monitoring, particularly when poor weather or darkness prevents visual observation. The simultaneity of seismicity and lightning near a volcano provides the virtual certainty that an ash cloud is present. This information is crucial for aircraft safety and to warn threatened communities of impending tephra falls. The Alaska Volcano Observatory has now deployed a permanent lightning-detection network around Cook Inlet. ?? 1994.

Hoblitt, R. P.

1994-01-01

85

The beginning of explosive eruptions on a location lacking volcanoes: A case study on the Hijiori volcano, Northeastern Japan  

Microsoft Academic Search

The volcanic activity of Hijiori volcano (N38 36°f 35°f°f, E140 9°f 20°f°f, WGS84) is reported in detail as a case study to understand how a new felsic volcano commences the activity. Hijiori volcano, a small caldera with approximately 2 km in diameter, is one of the 108 active volcanoes in Japan, which erupted at about 12,000 years ago (in Calendar

I. Miyagi

2006-01-01

86

Volcanoes  

USGS Publications Warehouse

Volcanoes destroy and volcanoes create. The catastrophic eruption of Mount St. Helens on May 18, 1980, made clear the awesome destructive power of a volcano. Yet, over a time span longer than human memory and record, volcanoes have played a key role in forming and modifying the planet upon which we live. More than 80 percent of the Earth's surface--above and below sea level--is of volcanic origin. Gaseous emissions from volcanic vents over hundreds of millions of years formed the Earth's earliest oceans and atmosphere, which supplied the ingredients vital to evolve and sustain life. Over geologic eons, countless volcanic eruptions have produced mountains, plateaus, and plains, which subsequent erosion and weathering have sculpted into majestic landscapes and formed fertile soils.

Tilling, Robert I.

1998-01-01

87

Volcanoes  

NSDL National Science Digital Library

This resource provides general information about volcanoes. It illustrates the growth of a volcano, using Paricutin and Mt. St. Helens as examples of an active volcano and a lava dome. The terms extinct and dormant are also discussed. This site provides an explanation of why and how volcanoes form, zones of subduction, mid-ocean ridges, and hot spots. Deadly dangers associated with eruptions are discussed as is the use of a tiltmeter for prediction. The content center lesson describes a possible connection between the lost continent of Atlantis and the island of Santorini. Dissolved gasses in magma and the creation of a lava dome are both demonstrated in the hands-on section.

Johnson, Scott

88

Location Analysis and Assessment of Submarine Groundwater Discharge: A Geospatial Approach  

NASA Astrophysics Data System (ADS)

Coastal aquifers have the tendency to discharge their subsurface flow into the sea either through seepage or submarine springs where fractures prevail, having some hydraulic links with the sea resulting in dominant flow of submarine springs. The existence of these springs was known for more than last 1000 years since the time of the Phoenicians where they used to use submarine springs for mainly drinking purposes. Submarine Groundwater Discharges (SGDs) are receiving considerable attention in the literature as a major pathway for anthropogenically derived pollutants to coastal waters in recent days. The specific objective of this research is to develop remote sensing as a tool for the identification, quantification and mapping of SGDs. The principal means of the assessment will be using optical and thermal infrared remote sensing techniques. Identification of the geologic and anthropogenic controls on SGDs through an analysis of available offshore and onshore geological spatial datasets and available satellite imagery within a GIS framework is the main goal of this research work which will help to determine the significance of SGDs to the nutrient load on the coastal and estuarine ecosystem.

Mukherjee, Subham

2013-04-01

89

Preliminary results from Submarine Ring of Fire 2012 - NE Lau: First explorations of hydrothermally active volcanoes across the supra-subduction zone and a return to the West Mata eruption site  

NASA Astrophysics Data System (ADS)

Several expeditions in the past few years have shown that the NE Lau basin has one of the densest concentrations of volcanically and hydrothermally active volcanoes on the planet. In 2008 two active submarine volcanic eruptions were discovered during a one week period and subsequent dives with the Jason remotely operated vehicle at one of the sites (West Mata) revealed an active boninite eruption taking place at 1200 m depth. Two dives at the other revealed evidence for recent eruption along the NE Lau Spreading Center. Several more expeditions in 2010-11 discovered additional evidence about the extent and types of hydrothermal activity in this area. Data from CTDO (conductivity, temperature, depth, optical) vertical casts, tow-yos, and towed camera deployments revealed more than 15 hydrothermal sites at water depths from ~800 to 2700 m that include sites from the magmatic arc, the "rear arc," and the back arc spreading centers. These sites range from high temperature black smoker sulfide-producing systems to those dominated by magmatic degassing. Dives by remotely operated vehicle (Quest 4000) in September 2012 will explore these sites and return samples for chemical, biological and geologic studies. One of the dives will be a return visit to West Mata volcano, the site of the deepest submarine eruption yet observed (in 2009). Recent multibeam data reveal large changes in West Mata's summit, suggesting that the nature of the eruption and the location of the erupting vents may have changed. In addition to the preliminary results from the science team, we will also discuss our use and experience with continuous live video transmission (through the High Definition video camera on the Quest 4000) back to shore via satellite and through the internet. Submarine Ring of Fire 2012 Science Team: Bradley Tebo, Bill Chadwick, Ed Baker, Ken Rubin, Susan Merle, Timothy Shank, Sharon Walker, Andra Bobbitt, Nathan Buck, David Butterfield, Eric Olson, John Lupton, Richard Arculus, Fabio Caratori-Tontini, Rick Davis, Kevin Roe, Edward Mitchell, Paula Keener-Chavis Carolyn Sheehan, Peter Crowhurst, Simon Richards,and Volker Ratmeyer along with the Quest-4000 team. .

Resing, J.; Embley, R. W.

2012-12-01

90

Locating sources of volcanic explosions and study of the structure at Yasur volcano, Vanuatu  

NASA Astrophysics Data System (ADS)

Yasur volcano is a small scoria cone, located on Tanna Island, in southern Vanuatu. The cone is composed of 3 vents: two vents (A and B) in the southern crater and one vent (C) in the northern crater. The volcano is going through a permanent strombolian activity, characterized by explosions of gas bubbles and small ash plumes. The activity generates thousands of seismic signals per day, mostly explosion quakes and LP events. From January 2008 to February 2009, seismic activity has been recorded by 12 seismic antennas each composed of 7 short-period sensors: a 3 components seismometer surrounded by six vertical sensors. Distances between the central seismometer and the others sensors was 20m or 40m. In May 2008, 10 broadband stations have been installed to complete the seismic network. In this work, we present both source locations and a structural study of the volcano. To locate sources of seismic events, a seismic antenna technique is used. For each signal, the slowness vectors (which contain back-azimuth and apparent slowness) are estimated on a sliding window by inversion of the time delays calculated between the sensors using the cross-spectral method. Combining back-azimuth calculated for each antenna, sources are located by using a probabilistic approach. This method enabled to locate events belonging to several families of similar explosion quakes allowing to assign each family to the activity of one of the vents. The results show periods during which the activity shifts from northern to southern part of the crater. To improve our knowledge of the volcanic structure and therefore allow the use of other location techniques such as moment-tensor inversion, we applied remote sensing techniques and array methods in order to determine a 3D seismic velocity model of the volcano. First a Digital Elevation Model with a 5 to 10 meters resolution was built from a stereoscopic couple of satellite images (with 2.5 meters resolution) georeferenced with GPS points measured during the experiment. Then velocity models have been estimated below each antenna and for the whole array. Two methods have been used for this purpose: SPatial AutoCorrelation (SPAC) and high-resolution frequency wavenumber. These techniques enabled to determine the velocity structures below each antenna down 200m below the surface. To complete these models, the same methods are used on data recorded by the broadband stations, which allowed to estimate seismic velocities for greater depths. The different velocity models and the DEM are finally combined to recompose the P and S waves 3D velocity structures at the scale of the volcano.

Perrier, Laurence; Métaxian, Jean-Philippe; Battaglia, Jean; Garaebiti, Esline

2010-05-01

91

Volcanoes  

NSDL National Science Digital Library

This module include four problem-based learning scenarios related to volcanoes and emphasize different kinds of volcanic hazards and geologic processes. The four scenarios are: whether to build a new high school in the shadow of a restless volcanic giant, Mt. Rainier; Kilauea in Hawaii shows signs of activity. What are the prospects for the nearby population?; Mt. Hood is starting to act like Mt. St. Helens did in 1980, but Mt. Hood is just 40 miles from the metropalitan area. How might an eruption impact this populated area?; and America's largest volcano in Yellowstone National Park is stirring. Are we facing an eruption as devastating as a nuclear attack? This module is from Exploring the Environment.

92

The NeMO Explorer Web Site: Interactive Exploration of a Recent Submarine Eruption and Hydrothermal Vents, Axial Volcano, Juan de Fuca Ridge  

NASA Astrophysics Data System (ADS)

To help visualize the submarine volcanic landscape at NOAA's New Millennium Observatory (NeMO), we have created the NeMO Explorer web site: http://www.pmel.noaa.gov/vents/nemo/explorer.html. This web site takes visitors a mile down beneath the ocean surface to explore Axial Seamount, an active submarine volcano 300 miles off the Oregon coast. We use virtual reality to put visitors in a photorealistic 3-D model of the seafloor that lets them view hydrothermal vents and fresh lava flows as if they were really on the seafloor. At each of six virtual sites there is an animated tour and a 360o panorama in which users can view the volcanic landscape and see biological communities within a spatially accurate context. From the six sites there are hyperlinks to 50 video clips taken by a remotely operated vehicle. Each virtual site concentrates on a different topic, including the dynamics of the 1998 eruption at Axial volcano (Rumbleometer), high-temperature hydrothermal vents (CASM and ASHES), diffuse hydrothermal venting (Marker33), subsurface microbial blooms (The Pit), and the boundary between old and new lavas (Castle vent). In addition to exploring the region geographically, visitors can also explore the web site via geological concepts. The concepts gallery lets you quickly find information about mid-ocean ridges, hydrothermal vents, vent fauna, lava morphology, and more. Of particular interest is an animation of the January 1998 eruption, which shows the rapid inflation (by over 3 m) and draining of the sheet flow. For more info see Fox et al., Nature, v.412, p.727, 2001. This project was funded by NOAA's High Performance Computing and Communication (HPCC) and Vents Programs. Our goal is to present a representative portion of the vast collection of NOAA's multimedia imagery to the public in a way that is easy to use and understand. These data are particularly challenging to present because of their high data rates and low contextual information. The 3-D models create effective context and new video technology allows us to present good quality video at lower data rates. Related curriculum materials for middle- and high-school students are also available from the NeMO web site at http://www.pmel.noaa.gov/vents/nemo/education.html. >http://www.pmel.noaa.gov/vents/nemo/explorer.html

Weiland, C.; Chadwick, W. W.; Embley, R. W.

2001-12-01

93

Methane discharge from a deep-sea submarine mud volcano into the upper water column by gas hydrate-coated methane bubbles  

NASA Astrophysics Data System (ADS)

The assessment of climate change factors includes a constraint of methane sources and sinks. Although marine geological sources are recognized as significant, unfortunately, most submarine sources remain poorly quantified. Beside cold vents and coastal anoxic sediments, the large number of submarine mud volcanoes (SMV) may contribute significantly to the oceanic methane pool. Recent research suggests that methane primarily released diffusively from deep-sea SMVs is immediately oxidized and, thus, has little climatic impact. New hydro-acoustic, visual, and geochemical observations performed at the deep-sea mud volcano Håkon Mosby reveal the discharge of gas hydrate-coated methane bubbles and gas hydrate flakes forming huge methane plumes extending from the seabed in 1250 m depth up to 750 m high into the water column. This depth coincides with the upper limit of the temperature-pressure field of gas hydrate stability. Hydrographic evidence suggests bubble-induced upwelling within the plume and extending above the hydrate stability zone. Thus, we propose that a significant portion of the methane from discharged methane bubbles can reach the upper water column, which may be explained due to the formation of hydrate skins. As the water mass of the plume rises to shallow water depths, methane dissolved from hydrated bubbles may be transported towards the surface and released to the atmosphere. Repeated acoustic surveys performed in 2002 and 2003 suggest continuous methane emission to the ocean. From seafloor visual observations we estimated a gas flux of 0.2 (0.08-0.36) mol s -1 which translates to several hundred tons yr -1 under the assumption of a steady discharge. Besides, methane was observed to be released by diffusion from sediments as well as by focused outflow of methane-rich water. In contrast to the bubble discharge, emission rates of these two pathways are estimated to be in the range of several tons yr -1 and, thus, to be of minor importance. Very low water column methane oxidation rates derived from incubation experiments with tritiated methane suggest that methane is distributed by currents rather than oxidized rapidly.

Sauter, Eberhard J.; Muyakshin, Sergey I.; Charlou, Jean-Luc; Schlüter, Michael; Boetius, Antje; Jerosch, Kerstin; Damm, Ellen; Foucher, Jean-Paul; Klages, Michael

2006-03-01

94

Volcanic Risk Perception in Five Communities Located near the Chichón Volcano, Northern Chiapas, Mexico  

NASA Astrophysics Data System (ADS)

The Chichón volcano (17° 19’ N and 93° 15’ W) is located in the state of Chiapas, Mexico. This volcano is classified by UNESCO as one of the ten most dangerous volcanos in the world. The eruptions of March and April in 1982 affected at least 51 communities located in the surroundings of the volcano and caused the death of about 2000 people. In this work we evaluate the risk perception in five communities highly populated: Juárez, Ostuacán, Pichucalco, Reforma and Sunuapa. We selected these communities because they have a high possibility to be affected by a volcanic eruption in the future. Our survey was carried out during February and March 2006. A total of 222 families were interviewed using a questionnaire to measure risk perception. These questionnaires retrieved general information as how long people had been living there and their reasons to do so; their experiences during the 1982 events, their opinion about the authorities participation and their perception of volcanic risk; the plans of the community for disaster prevention and mitigation. Some of the most important results are: (1). People perceive a very low volcanic risk and the 70% of interviewees believe that a new eruption in the future is almost improbable because it happened in 1982. This result is particularly interesting because, according to the state government, more than 100,000 inhabitants will be directly affected in case of a new similar eruption; (2). About 95% of the population do not know the current activity of the volcano and consider that the authorities do not inform properly to their communities; (3). The response of the authorities during the events of 1982 was ranked as deficient mainly because they were unable provide shelters, storage facilities, food as well as medicine and health care access; (4). Approximately 60% of the community will accept to be re-located again in case of a new eruption; (5). About 70% of the population will not accept to be re-located because they do not know any plan, strategy, emergency schemes or shelters locations no even evacuation routes. In conclusion, during the 1982 eruption the risk perception of the population played an important role in the social impact on the region. We believe that if the population had had a proper perception of their volcanic risk, the number of casualties would have been lower. Thus, the present low volcanic risk perception of the five studied communities can be considered as an important element of vulnerability. Frances Rodríguez-VanGort1 and David A. Novelo-Casanova2 (1) Posgrado Instituto de Geofísica, Universidad Nacional Autónoma de México, Ciudad Universitaria, México Distrito Federal (2) Departamento de Sismología Instituto de Geofísica, Universidad Nacional Autónoma de México, Ciudad Universitaria, México Distrito Federal

Rodriguez, F.; Novelo-Casanova, D. A.

2010-12-01

95

Kinematic variables and water transport control the formation and location of arc volcanoes.  

PubMed

The processes that give rise to arc magmas at convergent plate margins have long been a subject of scientific research and debate. A consensus has developed that the mantle wedge overlying the subducting slab and fluids and/or melts from the subducting slab itself are involved in the melting process. However, the role of kinematic variables such as slab dip and convergence rate in the formation of arc magmas is still unclear. The depth to the top of the subducting slab beneath volcanic arcs, usually approximately 110 +/- 20 km, was previously thought to be constant among arcs. Recent studies revealed that the depth of intermediate-depth earthquakes underneath volcanic arcs, presumably marking the slab-wedge interface, varies systematically between approximately 60 and 173 km and correlates with slab dip and convergence rate. Water-rich magmas (over 4-6 wt% H(2)O) are found in subduction zones with very different subduction parameters, including those with a shallow-dipping slab (north Japan), or steeply dipping slab (Marianas). Here we propose a simple model to address how kinematic parameters of plate subduction relate to the location of mantle melting at subduction zones. We demonstrate that the location of arc volcanoes is controlled by a combination of conditions: melting in the wedge is induced at the overlap of regions in the wedge that are hotter than the melting curve (solidus) of vapour-saturated peridotite and regions where hydrous minerals both in the wedge and in the subducting slab break down. These two limits for melt generation, when combined with the kinematic parameters of slab dip and convergence rate, provide independent constraints on the thermal structure of the wedge and accurately predict the location of mantle wedge melting and the position of arc volcanoes. PMID:19494913

Grove, T L; Till, C B; Lev, E; Chatterjee, N; Médard, E

2009-06-01

96

Automated identification, location, and volume estimation of rockfalls at Piton de la Fournaise volcano  

NASA Astrophysics Data System (ADS)

Since the collapse of the Dolomieu crater floor at Piton de la Fournaise Volcano (la Réunion) in 2007, hundreds of seismic signals generated by rockfalls have been recorded daily at the Observatoire Volcanologique du Piton de la Fournaise (OVPF). To study rockfall activity over a long period of time, automated methods are required to process the available continuous seismic records. We present a set of automated methods designed to identify, locate, and estimate the volume of rockfalls from their seismic signals. The method used to automatically discriminate seismic signals generated by rockfalls from other common events recorded at OVPF is based on fuzzy sets and has a success rate of 92%. A kurtosis-based automated picking method makes it possible to precisely pick the onset time and the final time of the rockfall-generated seismic signals. We present methods to determine rockfall locations based on these accurate pickings and a surface-wave propagation model computed for each station using a Fast Marching Method. These methods have successfully located directly observed rockfalls with an accuracy of about 100 m. They also make it possible to compute the seismic energy generated by rockfalls, which is then used to retrieve their volume. The methods developed were applied to a data set of 12,422 rockfalls that occurred over a period extending from the collapse of the Dolomieu crater floor in April 2007 to the end of the UnderVolc project in May 2011 to identify the most hazardous areas of the Piton de la Fournaise volcano summit.

Hibert, C.; Mangeney, A.; Grandjean, G.; Baillard, C.; Rivet, D.; Shapiro, N. M.; Satriano, C.; Maggi, A.; Boissier, P.; Ferrazzini, V.; Crawford, W.

2014-05-01

97

Bayesian statistics applied to the location of the source of explosions at Stromboli Volcano, Italy  

USGS Publications Warehouse

We present a method for determining the location and spatial extent of the source of explosions at Stromboli Volcano, Italy, based on a Bayesian inversion of the slowness vector derived from frequency-slowness analyses of array data. The method searches for source locations that minimize the error between the expected and observed slowness vectors. For a given set of model parameters, the conditional probability density function of slowness vectors is approximated by a Gaussian distribution of expected errors. The method is tested with synthetics using a five-layer velocity model derived for the north flank of Stromboli and a smoothed velocity model derived from a power-law approximation of the layered structure. Application to data from Stromboli allows for a detailed examination of uncertainties in source location due to experimental errors and incomplete knowledge of the Earth model. Although the solutions are not constrained in the radial direction, excellent resolution is achieved in both transverse and depth directions. Under the assumption that the horizontal extent of the source does not exceed the crater dimension, the 90% confidence region in the estimate of the explosive source location corresponds to a small volume extending from a depth of about 100 m to a maximum depth of about 300 m beneath the active vents, with a maximum likelihood source region located in the 120- to 180-m-depth interval.

Saccorotti, G.; Chouet, B.; Martini, M.; Scarpa, R.

1998-01-01

98

Near-real time 3D probabilistic earthquakes locations at Mt. Etna volcano  

NASA Astrophysics Data System (ADS)

Automatic procedure for locating earthquake in quasi-real time must provide a good estimation of earthquakes location within a few seconds after the event is first detected and is strongly needed for seismic warning system. The reliability of an automatic location algorithm is in?uenced by several factors such as errors in picking seismic phases, network geometry, and velocity model uncertainties. On Mt. Etna, the seismic network is managed by INGV and the quasi-real time earthquakes locations are performed by using an automatic-picking algorithm based on short-term-average to long-term-average ratios (STA/LTA) calculated from an approximate squared envelope function of the seismogram, which furnish a list of P-wave arrival times, and the location algorithm Hypoellipse, with a 1D velocity model. The main purpose of this work is to investigate the performances of a different automatic procedure to improve the quasi-real time earthquakes locations. In fact, as the automatic data processing may be affected by outliers (wrong picks), the use of a traditional earthquake location techniques based on a least-square misfit function (L2-norm) often yield unstable and unreliable solutions. Moreover, on Mt. Etna, the 1D model is often unable to represent the complex structure of the volcano (in particular the strong lateral heterogeneities), whereas the increasing accuracy in the 3D velocity models at Mt. Etna during recent years allows their use today in routine earthquake locations. Therefore, we selected, as reference locations, all the events occurred on Mt. Etna in the last year (2011) which was automatically detected and located by means of the Hypoellipse code. By using this dataset (more than 300 events), we applied a nonlinear probabilistic earthquake location algorithm using the Equal Differential Time (EDT) likelihood function, (Font et al., 2004; Lomax, 2005) which is much more robust in the presence of outliers in the data. Successively, by using a probabilistic non linear method (NonLinLoc, Lomax, 2001) and the 3D velocity model, derived from the one developed by Patanè et al. (2006) integrated with that obtained by Chiarabba et al. (2004), we obtained the best possible constraint on the location of the focii expressed as a probability density function (PDF) for the hypocenter location in 3D space. As expected, the obtained results, compared with the reference ones, show that the NonLinLoc software (applied to a 3D velocity model) is more reliable than the Hypoellipse code (applied to layered 1D velocity models), leading to more reliable automatic locations also when outliers are present.

Barberi, G.; D'Agostino, M.; Mostaccio, A.; Patane', D.; Tuve', T.

2012-04-01

99

Active Submarine Volcanoes and Electro-Optical Sensor Networks: The Potential of Capturing and Quantifying an Entire Eruptive Sequence at Axial Seamount, Juan de Fuca Ridge  

NASA Astrophysics Data System (ADS)

The NE Pacific Regional Scale Nodes (RSN) component of the NSF Ocean Observatories Initiative is designed to provide unprecedented electrical power and bandwidth to the base and summit of Axial Seamount. The scientific community is engaged in identifying a host of existing and innovative observation and measurement techniques that utilize the high-power and bandwidth infrastructure and its real-time transmission capabilities. The cable, mooring, and sensor arrays will enable the first quantitative documentation of myriad processes leading up to, during, and following a submarine volcanic event. Currently planned RSN instrument arrays will provide important and concurrent spatial and temporal constraints on earthquake activity, melt migration, hydrothermal venting behavior and chemistry, ambient currents, microbial community structure, high-definition (HD) still images and HD video streaming from the vents, and water-column chemistry in the overlying ocean. Anticipated, but not yet funded, additions will include AUVs and gliders that continually document the spatial-temporal variations in the water column above the volcano and the distal zones. When an eruption appears imminent the frequency of sampling will be increased remotely, and the potential of repurposing the tracking capabilities of the mobile sensing platforms will be adapted to the spatial indicators of likely eruption activity. As the eruption begins mobile platforms will fully define the geometry, temperature, and chemical-microbial character of the volcanic plume as it rises into the thoroughly documented control volume above the volcano. Via the Internet the scientific community will be able to witness and direct adaptive sampling in response to changing conditions of plume formation. A major goal will be to document the eruptive volume and link the eruption duration to the volume of erupted magma. For the first time, it will be possible to begin to quantify the time-integrated output of an underwater volcanic eruption linked to the heat, chemical, and biological fluxes. In the late stages of the event, the dissipation of the "event plume" into the surrounding water column and the plume's migration patterns in the ambient regional flow will be tracked using specifically designed mobile sensor-platforms. The presence of these assets opens the potential for more immediate, coordinated, and thorough event responses than the community has previously been able to mount. Given the relative abundance of information on many variables in a verifiable and archived spatial and temporal context, and the rapidly evolving ability to conduct real-time genomic analyses, our community may be able to secure entirely novel organisms that are released into the overlying ocean only under well-characterized eruptive conditions.

Delaney, J. R.; Kelley, D. S.; Proskurowski, G.; Fundis, A. T.; Kawka, O.

2011-12-01

100

Optimizing submarine berthing with a persistence incentive  

Microsoft Academic Search

Submarine berthing plans reserve mooring locations for inbound U.S. Navy nuclear submarines prior to their port entrance. Once in port, submarines may be shifted to different berthing locations to allow them to better receive services they require or to make way for other shifted vessels. However, submarine berth shifting is expensive, labor inten- sive, and potentially hazardous. This article presents

Gerald G. Brown; Kelly J. Cormican; Siriphong Lawphongpanich; Daniel B. Widdis

1997-01-01

101

Locating Pyroclastic Flows on Soufriere Hills Volcano, Montserrat, West Indies, Using Amplitude Signals From High Dynamic Range Instruments  

NASA Astrophysics Data System (ADS)

Pyroclastic flows are located using amplitude signals from a 7-station high dynamic range seismograph array located 1.9 to 6.1 km from Soufriere Hills Volcano in Montserrat, West Indies. Locations are determined by measuring the seismograph signal amplitude for an event recorded at several stations in a moving time window analysis. For a given window, the measured amplitudes are corrected to a trial source location by removing the surface wave geometric spreading, instrument gain, and the attenuation at calculated travel-times. The trial source location is then compared to other trial locations via an iterative localized grid search where the root-mean-squared (RMS) amplitude residual is minimized. The process is repeated for subsequent time steps resulting in a best-fit event location and size through time. The method has been tested on three small events occurring on April 8, 1999, August 12, 1999 and February 25, 2001 where visual observations of pyroclastic flows coincide with good seismograph station coverage (stations > 5, azimuthal gap < 160° ). For these events, the method determined the onset located at the dome and the subsequent pyroclastic flow down the flank of the volcano. Based on the location results the three events propagated ~0.5, 1.2 and 1.3 km from the dome, and had maximum reduced displacements (DR) of 5.8, 1.8 and 4.9 cm2 and pyroclastic flow velocities of 3-7, 9-30 and 4-20 ms-1 respectively. Time-lapse video of the August 12, 1999 event shows that amplitude-based location through time closely matches the observed run-out distance and velocity. Results indicate that pyroclastic flows and rockfalls can be located using amplitude signals from high dynamic range seismograph stations yielding estimates of size, trajectory and velocity, regardless of visibility conditions on the volcano. This new method is being tested as a hazard mitigation and research tool on Montserrat.

Jolly, A. D.; Jolly, A. D.; Thompson, G.; Norton, G. E.

2001-12-01

102

Dive and Explore: An Interactive Web Visualization that Simulates Making an ROV Dive to an Active Submarine Volcano  

Microsoft Academic Search

Several years ago we created an exciting and engaging multimedia exhibit for the Hatfield Marine Science Center that lets visitors simulate making a dive to the seafloor with the remotely operated vehicle (ROV) named ROPOS. The exhibit immerses the user in an interactive experience that is naturally fun but also educational. The public display is located at the Hatfield Marine

C. Weiland; W. W. Chadwick

2004-01-01

103

Regional setting of Håkon Mosby Mud Volcano, SW Barents Sea margin  

Microsoft Academic Search

The Håkon Mosby Mud Volcano (HMMV) is a seafloor mud volcano, having a 1-km-diameter circular shape and a relief of 8–10?m.\\u000a HMMV is located within a slide scar on the Bjørnøya glacial submarine fan on the SW Barents Sea slope, and is underlain by\\u000a a >6-km-thick Cenozoic sequence. Multichannel seismic data reveal a 1- to 2-km-wide disturbed zone, which extends

B. O. Hjelstuen; O. Eldholm; J. I. Faleide; P. R. Vogt

1999-01-01

104

Repetitive Long-Period Seismicity: Source Location and Mechanism Characteristics, Villarrica Volcano, Chile  

NASA Astrophysics Data System (ADS)

Villarrica Volcano, Chile has an exposed magma free-surface, characterized by vigorous degassing ranging from small bubble bursts to Strombolian style slug bursting. Slug bursting events are characterized by both repetitive seismic and acoustic signals within the long-period (LP) band. We use the very repetitive nature of the low amplitude seismic LP signals to identify them with a matched filter on several persistent seismic stations, functional over the three year experiment duration. We stack the seismic and acoustic signals accompanying degassing to increase the signal to noise ratio, and tie signals measured 2010-2012 to produce a synthetic seismic network that recorded LP signals at a wide range of azimuths and distances from the source. Particle motions for most of the 21 stations were dominantly tangential, indicating the presence of a complex source geometry that deviated greatly from the logical axisymmetric geometry visible at the lave lake surface. We use the synthetic network to solve for the moment-tensor and location of the LP source, searching for the best source-time function using combinations of moment components, single force components, and both, for six different homogeneous half-space velocity models. Using the best source configuration and velocity model as a guide, we present forward models of reasonable geometries with geologic significance, including dikes, sills, pipes, and combination mechanisms to validate and test the sensitivity of the results of the free-inversion. Our results indicate that the current repetitive LP seismicity dominated by tangential particle motions is probably associated with relic fissure geometry from the last eruptive phase, and is caused by a conduit constriction through which large gas slugs pass (seismic emission) and subsequently burst at the surface (acoustic emission).

Richardson, J.; Waite, G. P.

2012-12-01

105

Internet Geography: Volcanoes  

NSDL National Science Digital Library

This site is part of GeoNet Internet Geography, a resource for pre-collegiate British geography students and their instructors. This page focuses on various aspects of volcanoes, including the main features of a volcano, types of volcanoes, the Ring of Fire, locations of volcanoes, volcanic flows, and case studies about specific volcanoes.

106

Vertical Motions of Oceanic Volcanoes  

NASA Astrophysics Data System (ADS)

Oceanic volcanoes offer abundant evidence of changes in their elevations through time. Their large-scale motions begin with a period of rapid subsidence lasting hundreds of thousands of years caused by isostatic compensation of the added mass of the volcano on the ocean lithosphere. The response is within thousands of years and lasts as long as the active volcano keeps adding mass on the ocean floor. Downward flexure caused by volcanic loading creates troughs around the growing volcanoes that eventually fill with sediment. Seismic surveys show that the overall depression of the old ocean floor beneath Hawaiian volcanoes such as Mauna Loa is about 10 km. This gross subsidence means that the drowned shorelines only record a small part of the total subsidence the islands experienced. In Hawaii, this history is recorded by long-term tide-gauge data, the depth in drill holes of subaerial lava flows and soil horizons, former shorelines presently located below sea level. Offshore Hawaii, a series of at least 7 drowned reefs and terraces record subsidence of about 1325 m during the last half million years. Older sequences of drowned reefs and terraces define the early rapid phase of subsidence of Maui, Molokai, Lanai, Oahu, Kauai, and Niihau. Volcanic islands, such as Maui, tip down toward the next younger volcano as it begins rapid growth and subsidence. Such tipping results in drowned reefs on Haleakala as deep as 2400 m where they are tipped towards Hawaii. Flat-topped volcanoes on submarine rift zones also record this tipping towards the next younger volcano. This early rapid subsidence phase is followed by a period of slow subsidence lasting for millions of years caused by thermal contraction of the aging ocean lithosphere beneath the volcano. The well-known evolution along the Hawaiian chain from high to low volcanic island, to coral island, and to guyot is due to this process. This history of rapid and then slow subsidence is interrupted by a period of minor uplift lasting a few hundred thousand years as the island migrates over a broad flexural arch related to isostatic compensation of a nearby active volcano. The arch is located about 190±30 km away from the center of volcanic activity and is also related to the rejuvenated volcanic stage on the islands. Reefs on Oahu that are uplifted several tens of m above sea level are the primary evidence for uplift as the islands over-ride the flexural arch. At the other end of the movement spectrum, both in terms of magnitude and length of response, are the rapid uplift and subsidence that occurs as magma is accumulated within or erupted from active submarine volcanoes. These changes are measured in days to years and are of cm to m variation; they are measured using leveling surveys, tiltmeters, EDM and GPS above sea level and pressure gauges and tiltmeters below sea level. Other acoustic techniques to measure such vertical movement are under development. Elsewhere, evidence for subsidence of volcanoes is also widespread, ranging from shallow water carbonates on drowned Cretaceous guyots, to mapped shoreline features, to the presence of subaerially-erupted (degassed) lavas on now submerged volcanoes. Evidence for uplift is more limited, but includes makatea islands with uplifted coral reefs surrounding low volcanic islands. These are formed due to flexural uplift associated with isostatic loading of nearby islands or seamounts. In sum, oceanic volcanoes display a long history of subsidence, rapid at first and then slow, sometimes punctuated by brief periods of uplift due to lithospheric loading by subsequently formed nearby volcanoes.

Clague, D. A.; Moore, J. G.

2006-12-01

107

Volcano Activity  

NSDL National Science Digital Library

Part of Prentice Hall's Planet Diary, this computer activity covers volcanic activity. Students research the most recent volcanic activity and the locations and names of each volcano. They then find out which tectonic plates the volcanoes are located on or if they are hot spots, and if any are part of the Ring of Fire.

108

Attack submarines  

SciTech Connect

This issue discusses missions for submarines, technology proliferation; implications for U.S. security; U.S. SSN-21 Seawolf versus other submarines; stability and arms control; nuclear propulsion and nuclear proliferation; air independent propulsion.

Not Available

1991-01-01

109

Identifying elements of the plumbing system beneath Kilauea Volcano, Hawaii, from the source locations of very-long-period signals  

USGS Publications Warehouse

We analyzed 16 seismic events recorded by the Hawaiian broad-band seismic network at Kilauca Volcano during the period September 9-26, 1999. Two distinct types of event are identified based on their spectral content, very-long-period (VLP) waveform, amplitude decay pattern and particle motion. We locate the VLP signals with a method based on analyses of semblance and particle motion. Different source regions are identified for the two event types. One source region is located at depths of ~1 km beneath the northeast edge of the Halemaumau pit crater. A second region is located at depths of ~8 km below the northwest quadrant of Kilauea caldera. Our study represents the first time that such deep sources have been identified in VLP data at Kilauea. This discovery opens the possibility of obtaining a detailed image of the location and geometry of the magma plumbing system beneath this volcano based on source locations and moment tensor inversions of VLP signals recorded by a permanent, large-aperture broad-band network.

Almendros, J.; Chouet, B.; Dawson, P.; Bond, T.

2002-01-01

110

Application of near real-time radial semblance to locate the shallow magmatic conduit at Kilauea Volcano, Hawaii  

NASA Astrophysics Data System (ADS)

Radial Semblance is applied to broadband seismic network data to provide source locations of Very-Long-Period (VLP) seismic energy in near real time. With an efficient algorithm and adequate network coverage, accurate source locations of VLP energy are derived to quickly locate the shallow magmatic conduit system at Kilauea Volcano, Hawaii. During a restart in magma flow following a brief pause in the current eruption, the shallow magmatic conduit is pressurized, resulting in elastic radiation from various parts of the conduit system. A steeply dipping distribution of VLP hypocenters outlines a region extending from sea level to about 550 m elevation below and just east of the Halemaumau Pit Crater. The distinct hypocenters suggest the shallow plumbing system beneath Halemaumau consists of a complex plexus of sills and dikes. An unconstrained location for a section of the conduit is also observed beneath the region between Kilauea Caldera and Kilauea Iki Crater.

Dawson, P.; Whilldin, D.; Chouet, B.

2004-11-01

111

Application of near real-time radial semblance to locate the shallow magmatic conduit at Kilauea Volcano, Hawaii  

USGS Publications Warehouse

Radial Semblance is applied to broadband seismic network data to provide source locations of Very-Long-Period (VLP) seismic energy in near real time. With an efficient algorithm and adequate network coverage, accurate source locations of VLP energy are derived to quickly locate the shallow magmatic conduit system at Kilauea Volcano, Hawaii. During a restart in magma flow following a brief pause in the current eruption, the shallow magmatic conduit is pressurized, resulting in elastic radiation from various parts of the conduit system. A steeply dipping distribution of VLP hypocenters outlines a region extending from sea level to about 550 m elevation below and just east of the Halemaumau Pit Crater. The distinct hypocenters suggest the shallow plumbing system beneath Halemaumau consists of a complex plexus of sills and dikes. An unconstrained location for a section of the conduit is also observed beneath the region between Kilauea Caldera and Kilauea Iki Crater.

Dawson, P.; Whilldin, D.; Chouet, B.

2004-01-01

112

Hawaiian Volcano Observatory  

USGS Publications Warehouse

Lava from Kilauea volcano flowing through a forest in the Royal Gardens subdivision, Hawai'i, in February 2008. The Hawaiian Volcano Observatory (HVO) monitors the volcanoes of Hawai'i and is located within Hawaiian Volcanoes National Park. HVO is one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and public safety. Learn more about Kilauea and HVO at http://hvo.wr.usgs.gov.

Venezky, Dina Y.; Orr, Tim

2008-01-01

113

Trace element distribution, with a focus on gold, in copper-rich and zinc-rich sulfide chimneys from Brothers submarine volcano, Kermadec arc  

NASA Astrophysics Data System (ADS)

Brothers volcano is a dacitic volcano located along the Kermadec arc, New Zealand, and hosts the NW Caldera hydrothermal vent field perched on part of the steep caldera walls. The field strikes for ~600 m between depths of 1550 and 1700 m and includes numerous, active, high-temperature (max 302°C) chimneys and even more dead, sulfide-rich spires. Chimney samples collected from Brothers show distinct mineralogical zonation reflecting gradients in oxidation state, temperature, and pH from the inner walls in contact with hydrothermal fluids through to the outer walls in contact with seawater. Minerals deposited from hotter fluids (e.g., chalcopyrite) are located in the interior of the chimneys and are surrounded by an external zone of minerals deposited by cooler fluids (e.g., sulfates, sphalerite). Four chimneys types are identified at Brothers volcano based on the relative proportions of chalcopyrite and sulfate layers, and the presence or absence of anhydrite. Two are Cu-rich, i.e., chalcopyrite-rich and chalcopyrite-bornite-rich chimneys, and two are Zn-rich, i.e., sphalerite-rich and sphalerite-chalcopyrite-rich. Barite and anhydrite are common to both Cu-rich chimney types whereas Zn-rich chimneys contain barite only. The main mineral phases in all the chimneys are anhydrite, barite, chalcopyrite, pyrite/marcasite, and sphalerite. Trace minerals include galena, covellite, tennantite, realgar, chalcocite, bornite, hematite, goethite, Pb-As sulfosalts, and Bi- or Au-tellurides. The vast majority of tellurides are <5 ?m in size and they commonly form in bands, cluster in patches, or occur along internal grain boundaries within chalcopyrite. In sulfate layers adjacent to the chalcopyrite zones tellurides can occur as inclusions in anhydrite, barite or pyrite and/or occupy void space within the chimney. The occurrence of specular hematite and Bi- or Au-tellurides associated with chalcopyrite are consistent with magmatic contributions to the NW Caldera vent site. These tellurides are the first gold-bearing phase to be identified in these chimneys, and the Bi-Au association suggests that gold-enrichment up to 91 ppm is due to scavenging by liquid bismuth. To better understand the mineral associations and zonation of these and other trace elements within the chimney walls, we have undertaken element mapping on the four different chimneys types with both X-Ray fluorescence microscopy using synchrotron radiation and with Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS). For example, in a chalcopyrite-rich chimney, visibly laminated chalcopyrite in the interior contains bands with a magmatic suite of elements including Co, Mo, Ag, Te, Au, and Bi. In comparison in a sphalerite-chalcopyrite-rich chimney, Au is again associated with minor Cu, although not with Bi and Te indicating alternative methods of gold transport and deposition are dominant. Element mapping allows us to better understand the physico-chemical gradients within chimney walls, as well as metal sources and transportation, and depositional processes.

Berkenbosch, H. A.; de Ronde, C. E.; McNeill, A.; Goemann, K.; Gemmell, J. B.

2012-12-01

114

Virtual Volcano  

NSDL National Science Digital Library

The Discovery Channel's website has several interactive features on volcanoes to complement its programs on Pompeii. At the homepage, visitors can explore a virtual volcano, by clicking on "Enter". The virtual volcano has several components. The first is a quickly revolving globe with red triangles and gray lines on it that represent active volcanoes and plate boundaries. Clicking on "Stop Rotation", located next to the globe, will enable a better look. Visitors can also click one of the topics below the globe, to see illustrations of "Tectonic Plates", "Ring of Fire" (no, not the Johnny Cash song), and "Layers Within". Visitors can click on "Build your Own Volcano and Watch it Erupt" on the menu on the left side of the page, where they will be given a brief explanation of two factors that affect the shape and explosiveness of volcanoes: viscosity and gas. Then they must choose, and set, the conditions of their volcano by using the arrows under the viscosity and gas headings, and clicking on "Set Conditions", underneath the arrows. Once done, a description of the type of volcano created will be given, and it's time to "Start Eruption". While the lava flows, and the noise of an eruption sounds, terms describing various features of the volcano are superimposed on the virtual volcano, and can be clicked on for explanations.

115

Microbial communities in sunken wood are structured by wood-boring bivalves and location in a submarine canyon.  

PubMed

The cornerstones of sunken wood ecosystems are microorganisms involved in cellulose degradation. These can either be free-living microorganisms in the wood matrix or symbiotic bacteria associated with wood-boring bivalves such as emblematic species of Xylophaga, the most common deep-sea woodborer. Here we use experimentally submerged pine wood, placed in and outside the Mediterranean submarine Blanes Canyon, to compare the microbial communities on the wood, in fecal pellets of Xylophaga spp. and associated with the gills of these animals. Analyses based on tag pyrosequencing of the 16S rRNA bacterial gene showed that sunken wood contained three distinct microbial communities. Wood and pellet communities were different from each other suggesting that Xylophaga spp. create new microbial niches by excreting fecal pellets into their burrows. In turn, gills of Xylophaga spp. contain potential bacterial symbionts, as illustrated by the presence of sequences closely related to symbiotic bacteria found in other wood eating marine invertebrates. Finally, we found that sunken wood communities inside the canyon were different and more diverse than the ones outside the canyon. This finding extends to the microbial world the view that submarine canyons are sites of diverse marine life. PMID:24805961

Fagervold, Sonja K; Romano, Chiara; Kalenitchenko, Dimitri; Borowski, Christian; Nunes-Jorge, Amandine; Martin, Daniel; Galand, Pierre E

2014-01-01

116

Microbial Communities in Sunken Wood Are Structured by Wood-Boring Bivalves and Location in a Submarine Canyon  

PubMed Central

The cornerstones of sunken wood ecosystems are microorganisms involved in cellulose degradation. These can either be free-living microorganisms in the wood matrix or symbiotic bacteria associated with wood-boring bivalves such as emblematic species of Xylophaga, the most common deep-sea woodborer. Here we use experimentally submerged pine wood, placed in and outside the Mediterranean submarine Blanes Canyon, to compare the microbial communities on the wood, in fecal pellets of Xylophaga spp. and associated with the gills of these animals. Analyses based on tag pyrosequencing of the 16S rRNA bacterial gene showed that sunken wood contained three distinct microbial communities. Wood and pellet communities were different from each other suggesting that Xylophaga spp. create new microbial niches by excreting fecal pellets into their burrows. In turn, gills of Xylophaga spp. contain potential bacterial symbionts, as illustrated by the presence of sequences closely related to symbiotic bacteria found in other wood eating marine invertebrates. Finally, we found that sunken wood communities inside the canyon were different and more diverse than the ones outside the canyon. This finding extends to the microbial world the view that submarine canyons are sites of diverse marine life.

Fagervold, Sonja K.; Romano, Chiara; Kalenitchenko, Dimitri; Borowski, Christian; Nunes-Jorge, Amandine; Martin, Daniel; Galand, Pierre E.

2014-01-01

117

Geology and petrology of Mahukona Volcano, Hawaii  

USGS Publications Warehouse

The submarine Mahukona Volcano, west of the island of Hawaii, is located on the Loa loci line between Kahoolawe and Hualalai Volcanoes. The west rift zone ridge of the volcano extends across a drowned coral reef at about-1150 m and a major slope break at about-1340 m, both of which represent former shoreines. The summit of the volcano apparently reached to about 250 m above sea level (now at-1100 m depth) did was surmounted by a roughly circular caldera. A econd rift zone probably extended toward the east or sutheast, but is completely covered by younger lavas from the adjacent subaerial volcanoes. Samples were vecovered from nine dredges and four submersible lives. Using subsidence rates and the compositions of flows which drape the dated shoreline terraces, we infer that the voluminous phase of tholeiitic shield growth ended about 470 ka, but tholeiitic eruptions continued until at least 435 ka. Basalt, transitional between tholeiitic and alkalic basalt, erupted at the end of tholeiitic volcanism, but no postshield-alkalic stage volcanism occurred. The summit of the volcano apparently subcided below sea level between 435 and 365 ka. The tholeiitic lavas recovered are compositionally diverse. ?? 1991 Springer-Verlag.

Clague, D. A.; Moore, J. G.

1991-01-01

118

Alaska Volcano Observatory Monitoring Station  

USGS Multimedia Gallery

An Alaska Volcano Observatory Monitoring station with Peulik Volcano behind. This is the main repeater for the Peulik monitoring network located on Whale Mountain, Beecharaof National Wildlife Refuge....

2009-12-08

119

A new species of Copepoda Harpacticoida, Xylora calyptogenae spec. n., with a carnivorous life-style from a hydrothermally active submarine volcano in the New Ireland ForeArc system (Papua New Guinea) with notes on the systematics of the Donsiellinae Lang, 1948  

Microsoft Academic Search

A new species of harpacticoid copepods, Xylora calyptogenae spec. n., from Edison Seamount, a hydrothermally active submarine volcano in the New Ireland Fore-Arc system (Papua New Guinea) is described. The new species belongs to the Donsiellinae Lang, 1944, a highly specialised taxon, the members of which have previously been encountered only in association with decaying wood and\\/or wood-boring isopods. A

Elke Willen; Fakultat V

2006-01-01

120

High-precision earthquake location and three-dimensional P wave velocity determination at Redoubt Volcano, Alaska  

Microsoft Academic Search

Redoubt Volcano, Alaska poses significant volcanic hazard to the Cook Inlet region and overlying flight paths. During and following the most recent eruption in 1989–1990 the Alaska Volcano Observatory deployed up to 10 seismometers to improve real-time monitoring capabilities at Redoubt and continues to produce an annual earthquake catalog with associated arrival times for this volcano. We compute a three-dimensional

Heather R. DeShon; Clifford H. Thurber; Charlotte Rowe

2007-01-01

121

Submarine Volcanic Cones in the São Miguel Region/Azores  

NASA Astrophysics Data System (ADS)

São Miguel, the main island of the Azores Archipelago, is located in an area ~1500 km west of Portugal where the American, African and Eurasian plates converge. Just as well as the other eight Azorian islands, it is of volcanic origin and therefore volcanic processes also play an important role for the evolution of its submarine domain. Around 300 submarine volcanic cones have been mapped in the vicinity of São Miguel Island with multi-beam data during RV Meteor cruise M79/2 . They are distributed in depth down to 3000 m. They exhibit an average diameter of 600 m, an average slope of 22° and heights mainly between 50 and 200 m, slightly decreasing with increasing water depth. Even if their morphological appearances show no segregation, the volcanic setting can be classified in three different categories. A numerous amount of cones are located on the submarine flank of Sete Cidades Volcano in the west of São Miguel considered as parasitic structures, whereas in the very east they build up an own superstructure possibly reflecting an early submarine stadium of a posterior subaerial stratovolcano like Sete Cidades. The third class is controlled by and orientated along faults, most of them in a graben system southwest of the Island. High-resolution multichannel seismic data depicts that the graben cones extinguished synchronously in the past most likely accompanying with the end of graben formation. Backscatter data reveal a rough surface possibly caused by currents removing the fine grain-size fraction over time. However, a young cone investigated in detail is characterized by a smooth surface, a distal increasing stratification and concave shaped flanks. Other few exhibit craters, all together indicating rather a phreatomagmatic than an effusive evolution of these structures. Very similar in size and shape to cinder cones on-shore São Miguel Island, they appear to be their submarine equivalent.

Weiß, Benedikt; Hübscher, Christian; Wolf, Daniela

2014-05-01

122

Submarine Atmospheres  

Microsoft Academic Search

Atmosphere control in submarines has developed to meet the operational requirements. Until\\u000a the end of WWII submarines were primarily semi-submersibles spending most of their time on the surface\\u000a and submerged for periods of 12 h or less. However, rudimentary control of oxygen and carbon\\u000a dioxide was available in some WWI boats. In the latter years of WWII, the requirement for longer

Waldemar Mazurek

123

White submarine  

NASA Astrophysics Data System (ADS)

While not everyone gets to live in a yellow submarine, the scientific community may get to have a decommissioned U.S. Navy nuclear submarine dedicated to it. The Sturgeon class of submarines, which scientists say are the ideal choice for the project, will be coming up for decommissioning in this next decade. So the time is ripe, scientists say. Two weeks ago, oceanographers, submarine specialists, marine biologists, and geophysicists, among others met at AGU headquarters in Washington to discuss how to get the project in the water. If all goes well, the project would be the "biggest thing that ever happened in ocean and Earth science," according to Lloyd Keigwin of the Woods Hole Oceanographic Institution, who convened the meeting. For example, the submarine could make many types of "compelling" research possible that can not be done now by other means, such as studies in the Arctic that may have significant bearing on global change research, Keigwin says. However, the imposing hurdles that the project must overcome are as big as the opportunities it offers. Foremost, there is a question as to who will pick up the tab for such an endeavor.

124

33 CFR 209.310 - Representation of submarine cables and pipelines on nautical charts.  

Code of Federal Regulations, 2013 CFR

...Representation of submarine cables and pipelines on nautical charts. 209.310 Section...Representation of submarine cables and pipelines on nautical charts. (a) The policy...the locations of submarine cables and pipelines on nautical charts published by the...

2013-07-01

125

Moment tensor inversion for the source location and mechanism of long period (LP) seismic events from 2009 at Turrialba volcano, Costa Rica  

NASA Astrophysics Data System (ADS)

Long-period (LP) seismic events were recorded during the temporary installation of a broadband seismic network of 13 stations from March to September 2009 on Turrialba volcano, Costa Rica. Over 6000 LPs were extracted using a modified STA/LTA method and a family consisting of 435 similar LP events has been identified. For the first time at Turrialba volcano, full-waveform moment tensor inversion is performed to jointly determine the location and source mechanism of the events. The LPs in the family are likely to be caused by crack mechanisms dipping towards the southwest at angles of approximately 10 to 20°, located at shallow depths (< 800 m) below the active Southwest and Central craters. As the locations are so shallow, the most probable causes of crack mechanisms are hydrothermal fluids resonating within or "pulsing" through a crack. The waveforms observed at the summit stations suggest a "pulsing" mechanism, but source resonance with a high degree of damping is also possible.

Eyre, Thomas S.; Bean, Christopher J.; De Barros, Louis; O'Brien, Gareth S.; Martini, Francesca; Lokmer, Ivan; Mora, Mauricio M.; Pacheco, Javier F.; Soto, Gerardo J.

2013-05-01

126

An efficient algorithm for double-difference tomography and location in heterogeneous media, with an application to the Kilauea volcano  

USGS Publications Warehouse

Improving our understanding of crustal processes requires a better knowledge of the geometry and the position of geological bodies. In this study we have designed a method based upon double-difference relocation and tomography to image, as accurately as possible, a heterogeneous medium containing seismogenic objects. Our approach consisted not only of incorporating double difference in tomography but also partly in revisiting tomographic schemes for choosing accurate and stable numerical strategies, adapted to the use of cross-spectral time delays. We used a finite difference solution to the eikonal equation for travel time computation and a Tarantola-Valette approach for both the classical and double-difference three-dimensional tomographic inversion to find accurate earthquake locations and seismic velocity estimates. We estimated efficiently the square root of the inverse model's covariance matrix in the case of a Gaussian correlation function. It allows the use of correlation length and a priori model variance criteria to determine the optimal solution. Double-difference relocation of similar earthquakes is performed in the optimal velocity model, making absolute and relative locations less biased by the velocity model. Double-difference tomography is achieved by using high-accuracy time delay measurements. These algorithms have been applied to earthquake data recorded in the vicinity of Kilauea and Mauna Loa volcanoes for imaging the volcanic structures. Stable and detailed velocity models are obtained: the regional tomography unambiguously highlights the structure of the island of Hawaii and the double-difference tomography shows a detailed image of the southern Kilauea caldera-upper east rift zone magmatic complex. Copyright 2005 by the American Geophysical Union.

Monteiller, V.; Got, J. -L.; Virieux, J.; Okubo, P.

2005-01-01

127

Where are the Volcanoes?  

NSDL National Science Digital Library

This formative assessment item discusses common misconceptions about volcano location around the world. Resources include background and content information as well as alignment to the National Science Education Standards. The probe could easily be modified to be used with a study of earthquakes instead of volcanoes. Teachers can access other resources including facts about volcanoes and lesson ideas.

Fries-Gaither, Jessica

128

On sonobuoy placement for submarine tracking  

NASA Astrophysics Data System (ADS)

This paper addresses the problem of detecting and tracking an unknown number of submarines in a body of water using a known number of moving sonobuoys. Indeed, we suppose there are N submarines collectively maneuvering as a weakly interacting stochastic dynamical system, where N is a random number, and we need to detect and track these submarines using M moving sonobuoys. These sonobuoys can only detect the superposition of all submarines through corrupted and delayed sonobuoy samples of the noise emitted from the collection of submarines. The signals from the sonobuoys are transmitted to a central base to analyze, where it is required to estimated how many submarines there are as well as their locations, headings, and velocities. The delays induced by the propagation of the submarine noise through the water mean that novel historical filtering methods need to be developed. We summarize these developments within and give initial results on a simplified example.

Kouritzin, Michael A.; Ballantyne, David J.; Kim, Hyukjoon; Hu, Yaozhong

2005-05-01

129

Volcanoes: Annenberg Media Project  

NSDL National Science Digital Library

Volcanoes is an exhibit from the Annenberg Media Project that provides a wealth of information about volcanoes and includes sections such as Melting Rocks, the Dynamic Earth, and Forecasting. Interactive exercises enable the user to learn how rock turns into magma, how to locate volcanoes, and how to decide if building a project near a volcano is safe. Quicktime videos are used for each of the six categories to illustrate the points outlined in the text.

1997-01-01

130

Syrian Volcano  

NASA Technical Reports Server (NTRS)

23 July 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a small volcano in the Syria Planum region of Mars. Today, the lava flows that compose this small volcano are nearly hidden by a mantle of rough-textured, perhaps somewhat cemented, dust. The light-toned streaks that cross the scene were formed by passing dust devils, a common occurrence in Syria.

Location near: 13.0oS, 102.6oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Autumn

2006-01-01

131

Source location variability and volcanic vent mapping with a small-aperture infrasound array at Stromboli Volcano, Italy  

Microsoft Academic Search

Stromboli Volcano in Italy is a persistently active, complex volcanic system. In May 2002 activity was confined to 3 major summit craters within which several active vents hosted multiple explosions each hour. During a 5-day field campaign an array of 3 low-frequency microphones was installed to investigate the coherent infrasound produced by degassing from these vents. Consistent phase lags across

Jeffrey B. Johnson

2004-01-01

132

Dive and Explore: An Interactive Exhibit That Simulates Making an ROV Dive to a Submarine Volcano, Hatfield Marine Science Visitor Center, Newport, Oregon  

Microsoft Academic Search

We have created a new interactive exhibit in which the user can sit down and simulate that they are making a dive to the seafloor with the remotely operated vehicle (ROV) named ROPOS. The exhibit immerses the user in an interactive experience that is naturally fun but also educational. This new public display is located at the Hatfield Marine Science

C. Weiland; W. W. Chadwick; W. Hanshumaker; V. Osis

2002-01-01

133

Hawaii's volcanoes revealed  

USGS Publications Warehouse

Hawaiian volcanoes typically evolve in four stages as volcanism waxes and wanes: (1) early alkalic, when volcanism originates on the deep sea floor; (2) shield, when roughly 95 percent of a volcano's volume is emplaced; (3) post-shield alkalic, when small-volume eruptions build scattered cones that thinly cap the shield-stage lavas; and (4) rejuvenated, when lavas of distinct chemistry erupt following a lengthy period of erosion and volcanic quiescence. During the early alkalic and shield stages, two or more elongate rift zones may develop as flanks of the volcano separate. Mantle-derived magma rises through a vertical conduit and is temporarily stored in a shallow summit reservoir from which magma may erupt within the summit region or be injected laterally into the rift zones. The ongoing activity at Kilauea's Pu?u ?O?o cone that began in January 1983 is one such rift-zone eruption. The rift zones commonly extend deep underwater, producing submarine eruptions of bulbous pillow lava. Once a volcano has grown above sea level, subaerial eruptions produce lava flows of jagged, clinkery ?a?a or smooth, ropy pahoehoe. If the flows reach the ocean they are rapidly quenched by seawater and shatter, producing a steep blanket of unstable volcanic sediment that mantles the upper submarine slopes. Above sea level then, the volcanoes develop the classic shield profile of gentle lava-flow slopes, whereas below sea level slopes are substantially steeper. While the volcanoes grow rapidly during the shield stage, they may also collapse catastrophically, generating giant landslides and tsunami, or fail more gradually, forming slumps. Deformation and seismicity along Kilauea's south flank indicate that slumping is occurring there today. Loading of the underlying Pacific Plate by the growing volcanic edifices causes subsidence, forming deep basins at the base of the volcanoes. Once volcanism wanes and lava flows no longer reach the ocean, the volcano continues to submerge, while erosion incises deep river valleys, such as those on the Island of Kaua?i. The edges of the submarine terraces that ring the islands, thus, mark paleocoastlines that are now as much as 2,000 m underwater, many of which are capped by drowned coral reefs.

Eakins, Barry W.; Robinson, Joel E.; Kanamatsu, Toshiya; Naka, Jiro; Smith, John R.; Takahashi, Eiichi; Clague, David A.

2003-01-01

134

How Submarines Work  

NSDL National Science Digital Library

In this article, presented by HowStuffWorks.com, shows how a submarine dives and surfaces in the water. It also shows how life support is maintained, how the submarine gets its power, how a submarine finds its way in the deep ocean and how submarines might be rescued. The article addresses many points effectively and is a good survey of the topic.

Brain, Marshall; Freudenrich, Craig

2008-10-09

135

First Survey For Submarine Hydrothermal Vents In NE Sulawesi, Indonesia  

NASA Astrophysics Data System (ADS)

The IASSHA-2001 cruise (Indonesia-Australia Survey for Submarine Hydrothermal Activity) was successfully conducted from June 1 to June 29 on board Baruna Jaya VIII. Preliminary results are reported of the first expedition to locate and study submarine hydrothermal activity in north east Sulawesi. Leg A focussed on Tomini Bay, a virtually unexplored Neogene sedimentary basin. Its objective was to test whether modern sediment-hosted hydrothermal activity occurred on the sea floor. The results of new bathymetric mapping, sediment coring and CTD/transmissometer hydrocasts negate the likely presence in central Tomini Bay of large-scale modern analogues of hydrothermal massive sulfide environments involving hydrothermal venting of basinal or magma-derived fluids into reduced sediments. It is possible that the "heat engine" required to drive circulation of basinal and hydrothermal fluids is today too weak. Surveys around Colo volcano indicate that it may be in its final stage of evolution. Leg B studied the arc and behind-arc sectors of the Sangihe volcanic island chain extending northwards from Quaternary volcanoes on the northeastern tip of Sulawesi's North Arm, near Manado. West of the main active chain and extending northwards from Manado there is a subparallel ridge surmounted by a number of high (>2000 m) seamounts of uncertain age. Fifteen relatively high-standing submarine edifices were crossed during this leg, of which nine were tested for hydrothermal activity by hydrocast and dredging. Eight sites were known from previous bathymetric surveys, and seven are new discoveries made by narrow-beam or multibeam echo sounding. Two submarine edifices at least 1000 m high were discovered in the strait immediately north of Awu volcano on Sangihe Island. One, with crest at 206 m, is surrounded by a circular platform 300m deep which we infer to be a foundered fringing reef to a formerly emergent island. The other, lacking such a platform, appears relatively young and may be parasitic to Awu volcano. It has a summit crater or small caldera, about 800 m across and breached to the northwest. A dredge hauled within the caldera returned numerous un-abraded fragments of fresh pumiceous dacite glass with prominent phenocrysts of plagioclase, orthopyroxene and clinopyroxene, plus small angular fragments of a similar but less vesicular lithology. Coatings of soft ferruginous deposit on some fragments suggest that the caldera is hydrothermally active. A highlight of the expedition was a visit to Banua Wuhu, classed as an active volcano (eruption in 1919) whose summit is just exposed at low tide. Gas bubbling, subsurface sonic activity, and venting of hydrothermal fluids with temperatures around 50ºC are known to occur on the summit at around 10 m depth, and ferruginous oxide deposits several mm thick are common. A multibeam bathymetric chart to 1000 m was prepared and deeper narrow-beam echo sounding show that Banua Wuhu is a parasitic feature on the north-western side of adjacent Mahenetang Island, also a volcanic construction, the combined edifice exceeding 3000 m in height. We recovered thoroughly altered porphyritc andesite containing disseminated pyrite and a carbonate-chlorite-clay mineral assemblage. In summary, while the IASSHA cruise located only a single but potentially significant example of modern seafloor hydrothermal activity, we collected much valuable new geological and oceanographic data on two contrasted areas in northeastern Sulawesi that with on going post-cruise processing will greatly expand our knowledge of these regions. Binns and Permana Co-Chief Scientists

McConachy, T.; Binns, R.; Permana, H.

2001-12-01

136

Hawaiian Shield Stage Submarine Volcaniclastics: Insights From HSDP Core  

NASA Astrophysics Data System (ADS)

Ocean island volcanoes are traditionally associated with the non-explosive eruption of fluid lavas, but volcaniclastic rocks comprise a significant portion of many submarine shield volcanoes. Deep drilling (3,098 m) by the Hawaiian Scientific Drilling Project (HSDP) into the flank of Mauna Kea volcano has exposed the volcaniclastics within the pedestals of a Hawaiian volcano that were previously poorly known. The HSDP continuously cored 2,019 m of submarine Mauna Kea deposits with ˜95% recovery and revealed that volcaniclastics comprise ˜55% of this section. The shallow submarine section consists of ˜80% volcaniclastics interbedded with thin ( ˜3 m) massive lava flows and the deep section is ˜35% volcaniclastics interbedded with packages of pillow lavas up to 180 m thick. Throughout the submarine section, the volcaniclastics can occur in thick packages up to ˜100 m. The emplacement of submarine volcaniclastics is not well understood. Possible origins include primary fragmentation of lava via magmatic explosivity and magma-water interactions, and secondary fragmentation via erosion. Secondary transport of material down the steep submarine flanks by gravity flows is expected to be common, as is reworking by currents. Emplacement processes are predicted to evolve as the volcano shoals. In this study major element analyses of glassy clasts in the volcaniclastics are used to distinguish monomict and polymict assemblages, which can indicate primary versus secondary fragmentation. Clast shapes reflect fragmentation mechanisms and secondary processes and this study attempts to improve on this approach with quantitative analysis of clast shapes for the HSDP volcaniclastics and for samples of known origin. The first documentation of the textures of the Mauna Kea volcaniclastics, integrated with geochemistry, petrography, and quantitative clast shape analysis and inferences about their origins and modes of transport and deposition will be presented to better understand the shoaling of Hawaiian volcanoes.

Bridges, K. P.; Garcia, M.; Houghton, B.; Thordarson, T.

2003-12-01

137

Major-Element, Sulfur, and Chlorine Compositions of Glasses from the Submarine Flank of Kilauea Volcano, Hawaii, Collected During 1998-2002 Japan Marine Science and Technology Center (JAMSTEC) Cruises.  

National Technical Information Service (NTIS)

From 1998 to 2002, four cruises by Japan Marine Science and Technology Center (JAMSTEC) research vessels explored the submarine flanks of the Hawaiian Islands (Naka and others, 2002; Takahashi and others, 2002). This collaborative Japan-USA research progr...

M. L. Coombs T. W. Sisson P. W. Lipman

2004-01-01

138

Submarine Volcanic Morphology of Santorini Caldera, Greece  

NASA Astrophysics Data System (ADS)

Santorini volcanic group form the central part of the modern Aegean volcanic arc, developed within the Hellenic arc and trench system, because of the ongoing subduction of the African plate beneath the European margin throughout Cenozoic. It comprises three distinct volcanic structures occurring along a NE-SW direction: Christianna form the southwestern part of the group, Santorini occupies the middle part and Koloumbo volcanic rift zone extends towards the northeastern part. The geology of the Santorini volcano has been described by a large number of researchers with petrological as well as geochronological data. The offshore area of the Santorini volcanic field has only recently been investigated with emphasis mainly inside the Santorini caldera and the submarine volcano of Kolumbo. In September 2011, cruise NA-014 on the E/V Nautilus carried out new surveys on the submarine volcanism of the study area, investigating the seafloor morphology with high-definition video imaging. Submarine hydrothermal vents were found on the seafloor of the northern basin of the Santorini caldera with no evidence of high temperature fluid discharges or massive sulphide formations, but only low temperature seeps characterized by meter-high mounds of bacteria-rich sediment. This vent field is located in line with the normal fault system of the Kolumbo rift, and also near the margin of a shallow intrusion that occurs within the sediments of the North Basin. Push cores have been collected and they will provide insights for their geochemical characteristics and their relationship to the active vents of the Kolumbo underwater volcano. Similar vent mounds occur in the South Basin, at shallow depths around the islets of Nea and Palaia Kameni. ROV exploration at the northern slopes of Nea Kameni revealed a fascinating underwater landscape of lava flows, lava spines and fractured lava blocks that have been formed as a result of 1707-1711 and 1925-1928 AD eruptions. A hummocky topography at the area that lies between the town of Fira on the main island of Santorini and Nea Kammeni has been revealed. The lower slopes were covered with landslide debris which consisted of lava blocks mostly mantled with soft sediment. At the upper slopes an abrupt cliff face was exposed that was highly indurated by biologic material. At the top of a volcanic dome, a crater with its deepest part at 43m, its rim at about 34m with an approximately 8m diameter was also found. Shimmery water with temperatures as much as 25°C above ambient was observed there but the source of venting has not yet been found. The combination of ROV video footage and multibeam data provide new information about the main morphological characteristics of Santorini Caldera which demonstrates the intense geodynamic processes occurring at the central part of the active Hellenic volcanic arc. These results will be useful for the interpretation of understanding the offshore volcanic area and its linkage with the onshore structures.

Nomikou, P.; Croff Bell, K.; Carey, S.; Bejelou, K.; Parks, M.; Antoniou, V.

2012-04-01

139

Global observation of vertical-CLVD earthquakes at active volcanoes  

NASA Astrophysics Data System (ADS)

AbstractSome of the largest and most anomalous volcanic earthquakes have non-double-couple focal mechanisms. Here, we investigate the link between volcanic unrest and the occurrence of non-double-couple earthquakes with dominant vertical tension or pressure axes, known as vertical compensated-linear-vector-dipole (vertical-CLVD) earthquakes. We determine focal mechanisms for 313 target earthquakes from the standard and surface wave catalogs of the Global Centroid Moment Tensor Project and identify 86 shallow 4.3 ? MW ? 5.8 vertical-CLVD earthquakes <span class="hlt">located</span> near <span class="hlt">volcanoes</span> that have erupted in the last ~100 years. The majority of vertical-CLVD earthquakes occur in subduction zones in association with basaltic-to-andesitic stratovolcanoes or <span class="hlt">submarine</span> <span class="hlt">volcanoes</span>, although vertical-CLVD earthquakes are also <span class="hlt">located</span> in continental rifts and in regions of hot spot volcanism. Vertical-CLVD earthquakes are associated with many types of confirmed or suspected eruptive activity at nearby <span class="hlt">volcanoes</span>, including volcanic earthquake swarms as well as effusive and explosive eruptions and caldera collapse. Approximately 70% of all vertical-CLVD earthquakes studied occur during episodes of documented volcanic unrest at a nearby <span class="hlt">volcano</span>. Given that volcanic unrest is underreported, most shallow vertical-CLVD earthquakes near active <span class="hlt">volcanoes</span> are likely related to magma migration or eruption processes. Vertical-CLVD earthquakes with dominant vertical pressure axes generally occur after volcanic eruptions, whereas vertical-CLVD earthquakes with dominant vertical tension axes generally occur before the start of volcanic unrest. The occurrence of these events may be useful for identifying <span class="hlt">volcanoes</span> that have recently erupted and those that are likely to erupt in the future.</p> <div class="credits"> <p class="dwt_author">Shuler, Ashley; Nettles, Meredith; EkströM, GöRan</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">140</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=https://eosweb.larc.nasa.gov/project/misr/gallery/nicaraguan_volcanoes"> <span id="translatedtitle">Nicaraguan <span class="hlt">Volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href=""></a></p> <p class="result-summary">article title:  Nicaraguan <span class="hlt">Volcanoes</span>     View Larger Image Nicaraguan <span class="hlt">volcanoes</span>, February 26, 2000 . The true-color image at left is a ... February 26, 2000 - Plumes from the San Cristobal and Masaya <span class="hlt">volcanoes</span>. project:  MISR category:  gallery ...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-18</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_6");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return 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showDiv("page_9");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">141</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/44257966"> <span id="translatedtitle">Giving birth to hotspot <span class="hlt">volcanoes</span>: Distribution and composition of young seamounts from the seafloor near Tahiti and Pitcairn islands</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Apart from being popular holiday destinations, oceanic-island <span class="hlt">volcanoes</span> such as Hawaii, Tahiti, or the Canaries provide magmas that yield valuable information about the interior of our planet. Until recently, studies have concentrated on the easily accessible, subaerial parts of the <span class="hlt">volcanoes</span>, largely ignoring their earlier-formed, <span class="hlt">submarine</span> parts. These <span class="hlt">submarine</span> parts, however, provide critical information about how the mantle begins to</p> <div class="credits"> <p class="dwt_author">C. W. Devey; K. S. Lackschewitz; D. F. Mertz; B. Bourdon; J.-L. Cheminée; J. Dubois; C. Guivel; R. Hékinian; P. Stoffers</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">142</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004AGUSM.V43C..04L"> <span id="translatedtitle">Examination of the constructional processes of <span class="hlt">submarine</span> Cerro Azul and the Galapagos Platform</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">One of the primary goals of the 2001 Drift04 cruise was to examine the constructional processes responsible for the Galapagos platform and to investigate the relationship between the platform and the overlying <span class="hlt">volcanoes</span>. Cerro Azul <span class="hlt">volcano</span> is <span class="hlt">located</span> above the steep escarpment that marks the southwestern limit of the Galapagos platform, at the leading edge of the hotspot. This area is of particular interest in light of a recent seismic tomography experiment by Toomey, Hooft, et al., which suggests that the root of the Galapagos plume is centered between Cerro Azul and adjacent Fernandina Island. During the Drift04 cruise, detailed bathymetric and sidescan sonar studies were carried out across the <span class="hlt">submarine</span> sector of Cerro Azul and 14 dredges were collected from the same area. Major element analyses of the <span class="hlt">submarine</span> lavas indicate that the lavas from the platform edge and the subaerial Cerro Azul lavas constitute a suite of petrologically-related lavas. The dredged glasses of the Drift04 cruise have MgO contents of <7.5% and are indistinguishable from published data on Cerro Azul. Whole rock analyses include a highly primitive sample (20 wt% MgO), which probably contains accumulated olivine. All the <span class="hlt">submarine</span> and subaerial lavas define coherent trends in major element space that are consistent with variable amounts of olivine and olivine+cpx fractionation. Incompatible trace element (ITE) ratios indicate that the mantle source for the <span class="hlt">submarine</span> platform flows is intermediate in composition between the magmas supplying Fernandina and Cerro Azul. Previous researchers have proposed that two mantle endmembers are interacting across the leading edge of the plume, one focused at Fernandina and the other at Floreana Island. The intermediate ITE ratios of the <span class="hlt">submarine</span> and subaerial Cerro Azul lavas are consistent both geographically and compositionally with this hypothesis. Naumann and co-workers concluded that the lavas erupted at Cerro Azul were stored in small, ephemeral magma chambers, which formed as the result of a low magma supply to the edge of the platform. We propose that the lavas of the western edge of the Galapagos Platform originate from either the same or a similar network of magma chambers as those responsible for Cerro Azul <span class="hlt">volcano</span>.</p> <div class="credits"> <p class="dwt_author">Lambert, M. K.; Harpp, K. S.; Geist, D. J.; Fornari, D. J.; Kurz, M. D.; Koleszar, A. M.; Rollins, N. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">143</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70102155"> <span id="translatedtitle">Summit crater lake observations, and the <span class="hlt">location</span>, chemistry, and pH of water samples near Mount Chiginagak <span class="hlt">volcano</span>, Alaska: 2004-2012</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Mount Chiginagak is a hydrothermally active <span class="hlt">volcano</span> 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 <span class="hlt">volcano</span> 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 (<span class="hlt">location</span> shown in fig. 2). The only other thermal feature at the <span class="hlt">volcano</span> is the Mother Goose hot springs <span class="hlt">located</span> at the base of the edifice on the northwestern flank in upper <span class="hlt">Volcano</span> 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 <span class="hlt">volcano</span> (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 <span class="hlt">locations</span>, 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> <div class="credits"> <p class="dwt_author">Schaefer, Janet R.; Scott, William E.; Evans, William C.; Wang, Bronwen; McGimsey, Robert G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">144</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40160194"> <span id="translatedtitle">Earthquake swarms preceding the 2000 eruption of Miyakejima <span class="hlt">volcano</span>, Japan</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The first sign of magma accumulating beneath Miyakejima, an island <span class="hlt">volcano</span> in the northern Izu islands, Japan, came at around 18:00 on 26 June 2000, when a swarm of earthquakes was detected by a <span class="hlt">volcano</span> seismic network on the island. Earthquakes occurred initially beneath the southwest flank near the summit and gradually migrated west of the island, where a <span class="hlt">submarine</span></p> <div class="credits"> <p class="dwt_author">K. Uhira; T. Baba; H. Mori; H. Katayama; N. Hamada</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">145</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dx.doi.org/10.1016/j.jvolgeores.2005.07.023"> <span id="translatedtitle">Argon geochronology of Kilauea's early <span class="hlt">submarine</span> history</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary"><span class="hlt">Submarine</span> alkalic and transitional basalts collected by submersible along Kilauea <span class="hlt">volcano</span>'s south flank represent early eruptive products from Earth's most active <span class="hlt">volcano</span>. Strongly alkalic basalt fragments sampled from volcaniclastic deposits below the mid-slope Hilina Bench yield 40Ar/39Ar ages from 212 ?? 38 to 280 ?? 20 ka. These ages are similar to high-precision 234 ?? 9 and 239 ?? 10 ka phlogopite ages from nephelinite clasts in the same deposits. Above the mid-slope bench, two intact alkalic to transitional pillow lava sequences protrude through the younger sediment apron. Samples collected from a weakly alkalic basalt section yield 138 ?? 30 to 166 ?? 26 ka ages and others from a transitional basalt section yield 138 ?? 115 and 228 ?? 114 ka ages. The ages are incompatible with previous unspiked K-Ar studies from samples in deep drill holes along the east rift of Kilauea. The <span class="hlt">submarine</span> birth of Kilauea <span class="hlt">volcano</span> is estimated at <300 ka. If the weakly alkalic sequence we dated is representative of the <span class="hlt">volcano</span> as a whole, the transition from alkalic to tholeiitic basalt compositions is dated at ??? 150 ka. ?? 2005 Elsevier B.V. All rights reserved.</p> <div class="credits"> <p class="dwt_author">Calvert, A. T.; Lanphere, M. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">146</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/55725121"> <span id="translatedtitle">Dating of <span class="hlt">Submarine</span> Landslides and Their Tsunami Deposits Using Hawaii as an Example</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">There have been several approaches to dating the initiation of <span class="hlt">submarine</span> landslides and the tsunamis they inevitably produce. In Hawaii, the timing of flank failures of major <span class="hlt">volcanoes</span> has been estimated by radiometric and paleomagnetic dating of the youngest shield-building flows and dikes, the apex ages of the <span class="hlt">volcanoes</span>, which can also be constrained by the oldest flows of post-collapse</p> <div class="credits"> <p class="dwt_author">G. M. McMurtry; E. Herrero-Bervera</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">147</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.amnh.org/education/resources/rfl/web/dsv/volcanoes.html"> <span id="translatedtitle">Research on the Web: Deep Sea <span class="hlt">Volcanoes</span> and Vents</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This Web research project gives students a close-up look at the dynamic forces at work in the deep seas. They'll work as scientists, making observations and recording their findings. Students begin by gathering background information on <span class="hlt">submarine</span> <span class="hlt">volcanoes</span> and mid-ocean ridges. They then compare volcanic activity on land with <span class="hlt">submarine</span> <span class="hlt">volcanoes</span>, noting the effects of near-freezing temperatures and incredibly intense pressure on <span class="hlt">volcanoes</span> on the ocean floor. They end by viewing real-time videos of deep sea vents in motion.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">148</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFM.V31G..01R"> <span id="translatedtitle">What Pyroclasts Can Tell Us About Deep <span class="hlt">Submarine</span> Pumice-Forming Silicic Eruptive Processes (Invited)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Despite the increasing recognition of pumice-forming eruption deposits in deep water arc environments, the processes involved in explosive silicic <span class="hlt">submarine</span> eruptions remain largely unexplored. Pyroclasts sampled from the Kermadec arc (SW Pacific) show that silicic pumices erupted in deep <span class="hlt">submarine</span> environments are macroscopically very similar (colour, density, texture etc) to subaerial or shallow <span class="hlt">submarine</span> erupted pumices, but show contrasting microscopic vesicle textures. Here we present data on pyroclast densities and associated vesicle sizes and number densities (number of bubbles per unit volume of glass matrix) for deep <span class="hlt">submarine</span> erupted pumices (?˜1000 m water depth) from three <span class="hlt">volcanoes</span> (Healy, Raoul SW and Havre) along the Kermadec arc. We compare these textural data with those from chemically similar, subaerially erupted pyroclasts from Raoul <span class="hlt">volcano</span> as well as newly described ';Tangaroan' fragments derived by non-explosive, buoyant detachment of <span class="hlt">submarine</span> erupted pumice from Macauley <span class="hlt">volcano</span>, also on the Kermadec arc. We use these data sets to evaluate processes in deep explosive <span class="hlt">submarine</span> eruptions and to investigate the effects of a significant overlying water column and associated increased pressure on vesiculation and fragmentation processes. We find that despite having similar ranges in vesicularity, deep <span class="hlt">submarine</span> erupted pyroclasts record a contrasting vesiculation history to subaerial erupted pyroclasts. The higher-pressure regime that deep <span class="hlt">submarine</span> pyroclasts are erupted into (i.e. higher pressures, and the contrasting density and viscosity of water versus air) appears to play a major role in bubble nucleation and growth dynamics.</p> <div class="credits"> <p class="dwt_author">Rotella, M. D.; Wilson, C. J.; Barker, S. J.; Wright, I. C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">149</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70017016"> <span id="translatedtitle">Earthquake classification, <span class="hlt">location</span>, and error analysis in a volcanic environment: implications for the magmatic system of the 1989-1990 eruptions at redoubt <span class="hlt">volcano</span>, Alaska</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Determination of the precise <span class="hlt">locations</span> of seismic events associated with the 1989-1990 eruptions of Redoubt <span class="hlt">Volcano</span> posed a number of problems, including poorly known crustal velocities, a sparse station distribution, and an abundance of events with emergent phase onsets. In addition, the high relief of the <span class="hlt">volcano</span> could not be incorporated into the hypoellipse earthquake <span class="hlt">location</span> algorithm. This algorithm was modified to allow hypocenters to be <span class="hlt">located</span> above the elevation of the seismic stations. The velocity model was calibrated on the basis of a posteruptive seismic survey, in which four chemical explosions were recorded by eight stations of the permanent network supplemented with 20 temporary seismographs deployed on and around the volcanic edifice. The model consists of a stack of homogeneous horizontal layers; setting the top of the model at the summit allows events to be <span class="hlt">located</span> anywhere within the volcanic edifice. Detailed analysis of hypocentral errors shows that the long-period (LP) events constituting the vigorous 23-hour swarm that preceded the initial eruption on December 14 could have originated from a point 1.4 km below the crater floor. A similar analysis of LP events in the swarm preceding the major eruption on January 2 shows they also could have originated from a point, the <span class="hlt">location</span> of which is shifted 0.8 km northwest and 0.7 km deeper than the source of the initial swarm. We suggest this shift in LP activity reflects a northward jump in the pathway for magmatic gases caused by the sealing of the initial pathway by magma extrusion during the last half of December. <span class="hlt">Volcano</span>-tectonic (VT) earthquakes did not occur until after the initial 23-hour-long swarm. They began slowly just below the LP source and their rate of occurrence increased after the eruption of 01:52 AST on December 15, when they shifted to depths of 6 to 10 km. After January 2 the VT activity migrated gradually northward; this migration suggests northward propagating withdrawal of magma from a plexus of dikes and/or sills <span class="hlt">located</span> in the 6 to 10 km depth range. Precise relocations of selected events prior to January 2 clearly resolve a narrow, steeply dipping, pencil-shaped concentration of activity in the depth range of 1-7 km, which illuminates the conduit along which magma was transported to the surface. A third event type, named hybrid, which blends the characteristics of both VT and LP events, originates just below the LP source, and may reflect brittle failure along a zone intersecting a fluid-filled crack. The distribution of hybrid events is elongated 0.2-0.4 km in an east-west direction. This distribution may offer constraints on the orientation and size of the fluid-filled crack inferred to be the source of the LP events. ?? 1994.</p> <div class="credits"> <p class="dwt_author">Lahr, J. C.; Chouet, B. A.; Stephens, C. D.; Power, J. A.; Page, R. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">150</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1994JVGR...62..137L"> <span id="translatedtitle">Earthquake classification, <span class="hlt">location</span>, and error analysis in a volcanic environment: implications for the magmatic system of the 1989 1990 eruptions at redoubt <span class="hlt">volcano</span>, Alaska</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Determination of the precise <span class="hlt">locations</span> of seismic events associated with the 1989-1990 eruptions of Redoubt <span class="hlt">Volcano</span> posed a number of problems, including poorly known crustal velocities, a sparse station distribution, and an abundance of events with emergent phase onsets. In addition, the high relief of the <span class="hlt">volcano</span> could not be incorporated into the HYPOELLIPSE earthquake <span class="hlt">location</span> algorithm. This algorithm was modified to allow hypocenters to be <span class="hlt">located</span> above the elevation of the seismic stations. The velocity model was calibrated on the basis of a posteruptive seismic survey, in which four chemical explosions were recorded by eight stations of the permanent network supplemented with 20 temporary seismographs deployed on and around the volcanic edifice. The model consists of a stack of homogeneous horizontal layers; setting the top of the model at the summit allows events to be <span class="hlt">located</span> anywhere within the volcanic edifice. Detailed analysis of hypocentral errors shows that the long-period (LP) events constituting the vigorous 23-hour swarm that preceded the initial eruption on December 14 could have originated from a point 1.4 km below the crater floor. A similar analysis of LP events in the swarm preceding the major eruption on January 2 shows they also could have originated from a point, the <span class="hlt">location</span> of which is shifted 0.8 km northwest and 0.7 km deeper than the source of the initial swarm. We suggest this shift in LP activity reflects a northward jump in the pathway for magmatic gases caused by the sealing of the initial pathway by magma extrusion during the last half of December. <span class="hlt">Volcano</span>-tectonic (VT) earthquakes did not occur until after the initial 23-hour-long swarm. They began slowly just below the LP source and their rate of occurrence increased after the eruption of 01:52 AST on December 15, when they shifted to depths of 6 to 10 km. After January 2 the VT activity migrated gradually northward; this migration suggests northward propagating withdrawal of magma from a plexus of dikes and/or sills <span class="hlt">located</span> in the 6 to 10 km depth range. Precise relocations of selected events prior to January 2 clearly resolve a narrow, steeply dipping, pencil-shaped concentration of activity in the depth range of 1-7 km, which illuminates the conduit along which magma was transported to the surface. A third event type, named hybrid, which blends the characteristics of both VT and LP events, originates just below the LP source, and may reflect brittle failure along a zone intersecting a fluid-filled crack. The distribution of hybrid events is elongated 0.2-0.4 km in an east-west direction. This distribution may offer constraints on the orientation and size of the fluid-filled crack inferred to be the source of the LP events.</p> <div class="credits"> <p class="dwt_author">Lahr, J. C.; Chouet, B. A.; Stephens, C. D.; Power, J. A.; Page, R. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">151</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005AGUSM.V23A..10T"> <span id="translatedtitle"><span class="hlt">Locations</span> of Long-Period Seismic Events Beneath the Soufriere Hills <span class="hlt">Volcano</span>, Montserrat, W.I., Inferred from a Waveform Semblance Method</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Analysis of long-period (LP) seismic events provides information about the internal state of a <span class="hlt">volcano</span> because LP events are attributed mainly to fluid dynamics between magma and hydrothermal reservoirs in its <span class="hlt">volcano</span> (e.g., Chouet, 1992). We analyzed LP events recorded by three borehole seismic stations (AIRS, OLVN, and TRNT) at Soufriere Hills <span class="hlt">Volcano</span> (SHV), Montserrat, W.I., during the period from March to June 2003. Borehole stations were deployed by the Caribbean Andesite Lava Island Precision Seismo-geodetic Observatory project (e.g., Shalev et al., 2003; Mattioli et al., 2004) and equipped with three-component short-period velocity seismometers with a sampling rate of 200 Hz. We selected 61 LP events with high signal-to-noise ratios. Almost all of the selected LP events are characterized by dominant periods in a range of 0.3 to 2.0 sec and durations of about 30 sec. Several LP events appear to be generated by a single source, based on the strong similarity in their waveforms. We first identified a family of LP events based on the dimensionless cross-correlation coefficient (CCC) of their spectral amplitudes of a period in a range of 0.2 to 2.0 sec, under the assumption of a fluid-driven crack model (Chouet, 1986). Seven LP events are identified as a family of LP events with high CCCs, particularly CCCs at AIRS in the vertical component greater than 0.88 in each event. This result suggested that these LP events are probably due to a repeated excitation of an identical source mechanism. We next attempted to estimate the <span class="hlt">locations</span> of the identified a family of LP events by a waveform semblance method (Kawakatsu et al., 2000; Almendros and Chouet, 2003). To apply the above method, we searched the seismic phases with a rectilinear polarization from LP events, by performing a complex polarization analysis (Vidale, 1986). These phases are identified as averaged particle motion ellipticities of all stations in a time window less than 0.50. Incident angles of the detected phases are rather shallow and range from about 30 to 70 degree. These particle motions point approximately to a shallow source <span class="hlt">located</span> beneath the SHV lava dome. Assuming the detected phases to be P-wave motions, we conducted the waveform semblance method for 0.3 to 2.0 sec bandpassed seismograms containing these phases. Waveform semblances are calculated in a 1.2 sec time window with sliding increments of 0.4 sec, assuming a constant P-wave speed (3.56 km/sec) appropriate for the SHV (Rowe, Thurber, and White, 2004). Our model space consists of 14 x 20 x 10 nodes with node spacing of 500 m, extending from -5 to 2 km in the east-west direction, from -5 to 5 km in the north-south direction, and from -1 to 4 km in depth. The coordinated center is fixed at the dome (16.712N, 62.176 W) and at sea level. The source <span class="hlt">location</span> is defined as the grid where the waveform semblance reaches its maximum. Note that <span class="hlt">location</span> uncertainties are about 1.0 km in all directions. As a result, we found that all the analyzed sources of LP events are <span class="hlt">located</span> about 2.0 km north of the dome and 3.0 km deep.</p> <div class="credits"> <p class="dwt_author">Taira, T.; Linde, A. T.; Sacks, I. S.; Shalev, E.; Malin, P. E.; Nielsen, J. M.; Voight, B.; Hidayat, D.; Mattioli, G. S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">152</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010AGUFM.P13B1371A"> <span id="translatedtitle">Mud <span class="hlt">Volcanoes</span> - Analogs to Martian Cones and Domes (by the thousands !)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Mud <span class="hlt">volcanoes</span> are mounds formed by low temperature slurries of gas, liquid, sediments and rock that erupt to the surface from depths of meters to kilometers. They are common on Earth, with estimates of thousands onshore and tens of thousands offshore. Mud <span class="hlt">volcanoes</span> occur in basins with rapidly-deposited accumulations of fine-grained sediments. Such settings are ideal for concentration and preservation of organic materials, and mud <span class="hlt">volcanoes</span> typically occur in sedimentary basins that are rich in organic biosignatures. Domes and cones, cited as possible mud <span class="hlt">volcanoes</span> by previous authors, are common on the northern plains of Mars. Our analysis of selected regions in southern Acidalia Planitia has revealed over 18,000 such features, and we estimate that more than 40,000 occur across the area. These domes and cones strongly resemble terrestrial mud <span class="hlt">volcanoes</span> in size, shape, morphology, associated flow structures and geologic setting. Geologic and mineralogic arguments rule out alternative formation mechanisms involving lava, ice and impacts. We are studying terrestrial mud <span class="hlt">volcanoes</span> from onshore and <span class="hlt">submarine</span> <span class="hlt">locations</span>. The largest concentration of onshore features is in Azerbaijan, near the western edge of the Caspian Sea. These features are typically hundreds of meters to several kilometers in diameter, and tens to hundreds of meters in height. Satellite images show spatial densities of 20 to 40 eruptive centers per 1000 km2. Many of the features remain active, and fresh mud flows as long as several kilometers are common. A large field of <span class="hlt">submarine</span> mud <span class="hlt">volcanoes</span> is <span class="hlt">located</span> in the Gulf of Cadiz, off the Atlantic coasts of Morocco and Spain. High-resolution sonar bathymetry reveals numerous km-scale mud <span class="hlt">volcanoes</span>, hundreds of meters in height. Seismic profiles demonstrate that the mud erupts from depths of several hundred meters. These <span class="hlt">submarine</span> mud <span class="hlt">volcanoes</span> are the closest morphologic analogs yet found to the features in Acidalia Planitia. We are also conducting laboratory analyses of surface samples collected from mud <span class="hlt">volcanoes</span> in Azerbaijan, Taiwan and Japan. X-ray diffraction, visible / near infrared reflectance spectroscopy and Raman spectroscopy show that the samples are dominated by mixed-layer smectite clays, along with quartz, calcite and pyrite. Thin section analysis by optical and scanning electron microscopy confirms the mineral identifications. These samples also contain chemical and morphological biosignatures, including common microfossils, with evidence of partial replacement by pyrite. The bulk samples contain approximately 1 wt% total organic carbon and 0.4 mg / gm volatile hydrocarbons. The thousands of features in Acidalia Planitia cited as analogous to terrestrial mud <span class="hlt">volcanoes</span> clearly represent an important element in the sedimentary record of Mars. Their <span class="hlt">location</span>, in the distal depocenter for massive Hesperian-age floods, suggests that they contain fine-grained sediments from a large catchment area in the martian highlands. We have proposed these features as a new class of exploration target that can provide access to minimally-altered material from significant depth. By analogy to terrestrial mud <span class="hlt">volcanoes</span>, these features may also be excellent sites for the sampling martian organics and subsurface microbial life, if such exist or ever existed.</p> <div class="credits"> <p class="dwt_author">Allen, C.; Oehler, D.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">153</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70014772"> <span id="translatedtitle">The giant <span class="hlt">submarine</span> alika debris slide, Mauna Loa, Hawaii.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">A 4000-km2 area of <span class="hlt">submarine</span> slump and slide deposits along the W flank of Mauna Loa <span class="hlt">volcano</span> has been mapped with GLORIA side-scan sonar images, seismic reflection profiles, and new bathymetry. The youngest deposits are 2 debris avalanche lobes that travelled from their breakaway area near the present shoreline as much as 100 km into the Hawaiian Deep at water depths of 4800 m. The 2 lobes partly overlap and together are designated the Alika slide. They were derived from the same source area and probably formed in rapid succession. Slumping on Mauna Loa has been most intense adjacent to the large arcuate bend in its SW rift zone, as the rift zone migrated westward away from the growing Kilauea <span class="hlt">volcano</span>. Slumping events were probably triggered by seismic activity accompanying dike injection along the rift zone. Such massive slumps, landslides and distal <span class="hlt">submarine</span> turbidity flows appear to be widespread on the flanks of Hawaiian <span class="hlt">volcanoes</span>.-from Authors</p> <div class="credits"> <p class="dwt_author">Lipman, P. W.; Normark, W. R.; Moore, J. G.; Wilson, J. B.; Gutmacher, C. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">1988-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">154</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=ADA556421"> <span id="translatedtitle">Addressing the Challenges of a Smoke-Free U.S. Navy <span class="hlt">Submarine</span> Force.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">Traditionally <span class="hlt">submarines</span> have had a smoking space. A study conducted 2007-9 concluded nonsmokers are exposed to significant levels of environmental tobacco smoke, regardless of <span class="hlt">location</span> on the <span class="hlt">submarine</span>. In 2009, a working group was established to create ...</p> <div class="credits"> <p class="dwt_author">F. Yeo J. McQuade L. Williams M. Long</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">155</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014EGUGA..1610019R"> <span id="translatedtitle">The diversity of mud <span class="hlt">volcanoes</span> in the landscape of Azerbaijan</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">As the natural phenomenon the mud volcanism (mud <span class="hlt">volcanoes</span>) of Azerbaijan are known from the ancient times. The historical records describing them are since V century. More detail study of this natural phenomenon had started in the second half of XIX century. The term "mud <span class="hlt">volcano</span>" (or "mud hill") had been given by academician H.W. Abich (1863), more exactly defining this natural phenomenon. All the previous definitions did not give such clear and capacious explanation of it. In comparison with magmatic <span class="hlt">volcanoes</span>, globally the mud ones are restricted in distribution; they mainly <span class="hlt">locate</span> within the Alpine-Himalayan, Pacific and Central Asian mobile belts, in more than 30 countries (Columbia, Trinidad Island, Italy, Romania, Ukraine, Georgia, Azerbaijan, Turkmenistan, Iran, Pakistan, Indonesia, Burma, Malaysia, etc.). Besides it, the zones of mud <span class="hlt">volcanoes</span> development are corresponded to zones of marine accretionary prisms' development. For example, the South-Caspian depression, Barbados Island, Cascadia (N.America), Costa-Rica, Panama, Japan trench. Onshore it is Indonesia, Japan, and Trinidad, Taiwan. The mud volcanism with non-accretionary conditions includes the areas of Black Sea, Alboran Sea, the Gulf of Mexico (Louisiana coast), Salton Sea. But new investigations reveal more new mud <span class="hlt">volcanoes</span> and in places which were not considered earlier as the traditional places of mud <span class="hlt">volcanoes</span> development (e.g. West Nile Rive delta). Azerbaijan is the classic region of mud <span class="hlt">volcanoes</span> development. From over 800 world mud <span class="hlt">volcanoes</span> there are about 400 onshore and within the South-Caspian basin, which includes the territory of East Azerbaijan (the regions of Shemakha-Gobustan and Low-Kura River, Absheron peninsula), adjacent water area of South Caspian (Baku and Absheron archipelagoes) and SW Turkmenistan and represents an area of great downwarping with thick (over 25 km) sedimentary series. Generally, in the modern relief the mud <span class="hlt">volcanoes</span> represent more or less large uplifts on surface, often of plane-conical shape, rising for 5 to 400 m and more over the country (for example, mud <span class="hlt">volcano</span> Toragay, 400 m height). The base diameter is from 100 m to 3-4 km and more. Like the magmatic ones, the mud <span class="hlt">volcanoes</span> are crowned with crater of convex-plane or deeply-seated shape. In Azerbaijan there are all types of mud <span class="hlt">volcanoes</span>: active, extinct, buried, <span class="hlt">submarine</span>, island, abundantly oil seeping. According to their morphology they are defined into cone-shaped, dome-shaped, ridge-shaped, plateau-shaped. The crater shapes are also various: conical, convex-plane, shield-shaped, deeply-seated, caldera-like. The most complete morphological classification was given in "Atlas of mud <span class="hlt">volcanoes</span> of Azerbaijan" (Yakubov et al., 1971). Recently (Aliyev Ad. et al., 2003) it was proposed a quite new morphological classification of mud <span class="hlt">volcanoes</span> of Azerbaijan. For the first time the mud volcanic manifestations had been defined. <span class="hlt">Volcanoes</span> are ranged according to morphological signs, crater shape and type of activity.</p> <div class="credits"> <p class="dwt_author">Rashidov, Tofig</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">156</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=GL-2002-001707&hterms=french+indian&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dfrench%2Bindian"> <span id="translatedtitle">Reunion Island <span class="hlt">Volcano</span> Erupts</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">On January 16, 2002, lava that had begun flowing on January 5 from the Piton de la Fournaise <span class="hlt">volcano</span> on the French island of Reunion abruptly decreased, marking the end of the <span class="hlt">volcano</span>'s most recent eruption. These false color MODIS images of Reunion, <span class="hlt">located</span> off the southeastern coast of Madagascar in the Indian Ocean, were captured on the last day of the eruption (top) and two days later (bottom). The <span class="hlt">volcano</span> itself is <span class="hlt">located</span> on the southeast side of the island and is dark brown compared to the surrounding green vegetation. Beneath clouds (light blue) and smoke, MODIS detected the hot lava pouring down the <span class="hlt">volcano</span>'s flanks into the Indian Ocean. The heat, detected by MODIS at 2.1 um, has been colored red in the January 16 image, and is absent from the lower image, taken two days later on January 18, suggesting the lava had cooled considerably even in that short time. Earthquake activity on the northeast flank continued even after the eruption had stopped, but by January 21 had dropped to a sufficiently low enough level that the 24-hour surveillance by the local observatory was suspended. Reunion is essentially all <span class="hlt">volcano</span>, with the northwest portion of the island built on the remains of an extinct <span class="hlt">volcano</span>, and the southeast half built on the basaltic shield of 8,630-foot Piton de la Fournaise. A basaltic shield <span class="hlt">volcano</span> is one with a broad, gentle slope built by the eruption of fluid basalt lava. Basalt lava flows easily across the ground remaining hot and fluid for long distances, and so they often result in enormous, low-angle cones. The Piton de la Fournaise is one of Earth's most active <span class="hlt">volcanoes</span>, erupting over 150 times in the last few hundred years, and it has been the subject of NASA research because of its likeness to the <span class="hlt">volcanoes</span> of Mars. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">157</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://library.thinkquest.org/17457/index.html"> <span id="translatedtitle"><span class="hlt">Volcanoes</span> Online</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This Thinkquest offers an encyclopedic look at plate tectonics and <span class="hlt">volcanoes</span>. Reference sections describe the interior of the Earth, continental drift, sea floor spreading, subduction, <span class="hlt">volcano</span> types and eruptions, lava flow, and famous <span class="hlt">volcanoes</span>. Lesson plans cover the internal structure of Earth, plate tectonic theory, and how volcanic eruptions and earthquakes affect the human environment. There is a plasticine plates activity; a <span class="hlt">volcano</span>-related game, crossword puzzle, and comics section; and a volcanic database containing descriptions and photographs of <span class="hlt">volcanoes</span> around the world.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">158</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=archimedes&pg=3&id=EJ758487"> <span id="translatedtitle">Paint-Stirrer <span class="hlt">Submarine</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">In this article, the authors discuss a unique and challenging laboratory exercise called, the paint-stir-stick <span class="hlt">submarine</span>, that keeps the students enthralled. The paint-stir-stick <span class="hlt">submarine</span> fits beautifully with the National Science Education Standards Physical Science Content Standard B, and with the California state science standards for physical…</p> <div class="credits"> <p class="dwt_author">Young, Jocelyn; Hardy, Kevin</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">159</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pbslearningmedia.org/resource/ess05.sci.ess.earthsys.tectonic/"> <span id="translatedtitle">Tectonic Plates, Earthquakes, and <span class="hlt">Volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">According to theory of plate tectonics, Earth is an active planet -- its surface is composed of many individual plates that move and interact, constantly changing and reshaping Earth's outer layer. <span class="hlt">Volcanoes</span> and earthquakes both result from the movement of tectonic plates. This interactive feature shows the relationship between earthquakes and <span class="hlt">volcanoes</span> and the boundaries of tectonic plates. By clicking on a map, viewers can superimpose the <span class="hlt">locations</span> of plate boundaries, <span class="hlt">volcanoes</span> and earthquakes.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">160</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.teachersdomain.org/resource/ess05.sci.ess.earthsys.tectonic/"> <span id="translatedtitle">Tectonic Plates, Earthquakes, and <span class="hlt">Volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">According to theory of plate tectonics, Earth is an active planet -- its surface is composed of many individual plates that move and interact, constantly changing and reshaping Earth's outer layer. <span class="hlt">Volcanoes</span> and earthquakes both result from the movement of tectonic plates. This interactive feature shows the relationship between earthquakes and <span class="hlt">volcanoes</span> and the boundaries of tectonic plates. By clicking on a map, viewers can superimpose the <span class="hlt">locations</span> of plate boundaries, <span class="hlt">volcanoes</span> and earthquakes.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2011-05-12</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_7");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a 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showDiv("page_10");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">161</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.usgs.gov/of/2001/0367/@noteDOCUMENT#texthttp://pubs.usgs.gov/of/2001/0367/pdf/of2001-0367.pdf@notePLATE#texthttp://pubs.usgs.gov/of/2001/0367/pdf/of2001-0367_plate1.pdf"> <span id="translatedtitle"><span class="hlt">Volcano</span>-hazard zonation for San Vicente <span class="hlt">volcano</span>, El Salvador</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">San Vicente <span class="hlt">volcano</span>, also known as Chichontepec, is one of many <span class="hlt">volcanoes</span> along the volcanic arc in El Salvador. This composite <span class="hlt">volcano</span>, <span class="hlt">located</span> about 50 kilometers east of the capital city San Salvador, has a volume of about 130 cubic kilometers, rises to an altitude of about 2180 meters, and towers above major communities such as San Vicente, Tepetitan, Guadalupe, Zacatecoluca, and Tecoluca. In addition to the larger communities that surround the <span class="hlt">volcano</span>, several smaller communities and coffee plantations are <span class="hlt">located</span> on or around the flanks of the <span class="hlt">volcano</span>, and major transportation routes are <span class="hlt">located</span> near the lowermost southern and eastern flanks of the <span class="hlt">volcano</span>. The population density and proximity around San Vicente <span class="hlt">volcano</span>, as well as the proximity of major transportation routes, increase the risk that even small landslides or eruptions, likely to occur again, can have serious societal consequences. The eruptive history of San Vicente <span class="hlt">volcano</span> is not well known, and there is no definitive record of historical eruptive activity. The last significant eruption occurred more than 1700 years ago, and perhaps long before permanent human habitation of the area. Nevertheless, this <span class="hlt">volcano</span> has a very long history of repeated, and sometimes violent, eruptions, and at least once a large section of the <span class="hlt">volcano</span> collapsed in a massive landslide. The oldest rocks associated with a volcanic center at San Vicente are more than 2 million years old. The <span class="hlt">volcano</span> is composed of remnants of multiple eruptive centers that have migrated roughly eastward with time. Future eruptions of this <span class="hlt">volcano</span> will pose substantial risk to surrounding communities.</p> <div class="credits"> <p class="dwt_author">Major, J. J.; Schilling, S. P.; Pullinger, C. R.; Escobar, C. D.; Howell, M. M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">162</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/51583824"> <span id="translatedtitle">Volcanic History And Eruption Scenario Of Iwate <span class="hlt">Volcano</span>, NE Japan</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Iwate <span class="hlt">Volcano</span> is one of the active <span class="hlt">volcanoes</span> in NE Japan, and is <span class="hlt">located</span> about 20km northwest of Morioka City having a population of 300 thousand. Iwate <span class="hlt">Volcano</span> is a composite storato-<span class="hlt">volcano</span>. On the based of topographical features, the <span class="hlt">volcano</span> is divided into two volcanic bodies, i.e., Nishi-Iwate and Higashi-Iwate. Nishi-Iwate <span class="hlt">Volcano</span> has a 2.5km by 1.5 km-wide caldera. Higashi-Iwate</p> <div class="credits"> <p class="dwt_author">J. Itoh</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">163</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2003EAEJA....12658W"> <span id="translatedtitle">The implementation of a <span class="hlt">volcano</span> seismic monitoring network in Sete Cidades <span class="hlt">Volcano</span>, São Miguel, Açores</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Sete Cidades is one of the three active central <span class="hlt">volcanoes</span> of S. Miguel Island, in the Azores archipelago. With a 5 kilometres wide caldera, it has the highest eruptive record in the last 5000 years with 17 intracaldera explosive events (Queiroz, 1997). Only <span class="hlt">submarine</span> volcanic eruptions occurred in Sete Cidades <span class="hlt">volcano</span>-tectonic system since the settlement of the island, in the 15th century. Small seismic swarms, some of which were interpreted as being related with magmatic and/or deep hydrothermal origin, characterize the most recent seismo-volcanic activity of Sete Cidades <span class="hlt">volcano</span>. To complement the regional seismic network, operating since the early 80's, a new local seismic network was designed and installed at Sete Cidades <span class="hlt">Volcano</span>. It includes 5 digital stations being one 5-seconds three-component station <span class="hlt">located</span> inside the caldera and four 10-seconds one-component stations placed on the caldera rim. The solution found for the digital telemetry is based on UHF 19,2 Kbps radio modems linking four of the seismic stations to a central point, where the fifth station is installed. At this site, signals are synchronised with a GPS receiver, stored in a PC and re-transmitted to the Azores University Volcanological Observatory by an 115,2 Kbps Spread Spectrum 2.4 Ghz Radio Modem Network. Seismic signal tests carried out in all the area showed that cultural and sea noise, as well as some scattering effects due to the geological nature of the terrain (composed by thick pumice and ash deposits) and the topographic effects are factors that can not be avoidable and will be present in future records. This low cost network with locally developed and assembled components, based on short-period sensors without signal filtering in the field and digital telemetry, will improve the detection and <span class="hlt">location</span> of low magnitude events in the Sete Cidades <span class="hlt">volcano</span> area. Future developments of this program will include the installation of a seismic array inside the caldera to identify and characterize LP events and volcanic tremor signals.</p> <div class="credits"> <p class="dwt_author">Wallenstein, N.; Montalvo, A.; Barata, U.; Ortiz, R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">164</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/mf2233"> <span id="translatedtitle">Bathymetry of southern Mauna Loa <span class="hlt">Volcano</span>, Hawaii</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Manua Loa, the largest <span class="hlt">volcano</span> on Earth, lies largely beneath the sea, and until recently only generalized bathymetry of this giant <span class="hlt">volcano</span> was available. However, within the last two decades, the development of multibeam sonar and the improvement of satellite systems (Global Positioning System) have increased the availability of precise bathymetric mapping. This map combines topography of the subaerial southern part of the <span class="hlt">volcano</span> with modern multibeam bathymetric data from the south <span class="hlt">submarine</span> flank. The map includes the summit caldera of Mauna Loa <span class="hlt">Volcano</span> and the entire length of the 100-km-long southwest rift zone that is marked by a much more pronounced ridge below sea level than above. The 60-km-long segment of the rift zone abruptly changes trend from southwest to south 30 km from the summit. It extends from this bend out to sea at the south cape of the island (Kalae) to 4 to 4.5 km depth where it impinges on the elongate west ridge of Apuupuu Seamount. The west <span class="hlt">submarine</span> flank of the rift-zone ridge connects with the Kahuku fault on land and both are part of the ampitheater head of a major <span class="hlt">submarine</span> landslide (Lipman and others, 1990; Moore and Clague, 1992). Two pre-Hawaiian volcanic seamounts in the map area, Apuupuu and Dana Seamounts, are apparently Cretaceous in age and are somewhat younger than the Cretaceous oceanic crust on which they are built.</p> <div class="credits"> <p class="dwt_author">Chadwick, William W.; Moore, James G.; Garcia, Michael O.; Fox, Christopher G.</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">165</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013MinDe..48..861M"> <span id="translatedtitle">The largest Au deposits in the St Ives Goldfield (Yilgarn Craton, Western Australia) may be <span class="hlt">located</span> in a major Neoarchean <span class="hlt">volcano</span>-sedimentary depo-centre</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The largest Neoarchean gold deposits in the world-class St Ives Goldfield, Western Australia, occur in an area known as the Argo-Junction region (e.g. Junction, Argo and Athena). Why this region is so well endowed with large deposits compared with other parts of the St Ives Goldfield is currently unclear, because gold deposits at St Ives are hosted by a variety of lithologic units and were formed during at least three different deformational events. This paper presents an investigation into the stratigraphic architecture and evolution of the Argo-Junction region to assess its implications for gold metallogenesis. The results show that the region's stratigraphy may be subdivided into five regionally correlatable packages: mafic lavas of the Paringa Basalt; contemporaneously resedimented feldspar-rich pyroclastic debris of the Early Black Flag Group; coarse polymictic volcanic debris of the Late Black Flag Group; thick piles of mafic lavas and sub-volcanic sills of the Athena Basalt and Condenser Dolerite; and the voluminous quartz-rich sedimentary successions of the Early Merougil Group. In the Argo-Junction region, these units have an interpreted maximum thickness of at least 7,130 m, and thus represent an unusually thick accumulation of the Neoarchean <span class="hlt">volcano</span>-sedimentary successions. It is postulated that major basin-forming structures that were active during deposition and emplacement of the voluminous successions later acted as important conduits during mineralisation. Therefore, a correlation exists between the <span class="hlt">location</span> of the largest gold deposits in the St Ives Goldfield and the thickest parts of the stratigraphy. Recognition of this association has important implications for camp-scale exploration.</p> <div class="credits"> <p class="dwt_author">McGoldrick, K. L.; Squire, R. J.; Cas, R. A. F.; Briggs, M.; Tunjic, J.; Allen, C. M.; Campbell, I. H.; Hayman, P. C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">166</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.sciencenetlinks.com/lessons.php?BenchmarkID=4&DocID=296"> <span id="translatedtitle">Erupting <span class="hlt">Volcanoes</span>!</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This lesson presents <span class="hlt">volcanoes</span> through the making of <span class="hlt">volcano</span> models. While students are constructing their physical representations of <span class="hlt">volcanoes</span>, they will be filled with questions about <span class="hlt">volcanoes</span> as well as how to build their models. This process will provide students with a tangible reference for learning about <span class="hlt">volcanoes</span> and give them a chance to problem-solve as they build their models. Students will be able to observe how the eruption changes the original form of their <span class="hlt">volcano</span> model. In this way, students see first hand how this type of phenomenon creates physical change. While students at this level may struggle to understand larger and more abstract geographical concepts, they will work directly with material that will help them build a foundation for understanding concepts of phenomena that sculpt the Earth.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">167</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.geology.sdsu.edu/how_volcanoes_work/Volcano_tectonic.html"> <span id="translatedtitle"><span class="hlt">Volcano</span>: Tectonic Environments</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This site describes where <span class="hlt">volcanoes</span> are found in terms of plate tectonics and explains why they occur at those <span class="hlt">locations</span>. S map shows that <span class="hlt">volcanoes</span> are <span class="hlt">located</span> mainly at plate boundaries. Then there are explanations for plate motion, mantle convection, and magma generation. The three types of plate boundaries are listed as divergent, convergent, and transform. There is also information about the relationship between types of boundaries and types of volcanism and the fact that intraplate volcanism describes volcanic eruptions within tectonic plates. The site features a diagram that depicts each type, with a link for more information about the Earth's internal heat energy and interior structure.</p> <div class="credits"> <p class="dwt_author">Camp, Victor</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">168</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFMNH51C1630S"> <span id="translatedtitle">Potential for SGD induced <span class="hlt">submarine</span> geohazard off southwestern Taiwan</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The <span class="hlt">submarine</span> groundwater discharge (SGD) is not only play important roles on material exchange between land and sea, it may also trigger liquefaction process and induce further <span class="hlt">submarine</span> geohazards in coastal zone. Since 2006, Southern Taiwan was experienced a series of natural hazards including earthquakes and typhoon that induced severe landslides and flooding and caused huge human lives and economics losses. These natural hazards also touched off <span class="hlt">submarine</span> cable-break incidents off southwestern Taiwan from Gaoping Slope to the northern terminus of the Manila Trench. After the 2006 Pingtung Earthquake, the local fishermen reported disturbed waters at the Fangliao <span class="hlt">submarine</span> canyon head. Although many researches conjectured the disturbed waters may caused by the eruption of <span class="hlt">submarine</span> <span class="hlt">volcanoes</span> which has been widely discovered off the southwestern Taiwan. The subbottom profiles reveal a series of faults and liquefaction strata exist near the head of Fanliao <span class="hlt">submarine</span> canyon and acoustically transparent sediments with doming structures also observed at the adjacent area. Moreover, we also found pockmarks with acoustic blanking under it on the Gaoping Shelf and a series of gaseous pluming gushed from the seafloor was also observed in the shallow waters. Integrate all these data, we may reasonably infer the disturbed waters which reported by the fishermen may caused by the liquefaction process on the seafloor. In addition to geophysical observations, natural geochemical tracers (radon and radium) in conjunction with side-scan sonar were used to evaluate the distribution of SGD system in the study area. All the evidences indicate that the large earthquake in conjunction with high pore fluid pressures in the surface sediment might have easily triggered liquefaction process and generated large debris flow and swept the <span class="hlt">submarine</span> cables away from the Fangliao <span class="hlt">submarine</span> canyon head to the abyss.</p> <div class="credits"> <p class="dwt_author">Su, C.; Lin, C.; Cheng, Y.; Chiu, H.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">169</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://scrippsblogs.ucsd.edu/explorations/files/2013/09/SUBMARINE_A_Journey_into_Science_Discovery.pdf#page=4"> <span id="translatedtitle"><span class="hlt">Submarine</span>: Lift Bag Lander</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">In this activity (on page 4), learners create a <span class="hlt">submarine</span> using a plastic sandwich bag. This is a fun way to learn about buoyancy and how captured gas can cause objects to float. Note: You will also need access to a tank or swimming pool to watch your <span class="hlt">submarine</span> dive. Safety note: Learners will need an adult's help to drill holes in the film canister.</p> <div class="credits"> <p class="dwt_author">Cameron, James; Hardy, Kevin</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">170</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/54014898"> <span id="translatedtitle">Preliminary Holocene Eruptive History of Ambang <span class="hlt">Volcano</span>, North Sulawesi, Indonesia</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Stratigraphic field work and radiocarbon dating at Ambang <span class="hlt">volcano</span>, North Sulawesi, Indonesia reveal that the <span class="hlt">volcano</span> erupted at least four times and likely more during the Holocene. Ambang <span class="hlt">volcano</span> is a large (about 20 km2) dome complex emplaced in a northeast-trending tectonic depression. The <span class="hlt">volcano</span> is <span class="hlt">located</span> in the southern end of the depression, where it is bounded by the</p> <div class="credits"> <p class="dwt_author">C. Harpel; K. Hendratno; F. Ruskanda Bina; J. S. Pallister; J. Griswold</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">171</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/441336"> <span id="translatedtitle">Utilization of reactor bays of decommissioned <span class="hlt">submarines</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Radiation concerns regarding dismantling and storage of decommissioned reactors and reactor bays from nuclear <span class="hlt">submarines</span> are briefly summarized. Calculation results are presented for gamma dose rates, contamination density, and the expected <span class="hlt">location</span> of maximum exposure dose rate on the <span class="hlt">submarine</span> hull. However, it is noted that radiation measurements must be obtained for each ship due to differences in operating conditions. Long-term storage options for containerized reactors and reactor bays are very briefly outlined; these include placing them in concrete-lined trenches shielded from the atmosphere or in underground tunnels shielded from water. 5 refs., 1 fig., 1 tab.</p> <div class="credits"> <p class="dwt_author">Lugavtsov, O.V.; Malakhov, A.G.; Popkov, K.K.</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">172</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFM.V31G..05W"> <span id="translatedtitle">Subtle and Not-So-Subtle Variability in Very-Long-Period Earthquakes at Fuego <span class="hlt">Volcano</span>, Guatemala Reveal Details on Vent <span class="hlt">Location</span> and Eruption Style</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Repeated short-term deployments of seismic, infrasound, video, and gas-emission instruments at Fuego <span class="hlt">volcano</span>, Guatemala have revealed three types of very-long-period (VLP) earthquakes associated with conduit sealing, pressure accumulation, and release. Major differences in waveforms are due to changes in vent <span class="hlt">locations</span>. Vulcanian explosions and gas puffing from the summit vent produce waveforms that differ only slightly in peak period. Vulcanian explosions from a flank vent produce very different VLP waveforms. In January 2008, ash-rich, vulcanian explosions issued from a vent on the western flank and produced a distinct type of VLP (Type 1). Bomb-rich explosions from the summit vent in January 2009 produced a much shorter duration VLP (Type 2), but a vulcanian-style ash release. Type 3 VLP events occurred during ash-free exhalations from the summit vent in January 2008; waveforms for Type 2 and 3 VLP events were similar although Type 3 were lower amplitude and shorter in duration. Weak infrasound records for Type 1 explosions compared to Type 2 suggest lower magma pressures and higher porosity for Type 1. Type 3 events correlate with spikes in SO2 emission rate and are driven by partial sealing and rapid release of ash-free gas at the summit vent. In 2012, both vents were active again and produced waveforms like those observed in earlier deployments. We also had a 9-station network of broadband stations that allow for improved waveform modeling. We suggest variations in the VLP period may provide a new tool for monitoring conditions within the conduit.xamples of VLP waveforms from Type 1 explosions (red, in a), Type 2 explosions (blue in b) and Type 3 puffing exhalations (black in c) and their spectra (d) highlight the waveform shape and frequency content of each. All data were deconvolved and filtered with the same 2-pole acausal Butterworth filter with corners at 60 and 12 seconds. In each of the plots, the fine lines are for individual events and the thick lines are stacked waveforms or spectra. The spectra (d) are stacks of normalized spectra for all the events.</p> <div class="credits"> <p class="dwt_author">Waite, G. P.; Brill, K. A.; Lyons, J. J.; Nadeau, P. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">173</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012PhDT.......302S"> <span id="translatedtitle">Investigations of Anomalous Earthquakes at Active <span class="hlt">Volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This dissertation investigates the link between volcanic unrest and the occurrence of moderate-to-large earthquakes with a specific type of focal mechanism. Vertical compensated-linear-vector-dipole (vertical-CLVD) earthquakes have vertical pressure or tension axes and seismic radiation patterns that are inconsistent with the double-couple model of slip on a planar fault. Prior to this work, moderate-to-large vertical-CLVD earthquakes were known to be geographically associated with volcanic centers, and vertical-CLVD earthquakes were linked to a tsunami in the Izu-Bonin volcanic arc and a subglacial fissure eruption in Iceland. Vertical-CLVD earthquakes are some of the largest and most anomalous earthquakes to occur in volcanic systems, yet their physical mechanisms remain controversial largely due to the small number of observations. Five vertical-CLVD earthquakes with vertical pressure axes are identified near Nyiragongo <span class="hlt">volcano</span> in the Democratic Republic of the Congo. Three earthquakes occur within days of a fissure eruption at Nyiragongo, and two occur several years later in association with the refilling of the lava lake in the summit crater of the <span class="hlt">volcano</span>. Detailed study of these events shows that the earthquakes have slower source processes than tectonic earthquakes with similar magnitudes and <span class="hlt">locations</span>. All five earthquakes are interpreted as resulting from slip on inward-dipping ring-fault structures <span class="hlt">located</span> above deflating shallow magma chambers. The Nyiragongo study supports the interpretation that vertical-CLVD earthquakes may be causally related to dynamic physical processes occurring inside the edifices or magmatic plumbing systems of active <span class="hlt">volcanoes</span>. Two seismicity catalogs from the Global Centroid Moment Tensor (CMT) Project are used to search for further examples of shallow earthquakes with robust vertical-CLVD focal mechanisms. CMT solutions for approximately 400 target earthquakes are calculated and 86 vertical-CLVD earthquakes are identified near active <span class="hlt">volcanoes</span>. Together with the Nyiragongo study, this work increases the number of well-studied vertical-CLVD earthquakes from 14 to 101. Vertical-CLVD earthquakes have focal depths in the upper ˜10 km of the Earth's crust, and ˜80% have centroid <span class="hlt">locations</span> within 30 km of an active volcanic center. Vertical-CLVD earthquakes are observed near several different types of <span class="hlt">volcanoes</span> in a variety of geographic and tectonic settings, but most vertical-CLVD earthquakes are observed near basaltic-to-andesitic stratovolcanoes and <span class="hlt">submarine</span> <span class="hlt">volcanoes</span> in subduction zones. Vertical-CLVD earthquakes are linked to tsunamis, volcanic earthquake swarms, effusive and explosive eruptions, and caldera collapse, and approximately 70% are associated with documented volcanic eruptions or episodes of volcanic unrest. Those events with vertical pressure axes typically occur after volcanic eruptions initiate, whereas events with vertical tension axes commonly occur before the start of volcanic unrest. Both types of vertical-CLVD earthquakes have longer source durations than tectonic earthquakes of the same magnitude. The isotropic and pure vertical-CLVD components of the moment tensor cannot be independently resolved using our long-period seismic dataset. As a result, several physical mechanisms can explain the retrieved deviatoric vertical-CLVD moment tensors, including dip-slip motion on ring faults, volume exchange between two reservoirs, the opening and closing of tensile cracks, and volumetric sources. An evaluation of these mechanisms is performed using constraints obtained from detailed studies of individual vertical-CLVD earthquakes. Although no single physical mechanism can explain all of the characteristics of vertical-CLVD earthquakes, a ring-faulting model consisting of slip on inward- or outward-dipping ring faults triggered by the inflation or deflation of a shallow magma chamber can account for their seismic radiation patterns and source durations, as well as their temporal relationships with volcanic unrest. The observation that most vertical-CLVD earthquakes a</p> <div class="credits"> <p class="dwt_author">Shuler, Ashley Elizabeth</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">174</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010AGUFMOS51D..01B"> <span id="translatedtitle">Dynamic Controls of Fluid and Gas Flow at North Alex Mud <span class="hlt">Volcano</span>, West Nile Delta</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The North Alex Mud <span class="hlt">Volcano</span> (NAMV) is <span class="hlt">located</span> at a water depth of 500m above a large deep-seated gas reservoir on the upper slope of the western Nile deep-sea fan. It has been the object of an integrated study of fluid and gas flow using existing and newly developed observatory technologies to better constrain and quantify devolatilisation and defluidisation patterns and their long-term variability in relation to underlying hydrocarbon reservoirs. As it is known that the activity of mud <span class="hlt">volcanoes</span> varies significantly over periods of months and weeks, the assessment of the activity of NAMV focuses on proxies of fluid and gas emanations. <span class="hlt">Submarine</span> mud <span class="hlt">volcanoes</span> are usually characterized by fluid formation and fluidization processes occuring at depths of several kilometers below the seafloor, driving a complex system of interacting geochemical, geological and microbial processes. Mud <span class="hlt">volcanoes</span> are natural leakages of oil and gas reservoirs. Near-surface observations made at such sites can therefore be used to monitor phenomena that occur at greater depth. Since the initiation of the project in 2007, NAMV has arguably become one of the best-instrumented mud <span class="hlt">volcanoes</span> worldwide with a network of observatories collecting long-term records of chemical fluxes, seismicity, temperature, ground deformation, and methane concentration. In addition five research cruises collected complementary geophysical and geological data and samples. In the summer of 2010 a large number of monitoring systems has been recovered which provide us with a synoptic view of the internal dynamics of an active mud <span class="hlt">volcano</span>. We will present an integrated analysis based on ship-based and sea-floor observations.</p> <div class="credits"> <p class="dwt_author">Brueckmann, W.; Bialas, J.; Jegen, M. D.; Lefeldt, M. R.; Hoelz, S.; Feseker, T.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">175</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dx.doi.org/10.1016/j.margeo.2005.05.005"> <span id="translatedtitle">Physical and chemical properties of <span class="hlt">submarine</span> basaltic rocks from the <span class="hlt">submarine</span> flanks of the Hawaiian Islands</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">To evaluate physical and chemical diversity in <span class="hlt">submarine</span> basaltic rocks, approximately 280 deep <span class="hlt">submarine</span> samples recovered by submersibles from the underwater flanks of the Hawaiian Islands were analyzed and compared. Based on observations from the submersibles and hand specimens, these samples were classified into three main occurrence types (lavas, coarse-grained volcaniclastic rocks, and fine-grained sediments), each with several subtypes. The whole-rock sulfur content and porosity in <span class="hlt">submarine</span> basaltic rocks, recovered from depths greater than 2000 m, range from < 10 ppm and 2 vol.% to 2200 ppm and 47 vol.%, respectively. These wide variations cannot be due just to different ambient pressures at the collection depths, as inferred previously for <span class="hlt">submarine</span> erupted lavas. The physical and chemical properties of the recovered samples, especially a combination of three whole-rock parameters (Fe-oxidation state, Sulfur content, and Porosity), are closely related to the occurrence type. The FSP triangular diagram is a valuable indicator of the source <span class="hlt">location</span> of basaltic fragments deposited in deep <span class="hlt">submarine</span> areas. This diagram can be applied to basaltic rocks such as clasts in debris-flow deposits, <span class="hlt">submarine</span>-emplaced lava flows that may have crossed the shoreline, and slightly altered geological samples. ?? 2005 Elsevier B.V. All rights reserved.</p> <div class="credits"> <p class="dwt_author">Yokose, H.; Lipman, P. W.; Kanamatsu, T.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">176</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/54151227"> <span id="translatedtitle">Magma accumulation process of new silicic caldera <span class="hlt">volcano</span>: A case study on the Hijiori <span class="hlt">volcano</span>, Northeastern Japan arc</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In order to know how silicic caldera <span class="hlt">volcanos</span> commence the activity, magma accumulation process of the Hijiori <span class="hlt">volcano</span> was studied. The Hijiori <span class="hlt">volcano</span> is one of the 108 active <span class="hlt">volcanoes</span> in Japan, which erupted at about 12,000 years ago (in Calendar age) on the <span class="hlt">location</span> where no volcanic body existed before the activity. Total eruptive volume of the Hijiori caldera</p> <div class="credits"> <p class="dwt_author">I. Miyagi</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">177</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/5613159"> <span id="translatedtitle">A <span class="hlt">submarine</span> canyon conduit under typhoon conditions off Southern Taiwan</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The function of a <span class="hlt">submarine</span> conduit under typhoon conditions is examined. The study site is the Kao-ping river, shelf, and <span class="hlt">submarine</span> canyon (KPRSC) system <span class="hlt">located</span> off southern Taiwan on a wave-dominated microtidal coast. The head of the canyon is <span class="hlt">located</span> approximately 1km off the river mouth. Two comprehensive 1-month field experiments were carried out in 2000 and 2002 during the</p> <div class="credits"> <p class="dwt_author">James T. Liu; Hui-Ling Lin; Jia-Jang Hung</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">178</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006EOSTr..87R.435Z"> <span id="translatedtitle">Explosion at dormant Alaskan <span class="hlt">volcano</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Fourpeaked <span class="hlt">volcano</span>, which is <span class="hlt">located</span> in a remote part of Alaska, and which has had no known activity in the last 10,000 years, released ash, gas, and steam on 17 September, according to the Alaska <span class="hlt">Volcano</span> Observatory (AVO). The <span class="hlt">volcano</span> has continued to release sulfur dioxide at a rate that is similar to that measured before the January 2006 eruptions of Alaska's Augustine <span class="hlt">volcano</span>. This indicates there is abundant, new magma within a few kilometers of the surface, said AVO research geophysicist Peter Cervelli of the U.S. Geological Survey. AVO has issued a hazard concern level of `yellow' for the <span class="hlt">volcano</span> (the <span class="hlt">volcano</span> previously had no level of concern), warning that the <span class="hlt">volcano</span> could erupt within the next days, months, or years. The Fourpeaked <span class="hlt">volcano</span> had been unmonitored. Weather-permitting, AVO plans to soon install on the mountain a web camera, short-period seismometer, and pressure sensor to detect explosions, said Cervelli. Fourpeaked Mountain is <span class="hlt">located</span> 320 kilometers southwest of Anchorage on the Alaska Peninsula. Additional information is available at http://www.avo.alaska.edu/activity/Fourpeaked.php</p> <div class="credits"> <p class="dwt_author">Zielinski, Sarah</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">179</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.sciencenetlinks.com/lessons.php?BenchmarkID=11&DocID=320"> <span id="translatedtitle">Model <span class="hlt">Volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">In this lesson, students will explore <span class="hlt">volcanoes</span> by constructing models and reflect upon their learning through drawing sketches of their models. Once they have finished making their models, they will experiment with making their <span class="hlt">volcanoes</span> erupt. They will observe how eruption changes the original form of their <span class="hlt">volcano</span> models. In this way, students see first hand how this type of phenomena creates physical change. While students at this level may struggle to understand larger and more abstract geographical concepts, they will work directly with material that will help them build a foundation for understanding concepts of phenomena that sculpt the earth.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">180</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://school.discovery.com/lessonplans/programs/understanding/index.html"> <span id="translatedtitle">Understanding <span class="hlt">Volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This lesson plan is part of the DiscoverySchool.com lesson plan library for grades K-5. It focuses on plate tectonics and <span class="hlt">volcanoes</span> acting as a cooling vent for the inner core of the Earth. Students build model <span class="hlt">volcanoes</span> and use them as comparisons for actual <span class="hlt">volcanoes</span>. Included are objectives, materials, procedures, discussion questions, evaluation ideas, suggested readings, and vocabulary. There are videos available to order which complement this lesson, an audio-enhanced vocabulary list, and links to teaching tools for making custom quizzes, worksheets, puzzles and lesson plans.</p> <div class="credits"> <p class="dwt_author">Hoffman, Dianne</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_8");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span 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</span> </span> <a id="NextPageLink" onclick='return showDiv("page_11");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">181</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.usgs.gov/sir/2007/5174/a/"> <span id="translatedtitle"><span class="hlt">Volcano</span> Hazards Assessment for Medicine Lake <span class="hlt">Volcano</span>, Northern California</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Medicine Lake <span class="hlt">volcano</span> (MLV) is a very large shield-shaped <span class="hlt">volcano</span> <span class="hlt">located</span> in northern California where it forms part of the southern Cascade Range of <span class="hlt">volcanoes</span>. It has erupted hundreds of times during its half-million-year history, including nine times during the past 5,200 years, most recently 950 years ago. This record represents one of the highest eruptive frequencies among Cascade <span class="hlt">volcanoes</span> and includes a wide variety of different types of lava flows and at least two explosive eruptions that produced widespread fallout. Compared to those of a typical Cascade stratovolcano, eruptive vents at MLV are widely distributed, extending 55 km north-south and 40 km east-west. The total area covered by MLV lavas is >2,000 km2, about 10 times the area of Mount St. Helens, Washington. Judging from its long eruptive history and its frequent eruptions in recent geologic time, MLV will erupt again. Although the probability of an eruption is very small in the next year (one chance in 3,600), the consequences of some types of possible eruptions could be severe. Furthermore, the documented episodic behavior of the <span class="hlt">volcano</span> indicates that once it becomes active, the <span class="hlt">volcano</span> could continue to erupt for decades, or even erupt intermittently for centuries, and very likely from multiple vents scattered across the edifice. Owing to its frequent eruptions, explosive nature, and proximity to regional infrastructure, MLV has been designated a 'high threat <span class="hlt">volcano</span>' by the U.S. Geological Survey (USGS) National <span class="hlt">Volcano</span> Early Warning System assessment. Volcanic eruptions are typically preceded by seismic activity, but with only two seismometers <span class="hlt">located</span> high on the <span class="hlt">volcano</span> and no other USGS monitoring equipment in place, MLV is at present among the most poorly monitored Cascade <span class="hlt">volcanoes</span>.</p> <div class="credits"> <p class="dwt_author">Donnelly-Nolan, Julie M.; Nathenson, Manuel; Champion, Duane E.; Ramsey, David W.; Lowenstern, Jacob B.; Ewert, John W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">182</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://gallery.usgs.gov/photos/12_08_2009_d2Yk05Nba7_12_08_2009_5"> <span id="translatedtitle">Cascade <span class="hlt">Volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://gallery.usgs.gov/">USGS Multimedia Gallery</a></p> <p class="result-summary">The <span class="hlt">volcanoes</span> from closest to farthest are Mt. Washington, Three Fingered Jack, Mt. Jefferson. This picture is taken from Middle Sister looking north in the Cascade Range, Three Sisters Wilderness Area, Deschutes National Forest, Oregon....</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2009-12-08</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">183</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19950004572&hterms=dante&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Ddante"> <span id="translatedtitle">Dante's <span class="hlt">Volcano</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">This video contains two segments: one a 0:01:50 spot and the other a 0:08:21 feature. Dante 2, an eight-legged walking machine, is shown during field trials as it explores the inner depths of an active <span class="hlt">volcano</span> at Mount Spurr, Alaska. A NASA sponsored team at Carnegie Mellon University built Dante to withstand earth's harshest conditions, to deliver a science payload to the interior of a <span class="hlt">volcano</span>, and to report on its journey to the floor of a <span class="hlt">volcano</span>. Remotely controlled from 80-miles away, the robot explored the inner depths of the <span class="hlt">volcano</span> and information from onboard video cameras and sensors was relayed via satellite to scientists in Anchorage. There, using a computer generated image, controllers tracked the robot's movement. Ultimately the robot team hopes to apply the technology to future planetary missions.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">184</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFMOS53B1692S"> <span id="translatedtitle">Sedimentary facies in <span class="hlt">submarine</span> canyons</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Submarine</span> canyons are the major conduits by which sediment, pollutants and nutrients are transported from the continental shelf out into the deep sea. The sedimentary facies within these canyons are remarkably poorly understood because it has proven difficult to accurately sample these heterogeneous and bathymetrically complex environments using traditional ship-based coring techniques. This study exploits a suite of over 100 precisely <span class="hlt">located</span> vibracores collected using remotely operated vehicles in ten canyons along the northern Californian margin, enabling better understanding of the facies that exist within <span class="hlt">submarine</span> canyons, their distribution, and the processes responsible for their formation. The dataset reveals three major facies types within the <span class="hlt">submarine</span> canyons: extremely poorly sorted, coarse-grained sands and gravels with complex and indistinct internal grading patterns and abundant floating clasts; classical normally graded thin bedded turbidites; and a variety of fine-grained muddy deposits. Not all facies are observed within individual canyons, in particular coarse-grained deposits occur exclusively in canyons where the canyon head cuts up to the modern day beach, whereas finer grained deposits have a more complex distribution that relates to processes of sediment redistribution on the shelf. Pairs of cores collected within 30 meters elevation of one another reveal that the coarse-grained chaotic deposits are restricted to the basal canyon floor, with finer-grained deposits at higher elevations on the canyon walls. The remarkable heterogeneity of the facies within these sediment cores illustrate that distinctive processes operate locally within the canyon. In the authors' experience the canyon floor facies represent an unusual facies rarely observed in ancient outcrops, which potentially results from the poor preservation of ancient coarse-grained canyon deposits in the geological record.</p> <div class="credits"> <p class="dwt_author">Sumner, E.; Paull, C. K.; Gwiazda, R.; Anderson, K.; Lundsten, E. M.; McGann, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">185</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFM.S23B2499J"> <span id="translatedtitle"><span class="hlt">Volcano</span> Infrasound</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Open-vent <span class="hlt">volcanoes</span> generate prodigious low frequency sound waves that tend to peak in the infrasound (<20 Hz) band. These long wavelength (> ~20 m) atmospheric pressure waves often propagate long distances with low intrinsic attenuation and can be well recorded with a variety of low frequency sensitive microphones. Infrasound records may be used to remotely monitor eruptions, identify active vents or track gravity-driven flows, and/or characterize source processes. Such studies provide information vital for both scientific study and <span class="hlt">volcano</span> monitoring efforts. This presentation proposes to summarize and standardize some of the terminology used in the still young, yet rapidly growing field of <span class="hlt">volcano</span> infrasound. Herein we suggest classification of typical infrasound waveform types, which include bimodal pulses, blast (or N-) waves, and a variety of infrasonic tremors (including broadband, harmonic, and monotonic signals). We summarize various metrics, including reduced pressure, intensity, power, and energy, in which infrasound excess pressures are often quantified. We also describe the spectrum of source types and radiation patterns, which are typically responsible for recorded infrasound. Finally we summarize the variety of propagation paths that are common for <span class="hlt">volcano</span> infrasound radiating to local (<10 km), regional (out to several hundred kilometers), and global distances. The effort to establish common terminology requires community feedback, but is now timely as <span class="hlt">volcano</span> infrasound studies proliferate and infrasound becomes a standard component of <span class="hlt">volcano</span> monitoring.</p> <div class="credits"> <p class="dwt_author">Johnson, J. B.; Fee, D.; Matoza, R. S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">186</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=https://scout.wisc.edu/Reports/ScoutReport/2002/scout-020830#IntheNews"> <span id="translatedtitle">Researchers Find Japanese <span class="hlt">Submarine</span> at Pearl Harbor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">Earlier this week, researchers from the University of Hawaii and the Hawaii Underwater Research Lab <span class="hlt">located</span> the remains of a Japanese midget <span class="hlt">submarine</span>. Found in 1200 feet of water, the <span class="hlt">submarine</span> was sunk by the USS Ward just an hour before the aerial attack on Pearl Harbor on December 7, 1941. Most important, the discovery of the midget <span class="hlt">submarine</span> offers concrete physical evidence that the United States did fire the first shot against the Japanese. Previous expeditions to <span class="hlt">locate</span> the sub, including an effort made in 2000 by the National Geographic Society, had been unsuccessful, largely due to the fact that the area is a military "junkyard" with tons of debris on the ocean floor.For more in-depth information on this story, readers may find the first four news links particularly helpful. The fifth link leads to the Hawaii Underwater Research Lab's Web site that features photographs of the midget sub from the expedition earlier this week. The sixth link is to a Web site dealing with the history and missions of the USS Ward. The final link contains detailed information about the 2000 expedition led by Robert Ballard, with support from the National Geographic Society, to find the midget <span class="hlt">submarine</span>.</p> <div class="credits"> <p class="dwt_author">Green, Marcia.</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">187</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://scrippsblogs.ucsd.edu/explorations/files/2013/09/SUBMARINE_A_Journey_into_Science_Discovery.pdf#page=2"> <span id="translatedtitle"><span class="hlt">Submarine</span>: Soda Cup Lander</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">In this activity (on page 2), learners create a <span class="hlt">submarine</span> using a plastic cup. This is a fun way to learn about buoyancy and density. Extensions for this activity, such as adding a propeller or manometer, are also included. Note: You will also need access to a tank or swimming pool to watch your <span class="hlt">submarine</span> dive. Safety note: Learners will need an adult's help to drill holes in the film canister. Learners will also need an adult's help if they use a glue gun to attach the film canister to the plastic cup.</p> <div class="credits"> <p class="dwt_author">Cameron, James; Hardy, Kevin</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">188</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://learningcenter.nsta.org/product_detail.aspx?id=10.2505/4/ss07_030_06_32"> <span id="translatedtitle">Paint-Stirrer <span class="hlt">Submarine</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">In today's fast-paced, technological world, it is a constant struggle for teachers to find new and exciting ways to challenge and engage our students. The Paint-Stirrer <span class="hlt">Submarine</span> is a unique and challenging laboratory exercise that keeps the students enthralled. They won't even realize they are learning because they will be having too much fun. This inquiry-based, hands-on experience in building a <span class="hlt">submarine</span> allows the students to learn about buoyancy, buoyant force, Archimedes' principle, and motion in an engaging manner. It will be an experience neither you nor your students will ever forget.</p> <div class="credits"> <p class="dwt_author">Young, Jocelyn; Hardy, Kevin</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">189</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dx.doi.org/10.1007/BF02326088"> <span id="translatedtitle">Acoustic stratigraphy and hydrothermal activity within Epi <span class="hlt">Submarine</span> Caldera, Vanuatu, New Hebrides Arc</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Geological and geophysical surveys of active <span class="hlt">submarine</span> <span class="hlt">volcanoes</span> offshore and southeast of Epi Island, Vanuatu, New Hebrides Arc, have delineated details of the structure and acoustic stratigraphy of three volcanic cones. These <span class="hlt">submarine</span> cones, named Epia, Epib, and Epic, are aligned east-west and spaced 3.5 km apart on the rim of a submerged caldera. At least three acoustic sequences, of presumed Quaternary age, can be identified on single-channel seismic-reflection profiles. Rocks dredged from these cones include basalt, dacite, and cognate gabbroic inclusions with magmatic affinities similar to those of the Karua (an active <span class="hlt">submarine</span> <span class="hlt">volcano</span> off the southeastern tip of Epi) lavas. ?? 1988 Springer-Verlag New York Inc.</p> <div class="credits"> <p class="dwt_author">Greene, H. G.; Exon, N. F.</p> <p class="dwt_publisher"></p> <p class="publishDate">1988-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">190</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.usgs.gov/of/2007/1225/"> <span id="translatedtitle">Digital Data for <span class="hlt">Volcano</span> Hazards at Newberry <span class="hlt">Volcano</span>, Oregon</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Newberry <span class="hlt">volcano</span> is a broad shield <span class="hlt">volcano</span> <span class="hlt">located</span> in central Oregon, the product of thousands of eruptions, beginning about 600,000 years ago. At least 25 vents on the flanks and summit have been active during the past 10,000 years. The most recent eruption 1,300 years ago produced the Big Obsidian Flow. Thus, the <span class="hlt">volcano</span>'s long history and recent activity indicate that Newberry will erupt in the future. Newberry Crater, a volcanic depression or caldera has been the focus of Newberry's volcanic activity for at least the past 10,000 years. Newberry National Volcanic Monument, which is managed by the U.S. Forest Service, includes the caldera and extends to the Deschutes River. Newberry <span class="hlt">volcano</span> is quiet. Local earthquake activity (seismicity) has been trifling throughout historic time. Subterranean heat is still present, as indicated by hot springs in the caldera and high temperatures encountered during exploratory drilling for geothermal energy. The report USGS Open-File Report 97-513 (Sherrod and others, 1997) describes the kinds of hazardous geologic events that might occur in the future at Newberry <span class="hlt">volcano</span>. A hazard-zonation map is included to show the areas that will most likely be affected by renewed eruptions. When Newberry <span class="hlt">volcano</span> becomes restless, the eruptive scenarios described herein can inform planners, emergency response personnel, and citizens about the kinds and sizes of events to expect. The geographic information system (GIS) <span class="hlt">volcano</span> hazard data layers used to produce the Newberry <span class="hlt">volcano</span> hazard map in USGS Open-File Report 97-513 are included in this data set. Scientists at the USGS Cascades <span class="hlt">Volcano</span> Observatory created a GIS data layer to depict zones subject to the effects of an explosive pyroclastic eruption (tephra fallout, pyroclastic flows, and ballistics), lava flows, volcanic gasses, and lahars/floods in Paulina Creek. A separate GIS data layer depicts drill holes on the flanks of Newberry <span class="hlt">Volcano</span> that were used to estimate the probability of coverage by future lava flows.</p> <div class="credits"> <p class="dwt_author">Schilling, S. P.; Doelger, S.; Sherrod, D. R.; Mastin, L. G.; Scott, W. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">191</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=ADA547897"> <span id="translatedtitle">Common <span class="hlt">Submarine</span> Radio Room.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">The CSRR program represents a paradigm shift in the way radio room equipment is procured in the <span class="hlt">submarine</span> fleet. This program is managed under PEO C4I by SPAWAR PMW 770. This thesis examines the cost, schedule, and performance parameters of the CSRR progr...</p> <div class="credits"> <p class="dwt_author">S. S. Roderick</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">192</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=Ship&pg=6&id=EJ659984"> <span id="translatedtitle">Making a <span class="hlt">Submarine</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">Describes Archimedes principle and why a ship sinks when it gets a hole in it. Suggests an activity for teaching the concept of density and water displacement through the construction of a simple <span class="hlt">submarine</span>. Includes materials and procedures for this activity. (KHR)</p> <div class="credits"> <p class="dwt_author">Cornacchia, Deborah J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">193</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/836824"> <span id="translatedtitle">On Helicopters and <span class="hlt">Submarines</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Bernoulli vs. Archimedes - Whenever you see a movie that's got a vehicle that's part helicopter and part <span class="hlt">submarine</span>, you know you're in for a real treat. What could be cooler? One second, the hero's being pursued by some fighter jets piloted by some nasty dudes with bad haircuts, dodging air-to-air missiles and exchanging witty repartee over the radio with</p> <div class="credits"> <p class="dwt_author">Marshall T. Rose</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">194</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009yysu.rept.....G"> <span id="translatedtitle">Yellow, Yellow <span class="hlt">submarin</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The recollections reports on a trip by author to Severodvinsk on the White Sea border (in the Russian Federation), where one of the Buroes and the Soviet atomic <span class="hlt">submarins</span> Factory was placed. The factory and the buroe is placed there till present. A biography of one of the constructors is given.</p> <div class="credits"> <p class="dwt_author">Gaina, Alex</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">195</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2000AREPS..28..539B"> <span id="translatedtitle">Spreading <span class="hlt">Volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">As <span class="hlt">volcanoes</span> grow, they become ever heavier. Unlike mountains exhumed by erosion of rocks that generally were lithified at depth, <span class="hlt">volcanoes</span> typically are built of poorly consolidated rocks that may be further weakened by hydrothermal alteration. The substrates upon which <span class="hlt">volcanoes</span> rest, moreover, are often sediments lithified by no more than the weight of the volcanic overburden. It is not surprising, therefore, that volcanic deformation includes-and in the long term is often dominated by-spreading motions that translate subsidence near volcanic summits to outward horizontal displacements around the flanks and peripheries. We review examples of volcanic spreading and go on to derive approximate expressions for the time <span class="hlt">volcanoes</span> require to deform by spreading on weak substrates. We also demonstrate that shear stresses that drive low-angle thrust faulting from beneath volcanic constructs have maxima at volcanic peripheries, just where such faults are seen to emerge. Finally, we establish a theoretical basis for experimentally derived scalings that delineate <span class="hlt">volcanoes</span> that spread from those that do not.</p> <div class="credits"> <p class="dwt_author">Borgia, Andrea; Delaney, Paul T.; Denlinger, Roger P.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">196</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.kineticcity.com/controlcar/activity.php?act=2&virus=warper"> <span id="translatedtitle"><span class="hlt">Volcano</span> Baseball</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">In this game, learners are <span class="hlt">volcanoes</span> that must complete several steps to erupt. Starting at home plate, learners draw cards until they have enough points to move to first base. This process repeats for each learner at each base, and each base demonstrates a different process in a <span class="hlt">volcano</span>'s eruption. The first learner to make it back to home plate erupts and is the winner. This is a good introduction to <span class="hlt">volcanoes</span>. When learners set up a free account at Kinetic City, they can answer bonus questions at the end of the activity as a quick assessment. As a larger assessment, learners can complete the Smart Attack game after they've completed several activities.</p> <div class="credits"> <p class="dwt_author">Science, American A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">197</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005APS..DFD.KQ002B"> <span id="translatedtitle">Experimental Measurements of a Model <span class="hlt">Submarine</span> Wake</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">High resolution stereo-PIV measurements were made over ten body lengths downstream of a 1/18^th scale <span class="hlt">submarine</span> model in the Deep Water Tow Basin at NSWCCD. The <span class="hlt">submarine</span> model is an unclassified generic <span class="hlt">submarine</span> shape (ONR Body-1) composed of an axisymmetric body, four stern appendages (control surfaces) and a propeller. This body is 5.8 m long, 0.49 m in diameter. Block gages on the struts measured streamwise force on the body and provided loading details for setting propeller speed. The model was towed through a stationary laser sheet oriented perpendicular to the tow direction to obtain three-dimensional velocity fields. The objective of the study was to quantify the <span class="hlt">submarine</span> wake and rate of decay of the coherent vortices. These data will be used in conjunction with measurements obtained on a model towed array to validate computational models for array shape and dynamics. Results with and without the propeller will be presented. Approximately 40 instantaneous vector fields were obtained for each <span class="hlt">location</span>. Mean and fluctuating streamwise and cross-stream velocities and vorticity were computed.</p> <div class="credits"> <p class="dwt_author">Bretall, Damien; Furey, Deborah; Cipolla, Kimberly</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">198</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010JVGR..194..107R"> <span id="translatedtitle">Type of <span class="hlt">volcanoes</span> hosting the massive sulfide deposits of the Iberian Pyrite Belt</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Volcanic Sedimentary Complex (VSC) of the Iberian Pyrite Belt (IPB) in southern Portugal and Spain, comprises an Upper Devonian to Lower Carboniferous <span class="hlt">submarine</span> succession with a variety of felsic volcanic lithofacies. The architecture of the felsic volcanic centres includes felsic lavas/domes, pyroclastic units, intrusions and minor mafic units that define lava-cryptodome-pumice cone <span class="hlt">volcanoes</span>. The diversity of volcanic lithofacies recognized in different areas of the IPB mainly reflects variations in proximity to source, but also differences in the eruption style. The IPB <span class="hlt">volcanoes</span> are intrabasinal, range in length from 2 km to > 8 km and their thickest sections vary from ˜ 400 m to > 800 m. These <span class="hlt">volcanoes</span> are dominated by felsic lavas/domes that occur at several stratigraphic positions within the volcanic centre, however the pyroclastic units are also abundant and are spatially related to the lavas/domes. The intrusions are minor, and define cryptodomes and partly-extrusive cryptodomes. The hydrothermal systems that formed the Neves Corvo and Lousal massive sulfide ore deposits are associated with effusive units of felsic volcanic centres. At Neves Corvo, the massive sulfide orebodies are associated to rhyolitic lavas that overlie relatively thick fiamme-rich pyroclastic unit. In several other <span class="hlt">locations</span> within the belt, pyroclastic units contain sulfide clasts that may have been derived from yet to be discovered coeval massive sulfide deposits at or below the sea floor, which enhances the exploration potential of these pyroclastic units and demonstrates the need for volcanic facies analysis in exploration.</p> <div class="credits"> <p class="dwt_author">Rosa, Carlos J. P.; McPhie, Jocelyn; Relvas, Jorge M. R. S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">199</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19940029486&hterms=pumice&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dpumice"> <span id="translatedtitle">Mount Rainier active cascade <span class="hlt">volcano</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Mount Rainier is one of about two dozen active or recently active <span class="hlt">volcanoes</span> in the Cascade Range, an arc of <span class="hlt">volcanoes</span> in the northwestern United States and Canada. The <span class="hlt">volcano</span> is <span class="hlt">located</span> about 35 kilometers southeast of the Seattle-Tacoma metropolitan area, which has a population of more than 2.5 million. This metropolitan area is the high technology industrial center of the Pacific Northwest and one of the commercial aircraft manufacturing centers of the United States. The rivers draining the <span class="hlt">volcano</span> empty into Puget Sound, which has two major shipping ports, and into the Columbia River, a major shipping lane and home to approximately a million people in southwestern Washington and northwestern Oregon. Mount Rainier is an active <span class="hlt">volcano</span>. It last erupted approximately 150 years ago, and numerous large floods and debris flows have been generated on its slopes during this century. More than 100,000 people live on the extensive mudflow deposits that have filled the rivers and valleys draining the <span class="hlt">volcano</span> during the past 10,000 years. A major volcanic eruption or debris flow could kill thousands of residents and cripple the economy of the Pacific Northwest. Despite the potential for such danger, Mount Rainier has received little study. Most of the geologic work on Mount Rainier was done more than two decades ago. Fundamental topics such as the development, history, and stability of the <span class="hlt">volcano</span> are poorly understood.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">200</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009EGUGA..11.2283Y"> <span id="translatedtitle">Regularly spaced <span class="hlt">submarine</span> rhyolitic-calderas on the Tokara volcanic ridge, northern Ryukyu arc, Japan</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The southern part of the Kyushu Island where is the northern end of the 1300 km long Ryukyu arc, has some huge calderas, Aira and Kikai calderas. These calderas are considered to be formed by the Quaternary super-eruptions. <span class="hlt">Submarine</span> calderas, Kuchinoshima,Takarashima and Amami calderas, which are of the same size as the Aira caldera,on the Tokara volcanic ridge that is the southern extension of the Kyushu Island, have been proposed on the basis of the bathymetric data. To confirm whether the caldera-like topographic expressions are of volcanic or tectonic in origin, we carried out approximately 70 dredge samplings during six ocean research cruises (KT00-15, KT07-2, KT07-21, NAG252, NAG267, and NAG274). Collected rock samples both from the on-land and seafloor of the Tokara Islands were compared to define the genetic correlations. The weathering condition of the volcanic rocks in the Tokara Islands is different from the main land of Japan due to its hot and humid subtropical weather. Therefore, some samples are probably highly ferrallitizated by the weather condition. Indeed volcanic rocks with high loss on ignition value are relatively poorer in K2O and SiO2 and richer in Al2O3, Fe2O3, TiO2 compared with the low LOI value rocks. The LOI values could be an available threshold for excluding unreliable sample data. Each <span class="hlt">volcano</span> shows individual trend on the K2O vs. SiO2 diagram. We revealed that there is obvious regional variation in their magma chemistry. Not only dense rocks but also highly vesiculated rhyolite samples collected from the seafloor are plotted on the same volcanic trends. The volcanic rocks recovered from the seafloor predominate in acidic rocks, rhyolite and dacite, rather than andesite. The rhyolitic pumice that are highly calcified by biological activity, were also found on the <span class="hlt">submarine</span> plateaus that are <span class="hlt">located</span> around the edge of <span class="hlt">submarine</span> calderas at about 200 m depth. These samples imply that the <span class="hlt">submarine</span> plateaus are not simply erosional remnant, but a product of caldera forming eruptions. The other <span class="hlt">submarine</span> acidic rocks preserve fresh volcanic glass and are considered to be young. The measured K-Ar ages for the two representative acidic rocks, porphyritic rhyolite and aphyric dacite are young (0.6 Ma and < 0.20 Ma). Therefore, the rhyolitic volcanism could be active on the present <span class="hlt">submarine</span> volcanic front of the Tokara volcanic ridge. Our investigations support the idea that the <span class="hlt">submarine</span> caldera-like topographies were produced by the Quaternary super-eruptions. If this is valid, the five huge calderas, including well studied Aira and Kikai calderas, align regularly at approximately 100 km interval from the southern Kyushu Island to the central part of the Ryukyu arc.</p> <div class="credits"> <p class="dwt_author">Yokose, H.; Sato, H.; Fujimoto, Y.; Mirabueno, M.; Kobayashi, T.; Akimoto, K.; Yoshimura, H.; Morii, Y.; Yamawaki, N.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-04-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_9");' href="#" title="Previous Page"> <img 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href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_12");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">201</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=10512&hterms=Tectonic+Plates&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3D%2522Tectonic%2BPlates%2522"> <span id="translatedtitle">Klyuchevskaya <span class="hlt">Volcano</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The Klyuchevskaya <span class="hlt">Volcano</span> 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 <span class="hlt">volcano</span>'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 <span class="hlt">volcano</span> 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 <span class="hlt">volcano</span> 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> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">202</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011JGRB..116.2102L"> <span id="translatedtitle">Active hydrothermal discharge on the <span class="hlt">submarine</span> Aeolian Arc</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In November 2007 we conducted a water column and seafloor mapping study of the <span class="hlt">submarine</span> <span class="hlt">volcanoes</span> of the Aeolian Arc in the southern Tyrrhenian Sea aboard the R/V Urania. On 26 conductivity-temperature-depth casts and tows we measured temperature, conductivity, pressure, and light scattering and also collected discrete samples for helium isotopes, methane, and pH. The 3He/4He isotope ratio, an unambiguous indicator of hydrothermal input, showed a clear excess above background at 6 of the 10 <span class="hlt">submarine</span> <span class="hlt">volcanoes</span> surveyed. Marsili seamount had the highest anomaly, where the 3He/4He ratio reached a ?3He value of 23% at 610 m depth compared with background values of ˜5%. Smaller but distinct ?3He anomalies occurred over Palinuro, Enarete, Eolo, Sisifo, and Secca del Capo. Although hydrothermal emissions are known to occur offshore of some Aeolian subaerial <span class="hlt">volcanoes</span>, and hydrothermal deposits have been sampled throughout the arc, our results are the first to confirm active discharge on Marsili, Enarete, Eolo, Sisifo, and Secca del Capo. Samples collected over Lametini, Filicudi North, Alicudi North, and Alcione had ?3He near the regional background values, suggesting either absence of, or very weak, hydrothermal activity on these seamounts. Hydrocasts between the <span class="hlt">volcanoes</span> revealed a consistent ?3He maximum between 11% and 13% at 2000 m depth throughout the SE Tyrrhenian Sea. The <span class="hlt">volcanoes</span> of the Aeolian arc and the Marsili back arc, all <1000 m deep, cannot contribute directly to this maximum. This deep 3He excess may be a remnant of tritium decay or may have been produced by an unknown deep hydrothermal source.</p> <div class="credits"> <p class="dwt_author">Lupton, John; de Ronde, Cornel; Sprovieri, Mario; Baker, Edward T.; Bruno, Pier Paolo; Italiano, Franco; Walker, Sharon; Faure, Kevin; Leybourne, Matthew; Britten, Karen; Greene, Ronald</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">203</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFM.T31B2584C"> <span id="translatedtitle">Active <span class="hlt">Submarine</span> Hotspot Volcanism on the Kerguelen Plateau</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Heard and McDonald Islands on the Kerguelen Plateau, southern Indian Ocean, are active intraplate hotspot <span class="hlt">volcanoes</span>. Heard Island is approximately 43 km long, and encompasses an area of approximately 368 square km. It is dominated by Big Ben, a roughly circular <span class="hlt">volcano</span> with a base diameter of 18-20 km, and a maximum elevation of 2745 m. The McDonald Islands have an area of approximately 2.5 square km. Due to a lack of human habitation and no geoscientific monitoring, and cloud cover precluding satellite remote sensing for geoscientific purposes, the level of volcanic activity of the islands is unknown, but observers on passing ships frequently report eruptions, including molten lava, volcanic plumes, and tephra, and active fumaroles. Bathymetric, seismic reflection, magnetic, and gravity data acquired around Heard and McDonald Islands suggest that <span class="hlt">submarine</span> magmatism affects a broad region of surrounding Kerguelen Plateau seafloor. In this region, we have identified six distinct fields of sea knolls that we interpret to be volcanic in origin. Individual fields contain from approximately 14 to approximately 140 sea knolls, and are not uniformly distributed around Heard and McDonald Islands. Given that Heard and McDonald Islands are volcanically active, it is likely that at least some of the interpreted <span class="hlt">submarine</span> <span class="hlt">volcanoes</span> are active and drive hydrothermal circulation.</p> <div class="credits"> <p class="dwt_author">Coffin, M. F.; Leser, T. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">204</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006HMR....60..257W"> <span id="translatedtitle">A new species of Copepoda Harpacticoida, Xylora calyptogenae spec. n., with a carnivorous life-style from a hydrothermally active <span class="hlt">submarine</span> <span class="hlt">volcano</span> in the New Ireland Fore-Arc system (Papua New Guinea) with notes on the systematics of the Donsiellinae Lang, 1948</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A new species of harpacticoid copepods, Xylora calyptogenae spec. n., from Edison Seamount, a hydrothermally active <span class="hlt">submarine</span> <span class="hlt">volcano</span> in the New Ireland Fore-Arc system (Papua New Guinea) is described. The new species belongs to the Donsiellinae Lang, 1944, a highly specialised taxon, the members of which have previously been encountered only in association with decaying wood and/or wood-boring isopods. A closer relationship of the Donsiellinae with the Pseudotachidiidae Lang, 1936, can be stated on the basis of characteristics concerning the setation and/or segmentation of A1, A2, Mxl, Mxp, the shape of the female P5, anal somite, sexual dimorphisms on P2 and P3 and missing caudal seta I. Within the Pseudotachidiidae, the Donsiellinae again can be well characterized, e.g. by the setation and segmentation of A2, Mxl, swimming-legs, the shape of P1, female P5, male P2, sexual dimorphism and male P5. The Donsiellinae share some apomorphies with the pseudotachidiid subtaxon Paranannopinae Por, 1986: setation/segmentation of Mx, P1, A1. X. calyptogenae spec. n. is more closely related to Xylora bathyalis Hicks 1988 living in the deep sea wood substrata in New Zealand waters. Some traits of the evolutionary history of the Donsiellinae become evident, probably starting from the more primitive deep sea taxa X .calyptogenae spec. n., which lives in the hydrothermal seafloor in the absence of decaying wood, and X. bathyalis, which is found in decaying wood but not necessarily associated with the wood-boring isopod Limnoria Leach, 1814, towards the more advanced genera such as Donsiella Stephensen, 1936, which invades shallow waters and, further, clings to Limnoria, forming a close and, for the copepod, probably obligatory association. The specialised mouthparts of X. calyptogenae spec. n. seem to facilitate the grabbing and fixing of larger and/or active food items. This is confirmed by the presence of a large prey organism, presumably a copepod, consumed either alive or dead, in the gut of one of the available specimens. This morphology of the mouthparts is also shared by the closely related X. bathyalis.</p> <div class="credits"> <p class="dwt_author">Willen, Elke</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">205</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/14901934"> <span id="translatedtitle">Flushing <span class="hlt">submarine</span> canyons</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The continental slope is a steep, narrow fringe separating the coastal zone from the deep ocean. During low sea-level stands, slides and dense, sediment-laden flows erode the outer continental shelf and the continental slope, leading to the formation of <span class="hlt">submarine</span> canyons that funnel large volumes of sediment and organic matter from shallow regions to the deep ocean1. During high sea-level</p> <div class="credits"> <p class="dwt_author">Miquel Canals; Pere Puig; Xavier Durrieu de Madron; Serge Heussner; Albert Palanques; Joan Fabres</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">206</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/41982246"> <span id="translatedtitle"><span class="hlt">Submarine</span> intraplate volcanism in the South Pacific: Geological setting and petrology of the Society and the Austral regions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The southeastern prolongations of the Society and Austral islands volcanic chains are terminated by several recent <span class="hlt">submarine</span> <span class="hlt">volcanoes</span> (300-3800 m in height) built on irregularly shaped crustal swells or bulges (3600-3950 m in depth). The crustal swells (about 100 km in width) is bounded by deeper abyssal hill regions (>4000 m in depth) where old <span class="hlt">volcanoes</span> with thick Fe-Mn coatings</p> <div class="credits"> <p class="dwt_author">Roger Hekinian; Daniel Bideau; Peter Stoffers; Jean Louis Cheminee; Richard Muhe; Doris Puteanus; Nicolas Binard</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">207</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.usgs.gov/of/2001/0395/@noteDOCUMENT#texthttp://pubs.usgs.gov/of/2001/0395/pdf/of2001-0395.pdf@notePLATE#texthttp://pubs.usgs.gov/of/2001/0395/pdf/of2001-0395_plate1.pdf"> <span id="translatedtitle">Lahar-hazard zonation for San Miguel <span class="hlt">volcano</span>, El Salvador</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">San Miguel <span class="hlt">volcano</span>, also known as Chaparrastique, is one of many <span class="hlt">volcanoes</span> along the volcanic arc in El Salvador. The <span class="hlt">volcano</span>, <span class="hlt">located</span> in the eastern part of the country, rises to an altitude of about 2130 meters and towers above the communities of San Miguel, El Transito, San Rafael Oriente, and San Jorge. In addition to the larger communities that surround the <span class="hlt">volcano</span>, several smaller communities and coffee plantations are <span class="hlt">located</span> on or around the flanks of the <span class="hlt">volcano</span>, and the PanAmerican and coastal highways cross the lowermost northern and southern flanks of the <span class="hlt">volcano</span>. The population density around San Miguel <span class="hlt">volcano</span> coupled with the proximity of major transportation routes increases the risk that even small <span class="hlt">volcano</span>-related events, like landslides or eruptions, may have significant impact on people and infrastructure. San Miguel <span class="hlt">volcano</span> is one of the most active <span class="hlt">volcanoes</span> in El Salvador; it has erupted at least 29 times since 1699. Historical eruptions of the <span class="hlt">volcano</span> consisted mainly of relatively quiescent emplacement of lava flows or minor explosions that generated modest tephra falls (erupted fragments of microscopic ash to meter sized blocks that are dispersed into the atmosphere and fall to the ground). Little is known, however, about prehistoric eruptions of the <span class="hlt">volcano</span>. Chemical analyses of prehistoric lava flows and thin tephra falls from San Miguel <span class="hlt">volcano</span> indicate that the <span class="hlt">volcano</span> is composed dominantly of basalt (rock having silica content</p> <div class="credits"> <p class="dwt_author">Major, J. J.; Schilling, S. P.; Pullinger, C. R.; Escobar, C. D.; Chesner, C. A.; Howell, M. M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">208</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1986EOSTr..67...74M"> <span id="translatedtitle">Investigation of Surtsey <span class="hlt">Volcano</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The volcanic island of Surtsey, Iceland, was built during the period November 1963 to June 1967 and is one of the few oceanic volcanic islands that has formed and survived in recent times. New stimulus to geologic work on the island was provided in 1979 by completion of a 181-m-deep hole that was drilled to investigate the structure of the <span class="hlt">volcano</span> and the active hydrothermal system below.During August 1985 an international group of researchers undertook a series of geologic and biologic investigations on the island. This work was facilitated by new aerial photographs taken by the Icelandic Geodetic Survey and a new bathymetric map of the Surtsy region made by the Icelandic Hydrographic Service (both in Reykjavik). Ground surveying of markers appearing in the photographs will permit a major revision of the to pographic map of the island (scale 1:5000). The new bathymetry defines the extent of continuing erosion of three volcanic vents, two of which formed short-lived islands during the Surtsey eruptive episode. Since 1967, when the first bathymetry of these <span class="hlt">submarine</span> features was made, the summitt errace of Syrtlingur has been reduced from 23 to 32 m below sea level; that of Jolnir, from 15 to 37 m; and that of Surtla, from 32 t o 46 m.</p> <div class="credits"> <p class="dwt_author">Moore, James G.; Jakobsson, Sveinn P.; Norrman, John O.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">209</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70016939"> <span id="translatedtitle">Underwater observations of active lava flows from Kilauea <span class="hlt">volcano</span>, Hawaii</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Underwater observation of active <span class="hlt">submarine</span> lava flows from Kilauea <span class="hlt">volcano</span>, Hawaii, in March-June 1989 revealed both pillow lava and highly channelized lava streams flowing down a steep and unconsolidated lava delta. The channelized streams were 0.7-1.5 m across and moved at rates of 1-3 m/s. The estimated flux of a stream was 0.7 m3/s. Jets of hydrothermal water and gas bubbles were associated with the volcanic activity. The rapidly moving channelized lava streams represent a previously undescribed aspect of <span class="hlt">submarine</span> volcanism. -Author</p> <div class="credits"> <p class="dwt_author">Tribble, G. W.</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">210</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013BVol...75..777S"> <span id="translatedtitle">Earthquake occurrence reveals magma ascent beneath <span class="hlt">volcanoes</span> and seamounts in the Banda region</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Characteristic seismicity patterns beneath the volcanic arcs of the Banda region, SE Asia, suggest that magmatic processes have recently occurred beneath <span class="hlt">submarine</span> portions of the arcs, forming yet-unrecognised <span class="hlt">submarine</span> <span class="hlt">volcanoes</span>. We have found that almost 50 % of earthquakes spatially associated with the Banda and Ambon volcanic arcs occurred in sequences with epicenters often concentrated in a small area and foci distributed in vertically elongated domains. The most pronounced occurrence of such earthquake series and swarms was observed in the area of the Manipa <span class="hlt">submarine</span> basin (latitude 3.75°S, longitude 127.5°E, ESE of Buru Island), the remarkable morphology of which resembles a huge caldera (60 km in diameter) with a distinct cone seamount in its center, reaching almost 3000 m above seafloor. Another candidate for an unrecognised <span class="hlt">submarine</span> <span class="hlt">volcano</span> is an area between <span class="hlt">volcanoes</span> Banda Api and Manuk, with a huge 1973/74 earthquake swarm. We assume that such a specific occurrence of earthquakes is induced by magma ascent and migration along faults above the subducting slab, with magma possibly occasionally reaching the sea floor. Utilization of teleseismic data can thus reveal activation of plumbing systems of <span class="hlt">submarine</span> <span class="hlt">volcanoes</span>, and highlight areas with the potential of near-future volcanic events.</p> <div class="credits"> <p class="dwt_author">Špi?ák, Aleš; Kuna, Václav; Van?k, Ji?í</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">211</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012EGUGA..14.5928F"> <span id="translatedtitle"><span class="hlt">Submarine</span> landslides in Spitsbergen fjords</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Fjords are areas that can be exposed to repeated <span class="hlt">submarine</span> mass wasting, and more than 50% of the depositional sequences can be reworked occasionally. The largest and most frequent slope failures occur typically in relation to the advance and retreat of grounded ice. However, also areas not directly affected by ice can be exposed to slope failure. We provide an overview of mass-transport deposits (MTDs) from the Isfjorden fjord system, the largest fjord system on Spitsbergen. We discuss pre-conditioning factors, trigger mechanisms and the potential of MTDs as indicators for the activity of tidewater and terrestrial glaciers. Slides, slumps, debris-flow deposits and turbidites have been observed. We distinguish three 'types' of MTDs: 1) 'Glacigenic MTDs', including muddy debris-flow lobes, as well as thin sandy MTDs deposited in front of or beneath glaciers; 2) 'Fluvial MTDs', including sandy turbidites and other MTDs originating from slope failures beyond river mouths; 3) 'Other MTDs', i.e. deposits related to failures on slopes that are neither supplied with sediments from glaciers nor from rivers. Such deposits include sediment lobes (debris flows or slumps) and slides. The available data indicate that mass wasting in the Isfjorden area commenced shortly after the deglaciation of the mouth of the trunk fjord around 14,100 cal. years BP. The most frequent pre-conditioning factors and trigger mechanisms are probably high sediment supply and earthquakes related to isostatic adjustments. However, marked changes in the slope gradient (related to bedrock or moraine ridges) also affect the stability of the fronts of tidewater glaciers and the positions of grounding lines, thus influencing the <span class="hlt">locations</span> of sediment sources and, in consequence, the distribution of glacigenic MTDs. In addition to providing information about the dynamics of marine-terminating glaciers, <span class="hlt">submarine</span> MTDs occasionally also provide information about the dynamics of terrestrial glaciers during the Holocene.</p> <div class="credits"> <p class="dwt_author">Forwick, M.; Vorren, T. O.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">212</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/27100668"> <span id="translatedtitle"><span class="hlt">Location</span>, <span class="hlt">Location</span>, <span class="hlt">Location</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In this article, the accuracy estimation of radio <span class="hlt">location</span> techniques throughout ray-tracing-based propagation models has been discussed. Assuming as a reference scenario a 16-building Manhattan environment, some numerical results for 2-D <span class="hlt">location</span> accuracy of some <span class="hlt">location</span> techniques have been presented and discussed. It has clearly been shown that a site-specific simulation tool can easily account for NLOS conditions and multipath</p> <div class="credits"> <p class="dwt_author">M. Porretta; P. Nepa; G. Manara; F. Giannetti</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">213</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6250610"> <span id="translatedtitle"><span class="hlt">Volcanoes</span> generate devastating waves</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Although volcanic eruptions can cause many frightening phenomena, it is often the power of the sea that causes many <span class="hlt">volcano</span>-related deaths. This destruction comes from tsunamis (huge <span class="hlt">volcano</span>-generated waves). Roughly one-fourth of the deaths occurring during volcanic eruptions have been the result of tsunamis. Moreover, a tsunami can transmit the <span class="hlt">volcano</span>'s energy to areas well outside the reach of the eruption itself. Some historic records are reviewed. Refined historical data are increasingly useful in predicting future events. The U.S. National Geophysical Data Center/World Data Center A for Solid Earth Geophysics has developed data bases to further tsunami research. These sets of data include marigrams (tide gage records), a wave-damage slide set, digital source data, descriptive material, and a tsunami wall map. A digital file contains information on methods of tsunami generation, <span class="hlt">location</span>, and magnitude of generating earthquakes, tsunami size, event validity, and references. The data can be used to describe areas mot likely to generate tsunamis and the <span class="hlt">locations</span> along shores that experience amplified effects from tsunamis.</p> <div class="credits"> <p class="dwt_author">Lockridge, P. (National Geophysical Data Center, Boulder, CO (USA))</p> <p class="dwt_publisher"></p> <p class="publishDate">1988-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">214</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/14801504"> <span id="translatedtitle">Hot spot and trench <span class="hlt">volcano</span> separations</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">WE suggest that the distribution of separations between trench <span class="hlt">volcanoes</span> <span class="hlt">located</span> along subduction zones reflects the depth of partial melting, and that the separation distribution for hot spot <span class="hlt">volcanoes</span> near spreading centres provides a measure of the depth of mantle convection cells.</p> <div class="credits"> <p class="dwt_author">R. E. Lingenfelter; G. Schubert</p> <p class="dwt_publisher"></p> <p class="publishDate">1974-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">215</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/49986201"> <span id="translatedtitle">MESMA: AIP system for <span class="hlt">submarines</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">MESMA (autonomous <span class="hlt">submarine</span> energy module) is an AIP system (air independent propulsion) which has been developed in order to equip <span class="hlt">submarine</span> vehicles. Good results were obtained during the trials carried out on a primary loop prototype made the French Directorate for Naval Construction (DCN) and Bertin Company (owner of patents) who worked together to study a MESMA version for conventional</p> <div class="credits"> <p class="dwt_author">P. Kerros; C. Inizan; D. Grousset</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">216</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40778480"> <span id="translatedtitle">Using multiple geochemical tracers to characterize the hydrogeology of the <span class="hlt">submarine</span> spring off Crescent Beach, Florida</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">A spectacular <span class="hlt">submarine</span> spring is <span class="hlt">located</span> about 4 km east of Crescent Beach, FL, in the Atlantic Ocean. The single vent feature of Crescent Beach Spring provides a unique opportunity to examine onshore–offshore hydrogeologic processes, as well as point source <span class="hlt">submarine</span> ground water discharge. The Floridan aquifer system in northeastern Florida consists of Tertiary interspersed limestone and dolomite strata. Impermeable</p> <div class="credits"> <p class="dwt_author">P. W Swarzenski; C. D Reich; R. M Spechler; J. L Kindinger; W. S Moore</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">217</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/11876194"> <span id="translatedtitle">Current <span class="hlt">submarine</span> atmosphere control technology.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Air purification in <span class="hlt">submarines</span> was introduced towards the end of World War II and was limited to the use of soda lime for the removal of carbon dioxide and oxygen candles for the regeneration of oxygen. The next major advances came with the advent of nuclear-powered <span class="hlt">submarines</span>. These included the development of regenerative and, sometimes, energy-intensive processes for comprehensive atmosphere revitalization. With the present development of conventional <span class="hlt">submarines</span> using air-independent propulsion there is a requirement for air purification similar to that of the nuclear-powered <span class="hlt">submarines</span> but it is constrained by limited power and space. Some progress has been made in the development of new technology and the adoption of air purification equipment used in the nuclear-powered <span class="hlt">submarines</span> for this application. PMID:11876194</p> <div class="credits"> <p class="dwt_author">Mazurek, W</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">218</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/51752329"> <span id="translatedtitle"><span class="hlt">Submarine</span> Structure and Stratigraphy of the South Kona Slump, Hawaii: Results from the MBARI 2001 Hawaii Expedition</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">As part of the MBARI 2001 Hawaii Expedition on board the R\\/V Western Flyer, the ROV Tiburon was used to carry out several highly successful dives upon the little studied <span class="hlt">submarine</span> South Kona slump, southwest Mauna Loa, Hawaii, offering a rare opportunity to look inside the broken flank of Mauna Loa <span class="hlt">volcano</span>. Four dives transected a scarp marking the southern</p> <div class="credits"> <p class="dwt_author">J. K. Morgan; D. A. Clague; A. S. Davis</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">219</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2001AGUFM.V12B0970R"> <span id="translatedtitle">Observations on the Origin of <span class="hlt">Submarine</span> Volcanic Cone Morphologies in Hawaii</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Our recent models for the formation of flat-topped and pointed volcanic cones on the <span class="hlt">submarine</span> flanks of the Hawaiian islands were based on 30 kHz multibeam bathymetry and backscatter data and the few existing samples [Clague et al., Bull. Volcanol. 62, 214-233, 2000]. During MBARI's Hawaii expedition in April-May 2001, we used the ROV TIBURON to further investigate the origins of volcanic cones. Pointed cones have steep, symmetrical, smooth slopes with no discernible summit platform. We proposed that these were monogenetic cones constructed of a uniform type of fragmental volcanic products in the manner of cinder cones on land; major differences are that <span class="hlt">submarine</span> pointed cones are taller and do not have summit craters. Observations from dives on three such cones on the NW flank of Ni`ihau showed that the smooth acoustic character of the slopes cannot be attributed either to sediment cover or to the specific nature of volcanic products on the cones' surfaces (e.g., volcaniclastics vs. talus vs. pillow lava), but instead to a uniform distribution of these products. One of the cones is partly dissected and eroded, exposing bedded volcaniclastics in both interior and exterior, but near the summit its surface is mantled by pillow lava. The other two are <span class="hlt">located</span> 600m apart and are composed of geochemically similar hawaiites, suggesting that they represent two vents from the same eruption. These observations are consistent with our proposal that these pointed cones were constructed by vigorous eruption of fragmental ejecta, and this gives them their steep, pointed shape. The pillow lava is a thin veneer extruded at lower effusion rate during the waning stage of eruptions. New samples from these three pointed cones are vesicular hawaiite similar to Ni'ihau's subaerial postshield alkalic lavas, and confirm that pointed cones form by eruptions of gas-rich alkalic lavas. Flat-topped volcanic cones are found on the tholeiitic <span class="hlt">submarine</span> rift zones of all mature Hawaiian <span class="hlt">volcanoes</span>, and are also abundant on the <span class="hlt">submarine</span> flank of Ni`ihau. They have the form of truncated cones. We modeled them as monogenetic constructions formed by an inflating and overflowing lava pond during protracted, steady eruption of gas-poor, low-viscosity lava. Previous dive observations on flat-topped cones at Mahukona and Kohala showed that the outer slopes are covered by pillow lava flows (and talus), consistent with overflows from a lava pond, but observations on the flat tops were thwarted by heavy sediment cover. The recent TIBURON dives investigated five flat-topped cones on Ni`ihau. As before, elongated pillow lavas were observed on the outer slopes. On the flat tops, the lava flow forms protruding through the sediment were primarily hackly sheet flows, folded sheets, tumuli (which form on inflated sheet flows), and lobate lavas. <span class="hlt">Submarine</span> hackly sheet flows indicate unusually fast-moving, well-insulated lava. Existence of these flow forms on a low-grade slope is consistent with crust forming on an actively circulating lava pond, and suggests that the crust forms over large areas of the pond at once, rather than gradually accumulating at the edges as the cone grows. The lobate flows may represent lava extruded through cracks in the crust. The flat-topped cones on Ni`ihau are confirmed to be <span class="hlt">submarine</span> equivalents of the rejuvenated stage Kiekie Volcanics on the island. The new samples have low vesicularity, supporting the model of flat-topped cones as sustained eruptions of gas-poor, low-viscosity lava.</p> <div class="credits"> <p class="dwt_author">Reynolds, J. R.; Clague, D. A.; Hon, K.; Dixon, J. E.; Cousens, B. L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">220</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004AGUFM.V44A..02T"> <span id="translatedtitle">Shrimp Populations on Northwest Rota, an Active <span class="hlt">Volcano</span> of the Mariana Volcanic Arc</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">NW Rota-1 is a <span class="hlt">submarine</span> <span class="hlt">volcano</span> that manifested active volcanic and hydrothermal activity during submersible surveys in March 2004 (see Embley et al.). Substratum on the <span class="hlt">volcano</span> summit (520 m depth) was entirely basalt outcrop or variously-sized ejecta lying near the angle of repose. While no fauna inhabited the rim of the volcanic pit, patches of shrimp were <span class="hlt">located</span> within 25 m and on the nearby summit. Two species are present. Opaepele cf. loihi shows few morphological differences from either a nearby population on Eifuku <span class="hlt">Volcano</span> (see Chadwick et al.) at 1700 m depth or from the type locality in Hawaii. A molecular comparison of COI sequences of 13 specimens found little difference from two Hawaiian sequences. Video observations detail frequent feeding activity using spatulate chelipeds to trim microbial filaments as the cephalothorax sways across the substratum. The second species is an undescribed Alvinocaris. Juveniles of this species appear to form clusters distinct from Opaepele where they also graze on filaments. Sparse adults of Alvinocaris range up to 5.5 cm long and display aggressive behaviour moving through patches of smaller shrimp. Densities of Opaepele were highest on sloping rock walls (over 500 per sq.m.) whereas adult Alvinocaris were more abundant on rubble. This division may reflect food preference: microbial filaments versus polychaetes and meiofauna. Characterization of particulates from these substrata was conducted using visual sorting and stable isotope composition. As Alvinocaris matures, the chelipeds enlarge, enabling a greater predatory capacity. Measurements of Opaepele from digital in situ images reveal a population structure suggesting a recent recruitment. Average size is significantly smaller than the Eifuku population and no egg-bearing females were collected. The disjunct range of this species where it occurs on active <span class="hlt">volcanoes</span> 6000 km apart is puzzling. Further work on intermediate sites and into the reproductive strategy of the species is required.</p> <div class="credits"> <p class="dwt_author">Tunnicliffe, V.; Juniper, S. K.; Limén, H.; Jones, W. J.; Vrijenhoek, R.; Webber, R.; Eerkes-Medrano, D.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-12-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_10");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a 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href="#">11</a> <a style="font-weight: bold;">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_13");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">221</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/1gx48801276w43t0.pdf"> <span id="translatedtitle">Modeling ground deformations of Panarea <span class="hlt">volcano</span> hydrothermal\\/geothermal system (Aeolian Islands, Italy) from GPS data</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Panarea <span class="hlt">volcano</span> (Aeolian Islands, Italy) was considered extinct until November 3, 2002, when a <span class="hlt">submarine</span> gas eruption began\\u000a in the area of the islets of Lisca Bianca, Bottaro, Lisca Nera, Dattilo, and Panarelli, about 2.5 km east of Panarea Island.\\u000a The gas eruption decreased to a state of low degassing by July 2003. Before 2002, the activity of Panarea <span class="hlt">volcano</span> was</p> <div class="credits"> <p class="dwt_author">Alessandra Esposito; Marco Anzidei; Simone Atzori; Roberto Devoti; Guido Giordano; Grazia Pietrantonio</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">222</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://school.discovery.com/lessonplans/programs/understanding-volcanoes/index.html"> <span id="translatedtitle">Understanding <span class="hlt">Volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This lesson plan is part of the DiscoverySchool.com lesson plan library for grades 6-8. It focuses on the three types of <span class="hlt">volcanoes</span>: shield, cinder cone, and composite. Students research each type and then make models of each one to learn the distinctive properties of each type. Included are objectives, materials, procedures, discussion questions, evaluation ideas, suggested readings, and vocabulary. There are videos available to order which complement this lesson, an audio-enhanced vocabulary list, and links to teaching tools for making custom quizzes, worksheets, puzzles and lesson plans.</p> <div class="credits"> <p class="dwt_author">Weisel, Frank</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">223</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dx.doi.org/10.1016/j.epsl.2007.01.030"> <span id="translatedtitle">Massive edifice failure at Aleutian arc <span class="hlt">volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Along the 450-km-long stretch of the Aleutian volcanic arc from Great Sitkin to Kiska Islands, edifice failure and <span class="hlt">submarine</span> debris-avalanche deposition have occurred at seven of ten Quaternary volcanic centers. Reconnaissance geologic studies have identified subaerial evidence for large-scale prehistoric collapse events at five of the centers (Great Sitkin, Kanaga, Tanaga, Gareloi, and Segula). Side-scan sonar data collected in the 1980s by GLORIA surveys reveal a hummocky seafloor fabric north of several islands, notably Great Sitkin, Kanaga, Bobrof, Gareloi, Segula, and Kiska, suggestive of landslide debris. Simrad EM300 multibeam sonar data, acquired in 2005, show that these areas consist of discrete large blocks strewn across the seafloor, supporting the landslide interpretation from the GLORIA data. A debris-avalanche deposit north of Kiska Island (177.6?? E, 52.1?? N) was fully mapped by EM300 multibeam revealing a hummocky surface that extends 40??km from the north flank of the <span class="hlt">volcano</span> and covers an area of ??? 380??km2. A 24-channel seismic reflection profile across the longitudinal axis of the deposit reveals a several hundred-meter-thick chaotic unit that appears to have incised into well-bedded sediment, with only a few tens of meters of surface relief. Edifice failures include thin-skinned, narrow, Stromboli-style collapse as well as Bezymianny-style collapse accompanied by an explosive eruption, but many of the events appear to have been deep-seated, removing much of an edifice and depositing huge amounts of debris on the sea floor. Based on the absence of large pyroclastic sheets on the islands, this latter type of collapse was not accompanied by large eruptions, and may have been driven by gravity failure instead of magmatic injection. Young <span class="hlt">volcanoes</span> in the central and western portions of the arc (177?? E to 175?? W) are <span class="hlt">located</span> atop the northern edge of the ??? 4000-m-high Aleutian ridge. The position of the Quaternary stratocones relative to the edge of the Aleutian ridge appears to strongly control their likelihood for, and direction of, past collapse. The ridge's steep drop to the north greatly increases potential runout length for slides that originate at the island chain. ?? 2007 Elsevier B.V. All rights reserved.</p> <div class="credits"> <p class="dwt_author">Coombs, M. L.; White, S. M.; Scholl, D. W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">224</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012EGUGA..14.1807O"> <span id="translatedtitle">Seismic evidence of a second <span class="hlt">submarine</span> eruption in the north of El Hierro Island</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">From the July 19, 2011 an increase of seismicity, accompanied by a remarkable process of deformation, was detected on the island of El Hierro. This reactivation process, instrumental and scientifically monitored, culminates in the occurrence of a <span class="hlt">submarine</span> eruption, with the emergence of a strong tremor signal, in the south of the island on October 10, 2011. Both processes (unrest and eruption) have different phases and behaviors clearly evidenced by the deformation and seismicity. This work is the result of an exhaustive analysis of seismic signals from three stations deployed on the island of El Hierro(CTAB and CTIG (IGN) and REST (CSIC)), in order to explain the behavior of the volcanic system responsible for the <span class="hlt">submarine</span> eruption of Las Calmas sea and its evolution, as well as evidence of a second <span class="hlt">submarine</span> eruption in the north of the island (ElGolfo). The spectral content of signals from the seismic stations in the north of the island (CTIG and CTAB) and the area around the eruption (REST) has the dominant peak at different frequencies. The amplitude modulations of the seismic noise evolved differently in CTAB and CTIG than REST being particularly significant changes in amplitude and frequency after the occurrence of events of magnitude greater than 4. The evolution of the <span class="hlt">volcano</span>-tectonic cumulative seismic energy shows the occurrence of two similar eruptive episodes, in which two phases can be distinguished. The first phase of both cycles has a constant rate with seismic events of magnitude less than 3 to reach the energy of 10 ^ 11 Joule. From that moment the magnitude grows rapidly exceeding magnitude 4. In the second phase the seismic events are mainly <span class="hlt">located</span> in the south of the island, before the onset of visual evidences of the eruption (October 11, 2011) and later (November 2011) the seismic events are mainly <span class="hlt">located</span> in the north of the island, where no visible signs have been detected. In both cases the appearance or changes in the tremor signal was observed. The presence of a second eruptive vent in the North solves some of the most important enigmas raised from the occurrence of a seismic event of magnitude 4.6 (November 11, 2011). The sudden disappearance of the seismicity in the north of the island is due to the opening of the new eruptive vent and is similar to what happened with the seismicity in the south after the eruption in Las Calmas sea. The pattern of seismic energy release is also similar in the two cases. The strong amplitude modulations in the tremor can be explained as an oscillation in a fluid reservoir with two leaks. This same process explains the rapid oscillations detected in the deformation</p> <div class="credits"> <p class="dwt_author">Ortiz, R.; Berrocoso, M.; de la Cruz-Reyna, S.; Marrero, J. M.; Garcia, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">225</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=ramsdell%2c&id=EJ701041"> <span id="translatedtitle"><span class="hlt">Location</span>, <span class="hlt">Location</span>, <span class="hlt">Location</span>!</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">Of prime importance in real estate, <span class="hlt">location</span> is also a key element in the appeal of romances. Popular geographic settings and historical periods sell, unpopular ones do not--not always with a logical explanation, as the author discovered when she conducted a survey on this topic last year. (Why, for example, are the French Revolution and the…</p> <div class="credits"> <p class="dwt_author">Ramsdell, Kristin</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">226</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012GML....32..473L"> <span id="translatedtitle">New discoveries of mud <span class="hlt">volcanoes</span> on the Moroccan Atlantic continental margin (Gulf of Cádiz): morpho-structural characterization</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">During the MVSEIS-08 cruise of 2008, ten new mud <span class="hlt">volcanoes</span> (MVs) were discovered on the offshore Moroccan continental margin (Gulf of Cádiz) at water depths between 750 and 1,600 m, using multibeam bathymetry, backscatter imagery, high-resolution seismic and gravity core data. Mud breccias were recovered in all cases, attesting to the nature of extrusion of these cones. The mud <span class="hlt">volcanoes</span> are <span class="hlt">located</span> in two fields: the MVSEIS, Moundforce, Pixie, Las Negras, Madrid, Guadix, Almanzor and El Cid MVs in the western Moroccan field, where mud <span class="hlt">volcanoes</span> have long been suspected but to date not identified, and the Boabdil and Al Gacel MVs in the middle Moroccan field. Three main morphologies were observed: asymmetric, sub-circular and flat-topped cone-shaped types, this being the first report of asymmetric morphologies in the Gulf of Cádiz. Based on morpho-structural analysis, the features are interpreted to result from (1) repeated constructive (expulsion of fluid mud mixtures) and destructive (gravity-induced collapse and <span class="hlt">submarine</span> landsliding) episodes and (2) interaction with bottom currents.</p> <div class="credits"> <p class="dwt_author">León, Ricardo; Somoza, Luis; Medialdea, Teresa; Vázquez, Juan Tomás; González, Francisco Javier; López-González, Nieves; Casas, David; del Pilar Mata, María; del Fernández-Puga, María Carmen; Giménez-Moreno, Carmen Julia; Díaz-del-Río, Víctor</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">227</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19820063974&hterms=infrared+detection&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dinfrared%2Bdetection"> <span id="translatedtitle"><span class="hlt">Submarine</span> fresh water outflow detection with a dual-frequency microwave and an infrared radiometer system</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Since infrared measurements are only very slightly affected by whitecap and banking angle influences, the combined multifrequency radiometric signatures of the L-band, the S-band, and an infrared radiometer are used in identifying freshwater outflows (submerged and superficial). To separate the river and lagoon outflows from the <span class="hlt">submarine</span> outflows, geographical maps with a scale of 1:100,000 are used. In all, 44 <span class="hlt">submarine</span> freshwater springs are identified. This is seen as indicating that the <span class="hlt">submarine</span> freshwater outflow <span class="hlt">locations</span> are more numerous around the island than had earlier been estimated. Most of the <span class="hlt">submarine</span> springs are <span class="hlt">located</span> at the northwest and southeast portion of the Puerto Rican coastline; the success in detecting the <span class="hlt">submarine</span> springs during both missions at the northwest portion of the island is 39%. Salinity and temperature distribution plots along the flight path in longitude and latitude coordinates reveal that runoff direction can be determined.</p> <div class="credits"> <p class="dwt_author">Blume, H.-J. C.; Kendall, B. M.; Fedors, J. C.</p> <p class="dwt_publisher"></p> <p class="publishDate">1981-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">228</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=PIA03462&hterms=Leader+manager&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DLeader%2Bmanager"> <span id="translatedtitle">Nyiragonga <span class="hlt">Volcano</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">This image of the Nyiragonga <span class="hlt">volcano</span> eruption in the Congo was acquired on January 28, 2002 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters about 50 to 300 feet ), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.<p/>Image: A river of molten rock poured from the Nyiragongo <span class="hlt">volcano</span> in the Congo on January 18, 2002, a day after it erupted, killing dozens, swallowing buildings and forcing hundreds of thousands to flee the town of Goma. The flow continued into Lake Kivu. The lave flows are depicted in red on the image indicating they are still hot. Two of them flowed south form the <span class="hlt">volcano</span>'s summit and went through the town of Goma. Another flow can be seen at the top of the image, flowing towards the northwest. One of Africa's most notable <span class="hlt">volcanoes</span>, Nyiragongo contained an active lava lake in its deep summit crater that drained catastrophically through its outer flanks in 1977. Extremely fluid, fast-moving lava flows draining from the summit lava lake in 1977 killed 50 to 100 people, and several villages were destroyed. The image covers an area of 21 x 24 km and combines a thermal band in red, and two infrared bands in green and blue.<p/>Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.<p/>The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active <span class="hlt">volcanoes</span>; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">229</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.dartmouth.edu/~volcano/index.html"> <span id="translatedtitle">The Electronic <span class="hlt">Volcano</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">The Electronic <span class="hlt">Volcano</span> offers links to many types of information on active <span class="hlt">volcanoes</span>, such as maps, photographs, full texts of dissertations and a few elusive documents. The Electronic <span class="hlt">Volcano</span> will guide you to resources in libraries or resources on other information servers including catalogs of active <span class="hlt">volcanoes</span>, datasets for literature citations, electronic and hard-copy journals, visual information, maps, observatories and institutions, and a <span class="hlt">volcano</span> name and country index.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">230</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/pp17504"> <span id="translatedtitle">Absolute and relative <span class="hlt">locations</span> of earthquakes at Mount St. Helens, Washington, using continuous data: implications for magmatic processes: Chapter 4 in A <span class="hlt">volcano</span> rekindled: the renewed eruption of Mount St. Helens, 2004-2006</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">This study uses a combination of absolute and relative <span class="hlt">locations</span> from earthquake multiplets to investigate the seismicity associated with the eruptive sequence at Mount St. Helens between September 23, 2004, and November 20, 2004. Multiplets, a prominent feature of seismicity during this time period, occurred as <span class="hlt">volcano</span>-tectonic, hybrid, and low-frequency earthquakes spanning a large range of magnitudes and lifespans. Absolute <span class="hlt">locations</span> were improved through the use of a new one-dimensional velocity model with excellent shallow constraints on P-wave velocities. We used jackknife tests to minimize possible biases in absolute and relative <span class="hlt">locations</span> resulting from station outages and changing station configurations. In this paper, we show that earthquake hypocenters shallowed before the October 1 explosion along a north-dipping structure under the 1980-86 dome. Relative relocations of multiplets during the initial seismic unrest and ensuing eruption showed rather small source volumes before the October 1 explosion and larger tabular source volumes after October 5. All multiplets possess absolute <span class="hlt">locations</span> very close to each other. However, the highly dissimilar waveforms displayed by each of the multiplets analyzed suggest that different sources and mechanisms were present within a very small source volume. We suggest that multiplets were related to pressurization of the conduit system that produced a stationary source that was highly stable over long time periods. On the basis of their response to explosions occurring in October 2004, earthquakes not associated with multiplets also appeared to be pressure dependent. The pressure source for these earthquakes appeared, however, to be different from the pressure source of the multiplets.</p> <div class="credits"> <p class="dwt_author">Thelen, Weston A.; Crosson, Robert S.; Creager, Kenneth C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">231</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFM.V33H..06C"> <span id="translatedtitle">Silicic <span class="hlt">Submarine</span> Eruptions: what can erupted pyroclasts tell us?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Our understanding of <span class="hlt">submarine</span> volcanism is in its infancy with respect to subaerial eruption processes. Two fundamental differences between eruptions in seawater compared to those on land are that (1) eruptions occur at higher confining pressures, and (2) in a seawater medium, which has a higher heat capacity, density and viscosity than air. Together with JAMSTEC collaborators we have a sample suite of <span class="hlt">submarine</span> pumice deposits from modern <span class="hlt">volcanoes</span> of known eruption depths. This sample suite spans a spectrum of eruption intensities, from 1) powerful explosive caldera-forming (Myojin Knoll caldera); to 2) weakly explosive cone building (pre-caldera Myojin Knoll pumice and Kurose-Nishi pumice); to 3) volatile-driven effusive dome spalling (Sumisu knoll A); to 4) passive dome effusion (Sumisu knoll B and C). This sample suite has exceptional potential, not simply because the samples have been taken from well-constrained, sources but because they have similar high silica contents, are unaltered and their phenocrysts contain melt inclusions. Microtextural quantitative analysis has revealed that (i) clast vesicularities remain high (69-90 vol.%) regardless of confining pressure, mass eruption rate or eruption style , (ii) vesicle number densities scale with inferred eruption rate, and (iii) darcian and inertial permeabilities of <span class="hlt">submarine</span> effusive and explosive pyroclasts overlap with explosively-erupted subaerial pyroclasts.</p> <div class="credits"> <p class="dwt_author">Carey, R.; Allen, S.; McPhie, J.; Fiske, R. S.; Tani, K.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">232</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2000GMS...116..223R"> <span id="translatedtitle">Slopes of oceanic basalt <span class="hlt">volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Digital elevation and slope data have been compiled for 15 basaltic <span class="hlt">volcanoes</span> in four oceanic hotspot regions that represent a wide morphological spectrum of young basaltic shields. The data for each region were collected by a different remote-sensing technique: interpolation between spot elevations in orthophoto-quads (Hawaii); TOPSAR single-pass interferometric radar (western Galapagos); ERS1/2 tandem 1-day repeat-pass radar interferometry (Grand Comoro); and SIR-C 1-day repeat-pass radar interferometry (Réunion). These remotely sensed data provide information about the time-integrated typical activity of each <span class="hlt">volcano</span> and allow us to assess the spatial and temporal contributions of various constructional and destructional processes to each <span class="hlt">volcano</span>'s present morphology. Gradual slopes (<5°) occur where lava and tephra pond within calderas or in the saddles between adjacent <span class="hlt">volcanoes</span>, as well as where lava deltas coalesce to form coastal plains. Vent concentration zones (axes of rift zones or Galapagos summit platforms) have slopes ranging from 10 to 12°. Differential vertical growth rates between vent concentration zones and adjacent mostly-lava flanks produce steep constructional slopes up to 40°. The steepest slopes (locally approaching 90°) are produced by fluvial erosion, caldera collapse, faulting, and catastrophic avalanches, all of which are usually identifiable. The quantitative study of <span class="hlt">volcano</span> morphology allows inferences to be made about the nature, <span class="hlt">location</span>, and magnitude of activity over timescales of 100 to 104 years, and the relative importance of particular processes in particular settings holds useful information about internal volcanic structure and evolution. The complex spatial and temporal interplay of these slope-forming processes precludes derivation of <span class="hlt">volcano</span> morphology by numerical modeling of single processes or unidirectional evolutionary schemes. We conclude that the different types of digital elevation data are equally useful for the analysis of volcanic landforms at a scale of a few square kilometers. This is advantageous because future similar work on other <span class="hlt">volcanoes</span> can proceed as new topographic data become available from other sensors.</p> <div class="credits"> <p class="dwt_author">Rowland, Scott K.; Garbeil, Harold</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">233</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://cse.ssl.berkeley.edu/lessons/indiv/coe/summary.html"> <span id="translatedtitle">Surfing for Earthquakes and <span class="hlt">Volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This resource is part of the Science Education Gateway (SEGway) project, funded by NASA, which is a national consortium of scientists, museums, and educators working together to bring the latest science to students, teachers, and the general public. In this lesson, students use the Internet to research data on earthquakes and <span class="hlt">volcanoes</span> and plot <span class="hlt">locations</span> to determine plate boundaries. Extensions include interpretation of interaction between plate boundaries, causes of earthquakes and <span class="hlt">volcanoes</span>, and the comparison of the formation of Olympus Mons on Mars and the Hawaiian volcanic chain. There are worksheets, references, assessment ideas, and vocabulary available for educators.</p> <div class="credits"> <p class="dwt_author">Coe, Patty; Merrick, Michael</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">234</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007AGUFM.B43E1658K"> <span id="translatedtitle">Methane seeps and mud <span class="hlt">volcanoes</span> in the Western Black Sea: First results of RV Meteor cruise M72-4</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Cold seeps are a widespread phenomenon in the Black Sea ranging from seeps in water depths <span class="hlt">located</span> above the gas hydrate stability zone to mud <span class="hlt">volcanoes</span> and seeps associated with gas hydrates in deeper water. In May 2007, RV Meteor cruise M72-4 investigated the distribution of cold seeps as well as the pathways of the fluids in the subsurface by a combination of seismic and geo-acoustic methods (sidescan sonar, Chirp subbottom profiling, reflection seismic and refraction experiments). Two areas have been targeted in particular: the Sorokin Trough southeast of the Crimean peninsula and the continental slope of the Dnepr <span class="hlt">submarine</span> fan further to the West. The Dnepr slope area is characterized by numerous gas emissions situated in water depths of less than 725 metres, while beyond this depth they are almost absent. Raw sidescan images show many individual flares that do not leave a mark on seafloor backscatter intensity, while others coincide with irregular patches of high backscatter intensity. These latter <span class="hlt">locations</span> are associated with higher gas fluxes, but whether high backscatter is related solely to high gas content is yet unclear. The Sorokin Trough, on the other hand, shows the presence of several mud <span class="hlt">volcanoes</span> that show a wide range of morphologies ranging from flat mud pies to large cones with or without calderas. Some of the mud <span class="hlt">volcanoes</span> are aligned, which points to a strong underlying structural control. The source level for all mud <span class="hlt">volcanoes</span> in the Black Sea is <span class="hlt">located</span> in the Late Miocene Maikop formation, which is <span class="hlt">located</span> at a depth of several kilometres in the Sorokin Trough. The dynamics of fluid reservoirs at depth in order to produce mud flow activity with very different rheology at lateral distances of a few kilometres is still under investigation. Several of these mud <span class="hlt">volcanoes</span> show recent activity through either mud flows or gas flares. The gas flares are surprising as the mud <span class="hlt">volcanoes</span> lie in water depths of around 2000 metres, i.e. well within the depth of gas hydrate stability. However, this flare activity is intermittent. geomar.de/index.php?id=seepmod</p> <div class="credits"> <p class="dwt_author">Klaucke, I.; Bialas, J.; Petersen, C. J.; Netzeband, G. L.; Wagner, G.; Fink, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">235</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE89770194"> <span id="translatedtitle">Exhaust Gas Turbocharged <span class="hlt">Submarine</span> Engines.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">Supercharged <span class="hlt">submarine</span> propulsion systems have the following technical and economic advantages: Higher power density, lower fuel consumption, maximum identity with standard propulsion systems. The design and successful tests of a new supercharger (simple ...</p> <div class="credits"> <p class="dwt_author">V. M. W. Jost</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">236</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=ADA386504"> <span id="translatedtitle">Next Generation Strategic <span class="hlt">Submarine</span> Navigator.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">For the last forty-five years, Strategic Systems Programs (SSP) has been entrusted with total life cycle responsibility for the United States and the Royal (United Kingdom) Navy's Strategic <span class="hlt">Submarine</span> (SSBN) launched ballistic missile weapons systems. SSP'...</p> <div class="credits"> <p class="dwt_author">M. J. Ringlein N. J. Barnett M. B. May</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">237</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/55743813"> <span id="translatedtitle">Geochemistry Of Historical Lavas From Guagua Pichincha <span class="hlt">Volcano</span> (Ecuador) : Inferences On Deep Structure Of Adakitic <span class="hlt">Volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Guagua Pichincha is an active Ecuadorian stratovolcano <span class="hlt">located</span> near the capital city Quito. Violent phreatic and preatomagmatic eruptions since 1999 have sparked a new interest in studying this <span class="hlt">volcano</span>. Here are presented results of an ongoing geochemical study of historical and actual products. Major and trace elements have shown that this <span class="hlt">volcano</span> is adakitic (high MgO dacites showing, for example,</p> <div class="credits"> <p class="dwt_author">J. Chmeleff; O. Sigmarsson</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">238</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/52168666"> <span id="translatedtitle">Distribution of Water in Earth's Mantle - Implications from Samoan <span class="hlt">Submarine</span> Lavas</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We report volatile and trace element data for <span class="hlt">submarine</span>, basaltic glasses from the three youngest Samoan <span class="hlt">volcanoes</span>, Ta'u, Malumalu and Vailulu'u - some of which define (by Sr-Nd-Pb isotope compositions) the enriched mantle endmember, EM2 (Zindler and Hart, 1986). Shallow degassing has affected CO2 in all samples, and H2O only in the most shallowly erupted samples from Vailulu'u. Absolute water</p> <div class="credits"> <p class="dwt_author">R. K. Workman; E. Hauri; S. R. Hart; J. Wang; J. Blusztajn</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">239</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.bbc.co.uk/radio4/science/frontiers_20021009.shtml"> <span id="translatedtitle">Super <span class="hlt">Volcano</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">Deep beneath the surface of Earth lies one of the most destructive and yet least understood of the natural forces on the planet: the super <span class="hlt">volcano</span>. This radio broadcast presents discussions with scientists at Yellowstone National Park who are investigating this potentially devastating natural phenomenon. Yellowstone National Park is one of the largest supervolcanoes in the world. It last erupted 640,000 years ago and scientists are now predicting that the next eruption may not be far off. To discover more, a new volcanic observatory has been built in the park to monitor the extreme volcanic activity going on beneath the surface of this much visited destination. The broadcast is 30 minutes in length.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">240</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/51342242"> <span id="translatedtitle">Obstacle avoidance sonar for <span class="hlt">submarines</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The Advanced Mine Detection Sonar (AMDS) system was designed to operate in poor environments with high biological and\\/or shallow-water boundary conditions. It provides increased capability for active detection of volume, close-tethered, and bottom mines, as well as <span class="hlt">submarine</span> and surface target active\\/passive detection for ASW and collision avoidance. It also provides bottom topography mapping capability for precise <span class="hlt">submarine</span> navigation in</p> <div class="credits"> <p class="dwt_author">Albert C. Dugas; Kenneth M. Webman</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_11");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">241</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/52769972"> <span id="translatedtitle">A Magma Genesis Model to Explain Growth History of Hawaiian <span class="hlt">Volcanoes</span>: Perspectives of 2001-2002 JAMSTEC Hawaii Cruises</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The 2001 and 2002 JAMSTEC Hawaii cruises have been carried out using RV-Kairei with ROV-Kaiko and RV-Yokosuka with submersible Shinaki-6500, respectively. The main focus of these cruises is 1) to clarify the growth history of Hawaiian <span class="hlt">volcanoes</span> through geological study on deep <span class="hlt">submarine</span> exposures, 2) to understand the nature of <span class="hlt">submarine</span> rifts, 3) to understand the nature of magmas erupted</p> <div class="credits"> <p class="dwt_author">E. Takahashi</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">242</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=ADA382255"> <span id="translatedtitle">Relationship Between a <span class="hlt">Submarine</span>'s Maximum Speed And its Evasive Capability.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">The experiences of <span class="hlt">submarine</span> warfare from WWI and WWII have generally dictated maximum speed when designing conventional <span class="hlt">submarines</span>. Technological development of <span class="hlt">submarine</span> and antisubmarine weapons, however, requires examination of <span class="hlt">submarine</span> warfare and t...</p> <div class="credits"> <p class="dwt_author">K. R. Armo</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">243</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19810054384&hterms=submarines&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dsubmarines"> <span id="translatedtitle">Multifrequency radiometer detection of <span class="hlt">submarine</span> freshwater sources along the Puerto Rican coastline</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The surface area above <span class="hlt">submarine</span> springs of fresh water exhibit temperatures and salinities lower than the surrounding sea waters. A multifrequency radiometer system which earlier demonstrated an accuracy of 1 degree C and 1 part per thousand in remotely detecting the surface temperature and salinities, respectively, was used to detect <span class="hlt">submarine</span> freshwater springs. The first mission on February 4, 1978, consisted of overflight measurements over three fourths of the coastal areas around the Island of Puerto Rico. During the second mission on February 6, 1978, special attention was directed to the northwest portion of Puerto Rico where several <span class="hlt">submarine</span> springs had been reported. The previously reported spring <span class="hlt">locations</span> correlated well with the <span class="hlt">locations</span> detected by the radiometers. After separating the surface runoffs such as rivers, lagoons, marshes, and bays, 44 <span class="hlt">submarine</span> freshwater springs were identified which indicates that the <span class="hlt">submarine</span> freshwater outflow <span class="hlt">locations</span> are more numerous around the island than had earlier been estimated. The majority of the <span class="hlt">submarine</span> springs are <span class="hlt">located</span> at the northwest and southeast portion of the Puerto Rican coastline. The success of detecting the same <span class="hlt">submarine</span> springs during both missions at the northwest portion of the island was 39%.</p> <div class="credits"> <p class="dwt_author">Blume, H.-J. C.; Kendall, B. M.; Fedors, J. C.</p> <p class="dwt_publisher"></p> <p class="publishDate">1981-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">244</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19800039554&hterms=history+volcanoes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dhistory%2Bvolcanoes"> <span id="translatedtitle">The chronology of the martian <span class="hlt">volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The <span class="hlt">volcanoes</span> of Mars have been divided into three groups based on morphology: basaltic shields, domes and composite cones, and highland patera. A fourth group can be added to include the <span class="hlt">volcano</span>-tectonic depressions. Using crater counts and the absolute chronology of Soderblom, an attempt is made to estimate the history of the <span class="hlt">volcanoes</span>. Early in the martian history, about 2.5 b.y. ago, all three styles of <span class="hlt">volcanoes</span> were active at various <span class="hlt">locations</span> on the surface. At approximately 1.7-1.8 b.y. ago a transition occurred in the style and loci of volcanic construction. <span class="hlt">Volcanoes</span> of younger age appear to be only of the basaltic shield group and are restricted to the Tharsis region. This same transition was noted by a change in the style of the basaltic shield group. Older shields were small low features, while the younger shields are significantly broader and taller.</p> <div class="credits"> <p class="dwt_author">Plescia, J. B.; Saunders, R. S.</p> <p class="dwt_publisher"></p> <p class="publishDate">1979-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">245</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/41005430"> <span id="translatedtitle">On the frontal dynamics and morphology of <span class="hlt">submarine</span> debris flows</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Several <span class="hlt">submarine</span> debris flows show an apparently chaotic frontal part with blocks of variable size (from roughly tens to some hundreds of metres) <span class="hlt">located</span> some distance beyond the front of the main deposits. This outrunner phenomenon was studied both in the field and in laboratory experiments. Depositional patterns in a field case (Finneidfjord, northern Norway) are classified from the outer</p> <div class="credits"> <p class="dwt_author">Trygve Ilstad; Fabio V. De Blasio; Anders Elverhøi; Carl B. Harbitz; Lars Engvik; Oddvar Longva; Jeffrey G. Marr</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">246</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1982STIN...8322827C"> <span id="translatedtitle">Fuel-cell-propelled <span class="hlt">submarine</span>-tanker-system study</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A systems analysis of a commercial Arctic Ocean <span class="hlt">submarine</span> tanker system to carry fossil energy to markets is presented. The <span class="hlt">submarine</span> is to be propelled by a modular phosphoric acid fuel cell system. An electric utility type fuel cell will be fueled with methanol. Oxidant will be provided from a liquid oxygen tank carried onboard. The route will be under the polar icecap from a loading terminal <span class="hlt">located</span> off Prudhoe Bay, Alaska to a transshipment facility postulated to be in a Norwegian fjord. The system throughput of the gas fed methanol cargo will be 450,000 barrels per day.</p> <div class="credits"> <p class="dwt_author">Court, K. E.; Kumm, W. H.; Ocallaghan, J. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">247</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007AGUFM.V33A1174X"> <span id="translatedtitle">Penguin Bank: A Loa-Trend Hawaiian <span class="hlt">Volcano</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Hawaiian <span class="hlt">volcanoes</span> along the Hawaiian Ridge from Molokai Island in the northwest to the Big Island in the southeast, define two parallel trends of <span class="hlt">volcanoes</span> known as the Loa and Kea spatial trends. In general, lavas erupted along these two trends have distinctive geochemical characteristics that have been used to define the spatial distribution of geochemical heterogeneities in the Hawaiian plume (e.g., Abouchami et al., 2005). These geochemical differences are well established for the <span class="hlt">volcanoes</span> forming the Big Island. The longevity of the Loa- Kea geochemical differences can be assessed by studying East and West Molokai <span class="hlt">volcanoes</span> and Penguin Bank which form a volcanic ridge perpendicular to the Loa and Kea spatial trends. Previously we showed that East Molokai <span class="hlt">volcano</span> (~1.5 Ma) is exclusively Kea-like and that West Molokai <span class="hlt">volcano</span> (~1.8 Ma) includes lavas that are both Loa- and Kea-like (Xu et al., 2005 and 2007).The <span class="hlt">submarine</span> Penguin Bank (~2.2 Ma), probably an independent <span class="hlt">volcano</span> constructed west of West Molokai <span class="hlt">volcano</span>, should be dominantly Loa-like if the systematic Loa and Kea geochemical differences were present at ~2.2 Ma. We have studied 20 samples from Penguin Bank including both <span class="hlt">submarine</span> and subaerially-erupted lavas recovered by dive and dredging. All lavas are tholeiitic basalt representing shield-stage lavas. Trace element ratios, such as Sr/Nb and Zr/Nb, and isotopic ratios of Sr and Nd clearly are Loa-like. On an ?Nd-?Hf plot, Penguin Bank lavas fall within the field defined by Mauna Loa lavas. Pb isotopic data lie near the Loa-Kea boundary line defined by Abouchami et al. (2005). In conclusion, we find that from NE to SW, i.e., perpendicular to the Loa and Kea spatial trend, there is a shift from Kea-like East Molokai lavas to Loa-like Penguin Bank lavas with the intermediate West Molokai <span class="hlt">volcano</span> having lavas with both Loa- and Kea-like geochemical features. Therefore, the Loa and Kea geochemical dichotomy exhibited by Big Island <span class="hlt">volcanoes</span> existed at ~2.2 Ma when the Molokai Island <span class="hlt">volcanoes</span> formed and has persisted until the present. References: Abouchami et al., 2005 Nature, 434:851-856 Xu et al., 2005 G3, doi: 10.1029/2004GC000830 Xu et al., 2007 G3, doi: 10.1029/2006GC001554</p> <div class="credits"> <p class="dwt_author">Xu, G.; Blichert-Toft, J.; Clague, D. A.; Cousens, B.; Frey, F. A.; Moore, J. G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">248</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008JSV...311..224P"> <span id="translatedtitle">Active control of radiated pressure of a <span class="hlt">submarine</span> hull</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A theoretical analysis of the active control of low-frequency radiated pressure from <span class="hlt">submarine</span> hulls is presented. Two typical hull models are examined in this paper. Each model consists of a water-loaded cylindrical shell with a hemispherical shell at one end and conical shell at the other end, which forms a simple model of a <span class="hlt">submarine</span> hull. The conical end is excited by an axial force to simulate propeller excitations while the other end is free. The control action is implemented through a Tee-sectioned circumferential stiffener driven by pairs of PZT stack actuators. These actuators are <span class="hlt">located</span> under the flange of the stiffener and driven out of phase to produce a control moment. A number of cost functions for minimizing the radiated pressure are examined. In general, it was found that the control system was capable of reducing more than half of the total radiated pressure from each of the <span class="hlt">submarine</span> hull for the first three axial modes.</p> <div class="credits"> <p class="dwt_author">Pan, Xia; Tso, Yan; Juniper, Ross</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">249</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://volcano.oregonstate.edu/vwdocs/vwlessons/volcano_types/index.html"> <span id="translatedtitle">Types of <span class="hlt">Volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This <span class="hlt">volcano</span> resource introduces the six-type classification system and points out weaknesses of the classic three-type system. The six types of <span class="hlt">volcanoes</span> are shield <span class="hlt">volcanoes</span>, strato <span class="hlt">volcanoes</span>, rhyolite caldera complexes, monogenetic fields, flood basalts, and mid-ocean ridges. For each type of <span class="hlt">volcano</span> there is a description of both structure and dynamics along with examples of each. You can account for more than ninty percent of all <span class="hlt">volcanoes</span> with these six types. Additionally, any system will be more useful if you use modifiers from the other potential classification schemes with the morphological types.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">250</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009Tectp.465..136D"> <span id="translatedtitle">Seismicity and active tectonics at Coloumbo Reef (Aegean Sea, Greece): Monitoring an active <span class="hlt">volcano</span> at Santorini Volcanic Center using a temporary seismic network</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The volcanic center of Santorini Island is the most active <span class="hlt">volcano</span> of the southern Aegean volcanic arc. ? dense seismic array consisting of fourteen portable broadband seismological stations has been deployed in order to monitor and study the seismo-volcanic activity at the broader area of the Santorini volcanic center between March 2003 and September 2003. Additional recordings from a neighbouring larger scale temporary network (CYCNET) were also used for the relocation of more than 240 earthquakes recorded by both arrays. A double-difference relocation technique was used, in order to obtain optimal focal parameters for the best-constrained earthquakes. The results indicate that the seismic activity of the Santorini volcanic center is strongly associated with the tectonic regime of the broader Southern Aegean Sea area as well as with the volcanic processes. The main cluster of the epicenters is <span class="hlt">located</span> at the Coloumbo Reef, a <span class="hlt">submarine</span> <span class="hlt">volcano</span> of the volcanic system of Santorini Islands. A smaller cluster of events is <span class="hlt">located</span> near the Anydros Islet, aligned in a NE-SW direction, running almost along the main tectonic feature of the area under study, the Santorini-Amorgos Fault Zone. In contrast, the main Santorini Island caldera is characterized by the almost complete absence of seismicity. This contrast is in very good agreement with recent volcanological and marine studies, with the Coloumbo volcanic center showing an intense high-temperature hydrothermal activity, in comparison to the corresponding low-level activity of the Santorini caldera. The high-resolution hypocentral relocations present a clear view of the volcanic <span class="hlt">submarine</span> structure at the Coloumbo Reef, showing that the main seismic activity is <span class="hlt">located</span> within a very narrow vertical column, mainly at depths between 6 and 9 km. The focal mechanisms of the best-<span class="hlt">located</span> events show that the cluster at the Coloumbo Reef is associated with the "Kameni-Coloumbo Fracture Zone", which corresponds to the western termination of the major ENE-WSW Santorini-Amorgos Fault Zone. Stress-tensor inversion of the available fault plane solutions from Coloumbo Reef, as well as existing neotectonic fault information from NE Santorini (Coloumbo peninsula), suggests that the NE Santorini-Coloumbo faults belong to a single rupture system, with a ~ 30° rotation of the local stress field with respect to the NNW-SSE regional extension field of the southern Aegean Sea. The observed change of the fault plane solutions shows that local conditions at the Coloumbo <span class="hlt">submarine</span> <span class="hlt">volcano</span> area control the observed faulting pattern.</p> <div class="credits"> <p class="dwt_author">Dimitriadis, I.; Karagianni, E.; Panagiotopoulos, D.; Papazachos, C.; Hatzidimitriou, P.; Bohnhoff, M.; Rische, M.; Meier, T.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">251</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1982EOSTr..63Q.817B"> <span id="translatedtitle"><span class="hlt">Submarine</span> hydrothermal fossils confirmed</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Researchers from Princeton University (D. Crerrar et al, Econ. Geol., May 1982) have documented, in considerable detail, evidence for the formation of some of the 800 or more manganiferous chert deposits occurring in the central belt of the Fransiscan formation in northwestern California. They confirm the surprisingly old conclusion o f Tiaferro and Hudson (Cal. Div. Mines Bull., 125, 217-276, 1943) that the Fransiscan chert deposits probably represent the fossil remains of <span class="hlt">submarine</span> hydrothermal vents.The deposits resemble recently discovered hydrothermal mounds near the Galapagos rift, the Gulf of Aden, and the Mid-Atlantic Ridge. As the Princeton investigators point out, there are important implications of the existence of deep hydrothermal circulation systems at oceanic spreading centers throughout geologic time. They note that the calculated annual flow of hydrothermal fluids in such processes is about 1017 g, which implies that the entire volume of the oceans could circulate completely every 10 million years. With such circulation, the hydrothermal processes along midocean ridges could control the composition of seawater and strongly influence the geochemical flux of elements in the marine environment.</p> <div class="credits"> <p class="dwt_author">Bell, Peter M.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">252</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=ADA313584"> <span id="translatedtitle">Nutrition Education And Diet Modification Aboard <span class="hlt">Submarines</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">During a one year period, 534 male, US Navy <span class="hlt">submariners</span> participated in a nutrition research project designed to reduce coronary heart disease (CHD) risk. The research was carried out on board USN Trident <span class="hlt">Submarines</span> before, during, and following actual pa...</p> <div class="credits"> <p class="dwt_author">C. L. Shake C. L. Schlichting</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">253</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=ADA304112"> <span id="translatedtitle">Fuel Cell Air Independent Propulsion of <span class="hlt">Submarines</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">Conventional diesel-electric <span class="hlt">submarines</span> must surface periodically to recharge their batteries by using generators driven by air breathing diesel engines. During this time, <span class="hlt">submarines</span> are most vulnerable to detection. Air independent propulsion (AIP) syste...</p> <div class="credits"> <p class="dwt_author">P. L. Mart J. Margeridis</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">254</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=ADA196243"> <span id="translatedtitle">Analysis of <span class="hlt">Submarine</span> Tender Manning Issues.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">The increased workload at <span class="hlt">submarine</span> Intermediate Maintenance Activities (IMAs) and problems in adequately manning these facilities could affect <span class="hlt">submarine</span> maintenance. This research memorandum contains a brief analysis of the personnel and requirements iss...</p> <div class="credits"> <p class="dwt_author">A. J. Marcus M. F. Hayes</p> <p class="dwt_publisher"></p> <p class="publishDate">1988-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">255</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/mf2255"> <span id="translatedtitle">Bathymetry of the southwest flank of Mauna Loa <span class="hlt">Volcano</span>, Hawaii</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Much of the seafloor topography in the map area is on the southwest <span class="hlt">submarine</span> flank of the currently active Mauna Loa <span class="hlt">Volcano</span>. The benches and blocky hills shown on the map were shaped by giant landslides that resulted from instability of the rapidly growing <span class="hlt">volcano</span>. These landslides were imagined during a 1986 to 1991 swath sonar program of the United States Hawaiian Exclusive Economic Zone, a cooperative venture by the U.S. Geological Survey and the British Institute of Oceanographic Sciences (Lipman and others, 1988; Moore and others, 1989). Dana Seamount (and probably also the neighboring Day Seamount) are apparently Cretaceous in age, based on paleomagnetic studies, and predate the growth of the Hawaiian Ridge <span class="hlt">volcanoes</span> (Sager and Pringle, 1990).</p> <div class="credits"> <p class="dwt_author">Chadwick, William W.; Moore, James G.; Fox, Christopher G.</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">256</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.geo.mtu.edu/volcanoes/"> <span id="translatedtitle">MTU <span class="hlt">Volcanoes</span> Page</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">Michigan Technological University <span class="hlt">Volcanoes</span> Page, which is sponsored by the Keweenaw <span class="hlt">Volcano</span> Observatory, aims to provide information about <span class="hlt">volcanoes</span> to the public and to complement other informational sites on the Web. Visitors will find information on what a <span class="hlt">volcano</span> is, currently active <span class="hlt">volcanoes</span> throughout the world, remote sensing of <span class="hlt">volcanoes</span>, volcanic humor, and much more. The <span class="hlt">volcano</span> hazard section of the site contains primarily original content that provides a Basic Guide to Volcanic Hazards and details Volcanic Cloud Hazards to Aviation, while offering <span class="hlt">volcano</span> safety recommendations to the public. Although the site could use an update to its layout and organization, it does do a good job of presenting an interesting mix of unique information.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">257</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://geographyworldonline.com/volcano.html"> <span id="translatedtitle">Geography World - <span class="hlt">Volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This portal provides links to an extensive list of <span class="hlt">volcano</span>-related websites for the United States and around the world. Users can access articles, maps, glossaries, webcams, a dictionary of <span class="hlt">volcanoes</span>, and many other resources.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">258</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://gallery.usgs.gov/photos/03_04_2009_u05Ctg2SRn_03_04_2009_2"> <span id="translatedtitle">Ol Doinyo Lengai <span class="hlt">Volcano</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://gallery.usgs.gov/">USGS Multimedia Gallery</a></p> <p class="result-summary">Scientists from the <span class="hlt">Volcano</span> Disaster Assistance Program team and the Geological Survey of Tanzania take a sample of the most recent ashfall from Ol Doinyo Lengai as the <span class="hlt">volcano</span> looms in the background....</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2009-03-04</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">259</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004AGUFM.G43C..05H"> <span id="translatedtitle"><span class="hlt">Volcano</span>-Tectonic Deformation at Taal <span class="hlt">Volcano</span>, Philippines</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Taal <span class="hlt">Volcano</span>, <span class="hlt">located</span> in southern Luzon, Philippines, is an unusual, tholeiitic <span class="hlt">volcano</span> situated within a calc-alkaline arc. It is one of the most active volcanic centers in the Philippines, with some 33 historic volcanic eruptions over the past four centuries. Volcanism at Taal is at least partly tectonically controlled, suggested by its <span class="hlt">location</span> at the intersection of regional fault structures and by the <span class="hlt">location</span> and shape of both Taal's caldera and <span class="hlt">Volcano</span> Island. The alignment of modern eruption centers, are controlled by regional and local structures. Here, we review geomorphic and geodetic observations that constrain both tectonic and volcanic deformation in the vicinity of Taal <span class="hlt">volcano</span>. We use GPS measurements from a 52-station GPS network measured from 1996 - 2001 to investigate overall plate interaction and microplate (intra-arc) deformation. The velocity field indicates that the majority of the Philippine Sea - Eurasia plate convergence is taking place west of Luzon, presumably largely by subduction at the Manila trench. A relatively small fraction of the convergence appears to be taking place within Luzon or across the East Luzon trough. The major intra-arc deformation is accommodated by strike-slip motion along the Philippine Fault, ranging from 25-40 mm/yr left-lateral slip. Detailed measurements in southern Luzon also indicate significant intra-arc deformation west of the Philippine Fault. GPS measurements in southwestern Luzon indicate significant motion within the arc, which could be explained by 11-13 mm/yr of left-lateral shear along the "Macolod Corridor", within which Taal <span class="hlt">Volcano</span> resides. A dense network of continuous single- and dual-frequency GPS receivers at Taal <span class="hlt">Volcano</span>, Philippines reveals highly time-variable deformation behavior, similar to that observed at other large calderas. While the caldera has been relatively quiescent for the past 2-3 years, previous deformation includes two major phases of intra-caldera deformation, including two phases of inflation and deflation in 1998-2000. The February-November 2000 period of inflation was characterized by approximately 120 mm of uplift of the center of <span class="hlt">Volcano</span> Island relative to the northern caldera rim, at average rates up to 216 mm/yr. The source of deflation in 1999 was modeled as a contractional Mogi point source centered at 4.2 km depth beneath <span class="hlt">Volcano</span> Island; the source of inflation in 2000 was modeled as a dilatational Mogi point source centered at 5.2 km depth beneath <span class="hlt">Volcano</span> Island. The <span class="hlt">locations</span> of the two sources are indistinguishable within the 95% confidence estimates. Modeling using a running four-month time window from June 1999-March 2001 reveals little evidence for source migration. We find marginal evidence for an elongate source whose long axis is oriented NW-SE, paralleling the caldera-controlling fault system. We suggest that the two periods of inflation observed at Taal represent episodic intrusions of magma into a shallow reservoir centered beneath <span class="hlt">Volcano</span> Island whose position is controlled at least in part by regional tectonic structures.</p> <div class="credits"> <p class="dwt_author">Hamburger, M. W.; Galgana, G.; Corpuz, E.; Bartel, B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">260</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007AGUSM.V51A..08D"> <span id="translatedtitle">Revisiting Jorullo <span class="hlt">volcano</span> (Mexico): monogenetic or polygenetic <span class="hlt">volcano</span>?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Jorullo <span class="hlt">volcano</span> is <span class="hlt">located</span> near the volcanic front of the westernmost part of the Trans-Mexican Volcanic Belt, which is related to the subduction of the Cocos plate beneath the North American plate. This part of the TMVB is known as the Michoacán-Guanajuato Volcanic Field, a region where widespread monogenetic volcanism is present although polygenetic volcanism is also recognized (i. e. Tancítaro <span class="hlt">volcano</span>; Ownby et al., 2006). Jorullo <span class="hlt">volcano</span> was born in the middle of crop fields. During its birth several lava flows were emitted and several cones were constructed. The main cone is the Jorullo proper, but there is a smaller cone on the north (Volcán del Norte), and three smaller cones aligned N-S on the south (Unnamed cone, UC; Volcán de Enmedio, VE; and Volcán del Sur, VS). The cone of Jorullo <span class="hlt">volcano</span> is made up of tephra and lava flows erupted from the crater. The three southern cones show very interesting histories not described previously. VE erupted highly vesiculated tephras including xenoliths from the granitic basement. VS is made of spatter and bombs. A very well preserved hummocky morphology reveals that VE and VS collapsed towards the west. After the collapses, phreatomagmatic activity took place at the UC blanketing VE, VS and the southern flank of the Jorullo cone with sticky surge deposits. The excellent study by Luhr and Carmichael (1985) indicates that during the course of the eruption, lavas evolved from primitive basalt to basaltic andesite, although explosive products show a reverse evolution pattern (Johnson et al., 2006). We mapped lava flows not described by the observers in the 18th century nor considered in previous geologic reports as part of the Jorullo lavas. These lavas are older, distributed to the west and south, and some of them resemble the lava flows from La Pilita <span class="hlt">volcano</span>, a cone older than Jorullo (Luhr and Carmichael, 1985). These lava flows were not considered before because they were not extruded during the 1759-1774 eruption. Therefore, in spite of the long-standing idea of Jorullo being a monogenetic <span class="hlt">volcano</span>, we hypothesize it as a stratovolcano in the making. The polygenetic nature of the <span class="hlt">volcano</span> and the processes described here for Jorullo <span class="hlt">volcano</span> (cone collapse, phreatomagmatic activity) are of great importance because of their implications for hazards assessment.</p> <div class="credits"> <p class="dwt_author">Delgado Granados, H.; Roberge, J.; Farraz Montes, I. A.; Victoria Morales, A.; Pérez Bustamante, J. C.; Correa Olan, J. C.; Gutiérrez Jiménez, A. J.; Adán González, N.; Bravo Cardona, E. F.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-05-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_12");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">261</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/54637661"> <span id="translatedtitle">Source Signature of Sr Isotopes in Fluids Emitting From Mud <span class="hlt">volcanoes</span> in Taiwan</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Located</span> at the boundary between the Philippine Sea Plate and the Asia Continental Plate, abundance of mud <span class="hlt">volcanoes</span> were erupted on land in Taiwan. According to their occurrences and associated tectonic settings, these mud <span class="hlt">volcanoes</span> were classified into four groupies. The group (I) mud <span class="hlt">volcanoes</span> are <span class="hlt">located</span> in the western coastal plane, whereas group (II) and (III) are situated near</p> <div class="credits"> <p class="dwt_author">C. Chung; C. You; H. Chao</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">262</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/48942405"> <span id="translatedtitle">Stratigraphy of the Hawai‘i Scientific Drilling Project core (HSDP2): Anatomy of a Hawaiian shield <span class="hlt">volcano</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The Hawai‘i Scientific Drilling Project (HSDP2) successfully drilled ?3.1 km into the island of Hawai‘i. Drilling started on Mauna Loa <span class="hlt">volcano</span>, drilling 247 m of subaerial lavas before encountering 832 m of subaerial Mauna Kea lavas, followed by 2019 m of <span class="hlt">submarine</span> Mauna Kea volcanic and sedimentary units. The 2.85 km stratigraphic record of Mauna Kea <span class="hlt">volcano</span> spans back to</p> <div class="credits"> <p class="dwt_author">Michael O. Garcia; Eric H. Haskins; Edward M. Stolper; Michael Baker</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">263</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2003AGUFM.V42B0365S"> <span id="translatedtitle">Facies analysis of Hlodufell basaltic subglacial to emergent <span class="hlt">volcano</span>, SW Iceland: insights into sub-ice growth mechanisms and meltwater drainage</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Hlodufell is a subglacial to emergent basaltic <span class="hlt">volcano</span> <span class="hlt">located</span> 9km south of the Langjokull ice-cap in SW Iceland. This study is the first detailed facies analysis of this well-known <span class="hlt">volcano</span>. The vertical facies architecture of the basal half of the <span class="hlt">volcano</span> is typical of many basaltic subaqueous (including <span class="hlt">submarine</span>) to emergent <span class="hlt">volcanoes</span>, comprising basal pillow mounds overlain by Surtseyan eruption-fed subaqueously-deposited sediment gravity flows. However, facies in the upper part of the edifice demonstrate the influence of variable water levels more typical of englacial lakes. The Surtseyan sequence is overlain by two subaerial lava flow and cogenetic lava-fed delta sequences, separated by a second Surtseyan sequence. In addition, the uppermost lava flows are also draped by a thin veneer of Surtseyan tephra. Both lava-fed delta sequences are unusually dominated by subaerial lava breccias. This may be due to a number of factors that influence steep slope stability but the possibility of retreating ice walls should be considered. Detailed facies analysis also revealed evidence of the influence of ice on eruptive and depositional products throughout the history of the edifice. Some of the basal pillow mounds preserve metre-sized cavities with partial hyaloclastite fills, interpreted as meltout structures formed during sub-ice growth by ice-block stoping. Some mounds also have steep chill surfaces where pillows have been compressed against a rigid wall (now absent) interpreted as ice. The peripheral pillow mounds, particularly those to the immediate south of Hlodufell (Rani area) are draped by Surtseyan eruption-fed tephra deposited by erosive meltwater streamflows. The draping tephra was derived from both the first and second Surtseyan sequences. These observations illustrate that direct ice-contact and ice-block stoping was important during initial construction of the <span class="hlt">volcano</span> and that meltwater drainage (particularly to the south) was important throughout its history.</p> <div class="credits"> <p class="dwt_author">Skilling, I. P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">264</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/55454764"> <span id="translatedtitle">On sonobuoy placement for <span class="hlt">submarine</span> tracking</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This paper addresses the problem of detecting and tracking an unknown number of <span class="hlt">submarines</span> in a body of water using a known number of moving sonobuoys. Indeed, we suppose there are N <span class="hlt">submarines</span> collectively maneuvering as a weakly interacting stochastic dynamical system, where N is a random number, and we need to detect and track these <span class="hlt">submarines</span> using M moving</p> <div class="credits"> <p class="dwt_author">Michael A. Kouritzin; David J. Ballantyne; Hyukjoon Kim; Yaozhong Hu</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">265</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/50135110"> <span id="translatedtitle">Assembly challenges in <span class="hlt">submarine</span> system optical components</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The hallmark of components for <span class="hlt">submarine</span> applications is reliability. Assembly and manufacture of these components requires scrupulous control of incoming parts and assembly processes, particularly the fiber pigtail. Although there are many aspects to assembly of <span class="hlt">submarine</span> system optical components, this talk will focus on our experience with handling fibers, controlling suppliers, monitoring processes and assuring reliability for <span class="hlt">submarine</span> system</p> <div class="credits"> <p class="dwt_author">R. C. Schweizer; K. A. Miller; G. M. Palmer; K. C. Robinson</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">266</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.geology.sdsu.edu/how_volcanoes_work/index.html"> <span id="translatedtitle">How <span class="hlt">Volcanoes</span> Work</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This educational resource describes the science behind <span class="hlt">volcanoes</span> and volcanic processes. Topics include volcanic environments, <span class="hlt">volcano</span> landforms, eruption dynamics, eruption products, eruption types, historical eruptions, and planetary volcanism. There are two animations, over 250 images, eight interactive tests, and a <span class="hlt">volcano</span> crossword puzzle.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2011-04-18</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">267</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=volcanoes&pg=4&id=EJ273318"> <span id="translatedtitle">A Scientific Excursion: <span class="hlt">Volcanoes</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">Reviews an educationally valuable and reasonably well-designed simulation of volcanic activity in an imaginary land. <span class="hlt">VOLCANOES</span> creates an excellent context for learning information about <span class="hlt">volcanoes</span> and for developing skills and practicing methods needed to study behavior of <span class="hlt">volcanoes</span>. (Author/JN)</p> <div class="credits"> <p class="dwt_author">Olds, Henry, Jr.</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">268</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=PIA04503&hterms=vents&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dvents"> <span id="translatedtitle"><span class="hlt">Volcano</span> Vents</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary"><p/> [figure removed for brevity, see original site] <p/>Released 5 May 2003<p/>This low-relief shield <span class="hlt">volcano</span> imaged with the THEMIS visible camera has two large vents which have erupted several individual lava flows. The positions of the origins of many of the flows indicate that it is probable that the vents are secondary structures that formed only after the shield was built up by eruptions from a central caldera.<p/>Image information: VIS instrument. Latitude 17.6, Longitude 243.6 East (116.4 West). 19 meter/pixel resolution.<p/>Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.<p/>NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.<p/></p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">269</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/53013550"> <span id="translatedtitle">Origins of Newberry <span class="hlt">Volcano</span>, Central Oregon: A Cascade Backarc, High Lava Plains, Basin and Range Shield <span class="hlt">Volcano</span>?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Newberry <span class="hlt">Volcano</span>, <span class="hlt">located</span> 60 km east of the central Oregon High Cascades resides in a complex tectonic and volcanic region. Understanding the petrogenesis of Newberry <span class="hlt">Volcano</span> is important to understanding the regional geological framework because of its <span class="hlt">location</span> at the confluence of the back-arc of the Oregon Cascades, the northern end of the Basin and Range, and the western end</p> <div class="credits"> <p class="dwt_author">M. C. Rowe; A. J. Kent; R. L. Nielsen; P. J. Wallace; J. M. Donnelly-Nolan</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">270</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://vulcan.wr.usgs.gov/"> <span id="translatedtitle">Cascades <span class="hlt">Volcano</span> Observatory</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This is the homepage of the United States Geological Survey's (USGS) Cascades <span class="hlt">Volcano</span> Observatory (CVO). The site features news and events, updates on current activity of Cascade Range <span class="hlt">volcanoes</span>, and information summaries on each of the <span class="hlt">volcanoes</span> in the range. There are also hazard assessment reports, maps, and a 'Living with <span class="hlt">Volcanoes</span>' feature that provides general interest information. A set of menus provides access to more technical information, such as a glossary, information on <span class="hlt">volcano</span> hydrology, monitoring information, a photo archive, and information on CVO research projects.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2010-09-15</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">271</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008PApGe.165.2143T"> <span id="translatedtitle">Stromboli Island (Italy): Scenarios of Tsunamis Generated by <span class="hlt">Submarine</span> Landslides</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Stromboli is an Italian volcanic island known for its persistent state of activity, which leads to frequent mass failures and consequently to frequent tsunamis ranging from large (and rare) catastrophic events involving the entire southern Tyrrhenian Sea to smaller events with, however, extremely strong local impact. Most of tsunamigenic landslides occur in the Sciara del Fuoco (SdF) zone, which is a deep scar in the NW flank of the <span class="hlt">volcano</span>, that was produced by a Holocene massive flank collapse and that is the accumulation area of all the eruptive ejecta from the craters. Shallow-water bathymetric surveys around the island help one to identify <span class="hlt">submarine</span> canyons and detachment scars giving evidence of mass instabilities and failures that may have produced and might produce tsunamis. The main purpose of this paper is to call attention to tsunami sources in Stromboli that are <span class="hlt">located</span> outside the SdF area. Further, we do not touch on tsunami scenarios associated with gigantic sector collapses that have repeat times in the order of several thousands of years, but rather concentrate on intermediate size tsunamis, such as the ones that occurred in December 2002. Though we cannot omit tsunamis from the zone of the SdF, the main emphasis is on the elaboration of preliminary scenarios for three more possible source areas around Stromboli, namely Punta Lena Sud, Forgia Vecchia and Strombolicchio, with the aim of purposeful contributing to the evaluation of the hazard associated with such events and to increase the knowledge of potential threats affecting Stromboli and the nearby islands of the Aeolian archipelago. The simulations show that tsunami sources outside of the SdF can produce disastrous effects. As a consequence, we recommend that the monitoring system that is presently operating in Stromboli and that is focussed on the SdF source area be extended in order to cover even the other sources. Moreover, a synoptic analysis of the results from all the considered tsunami scenarios leads to a very interesting relation between the tsunami total energy and the landslide potential energy, that could be used as a very effective tool to evaluate the expected tsunami size from estimates of the landslide size.</p> <div class="credits"> <p class="dwt_author">Tinti, Stefano; Zaniboni, Filippo; Pagnoni, Gianluca; Manucci, Anna</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">272</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/56101867"> <span id="translatedtitle">InSAR observation of an arrested dike under Marchena <span class="hlt">volcano</span>, Galapagos Islands: Implications for the magmatic systems of aging basaltic shield <span class="hlt">volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The Western Galapagos Islands are very active shield <span class="hlt">volcanoes</span> with an average eruption rate of 3 eruptions during 10 years. The most active <span class="hlt">volcanoes</span> are <span class="hlt">located</span> on the islands of Isabela and Fernandina. Here we discuss interferometric data of Marchena <span class="hlt">volcano</span> in the Northwestern part of the archipelago. Marchena erupted last in 1991. An 1992-2002 interferogram displays range decrease (uplift)</p> <div class="credits"> <p class="dwt_author">F. Amelung</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">273</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014OcScD..11.1301S"> <span id="translatedtitle">Flow dynamics around downwelling <span class="hlt">submarine</span> canyons</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Flow dynamics around a downwelling <span class="hlt">submarine</span> canyon were analysed with the Massachusetts Institute of Technology general circulation model. Blanes Canyon (Northwest Mediterranean) was used for topographic and initial forcing conditions. Fourteen scenarios were modelled with varying forcing conditions. Rossby number and Burger number were used to determine the significance of Coriolis acceleration and stratification (respectively) and their impacts on flow dynamics. A new non-dimensional parameter (?) was introduced to determine the significance of vertical variations in stratification. Some simulations do see brief periods of upwards displacement of water during the 10 day model period, however, the presence of the <span class="hlt">submarine</span> canyon is found to enhance downwards advection of density in all model scenarios. High Burger numbers lead to negative vorticity and a trapped anticyclonic eddy within the canyon, as well as an increased density anomaly. Low Burger numbers lead to positive vorticity, cyclonic circulation and weaker density anomalies. Vertical variations in stratification affect zonal jet placement. Under the same forcing conditions, the zonal jet is pushed offshore in more uniformly stratified domains. Offshore jet <span class="hlt">location</span> generates upwards density advection away from the canyon, while onshore jets generate downwards density advection everywhere within the model domain. Increasing Rossby values across the canyon axis, as well as decreasing Burger values, increase negative vertical flux at shelf break depth (150 m). Increasing Rossby numbers lead to stronger downwards advection of a passive tracer (nitrate) as well as stronger vorticity within the canyon. Results from previous studies were explained within this new dynamic framework.</p> <div class="credits"> <p class="dwt_author">Spurgin, J. M.; Allen, S. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">274</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/52188368"> <span id="translatedtitle">Chemical evolution of Avachinskiy <span class="hlt">volcano</span> (Kamchatka) during the Holocene</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Avachinsky <span class="hlt">volcano</span> is one of the most active <span class="hlt">volcanoes</span> in the volcanic front of Kamchatka, <span class="hlt">located</span> near Petropavlovsk-Kamchatsky. Previous studies recognized two distinct phases in the Holocene eruptive history of Avachinsky <span class="hlt">volcano</span>: 1) early phase of rare and voluminous andesitic eruptions (7.25-3.5 ky BP) and 2) later phase of frequent eruptions of basaltic andesites associated with the construction of the</p> <div class="credits"> <p class="dwt_author">Stepan Krasheninnikov; Maxim Portnyagin; Liliya Bazanova</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">275</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pbs.org/americanfieldguide/teachers/volcanoes/volcanoes_sum.html"> <span id="translatedtitle">American Field Guide: <span class="hlt">Volcanoes</span>, How Safe Are They?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This website integrates video footage and information with lesson plans and activities to teach students about <span class="hlt">volcanoes</span>. Students learn about some of the most dangerous <span class="hlt">volcanoes</span>, plot <span class="hlt">locations</span>, research hazards, and assess risks presented by <span class="hlt">volcanoes</span>. There are lesson plans for each activity with objectives, videos, pre-activities, materials, and discussion questions. There are worksheets, lists, and assessment pages available to download and links for further information.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">276</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFM.T51D2604E"> <span id="translatedtitle">Pit crater formation and mass-wasting on West Mata <span class="hlt">volcano</span> in 2010-2011 interpreted from repeat bathymetric surveys</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A multibeam bathymetric resurvey of West Mata <span class="hlt">submarine</span> <span class="hlt">volcano</span> in the NE Lau basin in November 2011 has revealed major depth changes in the summit area where explosive boninite eruptions were observed by remotely operated vehicle in 2009. The bathymetry differencing between the December 2010 survey and the November 2011 survey, both made with the EM122 system on the R/V Kilo Moana, reveals some well-defined anomalies. There are two large negative anomalies at the summit and a lesser amplitude but broader area positive anomaly downslope on the eastern flank. The western negative anomaly is basically a deep pit of ~70-80 m right where the Hades eruptive vent was <span class="hlt">located</span> in 2009. The larger, linear negative anomaly to the east appears to be a <span class="hlt">submarine</span> slide that took off part of the preexisting summit ridge and a portion of the upper flank of the <span class="hlt">volcano</span> and extends for more than a kilometer to the east. Downslope and east of that is an elongated area positive anomaly extending about kilometer downslope that likely represents the portion of the slide material that is within the resolution of the multibeam difference grids (~ 5-10 m). A smaller negative anomaly on the west rift zone is less certain because it's <span class="hlt">located</span> on a steeper slope where differencing errors are higher. We also recorded water column acoustic scans over the <span class="hlt">volcano</span>'s summit using the ship's EM122 sonar. The water column data did not show obvious bubble plumes rising from the summit or any of the acoustic dropouts recorded during May 2010 multibeam surveys, the latter of which we interpreted as errors in the sound velocity profile induced by temperature/particle anomalies in the rising plume. Because we know that the <span class="hlt">volcano</span> has cyclic activity and that gas bubbles would be relatively small at this depth (1200 m) and difficult to detect acoustically, our assessment is that the <span class="hlt">volcano</span> appeared to have a reduced output of heat and gas during the one month observation period relative to the 2009-10 observations. We interpret the December 2010 - November 2011 bathymetric changes on West Mata as evidence of an event or events over a year (there was no significant change between May 2010 and December 2010) that culminated in magma withdrawal at the summit vents that in turn may have induced a major slump that removed part of the summit area. For the most clearly-defined area of change on the summit and eastern flank of the <span class="hlt">volcano</span>, the amount of measurable negative change is approximately 2.5 times positive change. This "missing" material can be accounted for by some combination of broader dispersal downslope from the slump and/or radial pyroclastic dispersal from the summit and magma withdrawal. The effect of this event on the summit volcanic/hydrothermal system is not clear because we did not conduct any CTD casts in 2011 and the acoustic data from the water column is ambiguous. Part of the answer may lie in the data from the hydrophone near West Mata that was deployed in 2010 and is slated to be recovered in 2012. We will also be conducting a dive to the summit of West Mata with a remotely operated vehicle. These new data and observations will hopefully provide us the exact timeline for the event or events that occurred in 2011 and provide a view of the current state of the <span class="hlt">volcano</span>.</p> <div class="credits"> <p class="dwt_author">Embley, R. W.; Merle, S. G.; Dziak, R. P.; Rubin, K. H.; Martinez, F.; Crowhurst, P. V.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">277</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013GGG....14.3939C"> <span id="translatedtitle">The 1998 eruption of Axial Seamount: New insights on <span class="hlt">submarine</span> lava flow emplacement from high-resolution mapping</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Axial Seamount, an active <span class="hlt">submarine</span> <span class="hlt">volcano</span> on the Juan de Fuca Ridge at 46°N, 130°W, erupted in January 1998 along 11 km of its upper south rift zone. We use ship-based multibeam sonar, high-resolution (1 m) bathymetry, sidescan sonar imagery, and submersible dive observations to map four separate 1998 lava flows that were fed from 11 eruptive fissures. These new mapping results give an eruption volume of 31 × 106 m3, 70% of which was in the northern-most flow, 23% in the southern-most flow, and 7% in two smaller flows in between. We introduce the concept of map-scale <span class="hlt">submarine</span> lava flow morphology (observed at a scale of hundreds of meters, as revealed by the high-resolution bathymetry), and an interpretive model in which two map-scale morphologies are produced by high effusion-rate eruptions: "inflated lobate flows" are formed near eruptive vents, and where they drain downslope more than 0.5-1.0 km, they transition to "inflated pillow flows." These two morphologies are observed on the 1998 lava flows at Axial. A third map-scale flow morphology that was not produced during this eruption, "pillow mounds," is formed by low effusion-rate eruptions in which pillow lava piles up directly over the eruptive vents. Axial Seamount erupted again in April 2011 and there are remarkable similarities between the 1998 and 2011 eruptions, particularly the <span class="hlt">locations</span> of eruptive vents and lava flow morphologies. Because the 2011 eruption reused most of the same eruptive fissures, 58% of the area of the 1998 lava flows is now covered by 2011 lava.</p> <div class="credits"> <p class="dwt_author">Chadwick, W. W.; Clague, D. A.; Embley, R. W.; Perfit, M. R.; Butterfield, D. A.; Caress, D. W.; Paduan, J. B.; Martin, J. F.; Sasnett, P.; Merle, S. G.; Bobbitt, A. M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">278</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/50343864"> <span id="translatedtitle">Human powered <span class="hlt">submarine</span> propeller design</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">While all parts of a <span class="hlt">submarine</span> contribute to its overall performance, the propeller blade design is often neglected due to the difficulties in analyzing the impact in design changes combined with a lack of previous research in blade designs for the power and speed requirements as dictated by a human powered vehicle. To aid us in the design of our</p> <div class="credits"> <p class="dwt_author">B. Ellis; D. Wacholder</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">279</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/48939913"> <span id="translatedtitle">Hydroplaning and <span class="hlt">submarine</span> debris flows</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Examination of <span class="hlt">submarine</span> clastic deposits along the continental margins reveals the remnants of holocenic or older debris flows with run-out distances up to hundreds of kilometers. Laboratory experiments on subaqueous debris flows, where typically one tenth of a cubic meter of material is dropped down a flume, also show high velocities and long run-out distances compared to subaerial debris flows.</p> <div class="credits"> <p class="dwt_author">Fabio V. De Blasio; Lars Engvik; Carl B. Harbitz; Anders Elverhøi</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">280</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2002ASAJ..111.2415D"> <span id="translatedtitle">Obstacle avoidance sonar for <span class="hlt">submarines</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Advanced Mine Detection Sonar (AMDS) system was designed to operate in poor environments with high biological and/or shallow-water boundary conditions. It provides increased capability for active detection of volume, close-tethered, and bottom mines, as well as <span class="hlt">submarine</span> and surface target active/passive detection for ASW and collision avoidance. It also provides bottom topography mapping capability for precise <span class="hlt">submarine</span> navigation in uncharted littoral waters. It accomplishes this by using advanced processing techniques with extremely narrow beamwidths. The receive array consists of 36 modules arranged in a 15-ft-diameter semicircle at the bottom of the <span class="hlt">submarine</span> sonar dome to form a chin-mounted array. Each module consists of 40 piezoelectric rubber elements. The modules provide the necessary signal conditioning to the element data prior to signal transmission (uplink) through the hull. The elements are amplified, filtered, converted to digital signals by an A/D converter, and multiplexed prior to uplink to the inboard receiver. Each module also has a downlink over which it receives synchronization and mode/gain control. Uplink and downlink transmission is done using fiberoptic telemetry. AMDS was installed on the USS Asheville. The high-frequency chin array for Virginia class <span class="hlt">submarines</span> is based on the Asheville design.</p> <div class="credits"> <p class="dwt_author">Dugas, Albert C.; Webman, Kenneth M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-05-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_13");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a 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showDiv("page_16");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">281</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=volcanic+AND+hazard&id=EJ305892"> <span id="translatedtitle"><span class="hlt">Volcanoes</span>: Nature's Caldrons Challenge Geochemists.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">Reviews various topics and research studies on the geology of <span class="hlt">volcanoes</span>. Areas examined include <span class="hlt">volcanoes</span> and weather, plate margins, origins of magma, magma evolution, United States Geological Survey (USGS) <span class="hlt">volcano</span> hazards program, USGS <span class="hlt">volcano</span> observatories, volcanic gases, potassium-argon dating activities, and <span class="hlt">volcano</span> monitoring strategies.…</p> <div class="credits"> <p class="dwt_author">Zurer, Pamela S.</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">282</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=PIA01455&hterms=PDT&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3D%2522PDT%2522"> <span id="translatedtitle">Elysium Mons <span class="hlt">Volcano</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">On July 4, 1998--the first anniversary of the Mars Pathfinder landing--Mars Global Surveyor's latest images were radioed to Earth with little fanfare. The images received on July 4, 1998, however, were very exciting because they included a rare crossing of the summit caldera of a major martian <span class="hlt">volcano</span>. Elysium Mons is <span class="hlt">located</span> at 25oN, 213oW, in the martian eastern hemisphere. Elysium Mons is one of three large <span class="hlt">volcanoes</span> that occur on the Elysium Rise-- the others are Hecates Tholus (northeast of Elysium Mons) and Albor Tholus (southeast of Elysium Mons). The <span class="hlt">volcano</span> rises about 12.5 kilometers (7.8 miles) above the surrounding plain, or about 16 kilometers (9.9 miles) above the martian datum-- the 'zero' elevation defined by average martian atmospheric pressure and the planet's radius.<p/>Elysium Mons was discovered by Mariner 9 in 1972. It differs in a number of ways from the familiar Olympus Mons and other large <span class="hlt">volcanoes</span> in the Tharsis region. In particular, there are no obvious lava flows visible on the <span class="hlt">volcano</span>'s flanks. The lack of lava flows was apparent from the Mariner 9 images, but the new MOC high resolution image--obtained at 5.24 meters (17.2 feet) per pixel--illustrates that this is true even when viewed at higher spatial resolution.<p/>Elysium Mons has many craters on its surface. Some of these probably formed by meteor impact, but many show no ejecta pattern characteristic of meteor impact. Some of the craters are aligned in linear patterns that are radial to the summit caldera--these most likely formed by collapse as lava was withdrawn from beneath the surface, rather than by meteor impact. Other craters may have formed by explosive volcanism. Evidence for explosive volcanism on Mars has been very difficult to identify from previous Mars spacecraft images. This and other MOC data are being examined closely to better understand the nature and origin of volcanic features on Mars.<p/>The three MOC images, 40301 (red wide angle), 40302 (blue wide angle), and 40303 (high resolution, narrow angle) were obtained on Mars Global Surveyor's 403rd orbit around the planet around 9:58 - 10:05 p.m. PDT on July 2, 1998. The images were received and processed at Malin Space Science Systems (MSSS) around 4:00 p.m. PDT on July 4, 1998.<p/>This image: MOC image 40303, shown at 25% of its original size. North is approximately up, illumination is from the right. Resolution of picture shown here is 21 meters (69 feet) per pixel. Image was received with bright slopes saturated at DN=255.<p/>Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">283</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009IJEaS..98..885D"> <span id="translatedtitle">Cold-water coral banks and <span class="hlt">submarine</span> landslides: a review</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This paper aims to review the relation between cold-water coral bank development and <span class="hlt">submarine</span> landslides. Both are common features on continental margins, but so far it has not been reviewed which effect—if at all—they may have upon each other. Indirect and direct relations between coral banks and landslides are evaluated here, based on four case studies: the Magellan Mound Province in the Porcupine Seabight, where fossil coral banks appear partly on top of a buried slide deposit; the Sula Ridge Reef Complex and the Storegga landslide both off mid-Norway; and the Mauritania coral bank province, associated with the Mauritanian Slide Complex. For each of these <span class="hlt">locations</span>, positive and negative relationships between both features are discussed, based on available datasets. Locally <span class="hlt">submarine</span> landslides might directly favour coral bank development by creating substratum where corals can settle on, enhancing turbulence due to abrupt seabed morphological variations and, in some cases, causing fluid seepage. In turn, some of these processes may contribute to increased food availability and lower sedimentation rates. Landslides can also affect coral bank development by direct erosion of the coral banks, and by the instantaneous increase of turbidity, which may smother the corals. On the other hand, coral banks might have a stabilising function and delay or stop the headwall retrogradation of <span class="hlt">submarine</span> landslides. Although local relationships can be deduced from these case studies, no general and direct relationship exists between <span class="hlt">submarine</span> landslides and cold-water coral banks.</p> <div class="credits"> <p class="dwt_author">de Mol, Ben; Huvenne, Veerle; Canals, Miquel</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">284</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/x736878445jr75x6.pdf"> <span id="translatedtitle">Physical Properties of Muds Extruded from Mud <span class="hlt">Volcanoes</span>: Implications for Episodicity of Eruptions and Relationship to Seismicity</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Scientific drilling into <span class="hlt">submarine</span> mud <span class="hlt">volcanoes</span> on the Mediterranean Ridge accretionary complex has documented episodic eruptive activity over the last 1 to >1.5 million years. Mud extrusion is related to plate convergence between Africa and Eurasia that caused backthrust faulting of accreted strata over the seismically active, rigid backstop of Crete (Greece). The domes consist of mud breccia with up</p> <div class="credits"> <p class="dwt_author">Achim J. Kopf; M. Ben Clennell; Kevin M. Brown</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">285</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011NatGe...4..799R"> <span id="translatedtitle">Active <span class="hlt">submarine</span> eruption of boninite in the northeastern Lau Basin</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Subduction of oceanic crust and the formation of volcanic arcs above the subduction zone are important components in Earth's geological and geochemical cycles. Subduction consumes and recycles material from the oceanic plates, releasing fluids and gases that enhance magmatic activity, feed hydrothermal systems, generate ore deposits and nurture chemosynthetic biological communities. Among the first lavas to erupt at the surface from a nascent subduction zone are a type classified as boninites. These lavas contain information about the early stages of subduction, yet because most subduction systems on Earth are old and well-established, boninite lavas have previously only been observed in the ancient geological record. Here we observe and sample an active boninite eruption occurring at 1,200m depth at the West Mata <span class="hlt">submarine</span> <span class="hlt">volcano</span> in the northeast Lau Basin, southwest Pacific Ocean. We find that large volumes of H2O, CO2 and sulphur are emitted, which we suggest are derived from the subducting slab. These volatiles drive explosive eruptions that fragment rocks and generate abundant incandescent magma-skinned bubbles and pillow lavas. The eruption has been ongoing for at least 2.5 years and we conclude that this boninite eruption is a multi-year, low-mass-transfer-rate eruption. Thus the Lau Basin may provide an important site for the long-term study of <span class="hlt">submarine</span> volcanic eruptions related to the early stages of subduction.</p> <div class="credits"> <p class="dwt_author">Resing, Joseph A.; Rubin, Kenneth H.; Embley, Robert W.; Lupton, John E.; Baker, Edward T.; Dziak, Robert P.; Baumberger, Tamara; Lilley, Marvin D.; Huber, Julie A.; Shank, Timothy M.; Butterfield, David A.; Clague, David A.; Keller, Nicole S.; Merle, Susan G.; Buck, Nathaniel J.; Michael, Peter J.; Soule, Adam; Caress, David W.; Walker, Sharon L.; Davis, Richard; Cowen, James P.; Reysenbach, Anna-Louise; Thomas, Hans</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">286</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2003AGUFM.V11G..06S"> <span id="translatedtitle">Rapid Mass Wasting Following Nearshore Underwater Volcanism on Kilauea <span class="hlt">Volcano</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The rapid mass wasting of shallow <span class="hlt">submarine</span> basalts was documented during SCUBA dives (with extensive underwater video and photography) along the flanks of Kilauea <span class="hlt">volcano</span>, Hawaii during the Ki'i lava entry of the current eruption (19° 20.4'N, 155° 00.0'W). Lava entered the ocean at this site from mid-February to late March 1990, with several pauses. Dives on 19-20 March 1990 confirmed the widespread formation of lava pillows, as well as channelized lava flows, at this site over a water depth range of 20-40 m. Visual observations suggested that the resulting volcanic deposits were generally stable, despite the steep incline of the seafloor ( ˜40 degrees). (The pre-eruptive seafloor slope was ˜14 degrees.) However, dives on 2 April 1990 revealed that nearly all of these relatively large <span class="hlt">submarine</span> volcanic features had been subject to mass wasting, as the offshore area had been transformed into a debris field composed of material ranging in size from fine sand to boulder fragments. This generally featureless seascape extended uniformly to beyond the visual range of divers ( ˜60 m water depth). High resolution side-scan bathymetry and imaging indicate that steeply sloped talus fields extend down the flanks of Kilauea in this area to abyssal depths, implying a possible linkage between coastal <span class="hlt">submarine</span> volcanism and deep-water deposits. This work, combined with other observations at Kilauea, also suggests that coastal <span class="hlt">submarine</span> volcanism may not generally result in the accumulation of stable rock formations.</p> <div class="credits"> <p class="dwt_author">Sansone, F. J.; Smith, J. R.; Culp, J. B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">287</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/354ckqk60uuxv5dx.pdf"> <span id="translatedtitle"><span class="hlt">Submarine</span> silicic volcanism of the Healy caldera, southern Kermadec arc (SW Pacific): I - volcanology and eruption mechanisms</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The <span class="hlt">submarine</span> Healy <span class="hlt">volcano</span> (southern Kermadec arc), with a 2-2.5 km wide caldera, is pervasively mantled with highly vesicular silicic pumice within a water depth of 1,150-1,800 m. Pumices comprise type 1 white-light grey pumice with ⢾ mm vesicles and weak-moderate foliation, type 2 grey pumice with millimetre-scale laminae, flow banded foliation, including stretched vesicles ⣗ mm in length, and</p> <div class="credits"> <p class="dwt_author">Ian C. Wright; John A. Gamble; Phil A. R. Shane</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">288</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40925420"> <span id="translatedtitle">Noble gases in <span class="hlt">submarine</span> pillow basalt glasses from Loihi and Kilauea, Hawaii - A solar component in the Earth</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Noble gas elemental and isotopic abundances have been analyzed in 22 samples of basaltic glass dredged from the <span class="hlt">submarine</span> flanks of two currently active Hawaiian <span class="hlt">volcanoes</span>, Loihi Seamount and Kilauea. Neon isotopic ratios are enriched in Ne-20 and Ne-21 by as much as 16 percent with respect to atmospheric ratios. All the Hawaiian basalt glass samples show relatively high He-3\\/He-4</p> <div class="credits"> <p class="dwt_author">Masahiko Honda; Ian McDougall; Desmond B. Patterson; Anthony Doulgeris; David A. Clague</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">289</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=PIA03880&hterms=Leader+manager&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DLeader%2Bmanager"> <span id="translatedtitle">Soufriere Hills <span class="hlt">Volcano</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">In this ASTER image of Soufriere Hills <span class="hlt">Volcano</span> on Montserrat in the Caribbean, continued eruptive activity is evident by the extensive smoke and ash plume streaming towards the west-southwest. Significant eruptive activity began in 1995, forcing the authorities to evacuate more than 7,000 of the island's original population of 11,000. The primary risk now is to the northern part of the island and to the airport. Small rockfalls and pyroclastic flows (ash, rock and hot gases) are common at this time due to continued growth of the dome at the <span class="hlt">volcano</span>'s summit.<p/>This image was acquired on October 29, 2002 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.<p/>ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.<p/>The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active <span class="hlt">volcanoes</span>; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.<p/>Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Bjorn Eng of JPL is the project manager. The Terra mission is part of NASA's Earth Science Enterprise, a long- term research effort to understand and protect our home planet. Through the study of Earth, NASA will help to provide sound science to policy and economic decision-makers so as to better life here, while developing the technologies needed to explore the universe and search for life beyond our home planet.<p/>Size: 40.5 x 40.5 km (25.1 x 25.1 miles) <span class="hlt">Location</span>: 16.7 deg. North lat., 62.2 deg. West long. Orientation: North at top Image Data: ASTER bands 1,2, and 3. Original Data Resolution: 15 m Date Acquired: October 29, 2002</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">290</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1990JGR....9514325G"> <span id="translatedtitle">Origin and evolution of valleys on Martian <span class="hlt">volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Medium (1:2,000,000) and high (1:500,000) resolution Viking images were used to <span class="hlt">locate</span>, map, and analyze drainage systems of six moderate-sized Martian <span class="hlt">volcanoes</span> of various ages (including Ceraunius Tholus, Hecates Tholus, Alba Patera, Hadriaca Patera, Apollinaris Patera, and Tyrrhena Patera) in order to determine the origin and the evolution of valley forms on these <span class="hlt">volcanoes</span>. The morphological characteristics of the drainage forms were compared to those of terrestrial volcanic valleys of known origin. On the basis of studies of valleys on the Hawaiian <span class="hlt">volcanoes</span>, an evolutionary sequence for valleys on the Martian <span class="hlt">volcanoes</span> is proposed.</p> <div class="credits"> <p class="dwt_author">Gulick, Virginia C.; Baker, Victor R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">291</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=MSFC-0202485&hterms=history+volcanoes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dhistory%2Bvolcanoes"> <span id="translatedtitle">Erupting <span class="hlt">Volcano</span> Mount Etna</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">An Expedition Two crewmember aboard the International Space Station (ISS) captured this overhead look at the smoke and ash regurgitated from the erupting <span class="hlt">volcano</span> Mt. Etna on the island of Sicily, Italy. At an elevation of 10,990 feet (3,350 m), the summit of the Mt. Etna <span class="hlt">volcano</span>, one of the most active and most studied <span class="hlt">volcanoes</span> in the world, has been active for a half-million years and has erupted hundreds of times in recorded history.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">292</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://hvo.wr.usgs.gov/"> <span id="translatedtitle">The Hawaiian <span class="hlt">Volcano</span> Observatory</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">The Hawaiian <span class="hlt">Volcano</span> Observatory (HVO) is part of the <span class="hlt">Volcano</span> Hazards Program of the U.S. Geological Survey. HVO's origins are rooted in a desire to use scientific methodology to understand the nature of volcanic processes and to reduce their risks to society. The website provides eruption histories and updates of Kilauea, Mauna Loa, Lo' ihi and other Hawaiian <span class="hlt">volcanoes</span> as well as earthquake hazards, zoning, and seismicity.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">293</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=PB2011107190"> <span id="translatedtitle">Risk Assessment for <span class="hlt">Submarine</span> Slope Stability: Preliminary Studies and Numerical Modeling of Hydroplaning of <span class="hlt">Submarine</span> Slides.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary"><span class="hlt">Submarine</span> landslides present an important risk to offshore structures and related facilities. Although <span class="hlt">submarine</span> slides have many similarities to their subaerial counterparts, there are important differences. As part of previous OTRC research sponsored by...</p> <div class="credits"> <p class="dwt_author">H. Hu S. G. Wright</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">294</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19920001720&hterms=history+volcanoes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dhistory%2Bvolcanoes"> <span id="translatedtitle">Mud <span class="hlt">volcanoes</span> on Mars?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The term mud <span class="hlt">volcano</span> is applied to a variety of landforms having in common a formation by extrusion of mud from beneath the ground. Although mud is the principal solid material that issues from a mud <span class="hlt">volcano</span>, there are many examples where clasts up to boulder size are found, sometimes thrown high into the air during an eruption. Other characteristics of mud <span class="hlt">volcanoes</span> (on Earth) are discussed. The possible presence of mud <span class="hlt">volcanoes</span>, which are common and widespread on Earth, on Mars is considered.</p> <div class="credits"> <p class="dwt_author">Komar, Paul D.</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">295</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011EOSTr..92Q.187S"> <span id="translatedtitle">Iceland's Grímsvötn <span class="hlt">volcano</span> erupts</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">About 13 months after Iceland's Eyjafjallajökull <span class="hlt">volcano</span> began erupting on 14 April 2010, which led to extensive air traffic closures over Europe, Grímsvötn <span class="hlt">volcano</span> in southeastern took its turn. Iceland's most active <span class="hlt">volcano</span>, which last erupted in 2004 and lies largely beneath the Vatnajökull ice cap, began its eruption activity on 21 May, with the ash plume initially reaching about 20 kilometers in altitude, according to the Icelandic Meteorological Office. Volcanic ash from Grímsvötn has cancelled hundreds of airplane flights and prompted U.S. president Barack Obama to cut short his visit to Ireland. As Eos went to press, activity at the <span class="hlt">volcano</span> was beginning to subside.</p> <div class="credits"> <p class="dwt_author">Showstack, Randy</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">296</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/744k8300523237l7.pdf"> <span id="translatedtitle">A giant three-stage <span class="hlt">submarine</span> slide off Norway</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">One of the largest <span class="hlt">submarine</span> slides known, The Storegga Slide, is <span class="hlt">located</span> on the Norwegian continental margin. The slide is up to 450 m thick and has a total volume of about 5,600 km3. The headwall of the slide scar is 290 km long and the total run-out distance is about 800 km. The slide involved sediments of Quaternary to</p> <div class="credits"> <p class="dwt_author">Tom Bugge; Stein Befring; Robert H. Belderson; Tor Eidvin; Eystein Jansen; Neil H. Kenyon; Hans Holtedahl; Hans Petter Sejrup</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">297</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40159528"> <span id="translatedtitle">Paleomagnetic constraints on eruption patterns at the Pacaya composite <span class="hlt">volcano</span>, Guatemala</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Pacaya <span class="hlt">volcano</span> is an active composite <span class="hlt">volcano</span> <span class="hlt">located</span> in the volcanic highlands of Guatemala about 40 km south of Guatemala City. Volcanism at Pacaya alternates between Strombolian and Vulcanian, and during the past five years there has been a marked increase in the violence of eruptions. The <span class="hlt">volcano</span> is composed principally of basalt flows interbedded with thin scoria fall units,</p> <div class="credits"> <p class="dwt_author">F Michael Conway; Jimmy F Diehl; Otoniel Matías</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">298</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/893885"> <span id="translatedtitle">Decreasing Magmatic Footprints of Individual <span class="hlt">Volcanos</span> in a Waning Basaltic Field</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The distribution and characteristics of individual basaltic <span class="hlt">volcanoes</span> in the waning Southwestern Nevada Volcanic Field provide insight into the changing physical nature of magmatism and the controls on <span class="hlt">volcano</span> <span class="hlt">location</span>. During Pliocene-Pleistocene times the volumes of individual <span class="hlt">volcanoes</span> have decreased by more than one order of magnitude, as have fissure lengths and inferred lava effusion rates. Eruptions evolved from Hawaiian-style eruptions with extensive lavas to eruptions characterized by small pulses of lava and Strombolian to violent Strombolian mechanisms. These trends indicate progressively decreasing partial melting and length scales, or magmatic footprints, of mantle source zones for individual <span class="hlt">volcanoes</span>. The <span class="hlt">location</span> of each <span class="hlt">volcano</span> is determined by the <span class="hlt">location</span> of its magmatic footprint at depth, and only by shallow structural and topographic features that are within that footprint. The <span class="hlt">locations</span> of future <span class="hlt">volcanoes</span> in a waning system are less likely to be determined by large-scale topography or structures than were older, larger volume <span class="hlt">volcanoes</span>.</p> <div class="credits"> <p class="dwt_author">G.A> Valentine; F.V. Perry</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-06-06</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">299</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006AGUFMIN43A0898B"> <span id="translatedtitle"><span class="hlt">Volcano</span> Monitoring Using Google Earth</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">At the Alaska <span class="hlt">Volcano</span> Observatory (AVO), Google Earth is being used as a visualization tool for operational satellite monitoring of the region's <span class="hlt">volcanoes</span>. Through the abilities of the Keyhole Markup Language (KML) utilized by Google Earth, different datasets have been integrated into this virtual globe browser. Examples include the ability to browse thermal satellite image overlays with dynamic control, to look for signs of volcanic activity. Webcams can also be viewed interactively through the Google Earth interface to confirm current activity. Other applications include monitoring the <span class="hlt">location</span> and status of instrumentation; near real-time plotting of earthquake hypocenters; mapping of new volcanic deposits; and animated models of ash plumes within Google Earth, created by a combination of ash dispersion modeling and 3D visualization packages. The globe also provides an ideal interface for displaying near real-time information on detected thermal anomalies or "hotspot"; pixels in satellite images with elevated brightness temperatures relative to the background temperature. The Geophysical Institute at the University of Alaska collects AVHRR (Advanced Very High Resolution Radiometer) and MODIS (Moderate Resolution Imaging Spectroradiometer) through its own receiving station. The automated processing that follows includes application of algorithms that search for hotspots close to <span class="hlt">volcano</span> <span class="hlt">location</span>, flagging those that meet certain criteria. Further automated routines generate folders of KML placemarkers, which are linked to Google Earth through the network link function. Downloadable KML files have been created to provide links to various data products for different <span class="hlt">volcanoes</span> and past eruptions, and to demonstrate examples of the monitoring tools developed. These KML files will be made accessible through a new website that will become publicly available in December 2006.</p> <div class="credits"> <p class="dwt_author">Bailey, J. E.; Dehn, J.; Webley, P.; Skoog, R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">300</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www2.gwu.edu/~nsarchiv/NSAEBB/NSAEBB399/"> <span id="translatedtitle">The Underwater Cuban Missile Crisis: Soviet <span class="hlt">Submarines</span> and the Risk of Nuclear War</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">The folks at The National Security Archive are always up to something interesting, like this recently released electronic briefing book. The site provides users with access to numerous documents related to the activities of Soviet <span class="hlt">submarines</span> during the Cuban Missile Crisis. Visitors can look over the original Soviet Navy map of the Caribbean, which shows the <span class="hlt">locations</span> of the four Foxtrot diesel <span class="hlt">submarines</span> that had deployed from the Kola peninsula northwest of Murmansk on October 1962, bound for Mariel port in Cuba. That's just the tip of the proverbial iceberg: the book also contains images of the diary of <span class="hlt">submariner</span> Anatoly Petrovich Andreyev and video of Captain John Peterson (United States Navy, retired) talking at a conference in 2002 about the hunt for the <span class="hlt">submarines</span>. It's an absolutely engrossing collection and one that will merit several return visits.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_14");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return 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class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_15");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a onClick='return showDiv("page_5");' href="#">5</a> <a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <a onClick='return showDiv("page_8");' href="#">8</a> <a onClick='return 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title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">301</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22366644"> <span id="translatedtitle"><span class="hlt">Submarines</span>, spacecraft and exhaled breath.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Foreword The International Association of Breath Research (IABR) meetings are an eclectic gathering of researchers in the medical, environmental and instrumentation fields; our focus is on human health as assessed by the measurement and interpretation of trace chemicals in human exhaled breath. What may have escaped our notice is a complementary field of research that explores the creation and maintenance of artificial atmospheres practised by the <span class="hlt">submarine</span> air monitoring and air purification (SAMAP) community. SAMAP is comprised of manufacturers, researchers and medical professionals dealing with the engineering and instrumentation to support human life in <span class="hlt">submarines</span> and spacecraft (including shuttlecraft and manned rockets, high-altitude aircraft, and the International Space Station (ISS)). Here, the immediate concerns are short-term survival and long-term health in fairly confined environments where one cannot simply 'open the window' for fresh air. As such, one of the main concerns is air monitoring and the main sources of contamination are CO(2) and other constituents of human exhaled breath. Since the inaugural meeting in 1994 in Adelaide, Australia, SAMAP meetings have been held every two or three years alternating between the North American and European continents. The meetings are organized by Dr Wally Mazurek (a member of IABR) of the Defense Systems Technology Organization (DSTO) of Australia, and individual meetings are co-hosted by the navies of the countries in which they are held. An overriding focus at SAMAP is life support (oxygen availability and carbon dioxide removal). Certainly, other air constituents are also important; for example, the closed environment of a <span class="hlt">submarine</span> or the ISS can build up contaminants from consumer products, cooking, refrigeration, accidental fires, propulsion and atmosphere maintenance. However, the most immediate concern is sustaining human metabolism: removing exhaled CO(2) and replacing metabolized O(2). Another important concern is a suite of products from chemical reactions among oxidizing compounds with biological chemicals such as amines, thiols and carbonyls. SAMAP Meeting We (Armin and Joachim) attended the 2011 SAMAP conference in Taranto, Italy (10-14 October), which occurred just a few weeks after the IABR meeting in Parma, Italy (11-15 September 2011). It was held at the Officers' Club of the Taranto Naval Base under the patronage of the Italian navy; the local host was Lucio Ricciardi of the University of Insubria, Varese, Italy. At the 2011 SAMAP meeting, the theme was air-independent propulsion (AIP), meaning the capability of recharging the main batteries of the <span class="hlt">submarine</span> without the need to surface. Only a few navies (e.g. US, UK, France, Russia, China) have historically had this capability using nuclear-powered <span class="hlt">submarines</span> that can function underwater for extended periods of time (months). Most navies operate <span class="hlt">submarines</span> with conventional diesel-electric propulsion, wherein diesel-powered generators charge battery banks which then drive an electric motor connected to the propeller. The batteries are charged while the boat is on the surface or during snorkelling, when the boat is submerged a few meters below the surface and a snorkel tube is extended to the surface. The period between battery charges can vary from several hours to one or two days depending on the power requirements and the nature of the mission. The process is necessary for breathing air revitalization (flushing out accumulated contaminants) and for the operation of the diesel engines. However, during this period the <span class="hlt">submarine</span> is vulnerable to detection. Since the 1940s there have been various attempts to develop a power generation system that is independent of external air (AIP). To this end hydrogen peroxide was initially used and later liquid oxygen (LOX). Currently, most AIP <span class="hlt">submarines</span> use fuel cell technology (LOX and hydrogen) to supplement the conventional diesel-electric system in order to extend the underwater endurance to 2-3 weeks. These propulsion engineering changes also reduce per</p> <div class="credits"> <p class="dwt_author">Pleil, Joachim D; Hansel, Armin</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">302</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008AGUFM.V43A2143S"> <span id="translatedtitle">Ambient Noise Tomography at Bezymianny <span class="hlt">Volcano</span>, Kamchatka</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Bezymianny <span class="hlt">Volcano</span> is an active stratovolcano <span class="hlt">located</span> in the Kluychevskoy volcanic group on the Kamchatka Peninsula in eastern Russia. Since its dramatic sector collapse eruption in 1956, the <span class="hlt">volcano</span>'s activity has been characterized by nearly twice annual plinian eruptions accompanying ongoing lava-dome growth. Its frequent eruptions and similarity to Mt. St. Helens have made it the target of a multifaceted geologic and geophysical project supported by the NSF Partners in Research and Education (PIRE) program. Since mid- 2006, the <span class="hlt">volcano</span> has been monitored by a broadband seismic array that is currently composed of 8 stations within 10 kilometers of the active dome. In this project, we use continuous data from these stations to investigate the static and dynamic structure of the <span class="hlt">volcano</span>. Using methods similar to those used by Brenguier et al. (2007, 2008), we estimate the Green's function for each pair of stations by cross-correlating day-long time series of ambient noise. Paths with high signal-to-noise ratios can be used to estimate group velocity dispersion curves. From these measurements, we work towards constructing the first velocity model of this <span class="hlt">volcano</span>. Furthermore, we begin to test whether measurements of ambient noise can be used to monitor changes inside the <span class="hlt">volcano</span> prior to eruptive activity. These problems will continue to be addressed as more data becomes available in future field seasons.</p> <div class="credits"> <p class="dwt_author">Shuler, A. E.; Ekström, G.; West, M.; Senyukov, S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">303</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2003GGG.....4.8511H"> <span id="translatedtitle">Genovesa <span class="hlt">Submarine</span> Ridge: A manifestation of plume-ridge interaction in the northern Galápagos Islands</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Despite its circular coastline and calderas, Genovesa Island, <span class="hlt">located</span> between the central Galapagos Platform and the Galapagos Spreading Center, is crosscut by both eruptive and noneruptive fissures trending NE-SW. The 075° bearing of the fissures parallels that of Genovesa Ridge, a 55 km long volcanic rift zone that is the most prominent <span class="hlt">submarine</span> rift in the Galapagos and constitutes the majority of the volume of the Genovesa magmatic complex. Genovesa Ridge was the focus of detailed multibeam and side-scan sonar surveys during the Revelle/Drift04 cruise in 2001. The ridge consists of three left stepping en echelon segments; the abundances of lava flows, volcanic terraces, and eruptive cones are all consistent with constructive volcanic processes. The nonlinear arrangement of eruptive vents and the ridge's en echelon structure indicate that it did not form over a single dike. Major and trace element compositions of Genovesa Ridge glasses are modeled by fractional crystallization along the same liquid line of descent as the island lavas, but some of the glasses exhibit higher Mg # than material sampled from the island. Most of the <span class="hlt">submarine</span> and the subaerial lavas have accumulated plagioclase. Incompatible trace element abundances of dredged Genovesa Ridge rocks are lower than the island's lavas, but ratios of the elements are similar in the two settings, which suggests that the island and ridge lavas are derived from nearly identical mantle sources. Glass inclusions in plagioclase phenocrysts from the ridge are compositionally diverse, with both higher and lower MgO than the matrix glass, indicative of homogenization at shallow levels. The structural and geochemical observations are best reconciled if Genovesa Ridge did not form in response to injection of magma laterally from a hot spot-supplied central <span class="hlt">volcano</span>, like Kilauea's Puna Ridge. Instead, Genovesa Ridge and its western extension are the result of passive upwelling directed by far-field tectonic stresses that are generated by tension across the 91°W transform. The proximity of the plume causes magmatism in the extensional zones where it would not ordinarily occur.</p> <div class="credits"> <p class="dwt_author">Harpp, Karen S.; Fornari, Daniel J.; Geist, Dennis J.; Kurz, Mark D.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">304</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=PIA11081&hterms=dominant+colors&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Ddominant%2Bcolors"> <span id="translatedtitle">Chaiten <span class="hlt">Volcano</span>, Chile</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary"><p/> On May 2, 2008 Chile's Chaiten <span class="hlt">Volcano</span> erupted after 9,000 years of inactivity. Now, 4 weeks later, the eruption continues, with ash-, water-, and sulfur-laden plumes blowing hundreds of kilometers to the east and north over Chile and Argentina. On May 24, ASTER captured a day-night pair of thermal infrared images of the eruption, displayed here in enhanced, false colors. At the time of the daytime acquisition (left image) most of the plume appears dark blue because it is too thick for upwelling ground radiation to penetrate. At the edges it appears orange, indicating the presence of ash and sulfur dioxide. In the nighttime image (right), the plume is orange and red near the source, and becomes more yellow-orange further away from the vent. The possible cause is that ash is settling out of the plume further downwind, revealing the dominant presence of sulfur dioxide. <p/> The images were acquired May 24, 2008, cover an area of 37 x 26.5 km, and are <span class="hlt">located</span> near 42.7 degrees south latitude, 72.7 degrees west longitude. <p/> The U.S. science team is <span class="hlt">located</span> at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">305</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014EGUGA..16.7691E"> <span id="translatedtitle">Investigating the active hydrothermal field of Kolumbo <span class="hlt">Volcano</span> using CTD profiling</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The <span class="hlt">submarine</span> Kolumbo <span class="hlt">volcano</span> NE of Santorini Island and the unique active hydrothermal vent field on its crater field (depth ~ 500 m) have been recently explored in multiple cruises aboard E/V Nautilus. ROV explorations showed the existence of extensive vent activity and almost completely absence of vent-specific macrofauna. Gas discharges have been found to be 99%-rich in CO2, which is sequestered at the bottom of the crater due to a special combination of physicochemical and geomorphological factors. The dynamic conditions existing along the water column in the crater have been studied in detail by means of temperature, salinity and conductivity depth profiles for the first time. CTD sensors aboard the ROV Hercules were employed to record anomalies in those parameters in an attempt to investigate several active and inactive vent <span class="hlt">locations</span>. Temporal CTD monitoring inside and outside of the crater was carried out over a period of two years. Direct comparison between the vent field and <span class="hlt">locations</span> outside the main cone, where no hydrothermal activity is known to exist, showed completely different characteristics. CTD profiles above the active vent field (NNE side) are correlated to Kolumbo's cone morphology. The profiles suggest the existence of four distinct zones of physicochemical properties in the water column. The layer directly above the chimneys exhibit gas discharges highly enriched in CO2. Continuous gas motoring is essential to identify the onset of geological hazards in the region.</p> <div class="credits"> <p class="dwt_author">Eleni Christopoulou, Maria; Mertzimekis, Theo; Nomikou, Paraskevi; Papanikolaou, Dimitrios; Carey, Steve</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">306</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.teachersdomain.org/resource/ess05.sci.ess.earthsys.nyiragongo/"> <span id="translatedtitle">Anatomy of a <span class="hlt">Volcano</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This interactive lesson from NOVA Online provides a detailed look at the inner workings of one of the world's most dangerous <span class="hlt">volcanoes</span>, Nyiragongo in the Democratic Republic of Congo. Users can click on highlighted points on a crossection of the <span class="hlt">volcano</span> to see photos and read about its features and eruptive products.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2010-12-14</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">307</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011JVGR..206...61J"> <span id="translatedtitle"><span class="hlt">Volcano</span> infrasound: A review</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Exploding <span class="hlt">volcanoes</span>, which produce intense infrasound, are reminiscent of the veritable explosion of <span class="hlt">volcano</span> infrasound papers published during the last decade. <span class="hlt">Volcano</span> infrasound is effective for tracking and quantifying eruptive phenomena because it corresponds to activity occurring near and around the volcanic vent, as opposed to seismic signals, which are generated by both surface and internal volcanic processes. As with seismology, infrasound can be recorded remotely, during inclement weather, or in the dark to provide a continuous record of a <span class="hlt">volcano</span>'s unrest. Moreover, it can also be exploited at regional or global distances, where seismic monitoring has limited efficacy. This paper provides a literature overview of the current state of the field and summarizes applications of infrasound as a tool for better understanding volcanic activity. Many infrasound studies have focused on integration with other geophysical data, including seismic, thermal, electromagnetic radiation, and gas spectroscopy and they have generally improved our understanding of eruption dynamics. Other work has incorporated infrasound into <span class="hlt">volcano</span> surveillance to enhance capabilities for monitoring hazardous <span class="hlt">volcanoes</span> and reducing risk. This paper aims to provide an overview of <span class="hlt">volcano</span> airwave studies (from analog microbarometer to modern pressure transducer) and summarizes how infrasound is currently used to infer eruption dynamics. It also outlines the relative merits of local and regional infrasound surveillance, highlights differences between array and network sensor topologies, and concludes with mention of sensor technologies appropriate for <span class="hlt">volcano</span> infrasound study.</p> <div class="credits"> <p class="dwt_author">Johnson, Jeffrey Bruce; Ripepe, Maurizio</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">308</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://volcanoes.usgs.gov/about/edu/"> <span id="translatedtitle"><span class="hlt">Volcano</span> Resources for Educators</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This site provides an up-to-date list of textual and video educational materials pertaining to <span class="hlt">volcanoes</span>. The online pamphlets and books, hardcopy books, rental films and videos cover all levels of interest regarding <span class="hlt">volcanoes</span>. The site furnishes the information or links to information needed to obtain these materials.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">309</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.avo.alaska.edu/index.php"> <span id="translatedtitle">Alaska <span class="hlt">Volcano</span> Observatory</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This is the homepage of the Alaska <span class="hlt">Volcano</span> Observatory, a joint program of the United States Geological Survey (USGS), the Geophysical Institute of the University of Alaska Fairbanks (UAFGI), and the State of Alaska Division of Geological and Geophysical Surveys (ADGGS). Users can access current information on volcanic activity in Alaska and the Kamchatka Penninsula, including weekly and daily reports and information releases about significant changes in any particluar <span class="hlt">volcano</span>. An interactive map also directs users to summaries and activity notifications for selected <span class="hlt">volcanoes</span>, or through links to webcams and webicorders (recordings of seismic activity). General information on Alaskan <span class="hlt">volcanoes</span> includes descriptions, images, maps, bibliographies, and eruptive histories. This can be accessed through an interactive map or by clicking on an alphabetic listing of links to individual <span class="hlt">volcanoes</span>. There is also an online library of references pertinent to Quaternary volcanism in Alaska and an image library.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">310</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009DSRI...56.1336W"> <span id="translatedtitle">The ecology and distribution of benthic foraminifera at the Håkon Mosby mud <span class="hlt">volcano</span> (SW Barents Sea slope)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">To investigate a possible influence of <span class="hlt">submarine</span> methane seepage on benthic foraminiferal communities, Rose Bengal stained ("live") and empty tests of benthic foraminifera were studied from the sediment surface down to 15 cm sub-bottom depth of 12 sites at the Håkon Mosby mud <span class="hlt">volcano</span> (HMMV). In addition, one reference site well away from the seep sites, but from similar water depths and the same general hydrographic setting was occupied for comparison. The HMMV is <span class="hlt">located</span> at 1265 m water depth on the SW Barents Sea continental slope. Distinct living foraminiferal associations at the HMMV are linked to specific sedimentary, microbial, and macrofaunal habitats. In the center of the crater, and in crater areas completely covered by bacterial mats, Cassidulina reniforme is the only, albeit rare, living species. Below the top few millimeters, sediments are anoxic and devoid of living specimens. At the rim of the mud <span class="hlt">volcano</span>, at sites densely populated by pogonophoran tube worms, three benthic foraminiferal associations are found; (i) a Fontbotia wuellerstorfi-Lobatula lobatula association living attached to the upper parts of pogonophoran tubes, which protrude into oxic water, (ii) a diverse Cassidulina neoteretis association populating dysoxic sediments of the surface centimeter, and (iii) a species-poor Bolivina pseudopunctata association colonizing the subsurface sediments down to four centimeters. Generally, we did not find endemic or seep indicative species or associations at the HMMV. However, the HMMV live faunas dominated by B. pseudopunctata are not found at the reference site nor are they described from comparable water depths and environments without gas seepages from the Norwegian-Greenland Seas. In the center and outer rim of the mud <span class="hlt">volcano</span>, a C. neoteretis-Reophax guttifer dead association, similar to the one at the reference site, characterizes an assemblage of strongly corroded and partly displaced tests. At bacterial mat sites, a C. reniforme dead association corresponds to the living one. Thus both the living and the dead associations are indicative of a specific bacterial mat environment at the HMMV.</p> <div class="credits"> <p class="dwt_author">Wollenburg, J. E.; Mackensen, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">311</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/5313127"> <span id="translatedtitle">Flank tectonics of Martian <span class="hlt">volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">On the flanks of Olympus Mons is a series of terraces, concentrically distributed around the caldera. Their morphology and <span class="hlt">location</span> suggest that they could be thrust faults caused by compressional failure of the cone. In an attempt to understand the mechanism of faulting and the possible influences of the interior structure of Olympus Mons, the authors have constructed a numerical model for elastic stresses within a Martian <span class="hlt">volcano</span>. In the absence of internal pressurization, the middle slopes of the cone are subjected to compressional stress, appropriate to the formation of thrust faults. These stresses for Olympus Mons are {approximately}250 MPa. If a vacant magma chamber is contained within the cone, the region of maximum compressional stress is extended toward the base of the cone. If the magma chamber is pressurized, extensional stresses occur at the summit and on the upper slopes of the cone. For a filled but unpressurized magma chamber, the observed positions of the faults agree well with the calculated region of high compressional stress. Three other <span class="hlt">volcanoes</span> on Mars, Ascraeus Mons, Arsia Mons, and Pavonis Mons, possess similar terraces. Extending the analysis to other Martian <span class="hlt">volcanoes</span>, they find that only these three and Olympus Mons have flank stresses that exceed the compressional failure strength of basalt, lending support to the view that the terraces on all four are thrust faults.</p> <div class="credits"> <p class="dwt_author">Thomas, P.J. (Univ. of Wisconsin, Eau Claire (USA)); Squyres, S.W. (Cornell Univ., Ithaca, NY (USA)); Carr, M.H. (Geological Survey, Menlo Park, CA (USA))</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-08-30</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">312</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=PIA01910&hterms=volcanoes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2522volcanoes%2522"> <span id="translatedtitle">Northern Arizona <span class="hlt">Volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary"><p/> Northern Arizona is best known for the Grand Canyon. Less widely known are the hundreds of geologically young <span class="hlt">volcanoes</span>, at least one of which buried the homes of local residents. San Francisco Mtn., a truncated stratovolcano at 3887 meters, was once a much taller structure (about 4900 meters) before it exploded some 400,000 years ago a la Mt. St. Helens. The young cinder cone field to its east includes Sunset Crater, that erupted in 1064 and buried Native American homes. This ASTER perspective was created by draping ASTER image data over topographic data from the U.S. Geological Survey National Elevation Data. <p/> With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet. <p/> ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. <p/> The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active <span class="hlt">volcanoes</span>; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance. <p/> The U.S. science team is <span class="hlt">located</span> at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate. <p/> Size: 20.4 by 24.6 kilometers (12.6 by 15.2 miles) <span class="hlt">Location</span>: 35.3 degrees North latitude, 111.5 degrees West longitude Orientation: North at top Image Data: ASTER Bands 3, 2, and 1 Original Data Resolution: Landsat 30 meters (24.6 feet); ASTER 15 meters (49.2 feet) Dates Acquired: October 21, 2003</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">313</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70014306"> <span id="translatedtitle">Gravity model studies of Newberry <span class="hlt">Volcano</span>, Oregon</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Newberry <span class="hlt">Volcano</span>, a large Quaternary <span class="hlt">volcano</span> <span class="hlt">located</span> about 60 km east of the axis of the High Cascades <span class="hlt">volcanoes</span> in central Oregon, has a coincident positive residual gravity anomaly of about 12 mGals. Model calculations of the gravity anomaly field suggest that the <span class="hlt">volcano</span> is underlain by an intrusive complex of mafic composition of about 20-km diameter and 2-km thickness, at depths above 4 km below sea level. However, uplifted basement in a northwest trending ridge may form part of the underlying excess mass, thus reducing the volume of the subvolcanic intrusive. A ring dike of mafic composition is inferred to intrude to near-surface levels along the caldera ring fractures, and low-density fill of the caldera floor probably has a thickness of 0.7-0.9 km. The gravity anomaly attributable to the <span class="hlt">volcano</span> is reduced to the east across a north-northwest trending gravity anomaly gradient through Newberry caldera and suggests that normal, perhaps extensional, faulting has occurred subsequent to caldera formation and may have controlled the <span class="hlt">location</span> of some late-stage basaltic and rhyolitic eruptions. Significant amounts of felsic intrusive material may exist above the mafic intrusive zone but cannot be resolved by the gravity data. -Authors</p> <div class="credits"> <p class="dwt_author">Gettings, M. E.; Griscom, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1988-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">314</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dx.doi.org/10.1016/S0169-555X(01)00065-4"> <span id="translatedtitle">Mud <span class="hlt">volcanoes</span> of the Orinoco Delta, Eastern Venezuela</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Mud <span class="hlt">volcanoes</span> along the northwest margin of the Orinoco Delta are part of a regional belt of soft sediment deformation and diapirism that formed in response to rapid foredeep sedimentation and subsequent tectonic compression along the Caribbean-South American plate boundary. Field studies of five mud <span class="hlt">volcanoes</span> show that such structures consist of a central mound covered by active and inactive vents. Inactive vents and mud flows are densely vegetated, whereas active vents are sparsely vegetated. Four out of the five mud <span class="hlt">volcanoes</span> studied are currently active. Orinoco mud flows consist of mud and clayey silt matrix surrounding lithic clasts of varying composition. Preliminary analysis suggests that the mud <span class="hlt">volcano</span> sediment is derived from underlying Miocene and Pliocene strata. Hydrocarbon seeps are associated with several of the active mud <span class="hlt">volcanoes</span>. Orinoco mud <span class="hlt">volcanoes</span> overlie the crest of a mud-diapir-cored anticline <span class="hlt">located</span> along the axis of the Eastern Venezuelan Basin. Faulting along the flank of the Pedernales mud <span class="hlt">volcano</span> suggests that fluidized sediment and hydrocarbons migrate to the surface along faults produced by tensional stresses along the crest of the anticline. Orinoco mud <span class="hlt">volcanoes</span> highlight the proximity of this major delta to an active plate margin and the importance of tectonic influences on its development. Evaluation of the Orinoco Delta mud <span class="hlt">volcanoes</span> and those elsewhere indicates that these features are important indicators of compressional tectonism along deformation fronts of plate margins. ?? 2001 Elsevier Science B.V. All rights reserved.</p> <div class="credits"> <p class="dwt_author">Aslan, A.; Warne, A. G.; White, W. A.; Guevara, E. H.; Smyth, R. C.; Raney, J. A.; Gibeaut, J. C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">315</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014EGUGA..16.1243J"> <span id="translatedtitle">Seismic unrest at Katla <span class="hlt">Volcano</span>- southern Iceland</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Katla <span class="hlt">volcano</span> is <span class="hlt">located</span> on the propagating Eastern Volcanic Zone (EVZ) in South Iceland. It is <span class="hlt">located</span> beneath Mýrdalsjökull ice-cap which covers an area of almost 600 km2, comprising the summit caldera and the eruption vents. 20 eruptions between 930 and 1918 with intervals of 13-95 years are documented at Katla which is one of the most active subglacial <span class="hlt">volcanoes</span> in Iceland. Eruptions at Katla are mainly explosive due to the subglacial mode of extrusion and produce high eruption columns and catastrophic melt water floods (jökulhlaups). The present long Volcanic repose (almost 96 years) at Katla, the general unrest since 1955, and the 2010 eruption of the neighbouring Eyjafjallajökull <span class="hlt">volcano</span> has prompted concerns among geoscientists about an imminent eruption. Thus, the <span class="hlt">volcano</span> has been densely monitored by seismologists and volcanologists. The seismology group of Uppsala University as a partner in the <span class="hlt">Volcano</span> Anatomy (VA) project in collaboration with the University of Iceland and the Icelandic Meteorological Office (IMO) installed 9 temporary seismic stations on and around the Mýrdalsjökull glacier in 2011. Another 10 permanent seismic stations are operated by IMO around Katla. The project's data collection is now finished and temporary stations were pulled down in August 2013. According to seismicity maps of the whole recording period, thousands of microearthquakes have occurred within the caldera region. At least three different source areas are active in Katla: the caldera region, the western Godaland region and a small cluster at the southern rim of Mýrdalsjökull near the glacial stream of Hafursarjökull. Seismicity in the southern flank has basically started after June 2011. The caldera events are mainly <span class="hlt">volcano</span>-tectonic, while western and southern events are mostly long period (lp) and can be related to glacial or magmatic movement. One motivation of the VA Katla project is to better understand the physical mechanism of these lp events. Changes in seismicity arising from magma movement in the crust are characteristic properties of almost all active <span class="hlt">volcanoes</span>. Meanwhile the study of the seismicity and propagation of elastic waves through the earth have the potential to give us important information about the internal structure of <span class="hlt">volcanoes</span>. As very little is known of the 3D structure of Katla <span class="hlt">volcano</span> and in order to define the 3D velocity structure and the geometry of the possible magma chamber, both P and S-wave travel time data from the most active period of seismicity (July-November 2011) are inverted simultaneously for both hypocenter <span class="hlt">locations</span> and 3D velocity structure by using Local Earthquake Tomography (LET).</p> <div class="credits"> <p class="dwt_author">jeddi, zeinab; Tryggvason, Ari; Gudmundsson, Olafur; Bödvarsson, Reynir; SIL Seismology group</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">316</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40425577"> <span id="translatedtitle"><span class="hlt">Submarine</span> slopes with an exponential curvature</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The curvature of <span class="hlt">submarine</span> slopes is a little used source of information on transport processes and sediment composition. In a survey of modern <span class="hlt">submarine</span> slopes selected from all over the world, about 15% are characterized by very regular profiles with sharp shelfbreaks and concave-upward curvature. An exponential function describes this morphology very well. These exponential profiles are from three very</p> <div class="credits"> <p class="dwt_author">Erwin W. Adams; Wolfgang Schlager; Evert Wattel</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">317</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/5940530"> <span id="translatedtitle"><span class="hlt">Submarine</span> landslide geomorphology, US continental slope</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The morphometric analysis of <span class="hlt">submarine</span> landslides in four distinctly different tectonic environments on the continental slopes of Oregon, central California, Texas, and New Jersey provides useful insight into <span class="hlt">submarine</span> process, including sediment transport mechanisms and slope stability. Using Geographic Information System (GIS) software, we identify landslides from multibeam bathymetric and GLORIA sidescan surveys based solely on surficial morphology and reflectivity.</p> <div class="credits"> <p class="dwt_author">B. g. Mcadoo; L. f. Pratson; D. l. Orange</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">318</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/57624795"> <span id="translatedtitle">Reactivity Accident of Nuclear <span class="hlt">Submarine</span> near Vladivostok</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">After the collapse of the Soviet Union and consequently the termination of the Cold War and the disarmament agreements, many nuclear warheads are in a queue for dismantling. As a result, substantial number of nuclear <span class="hlt">submarines</span> equipped with ballistic missiles will be also withdrawn from service. However, Russian nuclear <span class="hlt">submarines</span> have suffered from reactivity accidents five times. In the paper,</p> <div class="credits"> <p class="dwt_author">Makoto TAKANO; Vanya ROMANOVA; Hiromi YAMAZAWA; Yuri SIVINTSEV; Keith COMPTON; Vladimir NOVIKOV; Frank PARKER</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">319</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=PIA03514&hterms=russia&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Drussia"> <span id="translatedtitle">Shiveluch <span class="hlt">Volcano</span>, Kamchatka Peninsula, Russia</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary"><p/>On the night of June 4, 2001, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) captured this thermal image of the erupting Shiveluch <span class="hlt">volcano</span>. <span class="hlt">Located</span> on Russia's Kamchatka Peninsula, Shiveluch rises to an altitude of 2,447 meters (8,028 feet). The active lava dome complex is seen as a bright (hot) area on the summit of the <span class="hlt">volcano</span>. To the southwest, a second hot area is either a debris avalanche or hot ash deposit. Trailing to the west is a 25-kilometer (15-mile) ash plume, seen as a cold 'cloud' streaming from the summit. At least 60 large eruptions have occurred here during the last 10,000 years; the largest historical eruptions were in 1854 and 1964.<p/>Because Kamchatka is <span class="hlt">located</span> along the major aircraft routes between North America/Europe and Asia, this area is constantly monitored for potential ash hazards to aircraft. The area is part of the 'Ring of Fire,' a string of <span class="hlt">volcanoes</span> that encircles the Pacific Ocean.<p/>The lower image is the same as the upper, except it has been color-coded: red is hot, light greens to dark green are progressively colder, and gray/black are the coldest areas.<p/>The image is <span class="hlt">located</span> at 56.7 degrees north latitude, 161.3 degrees east longitude. <p/>ASTER is one of five Earth-observing instruments launched Dec. 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">320</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.usgs.gov/fs/2000/fs118-00/"> <span id="translatedtitle">Historically Active <span class="hlt">Volcanoes</span> in Alaska - A Quick Reference</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This United States Geological Survey (USGS) fact sheet summarizes historical data (from 1760 to 1999) on 41 Alaskan <span class="hlt">volcanoes</span>, using information drawn from the more thorough and comprehensive USGS Open-File Report 98-582. Summaries include the <span class="hlt">volcano</span> type, <span class="hlt">location</span> (latitude and longitude), <span class="hlt">location</span> on USGS quadrangle map, and any information available about the dates of eruptions and type of volcanic activity that occurred. Some <span class="hlt">volcanoes</span> covered include Trident, Redoubt, Wrangell, Katmai, Cleveland, Kiska and more. A downloadable, printable version is available.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_15");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return 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src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">321</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dx.doi.org/10.1029/2008JC004992"> <span id="translatedtitle">Currents in monterey <span class="hlt">submarine</span> canyon</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Flow fields of mean, subtidal, and tidal frequencies between 250 and 3300 m water depths in Monterey <span class="hlt">Submarine</span> Canyon are examined using current measurements obtained in three yearlong field experiments. Spatial variations in flow fields are mainly controlled by the topography (shape and width) of the canyon. The mean currents flow upcanyon in the offshore reaches (>1000 m) and downcanyon in the shallow reaches (100-m amplitude isotherm oscillations and associated high-speed rectilinear currents. The 15-day spring-neap cycle and a ???3-day??? band are the two prominent frequencies in subtidal flow field. Neither of them seems directly correlated with the spring-neap cycle of the sea level.</p> <div class="credits"> <p class="dwt_author">Xu, J. P.; Noble, M. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">322</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006AGUFM.V23A0590G"> <span id="translatedtitle">New Insights on <span class="hlt">Submarine</span> Volcanism in the Western Galapagos Archipelago from High Resolution Sonar and Magnetic Surveys</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We combine high-resolution MR-1 sidescan sonar and EM-300 bathymetric data collected on four cruises (AHA-Nemo2 in 2000 (R/V Melville), DRIFT4 in 2001 (R/V Revelle), TN188 and TN189 in January 2006 (R/V Thompson) to study volcanic platform-building processes on the <span class="hlt">submarine</span> flanks of Fernandina, Isabela, Roca Redonda and Santiago <span class="hlt">volcanoes</span>, in the western Galapagos. Three primary volcanic provinces were identified including: rift zones (16, ranging from 5 to 20 km in length), small <span class="hlt">submarine</span> volcanic cones (<3 km in diameter and several 100 m high) and deep (>3000 m), long (>10 km), large-area <span class="hlt">submarine</span> lava flows. Lengths of the Galapagos rift zones are comparable to western Canary Island rift zones, but significantly shorter than Hawaiian <span class="hlt">submarine</span> rift zones, possibly reflecting lower magma supply. A surface-towed magnetic survey was conducted over the NW Fernandina rift on TN189 and Fourier inversions were performed to correct for topographic effects. Calculated magnetization was highest (up to +32 A/m) over the shallow southwest flank of the rift, coinciding with cone fields and suggesting most recent volcanism has focused at this portion of the rift. Small <span class="hlt">submarine</span> volcanic cones with various morphologies (e.g., pointed, cratered and occasionally breached) are common in the <span class="hlt">submarine</span> western Galapagos both on rift zones and on the island flanks where no rifts are present, such as the northern flank of Santiago Island. Preliminary study of these cones suggests that their morphologies and depth of occurrence may reflect a combination of petrogenetic and eruption processes. Deep, long large-area lava flow fields in regions of low bathymetric relief have been previously identified as a common seafloor feature in the western Galapagos by Geist et al. [in press], and new EM300 data show that a number of the deep lava flows originate from small cones along the mid-lower portion of the NW <span class="hlt">submarine</span> rift of Fernandina. Our high-resolution sonar data suggest that <span class="hlt">submarine</span> volcanism in the western Galapagos occurs both on and off rift zones. Volcanic cones are prevalent on the Galapagos volcanic platform and long lava flows dominate in the deep regions west and north of the platform, possibly representing the foundation upon which the next Galapagos <span class="hlt">volcanoes</span> will be constructed.</p> <div class="credits"> <p class="dwt_author">Glass, J. B.; Fornari, D. J.; Tivey, M. A.; Hall, H. F.; Cougan, A. A.; Berkenbosch, H. A.; Holmes, M. L.; White, S. M.; de La Torre, G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">323</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008AGUFM.V11A2001L"> <span id="translatedtitle"><span class="hlt">Submarine</span> Hydrothermal Activity on the Aeolian Arc: New Evidence from Helium Isotopes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In November 2007 we conducted a water-column and seafloor mapping study of the <span class="hlt">submarine</span> <span class="hlt">volcanoes</span> of the Aeolian Arc in the southern Tyrrhenian Sea aboard the R/V Urania. A total of 26 CTD casts were completed, 13 vertical casts and 13 tows. In addition to in situ measurements of temperature, conductivity, pressure and suspended particles, we also collected discrete samples for helium isotopes, methane, and trace metals. The helium isotope ratio, which is known to be an unambiguous indicator of hydrothermal input, showed a clear excess above background at 5 out of the 10 <span class="hlt">submarine</span> <span class="hlt">volcanoes</span> surveyed. We found the strongest helium anomaly over Marsili seamount, where the 3He/4He ratio reached maximum values of ?3He = 23% at 610 m depth compared with background values of ~7%. We also found smaller but distinct ?3He anomalies over Enerato, Eolo, Palinuro, and Secca del Capo. We interpret these results as indicating the presence of hydrothermal activity on these 5 seamounts. Hydrothermal venting has been documented at subsea vents offshore of the islands of Panarea, Stromboli, and Vulcano (Dando et al., 1999; Di Roberto et al., 2008), and hydrothermal deposits have been sampled on many of the <span class="hlt">submarine</span> <span class="hlt">volcanoes</span> of the Aeolian Arc (Dekov and Savelli, 2004). However, as far as we know this is the first evidence of present day hydrothermal activity on Marsili, Enerato, and Eolo. Samples collected over Filicudi, Glabro, Lamentini, Sisifo, and Alcioni had ?3He very close to the regional background values, suggesting either absence of or very weak hydrothermal activity on these seamounts. Helium isotope measurements from the background hydrocasts positioned between the <span class="hlt">volcanoes</span> revealed the presence of an excess in 3He throughout the SE Tyrrhenian Sea. These background profiles reach a consistent maximum of about ?3He = 11% at 2300 m depth. Historical helium profiles collected in the central and northern Tyrrhenian Sea in 1987 and 1997 do not show this deep 3He maximum (W. Roether and B. Klein, private comm.). Furthermore, the maximum is too deep to be attributed to the <span class="hlt">volcanoes</span> of the Aeolian Arc, which are active at <1000 m depth. We are currently conducting additional measurements to determine whether this deep 3He maximum is from a local hydrothermal source or is somehow related to the deep water mass transient which occurred in the eastern Mediterranean in the 1990's.</p> <div class="credits"> <p class="dwt_author">Lupton, J.; de Ronde, C.; Baker, E.; Sprovieri, M.; Bruno, P.; Italiano, F.; Walker, S.; Faure, K.; Leybourne, M.; Britten, K.; Greene, R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">324</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19740052372&hterms=hot+Volcanos&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dhot%2BVolcanos"> <span id="translatedtitle">Hot spot and trench <span class="hlt">volcano</span> separations</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">It is suggested that the distribution of separations between trench <span class="hlt">volcanos</span> <span class="hlt">located</span> along subduction zones reflects the depth of partial melting, and that the separation distribution for hot spot <span class="hlt">volcanoes</span> near spreading centers provides a measure of the depth of mantle convection cells. It is further proposed that the lateral dimensions of mantle convection cells are also represented by the hot-spot separations (rather than by ridge-trench distances) and that a break in the distribution of hot spot separations at 3000 km is evidence for both whole mantle convection and a deep thermal plume origin of hot spots.</p> <div class="credits"> <p class="dwt_author">Lingenfelter, R. E.; Schubert, G.</p> <p class="dwt_publisher"></p> <p class="publishDate">1974-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">325</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=PIA03493&hterms=Leader+manager&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DLeader%2Bmanager"> <span id="translatedtitle">Chiliques <span class="hlt">volcano</span>, Chile</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary"><p/> A January 6, 2002 ASTER nighttime thermal infrared image of Chiliques <span class="hlt">volcano</span> 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 <span class="hlt">volcano</span> 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.<p/>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.<p/>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.<p/>These images were acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.<p/>ASTER is one of five Earth-observing instruments launched December 18,1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Bjorn Eng of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The Terra mission is part of NASA's Earth Science Enterprise, along-term research and technology program designed to examine Earth's land, oceans, atmosphere, ice and life as a total integrated system.<p/>The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active <span class="hlt">volcanoes</span>; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.<p/>Size: 7.5 x 7.5 km (4.5 x 4.5 miles) <span class="hlt">Location</span>: 23.6 deg. South lat., 67.6 deg. West long. Orientation: North at top Image Data: ASTER bands 1,2, and 3, and thermal band 12 Original Data Resolution: 15 m and 90 m Date Acquired: January 6, 2002 and November 19, 2000</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">326</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pbslearningmedia.org/resource/ean08.sci.ess.earthsys.infravol/"> <span id="translatedtitle"><span class="hlt">Volcanoes</span> in the Infrared</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">In this video adapted from KUAC-TV and the Geophysical Institute at the University of Alaska, Fairbanks, satellite imagery and infrared cameras are used to study and predict eruptions of <span class="hlt">volcanoes</span> in the Aleutian Islands, Alaska.</p> <div class="credits"> <p class="dwt_author">Foundation, Wgbh E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-02-27</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">327</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://gallery.usgs.gov/photos/mQHs38Vjj1_83"> <span id="translatedtitle">Vent of Sand <span class="hlt">Volcano</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://gallery.usgs.gov/">USGS Multimedia Gallery</a></p> <p class="result-summary">Vent of sand <span class="hlt">volcano</span> produced by liquefaction is about 4 ft across in strawberry field near Watsonville. Strip spanning vent is conduit for drip irrigation system. Furrow spacing is about 1.2 m (4 ft) on center....</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-26</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">328</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6728427"> <span id="translatedtitle">Fuel-cell-propelled <span class="hlt">submarine</span>-tanker-system study</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">This report provides a systems analysis of a commercial Arctic Ocean <span class="hlt">submarine</span> tanker system to carry fossil energy to markets. The <span class="hlt">submarine</span> is to be propelled by a modular Phosphoric Acid Fuel Cell system. The power level is 20 Megawatts. The DOE developed electric utility type fuel cell will be fueled with methanol. Oxidant will be provided from a liquid oxygen tank carried onboard. The twin screw <span class="hlt">submarine</span> tanker design is sized at 165,000 deadweight tons and the study includes costs and an economic analysis of the transport system of 6 ships. The route will be under the polar icecap from a loading terminal <span class="hlt">located</span> off Prudhoe Bay, Alaska to a transshipment facility postulated to be in a Norwegian fjord. The system throughput of the gas-fed methanol cargo will be 450,000 barrels per day. The total delivered cost of the methanol including well head purchase price of natural gas, methanol production, and shipping would be $25/bbl from Alaska to the US East Coast. Of this, the shipping cost is $6.80/bbl. All costs in 1981 dollars.</p> <div class="credits"> <p class="dwt_author">Court, K.E.; Kumm, W.H.; O'Callaghan, J.E.</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">329</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70015804"> <span id="translatedtitle">Geology of Medicine Lake <span class="hlt">Volcano</span>, Northern California Cascade Range</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Medicine Lake <span class="hlt">volcano</span> (MLV) is <span class="hlt">located</span> in an E-W extensional environment on the Modoc Plateau just east of the main arc of the Cascades. It consists mainly of mafic lavas, although drillhole data indicate that a larger volume of rhyolite is present than is indicated by surface mapping. The most recent eruption was rhyolitic and occurred about 900 years ago. At least seventeen eruptions have occurred since 12,000 years ago, or between 1 and 2 eruptions per century on average, although activity appears to be strongly episodic. The calculated eruptive rate is about 0.6 km3 per thousand years during the entire history of the <span class="hlt">volcano</span>. Drillhole data indicate that the plateau surface underlying the <span class="hlt">volcano</span> has been downwarped by 0.5 km under the center of MLV. The <span class="hlt">volcano</span> may be even larger than the estimated 600 km3, already the largest <span class="hlt">volcano</span> by volume in the Cascades.</p> <div class="credits"> <p class="dwt_author">Donnelly-Nolan, Julie</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">330</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dx.doi.org/10.1130/G19745.1"> <span id="translatedtitle">Ups and downs on spreading flanks of ocean-island <span class="hlt">volcanoes</span>: Evidence from Mauna Loa and Ki??lauea</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary"><span class="hlt">Submarine</span>-flank deposits of Hawaiian <span class="hlt">volcanoes</span> are widely recognized to have formed largely by gravitationally driven <span class="hlt">volcano</span> spreading and associated landsliding. Observations from submersibles show that prominent benches at middepths on flanks of Mauna Loa and Kilauea consist of volcaniclastic debris derived by landsliding from nearby shallow <span class="hlt">submarine</span> and subaerial flanks of the same edifice. Massive slide breccias from the mature subaerial tholeiitic shield of Mauna Loa underlie the frontal scarp of its South Kona bench. In contrast, coarse volcaniclastic sediments derived largely from <span class="hlt">submarine</span>-erupted preshield alkalic and transitional basalts of ancestral Kilauea underlie its Hilina bench. Both midslope benches record the same general processes of slope failure, followed by modest compression during continued <span class="hlt">volcano</span> spreading, even though they record development during different stages of edifice growth. The dive results suggest that volcaniclastic rocks at the north end of the Kona bench, interpreted by others as distal sediments from older <span class="hlt">volcanoes</span> that were offscraped, uplifted, and accreted to the island by far-traveled thrusts, alternatively are a largely coherent stratigraphic assemblage deposited in a basin behind the South Kona bench.</p> <div class="credits"> <p class="dwt_author">Lipman, P. W.; Eakins, B. W.; Yokose, H.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">331</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013EGUGA..15.7099C"> <span id="translatedtitle">Middle Pleistocene activity of the Hekla <span class="hlt">volcano</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Hekla <span class="hlt">volcano</span> is one of the most active <span class="hlt">volcanoes</span> in SE Iceland. Hekla is a ridge-shape stratovolcano, <span class="hlt">located</span> near the apex Icelandicelandic hot spot. It is <span class="hlt">located</span> on the SVZ, initiated with the last rift jump, c.3 Ma and the polarity of the basement lavas yields an age younger than 700 ka. Even if Holocene and late glacial eruptions are well constrained, little is known about the effective age of this <span class="hlt">volcano</span>. Hekla old lavas are mostly hyaloclastites and are difficult to date, while dykes are deeply weathered by late hydrothermal activity. Field data in the Rangavellir (ou mettre Ytri-Rangá valley) provide evidence for eruptions around the last Interglacial within a large coastal sedimentary prism, the Rangá Formation (130-80 ka) that is buried by the Búdi terminal moraines and Hekla Holocene lava flows. Emplaced after a highly erosive glaciation, this Rangá Formation contains a reworked trachytic tephra in form of pumice pellets that display a vesiculation similar to Hekla pumices. element'sd trace this tephra ts composition of these tephra is very similar to the Holocene pumice from Hekla <span class="hlt">volcano</span> and confirm that they are coming from an eruption produced by this <span class="hlt">volcano</span>. 40Ar-39Ar dating of these pumices yielded c.410ka. This age is very similar to those of other acidic <span class="hlt">volcanoes</span> around the Hofsjökull and the Vatnajökull (Kerlingarfjöll, Torfajökull, Laufafell, Nyðry Hagánga, Snæfell, Kverkfjöll) and also from the Snæfelness peninsula. This confirms that very large glaciations such as MIS 12 and 10 are followed by intense felsic volcanic activity at the onset of the deglaciations</p> <div class="credits"> <p class="dwt_author">Chazot, Gilles; Guillou, Hervé; Schneider, Jean-luc; Van Vliet-Lanoe, Brigitte</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">332</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.dggs.dnr.state.ak.us/pubs/id/14772"> <span id="translatedtitle">Preliminary <span class="hlt">volcano</span>-hazard assessment for Akutan <span class="hlt">Volcano</span> east-central Aleutian Islands, Alaska</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Akutan <span class="hlt">Volcano</span> is a 1100-meter-high stratovolcano on Akutan Island in the east-central Aleutian Islands of southwestern Alaska. The <span class="hlt">volcano</span> is <span class="hlt">located</span> about 1238 kilometers southwest of Anchorage and about 56 kilometers east of Dutch Harbor/Unalaska. Eruptive activity has occurred at least 27 times since historical observations were recorded beginning in the late 1700?s. Recent eruptions produced only small amounts of fine volcanic ash that fell primarily on the upper flanks of the <span class="hlt">volcano</span>. Small amounts of ash fell on the Akutan Harbor area during eruptions in 1911, 1948, 1987, and 1989. Plumes of volcanic ash are the primary hazard associated with eruptions of Akutan <span class="hlt">Volcano</span> and are a major hazard to all aircraft using the airfield at Dutch Harbor or approaching Akutan Island. Eruptions similar to historical Akutan eruptions should be anticipated in the future. Although unlikely, eruptions larger than those of historical time could generate significant amounts of volcanic ash, fallout, pyroclastic flows, and lahars that would be hazardous to life and property on all sectors of the <span class="hlt">volcano</span> and other parts of the island, but especially in the major valleys that head on the <span class="hlt">volcano</span> flanks. During a large eruption an ash cloud could be produced that may be hazardous to aircraft using the airfield at Cold Bay and the airspace downwind from the <span class="hlt">volcano</span>. In the event of a large eruption, volcanic ash fallout could be relatively thick over parts of Akutan Island and volcanic bombs could strike areas more than 10 kilometers from the <span class="hlt">volcano</span>.</p> <div class="credits"> <p class="dwt_author">Waythomas, Christopher F.; Power, John A.; Richter, Donlad H.; McGimsey, Robert G.</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">333</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/11066903"> <span id="translatedtitle">Assessment of tsunami hazard to the U.S. East Coast using relationships between <span class="hlt">submarine</span> landslides and earthquakes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Submarine</span> landslides along the continental slope of the U.S. Atlantic margin are potential sources for tsunamis along the U.S. East coast. The magnitude of potential tsunamis depends on the volume and <span class="hlt">location</span> of the landslides, and tsunami frequency depends on their recurrence interval. However, the size and recurrence interval of <span class="hlt">submarine</span> landslides along the U.S. Atlantic margin is poorly known.</p> <div class="credits"> <p class="dwt_author">Uri S. ten Brink; Homa J. Lee; Eric L. Geist; David Twichell</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">334</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dx.doi.org/10.1016/j.margeo.2008.09.009"> <span id="translatedtitle">Timing of occurrence of large <span class="hlt">submarine</span> landslides on the Atlantic Ocean margin</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary"><span class="hlt">Submarine</span> landslides are distributed unevenly both in space and time. Spatially, they occur most commonly in fjords, active river deltas, <span class="hlt">submarine</span> canyon-fan systems, the open continental slope and on the flanks of oceanic volcanic islands. Temporally, they are influenced by the size, <span class="hlt">location</span>, and sedimentology of migrating depocenters, changes in seafloor pressures and temperatures, variations in seismicity and volcanic activity, and changes in groundwater flow conditions. The dominant factor influencing the timing of <span class="hlt">submarine</span> landslide occurrence is glaciation. A review of known ages of <span class="hlt">submarine</span> landslides along the margins of the Atlantic Ocean, augmented by a few ages from other <span class="hlt">submarine</span> <span class="hlt">locations</span> shows a relatively even distribution of large landslides with time from the last glacial maximum until about five thousand years after the end of glaciation. During the past 5000??yr, the frequency of occurrence is less by a factor of 1.7 to 3.5 than during or shortly after the last glacial/deglaciation period. Such an association likely exists because of the formation of thick deposits of sediment on the upper continental slope during glacial periods and increased seismicity caused by isostatic readjustment during and following deglaciation. Hydrate dissociation may play a role, as suggested previously in the literature, but the connection is unclear.</p> <div class="credits"> <p class="dwt_author">Lee, H. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">335</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.usgs.gov/of/2002/0342/@noteCOMPANION+FILES#texthttp://pubs.usgs.gov/of/2002/0342/avocatalog2000_2001.tar.z.Z@noteADDITIONAL+REPORT+PIECE#texthttp://pubs.usgs.gov/of/2002/0342/catalogavo.txt@noteAPPENDIX#texthttp://pubs.usgs.gov/of/2002/0342/pdf/appendixf.pdf@noteDOCUMENT#texthttp://pubs.usgs.gov/of/2002/0342/pdf/of02-342.pdf"> <span id="translatedtitle">Catalog of earthquake hypocenters at Alaskan <span class="hlt">volcanoes</span>: January 1, 2000 through December 31, 2001</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">The Alaska <span class="hlt">Volcano</span> Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at potentially active <span class="hlt">volcanoes</span> in Alaska since 1988 (Power and others, 1993; Jolly and others, 1996; Jolly and others, 2001). The primary objectives of this program are the seismic surveillance of active, potentially hazardous, Alaskan <span class="hlt">volcanoes</span> and the investigation of seismic processes associated with active volcanism. This catalog reflects the status and evolution of the seismic monitoring program, and presents the basic seismic data for the time period January 1, 2000, through December 31, 2001. For an interpretation of these data and previously recorded data, the reader should refer to several recent articles on <span class="hlt">volcano</span> related seismicity on Alaskan <span class="hlt">volcanoes</span> in Appendix G. The AVO seismic network was used to monitor twenty-three <span class="hlt">volcanoes</span> in real time in 2000-2001. These include Mount Wrangell, Mount Spurr, Redoubt <span class="hlt">Volcano</span>, Iliamna <span class="hlt">Volcano</span>, Augustine <span class="hlt">Volcano</span>, Katmai Volcanic Group (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident <span class="hlt">Volcano</span>, Mount Mageik, Mount Martin), Aniakchak Crater, Pavlof <span class="hlt">Volcano</span>, Mount Dutton, Isanotski Peaks, Shishaldin <span class="hlt">Volcano</span>, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin <span class="hlt">Volcano</span>, Great Sitkin <span class="hlt">Volcano</span>, and Kanaga <span class="hlt">Volcano</span> (Figure 1). AVO <span class="hlt">located</span> 1551 and 1428 earthquakes in 2000 and 2001, respectively, on and around these <span class="hlt">volcanoes</span>. Highlights of the catalog period (Table 1) include: volcanogenic seismic swarms at Shishaldin <span class="hlt">Volcano</span> between January and February 2000 and between May and June 2000; an eruption at Mount Cleveland between February and May 2001; episodes of possible tremor at Makushin <span class="hlt">Volcano</span> starting March 2001 and continuing through 2001, and two earthquake swarms at Great Sitkin <span class="hlt">Volcano</span> in 2001. This catalog includes: (1) earthquake origin times, hypocenters, and magnitudes with summary statistics describing the earthquake <span class="hlt">location</span> quality; (2) a description of instruments deployed in the field and their <span class="hlt">locations</span>; (3) a description of earthquake detection, recording, analysis, and data archival systems; (4) station parameters and velocity models used for earthquake <span class="hlt">locations</span>; (5) a summary of daily station usage throughout the catalog period; and (6) all HYPOELLIPSE files used to determine the earthquake <span class="hlt">locations</span> presented in this report.</p> <div class="credits"> <p class="dwt_author">Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Estes, Steve; Moran, Seth C.; Paskievitch, John; McNutt, Stephen R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">336</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/2511509"> <span id="translatedtitle">A <span class="hlt">submarine</span> shipboard smoking cessation program.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The discouragement of tobacco abuse in the military requires effective smoking cessation assistance for all active duty and dependent personnel. Specifically tailoring this assistance to the unique features of the various military communities will help to make it more effective. The program presented herein was designed for use in the <span class="hlt">submarine</span> fleet. It combines basic proven workplace smoking cessation techniques with lessons learned from experience in <span class="hlt">submarines</span>. It is believed that other military populations can benefit from similar efforts. This paper is an abridged version of the author's <span class="hlt">Submarine</span> Medical Officer qualification thesis. PMID:2511509</p> <div class="credits"> <p class="dwt_author">Scali, W K</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">337</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010AGUFM.T13B2186D"> <span id="translatedtitle">Volcanic Explosions, Seismicity, and Debris from the West and North Mata <span class="hlt">Volcano</span> Complex, NE Lau Basin</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The discovery of the explosively erupting deep-ocean West Mata <span class="hlt">volcano</span> in the northeast Lau Basin offers an unprecedented opportunity for in situ and near-field studies of the hydroacoustic wavefield produced by a <span class="hlt">submarine</span> arc <span class="hlt">volcano</span>, as well as the relationship between gas-driven explosions and the formation of volcanic-hydrothermal plumes. From December 2009 to April 2010, we re-initiated acoustic monitoring of the West Mata system by deploying four hydrophone moorings in a diamond-shaped geometry encompassing the summit and a set of nearby volcanic edifices known as the North Matas. Recent water column surveys over the North Matas found intense volcanic plumes suggesting that one or more of these <span class="hlt">volcanoes</span> may be in an active eruption phase similar to West Mata. Each mooring contained a single sound-channel moored hydrophone (~1000 m depth) with a sample-rate of 1 kHz. The southern mooring in the array also included two optical backscatter and temperature sensors (MAPRs) attached to the mooring line (at 1800 m (data lost due to a battery failure) and 2250 m (~300 mab) depth) to detect plumes of volcanic debris that detach from the flank of West Mata. The acoustic record shows that West Mata <span class="hlt">volcano</span> was continually erupting during the 5-month period of the experiment, producing broadband explosions every few seconds and long episodes of both mono- and poly-chromatic volcanic tremor. The MAPR record shows at least four major and several minor events, lasting from days to >week, that may correspond to debris flows. In most cases these episodes begin with a turbidity spike that slowly decreases while also fluctuating between elevated and ambient levels with the semidiurnal tides, as indicated by the temperature record. This linked temperature-turbidity fluctuation requires the events to be thin (<~100 m?) lenses that vertically oscillate around the MAPR depth while dissipating. High turbidity values (0.15-5 NTU) in some events imply these debris flows regularly move substantial quantities of material downslope. Source <span class="hlt">locations</span> derived from the first 700 explosions recorded (~12 hrs) are near the northwest summit of West Mata, consistent with the <span class="hlt">locations</span> of previously mapped eruption vents. Earthquake (T-phase) <span class="hlt">locations</span> derived to date show dozens of events focused at the northernmost North Mata <span class="hlt">volcano</span> as well as hundreds of earthquakes from throughout the region. A contemporaneous Lau Basin hydrophone experiment showed that West Mata explosions and tremor can be detected ~600 km to the south, illustrating that West Mata is a significant, continuous source of seismo-acoustic energy in the region and offers a rare chance to ground-truth the sounds of deep-ocean eruptions since they were originally recognized on far-field military hydrophones during the 1950s.</p> <div class="credits"> <p class="dwt_author">Dziak, R. P.; Bohnenstiehl, D. R.; Baker, E. T.; Matsumoto, H.; Haxel, J.; Walker, S.; Fowler, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">338</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005AGUFM.V13F..01D"> <span id="translatedtitle">Comparison of the <span class="hlt">Submarine</span> 1888 Ritter and the Subaerial 1980 Mount St Helens Debris Avalanche Deposits</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The lateral collapse of Ritter Island <span class="hlt">volcano</span>, Papua New Guinea, on March 13th 1888 was nearly twice the volume of the lateral collapse of Mount St Helens on May 18th 1980 (4 to 5 km3 compared to 2.8 km3) and the resulting landslide traveled about twice the distance (~75 km for Ritter and ~30 km for MSH). Both landslides descended valleys producing topographically - controlled deposit distributions. Sonar mapping and deep tow camera imaging indicate that the Ritter Island deposit is exceptionally well exposed for a <span class="hlt">submarine</span> debris avalanche deposit, most likely due to its very young age. Comparing the Ritter and MSH deposits in terms of their geometry, areas of associated substrate erosion, and the development of different morphological facies, provides insights into the kinematic and mechanical similarities and differences between subaerial and <span class="hlt">submarine</span> debris avalanches resulting from <span class="hlt">volcano</span> lateral collapses. Although both deposits have block - rich and matrix - rich facies, extensive substrate erosion in the distal part of the Ritter Island landslide resulted in the incorporation of water - rich sediment and transformation of the debris avalanche into a debris flow rich in sediment intraclasts.</p> <div class="credits"> <p class="dwt_author">Day, S.; Silver, E.; Ward, S.; Gary, H.; Amelia, L.; Llanes-Estrada, P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">339</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70020337"> <span id="translatedtitle">Boron-rich mud <span class="hlt">volcanoes</span> of the Black Sea region: modern analogues to ancient sea-floor tourmalinites associated with Sullivan-type Pb-Zn deposits?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Large <span class="hlt">submarine</span> mud <span class="hlt">volcanoes</span> in the abyssal part of the Black Sea south of the Crimean Peninsula are similar in many respects to synsedimentary mud <span class="hlt">volcanoes</span> in the Mesoproterozoic Belt-Purcell basin. One of the Belt-Purcell mud <span class="hlt">volcanoes</span> directly underlies the giant Sullivan Pb-Zn-Ag deposit in southeastern British Columbia. Footwall rocks to the Sullivan deposit comprise variably tourmalinized siltstone, conglomerate, and related fragmental rock; local thin pyrrhotite-rich and spessartine-quartz beds are interpreted as Fe and Fe-Mn exhalites, respectively. Analogous Fe- and Mn-rich sediments occur near the abyssal Black Sea mud <span class="hlt">volcanoes</span>. Massive pyrite crusts and associated carbonate chimneys discovered in relatively shallow waters (~200 m depth) west of the Crimean Peninsula indicate an active sea-floor-hydrothermal system. Subaerial mud <span class="hlt">volcanoes</span> on the Kerch and Taman Peninsulas (~100 km north of the abyssal mud <span class="hlt">volcanoes</span>) contain saline thermal waters that locally have very high B contents (to 915 mg/L). These data suggest that tourmalinites might be forming in or near <span class="hlt">submarine</span> Black Sea mud <span class="hlt">volcanoes</span>, where potential may also exist for Sullivan-type Pb-Zn mineralization.</p> <div class="credits"> <p class="dwt_author">Slack, J. F.; Turner, R. J. W.; Ware, P. L. G.</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">340</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.usgs.gov/of/2003/0267/@noteCOMPANION+FILES#texthttp://pubs.usgs.gov/of/2003/0267/2002AVOEarthquakeCatalog.tar.Z@noteAPPENDIX#texthttp://pubs.usgs.gov/of/2003/0267/pdf/appendixf.pdf@noteDOCUMENT#texthttp://pubs.usgs.gov/of/2003/0267/pdf/of03-267.pdf"> <span id="translatedtitle">Catalog of earthquake hypocenters at Alaskan <span class="hlt">volcanoes</span>: January 1 through December 31, 2002</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">The Alaska <span class="hlt">Volcano</span> Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at historically active <span class="hlt">volcanoes</span> in Alaska since 1988 (Power and others, 1993; Jolly and others, 1996; Jolly and others, 2001; Dixon and others, 2002). The primary objectives of this program are the seismic monitoring of active, potentially hazardous, Alaskan <span class="hlt">volcanoes</span> and the investigation of seismic processes associated with active volcanism. This catalog presents the basic seismic data and changes in the seismic monitoring program for the period January 1, 2002 through December 31, 2002. Appendix G contains a list of publications pertaining to seismicity of Alaskan <span class="hlt">volcanoes</span> based on these and previously recorded data. The AVO seismic network was used to monitor twenty-four <span class="hlt">volcanoes</span> in real time in 2002. These include Mount Wrangell, Mount Spurr, Redoubt <span class="hlt">Volcano</span>, Iliamna <span class="hlt">Volcano</span>, Augustine <span class="hlt">Volcano</span>, Katmai Volcanic Group (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident <span class="hlt">Volcano</span>, Mount Mageik, Mount Martin), Aniakchak Crater, Mount Veniaminof, Pavlof <span class="hlt">Volcano</span>, Mount Dutton, Isanotski Peaks, Shishaldin <span class="hlt">Volcano</span>, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin <span class="hlt">Volcano</span>, Great Sitkin <span class="hlt">Volcano</span>, and Kanaga <span class="hlt">Volcano</span> (Figure 1). Monitoring highlights in 2002 include an earthquake swarm at Great Sitkin <span class="hlt">Volcano</span> in May-June; an earthquake swarm near Snowy Mountain in July-September; low frequency (1-3 Hz) tremor and long-period events at Mount Veniaminof in September-October and in December; and continuing volcanogenic seismic swarms at Shishaldin <span class="hlt">Volcano</span> throughout the year. Instrumentation and data acquisition highlights in 2002 were the installation of a subnetwork on Okmok <span class="hlt">Volcano</span>, the establishment of telemetry for the Mount Veniaminof subnetwork, and the change in the data acquisition system to an EARTHWORM detection system. AVO <span class="hlt">located</span> 7430 earthquakes during 2002 in the vicinity of the monitored <span class="hlt">volcanoes</span>. This catalog includes: (1) a description of instruments deployed in the field and their <span class="hlt">locations</span>; (2) a description of earthquake detection, recording, analysis, and data archival systems; (3) a description of velocity models used for earthquake <span class="hlt">locations</span>; (4) a summary of earthquakes <span class="hlt">located</span> in 2002; and (5) an accompanying UNIX tar-file with a summary of earthquake origin times, hypocenters, magnitudes, and <span class="hlt">location</span> quality statistics; daily station usage statistics; and all HYPOELLIPSE files used to determine the earthquake <span class="hlt">locations</span> in 2002.</p> <div class="credits"> <p class="dwt_author">Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Moran, Seth C.; Sánchez, John; Estes, Steve; McNutt, Stephen R.; Paskievitch, John</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div 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class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">341</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012BVol...74.1937M"> <span id="translatedtitle">Explosion craters associated with shallow <span class="hlt">submarine</span> gas venting off Panarea island, Italy</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Explosions of hot water, steam, and gas are common periodic events of subaerial geothermal systems. These highly destructive events may cause loss of life and substantial damage to infrastructure, especially in densely populated areas and where geothermal systems are actively exploited for energy. We report on the occurrence of a large number of explosion craters associated with the offshore venting of gas and thermal waters at the volcanic island of Panarea, Italy, demonstrating that violent explosions similar to those observed on land also are common in the shallow <span class="hlt">submarine</span> environment. With diameters ranging from 5 to over 100 m, the observed circular seafloor depressions record a history of major gas explosions caused by frequent perturbation of the <span class="hlt">submarine</span> geothermal system over the past 10,000 years. Estimates of the total gas flux indicate that the Panarea geothermal system released over 70 Mt of CO2 over this period of time, suggesting that CO2 venting at submerged arc <span class="hlt">volcanoes</span> contributes significantly to the global atmospheric budget of this greenhouse gas. The findings at Panarea highlight that shallow <span class="hlt">submarine</span> gas explosions represent a previously unrecognized volcanic hazard around populated volcanic islands that needs to be taken into account in the development of risk management strategies.</p> <div class="credits"> <p class="dwt_author">Monecke, Thomas; Petersen, Sven; Hannington, Mark D.; Anzidei, Marco; Esposito, Alessandra; Giordano, Guido; Garbe-Schönberg, Dieter; Augustin, Nico; Melchert, Bernd; Hocking, Mike</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">342</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=AD771346"> <span id="translatedtitle">Novel Approach to Improved <span class="hlt">Submarine</span> Escape Performance.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">Conventional compressed air-based <span class="hlt">submarine</span> excape techniques have been developed to the extent where only new approaches will yield a significant increase in performance. The novel approach suggested here is to substitute for nitrogen in the breathing mi...</p> <div class="credits"> <p class="dwt_author">D. J. Gait K. W. Miller</p> <p class="dwt_publisher"></p> <p class="publishDate">1973-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">343</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE97749517"> <span id="translatedtitle">Seismic reflections associated with <span class="hlt">submarine</span> gas hydrates.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">Gas hydrates are often suggested as a future energy resource. This doctoral thesis improves the understanding of the concentration and distribution of natural <span class="hlt">submarine</span> gas hydrates. The presence of these hydrates are commonly inferred from strong bottom ...</p> <div class="credits"> <p class="dwt_author">K. Andreassen</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">344</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=ADA534793"> <span id="translatedtitle">Obsolescence Management for Virginia-Class <span class="hlt">Submarines</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">This case study describes how the Navy resolves technology obsolescence issues that directly affect the operational capability, safety, and reliability of almost every major electronics system on Virginia-class <span class="hlt">submarines</span>. To date, the Navy has solved app...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">345</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/825888"> <span id="translatedtitle">CHALLENGES POSED BY RETIRED RUSSIAN NUCLEAR <span class="hlt">SUBMARINES</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The purpose of this paper is to provide an overview of the challenges posed by retired Russian nuclear <span class="hlt">submarines</span>, review current U.S. and International efforts and provide an assessment of the success of these efforts.</p> <div class="credits"> <p class="dwt_author">Rudolph, Dieter; Kroken, Ingjerd; Latyshev, Eduard; Griffith, Andrew</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-02-27</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">346</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://vulcan.wr.usgs.gov/Vhp/C1073/"> <span id="translatedtitle">Living With <span class="hlt">Volcanoes</span>: The USGS <span class="hlt">Volcano</span> Hazards Program</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This report summarizes the <span class="hlt">Volcano</span> Hazards Program of the United States Geological Survey (USGS). Topics include its goals and activities, some key accomplishments, and a plan for future operations. There are also discussions of active and potentially active <span class="hlt">volcanoes</span> in the U.S., the role of the USGS <span class="hlt">volcano</span> observatories, prediction of eruptions, and potential danger to aircraft from volcanic plumes.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">347</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=volcanoes&pg=4&id=EJ232816"> <span id="translatedtitle"><span class="hlt">Volcanoes</span>: Coming Up from Under.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">Provides specific information about the eruption of Mt. St. Helens in March 1980. Also discusses how <span class="hlt">volcanoes</span> are formed and how they are monitored. Words associated with <span class="hlt">volcanoes</span> are listed and defined. (CS)</p> <div class="credits"> <p class="dwt_author">Science and Children, 1980</p> <p class="dwt_publisher"></p> <p class="publishDate">1980-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">348</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://learningcenter.nsta.org/product_detail.aspx?id=10.2505/4/ss08_031_07_12"> <span id="translatedtitle">Tried and True: <span class="hlt">Volcano</span> r�sum�s</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">Tired of building a paper m�ch� <span class="hlt">volcano</span> to teach about plate tectonics? Do you want to connect science and writing? Then the <span class="hlt">volcano</span> r�sum� project is perfect for you. This one-week, problem-based learning (PBL) project requires students to research a specific <span class="hlt">volcano</span> and then create a r�sum� for it that describes its <span class="hlt">location</span>, physical characteristics, eruption history, and additional information of interest. Students are also required to include references for the information included on their r�sum�s.</p> <div class="credits"> <p class="dwt_author">Corlett, Cindy; Rutherford, Sandra</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">349</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dx.doi.org/10.1016/j.jvolgeores.2005.07.037"> <span id="translatedtitle">Growth history of Kilauea inferred from volatile concentrations in <span class="hlt">submarine</span>-collected basalts</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Major-element and volatile (H2O, CO2, S) compositions of glasses from the <span class="hlt">submarine</span> flanks of Kilauea <span class="hlt">Volcano</span> record its growth from pre-shield into tholeiite shield-stage. Pillow lavas of mildly alkalic basalt at 2600-1900 mbsl on the upper slope of the south flank are an intermediate link between deeper alkalic volcaniclastics and the modern tholeiite shield. Lava clast glasses from the west flank of Papau Seamount are subaerial Mauna Loa-like tholeiite and mark the contact between the two <span class="hlt">volcanoes</span>. H2O and CO2 in sandstone and breccia glasses from the Hilina bench, and in alkalic to tholeiitic pillow glasses above and to the east, were measured by FTIR. Volatile saturation pressures equal sampling depths (10 MPa = 1000 m water) for south flank and Puna Ridge pillow lavas, suggesting recovery near eruption depths and/or vapor re-equilibration during down-slope flow. South flank glasses are divisible into low-pressure (CO20.5 wt.%, S 1000-1700 ppm), and high-pressure groups (CO2 >40 ppm, S >???1000 ppm), corresponding to eruption ???sea level, at moderate water depths (300-1000 m) or shallower but in disequilibrium, and in deep water (> 1000 m). Saturation pressures range widely in early alkalic to strongly alkalic breccia clast and sandstone glasses, establishing that early Kilauea's vents spanned much of Mauna Loa's <span class="hlt">submarine</span> flank, with some vents exceeding sea level. Later south flank alkalic pillow lavas expose a sizeable <span class="hlt">submarine</span> edifice that grew concurrent with nearby subaerial alkalic eruptions. The onset of the tholeiitic shield stage is marked by extension of eruptions eastward and into deeper water (to 5500 m) during growth of the Puna Ridge. Subaerial and shallow water eruptions from earliest Kilauea show that it is underlain shallowly by Mauna Loa, implying that Mauna Loa is larger, and Kilauea smaller, than previously recognized.</p> <div class="credits"> <p class="dwt_author">Coombs, M. L.; Sisson, T. W.; Lipman, P. W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">350</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFMOS53B1695I"> <span id="translatedtitle">Hydraulic and Morphodynamic Characteristics of <span class="hlt">Submarine</span> Channel Confluences</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Submarine</span> channel systems are receiving increased attention recently for their potential in transporting and depositing hydrocarbons via turbidity currents into the deep ocean. In order to better predict the <span class="hlt">locations</span> of hydrocarbon reserves, a more complete understanding of the hydraulic behavior of flows within the channels is necessary. Past field observations have shown that <span class="hlt">submarine</span> channels have straight and meandering reaches, along with junctions in channel systems; flows in the <span class="hlt">submarine</span> environment (i.e. density currents) may propagate as a single pulse or as a sustained flow over a prolonged period. This work aims to further the understanding of <span class="hlt">submarine</span> channel systems by focusing on the hydraulic behavior of <span class="hlt">submarine</span> channel confluences due to both sudden release (i.e. pulse events) and sustained flows. The associated morphodynamic consequences at and near the confluence are also assessed as they relate to the observed hydraulic conditions. Observational goals include comparisons to heavily studied characteristics of subaerial river channel confluences. These include flow separation zones, helical flow cells, existence of vertical shear layers, avalanche faces upstream of the junction, and deep central scours in the junction. For this investigation, a physical model was built to simulate a 45 degree <span class="hlt">submarine</span> channel junction with an erodible bed in which two fully conservative density currents are released in each upstream reach and allowed to collide before creating a single combined current in the downstream reach. The pulse events focused on the head of the density currents and were simulated using a lock-exchange mechanism in which a fixed volume of salt water was locked in each upstream reach of the flume before being suddenly released into the ambient water downstream. HD images were used to obtain 1D velocity both up- and down-stream of the junction, and bathymetry measurements were obtained using an ultrasonic probe after each experiment. The sustained (i.e. steady) events focus on the body of the current and were simulated by continuously releasing salt water into the flume initially filled with ambient water. In this case, 2D velocity measurements were obtained around the junction at five elevations, and bed evolution is tracked qualitatively after each test. It has been observed that: 1) a clear shear layer forms between contributing flows; 2) there is evidence of flow separation near the bed downstream of the junction; 3) the current accelerates as it reforms after the collision in the junction; 4) the <span class="hlt">location</span> and orientation of the central scour differs from river junctions in the sustained case; 5) the sudden release case shows very little scour in the junction zone. This data is used to develop and validate a numerical simulation of both types of density current releases in which further variations on initial conditions can be assessed for their impact on the velocity field and sediment transport in <span class="hlt">submarine</span> channel junctions.</p> <div class="credits"> <p class="dwt_author">Ismail, H.; Viparelli, E.; Ezz, H.; Imran, J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">351</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/16844646"> <span id="translatedtitle"><span class="hlt">Submarine</span> landslides: processes, triggers and hazard prediction.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Huge landslides, mobilizing hundreds to thousands of km(3) of sediment and rock are ubiquitous in <span class="hlt">submarine</span> settings ranging from the steepest volcanic island slopes to the gentlest muddy slopes of <span class="hlt">submarine</span> deltas. Here, we summarize current knowledge of such landslides and the problems of assessing their hazard potential. The major hazards related to <span class="hlt">submarine</span> landslides include destruction of seabed infrastructure, collapse of coastal areas into the sea and landslide-generated tsunamis. Most <span class="hlt">submarine</span> slopes are inherently stable. Elevated pore pressures (leading to decreased frictional resistance to sliding) and specific weak layers within stratified sequences appear to be the key factors influencing landslide occurrence. Elevated pore pressures can result from normal depositional processes or from transient processes such as earthquake shaking; historical evidence suggests that the majority of large <span class="hlt">submarine</span> landslides are triggered by earthquakes. Because of their tsunamigenic potential, ocean-island flank collapses and rockslides in fjords have been identified as the most dangerous of all landslide related hazards. Published models of ocean-island landslides mainly examine 'worst-case scenarios' that have a low probability of occurrence. Areas prone to <span class="hlt">submarine</span> landsliding are relatively easy to identify, but we are still some way from being able to forecast individual events with precision. Monitoring of critical areas where landslides might be imminent and modelling landslide consequences so that appropriate mitigation strategies can be developed would appear to be areas where advances on current practice are possible. PMID:16844646</p> <div class="credits"> <p class="dwt_author">Masson, D G; Harbitz, C B; Wynn, R B; Pedersen, G; Løvholt, F</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-08-15</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">352</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013EGUGA..1512028H"> <span id="translatedtitle">Topographic analysis of <span class="hlt">submarine</span> cable failures offshore southwestern taiwan</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In 2006, there was large scale of the <span class="hlt">submarine</span> cable failures offshore southern Taiwan right after the Pingtung Earthquake. Apparently the December 26 Pingtung Earthquake triggered <span class="hlt">submarine</span> mass movements which generated turbidity currents in the <span class="hlt">submarine</span> canyons and damaged cables lying across the canyons. In addition, the Typhoon Morakot on August 8-9, 2009 and the Jiashian Earthquake on March 4, 2010 also caused many <span class="hlt">submarine</span> cable failures offshore southwestern Taiwan. The most of broken cable sites are along the axis of the Gaoping <span class="hlt">Submarine</span> Canyon (GPSC) and Fangliao <span class="hlt">Submarine</span> Canyon (FLSC), topography should be an important factor controlling transport processes of <span class="hlt">submarine</span> mass movement. The cable broken sites indicate that there were <span class="hlt">submarine</span> mass movement pass through. Therefore, the topographic factor of the cable broken sites can be the threshold to index <span class="hlt">submarine</span> mass movement. And as, <span class="hlt">submarine</span> cables are distributed widely offshore southwestern Taiwan, why only a total of 35 sites of <span class="hlt">submarine</span> cable failures occurred in 2006, 2009 and 2010? We use bathymetry data, CHIRP (compressed high-intensity radar pulse) sonar profile data and the time series of the cable breakage to investigate the characteristics of <span class="hlt">submarine</span> mass movement and to develop a model for the series of <span class="hlt">submarine</span> cable failure. Using the Geographic Information System (GIS) software, we analyze the bathymetric data collected before the 35 sites of <span class="hlt">submarine</span> cable failures offshore southwestern Taiwan. Applying the hydrology in GIS software, the flow movement could be derived from the factors of slope and aspect. We quantify the transport process of <span class="hlt">submarine</span> mass movement and combine with the time series of the cable breakage to discuss the effect between <span class="hlt">submarine</span> cable failures. Based on the CHIRP sonar data, we identified the distinct CHIRP echo character patterns after the <span class="hlt">submarine</span> cable failures and classify the distinct CHIRP echo characters. Using the threshold of topographic factor to expect where will be potential area of <span class="hlt">submarine</span> mass movement and evidence the result by CHIRP sonar profile data.</p> <div class="credits"> <p class="dwt_author">Hsia, Pei Cheng; Shine Liu, Char; Hsu, Ho Han</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">353</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=AD609647"> <span id="translatedtitle">The Development and Evaluation of Polystyrene Foam Container for MK 66 Type <span class="hlt">Submarine</span> Signals.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">An improved method for packaging the Mk 66, 67 and 68 <span class="hlt">Submarine</span> Smoke and Illumination Signals and the Mk 28 Marine <span class="hlt">Location</span> Marker has been developed and evaluated, as described in this report. The container is made of polystyrene foam, an economical and...</p> <div class="credits"> <p class="dwt_author">F. A. Niehaus</p> <p class="dwt_publisher"></p> <p class="publishDate">1964-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">354</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=ADA427127"> <span id="translatedtitle">Detailed Study of the Flowfield of a <span class="hlt">Submarine</span> Propeller During a Crashback Maneuver.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">An extensive study of crashback was performed in the U.S. Navy's William B. Morgan Large Cavitation Channel (LCC), <span class="hlt">located</span> in Memphis, TN. Propeller 4381 was attached to a standard axisymmetric <span class="hlt">submarine</span> hull model (DTMB Model 5495-3) which was then suspe...</p> <div class="credits"> <p class="dwt_author">D. H. Bridges</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">355</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012JHyd..464...27M"> <span id="translatedtitle">Methodological study of <span class="hlt">submarine</span> groundwater discharge from a karstic aquifer in the Western Mediterranean Sea</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We applied an approach for localising and quantify SGD from a coastal aquifer. Airborne infrared night imaging were very useful to localising near-shore springs. We compare methods of calculating terms of water balance with radium quarter results. <span class="hlt">Submarine</span> outflows on the continental shelf were also <span class="hlt">located</span> but not estimated yet.</p> <div class="credits"> <p class="dwt_author">Mejías, Miguel; Ballesteros, Bruno J.; Antón-Pacheco, Carmen; Domínguez, José A.; Garcia-Orellana, Jordi; Garcia-Solsona, Ester; Masqué, Pere</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">356</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AGUFM.V33B2632E"> <span id="translatedtitle">Investigating the Source Mechanism of Long Period <span class="hlt">Volcano</span>-Seismic Events Recorded in 2009 at Turrialba <span class="hlt">Volcano</span>, Costa Rica</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Long-period (LP) seismic events (with energy concentrated between frequencies of 0.5 to 5Hz) were recorded on Turrialba <span class="hlt">volcano</span>, Costa Rica during a field experiment from March to September 2009. This type of event has been recorded at many <span class="hlt">volcanoes</span> across the world and in some instances swarms of LP events have signalled the onset of a volcanic eruption. The most widely accepted models for the source mechanism of these events attribute them to resonance within a fluid-filled cavity within the <span class="hlt">volcano</span>, due to the similarity between waveforms of different LP events suggesting a non-destructive, repeatable source. Therefore inverting recorded LP events for the source mechanism can provide valuable information about the internal structure and dynamics of the <span class="hlt">volcano</span>. Turrialba <span class="hlt">volcano</span> is an ideal <span class="hlt">volcano</span> on which to carry out this experiment because of the relatively easy and safe access to the <span class="hlt">volcano</span> summit. This is important because it has been shown in previous studies that seismometers should be <span class="hlt">located</span> in a dense network across the summit of a <span class="hlt">volcano</span> (above the source), in order to gain as accurate a source inversion as possible. Activity at Turrialba <span class="hlt">volcano</span> has increased dramatically in recent years with high levels of seismic and fumerolic activity. In this study 16 broadband seismometers were deployed on the summit and flanks of the <span class="hlt">volcano</span>, including a 5 station array that was in operation for ~2 weeks. The data from the field experiment has been analysed and the LP events found. These were sorted into five families based on their correlations. The source <span class="hlt">locations</span> have been calculated using a variety of methods including first picks, array analysis and a gridsearch implemented while carrying out moment tensor inversion. The LP events are <span class="hlt">located</span> below the summit craters at shallow depth. These <span class="hlt">locations</span> were then used to carry out full waveform moment tensor inversion to constrain the source mechanism, using a full waveform method to calculate the Green's functions. From unconstrained inversion, the optimum source for LP events is a crack mechanism. Constrained inversion will be carried out to better constrain the orientation of the crack. This will lead to a much greater understanding of the magmatic and hydrothermal systems within Turrialba <span class="hlt">volcano</span> and better constraints on LP event source mechanism within <span class="hlt">volcanoes</span> in general.</p> <div class="credits"> <p class="dwt_author">Eyre, T. S.; Bean, C. J.; O'Brien, G. S.; Martini, F.; Mora, M. M.; Pacheco, J. F.; Soto, G. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">357</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.geo.mtu.edu/volcanoes/index.html"> <span id="translatedtitle">Michigan Technological University <span class="hlt">Volcanoes</span> Page</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This site offers links to current volcanic activity reports, volcanic hazards mitigation, information on Central American <span class="hlt">volcanoes</span>, remote sensing of <span class="hlt">volcanoes</span>, volcanologic research in online journals, and more. There are also links to a site with information on becoming a volcanologist, and a comics page of <span class="hlt">volcano</span> humor.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">358</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/41168513"> <span id="translatedtitle">Earthquake triggering of mud <span class="hlt">volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Mud <span class="hlt">volcanoes</span> sometimes erupt within days after nearby earthquakes. The number of such nearly coincident events is larger than would be expected by chance and the eruptions are thus assumed to be triggered by earthquakes. Here we compile observations of the response of mud <span class="hlt">volcanoes</span> and other geologic systems (earthquakes, <span class="hlt">volcanoes</span>, liquefaction, ground water, and geysers) to earthquakes. The compilation</p> <div class="credits"> <p class="dwt_author">Michael Manga; Maria Brumm; Maxwell L. Rudolph</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">359</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=MSFC-0203323&hterms=history+volcanoes&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dhistory%2Bvolcanoes"> <span id="translatedtitle">Erupting <span class="hlt">Volcano</span> Mount Etna</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Expedition Five crew members aboard the International Space Station (ISS) captured this overhead look at the smoke and ash regurgitated from the erupting <span class="hlt">volcano</span> 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 <span class="hlt">volcano</span>, one of the most active and most studied <span class="hlt">volcanoes</span> in the world, has been active for a half-million years and has erupted hundreds of times in recorded history.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">360</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.nationalgeographic.com/xpeditions/lessons/15/g35/earthquakes.html"> <span id="translatedtitle">Earthquakes and <span class="hlt">Volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This activity has students compare maps of plate tectonics with population density maps and to analyze what these maps imply about the relationship between population and seismic hazards. Students will read about and discuss the theory of plate tectonics, map the regions of the United States that are most susceptible to earthquakes and those that have <span class="hlt">volcanoes</span>, and list the states that lie on plate boundaries. In addition, they will look at a population density map to determine if people avoid living in areas at high risk for earthquakes and <span class="hlt">volcanoes</span>. Students will also research specific <span class="hlt">volcanoes</span> or earthquake zones and write pretend letters to residents of these areas describing the risks. This site also contains suggestions for assessment and ideas for extending the lesson.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_17");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return 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class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_18");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a onClick='return showDiv("page_5");' href="#">5</a> <a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <a onClick='return showDiv("page_8");' href="#">8</a> <a onClick='return 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title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">361</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/55350730"> <span id="translatedtitle">Geologic Mapping of Medicine Lake <span class="hlt">Volcano</span>, CA, USA</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Medicine Lake <span class="hlt">volcano</span> is a broad, shield-shaped edifice <span class="hlt">located</span> behind the main axis of the Cascade Range at its interface with the Basin and Range province in northern California. Subduction-related, but strongly influenced by an east-west extensional environment, the <span class="hlt">volcano</span> has erupted frequently during its half million year history. Approximately 250 units have been mapped, only half a dozen of</p> <div class="credits"> <p class="dwt_author">J. M. Donnelly-Nolan; D. W. Ramsey</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">362</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=GL-2002-001561&hterms=Luzon+Philippines&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3D%2522Luzon%2BPhilippines%2522"> <span id="translatedtitle">Mayon <span class="hlt">volcano</span>, southeast Luzon, Philippines</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Mayon <span class="hlt">volcano</span> is the most active <span class="hlt">volcano</span> in the Philippines, <span class="hlt">located</span> just north of the coastal town of Legaspi in southern Luzon about 325 km southeast of Manila. Mayon is a near-perfect cone; its steep, forested slopes look rather like a bull's eye when viewed from above. For scale, Mayon's circular footprint is about 16 km in diameter. This photograph was taken from the Space Shuttle on April 8, 1997. At the time the photo was taken, Mayon sported a steam plume from the summit. The lighter (non-forested) regions that radiate from the summit to the southern slopes are flows from eruptions that have occurred over the past twenty-five years. The current eruption, which started June 24, 2001, is sending flows down the southeast slope in the general direction of Legaspi. Image STS083-747-88 was provided by the by the Earth Sciences and Image Analysis Laboratory, Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">363</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/57644191"> <span id="translatedtitle"><span class="hlt">Submarine</span> slides and <span class="hlt">submarine</span> canyons on the continental slope off Canterbury, New Zealand</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The continental slope off the Canterbury Plains, New Zealand, is a progradational feature dissected by <span class="hlt">submarine</span> canyons to the north and by <span class="hlt">submarine</span> slides to the south.To the north, during lower Pleistocene sea levels, fine sand was transported from the continental shelf to the upper continental slope by strong, northward-flowing bottom currents. Mud in suspension was also carried beyond the</p> <div class="credits"> <p class="dwt_author">Richard H. Herzer</p> <p class="dwt_publisher"></p> <p class="publishDate">1979-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">364</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=submarines&pg=2&id=EJ522565"> <span id="translatedtitle">Human-Powered <span class="hlt">Submarine</span> Competition: World <span class="hlt">Submarine</span> International 1996 [and] Design Technology Exhibit: A School Model.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">Hibbard describes the process used by students at Millersville University to build a human-powered <span class="hlt">submarine</span> for entry in an international <span class="hlt">submarine</span> competition. Edwards discusses the Design Technology Exhibit held at Lu Sutton Elementary School, the purpose of which was to challenge students to design a useful structure and provide them with the…</p> <div class="credits"> <p class="dwt_author">Hibberd, John C.; Edwards, Don</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">365</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19940007565&hterms=sonar+dome&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dsonar%2Bdome"> <span id="translatedtitle">Venus small <span class="hlt">volcano</span> classification and description</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The high resolution and global coverage of the Magellan radar image data set allows detailed study of the smallest <span class="hlt">volcanoes</span> on the planet. A modified classification scheme for <span class="hlt">volcanoes</span> less than 20 km in diameter is shown and described. It is based on observations of all members of the 556 significant clusters or fields of small <span class="hlt">volcanoes</span> <span class="hlt">located</span> and described by this author during data collection for the Magellan Volcanic and Magmatic Feature Catalog. This global study of approximately 10 exp 4 <span class="hlt">volcanoes</span> provides new information for refining small <span class="hlt">volcano</span> classification based on individual characteristics. Total number of these <span class="hlt">volcanoes</span> was estimated to be 10 exp 5 to 10 exp 6 planetwide based on pre-Magellan analysis of Venera 15/16, and during preparation of the global catalog, small <span class="hlt">volcanoes</span> were identified individually or in clusters in every C1-MIDR mosaic of the Magellan data set. Basal diameter (based on 1000 measured edifices) generally ranges from 2 to 12 km with a mode of 34 km, and follows an exponential distribution similar to the size frequency distribution of seamounts as measured from GLORIA sonar images. This is a typical distribution for most size-limited natural phenomena unlike impact craters which follow a power law distribution and continue to infinitely increase in number with decreasing size. Using an exponential distribution calculated from measured small <span class="hlt">volcanoes</span> selected globally at random, we can calculate total number possible given a minimum size. The paucity of edifice diameters less than 2 km may be due to inability to identify very small volcanic edifices in this data set; however, summit pits are recognizable at smaller diameters, and 2 km may represent a significant minimum diameter related to style of volcanic eruption. Guest, et al, discussed four general types of small volcanic edifices on Venus: (1) small lava shields; (2) small volcanic cones; (3) small volcanic domes; and (4) scalloped margin domes ('ticks'). Steep-sided domes or 'pancake domes', larger than 20 km in diameter, were included with the small volcanic domes. For the purposes of this study, only volcanic edifices less than 20 km in diameter are discussed. This forms a convenient cutoff since most of the steep-sided domes ('pancake domes') and scalloped margin domes ('ticks') are 20 to 100 km in diameter, are much less numerous globally than are the smaller diameter volcanic edifices (2 to 3 orders of magnitude lower in total global number), and do not commonly occur in large clusters or fields of large numbers of edifices.</p> <div class="credits"> <p class="dwt_author">Aubele, J. C.</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">366</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1993LPI....24...47A"> <span id="translatedtitle">Venus small <span class="hlt">volcano</span> classification and description</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The high resolution and global coverage of the Magellan radar image data set allows detailed study of the smallest <span class="hlt">volcanoes</span> on the planet. A modified classification scheme for <span class="hlt">volcanoes</span> less than 20 km in diameter is shown and described. It is based on observations of all members of the 556 significant clusters or fields of small <span class="hlt">volcanoes</span> <span class="hlt">located</span> and described by this author during data collection for the Magellan Volcanic and Magmatic Feature Catalog. This global study of approximately 10 exp 4 <span class="hlt">volcanoes</span> provides new information for refining small <span class="hlt">volcano</span> classification based on individual characteristics. Total number of these <span class="hlt">volcanoes</span> was estimated to be 10 exp 5 to 10 exp 6 planetwide based on pre-Magellan analysis of Venera 15/16, and during preparation of the global catalog, small <span class="hlt">volcanoes</span> were identified individually or in clusters in every C1-MIDR mosaic of the Magellan data set. Basal diameter (based on 1000 measured edifices) generally ranges from 2 to 12 km with a mode of 34 km, and follows an exponential distribution similar to the size frequency distribution of seamounts as measured from GLORIA sonar images. This is a typical distribution for most size-limited natural phenomena unlike impact craters which follow a power law distribution and continue to infinitely increase in number with decreasing size. Using an exponential distribution calculated from measured small <span class="hlt">volcanoes</span> selected globally at random, we can calculate total number possible given a minimum size. The paucity of edifice diameters less than 2 km may be due to inability to identify very small volcanic edifices in this data set; however, summit pits are recognizable at smaller diameters, and 2 km may represent a significant minimum diameter related to style of volcanic eruption. Guest, et al, discussed four general types of small volcanic edifices on Venus: (1) small lava shields; (2) small volcanic cones; (3) small volcanic domes; and (4) scalloped margin domes ('ticks'). Steep-sided domes or 'pancake domes', larger than 20 km in diameter, were included with the small volcanic domes. For the purposes of this study, only volcanic edifices less than 20 km in diameter are discussed. This forms a convenient cutoff since most of the steep-sided domes ('pancake domes') and scalloped margin domes ('ticks') are 20 to 100 km in diameter, are much less numerous globally than are the smaller diameter volcanic edifices (2 to 3 orders of magnitude lower in total global number), and do not commonly occur in large clusters or fields of large numbers of edifices.</p> <div class="credits"> <p class="dwt_author">Aubele, J. C.</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">367</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/12265881"> <span id="translatedtitle">Eruptive history and tectonic setting of Medicine Lake <span class="hlt">Volcano</span>, a large rear-arc <span class="hlt">volcano</span> in the southern Cascades</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Medicine Lake <span class="hlt">Volcano</span> (MLV), <span class="hlt">located</span> in the southern Cascades ?55 km east-northeast of contemporaneous Mount Shasta, has been found by exploratory geothermal drilling to have a surprisingly silicic core mantled by mafic lavas. This unexpected result is very different from the long-held view derived from previous mapping of exposed geology that MLV is a dominantly basaltic shield <span class="hlt">volcano</span>. Detailed mapping shows</p> <div class="credits"> <p class="dwt_author">Julie M. Donnelly-Nolan; Timothy L. Grove; Marvin A. Lanphere; Duane E. Champion; David W. Ramsey</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">368</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007AGUFM.V34B..07E"> <span id="translatedtitle">Preliminary Results of a Near-Bottom Integrated Seafloor and Water Column survey of Brothers <span class="hlt">volcano</span>, Kermadec arc, Using the Autonomous Vehicle ABE</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Brothers <span class="hlt">volcano</span>, <span class="hlt">located</span> about 310 km NE of New Zealand along the magmatic front of the Kermadec arc, is one of the best studied intraoceanic arc <span class="hlt">submarine</span> <span class="hlt">volcanoes</span>. Its 3.0 x 3.5 km caldera is slightly elliptical, with the long axis oriented about N320°E and has more than 300 m relief from a rim at ~1500 m to a maximum depth of 1880 m in its NW corner. Two major hydrothermal systems were discovered on it in the late 1990s, a high temperature field (up to 302°C) on the NW wall and a lower temperature gas-rich system on the summits of a pair of dacitic cones that occupy the SE half of the caldera. Although the caldera and cones were partly explored by submersibles in 2004 and 2005, the base map, made with a surface ship multibeam, was not detailed enough to understand the context of the seafloor observations. We used the autonomous vehicle ABE launched and recovered from the R/V SONNE in July-August 2007 to conduct high resolution near-bottom surveys of the caldera and its hydrothermal systems using a multibeam sonar, magnetometer, and CTD. The caldera wall, the dacite cones and part of the flat caldera rim were mapped in 96 hours of survey time over 8 dives. In addition, very detailed water column surveys at lower altitude and closer line spacing were conducted over the two most intense hydrothermal sites (i.e., the NW caldera wall and the smaller dacite cone). Although the results are preliminary, there are obvious correlations between hydrothermal activity, wall geomorphology, structural lineations, and the magnetic signature. New hydrothermal sites were discovered on the uppermost NW rim of the caldera and on the SW wall. This new map, along with the previously collected suites of fluid, mineral and seafloor observations, provides a baseline for future monitoring of Brothers' hydrothermal and volcanic activity. It will also provide a better understanding of how the long-term interplay of hydrothermal and volcanic activity affects the geomorphic evolution of <span class="hlt">submarine</span> arc <span class="hlt">volcanoes</span>.</p> <div class="credits"> <p class="dwt_author">Embley, R. W.; de Ronde, C.; Davy, B.; Baker, E. T.; Resing, J. A.; Yoerger, D. R.; Merle, S. G.; Walker, S. L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">369</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008AGUFM.V13D2147P"> <span id="translatedtitle">U-Th/He Ages of HSDP-2 <span class="hlt">Submarine</span> Samples</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Hawaiian lavas have been used to investigate the life-cycles of hotspot-traversing <span class="hlt">volcanoes</span>. The ~ 3500m core recovered by the Hawaii Scientific Drill Project, phase 2 (HSDP-2) has proven invaluable in refinement of models that link plume structures and melting rates to subaerial growth and geochemical evolution. Accurate age dating of lavas is critical in linking geochemical observations to plume characteristics; however, young ages and potassium-poor lavas limit the precision of argon methods. The U-Th/He method on olivine phenocrysts has been used to successfully date Hawaiian post-shield alkali basalts and flood basalts from the Snake River Plain. We are applying the method to olivine-rich lithologies in the HSDP-2 core in an attempt to gain further information about the growth rates of Hawaiian <span class="hlt">volcanoes</span>. Preliminary results indicate that the method could help refine the flow chronology, but that modifications to the analysis procedure may be necessary to optimize the results. A subaerial Mauna Kea tholeiitic basalt from 528m depth yields a U-Th/He age of 485 +/- 100 ka (sample SR0222), slightly older than expected based on previous determinations on stratigraphically bounding flows by the argon isochron method (Sharp et al., Gcubed, 2005). A <span class="hlt">submarine</span> hyaloclastite sample from 2931m depth (SR930) yields a preliminary age of 650+/-100 ka, which agrees well with previous Ar measurements. A pillow lava, SR0964, was also investigated, but it yielded a complicated He release pattern and no age can be obtained. U and Th concentrations in olivine separates from all three samples are low (2.6 - 5.2 ppb U; 4.5 - 8.0 ppb Th). The <span class="hlt">submarine</span> samples appear to have a substantial amount of magmatic helium still remaining in the olivine after in vacuo crushing, as evidenced by high R/Ra values in gas released at high temperature. Residual gas left after crushing may be up to 85% magmatic, which makes the determination of radiogenic He less accurate. Sulfur contents of glass from the host <span class="hlt">submarine</span> lava samples are high, indicating that the lavas were incompletely degassed. Helium isotopic ratios measured from the crushing step are within error of previously published values (R/Ra = 12.4 and 12.9). Extreme R/Ra values in the 530° C pre-fusion extraction (R/Ra = 756 for SR0964 and 68 for SR0930) suggest that high-T degassing may preferentially release 3He. We are continuing a helium isotopic exploration of the lowermost 450m of HSDP-2, which will provide important information about He isotopes in the core of the Hawaiian plume, and focusing further U- Th/He investigations on samples with low-S glass.</p> <div class="credits"> <p class="dwt_author">Peterson, B. T.; Aciego, S. M.; Kennedy, B. M.; Depaolo, D. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">370</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFM.P23C1946P"> <span id="translatedtitle">Identification of topographic fingerprints of eruption environments: Geomorphometric evidence from <span class="hlt">volcanoes</span> of the Reykjanes Peninsula, Iceland</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The geomorphometry of <span class="hlt">volcanoes</span> provides important information on the geologic evolution of planets. Therefore, constraining the topographic characteristics of terrestrial <span class="hlt">volcanoes</span> is an important step for comparative planetology. Here we resolve geomorphometric fingerprints of volcanic edifices formed in subaerial, <span class="hlt">submarine</span> and subglacial environments by focusing on <span class="hlt">volcanoes</span> of the Reykjanes Peninsula, Iceland. The Reykjanes Volcanic Belt connects the Reykjanes midoceanic spreading ridge with the Western volcanic zone. It consists of four volcanic systems that display a variety of pristine Quaternary <span class="hlt">submarine</span>, subglacial and subaerial volcanic edifices. 35 edifices were chosen for quantitative characterization using the IS 50V digital elevation model (20m/pixel). The edifice boundaries were delimited by concave breaks in slope around their bases and edifices were grouped according to slope, size and shape. A division based on slope values proves successful in discriminating subaerial edifices from subglacial and <span class="hlt">submarine</span> edifices. Subaerial shields have average slopes between 2.8°-6.5°, which is at least 6° less than the average slopes of <span class="hlt">submarine</span> and subglacial edifices. Moreover, the shields can be sub-divided into tholeite (2.8°-4.6°) and picrite (5.3°-6.5°) shields based on average slope. <span class="hlt">Submarine</span> and subglacial edifices cannot be distinguished from each other by average slopes, and were grouped together in a <span class="hlt">submarine</span> and subglacial class. This class was sub-divided into 3 groups based on their volume and suggests an evolutionary growth trend starting with small elliptical, linear ridges (~2*10-3-7*10-3 km3) to flat topped, table-shaped mountains (~100*10-3 -640*10-3 km3), with an intermediate growth stage (~10*10-3 - 80*10-3 km3) of very variable and irregular complex edifices. Further analysis of topographic profiles, slope frequency and elevational slope development, show that it is possible to resolve individual land elements based on break in slope, such as lava cap, hyaloclastite apron, hyaloclastite slope and hyaloclastite summit. The boundary between hyaloclastite breccia and lava cap represents a passage zone that marks late-stage subaerial lava-fed deltas and is clearly defined by convex breaks in slope. Large elevation changes in the passage zone is diagnostic of lava deltas emplaced in a glacial environment, and thus mapping of elevation changes of convex breaks in slope is a potential tool for distinguishing big table-shaped volcanic edifices emplaced in a <span class="hlt">submarine</span> or subglacial environment. This study shows that <span class="hlt">volcano</span> morphometry can be used to obtain information on processes operating during <span class="hlt">volcano</span> construction, its eruption environment and the resulting evolutionary growth trends. A significant advantage of this method is its application for remote and inaccessible areas such as <span class="hlt">submarine</span> or subglacial environments as well as extraterrestrial planets. Moreover, the break in slope delimitation of edifice bases and the possibility of resolving individual landform elements makes this geomorphometric analysis directly applicable for advanced mapping techniques such as object-based image analysis.</p> <div class="credits"> <p class="dwt_author">Pedersen, G. B.; Grosse, P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">371</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2001AGUFM.T42B0938K"> <span id="translatedtitle">The Leading Edge of the Galapagos Hotspot: Geochemistry and Geochronology of <span class="hlt">Submarine</span> Glasses Coupled to New Sidescan Sonar Imagery</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Fernandina, the western-most <span class="hlt">volcano</span> in the Galapagos archipelago, is at the leading edge of the hotspot with respect to plate motion. Recent mapping of the ocean floor west of Fernandina (on R/V Revelle, using the HMRG towed sidescan sonar MR1, and Simrad EM120 multibeam) provides a dramatic new view of the volcanic constructional processes that have created the islands. The western flank of the <span class="hlt">volcano</span> is characterized by the prominent Northwest, West, and Southwest rift zones, which are constructed of hummocky pillow lavas. Older lava flow terrain is distinguished by weaker acoustic return, whereas extensive younger flows are characterized by strong backscatter patterns with distinctive flow-like margins. MR1 sidescan sonar mapping provides an important new geologic and stratigraphic context for understanding the <span class="hlt">submarine</span> Galapagos platform, particularly from a geochemical perspective. Fernandina lavas have high 3He/4He ratios, up to 29 times atmospheric, and solar-like neon isotopic compositions, characteristics which suggest they are derived from the deep mantle. The high 3He/4He ratios, and rapid eruption rates at Fernandina also indicate that it lies directly above the center of the Galapagos hotspot. In order to place these geochemical data into a chronological framework, we have determined ages for Fernandina <span class="hlt">submarine</span> glasses using the Th-U-He crushing/melting disequilibrium method. Preliminary Th-U-He ages (from the 2000 R/V Melville AHA-Nemo expedition), combined with the new MR1 sonar mapping, shows that the rift zones are characterized by extremely young ages (0 to 30 Ka) while older <span class="hlt">submarine</span> lava flows with lower acoustic backscatter have significantly older ages ( ~ 100 Ka). The geochronological data, and the geological context from the side-scan sonar, provide new evidence for <span class="hlt">volcano</span> growth rates in oceanic hotspot provinces, and will be used to determine the growth rate of the Galapagos platform.</p> <div class="credits"> <p class="dwt_author">Kurz, M. D.; Fornari, D. J.; Geist, D. J.; Johnson, P. D.; Curtice, J. M.; Lott, D. E.; Harpp, K.; Saal, A. E.; Peckman, U. G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">372</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004JGRC..109.1002D"> <span id="translatedtitle">Hydroplaning and <span class="hlt">submarine</span> debris flows</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Examination of <span class="hlt">submarine</span> clastic deposits along the continental margins reveals the remnants of holocenic or older debris flows with run-out distances up to hundreds of kilometers. Laboratory experiments on subaqueous debris flows, where typically one tenth of a cubic meter of material is dropped down a flume, also show high velocities and long run-out distances compared to subaerial debris flows. Moreover, they show the tendency of the head of the flow to run out ahead of the rest of the body. The experiments reveal the possible clue to the mechanism of long run-out. This mechanism, called hydroplaning, begins as the dynamic pressure at the front of the debris flow becomes of the order of the pressure exerted by the weight of the sediment. In such conditions a layer of water can intrude under the sediment with a lubrication effect and a decrease in the resistance forces between the sediment and the seabed. A physical-mathematical model of hydroplaning is presented and investigated numerically. The model is applied to both laboratory- and field-scale debris flows. Agreement with laboratory experiments makes us confident in the extrapolation of our model to natural flows and shows that long run-out distances can be naturally attained.</p> <div class="credits"> <p class="dwt_author">de Blasio, Fabio V.; Engvik, Lars; Harbitz, Carl B.; ElverhøI, Anders</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">373</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://learningcenter.nsta.org/product_detail.aspx?id=10.2505/4/ss05_028_06_54"> <span id="translatedtitle">Tech trek: Viewing <span class="hlt">volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">Help students make real-world connections to Earth science concepts such as <span class="hlt">volcanoes</span> with the help of modern technology. This article enumerates several websites where students can explore these forces of nature in a variety of ways - all from a safe distance!</p> <div class="credits"> <p class="dwt_author">Christmann, Edwin P.; Wighting, Mervyn J.; Lucking, Robert A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">374</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19880020302&hterms=history+volcanoes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dhistory%2Bvolcanoes"> <span id="translatedtitle"><span class="hlt">Volcano</span> evolution on Mars</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The diversity of volcanic activity on Mars throughout geologic time was one of the major factors that has controlled the spatial distribution of surface mineralogies. The traditional view of Martian volcanism is one in which effusive activity has dominated the entire preserved geologic history of the planet, with the minor exception of phreatomagnetic activity and associated <span class="hlt">volcano</span> ground-ice interactions. However, two lines of evidence have caused reconsidering of this view, and have led to the possible role of explosive volcanism on Mars. First, detailed analysis of high resolution Viking Orbiter images has provided good evidence for explosive activity on Hecates Tholus and Alba Patera. Secondly, the problems believed to exist in associating explosive volcanism with silicic magmas on Mars, and the consequent unusual magmatic evolutionary trend for Martian <span class="hlt">volcanoes</span> from silica-rich to silica-poor, may now be circumvented by the consideration of basatic plinian activity similar in kind to terrestrial eruptions such as the 1886 Tarawera eruption. The morphologic evidence for an early phase of explosive activity on Mars is briefly reviewed, and a model is presented for the emplacement of ash-flow deposits on Martian <span class="hlt">volcanoes</span>. The <span class="hlt">volcanoes</span> Alba Patera and Olympus Mons are considered in this context, along with some of the older Martian tholi and paterae</p> <div class="credits"> <p class="dwt_author">Mouginis-Mark, Pete; Wilson, Lionel</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">375</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.knowitall.org/nasa/pdf/scifiles/redlight_full.pdf#page=52"> <span id="translatedtitle">The Three Little <span class="hlt">Volcanoes</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" hre