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1

Moloka'i Fieldtrip Guidebook: Selected Aspects of the Geology, Geography, and Coral Reefs of Moloka'i  

USGS Publications Warehouse

This guidebook was compiled with the express purpose of describing the general geology of Moloka'i and those locations with significance to the U.S. Geological Survey's study of Moloka'i's coral reef, a part of the U.S. Department of Interior's 'Protecting the Nation's Reefs' program. The first portion of the guidebook describes the island and gives the historical background. Fieldtrip stop locations are listed in a logical driving order, essentially from west to east. This order may be changed, or stops deleted, depending on time and scheduling of an individual fieldtrip.

Cochran, Susan A.; Roberts, Lucile M.; Evans, Kevin R.

2002-01-01

2

The East Java mud volcano (2006 to present): An earthquake or drilling trigger?  

Microsoft Academic Search

On May 29th 2006 a mud volcano, later to be named ‘Lusi’, started to form in East Java. It is still active and has displaced >30,000 people. The trigger mechanism for this, the world's largest and best known active mud volcano, is still the subject of debate. Trigger mechanisms considered here are (a) the May 27th 2006 Yogyakarta earthquake, (b)

Richard J. Davies; Maria Brumm; Michael Manga; Rudi Rubiandini; Richard Swarbrick; Mark Tingay

2008-01-01

3

Cyclic activity of the LUSI mud volcano (East Java, Indonesia)  

NASA Astrophysics Data System (ADS)

Mud volcanoes often release fluids in a pulsating fashion, with periodic timescales ranging from minutes to days. These oscillations, common in natural systems of multi-phase fluid flow, are thought to result from some combination of complex feedback mechanisms between conduit and source geometry, and such factors as: fluid compressibility, viscosity and density, changes in lithostatic stresses, reservoir pressure, or vent conditions. The LUSI mud volcano is in a densely populated district of the Sidoarjo regency (East Java, Indonesia), and has been erupting since May 2006. Crisis management workers and local residents have reported observations of pulsating eruptive cycles lasting a few hours during the first two years of the eruption, and possibly beyond. Since 2010, however, the activity has shifted to individual transient eruptions recurring at intervals of a few minutes. In the summer of 2011, we documented this cyclic behavior at LUSI using a combination of high-resolution time-lapse photography, webcam, and thermal infrared imagery. The imagery reveals that hot mud and gases were released from three individual sources within the 150 m wide vent pond. The mud, consisting of at least 70% water, is erupted at temperatures close to boiling. Released gases consist principally of water vapor, carbon dioxide and methane. Eruptions ejected mud some 20 m above the vent in an unsteady fountain and formed 50 m-high plumes of hot gas. Pulses, on average 50 s in duration, were characterized by sharp onsets and exponential decays in intensity. We observed explosion periods ranging from 1 to 3 minutes during this campaign, the median period was 100 s, and pulses were separated by periods of apparent quiescence. Each vent was characterized by a different dominant period, indicating that parameters controlling activity vary among the vents. Potential conceptual eruptive models are gas accumulation and release, slug flow, or oscillations in pressure at depth to account for the eruption cyclicity. Our field measurements of periodicity, column height and, in time, gas flux, coupled with estimates of mud viscosity and conduit geometry, are thus crucial parameters that can be used to test the various models and ultimately constrain conditions in the deeper parts of the LUSI system.

Vanderkluysen, L.; Clarke, A. B.; Hartnett, H. E.

2011-12-01

4

New geophysical views of Mt.Melbourne Volcano (East Antarctica)  

NASA Astrophysics Data System (ADS)

Mt. Melbourne volcano is located along the transition between the Transantarctic Mountains and the West Antarctic Rift System. Recent volcanic activity is suggested by the occurrence of blankets of pyroclastic pumice and scoria fall around the eastern and southern flanks of Mt Melbourne and by pyroclastic layers interbedded with the summit snows. Geothermal activity in the crater area of Mount Melbourne may be linked to the intrusion of dykes within the last 200 years. Geophysical networks suggest that Mount Melbourne is a quiescent volcano, possibly characterised by slow internal dynamics. During the 2002-2003 Italian Antarctic campaign a high-resolution aeromagnetic survey was performed within the TIMM (Tectonics and Interior of Mt. Melbourne area) project. This helicopter-borne survey was flown at low-altitude and in drape-mode configuration (305 m above terrain) with a line separation less than 500 m. Our new high-resolution magnetic maps reveal the largely ice-covered magmatic and tectonic patters in the Mt. Melbourne volcano area. Additionally, in the frame of the UK-Italian ISODYN-WISE project (2005-06), an airborne ice-sounding radar survey was flown. We combine the sub-ice topography with images and models of the interior of Mt. Melbourne volcano, as derived from the high resolution aeromagnetic data and land gravity data. Our new geophysical maps and models also provide a new tool to study the regional setting of the volcano. In particular we re-assess whether there is geophysical evidence for coupling between strike-slip faulting, the Terror Rift, and Mount Melbourne volcano.

Armadillo, E.; Gambetta, M.; Ferraccioli, F.; Corr, H.; Bozzo, E.

2009-05-01

5

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 ...

Mrs. Walls

2011-01-30

6

Modeling study of growth and potential geohazard for LUSI mud volcano: East Java, Indonesia  

E-print Network

Modeling study of growth and potential geohazard for LUSI mud volcano: East Java, Indonesia Bambang., Wisma Mulia 22nd Floor, JI. Jend. Gatot Subroto 42, 12710 Jakarta, Indonesia b Bakosurtanal, Jl. Jakarta-Bogor Km. 46, 16911 Cibinong, Indonesia c Applied Geology Research Division, Institute of Technology

Manga, Michael

7

Alaska - Russian Far East connection in volcano research and monitoring  

NASA Astrophysics Data System (ADS)

The Kurile-Kamchatka-Alaska portion of the Pacific Rim of Fire spans for nearly 5400 km. It includes more than 80 active volcanoes and averages 4-6 eruptions per year. Resulting ash clouds travel for hundreds to thousands of kilometers defying political borders. To mitigate volcano hazard to aviation and local communities, the Alaska Volcano Observatory (AVO) and the Institute of Volcanology and Seismology (IVS), in partnership with the Kamchatkan Branch of the Geophysical Survey of the Russian Academy of Sciences (KBGS), have established a collaborative program with three integrated components: (1) volcano monitoring with rapid information exchange, (2) cooperation in research projects at active volcanoes, and (3) volcanological field schools for students and young scientists. Cooperation in volcano monitoring includes dissemination of daily information on the state of volcanic activity in neighboring regions, satellite and visual data exchange, as well as sharing expertise and technologies between AVO and the Kamchatkan Volcanic Eruption Response Team (KVERT) and Sakhalin Volcanic Eruption Response Team (SVERT). Collaboration in scientific research is best illustrated by involvement of AVO, IVS, and KBGS faculty and graduate students in mutual international studies. One of the most recent examples is the NSF-funded Partnerships for International Research and Education (PIRE)-Kamchatka project focusing on multi-disciplinary study of Bezymianny volcano in Kamchatka. This international project is one of many that have been initiated as a direct result of a bi-annual series of meetings known as Japan-Kamchatka-Alaska Subduction Processes (JKASP) workshops that we organize together with colleagues from Hokkaido University, Japan. The most recent JKASP meeting was held in August 2011 in Petropavlovsk-Kamchatsky and brought together more than 130 scientists and students from Russia, Japan, and the United States. The key educational component of our collaborative program is the continuous series of international volcanological field schools organized in partnership with the Kamchatka State University. Each year more than 40 students and young scientists participate in our annual field trips to Katmai, Alaska and Mutnovsky, Kamchatka.

Izbekov, P. E.; Eichelberger, J. C.; Gordeev, E.; Neal, C. A.; Chebrov, V. N.; Girina, O. A.; Demyanchuk, Y. V.; Rybin, A. V.

2012-12-01

8

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

9

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

10

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

11

Volcanoes.  

ERIC Educational Resources Information Center

One of a series of general interest publications on science topics, this booklet provides a non-technical introduction to the subject of volcanoes. Separate sections examine the nature and workings of volcanoes, types of volcanoes, volcanic geological structures such as plugs and maars, types of eruptions, volcanic-related activity such as geysers…

Tilling, Robert I.

12

A study on the geophysical characteristics of the summit of the Dokdo volcano in the East Sea (Japan Sea)  

Microsoft Academic Search

Multi-beam, magnetic, sub-bottom profiling, and side scan sonar survey data for the eastern part of the summit area of the Dokdo volcano obtained in 1999, 2004, 2007 were analyzed to investigate the geophysical characteristics of the summit of the Dokdo. The Dokdo volcano is located in the northeastern part of the Ulleung Basin in the East Sea (Japan Sea) and

C. Kim; H. Jou; E. Jeong; H. Kim

2007-01-01

13

The 2007 eruption of Kelut volcano (East Java, Indonesia): Phenomenology, crisis management and social response  

NASA Astrophysics Data System (ADS)

We focus in this paper on the processes and consequences of an unusual volcanic eruption at Kelut volcano, East Java. In November 2007, after two months of worrying precursor signs, Kelut volcano erupted. But neither explosions nor the usual hazards observed during the historic eruptions happened (e.g. ash falls, volcanic bombs and pyroclastic flows). Instead of an explosive eruption, the 2007 eruption was extrusive. Given than such an eruption could not be predicted, the authorities had to manage a new situation. We conducted interviews with nine stakeholders of the crisis management team, and undertook a questionnaire-based survey in the settlement nearest to the crater, in order to understand how the authorities managed the crisis, and how people reacted. Inquiries and questionnaires were carried out shortly after the end of the evacuation process, when the volcano was still under surveillance for fear of an explosive phase. The results display a real gap in what it takes to manage a crisis or live through a crisis. This suggests that the "unusual" eruption pattern of Kelut volcano was not the only factor of the misunderstanding between the authorities and the population. These problems stem from more structural causes such as the lack of communication and information when there is a need to adapt to a new scenario. In such a situation, the inability of the crisis management system to take decisions underscored the intrinsic vulnerability of the population despite a hierarchical and strategic top-down crisis management approach.

De Bélizal, Édouard; Lavigne, Franck; Gaillard, J. C.; Grancher, Delphine; Pratomo, Indyo; Komorowski, Jean-Christophe

2012-01-01

14

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

15

Prokaryotic community structure and diversity in the sediments of an active submarine mud volcano (Kazan mud volcano, East Mediterranean Sea).  

PubMed

We investigated 16S rRNA gene diversity at a high sediment depth resolution (every 5 cm, top 30 cm) in an active site of the Kazan mud volcano, East Mediterranean Sea. A total of 242 archaeal and 374 bacterial clones were analysed, which were attributed to 38 and 205 unique phylotypes, respectively (> or = 98% similarity). Most of the archaeal phylotypes were related to ANME-1, -2 and -3 members originating from habitats where anaerobic oxidation of methane (AOM) occurs, although they occurred in sediment layers with no apparent AOM (below the sulphate depletion depth). Proteobacteria were the most abundant and diverse bacterial group, with the Gammaproteobacteria dominating in most sediment layers and these were related to phylotypes involved in methane cycling. The Deltaproteobacteria included several of the sulphate-reducers related to AOM. The rest of the bacterial phylotypes belonged to 15 known phyla and three unaffiliated groups, with representatives from similar habitats. Diversity index H was in the range 0.56-1.73 and 1.47-3.82 for Archaea and Bacteria, respectively, revealing different depth patterns for the two groups. At 15 and 20 cm below the sea floor, the prokaryotic communities were highly similar, hosting AOM-specific Archaea and Bacteria. Our study revealed different dominant phyla in proximate sediment layers. PMID:20370830

Pachiadaki, Maria G; Lykousis, Vasilios; Stefanou, Euripides G; Kormas, Konstantinos A

2010-06-01

16

Crustal structure of east central Oregon: relation between Newberry Volcano and regional crustal structure  

USGS Publications Warehouse

A 180-km-long seismic refraction transect from the eastern High Cascades, across Newberry Volcano, to the eastern High Lava Plains is used to investigate the subvolcanic crustal and upper mantle velocity structure there. Near-surface volcanic flows and sedimentary debris (1.6-4.7 km/s), ranging from 3 to 5 km in thickness, overlie subvolcanic Basin and Range structures. East and west of Newberry Volcano, the subvolcanic basement (5.6 km/s) has been downwarped, producing 5-km-deep basins. The midcrust (8- to 28-km depth) is characterized by velocities ranging from 6.1 to 6.5 km/s and varies laterally in thicknesses. The lower crust is characterized by an unusually high velocity (about 7.4 km/s), and its geometry mirrors the subvolcanic basement geometry. The Moho is located at a depth of 37 km and represents a transition to an upper mantle velocity of 8.1 km/s. The shallow subsurface (1.2 km) beneath Newberry Volcano is characterized by high-velocity 5.6 km/s, versus 4.1 km/s for the surrounding area) intrusions and appears to be located on a basement high. Beneath the seismic refraction array at Newberry Volcano, an absence of low-velocity anomalies suggests that large silicic magma chambers do not exist in the upper crust, but apparent high attenuation of the seismic wave field may be consistent with either partial melts in small volumes, elevated crustal temperatures, and/or poor geophone-recording site coupling. -Authors

Catchings, R.D.; Mooney, W.D.

1988-01-01

17

Shaded Relief with Height as Color, Virunga and Nyiragongo Volcanoes and the East African Rift  

NASA Technical Reports Server (NTRS)

Volcanic, tectonic, erosional and sedimentary landforms are all evident in this comparison of two elevation models of a region along the East African Rift at Lake Kivu. The area shown covers parts of Congo, Rwanda and Uganda.

These two images show exactly the same area. The image on the left was created using the best global topographic data set previously available, the U.S. Geological Survey's GTOPO30. In contrast, the much more detailed image on the right was generated with data from the Shuttle Radar Topography Mission, which collected enough measurements to map 80 percent of Earth's landmass at this level of precision. Elevation is color coded, progressing from green at the lower elevations through yellow to brown at the higher elevations. A false sun in the northwest (upper left) creates topographic shading.

Lake Kivu is shown as black in the Shuttle Radar Topography Mission version (southwest corner). It lies within the East African Rift, an elongated tectonic pull-apart depression in Earth's crust. The rift extends to the northeast as a smooth lava- and sediment-filled trough. Two volcanic complexes are seen in the rift. The one closer to the lake is the Nyiragongo volcano, which erupted in January 2002, sending lava toward the lake shore and through the city of Goma. East of the rift, even more volcanoes are seen. These are the Virunga volcano chain, which is the home of the endangered mountain gorillas. Note that the terrain surrounding the volcanoes is much smoother than the eroding mountains that cover most of this view, such that topography alone is a good indicator of the extent of the lava flows. But this clear only at the higher spatial resolution of the shuttle mission's data set.

For some parts of the globe, Shuttle Radar Topography Mission measurements are 30 times more precise than previously available topographical information, according to NASA scientists. Mission data will be a welcome resource for national and local governments, scientists, commercial enterprises, and members of the public alike. The applications are as diverse as earthquake and volcano studies, flood control, transportation, urban and regional planning, aviation, recreation, and communications. The data's military applications include mission planning and rehearsal, modeling, and simulation.

Elevation data used in this image was acquired by the Shuttle Radar Topography Mission aboard Space Shuttle Endeavour, launched on Feb. 11,2000. The mission used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR)that flew twice on Endeavour in 1994. The Shuttle Radar Topography Mission was designed to collect 3-D measurements of Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense, and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, D.C.

Size: 1 degree latitude by 1 degree longitude (about 111 x 111 kilometers or 69 x 69 miles) Location: 1.5 degrees South latitude, 29.5 degrees East longitude Orientation: North at top Image: Elevation data, colored height with shaded relief Original Data Resolution: SRTM 1 arcsecond (about 30 meters or 98 feet), GTOPO30 no greater than 30 arcseconds (about 925 meters or 3000 feet) Date Acquired: February 2000 (SRTM), Unknown (GTOPO30)

2002-01-01

18

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.

2012-08-03

19

Origin of fluids and eruption dynamics at LUSI mud volcano (East Java, Indonesia)  

NASA Astrophysics Data System (ADS)

The LUSI mud volcano near Sidoarjo in East Java (Indonesia) has been erupting mud, water and gases since May 2006. It is the most recent manifestation of mud volcanism in the Sunda back-arc region, part of a larger cluster of a dozen mud volcanoes scattered across East Java and Madura. LUSI discharged as much as 180,000 cubic meters of mud per day at the peak of its activity, destroyed thousands of homes, and displaced tens of thousands of people. The erupted fluids are a mixture of water, clays, and other minerals at near-boiling temperatures, accompanied by the bursting of gas bubbles on average every 1-3 minutes, which trigger mud fountains ~20 m in height. We have taken a multi-disciplinary approach to assess both the fluid provenance and eruption behavior at this complex and evolving mud volcano, by using a combination of absorption infrared spectrometry of the gases, X-Ray diffraction of the solid fraction, major and trace element analyses of solids and dissolved ions in liquids, and isotopic analyses of separated water (D/H and 87Sr/86Sr). Similar analyses of other regional fluid sources (hot springs, surface waters, sea water, and relict mud volcanoes) were also carried out for comparison. From open path FTIR measurements, we determine that the gases released during explosions at LUSI consist of 98% water vapor, 1.5% carbon dioxide, and 0.5% methane, with corresponding fluxes of 2,300 t/yr of CH4, 30,000 t/yr of CO2 and 800,000 t/yr of water vapor. The methane flux is two orders of magnitude larger than estimates for any other single mud volcano on Earth. By comparing the mineral composition of solids present in the mud to rock outcrops of the local stratigraphy, the solids can be traced with some certainty to the blue-gray clays of the Upper Kalibeng formation, found 1600-1800 m beneath the LUSI main vent. However, the water content and chemical composition of the liquid phase are more difficult to interpret. The LUSI fluids are compositionally distinct from all the other sources we measured to date, including some of the older mud volcanoes, suggesting that the underlying water source for LUSI is different. Our major and trace element data suggest the water and solids in the LUSI fluid may not originate from the same geologic formation, providing indirect evidence in support of more complex geophysical models of the eruption. Based on our oxygen and deuterium isotope data, the LUSI fluids reflect high-temperature water-rock interactions, and the isotopic composition of the water does not appear to have changed between 2006 and 2008, despite some evidence suggesting that the mass ratio of particles to water in the mud itself has changed since the eruption began.

Vanderkluysen, L.; Hartnett, H. E.; Clarke, A. B.; Burton, M. R.

2013-12-01

20

Periodic gas release from the LUSI mud volcano (East Java, Indonesia)  

NASA Astrophysics Data System (ADS)

The LUSI mud volcano has been erupting since May 2006 in a densely populated district of the Sidoarjo regency (East Java, Indonesia), forcing the evacuation of 40,000 people and destroying industries, farmlands, and 10,000 homes. Peak mud extrusion rates of 180,000 m3/d were measured in the first few months of the eruption, which have decreased to <20,000 m3/d in 2012. Mud volcanoes often release fluids in a pulsating fashion, with periodic timescales ranging from minutes to days, and LUSI is no exception. These oscillations, common in natural systems of multi-phase fluid flow, are thought to result from some combination of complex feedback mechanisms between conduit and source geometry, fluid compressibility, viscosity and density, changes in lithostatic stresses, reservoir pressure, fluid phases or vent conditions. Crisis management workers and local residents reported observations of pulsating eruptive cycles lasting a few hours during the first two years of the eruption, and possibly beyond. Since that time, activity has shifted to individual transient eruptions recurring at intervals of a few minutes. In May and October of 2011, we documented the periodic explosive release of fluids at LUSI using a combination of high-resolution time-lapse photography, continuous webcam, open path FTIR, and thermal infrared imagery. The mud, consisting of approximately 70% water, is erupted at temperatures close to boiling. Gases are periodically released by the bursting of bubbles approximately 3 m in diameter, triggering mud fountains ~20 m in height. No appreciable gas seepage was detected in the quiescent intervals between bubble bursts. Absorption spectrometry in the infrared spectrum reveals that the gas released during explosions consists of 98.5% water vapor, 1% carbon dioxide, and 0.3% methane. On rare occasions, minor amounts of ammonia were also detected. Using simplified plume geometries based on observations, we estimate that LUSI releases approximately 1,500 T/yr of methane, which is equivalent to 0.5% of the yearly methane production from the 2.7 million heads of cattle in the East Java province. We observed explosion periods from 1 to 3 minutes with a median period of 100 s. Two conceptual models for the periodic behavior are assessed: 1) decompressional boiling of water as fluids ascend a pathway to the surface suggests that bubbles form 10s of meters below the surface and continue to expand as they rise; periodicity results from the time to reheat the fluid in the vicinity of bubble formation and 2) gas bubbles are seeded at much greater depths where carbon dioxide exsolves from solution and coalesce in a manner similar to that of slug flow.

Vanderkluysen, L.; Burton, M. R.; Clarke, A. B.; Hartnett, H. E.; Smekens, J.

2012-12-01

21

Nd and Sr isotope systematics of Shombole volcano, East Africa, and the links between nephelinites, phonolites, and carbonatites  

Microsoft Academic Search

Nd and Sr isotope compositions of nephelinites, carbonatites, and phonolites from Shombole, a Pliocene volcano in East Africa, show that the phonolites cannot be derived by simple fractional crystallization of nephelinite magma. For a given initial 87Sr\\/86Sr ratio, 143Nd\\/144Nd is lower in most phonolites than in the nephelinites and carbonatites. Interaction between nephelinitic magma and lower-crustal granulites can account for

Keith Bell; Tony Peterson

1991-01-01

22

U-series Chronology of volcanoes in the Central Kenya Peralkaline Province, East African Rift  

NASA Astrophysics Data System (ADS)

We are studying the East African Rift System (EARS) in the Central Kenya Peralkaline Province (CKPP), and specifically the young volcanoes Mt. Suswa, Longonot, and Menengai. Ar dates by Al Deino on K-feldspar phenocrysts show a strong correlation between older Ar ages and decreasing 230Th/232Th, which we interpret to reflect the age of eruption. This system has been the subject of recent research done by several UTEP alumni including Antony Wamalwa using potential field and magnetotelluric (MT) data to identify and characterize fractures and hydrothermal fluids. Also research on geochemical modeling done by John White, Vanessa Espejel and Peter Omenda led to the hypothesis of possible disequilibrium in these young, mainly obsidian samples in their post eruptive history. A pilot study of 8 samples, (also including W-2a USGS standard and a blank) establish the correlation that was seen between the ages found by Deino along with the 230/232Th ratios. All 8 samples from Mt. Suswa showed a 234U/238U ratio of (1) which indicates secular equilibrium or unity and that these are very fresh samples with no post-eruptive decay or leaching of U isotopes. The pilot set was comprised of four samples from the ring-trench group (RTG) with ages ranging from 7ka-present, two samples from the post-caldera stage ranging from 31-10ka, one sample from the syn-caldera stage dated at 41ka, and one sample from the pre-caldera stage dated at 112ka. The young RTG had a 230/232Th fractionation ratio of 0.8 ranging to the older pre-caldera stage with a 230/232Th ratio of 0.6. From this current data and research of 14C ages by Nick Rogers, the data from Longonot volcano was also similar to the 230/232Th ratio we found. Rogers' data places Longonot volcano ages to be no more than 20ka with the youngest samples also roughly around 0.8 disequilibrium. These strong correlations between the pilot study done for Mt. Suswa, 40Ar ages by Deino, along with 14C ages from Rogers have led to the exploration of present U-series data set of the youngest samples from the rest of the CKPP volcanoes including: Menengai, more from Longonot, and Olkaria. And since it is observed that there is the presence of lateral migration along an axial dike swarm that has operated in other parts of the EARS, we have chosen to run samples from the adjacent mafic fields of Elmenteita, Tandamara, and Ndabibi to see if there is a trend in the correlation of the 230/232Th ratios at the time of eruption as well as observing how close these samples get to unity. This would answer questions as to whether similar 230/232Th ratios imply that the mafic fields feed the calderas.

Negron, L. M.; Ma, L.; Deino, A.; Anthony, E. Y.

2012-12-01

23

Late Quaternary tephrostratigraphy of Baegdusan and Ulleung volcanoes using marine sediments in the Japan Sea/East Sea  

NASA Astrophysics Data System (ADS)

Only Ulleung and Baegdusan volcanoes have produced alkaline tephras in the Japan Sea/East Sea during the Quaternary. Little is known about their detailed tephrostratigraphy, except for the U-Oki and B-Tm tephras. Trace element analysis of bulk sediments can be used to identify alkaline cryptotephra because of the large compositional contrast. Five sediment cores spanning the interval between the rhyolitic AT (29.4 ka) and Aso-4 (87 ka) tephras were analyzed using an INAA scanning method. Source volcanoes for the five detected alkaline cryptotephra were identified from major element analyses of hand-picked glass shards: Ulleung (U-Ym, and the newly identified U-Sado), and Baegdusan (B-J, and the newly identified B-Sado and B-Ym). The eruption ages of the U-Ym, U-Sado, B-J, B-Sado, and B-Ym tephras are estimated to be 38 ka, 61 ka, 26 ka, 51 ka, 68-69 ka, and 86 ka, respectively, based on correlations with regional-scale TL (thinly laminated) layer stratigraphy (produced by basin-wide changes in bottom-water oxygen levels in response to millennium-scale paleoclimate variations). This study has allowed construction of an alkaline tephrostratigraphical framework for the late Quaternary linked to global environmental changes in the Japan Sea/East Sea, and improves our knowledge of the eruptive histories of Ulleung and Baegdusan volcanoes.

Lim, Chungwan; Toyoda, Kazuhiro; Ikehara, Ken; Peate, David W.

2013-07-01

24

Composition and flux of explosive gas release at LUSI mud volcano (East Java, Indonesia)  

NASA Astrophysics Data System (ADS)

LUSI mud volcano has been erupting since May 2006 in the densely populated Sidoarjo regency (East Java, Indonesia), forcing the evacuation of 40,000 people and destroying industry, farmland, and over 10,000 homes. Mud extrusion rates of 180,000 m3 d-1 were measured in the first few months of the eruption, decreasing to a loosely documented <20,000 m3 d-1 in 2012. The last few years of activity have been characterized by periodic short-lived eruptive bursts. In May and October 2011, we documented this activity using high-resolution time-lapse photography, open-path FTIR, and thermal infrared imagery. Gases (98% water vapor, 1.5% carbon dioxide, 0.5% methane) were periodically released by the bursting of bubbles approximately 3 m in diameter which triggered mud fountains to ˜10 m and gas plumes to hundreds of meters above the vent. During periods of quiescence (1-3 min), no appreciable gas seepage occurred. We estimate that LUSI releases approximately 2300 t yr-1 of methane, 30,000 t yr-1 of CO2, and 800,000 t yr-1 of water vapor. Gas bubble nucleation depths are >4000 m for methane and approximately 600 m for carbon dioxide; however, the mass fractions of these gases are insufficient to explain the observed dynamics. Rather, the primary driver of the cyclic bubble-bursting activity is decompressional boiling of water, which initiates a few tens of meters below the surface, setting up slug flow in the upper conduit. Our measured gas flux and conceptual model lead to a corresponding upper-bound estimate for the mud-water mass flux of 105 m3 d-1.

Vanderkluysen, Loïc; Burton, Michael R.; Clarke, Amanda B.; Hartnett, Hilairy E.; Smekens, Jean-François

2014-07-01

25

The mythos of dwelling : a settlement at Kalaupapa, Molokai  

E-print Network

This thesis is the exploration of the physical and metaphorical potential of one of the most beautiful and poignant places in the world. It is Kalaupapa, a peninsula on the North Shore of Molokai, Hawaii, and the site of ...

Ries, Paul R

1989-01-01

26

Selected time-lapse movies of the east rift zone eruption of K?lauea Volcano, 2004–2008  

USGS Publications Warehouse

Since 2004, the U.S. Geological Survey's Hawaiian Volcano Observatory has used mass-market digital time-lapse cameras and network-enabled Webcams for visual monitoring and research. The 26 time-lapse movies in this report were selected from the vast collection of images acquired by these camera systems during 2004–2008. Chosen for their content and broad aesthetic appeal, these image sequences document a variety of flow-field and vent processes from K?lauea's east rift zone eruption, which began in 1983 and is still (as of 2011) ongoing.

Orr, Tim R.

2011-01-01

27

Quantitative morphology of a fringing reef tract from high-resolution laser bathymetry: Southern Molokai, Hawaii  

USGS Publications Warehouse

High-resolution Scanning Hydrographic Operational Airborne Lidar Survey (SHOALS) laser-determined bathymetric data were used to define the morphology of spur-and-groove structures on the fringing reef off the south coast of Molokai, Hawaii. These data provide a basis for mapping and analyzing morphology of the reef with a level of precision and spatial coverage never before attained. An extensive fringing coral reef stretches along the central two-thirds of Molokai's south shore (???40 km); along the east and west ends there is only a thin veneer of living coral with no developed reef complex. In total, ???4800 measurements of spur-and-groove height and the distance between adjacent spur crests (wavelength) were obtained along four isobaths. Between the 5m and 15m isobaths, the mean spur height increased from 0.7 m to 1.6 m, whereas the mean wavelength increased from 71 m to 104 m. Reef flat width was found to exponentially decrease with increasing wave energy. Overall, mean spur-and-groove height and wavelength were shown to be inversely proportional to wave energy. In high-energy environments, spur-and-groove morphology remains relatively constant across all water depths. In low-energy environments, however, spur-and-groove structures display much greater variation; they are relatively small and narrow in shallow depths and develop into much larger and broader features in deeper water. Therefore, it appears that waves exert a primary control on both the small and large-scale morphology of the reef off south Molokai.

Storlazzi, C.D.; Logan, J.B.; Field, M.E.

2003-01-01

28

Reconnaissance gas measurements on the East Rift Zone of Kilauea Volcano, Hawai'i by Fourier transform infrared spectroscopy  

USGS Publications Warehouse

We report the results of a set of measurements of volcanic gases on two small ground level plumes in the vicinity of Pu`u `O`o cone on the middle East Rift Zone (ERZ) of Kilauea volcano, Hawai`i on 15 June 2001 using open-path Fourier transform infrared (FTIR) spectroscopy. The work was carried out as a reconnaissance survey to assess the monitoring and research value of FTIR measurements at this volcano. Despite representing emissions of residual volatiles from lava that has undergone prior degassing, the plumes contained detectable amounts of CO2, CO, SO2, HCl, HF and SiF4. Various processes, including subsurface cooling, condensation of water in the atmospheric plume, oxidation, dissolution in water, and reactions with wall rocks at plume vents affect the abundance of these gases. Low concentrations of volcanic CO2 measured against a high ambient background are not well constrained by FTIR spectroscopy. Although there appear to be some differences between these gases and Pu`u `O`o source gases, ratios of HCl/SO2, HF/SO2 and CO/SO2 determined by FTIR measurements of these two small plumes compare reasonably well with earlier published analyses of ERZ vent samples. The measurements yielded emission rate estimates of 4, 11 and 4 t d-1

McGee, Kenneth A.; Elias, Tamar; Sutton, A. Jefferson; Doukas, Michael P.; Zemek, Peter G.; Gerlach, Terrence M.

2005-01-01

29

Nd and Sr isotope systematics of Shombole volcano, East Africa, and the links between nephelinites, phonolites, and carbonatites  

SciTech Connect

Nd and Sr isotope compositions of nephelinites, carbonatites, and phonolites from Shombole, a Pliocene volcano in East Africa, show that the phonolites cannot be derived by simple fractional crystallization of nephelinite magma. For a given initial {sup 87}Sr/{sup 86}Sr ratio, {sup 143}Nd/{sup 144}Nd is lower in most phonolites than in the nephelinites and carbonatites. Interaction between nephelinitic magma and lower-crustal granulites can account for these differences. The similar ranges in isotopic composition of the carbonatites and nephelinites are consistent with repeated melting events involving heterogeneous mantle. The carbonatites could have formed by immiscibility with nephelinite magma or by direct partial melting of the same mantle source(s) as the nephelinites.

Bell, K. (Carleton Univ., Ottawa, Ontario (Canada)); Peterson, T. (Geological Survey of Canada, Ottawa, Ontario (Canada))

1991-06-01

30

The origin of the potassic rock suite from Batu Tara volcano (East Sunda Arc, Indonesia)  

NASA Astrophysics Data System (ADS)

atu Tara is an active potassic volcano in the eastern Sunda arc. Its leucite-bearing rock suite can be subdivided into two groups, one less evolved with Th<20 ppm, the other more evolved with Th>20 ppm. 87Sr/ 86Sr, ?18O and trace-element systematics in the less evolved group suggests that existence of parental magmas with different mantle origins. The mantle below Batu Tara is most likely heterogeneous and several source components are involved in magma genesis. Trace element and isotopic compositions of Batu Tara and adjacent volcanoes are consistent with the involvement of a subducted sedimentary/crustal component as well as MORB and OIB mantle, the latter with geochemical characteristics comparable to the mantle underlying Muriah (Java). Melt extraction from this complex mixture is envisioned as a two-stage process: partial melts of the crust-contaminated MORB mantle mix in the mantle wedge with partial melts of OIB domains. Different mixtures of these two melts provide the parental magmas that enter the volcanic plumbing system, where crystallization, hybridization and refilling processes occur. The calcalkaline volcanoes in the arc segment show stronger signatures for a subducted crustal component than Batu Tara, which displays a greater influence from the OIB mantle source. The potassium enrichment can therefore be attributed to contributions both from the enriched mantle and from subducted crustal material. Mantle-type ?18O values of the Batu Tara magmas indicate that the mantle wedge below potassic orogenic volcanoes is not necessarily strongly enriched in 18O.

van Bergen, M. J.; Vroon, P. Z.; Varekamp, J. C.; Poorter, R. P. E.

1992-11-01

31

The geochemistry of the Dunedin Volcano, East Otago, New Zealand: Rare earth elements  

Microsoft Academic Search

A variety of alkaline lavas from the Dunedin Volcano have been analyzed for the rare earth elements (REE) La-Yb. The compositions analyzed were: basalt-hawaiite-mugearite-benmoreite; basanite, nepheline hawaiite, nepheline trachyandesite and nepheline benmoreite; trachyte; phonolite. The series from basalt to mugearite shows continuous enrichment in the REE, consistent with a crystal fractionation model involving removal of olivine and clinopyroxene. From mugearite

R. C. Price; S. R. Taylor

1973-01-01

32

November 16th 2006 Lateral Collapse of South-East Crater on Mount Etna Volcano and Hazard Implication  

NASA Astrophysics Data System (ADS)

On November 16th 2006 a sector collapse affected the unstable eastern flank of the South-East Crater (SEC) on Mount Etna Volcano. The SEC is located on the Etna volcano summit and is an active steep cone formed by alternated scoria deposits and lava flows traversed by numerous fractures. The collapse occurred during an eruptive event and was probably triggered by effusive and explosive activity on the SEC. The resulting debris avalanche involved both altered and fresh materials, including an active lava flow. The collapse produced a debris avalanche deposit emplaced on the eastern flank of the volcano, extending up to 1.1 km from the source. The deposit is formed by superimposed flow units, suggesting that it is the result of at least two discrete events, the total volume is estimated in the order of 300,000-500,000 m3. A block-facies and a matrix-facies were recognized in the field. The former is composed by blocks up to 1 meters in dimension and has maximum thickness of 4-5 meters. The matrix-facies is mainly composed by a convection-driven flow deposit consisted of fine ash produced by elutriation during emplacement of the block-facies, maximum observed thickness is 30 cm. The reconstruction of the event has been supported by numerical simulations that were executed using TITAN2D, a modeling software for granular avalanches and landslides developed by GMFG at Buffalo. This approach is also useful to estimate the area that would be affected by an eventual similar event that could interest the SEC. The area affected by the lateral collapse of the SEC is a small portion of the summit area of Mount Etna, but the fact that no one was killed or injured should be considered fortuitous. This because the summit and adjacent areas of the volcano are usually visited by several people, especially tourists, not prepared to face this type of events, which was never observed and described during the recent activity of Mount Etna. The collapse of November 16th 2006 underscores the need to prepare for similar events through scientific investigation (analysis of instability, numerical modelling of flows) and development of specific civil protection plans.

Norini, G.; Andronico, D.; de Beni, E.; Polacci, M.; Grieco, F.

2007-05-01

33

Molokai Community Needs Assessment for Agriculture Education and Training.  

ERIC Educational Resources Information Center

In order to assess the needs of agriculture (AG) education and ascertain the potential employment demand for pre-service and in-service training in agriculture over the next 5 years, Maui Community College (MCC) sent questionnaires to Molokai community businesses, inquiring about their agricultural labor demand. In December 1997, 68 questionnaires…

Pezzoli, Jean A.

34

Age and petrology of the Kalaupapa Basalt, Molokai, Hawaii ( geochemistry, Sr isotopes).  

USGS Publications Warehouse

The post-erosional Kalaupapa Basalt on East Molokai, Hawaii, erupted between 0.34 and 0.57 million years ago to form the Kalaupapa Peninsula. The Kalaupapa Basalt ranges in composition from basanite to lava transitional between alkalic and tholeiitic basalt. Rare-earth and other trace-element abundances suggest that the Kalaupapa Basalt could be generated by 11-17% partial melting of a light-REE-enriched source like that from which the post-erosional lavas of the Honolulu Group on Oahu were generated by 2-11% melting. The 87Sr/86Sr ratios of the lavas range from 0.70320 to 0.70332, suggesting that the variation in composition mainly reflects variation in the melting process rather than heterogeneity of sources. The length of the period of volcanic quiescence that preceded eruption of post-erosional lavas in the Hawaiian Islands decreased as volcanism progressed from Kauai toward Kilauea. - Authors

Clague, D.A.

1982-01-01

35

Trace element and isotopic geochemistry of lavas from Haleakala Volcano, east Maui, Hawaii: Implications for the origin of Hawaiian basalts  

NASA Astrophysics Data System (ADS)

Haleakala volcano on East Maui, Hawaii, consists of a tholeiitic basalt shield which grades into a younger alkalic series that was followed by a posterosional alkalic series. Tholeiitic, transitional, and alkalic basalts range widely in Sr and Nd isotopic ratios (from mid-ocean ridge basalt to bulk earth ratios) and incompatible element (P, K, Rb, Sr, Zr, Nb, Ba, REE, Hf, Ta, and Th) abundances, but isotopic ratios and incompatible element abundance ratios (e.g., Ba/La, Nb/La, La/Ce, La/Sm) vary systematically with age. The youngest series (posterosional alkalic lavas) has the highest Rb/Sr, Ba/La, Nb/La, La/Ce, and 143Nd/144Nd ratios and the lowest 87sr/86sr ratios, whereas the oldest series (dominantly tholeiitic basalts) has the lowest Rb/Sr, Ba/La, Nb/La, La/Ce, and 143Nd/144Nd ratios and the highest 87sr/86sr ratios. The most striking features of the trace element and isotopic data are the inverse correlations between isotopic ratios and parent/daughter abundance ratios in the Sr and Nd systems. Although some of the geochemical variations can be explained by shallow level fractional crystallization (e.g., alkali basalt to mugearite [Chen et al., 1984, and manuscript in preparation, 1985]), the temporal geochemical trends require a major role for mixing. We propose a model in which melts from a diaper interact with incipient melts of its wall rocks, presumed to be oceanic lithosphere. Because of motion between the lithosphere and mantle hot spot the relative contribution of melts from the diapir (mantle plume) material to the lavas decreases with time; consequently, with decreasing age the basalts become more enriched in incompatible trace elements and acquire Sr and Nd isotopic ratios which overlap with mid-ocean ridge basalts. This model quantitatively explains the isotopic ratios and incompatible trace element abundances in representative samples from the three Haleakala volcanic series. On the basis of the degrees of melting inferred for the mixing components we conclude that the lower lithosphere and much of the asthenosphere beneath Hawaiian volcanoes are involved in creating these volcanoes.

Chen, Chu-Yung; Frey, Frederick A.

1985-09-01

36

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

37

NAME: Molokai Fish Pond & Fringing Reef Restoration LOCATION: Kaunakakai, Island of Molokai (Maui County), Hawai'i  

E-print Network

Momona (KHM) proposes to remove invasive mangroves and invasive marine algae from inside two 15th century fish ponds on the fringing reef of the Hawaiian island of Molokai. Mangroves were planted in 1902 along the shoreline and are drastically changing shoreline habitat by providing habitat for invasive

US Army Corps of Engineers

38

Ground deformation associated with the eruption of Lumpur Sidoarjo mud volcano, east Java, Indonesia  

NASA Astrophysics Data System (ADS)

Ground deformation associated with the eruption of Lumpur Sidoarjo mud volcano between 2006 and 2011 has been investigated from Synthetic Aperture Radar images. Marked subsidence has been observed to the west of, as well as around, the vent. Line-of-sight changes in the both areas decayed since the middle of 2008 with a time constant of 1.5-2.5 years, implying that the ongoing eruption won't last long. This uniform decay time indicates that the western part is connected to the eruption center since the middle of 2008 to form a system with stationary geometry. Our observation that the decay started later to the west than around the vent suggests that the subsidence to the west has been triggered by the mud eruption. A simple modeling suggests that 1) the conduit needs to be narrower at depth than at the surface, 2) the effective rigidity of the mud needs to be lower than that estimated from the drilled sample, or both to explain the observed decay constant of the deformation.

Aoki, Yosuke; Sidiq, Teguh Purnama

2014-05-01

39

Multispectral thermal infrared mapping of sulfur dioxide plumes: A case study from the East Rift Zone of Kilauea Volcano, Hawaii  

USGS Publications Warehouse

The synoptic perspective and rapid mode of data acquisition provided by remote sensing are well suited for the study of volcanic SO2 plumes. In this paper we describe a plume-mapping procedure that is based on image data acquired with NASA's airborne thermal infrared multispectral scanner (TIMS) and apply the procedure to TIMS data collected over the East Rift Zone of Kilauea Volcano, Hawaii, on September 30, 1988. These image data covered the Pu'u 'O'o and Kupaianaha vents and a skylight in the lava tube that was draining the Kupaianaha lava pond. Our estimate of the SO2 emission rate from Pu'u 'O'o (17 - 20 kg s-1) is roughly twice the average of estimates derived from correlation spectrometer (COSPEC) measurements collected 10 days prior to the TIMS overflight (10 kg s-1). The agreement between the TIMS and COSPEC results improves when we compare SO2 burden estimates, which are relatively independent of wind speed. We demonstrate the feasibility of mapping Pu'u 'O'o - scale SO2 plumes from space in anticipation of the 1998 launch of the advanced spaceborne thermal emission and reflectance radiometer (ASTER). Copyright 1997 by the American Geophysical Union.

Realmuto, V.J.; Sutton, A.J.; Elias, T.

1997-01-01

40

Preliminary Analytical Results for a Mud Sample Collected from the LUSI Mud Volcano, Sidoarjo, East Java, Indonesia  

USGS Publications Warehouse

On May 29, 2006, mud and gases began erupting unexpectedly from a vent 150 meters away from a hydrocarbon exploration well near Sidoarjo, East Java, Indonesia. The eruption, called the LUSI (Lumpur 'mud'-Sidoarjo) mud volcano, has continued since then at rates as high as 160,000 m3 per day. At the request of the United States Department of State, the U.S. Geological Survey (USGS) has been providing technical assistance to the Indonesian Government on the geological and geochemical aspects of the mud eruption. This report presents initial characterization results of a sample of the mud collected on September 22, 2007, as well as inerpretive findings based on the analytical results. The focus is on characteristics of the mud sample (including the solid and water components of the mud) that may be of potential environmental or human health concern. Characteristics that provide insights into the possible origins of the mud and its contained solids and waters have also been evaluated.

Plumlee, Geoffrey S.; Casadevall, Thomas J.; Wibowo, Handoko T.; Rosenbauer, Robert J.; Johnson, Craig A.; Breit, George N.; Lowers, Heather A.; Wolf, Ruth E.; Hageman, Philip L.; Goldstein, Harland L.; Anthony, Michael W.; Berry, Cyrus J.; Fey, David L.; Meeker, Gregory P.; Morman, Suzette A.

2008-01-01

41

REALTIME MONITORING OF ACTIVE VOLCANOES IN EAST ASIA USING MODIS AND MTSAT DATA AND ITS ADVANCEMENT BY GCOM-C1 SGLI  

E-print Network

Many active volcanoes are distributing in east Asia, however, most of them are not well monitored. Monitoring volcanoes is a key issue for disaster mitigation, as well as scientific studies. It is not realistic to install ground-based instruments to all of the active volcanoes, thus virtually satellite remote sensing is the only way to monitor them scattering in such wide areas. We developed a monitoring system based on Moderate Resolution Imaging Spectroradiometer (MODIS) and Multi-functional Transport Satellite (MTSAT) data, and are currently monitoring 147 active volcanoes in this area. The observation results are uploaded on the website in real or near-real time, after acquisition of observation data. Based on these data, we analyzed details of eruption processes occurred at Asama and Sarychev Peak in 2009, in conjunction with high resolutions images or ground-based observations. We plan to improve the current monitoring system utilizing the advanced observation capabilities of GCOM-C1 SGLI launching in 2014. The SGLI 1.6 ?m and 11 ?m channels have 250 m resolution, which is four times higher than that of 3.7 ?m and 11 ?m channels of MODIS. These high resolution channels enable to operate more sensitive thermal monitoring of volcanic activities. 1.

T. Kaneko A; A. Yasuda A; S. Kitagawa C

42

Puhimau thermal area: A window into the upper east rift zone of Ki??lauea Volcano, Hawaii?  

USGS Publications Warehouse

We report the results of two soil CO2 efflux surveys by the closed chamber circulation method at the Puhimau thermal area in the upper East Rift Zone (ERZ) of Ki??lauea volcano, Hawaii. The surveys were undertaken in 1996 and 1998 to constrain how much CO2 might be reaching the ERZ after degassing beneath the summit caldera and whether the Puhimau thermal area might be a significant contributor to the overall CO2 budget of Ki??lauea. The area was revisited in 2001 to determine the effects of surface disturbance on efflux values by the collar emplacement technique utilized in the earlier surveys. Utilizing a cutoff value of 50 g m-2 d-1 for the surrounding forest background efflux, the CO2 emission rates for the anomaly at Puhimau thermal area were 27 t d-1 in 1996 and 17 t d-1 in 1998. Water vapor was removed before analysis in all cases in order to obtain CO2 values on a dry air basis and mitigate the effect of water vapor dilution on the measurements. It is clear that Puhimau thermal area is not a significant contributor to Ki??lauea's CO2 output and that most of Ki??lauea's CO2 (8500 t d-1) is degassed at the summit, leaving only magma with its remaining stored volatiles, such as SO2, for injection down the ERZ. Because of the low CO2 emission rate and the presence of a shallow water table in the upper ERZ that effectively scrubs SO2 and other acid gases, Puhimau thermal area currently does not appear to be generally well suited for observing temporal changes in degassing at Ki??lauea. ?? Birkha??user Verlag, Basel, 2006.

McGee, K.A.; Sutton, A.J.; Elias, T.; Doukas, M.P.; Gerlach, T.M.

2006-01-01

43

Physical and acoustic properties of sediments off the coasts of Molokai and Lanai Islands, Hawaii  

E-print Network

Examination of physical and acoustic properties of carbonate-rich sediments was conducted on a suite of cores off of the coasts of Molokai and Lanai Islands, Hawaii. Carbonate mineralogy, grain size, grain density, porosity, bulk density...

Bayer, Mary Rose

2003-01-01

44

Increase in nitrate and chloride deposition in east Asia due to increased sulfate associated with the eruption of Miyakejima Volcano  

Microsoft Academic Search

The eruption of Miyakejima Volcano, 180 km south of Tokyo, Japan, since July 2000 has resulted in the emission of large amounts of sulfur dioxide. The volumes of sulfur dioxide emitted were vast, equivalent to half the anthropogenic emission from China on annual average. Short-time aerosol sampling, conducted at the Happo Ridge observatory in the central mountainous region of Japan,

Mizuo Kajino; Hiromasa Ueda; Hikaru Satsumabayashi; Zhiwei Han

2005-01-01

45

Temporal monitoring of radiative heat flux from the craters of Tendürek volcano (East Anatolia, Turkey) using ASTER satellite imagery  

NASA Astrophysics Data System (ADS)

Tendürek volcano is situated in the Eastern Anatolia near Turkish-Iranian border. It is one of the youngest volcanoes of Eastern Anatolia and it is a polygenetic, basaltic shield volcano formed by successive basalt flows. Tendürek is characterized by alkaline volcanism. Holocene and historical activity has been reported. Hydrothermal activity have been observed on the twin summit craters. Fumaroles, steam vents, steam/gas emission and zones of hot grounds have been reported. In order to quantify and to determine a base value for the current thermal state of the volcano, we used ASTER Thermal Infrared spectra. Four ASTER daytime and nighttime images have been used to calculate radiative heat flux from the craters. Heat flux calculations have been made using three nighttime images and a daytime image acquired in 2002, 2004, 2008 and 2012. Images have been atmospherically corrected, temperature and emissivity have been separated and Land Surface Temperature (LST) has been calculated from 5 thermal bands. LST images have been topographically corrected. Heat flux have been calculated using corrected surface temperature data, emissivity, vapor pressure and height-dependent air temperature values. Maximum temperature anomalies observed were 9.0 °C and 15.9 °C for the western and eastern craters respectively. Heat flux is estimated between 14.4 and 25.2 W/m² at the western crater and between 16.5 and 49.4 W/m² at the eastern crater. These values are well correlated with other known low-level activity volcanoes such as Yellowstone, Stromboli and Nisyros, whereas they are lower than that of observed at Vulcano.

Ulusoy, ?nan

2014-05-01

46

Variations in tilt rate and harmonic tremor amplitude during the January-August 1983 east rift eruptions of Kilauea Volcano, Hawaii  

USGS Publications Warehouse

During January-August 1983, a network of telemetered tiltmeters and seismometers recorded detailed temporal changes associated with seven major eruptive phases along the east rift of Kilauea Volcano, Hawaii. Each eruptive phase was accompanied by subsidence of the summit region and followed by reinflation of the summit to approximately the same level before renewal of eruptive activity. The cyclic summit tilt pattern and the absence of measurable tilt changes near the eruptive site suggest that conditions in the summit region controlled the timing of the last six eruptive phases. The rate of summit subsidence progressively increased from one eruptive phase to the next during the last six phases; the amplitude of harmonic tremor increased during the last four phases. The increases in subsidence rate and in tremor amplitude suggest that frequent periods of magma movement have reduced the flow resistance of the conduit system between the summit and the rift zone. ?? 1985.

Dvorak, J.J.; Okamura, A.T.

1985-01-01

47

Nicaraguan Volcanoes  

Atmospheric Science Data Center

article title:  Nicaraguan Volcanoes     View Larger Image Nicaraguan volcanoes, February 26, 2000 . The true-color image at left is a ... February 26, 2000 - Plumes from the San Cristobal and Masaya volcanoes. project:  MISR category:  gallery ...

2013-04-18

48

Extreme alteration by hyperacidic brines at Kawah Ijen volcano, East Java, Indonesia: I. Textural and mineralogical imprint  

NASA Astrophysics Data System (ADS)

Kawah Ijen volcano, located on the eastern tip of Java and renowned for its large hyperacidic crater lake, poses significant volcanic and environmental hazards to its immediate surroundings. Crater lake brines seep through the flanks of the volcano to form the Banyu Pahit river, which is used in irrigation downstream, resulting in extensive pollution, sharply reduced crop yields and health problems. The impact on the environment comes mainly from the high element load, which is derived from leaching of rocks by the acid fluids and transported downstream. Our detailed study of water-rock interaction in different parts of the Kawah Ijen system indicates that there are three settings for this alteration; the crater lake and Banyu Pahit riverbed, the hydrothermal system below the lake, and the solfatara of the active rhyolite dome. In all three settings, the silicates are leached and altered to amorphous silica in the order olivine + glass > An-rich plagioclase > ortho-pyroxene > clino-pyroxene > Ab-rich plagioclase. In contrast, the alteration of titanomagnetite is characterised by dissolution in the surficial setting, replacement by pyrite and Ti-oxide in the hydrothermal system and pyritisation + Ti-mobility in the fumarole conduits. Alteration progresses along crystallographically controlled planes in all phases, and shows strong compositional control in plagioclase and titanomagnetite. No secondary minerals develop, except for minor barite, cristobalite, pyrite and jarosite. This indicates that, despite its high element load, the waters are undersaturated with respect to most secondary minerals typically produced during alteration of these magmatic rocks by acid chloride-sulphate brines, and that water-rock interaction at Kawah Ijen is not a sink of elements, but rather contributes to the element load transported downstream.

van Hinsberg, Vincent; Berlo, Kim; van Bergen, Manfred; Williams-Jones, Anthony

2010-12-01

49

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

50

Earth's Active Volcanoes by Geographic Region  

NSDL National Science Digital Library

This site describes active volcanoes from around the world by using the volcano links from the Michigan Technological University and the homepages of observatories at active volcanoes. Each volcano section contains photo images, maps, and reference text. Some sections contain bibliographies, volcano reports, and video clips of lahars. The volcanoes are organized by the following geographic regions: Africa and surrounding islands; the Southwest Pacific, Southeast Asia, and India; East Asia including Japan and Kamchatka; Antarctica; the North Atlantic and Iceland; the Mediterranean; South America and surrounding islands; Central Pacific, South Pacific and New Zealand; Alaska and the Northern Pacific Region; North America; and Central America.

51

Seismic reflection study of acoustic basement in the South Korea Plateau, the Ulleung Interplain Gap, and the northern Ulleung Basin: Volcano-tectonic implications for Tertiary back-arc evolution in the southern East Sea  

Microsoft Academic Search

In order to understand the volcano-tectonic evolution history of the East Sea back-arc basin, this study focuses on the seismic characteristics of acoustic basement, based on the multi-channel seismic reflection data acquired from the South Korea Plateau, the northern Ulleung Basin, and the Ulleung Interplain Gap. According to the seismic reflection characteristics, the “acoustic basement” in the study area can

G. B. Kim; S. H. Yoon; S. K. Chough; Y. K. Kwon; B. J. Ryu

2011-01-01

52

Nematode Assemblages in Native Plant Communities of Molokai, Hawaii  

PubMed Central

Four native plant community types (in decreasing elevation: montane bog, rain forest, wet mesic forest, drier forest) on Molokai were sampled for nematodes. Six samples of 10 cores each were gathered from each community. Nematodes were extracted from 200 cm³ soil by elutriation. All extracted nematodes were counted and identified to species-level taxa. Sixty-seven species were identified among the four plant communities; only eight species occurred in all four communities. Species diversity and evenness were greater in the rain forest and mesic forest than in the bog and the drier forest, but the drier forest and mesic forest had similar species communities. The bog nematode community was not similar to the other three sites. In a presence/absence cluster analysis, all six bog sample assemblages clustered together. The rain forest samples also clustered together but were associated with the mesic forest sample closest to the rain forest edge. Of 11 nematode orders collected, Tylenchida accounted for 40% to 73% of all individuals, followed by Dorylaimida (5% to 17%). Diplogasterida were absent. No plant-parasitic nematodes of known Hawaiian agricultural importance or occurrence were collected in these native plant communities. Calculated nematode densities (76,000 to 321,300/m²) were comparable to those reported for some other Pacific tropical forests. PMID:19262867

Bernard, E. C.; Schmitt, D. P.

2005-01-01

53

Perspective View, Radar Image, Color as Height, Molokai, Lanai and Maui, Hawaii  

NASA Technical Reports Server (NTRS)

This perspective view shows three Hawaiian islands: Molokai (lower left), Lanai (right), and the northwest tip of Maui (upper left). Data such as these will be useful for studying the history of volcanic activity on these now extinct volcanoes. SRTM data also will help local officials evaluate and mitigate natural hazards for islands throughout the Pacific. For example, improved elevation data will make it easier for communities to plan for tsunamis (tidal waves generated by earthquakes around the perimeter of the Pacific) by helping them identify evacuation routes and areas prone to flooding.

This perspective view combines two types of data from the Shuttle Radar Topography Mission. The image brightness corresponds to the strength of the radar signal reflected from the ground, while colors show the elevation as measured by SRTM. Colors range from blue at the lowest elevations to white at the highest elevations. This image contains 1800 meters (5900 feet) of total relief.

The Shuttle Radar Topography Mission (SRTM), launched on February 11,2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) and the German (DLR) and Italian (ASI) space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise,Washington, DC.

Size: 60 by 70 kilometers (37 by 43 miles) Location: 20.8 deg. North lat., 156.7 deg. West lon. Orientation: Looking southeast Original Data Resolution: 30 meters (99 feet) Date Acquired: February 18, 2000

2000-01-01

54

A Practical Framework for Evaluating a Culturally Tailored Adolescent Substance Abuse Treatment Programme in Molokai, Hawaii  

Microsoft Academic Search

Objective. Successful substance abuse treatment requires many changes in behavior, attitude and skills. Culturally tailored approaches to substance abuse treatment have shown initial success, but are not yet accepted as best practice models. In order to document programme effectiveness of a new culturally tailored substance abuse treatment programme on the rural island of Molokai, Hawaii, the authors worked to develop

Kelley M. Withy; Wayde Lee; Ralph F. Renger

2007-01-01

55

Decade Volcanoes  

NSDL National Science Digital Library

In the 1990s, the International Association of Volcanology and Chemistry of the Earth's Interior started the Decade Volcano Project. As part of their work, they designated sixteen volcanoes particularly worthy of study "because of their explosive histories and close proximity to human populations." The group recently teamed up with National Geographic to create a guide to these volcanoes via this interactive map. Navigating through the map, visitors can learn about Mount Rainier, Colima, Galeras, Santorini, and other prominent volcanoes. For each volcano, there's a brief sketch that gives the date of its last eruption, its elevation, nearby population centers, and a photograph.

56

Anomalously high b-values in the South Flank of Kilauea volcano, Hawaii: Evidence for the distribution of magma below Kilauea's East rift zone  

USGS Publications Warehouse

The pattern of b-value of the frequency-magnitude relation, or mean magnitude, varies little in the Kaoiki-Hilea area of Hawaii, and the b-values are normal, with b = 0.8 in the top 10 km and somewhat lower values below that depth. We interpret the Kaoiki-Hilea area as relatively stable, normal Hawaiian crust. In contrast, the b-values beneath Kilauea's South Flank are anomalously high (b = 1.3-1.7) at depths between 4 and 8 km, with the highest values near the East Rift zone, but extending 5-8 km away from the rift. Also, the anomalously high b-values vary along strike, parallel to the rift zone. The highest b-values are observed near Hiiaka and Pauahi craters at the bend in the rift, the next highest are near Makaopuhi and also near Puu Kaliu. The mildest anomalies occur adjacent to the central section of the rift. The locations of the three major and two minor b-value anomalies correspond to places where shallow magma reservoirs have been proposed based on analyses of seismicity, geodetic data and differentiated lava chemistry. The existence of the magma reservoirs is also supported by magnetic anomalies, which may be areas of dike concentration, and self-potential anomalies, which are areas of thermal upwelling above a hot source. The simplest explanation of these anomalously high b-values is that they are due to the presence of active magma bodies beneath the East Rift zone at depths down to 8 km. In other volcanoes, anomalously high b-values correlate with volumes adjacent to active magma chambers. This supports a model of a magma body beneath the East Rift zone, which may widen and thin along strike, and which may reach 8 km depth and extend from Kilauea's summit to a distance of at least 40 km down rift. The anomalously high b-values at the center of the South Flank, several kilometers away from the rift, may be explained by unusually high pore pressure throughout the South Flank, or by anomalously strong heterogeneity due to extensive cracking, or by both phenomena. The major b-value anomalies are located SSE of their parent reservoirs, in the direction of motion of the flank, suggesting that magma reservoirs leave an imprint in the mobile flank. We hypothesize that the extensive cracking may have been acquired when the anomalous parts of the South Flank, now several kilometers distant from the rift zone, were generated at the rift zone near persistent reservoirs. Since their generation, these volumes may have moved seaward, away from the rift, but earthquakes occurring in them still use the preexisting complex crack distribution. Along the decollement plane at 10 km depth, the b-values are exceptionally low (b = 0.5), suggesting faulting in a more homogeneous medium. ?? 2001 Elsevier Science B.V. All rights reserved.

Wyss, M.; Klein, F.; Nagamine, K.; Wiemer, S.

2001-01-01

57

Volcano Hazards Assessment for Medicine Lake Volcano, Northern California  

USGS Publications Warehouse

Medicine Lake volcano (MLV) is a very large shield-shaped volcano located in northern California where it forms part of the southern Cascade Range of volcanoes. 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 volcanoes 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 volcano indicates that once it becomes active, the volcano 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 volcano' by the U.S. Geological Survey (USGS) National Volcano Early Warning System assessment. Volcanic eruptions are typically preceded by seismic activity, but with only two seismometers located high on the volcano and no other USGS monitoring equipment in place, MLV is at present among the most poorly monitored Cascade volcanoes.

Donnelly-Nolan, Julie M.; Nathenson, Manuel; Champion, Duane E.; Ramsey, David W.; Lowenstern, Jacob B.; Ewert, John W.

2007-01-01

58

Volcano Vents  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

Released 5 May 2003

This low-relief shield volcano 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.

Image information: VIS instrument. Latitude 17.6, Longitude 243.6 East (116.4 West). 19 meter/pixel resolution.

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.

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.

2003-01-01

59

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.

60

Redoubt Volcano  

USGS Multimedia Gallery

Ascending eruption cloud from Redoubt Volcano as viewed to the west from the Kenai Peninsula. The mushroom-shaped plume rose from avalanches of hot debris (pyroclastic flows) that cascaded down the north flank of the volcano. A smaller, white steam plume rises from the summit crater. ...

61

Cascade Volcanoes  

USGS Multimedia Gallery

The volcanoes 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....

62

Volcano Preparedness  

MedlinePLUS

... Safety Hurricane Landslide Pet Safety Poisoning Power Outage Terrorism Thunderstorm Tornado Tsunami Volcano Water Safety Wildfire Winter ... all windows, doors, and dampers. Put all machinery inside a garage or barn. Bring animals and livestock ...

63

Seismic reflection study of acoustic basement in the South Korea Plateau, the Ulleung Interplain Gap, and the northern Ulleung Basin: Volcano-tectonic implications for Tertiary back-arc evolution in the southern East Sea  

NASA Astrophysics Data System (ADS)

In order to understand the volcano-tectonic evolution history of the East Sea back-arc basin, this study focuses on the seismic characteristics of acoustic basement, based on the multi-channel seismic reflection data acquired from the South Korea Plateau, the northern Ulleung Basin, and the Ulleung Interplain Gap. According to the seismic reflection characteristics, the "acoustic basement" in the study area can be classified into three types. Type-A acoustic basement is a remnant of rifted continental crust comprising relatively shallow-seated continental margin platforms, elongated ridges, and equidimensional blocks in the South Korea Plateau and its vicinities. Type-B acoustic basement is volcanic sills/flows-sediments complexes infilling the rift-controlled basement lows in the South Korea Plateau, the Ulleung Interplain Gap, and the northern Ulleung Basin. Type-C acoustic basement is a cluster or chain of volcanic edifices which shows internal facies variation from main body to apron slope facies. Volcanic activities identified in the types-B and -C acoustic basements can be classified into three stages based on the volcano-stratigraphic correlation with the existing stratigraphic framework. Stage-1 volcanism is characterized by a fissure-type eruption represented by scattering volcanic cones and mounds (type-C), and volcanic sills and lava flows interlayering with syn-rift sedimentary units (type-B). Early-stage continental rifting prior to the Middle Miocene most likely controlled this volcanism. Stage-2 volcanism is characterized by ENE-WSW trending chain of volcanic edifices (type-C) along the northern margin of the Ulleung Basin and Ulleung Interplain Gap. During the Middle Miocene, the weakening of back-arc extension might have resulted in limited volcanic eruption, which formed elongate volcanic fields across the Ulleung and Yamato basins. Stage-3 volcanism is represented by highly peaked volcanic islands and seamounts (type-C) showing vertically stacked apron slopes in seismic cross-sections. This vertical stacking pattern is indicative of multiple eruption events from a single eruption center at least from the Late Miocene to the Quaternary. Expanded volcanic age-control, based on volcano-stratigraphic and isotopic age dating, reveals that the volcanic activities in the southwestern and southeastern East Sea show similar spatio-temporal variations. This implies that the entire southern East Sea has experienced almost same volcano-tectonic evolution during the Cenozoic back-arc evolution. Especially, the stage-2 volcanic chain along the northern Ulleung Basin and the Yamato Seamount Chain in the Yamato Basin matches in their eruption timing (ca. 12 Ma) and geomorphic properties (i.e., direction of the volcanic chains and distances from subduction zone), which strongly suggests the existence of regional-scale chain volcanism across the southern East Sea. Considering the chemical properties of volcanic rock samples from the volcanic chain in association with the suggested tectonic frameworks during the Tertiary, the remnant magma source derived from the waning mantle convection most likely fed the volcanic chain in the terminal stage of back-arc opening.

Kim, G. B.; Yoon, S. H.; Chough, S. K.; Kwon, Y. K.; Ryu, B. J.

2011-05-01

64

Volcano Baseball  

NSDL National Science Digital Library

In this game, learners are volcanoes 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 volcano's eruption. The first learner to make it back to home plate erupts and is the winner. This is a good introduction to volcanoes. 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.

Science, American A.

2009-01-01

65

Ultrastructure and potential sub-seafloor evidence of bacteriogenic iron oxides from Axial Volcano, Juan de Fuca Ridge, north-east Pacific Ocean.  

PubMed

Iron oxides from the caldera of Axial Volcano, a site of hydrothermal vent activity along the Juan de Fuca Ridge, were found to consist predominantly of microbial structures in hydrated whole mounts examined using an environmental scanning electron microscope. Novel observations were made of the iron oxides revealing the spatial relationships of the bacteria within to be more consistent with microbial mats than mineral precipitates. The bacterial structures are attributed to the sheaths of Leptothrix ochracea, the stalks of Gallionella ferruginea, and the filaments of a novel iron oxidizing PV-1 strain, based on the distinctive morphological characteristics of these three bacteria. Energy dispersive X-ray spectroscopy revealed the presence and distribution of Fe, Si, and Cl on the bacterial sheaths, stalks and filaments. The iron oxides were identified by X-ray diffraction to be two-line ferrihydrite, a poorly ordered iron oxyhydroxide. Adsorption of Si in particular to two-line ferrihydrite likely contributes to its stability on the seafloor, and might also be a preservation mechanism creating microfossils of the bacterial structures encrusted with ferrihydrite. Presumptive evidence of the sub-seafloor presence of L. ochracea, G. ferruginea and PV-1 at Axial Volcano was obtained from the presence of these bacteria on a trap that had been placed within an active vent, and also in a vent fluid sample. If indeed these bacteria are present in the sub-seafloor, it may be an indication that the surface expression of iron oxide deposits at Axial Volcano is minimal in comparison to what exists beneath the seafloor. PMID:19719685

Kennedy, C B; Scott, S D; Ferris, F G

2003-03-01

66

Comparative study of lahars generated by the 1961 and 1971 eruptions of Calbuco and Villarrica volcanoes, Southern Andes of Chile  

Microsoft Academic Search

The Villarrica and Calbuco volcanoes, of the Andean Southern Volcanic Zone, are two of the most active volcanoes in Chile and have erupted several times in the XX century. The 1961 eruption at Calbuco volcano generated lahars on the North, East and Southern flanks, while the 1971 eruption at Villarrica volcano generated lahars in almost all the drainages towards the

Angelo Castruccio; Jorge Clavero; Andrés Rivera

2010-01-01

67

Klyuchevskaya Volcano  

NASA Technical Reports Server (NTRS)

The Klyuchevskaya Volcano on Russia's Kamchatka Peninsula continued its ongoing activity by releasing another plume on May 24, 2007. The same day, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured this image, at 01:00 UTC. In this image, a hotspot marks the volcano's summit. Outlined in red, the hotspot indicates where MODIS detected unusually warm surface temperatures. Blowing southward from the summit is the plume, which casts its shadow on the clouds below. Near the summit, the plume appears gray, and it lightens toward the south. With an altitude of 4,835 meters (15,863 feet), Klyuchevskaya (sometimes spelled Klyuchevskoy or Kliuchevskoi) is both the highest and most active volcano on the Kamchatka Peninsula. As part of the Pacific 'Ring of Fire,' the peninsula experiences regular seismic activity as the Pacific Plate slides below other tectonic plates in the Earth's crust. Klyuchevskaya is estimated to have experienced more than 100 flank eruptions in the past 3,000 years. Since its formation 6,000 years ago, the volcano has seen few periods of inactivity. NASA image courtesy the MODIS Rapid Response Team at NASA GSFC. The Rapid Response Team provides daily images of this region.

2007-01-01

68

Iceland Volcano  

Atmospheric Science Data Center

... of which are so thick that they block the penetration of light from CALIPSO's lidar to the surface. The yellow layer near the surface over France is believed to be primarily air pollution, but could also contain ash from the volcano. Highlighting its ...

2013-04-23

69

An autogamous rainforest species of Schiedea (Caryophyllaceae) from East Maui, Hawaiian Islands  

USGS Publications Warehouse

A new autogamous species of Schiedea is described and illustrated. It is known only from cliff habitat in rainforest on a single ridge in the Natural Area Reserve, Hanawi, East Maui. With the addition of this species there are 28 species in this endemic Hawaiian genus. The new species appears to be most closely related to Schiedea nuttallii, a species of mesic habitats on O'ahu, Moloka'i, and Maui.

Wagner, W.L.; Weller, S.G.; Sakai, A.K.; Medeiros, A.C.

1999-01-01

70

Scoping Meeting Summary, Kaunakakai, Moloka'i, March 12, 1992, 2 PM Session  

SciTech Connect

The meeting began with presentations by the facilitator, Mr. Spiegel, and Dr. Lewis, the program manager from DOE. The facilitator introduced those on the podium. He then described the general structure of the meeting and its purpose: to hear the issues and concerns of those present regarding the proposed Hawaiian Geothermal Project. He described his role as assuring the impartiality and fairness of the meeting. Dr. Lewis of DOE further defined the scope of the project, introduced members of the EIS team, and briefly described.the EIS process. The overwhelming concerns of the meeting were Native Hawaiian issues. The presenters [more than 70%, most of whom addressed no other issue] want the EIS to respect Native Hawaiian religion, race, rights, language, and culture, noting that they believe that geothermal development is a desecration of Pele [{approx}60% of all presenters]. They expressed concern that their ancestors and burials should not be desecrated. The EIS should address Native Hawaiian concerns that the HGP would negatively impact Native Hawaiian fisheries, subsistence lifestyles, and religious practices. Virtually all the speakers expressed frustration with government. Most (> 70%) of the speakers voiced concern and frustration regarding lack of consideration for Native Hawaiians by government and lack of trust in government. One commenter requested that the EIS should consider the international implications of the U.S allowing their rainforests to be cleared, when the U.S. government asks other nations to preserve theirs. Nearly 30% of the commenters want the EIS to address the concern that people on Moloka'i will bear major environmental consequences of the HGP, but not gain from it. The commenters question whether it is right for Moloka'i to pay for benefits to Oahu, particularly using an unproven technology. After questioning the reliability and feasibility of the marine cable:, nearly 30% of the presenters were concerned about the impacts of the submarine cable. In specific, they suggested that the EIS investigate the impacts the cable would have on fisheries and marine life due to electromagnetic fields, dredging, and oil-release. The EIS should study the impacts of the HGP on the humpback whale and other marine species, particularly their birthing grounds, noting whales' hypersensitivity to emf and sound. One commenter suggested that the EIS examine the economics of the cable, including the need to build specialized ships to lay it, harbour(s), and the cable itself. One commenter was concerned about the future uses of the cable suggesting that the EIS should address the impacts that would result if the cable connecting Moloka'i to Oahu is used to transmit power from large coal or other types of power generation facilities constructed on Moloka'i. Commenters questioned the reliability of geothermal development in a region that is both seismically and volcanically active. One suggested that the EIS examine the merits of projects that conserve energy. With respect to land use, commenters asked that the EIS examine the propriety of using Native Hawaiian homelands and ceded lands for the HGP, questioning specifically the land exchange in Puna [Campbell Estate for Wao Kele o Puna]. The commenters want the EIS to address the issue of air, water and sail quality preservation. More than 20% of the commenters asked that the EIS examine concerns about the environmental consequences of the HGP to the rainforest, including possible species extinction. In particular, the EIS should address the impacts of roads associated with the HGP in the rainforest, including the resulting importation of exotic species (for example banana poko), which successfully compete against native species; and the effects of noise and fumes which negatively impact plants, birds, animals, and insects.

Quinby-Hunt, Mary S.

1992-06-01

71

Coral proxy record of decadal-scale reduction in base flow from Moloka'i, Hawaii  

USGS Publications Warehouse

Groundwater is a major resource in Hawaii and is the principal source of water for municipal, agricultural, and industrial use. With a growing population, a long-term downward trend in rainfall, and the need for proper groundwater management, a better understanding of the hydroclimatological system is essential. Proxy records from corals can supplement long-term observational networks, offering an accessible source of hydrologie and climate information. To develop a qualitative proxy for historic groundwater discharge to coastal waters, a suite of rare earth elements and yttrium (REYs) were analyzed from coral cores collected along the south shore of Moloka'i, Hawaii. The coral REY to calcium (Ca) ratios were evaluated against hydrological parameters, yielding the strongest relationship to base flow. Dissolution of REYs from labradorite and olivine in the basaltic rock aquifers is likely the primary source of coastal ocean REYs. There was a statistically significant downward trend (-40%) in subannually resolved REY/Ca ratios over the last century. This is consistent with long-term records of stream discharge from Moloka'i, which imply a downward trend in base flow since 1913. A decrease in base flow is observed statewide, consistent with the long-term downward trend in annual rainfall over much of the state. With greater demands on freshwater resources, it is appropriate for withdrawal scenarios to consider long-term trends and short-term climate variability. It is possible that coral paleohydrological records can be used to conduct model-data comparisons in groundwater flow models used to simulate changes in groundwater level and coastal discharge. Copyright 2009 by the American Geophysical Union.

Prouty, N.G.; Jupiter, S.D.; Field, M.E.; McCulloch, M.T.

2009-01-01

72

Volcano-tectonics at Tharsis Tholus, Mars: Observation and Experiments  

Microsoft Academic Search

Tharsis Tholus, located to the east of the three Tharsis Montes, is a large volcano partly buried beneath volcaniclastic material. The visible edifice has a planar extent of about 155 km (NW-SE) by 125 km (NE-SW), and displays large fault scarps and a central caldera. The fault traces are extending radially from the centre of the volcano and deeply breach

Thomas Platz; Sebastian Münn; Thomas Walter

2010-01-01

73

New volcano newsletter planned  

NASA Astrophysics Data System (ADS)

In the beginning, there was Volcano News, an interdisciplinary forum where volcanophiles of all stripes—4professional and amateur, “hard” and “soft” scientists alike— could exchange information. Unfortunately, Volcano News became extinct when editor-publisher Chuck Wood became involved in editing Volcanoes of North America. Janet Cullen Tanaka, a former contributing associate editor of Volcano News is planning the publication of a new interdisciplinary volcano newsletter to cover all facets of volcano studies, from geophysics to emergency management.

74

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

75

Distribution of differentiated tholeiitic basalts on the lower east rift zone of Kilauea Volcano, Hawaii: a possible guide to geothermal exploration.  

USGS Publications Warehouse

Geological mapping of the lower east rift zone indicates that >100 eruptions have extruded an estimated 10 km3 of basalt during the past 2000 yr; six eruptions in the past 200 yr have extruded approx 1 km3. The eruptive recurrence interval has ranged 1-115 yr since the middle of the 18th century and has averaged 20 yr or less over the past 2000 yr. New chemical analyses (100) indicate that the tholeiites erupted commonly differentiated beyond olivine control or are hybrid mixtures of differentiates with more mafic (olivine-controlled) summit magmas. The distribution of vents for differentiated lavas suggests that several large magma chambers underlie the lower east rift zone. Several workers have recognized that a chamber underlies the area near a producing geothermal well, HGP-A; petrological and 14C data indicate that it has existed for at least 1300 yr. Stratigraphy, petrology and surface-deformation patterns suggest that two other areas, Heiheiahulu and Kaliu, also overlie magma chambers and show favourable geothermal prospects.-A.P.

Moore, R.B.

1983-01-01

76

Seismic reflection study in the South Korea Plateau, the Ulleung Interplain Gap, and the northern Ulleung Basin: volcano-tectonic implications for Tertiary back-arc evolution in the southern East Sea  

NASA Astrophysics Data System (ADS)

Multi-channel seismic reflection data, acquired from the mid-western part of the East Sea, provide evidences for the nature of acoustic basement and overlying sedimentary succession. In the study area, the acoustic basement can be classified into three types, and the sedimentary succession into four seismic units. Type-A acoustic basement is a remnant of rifted continental crust comprising relatively shallow-seated continental crustal blocks. Type-B acoustic basement is syn-rift volcanic sills/flows-sediments complexes infilling the rift-controlled basement lows. Type-C acoustic basement is a cluster or chain of volcanic edifices. Sedimentary unit-1 is characterized by short and irregular high-amplitude reflectors and interpreted as a syn-rift deposit consisting of non-marine volcanics/sediment complex in topographic lows. Sedimentary unit-2 and -3 formed in an open marine environment during the Middle Miocene to Early Pliocene, characterized by onlap-fill and later draping marine sedimentary succession dominantly composed of hemipelagic sediments and turbidites with frequent intercalation of mass-flow deposits. Along the western margin of the plateau, these units were deformed under a compressional regime in the Early Pliocene, associated with the back-arc closing pahse. Sedimentary unit-4 (deposited since the Early Pliocene) comprises hemipelagic sediments and turbidites with evidence of sporadic slides/slumps. Among the three types of acoustic basement, type-B and -C are closely related to volcanic activities, which can be classified into three stages. Stage-1 volcanism is characterized by a fissure-type eruption represented by scattering volcanic cones and mounds (type-C), and volcanic sills and lava flows interlayering with syn-rift sedimentary units (unit-1; type-B). Stage-2 volcanism is characterized by ENE-WSW trending chain of volcanic edifices (type-C) along the northern margin of the Ulleung Basin and Ulleung Interplain Gap. Stage-3 volcanism is represented by highly peaked volcanic islands and seamounts (type-C) showing vertically stacked apron slopes in seismic cross-sections. Expanded volcanic age-control, based on volcano-stratigraphic and isotopic age dating, reveals that volcanic activities in both the southwestern and southeastern East Sea have similar spatio-temporal variations. Especially, the stage-2 chain volcanism along the northern Ulleung Basin and the Yamato Seamount Chain in the Yamato Basin matches in their eruption timing and geomorphic properties (i.e., direction of the volcanic chains and distances from subduction zone), which strongly suggests the existence of regional-scale chain volcanism across the southern East Sea.

Kim, G.; Yoon, S.; Chough, S.; Kwon, Y.; Ryu, B.

2010-12-01

77

Volcano Lovers  

NSDL National Science Digital Library

This Why Files article explores volcanoes and volcanic eruptions. Topics covered include: Alaska's Pavlof and its threat to jet engines; Mexico City's restless neighbor, Popocatepetl (El Popo); underground volcanic processes; modern forecasting of eruptions; various volcanic phenomena and features; large flood basalt areas around the world; California's volcanically active area, Long Valley Caldera and Mammoth Mountain; Indonesia's Krakatau eruption in 1883, which was the world's largest historical eruption; Krakatau's ecological contribution to the study of colonization of sterile lands; and central Mexico's Paricutin which was witnessed emerging from a farmer's field in 1943. Three scientists were interviewed for this article.

Tenenbaum, David

1997-01-02

78

Nyiragonga Volcano  

NASA Technical Reports Server (NTRS)

This image of the Nyiragonga volcano 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.

Image: A river of molten rock poured from the Nyiragongo volcano 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 volcano'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 volcanoes, 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.

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.

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 volcanoes; 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.

2001-01-01

79

Structural setting of gold deposits in the Oudalan-Gorouol volcano-sedimentary belt east of the Markoye Shear Zone, West African Craton  

NASA Astrophysics Data System (ADS)

The Oudalan-Gorouol volcano-sedimentary belt (OGB) of Burkina Faso and Niger hosts meta-volcanic and metasedimentary sequences of the Birimian Supergroup that were folded and deformed during emplacement of the Dori Batholith (D1-x), the Tangaean Event (D1) and the Eburnean Orogeny (D2). The emplacement of the Dori Batholith accompanied aureole deformation (D1-x) and the development of proto-mylonite, migmatite, gneiss and schist on the northern margin of the batholith. Contact metamorphic grade reached granulite facies with partial melting of the supracrustal sequences. Emplacement of the Dori Batholith was succeeded by emplacement of monzonite dykes and sills through the OGB. The Tangaean Event (D1) accompanied formation of (a) the Saoga Branch of the Markoye Shear Zone (MSZ), (b) the Mukosi and Billiata mylonite zones that are hosted in the MSZ, (c) the Afu Branch of the Kargouna Shear Zone Complex (KSZC), and (d) northwest-trending thrust-folds (F1) that crosscut the OGB and coalesce with the MSZ. Metamorphic grade attained amphibolite facies in mylonite or proto-mylonite zones in the Saoga and Afu branches. D1 was succeeded by emplacement of alkali-granite plutons of the Dolbel Batholith. The Eburnean Orogeny, D2, accompanied formation of (a) the Korizéna Branch of the MSZ, (b) the Waho Branch of the KSZC, and (c) northeast-trending shear-faults that crosscut the OGB. D2 is manifested by refolding of F1 by northeast-trending F2, and development of a pervasive northeast-trending S2 to S2-C. Metamorphic grade attained greenschist facies during D2 with development of the mineral assemblage quartz-chlorite-muscovite ± actinolite. D2 was succeeded by emplacement of northwest-trending gabbro and dolerite dykes. The OGB hosts structurally-controlled gold deposits that are sited along five metallogenic corridors and include the Essakane, Tin-Fal, Bom Kodjelé, Kossa and Tassiri Trends. Gold mineralisation is preferentially located where northeast-trending faults and shears crosscut northwest-trending thrust-folds, or where northwest-trending thrust-folds coalesce with north-northeast trending shears. An intimate relationship thus exists between D1 and D2 structures and gold mineralisation in the OGB. Gold in sheeted-stockwork veins is hosted in competent rocks units including conglomerate beds, greywacke, quartzite, monzonite dykes, pyroxenite-gabbro sills and D1 buck quartz veins. Gold in fine veinlets may also be hosted in massive shale units.

Tshibubudze, Asinne; Hein, Kim A. A.

2013-04-01

80

Geologic map of Medicine Lake volcano, northern California  

USGS Publications Warehouse

Medicine Lake volcano forms a broad, seemingly nondescript highland, as viewed from any angle on the ground. Seen from an airplane, however, treeless lava flows are scattered across the surface of this potentially active volcanic edifice. Lavas of Medicine Lake volcano, which range in composition from basalt through rhyolite, cover more than 2,000 km2 east of the main axis of the Cascade Range in northern California. Across the Cascade Range axis to the west-southwest is Mount Shasta, its towering volcanic neighbor, whose stratocone shape contrasts with the broad shield shape of Medicine Lake volcano. Hidden in the center of Medicine Lake volcano is a 7 km by 12 km summit caldera in which nestles its namesake, Medicine Lake. The flanks of Medicine Lake volcano, which are dotted with cinder cones, slope gently upward to the caldera rim, which reaches an elevation of nearly 8,000 ft (2,440 m). The maximum extent of lavas from this half-million-year-old volcano is about 80 km north-south by 45 km east-west. In postglacial time, 17 eruptions have added approximately 7.5 km3 to its total estimated volume of 600 km3, and it is considered to be the largest by volume among volcanoes of the Cascades arc. The volcano has erupted nine times in the past 5,200 years, a rate more frequent than has been documented at all other Cascades arc volcanoes except Mount St. Helens.

Donnelly-Nolan, Julie M.

2011-01-01

81

In-situ Ar isotope, 40Ar/39Ar analysis and mineral chemistry of nosean in the phonolite from Olbrück volcano, East Eifel volcanic field, Germany: Implication for the source of excess 40Ar  

NASA Astrophysics Data System (ADS)

Since the report by Lippolt et al. (1990), hauyne and nosean phenocrysts in certain phonolites from the northwest in the Quaternary East Eifel volcanic field in Germany were known to contain significant amounts of excess 40Ar, thus, show apparent older ages than the other minerals. However, its petrographic meaning have not been well known. Meanwhile, Sumino et al. (2008) has identified the source of the excess 40Ar in the plagioclase phenocrysts from the historic Unzen dacite lava as the melt inclusions in the zones parallely developed to the plagioclase rim by in-situ laser Ar isotope analysis. In order to obtain eruption ages of very young volcanoes as like Quaternary Eifel volcanic field by the K-Ar system, it is quite essential to know about the location of excess 40Ar in volcanic rocks. We have collected phonolites from the Olbrück volcano in East Eifel and investigated its petrography and mineral chemistry and also performed in-situ Ar isotope analyses of unirradiated rock section sample and also in-situ 40Ar/39Ar analysis of neutron irradiated section sample with the UV pulse laser (wavelength 266 nm) and 40Ar/39Ar analytical system of the University of Potsdam. Petrographically, nosean contained fine melt and/or gas inclusions of less than 5 micrometer, which mostly distribute linearly and are relatively enriched in chlorine than the areas without inclusions. Solid inclusions of similar sizes contain CaO and fluorine. In nosean, typically around 5 wt% of sulfur is contained. The 40Ar/39Ar dating was also performed to leucite, sanidine and groundmass in the same section for comparison of those ages with that of nosean. In each analysis, 200 micrometer of beam size was used for making a pit with depth of up to 300 micrometer by laser ablation. As our 40Ar/39Ar analyses were conducted one and half year after the neutron irradiation, thus, short lived 37Ar derived from Ca had decayed very much, we measured Ca and K contents in nosean by SEM-EDS then applied their Ca/K ratios to the Ar analytical results. The in-situ Ar isotopic analysis of nosean and leucite show clearly the different slope of isochron and implied apparent older age for the nosean. The in-situ 40Ar/39Ar analysis of nosean yields three various ages, from 6.86 ± 2.77 Ma to 41.57 ± 11.58 Ma, but clearly older than those of the other minerals and groundmass. However, it was difficult to analyze and compare the 40Ar/39Ar ages between different areas with or without inclusions by the UV-laser because of its less spatial resolution, therefore, was difficult to understand the correlation between ages and the presence of inclusions. Considering the enriched contents of S and Cl in nosean, the excess 40Ar could be derived from the common volatile component separated from the magma which provided S and Cl then be trapped in nosean during or after the formation of nosean. References: Lippolt, H. J., M. Troesch and J. C. Hess (1990) Earth Planet. Sci. Lett., 101, 19-33 Sumino, H., K. Ikehata, A. Shimizu, K. Nagao and S. Nakada (2008) J. Volcanol. Geotherm. Res., 175, 189-207

Sudo, Masafumi; Altenberger, Uwe; Günter, Christina

2014-05-01

82

Super Volcano  

NSDL National Science Digital Library

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 volcano. 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.

83

Venus - Rhea Mons Volcano  

NASA Technical Reports Server (NTRS)

Two mosaiced pieces of Magellan image strips display the area east of the Rhea Mons volcano on Venus. This image is centered at about 32.5 degrees north latitude and 286.6 degrees east longitude. The mosaic is 47 kilometers (28 miles) wide and 135 km (81 miles) long. This region has been previously identified as 'tessera' from Earth-based radar (Arecibo) images. The center of the image is dominated by a network of intersecting ridges and valleys. The radar bright north south trending features in this image range from 1 km (0.6 mile) to 3 km (1.8 miles) in length. The average spacing between these ridges is about 1.5 km (0.9 mile). The dark patches at the top of the image are smooth surfaces and may be lava flows located in lowlands between the higher ridge and the valley terrain. This image is a mosaic of two orbits obtained in the first Magellan radar test and played back to Earth to the Deep Space Network stations near Goldstone, Calif. and Canberra, Australia, respectively. The resolution of this image is approximately 120 meters (400 feet).

1990-01-01

84

Venus - Volcano With Massive Landslides  

NASA Technical Reports Server (NTRS)

This Magellan full-resolution mosaic which covers an area 143 by 146 kilometers (89 by 91 miles) is centered at 55 degrees north latitude, 266 degrees east longitude. The bright feature, slightly south of center is interpreted to be a volcano, 15-20 kilometers (9.3 to 12.4 miles) in diameter with a large apron of blocky debris to its right and some smaller aprons to its left. A preferred explanation is that several massive catastrophic landslides dropped down steep slopes and were carried by their momentum out into the smooth, dark lava plains. At the base of the east-facing or largest scallop on the volcano is what appears to be a large block of coherent rock, 8 to 10 kilometers (5 to 6 miles) in length. The similar margin of both the scallop and block and the shape in general is typical of terrestrial slumped blocks (masses of rock which slide and rotate down a slope instead of breaking apart and tumbling). The bright lobe to the south of the volcano may either be a lava flow or finer debris from other landslides. This volcanic feature, characterized by its scalloped flanks is part of a class of volcanoes called scalloped or collapsed domes of which there are more than 80 on Venus. Based on the chute-like shapes of the scallops and the existence of a spectrum of intermediate to well defined examples, it is hypothesized that all of the scallops are remnants of landslides even though the landslide debris is often not visible. Possible explanations for the missing debris are that it may have been covered by lava flows, the debris may have weathered or that the radar may not be recognizing it because the individual blocks are too small

1992-01-01

85

Diurnal variability in turbidity and coral fluorescence on a fringing reef flat: Southern Molokai, Hawaii  

NASA Astrophysics Data System (ADS)

Terrigenous sediment in the nearshore environment can pose both acute and chronic stresses to coral reefs. The reef flat off southern Molokai, Hawaii, typically experiences daily turbidity events, in which trade winds and tides combine to resuspend terrigenous sediment and transport it alongshore. These chronic turbidity events could play a role in restricting coral distribution on the reef flat by reducing the light available for photosynthesis. This study describes the effects of these turbidity events on the Hawaiian reef coral Montipora capitata using in situ diurnal measurements of turbidity, light levels, and chlorophyll fluorescence yield via pulse-amplitude-modulated (PAM) fluorometry. Average surface irradiance was similar in the morning and the afternoon, while increased afternoon turbidity resulted in lower subsurface irradiance, higher fluorescence yield (? F/ Fm'), and lower relative electron transport rates (rETR). Model calculations based on observed light extinction coeffecients suggest that in the absence of turbidity events, afternoon subsurface irradiances would be 1.43 times higher than observed, resulting in rETR for M. capitata that are 1.40 times higher.

Piniak, Gregory A.; Storlazzi, Curt D.

2008-03-01

86

Types of Volcanoes  

NSDL National Science Digital Library

This volcano resource introduces the six-type classification system and points out weaknesses of the classic three-type system. The six types of volcanoes are shield volcanoes, strato volcanoes, rhyolite caldera complexes, monogenetic fields, flood basalts, and mid-ocean ridges. For each type of volcano there is a description of both structure and dynamics along with examples of each. You can account for more than ninty percent of all volcanoes 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.

87

Gravity model studies of Newberry Volcano, Oregon  

USGS Publications Warehouse

Newberry Volcano, a large Quaternary volcano located about 60 km east of the axis of the High Cascades volcanoes in central Oregon, has a coincident positive residual gravity anomaly of about 12 mGals. Model calculations of the gravity anomaly field suggest that the volcano 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 volcano 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 location 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

Gettings, M.E.; Griscom, A.

1988-01-01

88

Interactions Between Separated Volcanoes  

NASA Astrophysics Data System (ADS)

The Japan Meteorological Agency installed and operates a network of borehole strainmeters in south-east Honshu. One of these instruments is on Izu-Oshima, a volcanic island at the northern end of the Izu-Bonin arc. That strainmeter recorded large strain changes associated with the 1986 eruption of Miharayama on the island. Miyake-jima, about 70 km south of Izu-Oshima, erupted in 1983. No deformation monitoring was available on Miyake-jima but several changes occurred in the strain record at Izu-Oshima. There was a clear change in the long-term strain rate 2 days before the Miyake eruption. Frequent short period events recorded by the strainmeter showed a marked change in their character. The Izu-Oshima strainmeter showed that, over the period from 1980 to the 1986 eruption, the amplitude of the solid earth tides increased by almost a factor of two. At the time of the Miyake eruption, the rate of increase of the tidal amplitude also changed. While all of these changes were observed on a single instrument, they are very different types of change. From a number of independent checks, we can be sure that the strainmeter did not experience any change in performance at that time. Thus it recorded a change in deformation behavior in three very different frequency bands: over very long term, at tidal periods ( ~ day) and at very short periods (minutes). It appears that the distant eruption in 1984 had an effect on the magmatic system under Izu-Oshima. More recent tomographic and seismic attenuation work in the Tohoku (northern Honshu) area has show the existence of a low velocity, high attenuation horizontally elongated structure under the volcanic front. If such a structure exists in the similar tectonic setting for these volcanoes, it could provide a mechanism for communication between the volcanoes.

Linde, A. T.; Sacks, I. S.; Kamigaichi, O.

2002-05-01

89

MTU Volcanoes Page  

NSDL National Science Digital Library

Michigan Technological University Volcanoes Page, which is sponsored by the Keweenaw Volcano Observatory, aims to provide information about volcanoes to the public and to complement other informational sites on the Web. Visitors will find information on what a volcano is, currently active volcanoes throughout the world, remote sensing of volcanoes, volcanic humor, and much more. The volcano 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 volcano 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.

90

Geography World - Volcanoes  

NSDL National Science Digital Library

This portal provides links to an extensive list of volcano-related websites for the United States and around the world. Users can access articles, maps, glossaries, webcams, a dictionary of volcanoes, and many other resources.

91

Ol Doinyo Lengai Volcano  

USGS Multimedia Gallery

Scientists from the Volcano Disaster Assistance Program team and the Geological Survey of Tanzania take a sample of the most recent ashfall from Ol Doinyo Lengai as the volcano looms in the background....

92

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.

93

Database for the Geologic Map of Newberry Volcano, Deschutes, Klamath, and Lake Counties, Oregon  

USGS Publications Warehouse

Newberry Volcano, one of the largest Quaternary volcanoes in the conterminous United States, is a broad shield-shaped volcano measuring 60 km north-south by 30 km east-west with a maximum elevation of more than 2 km. Newberry Volcano is the product of deposits from thousands of eruptions, including at least 25 in the past approximately 12,000 years (Holocene Epoch). Newberry Volcano has erupted as recently as 1,300 years ago, but isotopic ages indicate that the volcano began its growth as early as 0.6 million years ago. Such a long eruptive history and recent activity suggest that Newberry Volcano is likely to erupt in the future. This geologic map database of Newberry Volcano distinguishes rocks and deposits based on their composition, age, and lithology.

Bard, Joseph A.; Ramsey, David W.; MacLeod, Norman S.; Sherrod, David R.; Chitwood, Lawrence A.; Jensen, Robert A.

2013-01-01

94

Monitoring Active Volcanoes  

NSDL National Science Digital Library

This United States Geological Survey (USGS) publication discusses the historic and current monitoring of active volcanoes around the globe. Techniques to measure deviations in pressure and stress induced by subterranean magma movement, as well as other technologies, explain the ways in which researchers monitor and predict volcanoes. Case studies of volcanoes such as Mt. St. Helens, El Chichon, Mauna Loa, and others are discussed.

Tilling, Robert

95

A Scientific Excursion: Volcanoes.  

ERIC Educational Resources Information Center

Reviews an educationally valuable and reasonably well-designed simulation of volcanic activity in an imaginary land. VOLCANOES creates an excellent context for learning information about volcanoes and for developing skills and practicing methods needed to study behavior of volcanoes. (Author/JN)

Olds, Henry, Jr.

1983-01-01

96

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.

Jessica Fries-Gaither

97

How Volcanoes Work  

NSDL National Science Digital Library

This educational resource describes the science behind volcanoes and volcanic processes. Topics include volcanic environments, volcano landforms, eruption dynamics, eruption products, eruption types, historical eruptions, and planetary volcanism. There are two animations, over 250 images, eight interactive tests, and a volcano crossword puzzle.

98

USGS Hawaiian Volcano Observatory  

USGS Multimedia Gallery

The USGS Hawaiian Volcano Observatory is perched on the rim of Kilauea Volcano's summit caldera (next to the Thomas A. Jaggar Museum in Hawai'i Volcanoes National Park), providing a spectacular view of the active vent in Halema‘uma‘u Crater....

99

Ice-volcano interactions Eyjafjallajkull volcano, Iceland  

E-print Network

Ice-volcano interactions in Eyjafjallajökull volcano, Iceland Eyjólfur Magnússon1, Magnús Tumi Sciences, University of Iceland, Reykjavík, Iceland 2. Institute of Earth Sciences, University of Iceland, Reykjavík, Iceland 3. Icelandic Coast Guard SPIRIT workshop 29&30 April 2010, Toulouse Picture by Eyjólfur

Berthier, Etienne

100

Coastal circulation and water column properties off Kalaupapa National Historical Park, Molokai, Hawaii, 2008-2010  

USGS Publications Warehouse

More than 2.2 million measurements of oceanographic forcing and the resulting water-column properties were made off U.S. National Park Service's Kalaupapa National Historical Park on the north shore of Molokai, Hawaii, between 2008 and 2010 to understand the role of oceanographic processes on the health and sustainability of the area's marine resources. The tides off the Kalaupapa Peninsula are mixed semidiurnal. The wave climate is dominated by two end-members: large northwest Pacific winter swell that directly impacts the study site, and smaller, shorter-period northeast trade-wind waves that have to refract around the peninsula, resulting in a more northerly direction before propagating over the study site. The currents primarily are alongshore and are faster at the surface than close to the seabed; large wave events, however, tend to drive flow in a more cross-shore orientation. The tidal currents flood to the north and ebb to the south. The waters off the peninsula appear to be a mix of cooler, more saline, deeper oceanic waters and shallow, warmer, lower-salinity nearshore waters, with intermittent injections of freshwater, generally during the winters. Overall, the turbidity levels were low, except during large wave events. The low overall turbidity levels and rapid return to pre-event background levels following the cessation of forcing suggest that there is little fine-grained material. Large wave events likely inhibit the settlement of fine-grained sediment at the site. A number of phenomena were observed that indicate the complexity of coastal circulation and water-column properties in the area and may help scientists and resource managers to better understand the implications of the processes on marine ecosystem health.

Storlazzi, Curt D.; Presto, Katherine; Brown, Eric K.

2011-01-01

101

EAST AFRICA EAST AFRICA  

E-print Network

EAST AFRICA #12;EAST AFRICA Investment Invested in research and student programs in East Africa $2.7+million SHARCNET Access granted to all partner universities in East Africa CIDA UPCD project, Rebuilding of The Africa Institute at The University of Western Ontario (2011) #12;EAST AFRICA Recruitment and Building

Denham, Graham

102

Optimizing Remote Sensing and GIS Tools for Mapping and Managing the Distribution of an Invasive Mangrove (Rhizophora mangle) on South Molokai, Hawaii  

Microsoft Academic Search

In 1902, the Florida red mangrove, Rhizophora mangle L., was introduced to the island of Molokai, Hawaii, and has since colonized nearly 25% of the south coast shoreline. By classifying three kinds of remote sensing imagery, we compared abilities to detect invasive mangrove distributions and to discriminate mangroves from surrounding terrestrial vegetation. Using three analytical techniques, we compared mangrove mapping

Mimi Diorio; Stacy D. Jupiter; Susan A. Cochran; Donald C. Potts

2007-01-01

103

Alaska Volcano Observatory  

USGS Publications Warehouse

Steam plume from the 2006 eruption of Augustine volcano in Cook Inlet, Alaska. Explosive ash-producing eruptions from Alaska's 40+ historically active volcanoes pose hazards to aviation, including commercial aircraft flying the busy North Pacific routes between North America and Asia. The Alaska Volcano Observatory (AVO) monitors these volcanoes to provide forecasts of eruptive activity. AVO is a joint program of the U.S. 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). AVO is one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and public safety. Learn more about Augustine volcano and AVO at http://www.avo.alaska.edu.

Venezky, Dina Y.; Murray, Tom; Read, Cyrus

2008-01-01

104

Geology of Medicine Lake Volcano, Northern California Cascade Range  

USGS Publications Warehouse

Medicine Lake volcano (MLV) is located 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 volcano. Drillhole data indicate that the plateau surface underlying the volcano has been downwarped by 0.5 km under the center of MLV. The volcano may be even larger than the estimated 600 km3, already the largest volcano by volume in the Cascades.

Donnelly-Nolan, Julie

1990-01-01

105

Headless Debris Flows From Mount Spurr Volcano, Alaska  

Microsoft Academic Search

Sometime between June 20 and July 15, 2004-and contemporaneous with an increase of seismicity beneath the volcano, and elevated gas emissions-a sudden release of impounded water from the summit area of Mt. Spurr volcano produced about a dozen separate debris flow lobes emanating from crevasses and bergschrunds in the surface ice several hundred meters down the east-southeast flank from the

R. G. McGimsey; C. A. Neal; C. F. Waythomas; R. Wessels; M. L. Coombs; K. L. Wallace

2004-01-01

106

Chaiten Volcano, Chile  

NASA Technical Reports Server (NTRS)

On May 2, 2008 Chile's Chaiten Volcano 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.

The images were acquired May 24, 2008, cover an area of 37 x 26.5 km, and are located near 42.7 degrees south latitude, 72.7 degrees west longitude.

The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

2008-01-01

107

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

108

The Volcano Adventure Guide  

NASA Astrophysics Data System (ADS)

Adventure travels to volcanoes offer chance encounters with danger, excitement, and romance, plus opportunities to experience scientific enlightenment and culture. To witness a violently erupting volcano and its resulting impacts on landscape, climate, and humanity is a powerful personal encounter with gigantic planetary forces. To study volcano processes and products during eruptions is to walk in the footsteps of Pliny himself. To tour the splendors and horrors of 25 preeminent volcanoes might be the experience of a lifetime, for scientists and nonscientists alike. In The Volcano Adventure Guide, we now have the ultimate tourist volume to lead us safely to many of the world's famous volcanoes and to ensure that we will see the important sites at each one.

Goff, Fraser

2005-05-01

109

Northern Arizona Volcanoes  

NASA Technical Reports Server (NTRS)

Northern Arizona is best known for the Grand Canyon. Less widely known are the hundreds of geologically young volcanoes, 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.

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.

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.

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 volcanoes; 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.

The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

Size: 20.4 by 24.6 kilometers (12.6 by 15.2 miles) Location: 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

2006-01-01

110

Hazardous Phenomena at Volcanoes  

USGS Publications Warehouse

Volcanoes generate a wide variety of phenomena that can alter the Earth's surface and atmosphere and endanger people and property. While most of the natural hazards illustrated and described in this fact sheet are associated with eruptions, some, like landslides, can occur even when a volcano is quiet. Small events may pose a hazard only within a few miles of a volcano, while large events can directly or indirectly endanger people and property tens to hundreds of miles away.

Myers, Bobbie M.; Brantley, Steven R.

1995-01-01

111

Fumarole\\/plume and diffuse CO2 emission from Sierra Negra volcano, Galapagos archipelago  

Microsoft Academic Search

The active shield-volcano Sierra Negra is part of the Galapagos hotspot. Sierra Negra is the largest shield volcano of Isabela Island, hosting a 10 km diameter caldera. Ten historic eruptions have occurred and some involved a frequently visited east caldera rim fissure zone called Volcan Chico. The last volcanic event occurred in October 2005 and lasted for about a week,

E. Padron; P. A. Hernandez Perez; N. Perez; T. Theofilos; G. Melian; J. Barrancos; G. Virgil; H. Sumino; K. Notsu

2009-01-01

112

Fractal properties of tremor and gas piston events observed at Kilauea Volcano, Hawaii  

Microsoft Academic Search

We study the fractal properties of shallow volcanic tremor and gas piston events associated with magma degassing at Kilauea Volcano, Hawaii, using data from two dense short-baseline arrays of seismographs deployed near the active crater of Puu Oo on the east rift of the volcano. We found an upper bound on the fractal dimension of a strange attractor common to

Bernard Chouet; Herbert R. Shaw

1991-01-01

113

Submersible study of mud volcanoes seaward of the Barbados accretionary wedge: sedimentology, structure and rheology  

Microsoft Academic Search

In 1992, the Nautile went to a mud volcano field located east of the Barbados accretionary wedge near 13 ° 50N. Using nannofossil analysis on cores, we determined the sedimentation rate, and provided a new estimation of the age of the mud volcanoes (750,000 years for the oldest one). Six structures have been explored with the submersible Nautile, and manifestations

Sophie Lance; Pierre Henry; Xavier Le Pichon; Siegfried Lallemant; Hervé Chamley; Frauke Rostek; Jean-Claude Faugères; Eliane Gonthier; Karine Olu

1998-01-01

114

Volcanoes: On-Line Edition  

NSDL National Science Digital Library

This is the on-line version of a general interest publication prepared by the United States Geological Survey (USGS). It provides a general introduction to volcanoes and volcanology. Topics include types of volcanoes; types of eruptions; submarine volcanoes; and features associated with volcanic terrains (geysers, hot springs, etc.). There is also discussion of volcanoes and their association to plate tectonics, extraterrestrial volcanoes, monitoring and research efforts, and the impacts of volcanoes on human populations. A text-only version is also available.

115

Yellowstone Volcano Observatory  

USGS Publications Warehouse

Eruption of Yellowstone's Old Faithful Geyser. Yellowstone hosts the world's largest and most diverse collection of natural thermal features, which are the surface expression of magmatic heat at shallow depths in the crust. The Yellowstone system is monitored by the Yellowstone Volcano Observatory (YVO), a partnership among the U.S. Geological Survey (USGS), Yellowstone National Park, and the University of Utah. YVO is one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and public safety. Learn more about Yellowstone and YVO at http://volcanoes.usgs.gov/yvo.

Venezky, Dina Y.; Lowenstern, Jacob

2008-01-01

116

Shiveluch Volcano, Kamchatka Peninsula, Russia  

NASA Technical Reports Server (NTRS)

On the night of June 4, 2001, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) captured this thermal image of the erupting Shiveluch volcano. Located 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 volcano. 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.

Because Kamchatka is located 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 volcanoes that encircles the Pacific Ocean.

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.

The image is located at 56.7 degrees north latitude, 161.3 degrees east longitude.

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.

2001-01-01

117

Alaska Volcano Observatory  

NSDL National Science Digital Library

This is the homepage of the Alaska Volcano 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 volcano. An interactive map also directs users to summaries and activity notifications for selected volcanoes, or through links to webcams and webicorders (recordings of seismic activity). General information on Alaskan volcanoes 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 volcanoes. There is also an online library of references pertinent to Quaternary volcanism in Alaska and an image library.

118

Mangroves and shoreline change on Molokai, Hawaii: Assessing the role of introduced Rhizophora mangle in sediment dynamics and coastal change using remote sensing and GIS  

Microsoft Academic Search

The Florida red mangrove, Rhizophora mangle, was introduced to the high volcanic island of Molokai, Hawaii in 1902 to trap sediment and stabilize eroding coastal mudflats along the island's reef-fringed south coast. This prolific invasive species now occupies 2.4 km2 of inter-tidal land and borders approximately 20% of the south coast shoreline. Integrating the fundamentals of remote sensing and Geographical

Margaret Mary D'Iorio

2003-01-01

119

Habits of a glacier-covered volcano: seismicity patterns and velocity structure of Katla volcano, Iceland  

NASA Astrophysics Data System (ADS)

The Katla volcano, overlain by the Mýrdalsjökull glacier, is one of the most active and hazardous volcanoes in Iceland. Earthquakes show anomalous magnitude-frequency behaviour and mainly occur in two distinct areas: within the oval caldera and around Goðabunga, a bulge on its western flank. The seismicity differs between the areas; earthquakes in Goðabunga are low frequency and shallow whereas those beneath the caldera occur at greater depths and are volcano-tectonic. The seismicity shows seasonal variations but the rates peak at different times in the two areas. A snow budget model, which gives an estimate of the glacial loading, shows good correlation with seismic activity on an annual scale. Data recorded by the permanent network South Iceland Lowland (SIL), as well as by a temporary network, are used to invert for a 3D seismic velocity model underneath Eyjafjallajökull, Goðabunga and the Katla caldera. The tomography resolves a 15 km wide, aseismic, high-velocity structure at a depth of more than 4 km between the Eyjafjallajökull volcano in the west and the Katla volcano in the east. Anomalously low velocities are observed beneath the Katla caldera, which is interpreted as being a significantly fractured area of anomalously high temperature.

Jónsdóttir, Kristín; Tryggvason, Ari; Roberts, Roland; Lund, Björn; Soosalu, Heidi; Böðvarsson, Reynir

120

Thermal and mechanical development of the East African Rift System  

E-print Network

The deep basins, uplifted flanks, and volcanoes of the Western and Kenya rift systems have developed along the western and eastern margins of the 1300 km-wide East African plateau. Structural patterns deduced from field, ...

Ebinger, Cynthia Joan

1988-01-01

121

Active Lava Flow near Hawai'i Volcanoes National Park  

USGS Multimedia Gallery

Areas of flowing lava show up as bright spots in this image of the active lava flow that extends south from the east rift to the ocean, near the eastern boundary of Hawai'i Volcanoes National Park. The image is a composite of a regular photo and a new ARRA-funded thermal infrared camera that will be...

122

Reunion Island Volcano Erupts  

NASA Technical Reports Server (NTRS)

On January 16, 2002, lava that had begun flowing on January 5 from the Piton de la Fournaise volcano on the French island of Reunion abruptly decreased, marking the end of the volcano's most recent eruption. These false color MODIS images of Reunion, located 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 volcano itself is located 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 volcano'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 volcano, with the northwest portion of the island built on the remains of an extinct volcano, and the southeast half built on the basaltic shield of 8,630-foot Piton de la Fournaise. A basaltic shield volcano 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 volcanoes, 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 volcanoes of Mars. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

2002-01-01

123

Shaking up volcanoes  

USGS Publications Warehouse

Most volcanic eruptions that occur shortly after a large distant earthquake do so by random chance. A few compelling cases for earthquake-triggered eruptions exist, particularly within 200 km of the earthquake, but this phenomenon is rare in part because volcanoes must be poised to erupt in order to be triggered by an earthquake (1). Large earthquakes often perturb volcanoes in more subtle ways by triggering small earthquakes and changes in spring discharge and groundwater levels (1, 2). On page 80 of this issue, Brenguier et al. (3) provide fresh insight into the interaction of large earthquakes and volcanoes by documenting a temporary change in seismic velocity beneath volcanoes in Honshu, Japan, after the devastating Tohoku-Oki earthquake in 2011.

Prejean, Stephanie G.; Haney, Matthew M.

2014-01-01

124

Volcanoes in the Infrared  

NSDL National Science Digital Library

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 volcanoes in the Aleutian Islands, Alaska.

2008-11-04

125

A satellite geodetic survey of spatiotemporal deformation of Iranian volcanos  

NASA Astrophysics Data System (ADS)

Surface deformation in volcanic areas is usually due to movement of magma, hydrothermal activity at depth, weight of volcano, landside, etc. Iran, located at the convergence of the Eurasian and Arabian tectonic plates, is the host of five apparently inactive volcanoes, named 'Damavand', 'Taftan', 'Bazman', 'Sabalan' and 'Sahand'. Through investigation of the long term surface deformation rate at Damavand volcano, the highest point in the middle east, Shirzaei et al. (2011) demonstrated that a slow gravity-driven deformation in the form of spreading is going on at this volcano. Extending the earlier work, in this study, I explore large sets of SAR data obtained by Envisat radar satellite from 2003 through 2010 at all Iranian volcanoes. Multitemporal interferometric analysis of the SAR data sets allows retrieving sub-millimeter surface deformation at these volcanic systems. As a result, I detect a transient flank failure in the form of landslide at Damavand that is followed by elevated fumarolic activity. This suggests that landslide might have triggered volcanic unrest. Moreover, I measure significant surface deformation at Taftan and Bazman volcanos associated with different episodes of uplift and subsidence. The inverse model simulations suggest that the time-dependent inflations and deflations of extended and spherical pressurized magma chambers are responsible for the surface displacements at these volcanoes. I also detect time-dependent surface displacements at Sabalan and Sahand volcanoes, where the investigation of the type and the sources of the observed deformation is subject of ongoing research. This study is a best example that shows the absent of recent eruption can not be used as a reliable factor in volcanic hazard assessment and a continuous monitoring system is of vital importance. Reference Shirzaei, M., Walter, T.R., Nankali, H.R. and Holohan, E.P., 2011. Gravity-driven deformation of Damavand volcano, Iran, detected through InSAR time series. Geology, 39(3): 251-254.

Shirzaei, M.

2012-04-01

126

EARTHQUAKES - VOLCANOES (Causes - Forecast - Counteraction)  

NASA Astrophysics Data System (ADS)

Earthquakes and volcanoes are caused by: 1)Various liquid elements (e.g. H20, H2S, S02) which emerge from the pyrosphere and are trapped in the space between the solid crust and the pyrosphere (Moho discontinuity). 2)Protrusions of the solid crust at the Moho discontinuity (mountain range roots, sinking of the lithosphere's plates). 3)The differential movement of crust and pyrosphere. The crust misses one full rotation for approximately every 100 pyrosphere rotations, mostly because of the lunar pull. The above mentioned elements can be found in small quantities all over the Moho discontinuity, and they are constantly causing minor earthquakes and small volcanic eruptions. When large quantities of these elements (H20, H2S, SO2, etc) concentrate, they are carried away by the pyrosphere, moving from west to east under the crust. When this movement takes place under flat surfaces of the solid crust, it does not cause earthquakes. But when these elements come along a protrusion (a mountain root) they concentrate on its western side, displacing the pyrosphere until they fill the space created. Due to the differential movement of pyrosphere and solid crust, a vacuum is created on the eastern side of these protrusions and when the aforementioned liquids overfill this space, they explode, escaping to the east. At the point of their escape, these liquids are vaporized and compressed, their flow accelerates, their temperature rises due to fluid friction and they are ionized. On the Earth's surface, a powerful rumbling sound and electrical discharges in the atmosphere, caused by the movement of the gasses, are noticeable. When these elements escape, the space on the west side of the protrusion is violently taken up by the pyrosphere, which collides with the protrusion, causing a major earthquake, attenuation of the protrusions, cracks on the solid crust and damages to structures on the Earth's surface. It is easy to foresee when an earthquake will occur and how big it is going to be, when we know the record of specific earthquakes and the routes they have followed towards the East. For example, to foresee an earthquake in the Mediterranean region, we take starting point earthquakes to Latin America (0°-40°).The aforementioned elements will reach Italy in an average time period of 49 days and Greece in 53 days. The most reliable preceding phenomenon to determine the epicenter of an earthquake is the rise of the crust's temperature at the area where a large quantity of elements is concentrated, among other phenomena that can be detected either by instruments or by our senses. When there is an active volcano along the route between the area where the "starting-point" earthquake occurred and the area where we expect the same elements to cause a new earthquake, it is possible these elements will escape through the volcano's crater, carrying lava with them. We could contribute to that end, nullifying earthquakes that might be triggered by these elements further to the east, by using manmade resources, like adequate quantities of explosives at the right moment.

Tsiapas, Elias

2014-05-01

127

Earthquakes - Volcanoes (Causes - Forecast - Counteraction)  

NASA Astrophysics Data System (ADS)

Earthquakes and volcanoes are caused by: 1)Various liquid elements (e.g. H20, H2S, S02) which emerge from the pyrosphere and are trapped in the space between the solid crust and the pyrosphere (Moho discontinuity). 2)Protrusions of the solid crust at the Moho discontinuity (mountain range roots, sinking of the lithosphere's plates). 3)The differential movement of crust and pyrosphere. The crust misses one full rotation for approximately every 100 pyrosphere rotations, mostly because of the lunar pull. The above mentioned elements can be found in small quantities all over the Moho discontinuity, and they are constantly causing minor earthquakes and small volcanic eruptions. When large quantities of these elements (H20, H2S, SO2, etc) concentrate, they are carried away by the pyrosphere, moving from west to east under the crust. When this movement takes place under flat surfaces of the solid crust, it does not cause earthquakes. But when these elements come along a protrusion (a mountain root) they concentrate on its western side, displacing the pyrosphere until they fill the space created. Due to the differential movement of pyrosphere and solid crust, a vacuum is created on the eastern side of these protrusions and when the aforementioned liquids overfill this space, they explode, escaping to the east. At the point of their escape, these liquids are vaporized and compressed, their flow accelerates, their temperature rises due to fluid friction and they are ionized. On the Earth's surface, a powerful rumbling sound and electrical discharges in the atmosphere, caused by the movement of the gasses, are noticeable. When these elements escape, the space on the west side of the protrusion is violently taken up by the pyrosphere, which collides with the protrusion, causing a major earthquake, attenuation of the protrusions, cracks on the solid crust and damages to structures on the Earth's surface. It is easy to foresee when an earthquake will occur and how big it is going to be, when we know the record of specific earthquakes and the routes they have followed towards the East. For example, to foresee an earthquake in the Mediterranean region, we take starting point earthquakes to Latin America (0°-40°).The aforementioned elements will reach Italy in an average time period of 49 days and Greece in 53 days. The most reliable preceding phenomenon to determine the epicenter of an earthquake is the rise of the crust's temperature at the area where a large quantity of elements is concentrated, among other phenomena that can be detected either by instruments or by our senses. When there is an active volcano along the route between the area where the "starting-point" earthquake occurred and the area where we expect the same elements to cause a new earthquake, it is possible these elements will escape through the volcano's crater, carrying lava with them. We could contribute to that end, nullifying earthquakes that might be triggered by these elements further to the east, by using manmade resources, like adequate quantities of explosives at the right moment.

Tsiapas, Elias

2013-04-01

128

Preliminary Geologic Map of Newberry Volcano, Oregon  

NASA Astrophysics Data System (ADS)

The late Pleistocene and Holocene rear-arc Newberry Volcano is located in central Oregon east of the Cascades arc axis. Total area covered by the broad, shield-shaped edifice and its accompanying lava field is about 3,200 square kilometers, encompassing all or part of 38 U.S.G.S. 1:24,000-scale quadrangles. Distance from the northernmost extent of lava flows to the southernmost is about 115 km; east-west maximum width is less than 50 km. A printed version of the preliminary map at its intended publication scale of 1:50,000 is 8 ft high by 4 ft wide. More than 200 units have been identified so far, each typically consisting of the lava flow(s) and accompanying vent(s) that represent single eruptive episodes, some of which extend 10’s of kilometers across the edifice. Vents are commonly aligned north-northwest to north-northeast, reflecting a strong regional tectonic influence. The largest individual units on the map are basaltic, some extending nearly 50 km to the north through the cities of Bend and Redmond from vents low on the northern flank of the volcano. The oldest and most distal of the basalts is dated at about 350 ka. Silicic lava flows and domes are confined to the main edifice of the volcano; the youngest rhyolite flows are found within Newberry Caldera, including the rhyolitic Big Obsidian Flow, the youngest flow at Newberry Volcano (~1,300 yr B.P.). The oldest known rhyolite dome is dated at about 400 ka. Andesite units (those with silica contents between 57% and 63%) are the least common, with only 13 recognized to date. The present 6.5 by 8 km caldera formed about 75 ka with the eruption of compositionally-zoned rhyolite to basaltic andesite ash-flow tuff. Older widespread silicic ash-flow tuffs imply previous caldera collapses. Approximately 20 eruptions have occurred at Newberry since ice melted off the volcano in latest Pleistocene time. The mapping is being digitally compiled as a spatial geodatabase in ArcGIS. Within the geodatabase, feature classes have been created representing geologic lines (contacts, faults, lava tubes, etc.), geologic unit polygons, and volcanic vent location points. The geodatabase can be queried to determine the spatial distributions of different rock types, geologic units, and other geologic and geomorphic features. Map colors are being used to indicate compositions. Some map patterns have been added to distinguish the youngest lavas and the ash-flow tuffs. Geodatabase information can be used to better understand the evolution, growth, and potential hazards of the volcano.

Donnelly-Nolan, J. M.; Ramsey, D. W.; Jensen, R. A.; Champion, D. E.; Calvert, A. T.

2010-12-01

129

Hazard maps of Colima volcano, Mexico  

NASA Astrophysics Data System (ADS)

Colima volcano, also known as Volcan de Fuego (19° 30.696 N, 103° 37.026 W), is located on the border between the states of Jalisco and Colima and is the most active volcano in Mexico. Began its current eruptive process in February 1991, in February 10, 1999 the biggest explosion since 1913 occurred at the summit dome. The activity during the 2001-2005 period was the most intense, but did not exceed VEI 3. The activity resulted in the formation of domes and their destruction after explosive events. The explosions originated eruptive columns, reaching attitudes between 4,500 and 9,000 m.a.s.l., further pyroclastic flows reaching distances up to 3.5 km from the crater. During the explosive events ash emissions were generated in all directions reaching distances up to 100 km, slightly affected nearby villages as Tuxpan, Tonila, Zapotlán, Cuauhtemoc, Comala, Zapotitlan de Vadillo and Toliman. During the 2005 this volcano has had an intense effusive-explosive activity, similar to the one that took place during the period of 1890 through 1900. Intense pre-plinian eruption in January 20, 1913, generated little economic losses in the lower parts of the volcano due to low population density and low socio-economic activities at the time. Shows the updating of the volcanic hazard maps published in 2001, where we identify whit SPOT satellite imagery and Google Earth, change in the land use on the slope of volcano, the expansion of the agricultural frontier on the east and southeast sides of the Colima volcano, the population inhabiting the area is approximately 517,000 people, and growing at an annual rate of 4.77%, also the region that has shown an increased in the vulnerability for the development of economic activities, supported by the construction of highways, natural gas pipelines and electrical infrastructure that connect to the Port of Manzanillo to Guadalajara city. The update the hazard maps are: a) Exclusion areas and moderate hazard for explosive events (rockfall) and pyroclastic flows, b) Hazard map of lahars and debris flow, and c) Hazard map of ash-fall. The cartographic and database information obtained will be the basis for updating the Operational Plan of the Colima Volcano by the State Civil & Fire Protection Unit of Jalisco, Mexico, and the urban development plans of surrounding municipalities, in order to reduce their vulnerability to the hazards of the volcanic activity.

Suarez-Plascencia, C.; Nunez-Cornu, F. J.; Escudero Ayala, C. R.

2011-12-01

130

Volcanoes: Coming Up from Under.  

ERIC Educational Resources Information Center

Provides specific information about the eruption of Mt. St. Helens in March 1980. Also discusses how volcanoes are formed and how they are monitored. Words associated with volcanoes are listed and defined. (CS)

Science and Children, 1980

1980-01-01

131

GPS monitoring of Hawaiian Volcanoes  

USGS Multimedia Gallery

The USGS Hawaiian Volcano Observatory uses a variety of ground- and satellite-based techniques to monitor Hawai‘i’s active volcanoes.  Here, an HVO scientist sets up a portable GPS receiver to track surface changes during an island-wide survey of Hawai‘i’s volcanoes. &n...

132

Volcano: Tectonic Environments  

NSDL National Science Digital Library

This site describes where volcanoes are found in terms of plate tectonics and explains why they occur at those locations. S map shows that volcanoes are located 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.

Victor Camp

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

The Worlds Deadliest Volcanoes  

NSDL National Science Digital Library

At this interactive site the student attempts to rate the eruption of a volcano according to the Volcanic Explosive Index (VEI). After seeing the step by step eruption of an actual volcano, the student is introduced to VEI scale, which includes a description of the eruption, volume of ejected material, plume height, eruption type, duration, total known eruptions with that VEI, and an example. Each factor is linked to a section where it is explained in detail. After evaluating all of the factors and rating them, the student selects a VEI number and clicks for feedback. The correct answer is given with an explanation.

135

Optimizing remote sensing and GIS tools for mapping and managing the distribution of an invasive mangrove (Rhizophora mangle) on South Molokai, Hawaii  

USGS Publications Warehouse

In 1902, the Florida red mangrove, Rhizophora mangle L., was introduced to the island of Molokai, Hawaii, and has since colonized nearly 25% of the south coast shoreline. By classifying three kinds of remote sensing imagery, we compared abilities to detect invasive mangrove distributions and to discriminate mangroves from surrounding terrestrial vegetation. Using three analytical techniques, we compared mangrove mapping accuracy for various sensor-technique combinations. ANOVA of accuracy assessments demonstrated significant differences among techniques, but no significant differences among the three sensors. We summarize advantages and disadvantages of each sensor and technique for mapping mangrove distributions in tropical coastal environments.

D'Iorio, M.; Jupiter, S.D.; Cochran, S.A.; Potts, D.C.

2007-01-01

136

Flood-Frequency Estimates for Streams on Kaua`i, O`ahu, Moloka`i, Maui, and Hawai`i, State of Hawai`i  

USGS Publications Warehouse

This study provides an updated analysis of the magnitude and frequency of peak stream discharges in Hawai`i. Annual peak-discharge data collected by the U.S. Geological Survey during and before water year 2008 (ending September 30, 2008) at stream-gaging stations were analyzed. The existing generalized-skew value for the State of Hawai`i was retained, although three methods were used to evaluate whether an update was needed. Regional regression equations were developed for peak discharges with 2-, 5-, 10-, 25-, 50-, 100-, and 500-year recurrence intervals for unregulated streams (those for which peak discharges are not affected to a large extent by upstream reservoirs, dams, diversions, or other structures) in areas with less than 20 percent combined medium- and high-intensity development on Kaua`i, O`ahu, Moloka`i, Maui, and Hawai`i. The generalized-least-squares (GLS) regression equations relate peak stream discharge to quantified basin characteristics (for example, drainage-basin area and mean annual rainfall) that were determined using geographic information system (GIS) methods. Each of the islands of Kaua`i,O`ahu, Moloka`i, Maui, and Hawai`i was divided into two regions, generally corresponding to a wet region and a dry region. Unique peak-discharge regression equations were developed for each region. The regression equations developed for this study have standard errors of prediction ranging from 16 to 620 percent. Standard errors of prediction are greatest for regression equations developed for leeward Moloka`i and southern Hawai`i. In general, estimated 100-year peak discharges from this study are lower than those from previous studies, which may reflect the longer periods of record used in this study. Each regression equation is valid within the range of values of the explanatory variables used to develop the equation. The regression equations were developed using peak-discharge data from streams that are mainly unregulated, and they should not be used to estimate peak discharges in regulated streams. Use of a regression equation beyond its limits will produce peak-discharge estimates with unknown error and should therefore be avoided. Improved estimates of the magnitude and frequency of peak discharges in Hawai`i will require continued operation of existing stream-gaging stations and operation of additional gaging stations for areas such as Moloka`i and Hawai`i, where limited stream-gaging data are available.

Oki, Delwyn S.; Rosa, Sarah N.; Yeung, Chiu W.

2010-01-01

137

Seismic reflection study in the South Korea Plateau, the Ulleung Interplain Gap, and the northern Ulleung Basin: volcano-tectonic implications for Tertiary back-arc evolution in the southern East Sea  

Microsoft Academic Search

Multi-channel seismic reflection data, acquired from the mid-western part of the East Sea, provide evidences for the nature of acoustic basement and overlying sedimentary succession. In the study area, the acoustic basement can be classified into three types, and the sedimentary succession into four seismic units. Type-A acoustic basement is a remnant of rifted continental crust comprising relatively shallow-seated continental

G. Kim; S. Yoon; S. Chough; Y. Kwon; B. Ryu

2010-01-01

138

Shallow S wave attenuation and actively degassing magma beneath Taal Volcano, Philippines  

NASA Astrophysics Data System (ADS)

Volcano, Philippines, is one of the world's most dangerous volcanoes given its history of explosive eruptions and its close proximity to populated areas. A real-time broadband seismic network was recently deployed and has detected volcano-tectonic events beneath Taal. Our source location analysis of these volcano-tectonic events, using onset arrival times and high-frequency seismic amplitudes, points to the existence of a region of strong attenuation near the ground surface beneath the east flank of Volcano Island in Taal Lake. This region is beneath the active fumarolic area and above sources of pressure contributing inflation and deflation, and it coincides with a region of high electrical conductivity. The high-attenuation region matches that inferred from an active-seismic survey conducted at Taal in 1993. These features strongly suggest that the high-attenuation region represents an actively degassing magma body near the surface that has existed for more than 20 years.

Kumagai, Hiroyuki; Lacson, Rudy; Maeda, Yuta; Figueroa, Melquiades S.; Yamashina, Tadashi

2014-10-01

139

Vegetation map of the watersheds between Kawela and Kamal? Gulches, Island of Moloka?i, Hawai?i  

USGS Publications Warehouse

In this document we describe the methods and results of a project to produce a large-scale map of the dominant plant communities for an area of 5,118.5 hectares encompassing the Kawela and Kamal? watersheds on the island of Moloka?i, Hawai?i, using digital image analysis of multi-spectral satellite imagery. Besides providing a base map of the area for land managers to use, this vegetation map serves as spatial background for the U.S. Geological Survey’s (USGS) Moloka?i Ridge-to-Reef project, which is an interdisciplinary study of erosion and sediment transport within these watersheds. A total of 14 mapping units were identified for the Kawela-Kamal? project area. The most widespread units were the ??hi?a montane wet or mesic forest and No vegetation or very sparse grasses/shrubs communities, each present in more than 800 hectares, or 16 percent of the mapping area. Next largest were the Kiawe woodland with alien grass understory and ?A?ali?i dry shrubland units, each of which covered more than 500 hectares, or more than 12 percent of the area; followed by the Mixed native mesic shrubland, ?Ilima and mixed grass dry shrubland, Mixed alien grass with ?ilima shrubs, and the Mixed alien forest with alien shrub/grass understory communities, which ranged in size from approximately 391 to 491 hectares, or 7.6 to 9.6 percent of the project site. The other six mapped units covered less than 170 hectares of the landscape. Six of the map units were dominated by native vegetation, covering a total of 2,535.2 hectares combined, or approximately 50 percent of the project area. The remaining map units were dominated by nonnative species and represent vegetation types that have resulted from invasion and establishment of plant species that had been either purposely or accidently introduced into Hawai?i since humans arrived in these islands more than 1,500 years ago. The preponderance of mapping units that are dominated by alien species of plants is a strong indication of how much anthropogenic disturbance has occurred in this area. The native-dominated ??hi?a forest and uluhe fern communities are probably most similar to the vegetation that was originally found in the upper part of the project area this area. Portions of the mixed mesic native shrub community still persist in the lowland mesic zone, but below that area, the vegetation is either dominated by alien species, or artificially opened by animal grazing and erosion, even in the few units that are still dominated by native species. The map produced for the Kawela to Kamal? watersheds can be used as a baseline for assessing the distribution and abundance of the various plant communities found across this landscape at the time of the imagery (2004). It can also be used to help understand the dynamics of the vegetation and other attributes of this watershed—such as erosion and surface transport of sediment, relative to current and future habitat conditions.

Jacobi, James D.; Ambagis, Stephen

2013-01-01

140

Tech trek: Viewing volcanoes  

NSDL National Science Digital Library

Help students make real-world connections to Earth science concepts such as volcanoes 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!

Christmann, Edwin P.; Wighting, Mervyn J.; Lucking, Robert A.

2005-03-01

141

The Super Volcano Game  

NSDL National Science Digital Library

How would you handle a volcano diasater? In this game, you've just been appointed chief of the Emergency Management Agency for Bluebear County. Everyone is counting on you to handle the eruption of Mount Spur. Download this game to find out. Before you play, make sure Flash is installed on your computer.

British Broadcasting Corporation

142

Volcano evolution on Mars  

NASA Technical Reports Server (NTRS)

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 volcano 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 volcanoes 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 volcanoes. The volcanoes Alba Patera and Olympus Mons are considered in this context, along with some of the older Martian tholi and paterae

Mouginis-Mark, Pete; Wilson, Lionel

1987-01-01

143

The Three Little Volcanoes  

NSDL National Science Digital Library

In this worksheet students identify and label the characteristic features of shield, cinder cone and composite volcanoes. The resource is part of the teacher's guide accompanying the video, NASA Why Files: The Case of the Mysterious Red Light. Lesson objectives supported by the video, additional resources, teaching tips and an answer sheet are included in the teacher's guide.

144

Santa Maria Volcano, Guatemala  

NASA Technical Reports Server (NTRS)

The eruption of Santa Maria volcano in 1902 was one of the largest eruptions of the 20th century, forming a large crater on the mountain's southwest flank. Since 1922, a lava-dome complex, Santiaguito, has been forming in the 1902 crater. Growth of the dome has produced pyroclastic flows as recently as the 2001-they can be identified in this image. The city of Quezaltenango (approximately 90,000 people in 1989) sits below the 3772 m summit. The volcano is considered dangerous because of the possibility of a dome collapse such as one that occurred in 1929, which killed about 5000 people. A second hazard results from the flow of volcanic debris into rivers south of Santiaguito, which can lead to catastrophic flooding and mud flows. More information on this volcano can be found at web sites maintained by the Smithsonian Institution, Volcano World, and Michigan Tech University. ISS004-ESC-7999 was taken 17 February 2002 from the International Space Station using a digital camera. The image is provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Searching and viewing of additional images taken by astronauts and cosmonauts is available at the NASA-JSC Gateway to

2002-01-01

145

Nyamuragira Volcano Erupts  

NASA Technical Reports Server (NTRS)

Nyamuragira volcano erupted on July 26, 2002, spewing lava high into the air along with a large plume of steam, ash, and sulfur dioxide. The 3,053-meter (10,013-foot) volcano is located in eastern Congo, very near that country's border with Rwanda. Nyamuragira is the smaller, more violent sibling of Nyiragongo volcano, which devastated the town of Goma with its massive eruption in January 2002. Nyamuragira is situated just 40 km (24 miles) northeast of Goma. This pair of images was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra satellite, on July 26. The image on the left shows the scene in true color. The small purple box in the upper righthand corner marks the location of Nyamuragira's hot summit. The false-color image on the right shows the plume from the volcano streaming southwestward. This image was made using MODIS' channels sensitive at wavelengths from 8.5 to 11 microns. Red pixels indicate high concentrations of sulphur dioxide. Image courtesy Liam Gumley, Space Science and Engineering Center, University of Wisconsin-Madison

2002-01-01

146

Nyamuragira Volcano Erupts  

NASA Technical Reports Server (NTRS)

Nyamuragira volcano erupted on July 26, 2002, spewing lava high into the air along with a large plume of steam, ash, and sulfur dioxide. The 3,053-meter (10,013-foot) volcano is located in eastern Congo, very near that country's border with Rwanda. Nyamuragira is the smaller, more violent sibling of Nyiragongo volcano, which devastated the town of Goma with its massive eruption in January 2002. Nyamuragira is situated just 40 km (24 miles) northeast of Goma. This true-color image was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra satellite, on July 28, 2002. Nyamuragira is situated roughly in the center of this scene, roughly 100 km south of Lake Edward and just north of Lake Kivu (which is mostly obscured by the haze from the erupting volcano and the numerous fires burning in the surrounding countryside). Due south of Lake Kivu is the long, narrow Lake Tanganyika running south and off the bottom center of this scene.

2002-01-01

147

Digital Geologic Map Database of Medicine Lake Volcano, Northern California  

NASA Astrophysics Data System (ADS)

Medicine Lake volcano, located in the southern Cascades ~55 km east-northeast of Mount Shasta, is a large rear-arc, shield-shaped volcano with an eruptive history spanning nearly 500 k.y. Geologic mapping of Medicine Lake volcano has been digitally compiled as a spatial database in ArcGIS. Within the database, coverage feature classes have been created representing geologic lines (contacts, faults, lava tubes, etc.), geologic unit polygons, and volcanic vent location points. The database can be queried to determine the spatial distributions of different rock types, geologic units, and other geologic and geomorphic features. These data, in turn, can be used to better understand the evolution, growth, and potential hazards of this large, rear-arc Cascades volcano. Queries of the database reveal that the total area covered by lavas of Medicine Lake volcano, which range in composition from basalt through rhyolite, is about 2,200 km2, encompassing all or parts of 27 U.S. Geological Survey 1:24,000-scale topographic quadrangles. The maximum extent of these lavas is about 80 km north-south by 45 km east-west. Occupying the center of Medicine Lake volcano is a 7 km by 12 km summit caldera in which nestles its namesake, Medicine Lake. The flanks of the volcano, which are dotted with cinder cones, slope gently upward to the caldera rim, which reaches an elevation of nearly 2,440 m. Approximately 250 geologic units have been mapped, only half a dozen of which are thin surficial units such as alluvium. These volcanic units mostly represent eruptive events, each commonly including a vent (dome, cinder cone, spatter cone, etc.) and its associated lava flow. Some cinder cones have not been matched to lava flows, as the corresponding flows are probably buried, and some flows cannot be correlated with vents. The largest individual units on the map are all basaltic in composition, including the late Pleistocene basalt of Yellowjacket Butte (296 km2 exposed), the largest unit on the map, whose area is partly covered by a late Holocene andesite flow. Silicic lava flows are mostly confined to the main edifice of the volcano, with the youngest rhyolite flows found in and near the summit caldera, including the rhyolitic Little Glass Mountain (~1,000 yr B.P.) and Glass Mountain (~950 yr B.P.) flows, which are the youngest eruptions at Medicine Lake volcano. In postglacial time, 17 eruptions have added approximately 7.5 km3 to the volcano’s total estimated volume of 600 km3, which may be the largest by volume among Cascade Range volcanoes. The volcano has erupted nine times in the past 5,200 years, a rate more frequent than has been documented at all other Cascade volcanoes except Mount St. Helens.

Ramsey, D. W.; Donnelly-Nolan, J. M.; Felger, T. J.

2010-12-01

148

Space Radar Image of Sakura-Jima Volcano, Japan  

NASA Technical Reports Server (NTRS)

The active volcano Sakura-Jima on the island of Kyushu, Japan is shown in the center of this radar image. The volcano occupies the peninsula in the center of Kagoshima Bay, which was formed by the explosion and collapse of an ancient predecessor of today's volcano. The volcano has been in near continuous eruption since 1955. Its explosions of ash and gas are closely monitored by local authorities due to the proximity of the city of Kagoshima across a narrow strait from the volcano's center, shown below and to the left of the central peninsula in this image. City residents have grown accustomed to clearing ash deposits from sidewalks, cars and buildings following Sakura-jima's eruptions. The volcano is one of 15 identified by scientists as potentially hazardous to local populations, as part of the international 'Decade Volcano' program. The image was acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttle Endeavour on October 9, 1994. SIR-C/X-SAR, a joint mission of the German, Italian and the United States space agencies, is part of NASA's Mission to Planet Earth. The image is centered at 31.6 degrees North latitude and 130.6 degrees East longitude. North is toward the upper left. The area shown measures 37.5 kilometers by 46.5 kilometers (23.3 miles by 28.8 miles). The colors in the image are assigned to different frequencies and polarizations of the radar as follows: red is L-band vertically transmitted, vertically received; green is the average of L-band vertically transmitted, vertically received and C-band vertically transmitted, vertically received; blue is C-band vertically transmitted, vertically received.

1994-01-01

149

Volcano Inflation prior to Gas Explosions at Semeru Volcano, Indonesia  

NASA Astrophysics Data System (ADS)

Semeru volcano in east Java, Indonesia, is well known to exhibit small vulcanian eruptions at the summit crater. Such eruptive activity stopped on April 2009, but volcanic earthquakes started to occur in August and a lava dome was found in the summit crater on November. Since then, lava sometimes flows downward on the slope and small explosions emitting steams from active crater frequently occur every a few to a few tens of minutes. Since the explosions repeatedly occur with short intervals and the active crater is located close to the summit with an altitude of 3676m, the explosions are considered to originate from the gas (steams) from magma itself in the conduit and not to be caused by interactions of magma with the underground water. We installed a tiltmeter at the summit on March 2010 to study the volcanic eruption mechanisms. The tiltmeter (Pinnacle hybrid type, accuracy of measurement is 1 nrad ) was set at a depth of about 1 m around the summit about 500 m north from the active crater. The data stored every 1 s in the internal memory was uploaded every 6 hours by a small data logger with GPS time correction function. More than one thousand gas explosion events were observed for about 2 weeks. We analyze the tilt records as well as seismic signals recorded at stations of CVGHM, Indonesia. The tilt records clearly show uplift of the summit about 20 to 30 seconds before each explosion. Uplifts before large explosions reach to about 20 - 30 n rad, which is almost equivalent to the volume increase of about 100 m^3 beneath the crater. To examine the eruption magnitude dependence on the uplift, we classify the eruptions into five groups based on the amplitudes of seismograms associated with explosions. We stack the tilt records for these groups to reduce noises in the signals and to get general characteristics of the volcano inflations. The results show that the amplitudes of uplifts are almost proportional to the amplitudes of explosion earthquakes while the preceding time of uplift is almost constant (20 s - 30 s). This implies that the inflation rate controls the magnitude of gas explosions. The observed preceding time of inflation prior to gas explosions are much shorter than those for the inflations before magmatic explosions (Nishi et al., 2007; Iguchi et al., 2008), which suggests that the pressurization processes in shallow conduit for gas explosions are different from that for explosions emitting ashes.

Nishimura, T.; Iguchi, M.; Kawaguchi, R.; Surono, S.; Hendrasto, M.; Rosadi, U.

2010-12-01

150

The diversity of mud volcanoes in the landscape of Azerbaijan  

NASA Astrophysics Data System (ADS)

As the natural phenomenon the mud volcanism (mud volcanoes) 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 volcano" (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 volcanoes, globally the mud ones are restricted in distribution; they mainly locate 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 volcanoes 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 volcanoes and in places which were not considered earlier as the traditional places of mud volcanoes development (e.g. West Nile Rive delta). Azerbaijan is the classic region of mud volcanoes development. From over 800 world mud volcanoes 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 volcanoes 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 volcano Toragay, 400 m height). The base diameter is from 100 m to 3-4 km and more. Like the magmatic ones, the mud volcanoes are crowned with crater of convex-plane or deeply-seated shape. In Azerbaijan there are all types of mud volcanoes: active, extinct, buried, submarine, 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 volcanoes of Azerbaijan" (Yakubov et al., 1971). Recently (Aliyev Ad. et al., 2003) it was proposed a quite new morphological classification of mud volcanoes of Azerbaijan. For the first time the mud volcanic manifestations had been defined. Volcanoes are ranged according to morphological signs, crater shape and type of activity.

Rashidov, Tofig

2014-05-01

151

Gelatin Volcanoes: Student Page  

NSDL National Science Digital Library

This is the Student Page of an activity that teaches students how and why magma moves inside volcanoes by injecting colored water into a clear gelatin cast. The Student Page contains the activity preparation instructions and materials list, key words, and a photograph of the experimental setup. There is also an extension activity question that has students predict what will happen when the experiment is run using an elongated model. This activity is part of Exploring Planets in the Classroom's Volcanology section.

152

Shiveluch and Klyuchevskaya Volcanoes  

NASA Technical Reports Server (NTRS)

A distance of about 80 kilometers (50 miles) separates Shiveluch and Klyuchevskaya Volcanoes on Russia's Kamchatka Peninsula. Despite this distance, however, the two acted in unison on April 26, 2007, when the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite caught them both erupting simultaneously. ASTER 'sees' a slightly different portion of the light spectrum than human eyes. Besides a portion of visible light, ASTER detects thermal energy, meaning it can detect volcanic activity invisible to human eyes. Inset in each image above is a thermal infrared picture of the volcano's summit. In these insets, dark red shows where temperatures are coolest, and yellowish-white shows where temperatures are hottest, heated by molten lava. Both insets show activity at the crater. In the case of Klyuchevskaya, some activity at the crater is also visible in the larger image. In the larger images, the landscapes around the volcanoes appear in varying shades of blue-gray. Dark areas on the snow surface are likely stains left over from previous eruptions of volcanic ash. Overhead, clouds dot the sky, casting their shadows on the snow, especially southeast of Shiveluch and northeast of Klyuchevskaya. To the northwest of Klyuchevskaya is a large bank of clouds, appearing as a brighter white than the snow surface. Shiveluch (sometimes spelled Sheveluch) and Klyuchevskaya (sometimes spelled Klyuchevskoy or Kliuchevskoi) are both stratovolcanoes composed of alternating layers of hardened lava, solidified ash, and rocks from earlier eruptions. Both volcanoes rank among Kamchatka's most active. Because Kamchatka is 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. Large-scale plate tectonic activity causing simultaneous volcanic eruptions in Kamchatka is not uncommon.

2007-01-01

153

Yellowstone Volcano Observatory  

NSDL National Science Digital Library

This is the homepage of the United States Geological Survey's (USGS) Yellowstone Volcano Observatory. It features news articles, monitoring information, status reports and information releases, and information on the volcanic history of the Yellowstone Plateau Volcanic Field. Users can access monthly updates with alert levels and aviation warning codes and real-time data on ground deformation, earthquakes, and hydrology. There is also a list of online products and publications, and an image gallery

154

Earthquakes and Volcanoes  

NSDL National Science Digital Library

This unit provides an introduction for younger students on earthquakes, volcanoes, and how they are related. Topics include evidence of continental drift, types of plate boundaries, types of seismic waves, and how to calculate the distance to the epicenter of an earthquake. There is also information on how earthquake magnitude and intensity are measured, and how seismic waves can reveal the Earth's internal structure. A vocabulary list and downloadable, printable student worksheets are provided.

Medina, Philip

155

Tectonic Plates, Earthquakes, and Volcanoes  

NSDL National Science Digital Library

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. Volcanoes and earthquakes both result from the movement of tectonic plates. This interactive feature shows the relationship between earthquakes and volcanoes and the boundaries of tectonic plates. By clicking on a map, viewers can superimpose the locations of plate boundaries, volcanoes and earthquakes.

156

Volcanoes generate devastating waves  

SciTech Connect

Although volcanic eruptions can cause many frightening phenomena, it is often the power of the sea that causes many volcano-related deaths. This destruction comes from tsunamis (huge volcano-generated waves). Roughly one-fourth of the deaths occurring during volcanic eruptions have been the result of tsunamis. Moreover, a tsunami can transmit the volcano'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, location, 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 locations along shores that experience amplified effects from tsunamis.

Lockridge, P. (National Geophysical Data Center, Boulder, CO (USA))

1988-01-01

157

Multiple explosive rhyolite/trachyte eruptions of alkaline-peralkaline Nemrut and dacite/rhyolite eruptions of neighboring subduction zone-related Süphan volcano over 600 000 years: the East Anatolian tephra province  

NASA Astrophysics Data System (ADS)

The active Nemrut stratovolcano (2918 m asl) (Eastern Anatolia) is topped by a spectacular caldera and dominates the area west of huge Lake Van that covers its lower flanks. The stratovolcano has been active explosively for at least ca. 600 ka based on drilling evidence (ICDP Paleovan project). We have identified, correlated and compositionally characterized some 40 fallout sheets on land - none previously known - the largest ones probably with magma volumes exceeding 30 km3(DRE). The alkaline to peralkaline tephras are dominated by anorthoclase, Fe-rich clinopyroxene and fayalite with quartz and aenigmatite in some. Large-volume comenditic to pantelleritic rhyolite eruptions occurred in intervals of 20 000 - 40 000 years with smaller volume trachytic tephra deposits in between reflecting overall fairly constant magma transfer rates periodically fractionating to highly evolved rhyolite in larger magma reservoirs. Many of the ca. 10 widespread ignimbrite sheets, nearly all newly recognized, commonly followed on the heels of rhyolitic fallout sheets. They are more mafic than the underlying fallout deposits, magma mixing being common. Widespread spectacular agglutinates represent a late phase of the youngest large-volume fallout/ignimbrite eruption at ca. 30 ka. Active Süphan stratovolcano (4158 m asl), some 50 km NE of Nemrut and bordering Lake Van to the north, is dominated in contrast by subduction-related chemistry and mineralogy, smaller-volume eruptions and more advanced crystallization of magmas prior to eruption. Chief phenocrysts comprise complex disequilibrium assemblages of clinopyroxene, hypersthene, olivine, strongly zoned plagioclase, biotite and/or amphibole and common clots of fractionating phases. Many of the highly viscous and crystal-laden Süphan magmas were emplaced as domes and debris avalanches next to fallout sheets and ignimbrites. The dominant NE direction of fan axes of partial isopach maps of ca. 15 major fallout deposits reflecting prevailing wind directions for more than half a million years suggest that well-dated tephra markers of alkaline/peralkaline Nemrut, and sofar less well-dated "calcalkaline" Süphan and Ararat volcanoes represent a major tephrostratigraphic framework that should provide for excellent tephra markers in neighboring countries (e.g. Iran, Armenia, Aserbeidschan) and the Caspian Sea.

Schmincke, H.-U.; Sumita, M.; Paleovan scientific Team

2012-04-01

158

Database for the Geologic Map of the Summit Region of Kilauea Volcano, Hawaii  

USGS Publications Warehouse

INTRODUCTION The area covered by this map includes parts of four U.S. Geological Survey (USGS) 7.5' topographic quadrangles (Kilauea Crater, Volcano, Ka`u Desert, and Makaopuhi). It encompasses the summit, upper rift zones, and Koa`e Fault System of Kilauea Volcano and a part of the adjacent, southeast flank of Mauna Loa Volcano. The map is dominated by products of eruptions from Kilauea Volcano, the southernmost of the five volcanoes on the Island of Hawai`i and one of the world's most active volcanoes. At its summit (1,243 m) is Kilauea Crater, a 3 km-by-5 km collapse caldera that formed, possibly over several centuries, between about 200 and 500 years ago. Radiating away from the summit caldera are two linear zones of intrusion and eruption, the east and the southwest rift zones. Repeated subaerial eruptions from the summit and rift zones have built a gently sloping, elongate shield volcano covering approximately 1,500 km2. Much of the volcano lies under water: the east rift zone extends 110 km from the summit to a depth of more than 5,000 m below sea level; whereas, the southwest rift zone has a more limited submarine continuation. South of the summit caldera, mostly north-facing normal faults and open fractures of the Koa`e Fault System extend between the two rift zones. The Koa`e Fault System is interpreted as a tear-away structure that accommodates southward movement of Kilauea's flank in response to distension of the volcano perpendicular to the rift zones. This digital release contains all the information used to produce the geologic map published as USGS Geologic Investigations Series I-2759 (Neal and Lockwood, 2003). The main component of this digital release is a geologic map database prepared using ArcInfo GIS. This release also contains printable files for the geologic map and accompanying descriptive pamphlet from I-2759.

Dutton, Dillon R.; Ramsey, David W.; Bruggman, Peggy E.; Felger, Tracey J.; Lougee, Ellen; Margriter, Sandy; Showalter, Patrick; Neal, Christina A.; Lockwood, John P.

2007-01-01

159

Digital Data for Volcano Hazards at Newberry Volcano, Oregon  

USGS Publications Warehouse

Newberry volcano is a broad shield volcano located 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 volcano'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 volcano 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 volcano. A hazard-zonation map is included to show the areas that will most likely be affected by renewed eruptions. When Newberry volcano 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) volcano hazard data layers used to produce the Newberry volcano hazard map in USGS Open-File Report 97-513 are included in this data set. Scientists at the USGS Cascades Volcano 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 Volcano that were used to estimate the probability of coverage by future lava flows.

Schilling, S.P.; Doelger, S.; Sherrod, D.R.; Mastin, L.G.; Scott, W.E.

2008-01-01

160

Anatomy of a basaltic volcano  

Microsoft Academic Search

Kilauea volcano, in Hawaii, may be the best understood basaltic volcano in the world. Magma rises from a depth of 80 km or more and resides temporarily in near-surface reservoirs: eruption begins when the crust above one of these reservoirs splits open in response to a pressure increase. Repeated rift-zone eruptions compress Kilauea's flanks; after decades of accumulation, the stress

Robert I. Tilling; John J. Dvorak

1993-01-01

161

Earthquakes, Volcanoes, and Plate Tectonics  

NSDL National Science Digital Library

This page consists of two maps of the world, showing how earthquakes define the boundaries of tectonic plates. Volcanoes are also distributed at plate boundaries (the "Ring of Fire" in the Pacific) and at oceanic ridges. It is part of the U.S. Geological Survey's Cascades Volcano Observatory website, which features written material, images, maps, and links to related topics.

162

Gelatin Volcanoes: Teacher Page  

NSDL National Science Digital Library

This is the Teacher Page of an activity that teaches students how and why magma moves inside volcanoes by injecting colored water into a clear gelatin cast. Activity preparation instructions are on the Student Page, while the Teacher Page has background, preparation, and in-class information. An extension activity has the students repeat the experiment using a square bread pan to simulate the original research that was done using elongate models with triangular cross-sections. This activity is part of Exploring Planets in the Classroom's Volcanology section.

163

Long Valley Volcano Observatory  

NSDL National Science Digital Library

This is the homepage of the United States Geological Survey's (USGS) Long Valley Volcano Observatory (LVO). It features a variety of information on the Mono-Inyo Craters volcanic chain in Long Valley Caldera, California. Materials include a current conditions page with status reports, updates and information releases. There is also monitoring data on seismic activity, ground deformation, gases and tree kill, and hydrologic studies. Topical studies include a reference on the most recent eruption in the Inyo chain (about 250 years ago), and information on the Long Valley Exploratory Well. There are also links to USGS fact sheets and other references about the caldera.

164

How Volcanoes Work  

NSDL National Science Digital Library

How Volcanoes Work was constructed and is maintained by Dr. Vic Camp from San Diego State University's Department of Geological Sciences. The site takes a comprehensive look into every aspect of volcanic formations and eruptions, including historical eruptions (Mt. St. Helens) and volcanism on other planets. Well written and designed, this site offers excellent illustrations, photographs, and several multimedia files such as a cross-sectional view of an eruption taking place. Anyone from geology students to lifelong learners will find this site interesting and informative.

Camp, Vic.

2000-01-01

165

Distal volcano-tectonic seismicity near Augustine Volcano  

USGS Publications Warehouse

Clustered earthquakes located 25 km northeast of Augustine Volcano occurred more frequently beginning about 8 months before the volcano?s explosive eruption in 2006. This increase in distal seismicity was contemporaneous with an increase in seismicity directly below the volcano?s vent. Furthermore, the distal seismicity intensified penecontemporaneously with signals in geodetic data that appear to reveal a transition from magmatic inflation of the volcano to dike injection. Focal mechanisms for five events within the distal cluster show strike-slip-fault movement. Directly above the earthquake cluster, shallow (<5 km deep) folds and faults mapped using multichannel seismic-reflection data strike northeast, parallel to the regional structural grain. About 10 km northeast of Augustine Volcano, however, the Augustine-Seldovia arch, an important trans-basin feature, strikes west and intersects the northeast-striking structural zone. We propose that the fault causing the distal earthquake cluster strikes northwest, subparallel to the arch, and is a right-lateral strike-slip fault. Future earthquake monitoring might show whether increasing activity in the remote cluster can aid in making eruption forecasts.

Fisher, Michael A.; Ruppert, Natalia A.; White, Randall A.; Sliter, Ray W.; Wong, Florence L.

2010-01-01

166

Drilling, Construction, Water-Level, and Water-Quality Information for the Kualapuu Deep Monitor Well, 4-0800-01, Molokai, Hawaii  

USGS Publications Warehouse

A monitor well was completed in January 2001 by the U.S. Geological Survey in the Kualapuu area of central Molokai, Hawaii that allows for monitoring the thicknesses of the freshwater body and the upper part of the underlying freshwater-saltwater transition zone. The well was drilled in cooperation with the State Department of Hawaiian Home Lands and the Maui County Department of Water Supply, and is located near the area that supplies much of the drinking water on Molokai. The well is at a ground-surface elevation of about 982 feet and penetrated a 1,585-foot section of soil and volcanic rock to a depth of 603 feet below sea level. Prior to casing, a cave-in caused the bottom 55 feet of the well to be filled with rocks originating from a zone above. Thus, the final well depth reported by the driller was 1,530 feet. Measured water levels in the well during the period from February 1 to July 13, 2001 range from 8.68 to 9.05 feet above sea level. The most recent available water-conductivity profile from July 13, 2001 indicates that the lowest salinity water in the well is in the upper zone from the water table to a depth of about 220 feet below sea level. Below this upper zone, water salinity increases with depth. The water-temperature profile from July 13, 2001 indicates that the lowest temperature water (20.2 degrees Celsius) in the well is located in the upper zone from the water table to a depth of about 200 feet below sea level. Water temperature increases to 24.5 degrees Celsius near the bottom of the measured profile, 507 feet below sea level.

Oki, Delwyn S.; Bauer, Glenn R.

2001-01-01

167

Migration of a Caldera Eruptive Center, Newberry Volcano, Oregon  

NASA Astrophysics Data System (ADS)

Newberry Volcano is located in Deschutes County, Oregon about 35 km south of the city of Bend. It is a bi-modal Quaternary volcano and is one of the largest volcanos in the Cascade Range. The volcano is positioned near the junction of three geologic provinces: the Cascade Range to the west, the High Lava Plains portion of the Basin and Range to the south and east, and the Blue Mountains to the northeast. Newberry Volcano has been active for the past 600,000 years and has had at least two caldera-forming eruptions. The most recent major caldera-related eruptions, resulting in significant silicic ash and pyroclastic deposits, occurred approximately 300,000 and 80,000 years ago. A large-volume basaltic eruption that occurred about 72,000 years ago is represented by the widespread Bend Lavas which extend approximately 70 km to the north of the central caldera. About 6,000 years ago numerous basaltic eruptions occurred along a northwest fracture zone. The most recent eruption, a silicic obsidian flow and associated pumice fall that vented from within the caldera, has been dated at 1,300 ybp. Newberry has been the site of multiple rounds of geothermal exploration over the past 30 years. Geophysical data including gravity, resistivity, and seismic studies collected in the 1980s in early exploration of the volcano have identified anomalous features beneath the west flank of the volcano. Four deep (<2.8km) wells have been drilled on the northern half of the west flank; all of the wells have encountered temperatures in excess of 300°C, however, three of the wells have low permeability and unconnected fractures. The fourth well showed evidence of a hydrothermal system, but the well caved before a flow test could be completed. Recent geophysical analysis coupled with well geochemistry has identified evidence for older nested caldera related eruptive events buried under younger west flank lavas. A strong gravity gradient, a sharp MT boundary, and arcuate surface features from LIDAR coupled with 300-1200m offsets in units between wells is evidence that the caldera has migrated to the east over time. Buried silicic lavas are observed on the west flank; these lavas include McKay Butte, West Flank Dome, and Southwest Flank Dome. If this conclusion is correct, buried volcanic features similar to those observed in the present caldera could be expected under portions of the west flank, now buried by subsequent volcanic units. Hydrothermal systems, as exposed by erosion in older caldera mineral deposits, may be found associated with these features at Newberry.

Frone, Z.; Waibel, A.; Blackwell, D. D.

2012-12-01

168

Explosive Eruptions of Kamchatkan Volcanoes in 2012 and Danger to Aviation  

NASA Astrophysics Data System (ADS)

Strong explosive eruption of volcanoes is the most dangerous for aircraft because in a few hours or days in the atmosphere and the stratosphere can produce about several cubic kilometers of volcanic ash and aerosols. Ash plumes and the clouds, depending on the power of the eruption, the strength and wind speed, can travel thousands of kilometers from the volcano for several days, remaining hazardous to aircraft, as the melting temperature of small particles of ash below the operating temperature of jet engines. There are 30 active volcanoes in the Kamchatka and 6 active volcanoes in the Northern Kuriles, and 4 of them continuously active. In 2012 seven strong explosive eruptions of the Kamchatkan and the Northern Kuriles volcanoes Sheveluch, Bezymianny, Kizimen, Tolbachik, Klyuchevskoy, and Karymsky took place. In addition, higher fumarolic activity of Gorely volcano was observed. The eruptive activity of Sheveluch Volcano began since 1980 (growth of the lava dome) and is continuing at present. Strong explosive events of the volcano occurred in 2012: on January 22-23; on March 16-17; March 25-30 - June 03; and on September 18: ash plumes rose up to 10 km a.s.l. and extended about 200-2000 km to the different directions of the volcano. The eruptive activity of Bezymianny volcano began since 1955, and is continuing at present as growth of the lava dome. Two paroxysmal explosive phases of the eruption occurred on March 08 and September 01: ash plumes rose up to 8-12 km a.s.l. and extended about 1500 km to the east-north-east of the volcano. Eruption of Kizimen volcano began on December 09, 2010, and continues. Strong explosive eruption began in mid-December, 2010, - ash plumes rose up to 10 km a.s.l. and extended > 800 km from the volcano. There are several stages of the eruption: explosive (from 09 December 2010 to mid-January 2011); explosive-effusive (mid-January to mid-June 2011); effusive (mid-January 2011 to September 2012). Extrusive-effusive phase of eruption of the volcano continues at present. Strombolian explosive eruption of Klyuchevskoy volcano began on October 14, 2012, and continues at present. Tolbachik. Explosive-effusive fissure eruption at Tolbachinsky Dol began on November 27, 2012, and continues. Four cinder cones grew at the fissure; lava flows extended about 20 km of vents. Karymsky volcano has been in a state of explosive eruption since 1996. The moderate explosive eruption continued during all 2012. The eruptive activity of Alaid volcano began on October 06 and probably finished in mid- December, 2012. Gas-steam plumes containing small amount of ash rose up to 3 km a.s.l., a small cinder cone grew into summit volcanic crater. Satellite data showed a weak thermal anomaly over the volcano on October-November. Strong fumarolic activity of Gorely volcano began to noting from June 2010 and continues at present. A new vent on the wall of the volcanic active crater was discovered on June 17, 2010. The crater lake disappeared to Summer 2012.

Girina, Olga; Manevich, Alexander; Melnikov, Dmitry; Nuzhdaev, Anton; Demyanchuk, Yury; Petrova, Elena

2013-04-01

169

Active submarine volcano sampled  

NASA Astrophysics Data System (ADS)

On June 4, 1982, two full dredge hauls of fresh olivine basalt were recovered from the upper flanks of Kavachi submarine volcano, Solomon Islands, from water depths of 400 and 900 m. The shallower dredge site was within one-half mile of the active submarine vent evidenced at the surface by an area of slick water, probably caused by gas emissions. Kavachi is a composite stratovolcano located on the ‘trench-slope break’ or ‘outer-arc high’ of the New Georgia Group, approximately 35 km seaward of the main volcanic line and only 30 km landward of the base of the trench inner wall. The volcano has been observed to erupt every year or two for at least the last 30 years (see cover photographs). An island formed in 1952, 1961, 1965, and 1978, but in each case it rapidly eroded below sea level. The latest eruption was observed by Solair pilots during the several weeks up to and including May 18, 1982.

Taylor, Brian

170

Volcano and earthquake hazards in the Crater Lake region, Oregon  

USGS Publications Warehouse

Crater Lake lies in a basin, or caldera, formed by collapse of the Cascade volcano known as Mount Mazama during a violent, climactic eruption about 7,700 years ago. This event dramatically changed the character of the volcano so that many potential types of future events have no precedent there. This potentially active volcanic center is contained within Crater Lake National Park, visited by 500,000 people per year, and is adjacent to the main transportation corridor east of the Cascade Range. Because a lake is now present within the most likely site of future volcanic activity, many of the hazards at Crater Lake are different from those at most other Cascade volcanoes. Also significant are many faults near Crater Lake that clearly have been active in the recent past. These faults, and historic seismicity, indicate that damaging earthquakes can occur there in the future. This report describes the various types of volcano and earthquake hazards in the Crater Lake area, estimates of the likelihood of future events, recommendations for mitigation, and a map of hazard zones. The main conclusions are summarized below.

Bacon, Charles R.; Mastin, Larry G.; Scott, Kevin M.; Nathenson, Manuel

1997-01-01

171

Geology of El Chichon volcano, Chiapas, Mexico  

USGS Publications Warehouse

The (pre-1982) 850-m-high andesitic stratovolcano El Chicho??n, active during Pleistocene and Holocene time, is located in rugged, densely forested terrain in northcentral Chiapas, Me??xico. The nearest neighboring Holocene volcanoes are 275 km and 200 km to the southeast and northwest, respectively. El Chicho??n is built on Tertiary siltstone and sandstone, underlain by Cretaceous dolomitic limestone; a 4-km-deep bore hole near the east base of the volcano penetrated this limestone and continued 770 m into a sequence of Jurassic or Cretaceous evaporitic anhydrite and halite. The basement rocks are folded into generally northwest-trending anticlines and synclines. El Chicho??n is built over a small dome-like structure superposed on a syncline, and this structure may reflect cumulative deformation related to growth of a crustal magma reservoir beneath the volcano. The cone of El Chicho??n consists almost entirely of pyroclastic rocks. The pre-1982 cone is marked by a 1200-m-diameter (explosion?) crater on the southwest flank and a 1600-m-diameter crater apparently of similar origin at the summit, a lava dome partly fills each crater. The timing of cone and dome growth is poorly known. Field evidence indicates that the flank dome is older than the summit dome, and K-Ar ages from samples high on the cone suggest that the flank dome is older than about 276,000 years. At least three pyroclastic eruptions have occurred during the past 1250 radiocarbon years. Nearly all of the pyroclastic and dome rocks are moderately to highly porphyritic andesite, with plagioclase, hornblende and clinopyroxene the most common phenocrysts. Geologists who mapped El Chicho??n in 1980 and 1981 warned that the volcano posed a substantial hazard to the surrounding region. This warning was proven to be prophetic by violent eruptions that occurred in March and April of 1982. These eruptions blasted away nearly all of the summit dome, blanketed the surrounding region with tephra, and sent pyroclastic flows down radial drainages on the flanks of the cone; about 0.3 km3 of material (density of all products normalized to 2.6 g cm-3) was erupted. More debris entered the stratosphere than from any other volcanic eruption within at least the past two decades. Halite and a calcium sulfate mineral (anhydrite?) recovered from the stratospheric cloud, and anhydrite as a common accessory mineral in 1982 juvenile erupted products may reflect contamination of El Chicho??n magma by the evaporite sequence revealed by drilling. ?? 1984.

Duffield, W.A.; Tilling, R.I.; Canul, R.

1984-01-01

172

Mount Rainier active cascade volcano  

NASA Technical Reports Server (NTRS)

Mount Rainier is one of about two dozen active or recently active volcanoes in the Cascade Range, an arc of volcanoes in the northwestern United States and Canada. The volcano is located 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 volcano 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 volcano. 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 volcano 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 volcano are poorly understood.

1994-01-01

173

Eruptive viscosity and volcano morphology  

NASA Technical Reports Server (NTRS)

Terrestrial central volcanoes formed predominantly from lava flows were classified as shields, stratovolcanoes, and domes. Shield volcanoes tend to be large in areal extent, have convex slopes, and are characterized by their resemblance to inverted hellenic war shields. Stratovolcanoes have concave slopes, whereas domes are smaller and have gentle convex slopes near the vent that increase near the perimeter. In addition to these differences in morphology, several other variations were observed. The most important is composition: shield volcanoes tend to be basaltic, stratovolcanoes tend to be andesitic, and domes tend to be dacitic. However, important exceptions include Fuji, Pico, Mayon, Izalco, and Fuego which have stratovolcano morphologies but are composed of basaltic lavas. Similarly, Ribkwo is a Kenyan shield volcano composed of trachyte and Suswa and Kilombe are shields composed of phonolite. These exceptions indicate that eruptive conditions, rather than composition, may be the primary factors that determine volcano morphology. The objective of this study is to determine the relationships, if any, between eruptive conditions (viscosity, erupted volume, and effusion rate) and effusive volcano morphology. Moreover, it is the goal of this study to incorporate these relationships into a model to predict the eruptive conditions of extraterrestrial (Martian) volcanoes based on their morphology.

Posin, Seth B.; Greeley, Ronald

1988-01-01

174

Numerical simulation of tsunami generation by cold volcanic mass flows at Augustine Volcano, Alaska  

USGS Publications Warehouse

Many of the world's active volcanoes are situated on or near coastlines. During eruptions, diverse geophysical mass flows, including pyroclastic flows, debris avalanches, and lahars, can deliver large volumes of unconsolidated debris to the ocean in a short period of time and thereby generate tsunamis. Deposits of both hot and cold volcanic mass flows produced by eruptions of Aleutian arc volcanoes are exposed at many locations along the coastlines of the Bering Sea, North Pacific Ocean, and Cook Inlet, indicating that the flows entered the sea and in some cases may have initiated tsunamis. We evaluate the process of tsunami generation by cold granular subaerial volcanic mass flows using examples from Augustine Volcano in southern Cook Inlet. Augustine Volcano is the most historically active volcano in the Cook Inlet region, and future eruptions, should they lead to debris-avalanche formation and tsunami generation, could be hazardous to some coastal areas. Geological investigations at Augustine Volcano suggest that as many as 12-14 debris avalanches have reached the sea in the last 2000 years, and a debris avalanche emplaced during an A.D. 1883 eruption may have initiated a tsunami that was observed about 80 km east of the volcano at the village of English Bay (Nanwalek) on the coast of the southern Kenai Peninsula. Numerical simulation of mass-flow motion, tsunami generation, propagation, and inundation for Augustine Volcano indicate only modest wave generation by volcanic mass flows and localized wave effects. However, for east-directed mass flows entering Cook Inlet, tsunamis are capable of reaching the more populated coastlines of the southwestern Kenai Peninsula, where maximum water amplitudes of several meters are possible.

Waythomas, C.F.; Watts, P.; Walder, J.S.

2006-01-01

175

Eruption of Shiveluch Volcano, Kamchatka, Russia  

NASA Technical Reports Server (NTRS)

On the night of June 4, 2001 ASTER captured this thermal image of the erupting Shiveluch volcano. Located on Russia's Kamchatka Peninsula, Shiveluch rises to an altitude of 8028'. The active lava dome complex is seen as a bright (hot) area on the summit of the volcano. To the southwest, a second hot area is either a debris avalanche or hot ash deposit. Trailing to the west is a 25 km ash plume, seen as a cold 'cloud' streaming from the summit. At least 60 large eruptions have occurred during the last 10,000 years; the largest historical eruptions were in 1854 and 1964. Because Kamchatka is located along the major aircraft routes between North America/Europe and the Far East, this area is constantly monitored for potential ash hazards to aircraft. 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.

The image is located at 56.7 degrees north latitude, 161.3 degrees east longitude.

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, Calif., 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.

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 volcanoes, 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.

2001-01-01

176

Klyuchevskaya, Volcano, Kamchatka Peninsula, CIS  

NASA Technical Reports Server (NTRS)

Klyuchevskaya, Volcano, Kamchatka Peninsula, CIS (56.0N, 160.5E) is one of several active volcanoes in the CIS and is 15,584 ft. in elevation. Fresh ash fall on the south side of the caldera can be seen as a dirty smudge on the fresh snowfall. Just to the north of the Kamchatka River is Shiveluch, a volcano which had been active a short time previously. There are more than 100 volcanic edifices recognized on Kamchatka, 15 of which are still active.

1991-01-01

177

Soufriere Hills Volcano  

NASA Technical Reports Server (NTRS)

In this ASTER image of Soufriere Hills Volcano 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 volcano's summit.

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.

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.

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 volcanoes; 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.

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.

Size: 40.5 x 40.5 km (25.1 x 25.1 miles) Location: 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

2002-01-01

178

The California Volcano Observatory: monitoring the state's restless volcanoes  

USGS Publications Warehouse

Volcanic eruptions happen in the State of California about as frequently as the largest earthquakes on the San Andreas Fault Zone. At least 10 eruptions have taken place in California in the past 1,000 years—most recently at Lassen Peak in Lassen Volcanic National Park (1914 to 1917) in the northern part of the State—and future volcanic eruptions are inevitable. The U.S. Geological Survey California Volcano Observatory monitors the State's potentially hazardous volcanoes.

Stovall, Wendy K.; Marcaida, Mae; Mangan, Margaret T.

2014-01-01

179

Active high-resolution seismic tomography of compressional wave velocity and attenuation structure at Medicine Lake Volcano, northern California Cascade Range  

USGS Publications Warehouse

Medicine Lake volcano is a basalt through rhyolite shield volcano of the Cascade Range, lying east of the range axis. The Pg wave from eight explosive sources which has traveled upward through the target volume to a dense array of 140 seismographs provides 1- to 2-km resolution in the upper 5 to 7 km of the crust beneath the volcano. The experiment tests the hypothesis that Cascade Range volcanoes of this type are underlain only by small silicic magma chambers. We image a low-velocity low-Q region not larger than a few tens of cubic kilometers in volume beneath the summit caldera, supporting the hypothesis. A shallower high-velocity high-density feature, previously known to be present, is imaged for the first time in full plan view; it is east-west elongate, paralleling a topographic lineament between Medicine Lake volcano and Mount Shasta. Differences between this high-velocity feature and the equivalent feature at Newberry volcano, a volcano in central regon resembling Medicine Lake volcano, may partly explain the scarcity of surface hydrothermal features at Medicine Lake volcano. A major low-velocity low-Q feature beneath the southeast flank of the volcano, in an area with no Holocene vents, is interpreted as tephra, flows, and sediments from the volcano deeply ponded on the downthrown side of the Gillem fault. A high-Q normal-velocity feature beneath the north rim of the summit caldera may be a small, possibly hot, subsolidus intrusion. A high-velocity low-Q region beneath the eastern caldera may be an area of boiling water between the magma chamber and the ponded east flank material. -from Authors

Evans, J.R.; Zucca, J.J.

1988-01-01

180

Space Radar Image of Kiluchevskoi, Volcano, Russia  

NASA Technical Reports Server (NTRS)

This is an image of the area of Kliuchevskoi volcano, Kamchatka, Russia, which began to erupt on September 30, 1994. Kliuchevskoi is the blue triangular peak in the center of the image, towards the left edge of the bright red area that delineates bare snow cover. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on its 88th orbit on October 5, 1994. The image shows an area approximately 75 kilometers by 100 kilometers (46 miles by 62 miles) that is centered at 56.07 degrees north latitude and 160.84 degrees east longitude. North is toward the bottom of the image. The radar illumination is from the top of the image. The Kamchatka volcanoes are among the most active volcanoes in the world. The volcanic zone sits above a tectonic plate boundary, where the Pacific plate is sinking beneath the northeast edge of the Eurasian plate. The Endeavour crew obtained dramatic video and photographic images of this region during the eruption, which will assist scientists in analyzing the dynamics of the recent activity. The colors in this image were obtained using the following radar channels: red represents the L-band (horizontally transmitted and received); green represents the L-band (horizontally transmitted and vertically received); blue represents the C-band (horizontally transmitted and vertically received). In addition to Kliuchevskoi, two other active volcanoes are visible in the image. Bezymianny, the circular crater above and to the right of Kliuchevskoi, contains a slowly growing lava dome. Tolbachik is the large volcano with a dark summit crater near the upper right edge of the red snow covered area. The Kamchatka River runs from right to left across the bottom of the image. The current eruption of Kliuchevskoi included massive ejections of gas, vapor and ash, which reached altitudes of 15,000 meters (50,000 feet). Melting snow mixed with volcanic ash triggered mud flows on the flanks of the volcano. Paths of these flows can be seen as thin lines in various shades of blue and green on the north flank in the center of the image. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI), with the Deutsche Forschungsanstalt fuer Luft und Raumfahrt e.v.(DLR), the major partner in science, operations and data processing of X-SAR.

1994-01-01

181

Mt. Erebus Volcano Observatory  

NSDL National Science Digital Library

The Mt. Erebus Volcano Observatory website offers a plethora of information about the geology, geochemistry, and geophysics research at Mt. Erebus in Antarctica. The site addresses the evolution of Erebus, lava and gas chemistry, seismology, and much more. Students can discover how Mount Erebus's environment changes by examining two day, 30 day, and 365 day records. The Photo Gallery is packed with incredible images of the landscape, geologic features, and the scientific monitoring. Users can view live footage as well as movies of volcanic eruptions and the inner and outer crater. Because the materials are not particularly technical, users can easily learn about volcanology and, more specifically, about scientists' efforts to better understand Mt. Erebus.

182

Moloka'i: Fishponds.  

ERIC Educational Resources Information Center

Designed to help teachers implement marine education in their classrooms, this module provides information regarding a vanishing Hawaiian resource, fishponds. Due to the impact of present day human activities on shoreline areas, the size and number of fishponds have been greatly reduced; therefore, this module focuses on fishponds as a resource…

Hawaii State Dept. of Education, Honolulu. Office of Instructional Services.

183

Iceland: Eyjafjallajökull Volcano  

Atmospheric Science Data Center

... plume, there are some smaller streamers visible to the east (above) it. They are at lower altitude than the main plume. Due to the presence ... the anaglyph gives the erroneous impression that they are below the land surface. A quantitative computer analysis is necessary to ...

2013-04-17

184

What Happened to Our Volcano?  

NSDL National Science Digital Library

One third grade teacher reflects on her students living by the ocean and their frequent jaunts to the beaches where expansive slabs of granite jut out into the sea. During the summer, they run along the rocks and explore the cracks and crevices. Through their geology unit, the students discovered that this granite was formed "inside" a volcano. The students asked, "Why isn't the granite inside the volcano now? Where is the rest of the volcano?" These questions provided the seeds for an investigative approach to "understanding Earth changes." Students were familiar with earthquakes and volcanoes in other regions of the world but never considered how the land beneath their feet had experienced changes over time. This geology unit helped them understand and experience the changing nature of our Earth and the place where they live firsthand.

Mangiante, Elaine S.

2006-12-01

185

Eye in the Sky: Volcanoes  

NSDL National Science Digital Library

This resource presents a brief overview of volcanoes, including the science, phenomena, and effects of volcanic eruptions. Included are video clips and an animation of the Mount Saint Helens eruption.

186

Lung problems and volcano smog  

MedlinePLUS

Volcanic smog (vog) is created when sulfur dioxide and other gases released from a volcano react with oxygen, moisture, dust, and sunlight in the atmosphere. Volcanic smog can irritate the lungs and worsen existing lung ...

187

East African Rift Valley Links for Learning  

NSDL National Science Digital Library

This web page contains links to a collection of resources devoted to the East African Valley Rift, with emphasis on environmental issues and concerns. It lists web addresses by subtopics, in outline form, with a short description to assist the viewer in searching for information. Topics include The Rift Valley, Stromboli online, African volcanoes, the Alid page, paleontology, and many more. The creator of this collection has checked uRLs provided for content and guarantees them to be quality web pages.

Moyra/MysticPC

188

USGS Cascades Volcano Observatory: Maps and Graphics  

NSDL National Science Digital Library

The United States Geological Survey's website for the Cascades Volcano Observatory (CVO) has a host of graphics and maps for the professional volcano researcher or the amateur volcanologist. The maps and graphics are divided into four broad categories, and within each of those categories are dozens and dozens of maps and graphics. The categories include "Hazards, Features, Topics, and Types: Maps and Graphics", "Monitoring: Maps and Graphics", and "Volcano or Region: Maps and Graphics". Visitors should check out "Bachelor", which is in the "Volcano or Region" category, as there is an "Interactive Imagemap" of the Cascade Range Volcanoes. Clicking on any of the images of the volcanoes will reveal a beautiful, aerial photo of the volcano, along with a brief description of the history of the volcano. Additionally, there is a "Planning Your Visit" section that gives online and offline resources to look at before going to the actual volcano.

2010-02-19

189

East Timor  

NSDL National Science Digital Library

This Week's In the News examines the escalation of violence and the proposal for autonomy in the Indonesian province of East Timor. Last weekend, anti-independence militiamen killed dozens of separatist activists in Dili, the East Timorese capital, intensifying the fierce bloodshed and political tumult in the province. The recent massacre is just one of several brutal episodes that have plagued East Timor in the past quarter-century. The people of the embattled island have suffered numerous human rights violations, have endured economic collapse, and have been decimated by guerrilla warfare, famine, and disease. Over 200,000 East Timorese -- or nearly one-fourth of the population -- have died in the troubles, which began in 1975 when Portugal abruptly abandoned East Timor after 400 years of colonial rule. Unstable and vulnerable, the newly independent East Timor was quickly invaded, occupied, and annexed in 1976 by Indonesia, a stronger nation that quashed all subsequent separatist movements. Last January, after years of political oppression, Indonesia's parliament finally succumbed to international pressure and announced that it would grant East Timor either full independence or autonomy within the Indonesian state. The United Nations, although it has never officially recognized Indonesia's sovereignty over East Timor, plans to supervise a vote, tentatively scheduled for July, wherein the East Timorese will determine whether they want full independence or provincial autonomy. Later this week, Foreign Ministers Ali Alatas of Indonesia and Jaime Gama of Portugal are meeting in New York with UN Secretary-General Kofi Annan to discuss the East Timorese autonomy option and plan for the pending UN-monitored poll. However, the recent resurgence of violence between anti- and pro-independence factions in and around Dili threatens the viability of the proposed poll and endangers the stability of East Timor's self-determination. The nine resources discussed offer background information, the latest news, political analysis, and social commentary.

Osmond, Andrew.

1999-01-01

190

Evaluation of volcanic risk management in Merapi and Bromo Volcanoes  

NASA Astrophysics Data System (ADS)

Merapi (Central Java Province) and Bromo (East Java Province) volcanoes have human-environmental systems with unique characteristics, thus causing specific consequences on their risk management. Various efforts have been carried out by many parties (institutional government, scientists, and non-governmental organizations) to reduce the risk in these areas. However, it is likely that most of the actions have been done for temporary and partial purposes, leading to overlapping work and finally to a non-integrated scheme of volcanic risk management. This study, therefore, aims to identify and evaluate actions of risk and disaster reduction in Merapi and Bromo Volcanoes. To achieve this aims, a thorough literature review was carried out to identify earlier studies in both areas. Afterward, the basic concept of risk management cycle, consisting of risk assessment, risk reduction, event management and regeneration, is used to map those earlier studies and already implemented risk management actions in Merapi and Bromo. The results show that risk studies in Merapi have been developed predominantly on physical aspects of volcanic eruptions, i.e. models of lahar flows, hazard maps as well as other geophysical modeling. Furthermore, after the 2006 eruption of Merapi, research such on risk communication, social vulnerability, cultural vulnerability have appeared on the social side of risk management research. Apart from that, disaster risk management activities in the Bromo area were emphasizing on physical process and historical religious aspects. This overview of both study areas provides information on how risk studies have been used for managing the volcano disaster. This result confirms that most of earlier studies emphasize on the risk assessment and only few of them consider the risk reduction phase. Further investigation in this field work in the near future will accomplish the findings and contribute to formulate integrated volcanic risk management cycles for both Merapi and Bromo. Keywords: Risk management, volcanoes hazard, Merapi and Bromo Volcano Indonesia

Bachri, S.; Stöetter, J.; Sartohadi, J.; Setiawan, M. A.

2012-04-01

191

EARTHQUAKES - VOLCANOES(Causes - Forecast - Counteraction)  

NASA Astrophysics Data System (ADS)

Earthquakes and volcanoes are caused by: ?) Various liquid elements (e.g. H20, H2S, S02) which emerge from the pyrosphere and are trapped in the space between the solid crust and the pyrosphere (Moho discontinuity). ?) Protrusions of the solid crust at the Moho discontinuity (mountain range roots, sinking of the lithosphere's plates). C) The differential movement of crust and pyrosphere. The crust misses one full rotation for approximately every 100 pyrosphere rotations, mostly because of the lunar pull. The above mentioned elements can be found in small quantities all over the Moho discontinuity, and they are constantly causing minor earthquakes and small volcanic eruptions. When large quantities of these elements (H20, H2S, SO2, etc) concentrate, they are carried away by the pyrosphere, moving from west to east under the crust. When this movement takes place under flat surfaces of the solid crust, it does not cause earthquakes. But when these elements come along a protrusion (a mountain root) they concentrate on its western side, displacing the pyrosphere until they fill the space created. Due to the differential movement of pyrosphere and solid crust, a vacuum is created on the eastern side of these protrusions and when the aforementioned liquids overfill this space, they explode, escaping to the east. At the point of their escape, these liquids are vaporized and compressed, their flow accelerates, their temperature rises due to fluid friction and they are ionized. On the Earth's surface, a powerful rumbling sound and electrical discharges in the atmosphere, caused by the movement of the gasses, are noticeable. When these elements escape, the space on the west side of the protrusion is violently taken up by the pyrosphere, which collides with the protrusion, causing a major earthquake, attenuation of the protrusions, cracks on the solid crust and damages to structures on the Earth's surface. It is easy to foresee when an earthquake will occur and how big it is going to be, when we know the record of specific earthquakes and the routes they have followed towards the East. For example, to foresee an earthquake in the Mediterranean region, we take starting point earthquakes to Latin America (0°-40°).The aforementioned elements will reach Italy in an average time period of 49 days and Greece in 53 days. The most reliable preceding phenomenon to determine the epicenter of an earthquake is the rise of the crust's temperature at the area where a large quantity of elements is concentrated, among other phenomena that can be detected either by instruments or by our senses. When there is an active volcano along the route between the area where the "starting-point" earthquake occurred and the area where we expect the same elements to cause a new earthquake, it is possible these elements will escape through the volcano's crater, carrying lava with them. We could contribute to that end, nullifying earthquakes that might be triggered by these elements further to the east, by using manmade resources, like adequate quantities of explosives at the right moment.

Tsiapas, E.; Soumelidou, D.; Tsiapas, C.

2012-04-01

192

Deep structure and origin of active volcanoes in China  

NASA Astrophysics Data System (ADS)

Recent geophysical studies have provided important constraints on the deep structure and origin of the active intraplate volcanoes in Mainland China. Magmatism in the western Pacific arc and back-arc areas is caused by the corner flow in the mantle wedge and dehydration of the subducting slab (e.g., Zhao et al., 2009a), while the intraplate magmatism in China has different origins. The active volcanoes in Northeast China (such as the Changbai and Wudalianchi) are caused by hot upwelling in the big mantle wedge (BMW) above the stagnant slab in the mantle transition zone and deep slab dehydration as well (Zhao et al., 2009b). The Tengchong volcano in Southwest China is caused by a similar process in the BMW above the subducting Burma microplate (or Indian plate) (Lei et al., 2009a). The Hainan volcano in southernmost China is a hotspot fed by a lower-mantle plume which may be associated with the Pacific and Philippine Sea slabs' deep subduction in the east and Indian slab's deep subduction in the west down to the lower mantle (Lei et al., 2009b; Zhao, 2009). The stagnant slab finally collapses down to the bottom of the mantle, which can trigger the upwelling of hot mantle materials from the lower mantle to the shallow mantle beneath the subducting slabs and may cause the slab-plume interactions (Zhao, 2009). References Lei, J., D. Zhao, Y. Su, 2009a. Insight into the origin of the Tengchong intraplate volcano and seismotectonics in southwest China from local and teleseismic data. J. Geophys. Res. 114, B05302. Lei, J., D. Zhao, B. Steinberger et al., 2009b. New seismic constraints on the upper mantle structure of the Hainan plume. Phys. Earth Planet. Inter. 173, 33-50. Zhao, D., 2009. Multiscale seismic tomography and mantle dynamics. Gondwana Res. 15, 297-323. Zhao, D., Z. Wang, N. Umino, A. Hasegawa, 2009a. Mapping the mantle wedge and interplate thrust zone of the northeast Japan arc. Tectonophysics 467, 89-106. Zhao, D., Y. Tian, J. Lei, L. Liu, 2009b. Seismic image and origin of the Changbai intraplate volcano in East Asia: Role of big mantle wedge above the stagnant Pacific slab. Phys. Earth Planet. Inter. 173, 197-206.

Zhao, D.

2010-12-01

193

Neotectonics of East Anatolian Plateau (Turkey) and Lesser Caucasus: implication for transition from thrusting to strike-slip faulting  

Microsoft Academic Search

The east Anatolian plateau and the Lesser Caucasus are characterised and shaped by three major structures: (1) NW- and NE-trending dextral to sinistral active strike-slip faults, (2) N-S to NNW-trending fissures and \\/or Plio-Quaternary volcanoes, and (3) a 5-km thick, undeformed Plio-Quaternary continental volcano-sedimentary sequence accumulated in various strike-slip basins. In contrast to the situation in the east Anatolian plateau

Ali Koçyi?it; Ali Y?lmaz; Shota Adamia; Simon Kuloshvili

2001-01-01

194

Chiliques volcano, Chile  

NASA Technical Reports Server (NTRS)

A January 6, 2002 ASTER nighttime thermal infrared image of Chiliques volcano in Chile shows a hot spot in the summit crater and several others along the upper flanks of the edifice, indicating new volcanic activity. Examination of an earlier nighttime thermal infrared image from May 24,2000 showed no thermal anomaly. Chiliques volcano was previously thought to be dormant. Rising to an elevation of 5778 m, Chiliques is a simple stratovolcano with a 500-m-diameter circular summit crater. This mountain is one of the most important high altitude ceremonial centers of the Incas. It is rarely visited due to its difficult accessibility. Climbing to the summit along Inca trails, numerous ruins are encountered; at the summit there are a series of constructions used for rituals. There is a beautiful lagoon in the crater that is almost always frozen.

The daytime image was acquired on November 19, 2000 and was created by displaying ASTER bands 1,2 and 3 in blue, green and red. The nighttime image was acquired January 6, 2002, and is a color-coded display of a single thermal infrared band. The hottest areas are white, and colder areas are darker shades of red. Both images cover an area of 7.5 x 7.5 km, and are centered at 23.6 degrees south latitude, 67.6 degrees west longitude.

Both images cover an area of 7.5 x 7.5 km, and are centered at 23.6 degrees south latitude, 67.6 degrees west longitude.

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.

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.

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 volcanoes; 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.

Size: 7.5 x 7.5 km (4.5 x 4.5 miles) Location: 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

2002-01-01

195

Resistivity Changes of Sakurajima Volcano by Magnetotelluric Continuous Observations  

NASA Astrophysics Data System (ADS)

In order to predict volcano eruptions and to contribute to hazard mitigation, monitoring of subsurface magma movement is the most essential approach. Recent study of time change of seismic structure (4D tomography) in Etna volcano clearly imaged time change of Vp/Vs structure, [Patanè et al., 2006]. They showed that structure changes not only on the location of magma intrusion but widely around the intrusion. They attributed Vp/Vs change to subsurface magma movement and fluids migration from the intrusion zone. Another method using seismic noise records are proposed to monitor the subsurface seismic structure [Brenguier et al., 2008]. These seismic methods have a great potential to reliable prediction of volcano eruption, though the method need densely deployed seismometer network. Monitoring electric resistivity structure is also the promising tools for imaging the subsurface magma movement, because magma and degassed volatile is highly conductive. Indeed, by repeated DC electric measurement using active source field, significant resistivity change is detected before and after the 1986 eruption of Izu-Oshima volcano, and the subsurface magma movement is deduced [Yukutake et al., 1990; Utada, 2003]. In this study, we show the first results of the long term continuous magnetotellurics (MT) observation to monitor the resistivity structure. Because MT impedance is stable and high time resolution [Eisel and Egbert, 2001; Hanekop and Simpson, 2006], the continuous MT observation is suitable to detect subsurface resistivity changes. We conducted long-term MT continuous measurements since May, 2008 to July, 2009 at Sakurajima, which is the most active volcano in Japan. Two observation sites were set up at 3.3km east, and 3km WNW of the summit crater. The obtained MT impedance shows significant apparent resistivity changes, which continues 20~50 days, in the frequency range between 300-1 Hz at the both observation sites. This frequency range corresponds to the depth around sea level, where groundwater is likely to exist. The start of the resistivity changes roughly coincide with the start of the uplift of the summit detected by the underground tunnel tiltmeter, which is one of the most reliable indicators of the subsurface magma intrusion of Sakurajima volcano. A possible cause of the apparent resistivity change is the volatile degassed from rising magma. In this study, we will carefully investigate the cause of the resistivity change of showing various data of volcano activities.

Aizawa, K.; Kanda, W.; Ogawa, Y.; Iguchi, M.; Yokoo, A.

2009-12-01

196

History of the volcanology in the former Netherlands East Indies  

Microsoft Academic Search

The description of the volcanoes in the former Netherlands East Indies are analysed in order of their publication, grouping them into three parts. The first group consists of information from old Javanese sources and incidental communications in travel accounts and the like, dating from the 16th, 17th and 18th century. The second group includes scientific reports from the 19th century

M. Neumann van Padang

1983-01-01

197

Monitoring Volcanic Gases on Kilauea's East Rift Zone  

USGS Multimedia Gallery

Hawaiian Volcano Observatory Geochemist Jeff Sutton and CSAV international volcanology students visit a continuous gas monitoring site on Kilauea's east rift zone during field studies portion of the summer training course. Instrumentation at this site measures ambient concentration of noxious sulfur...

198

Monitoring Volcanic Gases on Kilauea's East Rift Zone II  

USGS Multimedia Gallery

Hawaiian Volcano Observatory Geochemist Jeff Sutton and CSAV international volcanology students visit a continuous gas monitoring site on Kilauea's east rift zone during field studies portion of the summer training course. Instrumentation at this site measures ambient concentration of noxious su...

199

GEOGYNAMICAL SETTING OF THE VIRUNGA VOLCANIC PROVINCE, EAST AFRICA  

Microsoft Academic Search

The mid-Miocene-recently active Virunga volcanic province lies along the northwestern side of the broad, uplifted East African Plateau, which, like the Ethiopian Plateau to the north, is underlain by anomalously hot asthenosphere. We review mechanisms proposed to explain the geological, geophysical, and geochemical characteristics of the uplifted plateaux, providing a geodynamical framework for the active volcanoes of the Virunga volcanic

Cynthia Ebinger; Tanya Furman

200

Ejecta and Landslides from Augustine Volcano Before 2006  

USGS Publications Warehouse

A late Wisconsin volcano erupted onto the Jurassic-Cretaceous sedimentary bedrock of Augustine Island in lower Cook Inlet in Alaska. Olivine basalt interacting with water erupted explosively. Rhyolitic eruptive debris then swept down the south volcano flank while late Wisconsin glaciers from mountians on western mainland surrounded the island. Early to middle Holocene deposits probably erupted onto the island but are now largely buried. About 5,200, 3,750, 3,500 and 2,275 yr B.P. Augustine ash fell 70 to 110 km away. Since about 2,300 yr B.P. several large eruptions deposited coarse-pumice fall beds on the volcano flanks; many smaller eruptions dropped sand and silt ash. The steep summit erupting viscous andesite domes has repeatedly collapsed into rocky avalanches that flowed into the sea. After a collapse, new domes rebuilt the summit. One to three avalanches shed east before about 2,100 yr B.P., two large ones swept east and southeast between about 2,100 and 1,700 yr B.P., and one shed east and east-northeast between 1,700 and 1,450 yr B.P. Others swept into the sea on the volcano's south, southwest, and north-northwest between about 1,450 and 1,100 yr B.P., and pyroclastic fans spread southeast and southwest. Pyroclastic flows and surges poured down the west and south flanks and a debris avalanche plowed into the western sea between about 1,000 and 750 yr B.P. A small debris avalanche shed south-southeast between about 750 and 390 yr B.P., and large lithic pyroclastic flows went southeast. From about 390 to 200 yr B.P., three rocky avalanches swept down the west-northwest, north-northwest, and north flanks. The large West Island avalanche reached far beyond a former sea cliff and initiated a tsunami. Augustine's only conspicuous lava flow erupted on the north flank. In October 1883 a debris avalanche plowed into the sea to form Burr Point on the north-northeast; then came ashfall, pyroclastic surge, and pyroclastic flows. Eruptions in 1935 and 1963-64 grew summit lava domes that shed coarse rubbly lithic pyroclastic flows down the southwest and south flanks. Eruptions in 1976 and 1986 grew domes that shed large pyroclastic flows northeast, north, and north-northwest. The largest debris avalanches off Augustine sweep into

Waitt, Richard B.

2010-01-01

201

Aerogeophysical measurements of collapse-prone hydrothermally altered zones at Mount Rainier volcano  

USGS Publications Warehouse

Hydrothermally altered rocks can weaken volcanoes, increasing the potential for catastrophic sector collapses that can lead to destructive debris flows1. Evaluating the hazards associated with such alteration is difficult because alteration has been mapped on few active volcanoes1-4 and the distribution and severity of subsurface alteration is largely unknown on any active volcano. At Mount Rainier volcano (Washington, USA), collapses of hydrothermally altered edifice flanks have generated numerous extensive debris flows5,6 and future collapses could threaten areas that are now densely populated7. Preliminary geological mapping and remote-sensing data indicated that exposed alteration is contained in a dyke-controlled belt trending east-west that passes through the volcano's summit3-5,8. But here we present helicopter-borne electromagnetic and magnetic data, combined with detailed geological mapping, to show that appreciable thicknesses of mostly buried hydrothermally altered rock lie mainly in the upper west flank of Mount Rainier. We identify this as the likely source for future large debris flows. But as negligible amounts of highly altered rock lie in the volcano's core, this might impede collapse retrogression and so limit the volumes and inundation areas of future debris flows. Our results demonstrate that high-resolution geophysical and geological observations can yield unprecedented views of the three-dimensional distribution of altered rock.

Finn, C.A.; Sisson, T.W.; Deszcz-Pan, M.

2001-01-01

202

Sand Volcano Following Earthquake  

NASA Technical Reports Server (NTRS)

Sand boil or sand volcano measuring 2 m (6.6 ft.) in length erupted in median of Interstate Highway 80 west of the Bay Bridge toll plaza when ground shaking transformed loose water-saturated deposit of subsurface sand into a sand-water slurry (liquefaction) in the October 17, 1989, Loma Prieta earthquake. Vented sand contains marine-shell fragments. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. (Credit: J.C. Tinsley, U.S. Geological Survey)

1989-01-01

203

Ash and Steam, Soufriere Hills Volcano, Monserrat  

NASA Technical Reports Server (NTRS)

International Space Station crew members are regularly alerted to dynamic events on the Earth's surface. On request from scientists on the ground, the ISS crew observed and recorded activity from the summit of Soufriere Hills on March 20, 2002. These two images provide a context view of the island (bottom) and a detailed view of the summit plume (top). When the images were taken, the eastern side of the summit region experienced continued lava growth, and reports posted on the Smithsonian Institution's Weekly Volcanic Activity Report indicate that 'large (50-70 m high), fast-growing, spines developed on the dome's summit. These spines periodically collapsed, producing pyroclastic flows down the volcano's east flank that sometimes reached the Tar River fan. Small ash clouds produced from these events reached roughly 1 km above the volcano and drifted westward over Plymouth and Richmond Hill. Ash predominately fell into the sea. Sulfur dioxide emission rates remained high. Theodolite measurements of the dome taken on March 20 yielded a dome height of 1,039 m.' Other photographs by astronauts of Montserrat have been posted on the Earth Observatory: digital photograph number ISS002-E-9309, taken on July 9, 2001; and a recolored and reprojected version of the same image. Digital photograph numbers ISS004-E-8972 and 8973 were taken 20 March, 2002 from Space Station Alpha and were provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

2002-01-01

204

CQ3. Volcanoes Do volcanoes signal impending eruptions through changes in the  

E-print Network

CQ3. Volcanoes Do volcanoes signal impending eruptions through changes in the temperature and extent of vegetation cover? #12;CQ3: Do volcanoes signal impending eruptions through changes changes in eruptive behavior at already active volcanoes. Rising magma ultimately results in a flux

Christian, Eric

205

Thomas A. Jaggar, Hawaiian Volcano Observatory  

USGS Multimedia Gallery

Thomas A. Jaggar founded the Hawaiian Volcano Observatory in 1912 and served as its Director until 1940.  Shown here in 1925, Jaggar is at work in HVO's first building, which, at the time, was located on the northeast rim of K?lauea Volcano’s summit caldera, near the present-day Volc...

206

Man Against Volcano: The Eruption on Heimaey,  

E-print Network

Man Against Volcano: The Eruption on Heimaey, Vestmannaeyjar, Iceland This booklet was originally published in 1976 under the title "Man Against Volcano:The Eruption on Heimaey, Vestmann Islands, Iceland:Town of Vestmannaeyjar with Helgafell in the right back- ground (photo courtesy of Sólarfilma). #12;Man Against Volcano

Ingólfsson, �lafur

207

Mars from Above: Viewing Volcanoes  

NSDL National Science Digital Library

In this activity, learners create volcanoes like those they have examined on Earth and Mars through images taken by spacecraft. Using baking soda and vinegar, learners model volcanic eruptions and explore the basics of volcanoes, how scientists view and identify these features from space, and reflect on what the presence of volcanoes means about a planetâs interior. This activity is part of a 60-minute set of activities in which learners, ages 8â13, explore and compare the features of Mars and Earth, discuss what the features suggest about the history of Mars, and create a model to help them understand how scientists view and study other worlds--like Mars. The activities help to show why scientists are interested in exploring Mars for evidence of past life, and address the question: "Why are we searching for life on Mars?"

Institute, Lunar A.

2013-01-01

208

Global Volcano Model  

NASA Astrophysics Data System (ADS)

Over 600 million people live close enough to active volcanoes to be affected when they erupt. Volcanic eruptions cause loss of life, significant economic losses and severe disruption to people's lives, as highlighted by the recent eruption of Mount Merapi in Indonesia. The eruption of Eyjafjallajökull, Iceland in 2010 illustrated the potential of even small eruptions to have major impact on the modern world through disruption of complex critical infrastructure and business. The effects in the developing world on economic growth and development can be severe. There is evidence that large eruptions can cause a change in the earth's climate for several years afterwards. Aside from meteor impact and possibly an extreme solar event, very large magnitude explosive volcanic eruptions may be the only natural hazard that could cause a global catastrophe. GVM is a growing international collaboration that aims to create a sustainable, accessible information platform on volcanic hazard and risk. We are designing and developing an integrated database system of volcanic hazards, vulnerability and exposure with internationally agreed metadata standards. GVM will establish methodologies for analysis of the data (eg vulnerability indices) to inform risk assessment, develop complementary hazards models and create relevant hazards and risk assessment tools. GVM will develop the capability to anticipate future volcanism and its consequences. NERC is funding the start-up of this initiative for three years from November 2011. GVM builds directly on the VOGRIPA project started as part of the GRIP (Global Risk Identification Programme) in 2004 under the auspices of the World Bank and UN. Major international initiatives and partners such as the Smithsonian Institution - Global Volcanism Program, State University of New York at Buffalo - VHub, Earth Observatory of Singapore - WOVOdat and many others underpin GVM.

Sparks, R. S. J.; Loughlin, S. C.; Cottrell, E.; Valentine, G.; Newhall, C.; Jolly, G.; Papale, P.; Takarada, S.; Crosweller, S.; Nayembil, M.; Arora, B.; Lowndes, J.; Connor, C.; Eichelberger, J.; Nadim, F.; Smolka, A.; Michel, G.; Muir-Wood, R.; Horwell, C.

2012-04-01

209

Response of reef corals on a fringing reef flat to elevated suspended-sediment concentrations: Moloka?i, Hawai?i  

PubMed Central

A long-term (10 month exposure) experiment on effects of suspended sediment on the mortality, growth, and recruitment of the reef corals Montipora capitata and Porites compressa was conducted on the shallow reef flat off south Moloka?i, Hawai?i. Corals were grown on wire platforms with attached coral recruitment tiles along a suspended solid concentration (SSC) gradient that ranged from 37 mg l?1 (inshore) to 3 mg l?1 (offshore). Natural coral reef development on the reef flat is limited to areas with SSCs less than 10 mg l?1 as previously suggested in the scientific literature. However, the experimental corals held at much higher levels of turbidity showed surprisingly good survivorship and growth. High SSCs encountered on the reef flat reduced coral recruitment by one to three orders of magnitude compared to other sites throughout Hawai?i. There was a significant correlation between the biomass of macroalgae attached to the wire growth platforms at the end of the experiment and percentage of the corals showing mortality. We conclude that lack of suitable hard substrate, macroalgal competition, and blockage of recruitment on available substratum are major factors accounting for the low natural coral coverage in areas of high turbidity. The direct impact of high turbidity on growth and mortality is of lesser importance. PMID:25653896

Jokiel, Paul L.; Storlazzi, Curt D.; Field, Michael E.; Lager, Claire V.; Lager, Dan

2014-01-01

210

Coral Ba/Ca records of sediment input to the fringing reef of the southshore of Moloka'i, Hawai'i over the last several decades  

USGS Publications Warehouse

The fringing reef of southern Moloka’i is perceived to be in decline because of land-based pollution. In the absence of historical records of sediment pollution, ratios of coral Ba/Ca were used to test the hypothesis that sedimentation has increased over time. Baseline Ba/Ca ratios co-vary with the abundance of red, terrigenous sediment visible in recent imagery. The highest values at One Ali’i are near one of the muddiest parts of the reef. This co-varies with the lowest growth rate of all the sites, perhaps because the upstream Kawela watershed was historically leveed all the way to the nearshore, providing a fast-path for sediment delivery. Sites adjacent to small, steep watersheds have ?decadal periodicities whereas sites adjacent to mangrove forests have shorter-period fluctuations that correspond to the periodicity of sediment transport in the nearshore, rather than the watershed. All four sites show a statistically significant upward trend in Ba/Ca.

Prouty, N.G.; Field, M.E.; Stock, J.D.; Jupiter, S.D.; McCulloch, M.

2010-01-01

211

Response of reef corals on a fringing reef flat to elevated suspended-sediment concentrations: Moloka‘i, Hawai‘i  

USGS Publications Warehouse

A long-term (10 month exposure) experiment on effects of suspended sediment on the mortality, growth, and recruitment of the reef corals Montipora capitata and Porites compressa was conducted on the shallow reef flat off south Moloka?i, Hawai?i. Corals were grown on wire platforms with attached coral recruitment tiles along a suspended solid concentration (SSC) gradient that ranged from 37 mg l?1 (inshore) to 3 mg l?1(offshore). Natural coral reef development on the reef flat is limited to areas with SSCs less than 10 mg l?1 as previously suggested in the scientific literature. However, the experimental corals held at much higher levels of turbidity showed surprisingly good survivorship and growth. High SSCs encountered on the reef flat reduced coral recruitment by one to three orders of magnitude compared to other sites throughout Hawai?i. There was a significant correlation between the biomass of macroalgae attached to the wire growth platforms at the end of the experiment and percentage of the corals showing mortality. We conclude that lack of suitable hard substrate, macroalgal competition, and blockage of recruitment on available substratum are major factors accounting for the low natural coral coverage in areas of high turbidity. The direct impact of high turbidity on growth and mortality is of lesser importance.

Jokiel, Paul L.; Rodgers, Ku'ulei S.; Storlazzi, Curt; Field, Michael E.; Lager, Claire V.; Lager, Dan

2014-01-01

212

Surfing for Earthquakes and Volcanoes  

NSDL National Science Digital Library

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 volcanoes and plot locations to determine plate boundaries. Extensions include interpretation of interaction between plate boundaries, causes of earthquakes and volcanoes, 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.

Patty Coe

213

Alaska volcanoes guidebook for teachers  

USGS Publications Warehouse

Alaska’s volcanoes, like its abundant glaciers, charismatic wildlife, and wild expanses inspire and ignite scientific curiosity and generate an ever-growing source of questions for students in Alaska and throughout the world. Alaska is home to more than 140 volcanoes, which have been active over the last 2 million years. About 90 of these volcanoes have been active within the last 10,000 years and more than 50 of these have been active since about 1700. The volcanoes in Alaska make up well over three-quarters of volcanoes in the United States that have erupted in the last 200 years. In fact, Alaska’s volcanoes erupt so frequently that it is almost guaranteed that an Alaskan will experience a volcanic eruption in his or her lifetime, and it is likely they will experience more than one. It is hard to imagine a better place for students to explore active volcanism and to understand volcanic hazards, phenomena, and global impacts. Previously developed teachers’ guidebooks with an emphasis on the volcanoes in Hawaii Volcanoes National Park (Mattox, 1994) and Mount Rainier National Park in the Cascade Range (Driedger and others, 2005) provide place-based resources and activities for use in other volcanic regions in the United States. Along the lines of this tradition, this guidebook serves to provide locally relevant and useful resources and activities for the exploration of numerous and truly unique volcanic landscapes in Alaska. This guidebook provides supplemental teaching materials to be used by Alaskan students who will be inspired to become educated and prepared for inevitable future volcanic activity in Alaska. The lessons and activities in this guidebook are meant to supplement and enhance existing science content already being taught in grade levels 6–12. Correlations with Alaska State Science Standards and Grade Level Expectations adopted by the Alaska State Department of Education and Early Development (2006) for grades six through eleven are listed at the beginning of each activity. A complete explanation, including the format of the Alaska State Science Standards and Grade Level Expectations, is available at the beginning of each grade link at http://www.eed.state.ak.us/tls/assessment/GLEHome.html.

Adleman, Jennifer N.

2011-01-01

214

Using multiplets to track volcanic processes at Kilauea Volcano, Hawaii  

NASA Astrophysics Data System (ADS)

Multiplets, or repeating earthquakes, are commonly observed at volcanoes, particularly those exhibiting unrest. At Kilauea, multiplets have been observed as part of long period (LP) earthquake swarms [Battaglia et al., 2003] and as volcano-tectonic (VT) earthquakes associated with dike intrusion [Rubin et al., 1998]. The focus of most previous studies has been on the precise location of the multiplets based on reviewed absolute locations, a process that can require extensive human intervention and post-processing. Conversely, the detection of multiplets and measurement of multiplet parameters can be done in real-time without human interaction with locations approximated by the stations that best record the multiplet. The Hawaiian Volcano Observatory (HVO) is in the process of implementing and testing an algorithm to detect multiplets in near-real time and to analyze certain metrics to provide enhanced interpretive insights into ongoing volcanic processes. Metrics such as multiplet percent of total seismicity, multiplet event recurrence interval, multiplet lifespan, average event amplitude, and multiplet event amplitude variability have been shown to be valuable in understanding volcanic processes at Bezymianny Volcano, Russia and Mount St. Helens, Washington and thus are tracked as part of the algorithm. The near real-time implementation of the algorithm can be triggered from an earthworm subnet trigger or other triggering algorithm and employs a MySQL database to store results, similar to an algorithm implemented by Got et al. [2002]. Initial results using this algorithm to analyze VT earthquakes along Kilauea's Upper East Rift Zone between September 2010 and August 2011 show that periods of summit pressurization coincide with ample multiplet development. Summit pressurization is loosely defined by high rates of seismicity within the summit and Upper East Rift areas, coincident with lava high stands in the Halema`uma`u lava lake. High percentages, up to 100%, of earthquakes occurring during summit pressurization were part of a multiplet. Percentages were particularly high immediately prior to the March 5 Kamoamoa eruption. Interestingly, many multiplets that were present prior to the Kamoamoa eruption were reactivated during summit pressurization occurring in late July 2011. At a correlation coefficient of 0.7, 90% of the multiplets during the study period had populations of 10 or fewer earthquakes. Between periods of summit pressurization, earthquakes that belong to multiplets rarely occur, even though magma is flowing through the Upper East Rift Zone. Battaglia, J., Got, J. L. and Okubo, P., 2003. Location of long-period events below Kilauea Volcano using seismic amplitudes and accurate relative relocation. Journal of Geophysical Research-Solid Earth, v.108 (B12) 2553. Got, J. L., P. Okubo, R. Machenbaum, and W. Tanigawa (2002), A real-time procedure for progressive multiplet relative relocation at the Hawaiian Volcano Observatory, Bulletin of the Seismological Society of America, 92(5), 2019. Rubin, A. M., D. Gillard, and J. L. Got (1998), A reinterpretation of seismicity associated with the January 1983 dike intrusion at Kilauea Volcano, Hawaii, Journal of Geophysical Research-Solid Earth, 103(B5), 10003.

Thelen, W. A.

2011-12-01

215

United States Geologic Survey: Selected Volcano Information  

NSDL National Science Digital Library

This United States Geological Survey (USGS) Volcano Hazards Program site contains links to selected material related to volcanic hazards. Users can access information about the volcanic hazards program, publications, topical maps of volcanoes world wide, aviation safety reports, volcanic hazard reports, computer software, volcano digital series and educational videos. Several USGS fact sheets are also available for volcanoes in Alaska, Arizona, California, Hawaii, the Pacific Northwest and around the world. Fact sheets can be downloaded as pdf files or html. This site contains a wide variety of comprehensive material on the world's volcanoes and the hazards associated with them.

2007-01-27

216

Mount St. Helens VolcanoCam  

NSDL National Science Digital Library

This webcam shows a static image of Mount St. Helens taken from the Johnston Ridge Observatory. The Observatory and VolcanoCam are located at an elevation of approximately 4,500 feet, about five miles from the volcano. The observer is looking approximately south-southeast across the North Fork Toutle River Valley. The VolcanoCam image automatically updates approximately every five minutes. Other features include current conditions reports, weather updates, an image achive, and eruption movies. In addition, there are frequently asked questions, and information about using the VolcanoCam image and funding for the VolcanoCam.

217

Savage Earth: Out of the Inferno - Volcanoes  

NSDL National Science Digital Library

This article, entitled Mountains of Fire, describes the relationship between the types of volcanic activity and plate movement and the connection between types of volcanoes and how they erupt. The article is supported by a video of an erupting volcano, a photograph of an eruption and an animation depicting pyroclastic flow and the formation of a composite volcano. It is also supported by three sidebars, called Volcanoes of North America, Montserrat: An Island Under Siege, and Volcanoes on other Planets. These sidebars also have videos or photographs to enhance their message.

218

Ibu volcano, a center of spectacular dacite dome growth and long-term continuous eruptive discharges  

NASA Astrophysics Data System (ADS)

Ibu is one of the most isolated and least accessible volcanoes of Indonesia, located on Halmahera Island, in the province of Maluku, East Indonesia. This volcano is one of the most active volcanoes in Indonesia, but remains poorly studied. Since its resuming activity in 1998, Ibu has injected around 0.7 Tg of SO2 into the atmosphere through 60-100 daily eruptive discharges. This long-term eruptive activity is very well retraced by seismic signals that highlight the progressive dome growth and the supply of new magma into Ibu reservoir. The lava dome which is of dacite composition is developing at a rate of 3182 m3 per day. This decadal dome growth of Ibu requires further attention and warrants monitoring as it is a hazard and risk concern.

Saing, Ugan Boyson; Bani, Philipson; Kristianto

2014-08-01

219

Remote sensing and tectonic analysis of active volcanoes in continental arcs  

NASA Astrophysics Data System (ADS)

Variations in arc volcano spatial distribution and morphology are influenced by the crustal structure beneath the arc. In Colombia and Ecuador, most of the active volcanoes lie on or near regional arc-parallel fault zones, and many of the major volcanoes are aligned or elongated parallel to the faults. Two dominant volcano-fault geometry patterns exist: (1) From north to south, the orientation of the fractures and volcano-shapes changes along the arc from primarily north-northwest trending to east-northeast trending; and (2) From west to east, the fault and volcano alignment patterns vary from north-northwest trends at the outer edges of the arc to east-northeast trending in the middle of the arc. The fault and volcano orientation patterns are related to the age and type of crust being faulted during oblique subduction. The regionally active strike-slip faults in the Northern Andes and other arcs provide long-lasting paths for magma ascent that penetrate much deeper through the lithosphere than the secondary features. Local zones of extension and pre-existing fractures in the last several kilometers of lithosphere provide the plumbing that diverts magma slightly away from the primary linear volcanic front. The dissertation also describes a technique for merging multiple remote sensing data sets over the extremely rough terrain of silicic volcanoes. The major focus of this work was on overcoming coregistration errors from geometric distortion induced by local topography. The geometric distortion was compensated for by first creating an accurate base image with a combination of global positioning system (GPS) ground control, high resolution digital elevation models (DEM), and orthorectified aerial photographs. The individual sensor data were then rectified to the new reference base using triangulation geocoding. The final multi-layered, geocoded product is being used to enhance an existing thermal infrared technique for mapping complex textural patterns in silicic domes. Changes in the surface texture of volcanic domes may indicate changes in volatile content or lava extrusion rates. Textural changes on active domes have been difficult to directly observe due to the dangers of continued activity. Mapping the dome textures with remote sensing provides a measure of safety for field investigators.

Wessels, Rick Lee

220

Papers about Volcanoes and Tsunamis  

NSDL National Science Digital Library

Steven N Ward, a Earth Sciences professor at UC-Santa Cruz, provides downloadable PDF versions of his numerous publications about volcanoes and tsunamis as a part of his homepage. Topics include tsunamis caused by earthquakes, underwater landslides, volcanic eruptions, and asteroid impacts, as well as risk assessment and modeling.

Ward, Steven N.

221

Alaska Volcano Observatory's KML Tools  

Microsoft Academic Search

Virtual Globes are now giving the scientific community a new medium to present data, which is compatible across multiple disciplines. They also provide scientists the ability to display their data in real-time, a critical factor in hazard assessment. The Alaska Volcano Observatory remote sensing group has developed Keyhole Markup Language (KML) tools that are used to display satellite data for

L. Valcic; P. W. Webley; J. E. Bailey; J. Dehn

2008-01-01

222

Sulphur budget at Poàs volcano  

Microsoft Academic Search

Poàs volcano has been extensively studied over the last 15 years. Both geochemical and geophysical data have been integrated in order to develop a better understanding of the volcanic processes occurring there. A major feature at Poàs is the presence of a well-developed hydrothermal system and an acidic crater lake. Between 1995 and 2001, the consistency of parameters such as

N. Fournier; G. Williams-Jones; H. Rymer

2001-01-01

223

VOLCANO INSTABILITY AND LATERAL COLLAPSE  

Microsoft Academic Search

Active volcanoes are dynamically evolving structures, the life-cycles of which are punctuated by episodes of flank instability and lateral failure. Such behaviour is now recognised as ubiquitous and lateral collapses are estimated to have occurred at least four times a century over the past 500 years. In the Andes, three quarters of the large volcanic edifices have experienced collapse, while

W. J. McGuire

2003-01-01

224

del Moral & Grishin: Volcanoes137 Chapter 5. P. 137-160, in Ecosystems of Disturbed Ground, L. R. Walker, editor.  

E-print Network

fissure spawned the largest volcanic episode in recorded history (AD 1783), Icelanders starved, summer record and human history. The Santorini, Greece, eruption (ca. BC 1470) probably destroyed Minoan-ocean volcanoes such as Surtsey, Iceland, or rifts, as in East Africa. Converging plates spawn huge earthquakes

del Moral, Roger

225

A Model of Outflow Generation by Hydrothermal Underpressure Drainage in Volcano-Tectonic Environment, Shalbatana Vallis (Mars)  

Microsoft Academic Search

The survey of the Shalbatana Vallis course and the analysis of the distribution of the concentric peripheral and radial systems of faults east of Tharsis allow us to propose a model that demonstrates the effect of volcano-tectonic strains generating crossing fault systems where heat points allowed hydrothermal drainage of confined aquifers and generated headwater systems. This model is qualitatively consistent

Nathalie A. Cabrol; Edmond A. Grin; Gilles Dawidowicz

1997-01-01

226

A Model of Outflow Generation by Hydrothermal Underpressure Drainage in Volcano–Tectonic Environment, Shalbatana Vallis (Mars)  

Microsoft Academic Search

The survey of the Shalbatana Vallis course and the analysis of the distribution of the concentric peripheral and radial systems of faults east of Tharsis allow us to propose a model that demonstrates the effect of volcano–tectonic strains generating crossing fault systems where heat points allowed hydrothermal drainage of confined aquifers and generated headwater systems. This model is qualitatively consistent

Nathalie A. Cabrol; Edmond A. Grin; Gilles Dawidowicz

1997-01-01

227

Space Radar Image of Taal Volcano, Philippines  

NASA Technical Reports Server (NTRS)

This is an image of Taal volcano, near Manila on the island of Luzon in the Philippines. The black area in the center is Taal Lake, which nearly fills the 30-kilometer-diameter (18-mile) caldera. The caldera rim consists of deeply eroded hills and cliffs. The large island in Taal Lake, which itself contains a crater lake, is known as Volcano Island. The bright yellow patch on the southwest side of the island marks the site of an explosion crater that formed during a deadly eruption of Taal in 1965. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on its 78th orbit on October 5, 1994. The image shows an area approximately 56 kilometers by 112 kilometers (34 miles by 68 miles) that is centered at 14.0 degrees north latitude and 121.0 degrees east longitude. North is toward the upper right of the image. The colors in this image were obtained using the following radar channels: red represents the L-band (horizontally transmitted and received); green represents the L-band (horizontally transmitted and vertically received); blue represents the C-band (horizontally transmitted and vertically received). Since 1572, Taal has erupted at least 34 times. Since early 1991, the volcano has been restless, with swarms of earthquakes, new steaming areas, ground fracturing, and increases in water temperature of the lake. Volcanologists and other local authorities are carefully monitoring Taal to understand if the current activity may foretell an eruption. Taal is one of 15 'Decade Volcanoes' that have been identified by the volcanology community as presenting large potential hazards to population centers. The bright area in the upper right of the image is the densely populated city of Manila, only 50 kilometers (30 miles) north of the central crater. Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI), with the Deutsche Forschungsanstalt fuer Luft und Raumfahrt e.v.(DLR), the major partner in science, operations and data processing of X-SAR.

1994-01-01

228

Space Radar Image of Kliuchevskoi Volcano, Russia  

NASA Technical Reports Server (NTRS)

This is an image of the Kliuchevskoi volcano, Kamchatka, Russia, which began to erupt on September 30, 1994. Kliuchevskoi is the bright white peak surrounded by red slopes in the lower left portion of the image. The image was acquired by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar aboard the space shuttle Endeavour on its 25th orbit on October 1, 1994. The image shows an area approximately 30 kilometers by 60 kilometers (18.5 miles by 37 miles) that is centered at 56.18 degrees north latitude and 160.78 degrees east longitude. North is toward the top of the image. The Kamchatka volcanoes are among the most active volcanoes in the world. The volcanic zone sits above a tectonic plate boundary, where the Pacific plate is sinking beneath the northeast edge of the Eurasian plate. The Endeavour crew obtained dramatic video and photographic images of this region during the eruption, which will assist scientists in analyzing the dynamics of the current activity. The colors in this image were obtained using the following radar channels: red represents the L-band (horizontally transmitted and received); green represents the L-band (horizontally transmitted and vertically received); blue represents the C-band (horizontally transmitted and vertically received). The Kamchatka River runs from left to right across the image. An older, dormant volcanic region appears in green on the north side of the river. The current eruption included massive ejections of gas, vapor and ash, which reached altitudes of 20,000 meters (65,000 feet). New lava flows are visible on the flanks of Kliuchevskoi, appearing yellow/green in the image, superimposed on the red surfaces in the lower center. Melting snow triggered mudflows on the north flank of the volcano, which may threaten agricultural zones and other settlements in the valley to the north. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI), with the Deutsche Forschungsanstalt fuer Luft und Raumfahrte.v. (DLR), the major partner in science, operations and data processing of X-SAR.

1994-01-01

229

Iridium emissions from Hawaiian volcanoes  

NASA Technical Reports Server (NTRS)

Particle and gas samples were collected at Mauna Loa volcano during and after its eruption in March and April, 1984 and at Kilauea volcano in 1983, 1984, and 1985 during various phases of its ongoing activity. In the last two Kilauea sampling missions, samples were collected during eruptive activity. The samples were collected using a filterpack system consisting of a Teflon particle filter followed by a series of 4 base-treated Whatman filters. The samples were analyzed by INAA for over 40 elements. As previously reported in the literature, Ir was first detected on particle filters at the Mauna Loa Observatory and later from non-erupting high temperature vents at Kilauea. Since that time Ir was found in samples collected at Kilauea and Mauna Loa during fountaining activity as well as after eruptive activity. Enrichment factors for Ir in the volcanic fumes range from 10,000 to 100,000 relative to BHVO. Charcoal impregnated filters following a particle filter were collected to see if a significant amount of the Ir was in the gas phase during sample collection. Iridium was found on charcoal filters collected close to the vent, no Ir was found on the charcoal filters. This indicates that all of the Ir is in particulate form very soon after its release. Ratios of Ir to F and Cl were calculated for the samples from Mauna Loa and Kilauea collected during fountaining activity. The implications for the KT Ir anomaly are still unclear though as Ir was not found at volcanoes other than those at Hawaii. Further investigations are needed at other volcanoes to ascertain if basaltic volcanoes other than hot spots have Ir enrichments in their fumes.

Finnegan, D. L.; Zoller, W. H.; Miller, T. M.

1988-01-01

230

Lab7: Volcanoes I. --Their Geographic Distribution Introduction  

E-print Network

1 Lab7: Volcanoes I. -- Their Geographic Distribution Introduction Active volcanoes present in understanding these hazards is to realize where active volcanoes actually occur on the Earth's surface. Pacuritin Volcano, Mexico Active Volcanoes of the World South Sandwich Islands. Also known as the Scotia arc

Chen, Po

231

Predictions of turbidity due to enhanced sediment resuspension resulting from sea-level rise on a fringing Coral Reef: Evidence from Molokai, Hawaii  

USGS Publications Warehouse

Accelerating sea-level rise associated with global climate change will affect sedimentary processes on coral reefs and other shoreline environments by increasing energy and sediment resuspension. On reefs, sedimentation is known to increase coral stress and bleaching as particles that settle on coral surfaces interfere with photosynthesis and feeding, and turbidity induced by suspended sediment reduces incident light levels. Using relationships developed from observations of wave orbital velocity, water-surface elevation, and suspended-sediment concentration on a fringing reef flat of Molokai, Hawaii, predictions of the average daily maximum in suspended-sediment concentration increase from ~11 mg/l to ~20 mg/l with 20 cm sea-level rise. The duration of time concentrations exceeds 10 mg/l increases from 9 to 37. An evaluation of the reduction of wave energy flux through breaking and frictional dissipation across the reef flat shows an increase of ~80 relative to the present will potentially reach the shoreline as sea level increases by 20 cm. Where the shoreline exists on low, flat terrain, the increased energy could cause significant erosion of the shoreline. Considering the sediment budget, the sediment flux is predicted to increase and removal of fine-grained sediment may be expedited on some fringing reefs, and sediment in storage on the inner reef could ultimately be reduced. However, increased shoreline erosion may add sediment and offset removal from the reef flat. The shifts in sediment availability and transport that will occur as result of a modest increase in sea level have wide application to fringing coral reefs elsewhere, as well as other shoreline environments. ?? 2010 the Coastal Education & Research Foundation (CERF).

Ogston, A.S.; Field, M.E.

2010-01-01

232

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

233

Communication Between Volcanoes: a Possible Path  

NASA Astrophysics Data System (ADS)

The Japan Meteorological Agency installed and operates a network of Sacks-Evertson type borehole strainmeters in south-east Honshu. One of these instruments is on Izu-Oshima, a volcanic island at the northern end of the Izu-Bonin arc. That strainmeter recorded large strain changes associated with the 1986 eruption of Miharayama on the island and, over the period from 1980 to the 1986 eruption, the amplitude of the solid earth tides changed by almost a factor of two. Miyake-jima, about 75 km south of Izu-Oshima, erupted in October 1983. No deformation monitoring was available on Miyake but several changes occurred in the strain record at Izu-Oshima. There was a clear decrease in amplitude of the long-term strain rate. Short period (~hour) events recorded by the strainmeter became much more frequent about 6 months before the Miyake eruption and ceased following the eruption. At the time of the Miyake eruption, the rate of increase of the tidal amplitude also decreased. While all of these changes were observed on a single instrument, they are very different types of change. From a number of independent checks, we can be sure that the strainmeter did not experience any change in performance at that time. Thus it recorded a change in deformation behavior in three very different frequency bands: over very long term, at tidal periods (~day) and at very short periods (~hour). It appears that the distant eruption in 1983 had an effect on the magmatic system under Izu-Oshima. It is likely that these changes were enhanced to the observed level because Izu-Oshima was itself close to eruption failure. More recent tomographic and seismic attenuation work in the Tohoku (northern Honshu) area has shown the existence of a low velocity, high attenuation horizontally elongated structure under the volcanic front. This zone, likely to contain partial melt, is horizontally continuous along the front. If such a structure exists in the similar tectonic setting for these volcanoes, it could provide a mechanism for communication between the volcanoes.

Linde, A. T.; Sacks, I. S.

2002-12-01

234

Volcanoes: Local Hazard, Global Issue  

NSDL National Science Digital Library

In this module, students can explore two ways that volcanoes affect Earth: by directly threatening people and the environments adjacent to them, and by ejecting aerosols into the atmosphere. The module consists of three investigations in which they will study the local effects of volcanism using images of Mount St. Helens, examine how the effects of volcanic activity can be remotely sensed and monitored from space using NASA data for Mount Spurr in Alaska, and see how geography and spatial perspective are useful in addressing global issues in the tracking and mapping of aerosol hazards such as the ash cloud emitted by the 1989 eruption on Redoubt Volcano. Each investigation is complete with overview, a list of materials and supplies, content preview, classroom procedures, worksheets, background, and evaluation.

235

The USGS Hawaiian Volcano Observatory Monitors Klauea's Summit Eruption  

USGS Multimedia Gallery

The USGS Hawaiian Volcano Observatory (foreground) is located on the caldera rim of Kilauea Volcano, Hawai'i?the most active volcano in the world.  The observatory's location provides an excellent view of summit eruptive activity, which began in 2008....

236

The USGS Hawaiian Volcano Observatory Monitors Kilauea's Summit Eruption  

USGS Multimedia Gallery

The USGS Hawaiian Volcano Observatory (foreground) is located on the caldera rim of Kilauea Volcano, Hawai'i?the most active volcano in the world.  The observatory's location provides an excellent view of summit eruptive activity, which began in 2008....

237

2. PARKING LOT AT JAGGAR MUSEUM, VOLCANO OBSERVATORY. VIEW OF ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. PARKING LOT AT JAGGAR MUSEUM, VOLCANO OBSERVATORY. VIEW OF MEDIAN. NOTE VOLCANIC STONE CURBING (EDGING) TYPICAL OF MOST PARKING AREAS; TRIANGLING AT END NOT TYPICAL. MAUNA LOA VOLCANO IN BACK. - Crater Rim Drive, Volcano, Hawaii County, HI

238

East Africa  

NASA Technical Reports Server (NTRS)

This image shows the East African nations of Ethiopia, Eritrea, and Somalia, as well as portions of Kenya, Sudan, Yemen, and Saudi Arabia. Dominating the scene are the green Ethiopian Highlands. With altitudes as high as 4,620 meters (15,157 feet), the highlands pull moisture from the arid air, resulting in relatively lush vegetation. In fact, coffee-one of the world's most prized crops-originated here. To the north (above) the highlands is Eritrea, which became independent in 1993. East (right) of Ethiopia is Somalia, jutting out into the Indian Ocean. The Sea-viewing Wide Field-of-view Sensor (SeaWiFS) captured this true-color image on November 29, 2000. Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

2002-01-01

239

Flank tectonics of Martian volcanoes  

SciTech Connect

On the flanks of Olympus Mons is a series of terraces, concentrically distributed around the caldera. Their morphology and location 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 volcano. 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 volcanoes on Mars, Ascraeus Mons, Arsia Mons, and Pavonis Mons, possess similar terraces. Extending the analysis to other Martian volcanoes, 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.

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))

1990-08-30

240

Middle East  

SciTech Connect

Petroleum production in Middle East countries during 1980 totaled 6,747,719,000 bbl or an average rate of 18,436,390,000 bbl/d, down 13.9% from 1979. Increases were in Saudi Arabia and Syria. Significant decreases occurred in Iraq, Iran, Kuwait, and Turkey. New discoveries were made in Abu Dhabi, Iran, Saudi Arabia, Sharjah, and Oman. New areas were explored in Bahrain, Oman, Syria, and Yemen. 9 figures, 16 tables.

Hemer, D.O. (Mobil Oil Corp., New York, NY); Mason, J.F.; Hatch, G.C.

1981-10-01

241

Update of the volcanic risk map of Colima volcano, Mexico  

NASA Astrophysics Data System (ADS)

The Colima volcano, located in western Mexico (19° 30.696 N, 103° 37.026 W) began its current eruptive process in February 10, 1999. This event was the basis for the development of two volcanic hazard maps: one for ballistics (rock fall) lahars, and another one for ash fall. During the period of 2003 to 2008 this volcano has had an intense effusive-explosive activity, similar to the one that took place during the period of 1890 through 1900. Intense pre-Plinian eruption in January 20, 1913, generated little economic losses in the lower parts of the volcano thanks to the low population density and low socio-economic activities at the time The current volcanic activity has triggered ballistic projections, pyroclastic and ash flows, and lahars, all have exceeded the maps limits established in 1999. Vulnerable elements within these areas have gradually changed due to the expansion of the agricultural frontier on the east and southeast sides of the Colima volcano. On the slopes of the northwest side, new blue agave Tequilana weber and avocado orchard crops have emerged along with important production of greenhouse tomato, alfalfa and fruit (citrus) crops that will eventually be processed and dried for exportation to the United States and Europe. Also, in addition to the above, large expanses of corn and sugar cane have been planted on the slopes of the volcano since the nineteenth century. The increased agricultural activity has had a direct impact in the reduction of the available forest land area. Coinciding with this increased activity, the 0.8% growth population during the period of 2000 - 2005, - due to the construction of the Guadalajara-Colima highway-, also increased this impact. The growth in vulnerability changed the level of risk with respect to the one identified in the year 1999 (Suarez, 2000), thus motivating us to perform an update to the risk map at 1:25,000 using vector models of the INEGI, SPOT images of different dates, and fieldwork done in order to obtain new agricultural development and socioeconomic status data.

Suarez-Plascencia, C.; Nuñez Cornu, F. J.; Marquez-Azua, B.

2010-12-01

242

East Asia: Seismotectonics, magmatism and mantle dynamics  

NASA Astrophysics Data System (ADS)

In this article, we review the significant recent results of geophysical studies and discuss their implications on seismotectonics, magmatism, and mantle dynamics in East Asia. High-resolution geophysical imaging revealed structural heterogeneities in the source areas of large crustal earthquakes, which may reflect magma and fluids that affected the rupture nucleation of large earthquakes. In subduction zone regions, the crustal fluids originate from the dehydration of the subducting slab. Magmatism in arc and back-arc areas is caused by the corner flow in the mantle wedge and dehydration of the subducting slab. The intraplate magmatism has different origins. The continental volcanoes in Northeast Asia (such as Changbai and Wudalianchi) seem to be caused by the corner flow in the big mantle wedge (BMW) above the stagnant slab in the mantle transition zone and the deep dehydration of the stagnant slab as well. The Tengchong volcano in Southwest China is possibly caused by a similar process in BMW above the subducting Burma microplate (or Indian plate). The Hainan volcano in southernmost China seems to be a hotspot fed by a lower-mantle plume associated with the Pacific and Philippine Sea slabs' deep subduction in the east and the Indian slab's deep subduction in the west down to the lower mantle. The occurrence of deep earthquakes under the Japan Sea and the East Asia margin may be related to a metastable olivine wedge in the subducting Pacific slab. The stagnant slab finally collapses down to the bottom of the mantle, which may trigger upwelling of hot mantle materials from the lower mantle to the shallow mantle beneath the subducting slabs and cause the slab-plume interactions. Some of these issues, such as the origin of intraplate magmatism, are still controversial, and so further detailed studies are needed from now.

Zhao, Dapeng; Yu, Sheng; Ohtani, Eiji

2011-02-01

243

Smithsonian Volcano Data on Google Earth  

NASA Astrophysics Data System (ADS)

Interactive global satellite imagery datasets such as hosted by Google Earth provide a dynamic platform for educational outreach in the Earth Sciences. Users with widely varied backgrounds can easily view geologic features on a global-to-local scale, giving access to educational background on individual geologic features or events such as volcanoes and earthquakes. The Smithsonian Institution's Global Volcanism Program (GVP) volcano data became available as a Google Earth layer on 11 June 2006. Locations for about 1550 volcanoes with known or possible Holocene activity are shown as red triangles with associated volcano names that appear when zooming in to a regional-scale view. Clicking on a triangle opens an informational balloon that displays a photo, geographic data, and a brief paragraph summarizing the volcano's geologic history. The balloon contains links to a larger version of the photo with credits and a caption and to more detailed information on the volcano, including eruption chronologies, from the GVP website. Links to USGS and international volcano observatories or other websites focusing on regional volcanoes are also provided, giving the user ready access to a broad spectrum of volcano data. Updates to the GVP volcano layer will be provided to Google Earth. A downloadable file with the volcanoes organized regionally is also available directly from the GVP website (www.volcano.si.edu) and provides the most current volcano data set. Limitations of the implied accuracy of spacially plotted data at high zoom levels are also apparent using platforms such as Google Earth. Real and apparent mismatches between plotted locations and the summits of some volcanoes seen in Google Earth satellite imagery occur for reasons including data precision (deg/min vs. deg/min/sec) and the GVP convention of plotting the center-point of large volcanic fields, which often do not correspond to specific volcanic vents. A more fundamental problem originates from the fact that regional topographic mapping does not utilize a standardized global datum, so that locations from topographic maps often diverge from those of the World Geodetic System datum used in geo-registered satellite imagery. These limitations notwithstanding, virtual globe platforms such as Google Earth provide an easily accessible pathway to volcano data for a broad spectrum of users ranging from the home/classroom to Earth scientists.

Venzke, E.; Siebert, L.; Luhr, J. F.

2006-12-01

244

Geoflicks Reviewed--Films about Hawaiian Volcanoes.  

ERIC Educational Resources Information Center

Reviews 11 films on volcanic eruptions in the United States. Films are given a one- to five-star rating and the film's year, length, source and price are listed. Top films include "Inside Hawaiian Volcanoes" and "Kilauea: Close up of an Active Volcano." (AIM)

Bykerk-Kauffman, Ann

1994-01-01

245

ASTER Images Mt. Usu Volcano  

NASA Technical Reports Server (NTRS)

On April 3, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra Satellite captured this image of the erupting Mt. Usu volcano in Hokkaido, Japan. 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 will image the Earth for the next 6 years to map and monitor the changing surface of our planet.

This false color infrared image of Mt Usu volcano is dominated by Lake Toya, an ancient volcanic caldera. On the south shore is the active Usu volcano. On Friday, March 31, more than 11,000 people were evacuated by helicopter, truck and boat from the foot of Usu, that began erupting from the northwest flank, shooting debris and plumes of smoke streaked with blue lightning thousands of feet in the air. Although no lava gushed from the mountain, rocks and ash continued to fall after the eruption. The region was shaken by thousands of tremors before the eruption. People said they could taste grit from the ash that was spewed as high as 2,700 meters (8,850 ft) into the sky and fell to coat surrounding towns with ash. 'Mount Usu has had seven significant eruptions that we know of, and at no time has it ended quickly with only a small scale eruption,' said Yoshio Katsui, a professor at Hokkaido University. This was the seventh major eruption of Mount Usu in the past 300 years. Fifty people died when the volcano erupted in 1822, its worst known eruption.

In the image, most of the land is covered by snow. Vegetation, appearing red in the false color composite, can be seen in the agricultural fields, and forests in the mountains. Mt. Usu is crossed by three dark streaks. These are the paths of ash deposits that rained out from eruption plumes two days earlier. The prevailing wind was from the northwest, carrying the ash away from the main city of Date. Ash deposited can be traced on the image as far away as 10 kilometers (16 miles) from the volcano.

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.

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 volcanoes; 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.

2000-01-01

246

Water in Aleutian Arc Volcanoes  

NASA Astrophysics Data System (ADS)

In the past decade, baseline data have been obtained on pre-eruptive water contents for several volcanic arcs worldwide. One surprising observation is that parental magmas contain ~ 4 wt% H2O on average at each arc worldwide [1]. Within each arc, the variation from volcano to volcano is from 2 to 6 w% H2O, with few exceptions. The similar averages at different arcs are unexpected given the order of magnitude variations in the concentration of other slab tracers. H2O is clearly different from other tracers, however, being both a major driver of melting in the mantle and a major control of buoyancy and viscosity in the crust. Some process, such as mantle melting or crustal storage, apparently modulates the water content of mafic magmas at arcs. Mantle melting may deliver a fairly uniform product to the Moho, if the wet melt process includes a negative feedback. On the other hand, magmas with variable water content may be generated in the mantle, but a crustal filter may lead to magma degassing up to a common mid-to-upper crustal storage region. Testing between these two end-member scenarios is critical to our understanding of subduction dehydration, global water budgets, magmatic plumbing systems, melt generation and eruptive potential. The Alaska-Aleutian arc is a prime location to explore this fundamental problem in the subduction water cycle, because active volcanoes vary more than elsewhere in the world in parental H2O contents (based on least-degassed, mafic melt inclusions hosted primarily in olivine). For example, Shishaldin volcano taps magma with among the lowest H2O contents globally (~ 2 wt%) and records low pressure crystal fractionation [2], consistent with a shallow magma system (< 1 km bsl). At the other extreme, Augustine volcano is fed by a mafic parent that contains among the highest H2O globally (~ 7 wt%), and has evolved by deep crystal fractionation [2], consistent with a deep magma system (~ 14 km bsl). Do these magmas stall at different depths because of different crustal regimes or because of different primary magma compositions? Do magmas degas until they physically stall, or do they stall when they start to degas? One test of this is whether H2O contents correlate with tracers from the subduction zone that are not fractionated easily during crystal fractionation or degassing. We find a strong negative correlation between H2O/Ce (based on the maximum H2O measured in a given inclusion population) and Nb/Ce in eight Aleutian volcanoes, which is well explained by variable amounts of a slab fluid, but would be fortuitous, or strongly disturbed, if major degassing took place in the crust during magma ascent. Thus, geochemical data point to a strong slab-mantle control on H2O, that may set the future course of magma ascent, storage and eruption. Integrated studies are needed to test this prediction, including seismic imaging and geodetic response of the volcanic system, from the slab to the surface. [1] Plank, et al. (2011) Min. Mag. 75: 1648. [2] Zimmer, et al. (2010) J. Pet. 51: 2411-2444.

Plank, T.; Zimmer, M. M.; Hauri, E. H.

2011-12-01

247

Volcano-tectonic structures and CO2-degassing patterns in the Laacher See basin, Germany  

NASA Astrophysics Data System (ADS)

The Laacher See Volcano is the youngest (12,900 year BP) eruption center of the Quarternary East-Eifel Volcanic Field in Germany and has formed Laacher See, the largest volcanic lake in the Eifel area. New bathymetric data of Laacher See were acquired by an echo sounder system and merged with topographic light detection and ranging (LiDAR) data of the Laacher See Volcano area to form an integrated digital elevation model. This model provides detailed morphological information about the volcano basin and results of sediment transport therein. Morphological analysis of Laacher See Volcano indicates a steep inner crater wall (slope up to 30°) which opens to the south. The Laacher See basin is divided into a deep northern and a shallower southern part. The broader lower slopes inclined with up to 25° change to the almost flat central part (maximum water depth of 51 m) with a narrow transition zone. Erosion processes of the crater wall result in deposition of volcaniclastics as large deltas in the lake basin. A large subaqueous slide was identified at the northeastern part of the lake. CO2-degassing vents (wet mofettes) of Laacher See were identified by a single-beam echo sounder system through gas bubbles in the water column. These are more frequent in the northern part of the lake, where wet mofettes spread in a nearly circular-shaped pattern, tracing the crater rim of the northern eruption center of the Laacher See Volcano. Additionally, preferential paths for gas efflux distributed concentrically inside the crater rim are possibly related to volcano-tectonic faults. In the southern part of Laacher See, CO2 vents occur in a high spatial density only within the center of the arc-shaped structure Barschbuckel possibly tracing the conduit of a tuff ring.

Goepel, Andreas; Lonschinski, Martin; Viereck, Lothar; Büchel, Georg; Kukowski, Nina

2014-12-01

248

Digital Data for Volcano Hazards in the Crater Lake Region, Oregon  

USGS Publications Warehouse

Crater Lake lies in a basin, or caldera, formed by collapse of the Cascade volcano known as Mount Mazama during a violent, climactic eruption about 7,700 years ago. This event dramatically changed the character of the volcano so that many potential types of future events have no precedent there. This potentially active volcanic center is contained within Crater Lake National Park, visited by 500,000 people per year, and is adjacent to the main transportation corridor east of the Cascade Range. Because a lake is now present within the most likely site of future volcanic activity, many of the hazards at Crater Lake are different from those at most other Cascade volcanoes. Also significant are many faults near Crater Lake that clearly have been active in the recent past. These faults, and historic seismicity, indicate that damaging earthquakes can occur there in the future. The USGS Open-File Report 97-487 (Bacon and others, 1997) describes the various types of volcano and earthquake hazards in the Crater Lake area, estimates of the likelihood of future events, recommendations for mitigation, and a map of hazard zones. The geographic information system (GIS) volcano hazard data layers used to produce the Crater Lake earthquake and volcano hazard map in USGS Open-File Report 97-487 are included in this data set. USGS scientists created one GIS data layer, c_faults, that delineates these faults and one layer, cballs, that depicts the downthrown side of the faults. Additional GIS layers chazline, chaz, and chazpoly were created to show 1)the extent of pumiceous pyroclastic-flow deposits of the caldera forming Mount Mazama eruption, 2)silicic and mafic vents in the Crater Lake region, and 3)the proximal hazard zone around the caldera rim, respectively.

Schilling, S.P.; Doelger, S.; Bacon, C.R.; Mastin, L.G.; Scott, K.E.; Nathenson, M.

2008-01-01

249

Volcano Flank Terraces on Mars  

NASA Astrophysics Data System (ADS)

Flank terraces are bulge-like structures that occur on the slopes of at least nine large shield volcanoes on Mars, and three on Earth. Terraces have a convex-upward, convex-outward morphology, with an imbricate "fish scale" stacking pattern in plan. They occur at all elevations, are scale-invariant structures, and have similar proportions to thrust faults on Earth. Suggested mechanisms of formation include elastic self-loading, lithospheric flexure, magma chamber tumescence, flank relaxation, and shallow gravitational slumping. Terrace geometries predicted by most of these mechanisms do not agree with our observations, however. Only lithospheric flexure can fully account for terrace geometry on Mars and Earth, and so is the most likely candidate mechanism for flank terrace formation. To verify this hypothesis, we conducted scaled analogue modelling experiments, and investigated the structures formed during flexure. Cones of a sand-gypsum mix were placed upon a deep layer of silicone gel, to simulate volcanic loads upon viscoelastic Martian crust. Key parameters were varied across our experimental program. In all cases convex topographic structures developed on the cones' flanks, arranged in an imbricate, overlapping plan-view pattern. These structures closely resemble flank terraces observed on Mars, and our results provide for a basic kinematic model of terrace formation. Analogue volcanoes experienced a decrease in upper surface area whilst volume was conserved; the contractional surface strain was accommodated by outward verging, circumferentially striking thrusts. The morphology of experimental structures suggests an orientation of the principal stress axes of ?1 = radial, ?2 = concentric, and ?3 = vertical. Elsewhere (J. B. Murray et al., this volume) we detail the relationship between flank terraces and other structures such as pit craters and gräben, using Ascraeus Mons as a case study. We suggest that terraces may influence the distribution and location of these other structures, and thus play a fundamental role in the tectonic development of large shield volcanoes on Mars.

Byrne, P. K.; van Wyk de Vries, B.; Murray, J. B.; Troll, V. R.

2008-12-01

250

Isotopic composition of gases from mud volcanoes  

SciTech Connect

A study has been made of the isotopic composition of the carbon in methane and carbon dioxide, as well as hydrogen in the methane, in the gases of mud volcanoes, for all main mud volcano areas in the USSR. The isotopic composition of carbon and hydrogen in methane shows that the gases resemble those of oil and gas deposits, while carbon dioxide of these volcanoes has a heavier isotopic composition with a greater presence of ''ultraheavy'' carbon dioxide. By the chemical and isotopic composition of gases, Azerbaidzhan and South Sakhalin types of mud volcano gases have been identified, as well as Bulganak subtypes and Akhtala and Kobystan varieties. Correlations are seen between the isotopic composition of gases and the geological build of mud volcano areas.

Valysaev, B.M.; Erokhin, V.E.; Grinchenko, Y.I.; Prokhorov, V.S.; Titkov, G.A.

1985-09-01

251

Volcanic gas impacts on vegetation at Turrialba Volcano, Costa Rica  

NASA Astrophysics Data System (ADS)

Turrialba volcano is an active composite stratovolcano that is located approximately 40 km east of San Jose, Costa Rica. Seismic activity and degassing have increased since 2005, and gas compositions reflect further increased activity since 2007 peaking in January 2010 with a phreatic eruption. Gas fumes dispersed by trade winds toward the west, northwest, and southwest flanks of Turrialba volcano have caused significant vegetation kill zones, in areas important to local agriculture, including dairy pastures and potato fields, wildlife and human populations. In addition to extensive vegetative degradation is the potential for soil and water contamination and soil erosion. Summit fumarole temperatures have been measured over 200 degrees C and gas emissions are dominated by SO2; gas and vapor plumes reach up to 2 km (fumaroles and gases are measured regularly by OVSICORI-UNA). A recent network of passive air sampling, monitoring of water temperatures of hydrothermal systems, and soil pH measurements coupled with measurement of the physiological status of surrounding plants using gas exchange and fluorescence measurements to: (1) identify physiological correlations between leaf-level gas exchange and chlorophyll fluorescence measurements of plants under long term stress induced by the volcanic gas emissions, and (2) use measurements in tandem with remotely sensed reflectance-derived fluorescence ratio indices to track natural photo inhibition caused by volcanic gas emissions, for use in monitoring plant stress and photosynthetic function. Results may prove helpful in developing potential land management strategies to maintain the biological health of the area.

Teasdale, R.; Jenkins, M.; Pushnik, J.; Houpis, J. L.; Brown, D. L.

2010-12-01

252

The "Plus Side" of Volcanoes  

NSDL National Science Digital Library

This web page provides a brief guide to the benefits of living with volcanoes. The topics considered are: Fertile Soils; Geothermal Energy with examples from Newberry Caldera in Oregon and in California, The Geysers, Casa Diablo in Long Valley Caldera, and the Salton Sea geothermal field; Mineral Resources including metallic minerals; Industrial Products including construction materials, cleaning agents, and raw materials for many chemical and industrial uses; Business Opportunities; Spas and Resorts; and Recreation and Tourism in America's national parks and monuments. Included among the parks are Yellowstone National Park, Mount Rainier National Park, and Mount St. Helens National Volcanic Monument.

253

Exploring Geology on the World-Wide Web--Volcanoes and Volcanism.  

ERIC Educational Resources Information Center

Focuses on sites on the World Wide Web that offer information about volcanoes. Web sites are classified into areas of Global Volcano Information, Volcanoes in Hawaii, Volcanoes in Alaska, Volcanoes in the Cascades, European and Icelandic Volcanoes, Extraterrestrial Volcanism, Volcanic Ash and Weather, and Volcano Resource Directories. Suggestions…

Schimmrich, Steven Henry; Gore, Pamela J. W.

1996-01-01

254

Seismic structure and origin of active intraplate volcanoes in Northeast Asia  

NASA Astrophysics Data System (ADS)

Three-dimensional P-wave velocity structure beneath the Changbai and other intraplate volcanic areas in Northeast Asia is determined by inverting 1378 high-quality P-wave arrival times from 186 teleseismic events recorded by 61 broadband seismic stations. Low-velocity (low-V) anomalies are revealed beneath the Changbai, Longgan, Xianjindao volcanoes. High-velocity (high-V) anomalies are found in the mantle transition zone, where deep-focus earthquakes under Hunchun occur at depths of 500-600 km. The high-V anomaly reflects the deep subduction of the Pacific slab under NE Asia which may have contributed to the formation of the Changbai, Longgang, Xianjindao and Jingpohu intraplate volcanoes. A low-V anomaly is also revealed in the mantle transition zone, which may have a close relationship with the occurrence of deep earthquakes under the Hunchun area. Our results support the Big Mantle Wedge (BMW) model by Zhao et al. [Zhao, D., Lei, J., Tang, Y., 2004. Origin of the Changbai volcano in northeast China: evidence from seismic tomography, Chin. Sci. Bull. 49, 1401-1408; Zhao, D., Maruyama, S., Omori, S., 2007. Mantle dynamics of western Pacific and East Asia: insight from seismic tomography and mineral physics. Gondwana Res. 11, 120-131.] who proposed that the intraplate volcanoes in NE Asia are caused by the back-arc magmatism associated with the deep dehydration process of the subducting slab and convective circulation process in the BMW above the stagnant Pacific slab.

Duan, Yonghong; Zhao, Dapeng; Zhang, Xiankang; Xia, Shaohong; Liu, Zhi; Wang, Fuyun; Li, Li

2009-05-01

255

Instrumentation Recommendations for Volcano Monitoring at U.S. Volcanoes Under the National Volcano Early Warning System  

USGS Publications Warehouse

As magma moves toward the surface, it interacts with anything in its path: hydrothermal systems, cooling magma bodies from previous eruptions, and (or) the surrounding 'country rock'. Magma also undergoes significant changes in its physical properties as pressure and temperature conditions change along its path. These interactions and changes lead to a range of geophysical and geochemical phenomena. The goal of volcano monitoring is to detect and correctly interpret such phenomena in order to provide early and accurate warnings of impending eruptions. Given the well-documented hazards posed by volcanoes to both ground-based populations (for example, Blong, 1984; Scott, 1989) and aviation (for example, Neal and others, 1997; Miller and Casadevall, 2000), volcano monitoring is critical for public safety and hazard mitigation. Only with adequate monitoring systems in place can volcano observatories provide accurate and timely forecasts and alerts of possible eruptive activity. At most U.S. volcanoes, observatories traditionally have employed a two-component approach to volcano monitoring: (1) install instrumentation sufficient to detect unrest at volcanic systems likely to erupt in the not-too-distant future; and (2) once unrest is detected, install any instrumentation needed for eruption prediction and monitoring. This reactive approach is problematic, however, for two reasons. 1. At many volcanoes, rapid installation of new ground-1. based instruments is difficult or impossible. Factors that complicate rapid response include (a) eruptions that are preceded by short (hours to days) precursory sequences of geophysical and (or) geochemical activity, as occurred at Mount Redoubt (Alaska) in 1989 (24 hours), Anatahan (Mariana Islands) in 2003 (6 hours), and Mount St. Helens (Washington) in 1980 and 2004 (7 and 8 days, respectively); (b) inclement weather conditions, which may prohibit installation of new equipment for days, weeks, or even months, particularly at midlatitude or high-latitude volcanoes; (c) safety factors during unrest, which can limit where new instrumentation can safely be installed (particularly at near-vent sites that can be critical for precursor detection and eruption forecasting); and (d) the remoteness of many U.S. volcanoes (particularly those in the Aleutians and the Marianas Islands), where access is difficult or impossible most of the year. Given these difficulties, it is reasonable to anticipate that ground-based monitoring of eruptions at U.S. volcanoes will likely be performed primarily with instruments installed before unrest begins. 2. Given a growing awareness of previously undetected 2. phenomena that may occur before an eruption begins, at present the types and (or) density of instruments in use at most U.S. volcanoes is insufficient to provide reliable early warning of volcanic eruptions. As shown by the gap analysis of Ewert and others (2005), a number of U.S. volcanoes lack even rudimentary monitoring. At those volcanic systems with monitoring instrumentation in place, only a few types of phenomena can be tracked in near-real time, principally changes in seismicity, deformation, and large-scale changes in thermal flux (through satellite-based remote sensing). Furthermore, researchers employing technologically advanced instrumentation at volcanoes around the world starting in the 1990s have shown that subtle and previously undetectable phenomena can precede or accompany eruptions. Detection of such phenomena would greatly improve the ability of U.S. volcano observatories to provide accurate early warnings of impending eruptions, and is a critical capability particularly at the very high-threat volcanoes identified by Ewert and others (2005). For these two reasons, change from a reactive to a proactive volcano-monitoring strategy is clearly needed at U.S. volcanoes. Monitoring capabilities need to be expanded at virtually every volcanic center, regardless of its current state of

Moran, Seth C.; Freymueller, Jeff T.; LaHusen, Richard G.; McGee, Kenneth A.; Poland, Michael P.; Power, John A.; Schmidt, David A.; Schneider, David J.; Stephens, George; Werner, Cynthia A.; White, Randall A.

2008-01-01

256

Precursory Seismic Activity at Guagua Pichincha Volcano, Ecuador: Implications for the Magmatic System of an Arc Volcano  

Microsoft Academic Search

Earthquake activity at volcanoes can offer insight into the nature of the transport and storage of magma beneath active volcanoes. Understanding the relation between volcano seismicity and the magmatic system is important in long and short-term forecasting of volcanic activity. Guagua Pichincha, a dacitic volcano located in the western cordillera of the Ecuadorian Andes, showed two years of progressive reactivation

D. R. Villagomez; M. Ruiz; H. Yepes; M. L. Hall

2003-01-01

257

Igneous rocks of the East Pacific Rise  

USGS Publications Warehouse

The apical parts of large volcanoes along the East Pacific Rise (islands and seamounts) are encrusted with rocks of the alkali volcanic suite (alkali basalt, andesine- and oligoclase-andesite, and trachyte). In contrast, the more submerged parts of the Rise are largely composed of a tholeiitic basalt which has low concentrations of K, P, U, Th, Pb, and Ti. This tholeiitic basalt is either the predominant or the only magma generated in the earth's mantle under oceanic ridges and rises. It is at least 1000-fold more abundant than the alkali suite, which is probably derived from tholeiitic basalt by magmatic differentiation in and immediately below the larger volcanoes. Distinction of oceanic tholeiites from almost all continental tholeiites is possible on the simple basis of total potassium content, with the discontinuity at 0.3 to 0.5 percent K2O by weight. Oceanic tholeiites also are readily distinguished from some 19 out of 20 basalts of oceanic islands and seamount cappings by having less than 0.3 percent K2O by weight and more than 48 percent SiO2. Deep drilling into oceanic volcanoes should, however, core basalts transitional between the oceanic tholeiites and the presumed derivative alkali basalts.The composition of the oceanic tholeiites suggests that the mantle under the East Pacific Rise contains less than 0.10 percent potassium oxide by weight; 0.1 part per million of uranium and 0.4 part of thorium; a potassium:rubidium ratio of about 1200 and a potassium: uranium ratio of about 104.

Engel, A.E.J.; Engel, C.G.

1964-01-01

258

Role of the structural inheritance of the oceanic lithosphere in the magmato-tectonic evolution of Piton de la Fournaise volcano (La Réunion Island)  

Microsoft Academic Search

La Réunion Island is located east of Madagascar, on the eastern rim of the tectonically inactive Mascarene Basin. This island is composed of three shield volcanoes of which only Piton de la Fournaise is currently active. Although the magmatic activity is restricted to Piton de la Fournaise, a scattered seismicity occurs on the whole 200 km wide volcanic edifice and

Laurent Michon; Francky Saint-Ange; Patrick Bachelery; Nicolas Villeneuve; Thomas Staudacher

2007-01-01

259

Eruption of Shiveluch Volcano, Kamchatka Peninsula  

NASA Technical Reports Server (NTRS)

On March 29, 2007, the Shiveluch Volcano on the Russian Federation's Kamchatka Peninsula erupted. According to the Alaska Volcano Observatory the volcano underwent an explosive eruption between 01:50 and 2:30 UTC, sending an ash cloud skyward roughly 9,750 meters (32,000 feet), based on visual estimates. The Moderate Resolution Imaging Spectroradiometer (MODIS) flying onboard NASA's Aqua satellite took this picture at 02:00 UTC on March 29. The top image shows the volcano and its surroundings. The bottom image shows a close-up view of the volcano at 250 meters per pixel. Satellites often capture images of volcanic ash plumes, but usually as the plumes are blowing away. Plumes have been observed blowing away from Shiveluch before. This image, however, is different. At the time the Aqua satellite passed overhead, the eruption was recent enough (and the air was apparently still enough) that the ash cloud still hovered above the summit. In this image, the bulbous cloud casts its shadow northward over the icy landscape. Volcanic ash eruptions inject particles into Earth's atmosphere. Substantial eruptions of light-reflecting particles can reduce temperatures and even affect atmospheric circulation. Large eruptions impact climate patterns for years. A massive eruption of the Tambora Volcano in Indonesia in 1815, for instance, earned 1816 the nickname 'the year without a summer.' Shiveluch is a stratovolcano--a steep-sloped volcano composed of alternating layers of solidified ash, hardened lava, and volcanic rocks. One of Kamchatka's largest volcanoes, it sports a summit reaching 3,283 meters (10,771 feet). Shiveluch is also one of the peninsula's most active volcanoes, with an estimated 60 substantial eruptions in the past 10,000 years.

2007-01-01

260

Intraplate volcanism and mantle dynamics in East Asia: Big mantle wedge (BMW) model (Invited)  

NASA Astrophysics Data System (ADS)

In the East Asia continent there are many Cenozoic volcanoes, but only a few are still active now, such as the Changbai, Wudalianchi, and Tengchong volcanoes which have erupted several times in the past 1000 years. Although many studies have been made by using various approaches, the origin of the intraplate volcanoes in East Asia is still not very clear. Recently we used regional and global seismic tomography to determine high-resolution 3-D mantle structure under Western Pacific to East Asia (Zhao, 2004; Huang and Zhao, 2006; Zhao et al., 2009). Our results show prominent low-velocity anomalies from the surface down to 410 km depth beneath the intraplate volcanoes and a broad high-velocity anomaly in the mantle transition zone under East Asia. Focal-mechanism solutions of deep earthquakes indicate that the subducting Pacific slab under the Japan Sea and the East Asia margin is subject to compressive stress regime. These results suggest that the Pacific slab meets strong resistance at the 660-km discontinuity and so it becomes stagnant in the mantle transition zone under East Asia. The Philippine Sea slab has also subducted down to the mantle transition zone under western Japan and the Ryukyu back-arc region. The western edge of the stagnant slab is generally parallel with the Japan trench and the Ryukyu trench and roughly coincides with a prominent surface topography and gravity boundary in East China, which is located approximately 1800 km west of the trenches. The upper mantle under East Asia has formed a big mantle wedge (BMW) above the stagnant slab. The BMW exhibits low seismic-velocity and high electrical-conductivity, which is hot and wet because of the deep dehydration reactions of the stagnant slab and the convective circulation process in the BMW. These processes lead to the upwelling of hot and wet asthenospheric materials and thinning and fracturing of the continental lithosphere, leading to the formation of the active intraplate volcanoes in East Asia. Our results also show that the active Tengchong volcano in SW China is related to the deep subduction of the Burma microplate down to the mantle transition zone and a BMW above the Burma slab. References: D. Zhao (2004) Phys. Earth Planet. Inter. 146, 3-34. J. Huang, D. Zhao (2006) J. Geophys. Res. 111, B09305. D. Zhao et al. (2009) Phys. Earth Planet. Inter. 173, 197-206.

Zhao, D.

2009-12-01

261

Volcanoes  

MedlinePLUS

... is a vent in the Earth's crust. Hot rock, steam, poisonous gases, and ash reach the Earth's ... can also cause earthquakes, mudflows and flash floods, rock falls and landslides, acid rain, fires, and even ...

262

Volcanoes  

MedlinePLUS

... of molten rock below the surface of the earth. Unlike most mountains, which are pushed up from ... vents through which molten rock escapes to the earth’s surface. When pressure from gases within the molten ...

263

2005 Volcanic Activity in Alaska, Kamchatka, and the Kurile Islands: Summary of Events and Response of the Alaska Volcano Observatory  

USGS Publications Warehouse

The Alaska Volcano Observatory (AVO) responded to eruptive activity or suspected volcanic activity at or near 16 volcanoes in Alaska during 2005, including the high profile precursory activity associated with the 2005?06 eruption of Augustine Volcano. AVO continues to participate in distributing information about eruptive activity on the Kamchatka Peninsula, Russia, and in the Kurile Islands of the Russian Far East, in conjunction with the Kamchatkan Volcanic Eruption Response Team (KVERT) and the Sakhalin Volcanic Eruption Response Team (SVERT), respectively. In 2005, AVO helped broadcast alerts about activity at 8 Russian volcanoes. The most serious hazard posed from volcanic eruptions in Alaska, Kamchatka, or the Kurile Islands is the placement of ash into the atmosphere at altitudes traversed by jet aircraft along the North Pacific and Russian Trans East air routes. AVO, KVERT, and SVERT work collaboratively with the National Weather Service, Federal Aviation Administration, and the Volcanic Ash Advisory Centers to provide timely warnings of volcanic eruptions and the production and movement of ash clouds.

McGimsey, R.G.; Neal, C.A.; Dixon, J.P.; Ushakov, Sergey

2008-01-01

264

How Volcanoes Work: Historical Eruptions  

NSDL National Science Digital Library

This information about major volcanic eruptions in history covers events from the civilization-destroying explosion at Santorini in about 1630 BC, to the killing cloud of carbon dioxide at Lake Nyos Cameroon in 1986. The site documents the seven deadliest eruptions in history. Other eruptions include Mount Pelee on the island of Martinique in 1902, Mount Saint Helens in Washington State in 1980, Nevado Del Ruiz Columbia in 1985, the Mexican eruption of Paricutin in 1943, and the 1883 explosion that nearly obliterated the island of Krakatau in what is now Indonesia. For each eruption the site offers information about the type of volcano, the type of eruption, the products of the eruption, and the relation to plate tectonics. In addition, historical background is provided when appropriate.

Victor Camp

265

Volcanoes can muddle the greenhouse  

SciTech Connect

As scientists and politicians anxiously eye signs of global greenhouse warming, climatologists are finding the best evidence yet that a massive volcanic eruption can temporarily bring the temperature down a notch or two. Such a cooling could be enough to set the current global warming back more than a decade, confusing any efforts to link it to the greenhouse effect. By effectively eliminating some nonvolcanic climate changes from the record of the past 100 years, researchers have detected drops in global temperature of several tenths of a degree within 1 to 2 years of volcanic eruptions. Apparently, the debris spewed into the stratosphere blocked sunlight and caused the temperature drops. For all their potential social significance, the climate effects of volcanoes have been hard to detect. The problem has been in identifying a volcanic cooling among the nearly continuous climate warmings and coolings of a similar size that fill the record. The paper reviews how this was done.

Kerr, R.A.

1990-01-01

266

Gravity fluctuations induced by magma convection at Kilauea Volcano, Hawai'i  

USGS Publications Warehouse

Convection in magma chambers is thought to play a key role in the activity of persistently active volcanoes, but has only been inferred indirectly from geochemical observations or simulated numerically. Continuous microgravity measurements, which track changes in subsurface mass distribution over time, provide a potential method for characterizing convection in magma reservoirs. We recorded gravity oscillations with a period of ~150 s at two continuous gravity stations at the summit of K?lauea Volcano, Hawai‘i. The oscillations are not related to inertial accelerations caused by seismic activity, but instead indicate variations in subsurface mass. Source modeling suggests that the oscillations are caused by density inversions in a magma reservoir located ~1 km beneath the east margin of Halema‘uma‘u Crater in K?lauea Caldera—a location of known magma storage.

Carbone, Daniele; Poland, Michael P.

2012-01-01

267

Newberry Volcano—Central Oregon's Sleeping Giant  

USGS Publications Warehouse

Hidden in plain sight, Oregon's massive Newberry Volcano is the largest volcano in the Cascades volcanic arc and covers an area the size of Rhode Island. Unlike familiar cone-shaped Cascades volcanoes, Newberry was built into the shape of a broad shield by repeated eruptions over 400,000 years. About 75,000 years ago a major explosion and collapse event created a large volcanic depression (caldera) at its summit. Newberry last erupted about 1,300 years ago, and present-day hot springs and geologically young lava flows indicate that it could reawaken at any time. Because of its proximity to nearby communities, frequency and size of past eruptions, and geologic youthfulness, U.S. Geological Survey scientists are working to better understand volcanic activity at Newberry and closely monitor the volcano for signs of unrest.

Donnelly-Nolan, Julie M.; Stovall, Wendy K.; Ramsey, David W.; Ewert, John W.; Jensen, Robert A.

2011-01-01

268

Lahar hazards at Agua volcano, Guatemala  

USGS Publications Warehouse

At 3760 m, Agua volcano towers more than 3500 m above the Pacific coastal plain to the south and 2000 m above the Guatemalan highlands to the north. The volcano is within 5 to 10 kilometers (km) of Antigua, Guatemala and several other large towns situated on its northern apron. These towns have a combined population of nearly 100,000. It is within about 20 km of Escuintla (population, ca. 100,000) to the south. Though the volcano has not been active in historical time, or about the last 500 years, it has the potential to produce debris flows (watery flows of mud, rock, and debris—also known as lahars when they occur on a volcano) that could inundate these nearby populated areas.

Schilling, S.P.; Vallance, J.W.; Matías, O.; Howell, M.M.

2001-01-01

269

Publications of the Volcano Hazards Program 2005  

E-print Network

Fairbanks MS thesis, 139 p., available at http://www.avo.alaska.edu/downloads/ Bacon, C. R., and Lowenstern., Larsen, J. F., Neal, C. A., Nye, C. J., and Schaefer, J. R., 2005, Preliminary volcano- hazard assessment

Torgersen, Christian

270

Natural Resources Canada: Volcanoes of Canada  

NSDL National Science Digital Library

Natural Resources Canada has launched yet another impressive and educational Web site. At this site you can learn all you wanted to know about Canadian volcanoes and volcanology. The site offers an introduction to volcanoes, in-depth sections on types, eruptions, hazards, and risks. You can also discover interesting facts, such as how eruptions in Alaska and the Western coast of the US impact agriculture and air travel in Canada. In addition to text, the site offers a wonderful interactive Map of Canadian Volcanoes. The Catalogue of Canadian Volcanoes is also an excellent reference tool. Available in English and French, this site is easy to understand and ideal for science students as well as anyone interested in volcanology. This site is also reviewed in the August 22, 2003 NSDL Physical Sciences Report.

271

Eruption of Alaska volcano breaks historic pattern  

USGS Publications Warehouse

In the late morning of 12 July 2008, the Alaska Volcano Observatory (AVO) received an unexpected call from the U.S. Coast Guard, reporting an explosive volcanic eruption in the central Aleutians in the vicinity of Okmok volcano, a relatively young (~2000-year-old) caldera. The Coast Guard had received an emergency call requesting assistance from a family living at a cattle ranch on the flanks of the volcano, who reported loud "thunder," lightning, and noontime darkness due to ashfall. AVO staff immediately confirmed the report by observing a strong eruption signal recorded on the Okmok seismic network and the presence of a large dark ash cloud above Okmok in satellite imagery. Within 5 minutes of the call, AVO declared the volcano at aviation code red, signifying that a highly explosive, ash-rich eruption was under way.

Larsen, Jessica; Neal, Christina; Webley, Peter; Freymueller, Jeff; Haney, Matthew; McNutt, Stephen; Schneider, David; Prejean, Stephanie; Schaefer, Janet; Wessels, Rick

2009-01-01

272

Hydrogeochemical exploration of the Tecuamburro Volcano region, Guatemala  

SciTech Connect

Approximately 100 thermal and nonthermal water samples and 20 gas samples from springs and fumaroles have been chemically and isotopically analyzed to help evaluate the geothermal potential of the Tecuamburro Volcano region, Guatemala. Thermal waters of the acid- sulfate, steam condensate, and neutral-chloride types generally occur in restricted hydrogeologic areas: Tecuamburro-Laguna Ixpaco (acid- sulfate); andesite highland north of Tecuamburro (steam-condensate); Rio Los Esclavos (neutral-chloride). One small area of neutral-chloride springs east of the village of Los Esclavos has no relation to the Tecuamburro geothermal system. Neutral-chloride springs on the Rio Los Esclavos east and southeast of Tecuamburro show mixing with various types of groundwaters and display a maximum oxygen-18 enrichment compared to the world meteoric line of only about 1.5 parts per thousand. Maximum estimated subsurface temperatures are {le}200{degree}C. In contrast, maximum estimated subsurface temperatures based on gas compositions in the Laguna Ixpaco area are about 300{degree}C. The relation of neutral-chloride waters to the overall Tecuamburro geothermal system is not entirely resolved but we have suggested two system models. Regardless of model, we believe that a first exploration drill hole should be sited within 0.5 km of Laguna Ixpaco to tap the main geothermal reservoir or its adjacent, main upflow zone. 9 refs., 4 figs., 3 tabs.

Goff, F.; Truesdell, A.H.; Janik, C.J.; Adams, A.; Roldan-M, A.; Meeker, K. (Los Alamos National Lab., NM (USA); Geological Survey, Menlo Park, CA (USA); Los Alamos National Lab., NM (USA); Instituto Nacional de Electrificacion, Guatemala City (Guatemala). Unidad de Desarollo Geotermico; Los Alamos National Lab., NM (USA))

1989-01-01

273

Diversity and Spatial Distribution of Prokaryotic Communities Along A Sediment Vertical Profile of A Deep-Sea Mud Volcano  

Microsoft Academic Search

We investigated the top 30-cm sediment prokaryotic community structure in 5-cm spatial resolution, at an active site of the\\u000a Amsterdam mud volcano, East Mediterranean Sea, based on the 16S rRNA gene diversity. A total of 339 and 526 sequences were\\u000a retrieved, corresponding to 25 and 213 unique (?98% similarity) phylotypes of Archaea and Bacteria, respectively, in all depths.\\u000a The Shannon–Wiener

Maria G. Pachiadaki; Argyri Kallionaki; Anke Dählmann; Gert J. De Lange; Konstantinos Ar. Kormas

274

Evolution of large shield volcanoes on Venus  

NASA Technical Reports Server (NTRS)

We studied the geologic history, topographic expression, and gravity signature of 29 large Venusian shield volcanoes with similar morphologies in Magellan synthetic aperture radar imagery. While they appear similar in imagery, 16 have a domical topographic expression and 13 have a central depression. Typical dimensions for the central depression are 150 km wide and 500 m deep. The central depressions are probably not calderas resulting from collapse of a shallow magma chamber but instead are the result of a corona-like sagging of a previously domical volcano. The depressions all have some later volcanic filling. All but one of the central depression volcanoes have been post-dated by geologic features unrelated to the volcano, while most of the domical volcanoes are at the top of the stratigraphic column. Analysis of the gravity signatures in the spatial and spectral domains shows a strong correlation between the absence of post-dating features and the presence of dynamic support by an underlying plume. We infer that the formation of the central depressions occurred as a result of cessation of dynamic support. However, there are some domical volcanoes whose geologic histories and gravity signatures also indicate that they are extinct, so sagging of the central region apparently does not always occur when dynamic support is removed. We suggest that the thickness of the elastic lithosphere may be a factor in determining whether a central depression forms when dynamic support is removed, but the gravity data are of insufficient resolution to test this hypothesis with admittance methods.

Herrick, Robert R.; Dufek, Josef; McGovern, Patrick J.

2005-01-01

275

Pre-, Syn- and Post Eruptive Seismicity of the 2011 Eruption of Nabro Volcano, Eritrea  

NASA Astrophysics Data System (ADS)

Nabro volcano, located in south-east Eritrea, East Africa, lies at the eastern margin of the Afar Rift and the Danakil Depression. Its tectonic behaviour is controlled by the divergence of the Arabian, Nubian and Somali plates. Nabro volcano was thought to be seismically quiet until it erupted in June 2011 with limited warning. The volcano erupted on June 12, 2011 around 20:32 UTC, following a series of earthquakes on that day that reached a maximum magnitude of 5.8. It is the first recorded eruption of Nabro volcano and only the second in Eritrea, following the Dubbi eruption in 1861. A lava flow emerged from the caldera and travelled about 20 km from the vent and buried settlements in the area. At the time of this eruption there was no seismic network in Eritrea, and hence the volcano was not monitored. In this study we use ten Ethiopian, one Yemeni and one Djibouti stations to investigate the seismicity of the area before, during and after the eruption. Four Eritrean seismic stations deployed in June 2011, four days after the eruption, are also included in the dataset. Travel time picks supplied by colleagues from Djibouti were also incorporated into the dataset. Our analysis covers roughly three months before and after the eruption and shows that Nabro was seismically quiet before the eruption (nine events), with the exception of one major earthquake (4.8 magnitude) that occurred on March 31, 2011. In contrast, the region shows continued seismic activity after the eruption (92 events). During the eruption seismicity levels are high (123 events), with two days particularly active, June 12 and June 17 with 85 and 28 discrete events, respectively. Maximum magnitudes of 5.8 and 5.9 were recorded on these two days. The two days of increased seismicity are consistent with satellite observations of the eruption which show two distinct phases of the eruption. The period between these two phases was dominated by volcanic tremor. The tremor signal lasted for almost one month following the initiation of the eruption. In summary, we have shown that the volcano was relatively quiet before eruption but continued to be seismically active for an extended period of time afterwards.

Goitom, Berhe; Hammond, James; Kendall, Michael; Nowacky, Andy; Keir, Derek; Oppenheimer, Clive; Ogubazghi, Ghebrebrhan; Ayele, Atalay; Ibrahim, Said; Jacques, Eric

2014-05-01

276

Latest Isopach Mapping of Holocene Rhyolitic Tephras at Medicine Lake Volcano, Northern California  

NASA Astrophysics Data System (ADS)

Medicine Lake Volcano, located in the southern Cascades ~55 km east-northeast of Mount Shasta, is a large rear-arc, shield-shaped volcano with an eruptive history spanning nearly 500,000 years. The most recent eruptions at Medicine Lake Volcano are the late Holocene explosive to effusive events at Glass Mountain (~950 yr) and Little Glass Mountain (~1000 yr), which began as sub-Plinian to Plinian eruptions of rhyolite pumice from fissure vents, and culminated in the rhyolite-dacite of Glass Mountain and the rhyolite of Little Glass Mountain. Vents for these eruptions lie along fissures located 15 km apart on opposite sides of the summit caldera of Medicine Lake Volcano. Previous mapping of these deposits by Fisher (1964) and by Heiken (1978) showed a strong northeast-southwest trend of the Little Glass Mountain tephras. Our latest isopach maps of primary tephra deposits from the Glass Mountain and Little Glass Mountain eruptions are based on more extensive fieldwork and on a different interpretation of Little Glass Mountain tephras than previous work Our work shows a strong northeast-southwest trend of the Little Glass Mountain tephras and extends the deposit further in the direction of Mount Shasta, where C. D. Miller found individual lapilli from the Little Glass Mountain eruption. This plume direction is unusual given the dominant westerly wind directions in the region. Winds blow from the northeast less than 2 percent of the time in a typical year. Our field investigations have also shown that Little Glass Mountain tephras consist of two distinct deposits: a coarse, white, pumiceous deposit erupted from Little Glass Mountain and found along the strong northeast-southwest trend; and a fine-grained, salmon-colored tephra erupted from fissure vents north of Little Glass Mountain around Crater Glass Flow and found to the north and east. Field relationships show that the salmon-colored tephra was erupted just prior to the white, pumiceous tephra, and that its fine grain size may be due to magma interaction with shallow groundwater during eruption. Glass Mountain tephra deposits do not exhibit strong distribution trends, but rather are found in lobes extending from the fissure vents to the west, northeast, and east, reflecting the dominant regional wind directions. Our mapping extends and refines the primary tephra deposits from Glass Mountain as they decend on the arid eastern flanks of Medicine Lake Volcano and become extensively reworked by wind. As rhyolite eruptions in the Cascade Range are quite rare, mapping the thickness, extent, and character of these tephra deposits to better comprehend the dynamics of these eruptions is important for understanding future events and the hazards they may pose.

Ramsey, D. W.; Miller, C. D.

2011-12-01

277

Volcano-earthquake interaction at Mauna Loa volcano, Hawaii Thomas R. Walter1,2  

E-print Network

Volcano-earthquake interaction at Mauna Loa volcano, Hawaii Thomas R. Walter1,2 and Falk Amelung1 into the Southwest Rift Zone (SWRZ) or into the Northeast Rift Zone (NERZ) and by large earthquakes at the basal decollement fault. In this paper we examine the historic eruption and earthquake catalogues, and we test

Amelung, Falk

278

An Admittance Survey of Large Volcanoes on Venus: Implications for Volcano Growth  

NASA Technical Reports Server (NTRS)

Estimates of the thickness of the venusian crust and elastic lithosphere are important in determining the rheological and thermal properties of Venus. These estimates offer insights into what conditions are needed for certain features, such as large volcanoes and coronae, to form. Lithospheric properties for much of the large volcano population on Venus are not well known. Previous studies of elastic thickness (Te) have concentrated on individual or small groups of edifices, or have used volcano models and fixed values of Te to match with observations of volcano morphologies. In addition, previous studies use different methods to estimate lithospheric parameters meaning it is difficult to compare their results. Following recent global studies of the admittance signatures exhibited by the venusian corona population, we performed a similar survey into large volcanoes in an effort to determine the range of lithospheric parameters shown by these features. This survey of the entire large volcano population used the same method throughout so that all estimates could be directly compared. By analysing a large number of edifices and comparing our results to observations of their morphology and models of volcano formation, we can help determine the controlling parameters that govern volcano growth on Venus.

Brian, A. W.; Smrekar, S. E.; Stofan, E. R.

2004-01-01

279

The changing shapes of active volcanoes: History, evolution, and future challenges for volcano geodesy  

E-print Network

geodesy Michael Poland a,*, Michael Hamburger b,1 , Andrew Newman c,2 a U.S. Geological Survey, Hawaiian of modern research in volcanology. The field of volcano geodesy is uniquely situated to provide critical a proper context for these stud- ies, we offer a short review of the evolution of volcano geodesy, as well

280

Coda wave interferometry and correlation study using multiplets in the Katla volcano, 2011 and 2012  

NASA Astrophysics Data System (ADS)

The Katla volcano, a glacier overlain hyaloclastite massive in S-Iceland, is one of the most active and hazardous volcanoes in Iceland. Its ice filled oval caldera, 9x14 km in diameter, forms a glacier plateau surrounded by higher rims. The glacier surface is marked with about a dozen circular depressions or cauldrons, manifestations of shallow geothermal activity. Katla eruptions are usually accompanied by intense tephra fall and hazardous glacial floods, jökulhlaups. Since year 1179, there are 17 documented eruptions, on average every decennia (±40 years), the last one being in 1918. Thus, the Katla volcano is being closely watched. The SIL seismic catalogue for 2011 and 2012 includes over 4000 events within the Katla volcano. By far the most events occur in the steep western part of the glacier and have been shown to be caused by shallow glacial processes. These events are easily recognized in the data due to their low frequency content (0.5-2 hz) and long surface wave coda. The second most common events are found around the glacial cauldrons and seem to be caused by very shallow processes probably involving glacial deformation and changes in the geothermal activity. Tectonic events within the massive are not as common. In fact, the low rate of tectonic events recorded in Katla during the past two years, as well as their small size (volcano is low. However, considering the volcano's repose interval and the impending threat we focus on the latest data and methods that are capable of finding even the smallest changes within the volcano. One such method is the coda wave interferometry technique. The method is based on the fact that changes in stress in the edifice lead to changes in seismic velocities. Hence continuous monitoring of these changes is desirable in the pre-eruptive phase. Coda waves are multiply scattered in the medium and are very sensitive to small changes. For repeating or multiplet earthquake source (same source, same path) small time shifts in the arrival times of wavelets in the coda can be used to track temporal variations in velocity through coda wave interferometry analysis. The glacial seismicity in the western part offers a set of multiplets with magnitudes M0.5-2.5. Although these events have a strong seasonal tendency, they do occur throughout the year. We present a coda wave interferometry study using the glacial multiplets. Their seismic rays, originating in the western flank of the volcano, penetrate down to around 5 km depth beneath the volcano when recorded at a roughly 30 km distance at several stations east of the volcano and even (at a closer distance, and with shallower penetration) south and north of the volcano.

Jonsdottir, Kristin; Vogfjord, Kristin; Bean, Chris

2013-04-01

281

Radar observations of the 2009 eruption of Redoubt Volcano, Alaska: Initial deployment of a transportable Doppler radar system for volcano-monitoring  

NASA Astrophysics Data System (ADS)

The rapid detection of explosive volcanic eruptions and accurate determination of eruption-column altitude and ash-cloud movement are critical factors in the mitigation of volcanic risks to aviation and in the forecasting of ash fall on nearby communities. The U.S. Geological Survey (USGS) deployed a transportable Doppler radar during the precursory stage of the 2009 eruption of Redoubt Volcano, Alaska, and it provided valuable information during subsequent explosive events. We describe the capabilities of this new monitoring tool and present data that it captured during the Redoubt eruption. The volcano-monitoring Doppler radar operates in the C-band (5.36 cm) and has a 2.4-m parabolic antenna with a beam width of 1.6 degrees, a transmitter power of 330 watts, and a maximum effective range of 240 km. The entire disassembled system, including a radome, fits inside a 6-m-long steel shipping container that has been modified to serve as base for the antenna/radome, and as a field station for observers and other monitoring equipment. The radar was installed at the Kenai Municipal Airport, 82 km east of Redoubt and about 100 km southwest of Anchorage. In addition to an unobstructed view of the volcano, this secure site offered the support of the airport staff and the City of Kenai. A further advantage was the proximity of a NEXRAD Doppler radar operated by the Federal Aviation Administration. This permitted comparisons with an established weather-monitoring radar system. The new radar system first became functional on March 20, roughly a day before the first of nineteen explosive ash-producing events of Redoubt between March 21 and April 4. Despite inevitable start-up problems, nearly all of the events were observed by the radar, which was remotely operated from the Alaska Volcano Observatory office in Anchorage. The USGS and NEXRAD radars both detected the eruption columns and tracked the directions of drifting ash clouds. The USGS radar scanned a 45-degree sector centered on the volcano while NEXRAD scanned a full 360 degrees. The sector strategy scanned the volcano more frequently than the 360-degree strategy. Consequently, the USGS system detected event onset within less than a minute, while the NEXRAD required about 4 minutes. The observed column heights were as high as 20 km above sea level and compared favorably to those from NEXRAD. NEXRAD tracked ash clouds to greater distances than the USGS system. This experience shows that Doppler radar is a valuable complement to traditional seismic and satellite monitoring of explosive eruptions.

Hoblitt, R. P.; Schneider, D. J.

2009-12-01

282

Nyiragongo Volcano before the Eruption  

NASA Technical Reports Server (NTRS)

Nyiragongo is an active stratovolcano situated on the Eastern African Rift; it is part of Africa's Virunga Volcanic Chain. In a massive eruption that occurred on January 17, 2002, Nyiragongo sent a vast plume of smoke and ash skyward, and three swifly-moving rivers of lava streaming down its western and eastern flanks. Previous lava flows from Nyiragongo have been observed moving at speeds of up to 40 miles per hour (60 kph). The lava flows from the January 17 eruption destroyed more than 14 villages in the surrounding countryside, forcing tens of thousands to flee into the neighboring country of Rwanda. Within one day the lava ran to the city of Goma, situated on the northern shore of Lake Kivu about 12 miles (19 km) south of Nyiragongo. The lava cut a 200 foot (60 meter) wide swath right through Goma, setting off many fires, as it ran into Lake Kivu. Goma, the most heavily populated city in eastern Democratic Republic of Congo, is home to about 400,000 people. Most of these citizens were forced to flee, while many have begun to return to their homes only to find their homes destroyed. This true-color scene was captured by the Enhanced Thematic Mapper Plus (ETM+), flying aboard the Landsat 7 satellite, on December 11, 2001, just over a month before the most recent eruption. Nyiragongo's large crater is clearly visible in the image. As recently as June 1994, there was a large lava lake in the volcano's crater which had since solidified. The larger Nyamuragira Volcano is located roughly 13 miles (21 km) to the north of Nyiragongo. Nyamuragira last erupted in February and March 2001. That eruption was also marked by columns of erupted ash and long fluid lava flows, some of which are apparent in the image as dark greyish swaths radiating away from Nyamuragira. Both peaks are also notorious for releasing large amounts of sulfur dioxide, which presents another health hazard to people and animals living in close proximity. Image by Robert Simmon, based on data supplied by the NASA GSFC Landsat 7 Science Team

2002-01-01

283

Update of map the volcanic hazard in the Ceboruco volcano, Nayarit, Mexico  

NASA Astrophysics Data System (ADS)

The Ceboruco Volcano (21° 7.688 N, 104° 30.773 W) is located in the northwestern part of the Tepic-Zacoalco graben. Its volcanic activity can be divided in four eruptive cycles differentiated by their VEI and chemical variations as well. As a result of andesitic effusive activity, the "paleo-Ceboruco" edifice was constructed during the first cycle. The end of this cycle is defined by a plinian eruption (VEI between 3 and 4) which occurred some 1020 years ago and formed the external caldera. During the second cycle an andesitic dome built up in the interior of the caldera. The dome collapsed and formed the internal caldera. The third cycle is represented by andesitic lava flows which partially cover the northern and south-southwestern part of the edifice. The last cycle is represented by the andesitic lava flows of the nineteenth century located in the southwestern flank of the volcano. Actually, moderate fumarolic activity occurs in the upper part of the volcano showing temperatures ranging between 20° and 120°C. Some volcanic high frequency tremors have also been registered near the edifice. Shows the updating of the volcanic hazard maps published in 1998, where we identify with SPOT satellite imagery and Google Earth, change in the land use on the slope of volcano, the expansion of the agricultural frontier on the east sides of the Ceboruco volcano. The population inhabiting the area is 70,224 people in 2010, concentrated in 107 localities and growing at an annual rate of 0.37%, also the region that has shown an increased in the vulnerability for the development of economic activities, supported by highway, high road, railroad, and the construction of new highway to Puerto Vallarta, which is built in the southeast sector of the volcano and electrical infrastructure that connect the Cajon and Yesca Dams to Guadalajara city. The most important economic activity in the area is agriculture, with crops of sugar cane (Saccharum officinarum), corn, and jamaica (Hibiscus sabdariffa). Recently it has established tomato and green pepper crops in greenhouses. The regional commercial activities are concentrated in the localities of Ixtlán, Jala and Ahuacatlán. The updated hazard maps are: a) Hazard map of pyroclastic flows, b) Hazard map of lahars and debris flow, and c) Hazard map of ash-fall. The cartographic and database information obtained will be the basis for updating the Operational Plan of the Ceboruco Volcano by the State Civil & Fire Protection Unit of Nayarit, Mexico, and the urban development plans of surrounding municipalities, in order to reduce their vulnerability to the hazards of the volcanic activity.

Suarez-Plascencia, C.; Camarena-Garcia, M. A.; Nunez-Cornu, F. J.

2012-12-01

284

Evidence for two shield volcanoes exposed on the island of Kauai, Hawaii  

USGS Publications Warehouse

The island of Kauai has always been interpreted as a single shield volcano, but lavas of previously correlated reversed-to-normal magnetic-polarity transitions on opposite sides of the island differ significantly in isotopic composition. Samples from west Kauai have 87Sr/86Sr 18.25; samples from east Kauai have 87Sr/86Sr > 0.7037, ??Nd ??? 6.14, and 206Pb/204Pb < 18.25. Available data suggest that a younger eastern shield grew on the collapsed flank of an older western one.

Holcomb, R.T.; Reiners, P.W.; Nelson, B.K.; Sawyer, N.-L.E.

1997-01-01

285

Climate model calculations of the effects of volcanoes on global climate  

NASA Technical Reports Server (NTRS)

An examination of the Northern Hemisphere winter surface temperature patterns after the 12 largest volcanic eruptions from 1883-1992 shows warming over Eurasia and North America and cooling over the Middle East which are significant at the 95 percent level. This pattern is found in the first winter after tropical eruptions, in the first or second winter after midlatitude eruptions, and in the second winter after high latitude eruptions. The effects are independent of the hemisphere of the volcanoes. An enhanced zonal wind driven by heating of the tropical stratosphere by the volcanic aerosols is responsible for the regions of warming, while the cooling is caused by blocking of incoming sunlight.

Robock, Alan

1992-01-01

286

Preliminary Slope-Stability Analysis of Augustine Volcano  

USGS Publications Warehouse

Augustine Volcano has been a prolific producer of large debris avalanches during the Holocene. Originating as landslides from the steep upper edifice, these avalanches typically slide into the surrounding ocean. At least one debris avalanche that occurred in 1883 during an eruption initiated a far-traveled tsunami. The possible occurrence of another edifice collapse and ensuing tsunami was a concern during the 2006 eruption of Augustine. To aid in hazard assessments, we have evaluated the slope stability of Augustine's edifice, using a quasi-three-dimensional, geotechnically based slope-stability model implemented in the computer program SCOOPS. We analyzed the effects of topography, variations in rock strength, and earthquake-induced strong ground motion on the relative stability of millions of potential large (>0.1 km3 volume) slope failures throughout the edifice. Preliminary results from pre-2006 topography provide three insights. First, the predicted stability of all parts of the upper edifice is approximately the same, suggesting an equal likelihood of slope failure, in agreement with geologic observations that debris avalanches have swept all sectors of the volcano. Second, the least stable (by a small amount) sector is on the east flank where a debris avalanche would flow into deeper ocean water and a resulting tsunami would be directed toward the southwestern part of the Kenai Peninsula. Third, most model scenarios predict stable edifice slopes, and only scenarios assuming extensive weak rocks and moderate to strong ground shaking predict potential large collapses. Because other transient triggering mechanisms, such as shallow magma intrusion, may be needed to instigate slope instability, monitoring ground deformation and seismicity could

Reid, Mark E.; Brien, Dianne L.; Waythomas, Christopher F.

2010-01-01

287

Volcanoes in the Classroom--an Explosive Learning Experience.  

ERIC Educational Resources Information Center

Presents a unit on volcanoes for third- and fourth-grade students. Includes demonstrations; video presentations; building a volcano model; and inviting a scientist, preferably a vulcanologist, to share his or her expertise with students. (JRH)

Thompson, Susan A.; Thompson, Keith S.

1996-01-01

288

Don Swanson at Ash Outcrop Near Volcano Observatory  

USGS Multimedia Gallery

Don Swanson (USGS Hawaiian Volcano Observatory) shows scientists in the CSAV International class how layers of ash outside of HVO indicate past explosive eruptions of Kilauea. Hawaiian Volcano Observatory, Hawaii Island, Hawaii...

289

Effects of Volcanoes on the Natural Environment  

NASA Technical Reports Server (NTRS)

The primary focus of this project has been on the development of techniques to study the thermal and gas output of volcanoes, and to explore our options for the collection of vegetation and soil data to enable us to assess the impact of this volcanic activity on the environment. We originally selected several volcanoes that have persistent gas emissions and/or magma production. The investigation took an integrated look at the environmental effects of a volcano. Through their persistent activity, basaltic volcanoes such as Kilauea (Hawaii) and Masaya (Nicaragua) contribute significant amounts of sulfur dioxide and other gases to the lower atmosphere. Although primarily local rather than regional in its impact, the continuous nature of these eruptions means that they can have a major impact on the troposphere for years to decades. Since mid-1986, Kilauea has emitted about 2,000 tonnes of sulfur dioxide per day, while between 1995 and 2000 Masaya has emotted about 1,000 to 1,500 tonnes per day (Duffel1 et al., 2001; Delmelle et al., 2002; Sutton and Elias, 2002). These emissions have a significant effect on the local environment. The volcanic smog ("vog" ) that is produced affects the health of local residents, impacts the local ecology via acid rain deposition and the generation of acidic soils, and is a concern to local air traffic due to reduced visibility. Much of the work that was conducted under this NASA project was focused on the development of field validation techniques of volcano degassing and thermal output that could then be correlated with satellite observations. In this way, we strove to develop methods by which not only our study volcanoes, but also volcanoes in general worldwide (Wright and Flynn, 2004; Wright et al., 2004). Thus volcanoes could be routinely monitored for their effects on the environment. The selected volcanoes were: Kilauea (Hawaii; 19.425 N, 155.292 W); Masaya (Nicaragua; 11.984 N, 86.161 W); and Pods (Costa Rica; 10.2OoN, 84.233 W).

Mouginis-Mark, Peter J.

2005-01-01

290

Volcanoes and volcanic provinces - Martian western hemisphere  

NASA Technical Reports Server (NTRS)

The recognition of some Martian landforms as volcanoes is based on their morphology and geologic setting. Other structures, however, may exhibit classic identifying features to a varying or a less degree; these may be only considered provisionally as having a volcanic origin. Regional geologic mapping of the western hemisphere of Mars from Viking images has revealed many more probable volcanoes and volcanotectonic features than were recognized on Mariner 9 pictures. These abundant volcanoes have been assigned to several distinct provinces on the basis of their areal distribution. Although the Olympus-Tharsis region remains as the principle center of volcanism on Mars, four other important provinces are now also recognized: the lowland plains, Tempe Terra plateau, southern highlands (in the Phaethontis and Thaumasia quadrangles), and a probable ignimbrite province, situated along the highland-lowland boundary in Amazonis Planitia. Volcanoes in any one province vary in morphlogy, size, and age, but volcanoes in each province tend to have common characteristics that distinguish that particular group.

Scott, D. H.

1982-01-01

291

Space Radar Image of Rabaul Volcano, New Guinea  

NASA Technical Reports Server (NTRS)

This is a radar image of the Rabaul volcano on the island of New Britain, Papua, New Guinea taken almost a month after its September 19, 1994, eruption that killed five people and covered the town of Rabaul and nearby villages with up to 75 centimeters (30 inches) of ash. More than 53,000 people have been displaced by the eruption. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on its 173rd orbit on October 11, 1994. This image is centered at 4.2 degrees south latitude and 152.2 degrees east longitude in the southwest Pacific Ocean. The area shown is approximately 21 kilometers by 25 kilometers (13 miles by 15.5 miles). North is toward the upper right. The colors in this image were obtained using the following radar channels: red represents the L-band (horizontally transmitted and received); green represents the L-band (horizontally transmitted and vertically received); blue represents the C-band (horizontally transmitted and vertically received). Most of the Rabaul volcano is underwater and the caldera (crater) creates Blanche Bay, the semi-circular body of water that occupies most of the center of the image. Volcanic vents within the caldera are visible in the image and include Vulcan, on a peninsula on the west side of the bay, and Rabalanakaia and Tavurvur (the circular purple feature near the mouth of the bay) on the east side. Both Vulcan and Tavurvur were active during the 1994 eruption. Ash deposits appear red-orange on the image, and are most prominent on the south flanks of Vulcan and north and northwest of Tavurvur. A faint blue patch in the water in the center of the image is a large raft of floating pumice fragments that were ejected from Vulcan during the eruption and clog the inner bay. Visible on the east side of the bay are the grid-like patterns of the streets of Rabaul and an airstrip, which appears as a dark northwest-trending band at the right-center of the image. Ashfall and subsequent rains caused the collapse of most buildings in the town of Rabaul. Mudflows and flooding continue to pose serious threats to the town and surrounding villages. Volcanologists and local authorities expect to use data such as this radar image to assist them in identifying the mechanisms of the eruption and future hazardous conditions that may be associated with the vigorously active volcano. Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI), with the Deutsche Forschungsanstalt fuer Luft und Raumfahrt e.v.(DLR), the major partner in science, operations and data processing of X-SAR.

1994-01-01

292

The First Historical Eruption of Anatahan Volcano, Mariana Islands  

NASA Astrophysics Data System (ADS)

The first historical eruption of Anatahan volcano occurred on May 10, 2003. The MARGINS office responded by authorizing helicopter surveillance and ship deployment to visit the volcano. The helicopter flight on May 19 allowed visual observations and identification of the east crater as the source of the eruption. The top of the plume was estimated to be at 10,000 ft - significantly less than the 30,000 ft of the initial blast. No bombs were ejected out of the east crater at this time but were falling back into the crater. The bombs looked irregular in shape, massive and were estimated to be a few m in diameter. Bombs and tephra samples were collected from the eastern side of the island when blasts were occurring at a rate of approx. 1 per 5min. The ship visit followed on May 21 to the western side of the island for collection of samples and SO2 flux measurements, along with maintenance of a previously deployed seismometer. Volcanic samples collected on Anatahan consisted of bombs, ash and scoria from the present eruption and old lavas (age unknown). The ash section on the western shore was 25 cm thick and consisted of the following sequence (bottom to top): 0-5 inversely? graded dark ash with scoria and pumice clasts (1-2 cm), 20-25 cm: well sorted clast-supported scoria (max 2 cm) with some fine ash. The maximum total thickness measured at a site 6 km from the east crater was approximately 45 cm. The sequence is interpreted as 1) initial blast 2) interaction of magma with water (from pre-existing hydrothermal system) as evidenced by accretionary lapilli 3) magmatic phase of the eruption producing juvenile material. Electron microprobe analyses of the pumice and scoria show uniform compositions of ~ 60wt% SiO2 in the glass; zoned plagioclase with average composition of 61% An, 37.7% Ab, 1.2% Or; pyroxenes (19.4% Wo, 53.4% En, 26.7% Fs) and Fe-Ti oxides. Sulfur and Cl contents are approx. 100 and 1500 ppm, respectively. Water content of the glass may be several wt% based on analytical totals. Volatile emissions from the volcano were measured by traversing under the plume with a ship-based COSPEC. Using wind speed data from NOAA (10-15 knots on May 21), we estimate the daily SO2 flux to be 3000 - 4500 tons. Our observations are consistent with the idea that the initial phreatic eruption evolved rapidly into a magmatic phase producing juvenile (and vesicular) material accompanied by a high SO2 flux. Details on the eruption products, chemical analyses, seismic measurements, and current monitoring efforts can be found in accompanying posters.

Fischer, T. P.; Hilton, D. R.; Demoor, J.; Jaffe, L.; Spilde, M. N.; Counce, D.; Camacho, J. T.

2003-12-01

293

Predicting The Timing And Location of the Next Hawaiian Volcano  

NSDL National Science Digital Library

The wealth of geologic data on Hawaiian volcanoes makes them ideal for study by middle school students. In this paper the authors use existing data on the age and location of Hawaiian volcanoes to predict the location of the next Hawaiian volcano and when it will begin to grow on the floor of the Pacific Ocean. An inquiry-based lesson is also included in which students use their own calculations to predict when the next volcano on the Kea trend should appear.

Russo, Joseph; Mattox, Stephen; Kidau, Nicole

2010-01-01

294

CSAV Deformation Module Field Trip on Kilauea Volcano  

USGS Multimedia Gallery

Hawaiian Volcano Observatory geologist Michael Poland explaining to international volcano scientists that faulting in this area of Kilauea Volcano can be quantified by looking at the magnitude of fracture opening versus the age of lavas, and that 30 meters of extension has occurred in the past ~600 ...

295

Lab using Volcano Scenarios: Hazard Maps and Communicating Risk  

NSDL National Science Digital Library

This is a lab activity in which small groups of students work with maps, rocks, photographs of volcanic deposits, and textual data to construct a hazard map and a risk communication plan for a specific volcano. Each group is assigned a "volcano scenario," which is based on real volcanoes.

LeeAnn Srogi

296

Methane emission from the mud volcanoes of Sicily (Italy)  

Microsoft Academic Search

Mud volcanoes represent the largest expression of natural methane release into the atmosphere; however, the gas flux has never been investigated in detail. Methane output from vents and diffuse soil degassing is herewith reported for the first time. Measurements were carried out at 5 mud volcano fields around Sicily (Italy). Each mud volcano is characterized by tens of vents and

G. Etiope; A. Caracausi; R. Favara; F. Italiano; C. Baciu

2002-01-01

297

Volcano watch Monitoring risk on Auckland's volcanic field  

E-print Network

Volcano watch Monitoring risk on Auckland's volcanic field Lest we forget Our Memory Lab@auckland.ac.nz Volcano watchThe recent eruptions at Mt Tongariro and White Island are a timely reminder for Auckland (pictured with Lucy McGee, who has recently completed her doctorate) is dating the city's 50 volcanoes

Auckland, University of

298

Living with Volcanoes: Year Eleven Teaching Resource Unit.  

ERIC Educational Resources Information Center

Presents a unit on volcanoes and experiences with volcanoes that helps students develop geography skills. Focuses on four volcanoes: (1) Rangitoto Island; (2) Lake Pupuke; (3) Mount Smart; and (4) One Tree Hill. Includes an answer sheet and resources to use with the unit. (CMK)

Le Heron, Kiri; Andrews, Jill; Hooks, Stacey; Larnder, Michele; Le Heron, Richard

2000-01-01

299

Nanoscale Volcanoes: Accretion of Matter at Ion Sculpted Nanopores  

E-print Network

Nanoscale Volcanoes: Accretion of Matter at Ion Sculpted Nanopores Toshiyuki Mitsui, Derek Stein demonstrate the formation of nanoscale volcano-like structures induced by ion beam irradiation of nanoscale pores in freestanding silicon nitride membranes. Accreted matter is delivered to the volcanoes from

Golovchenko, Jene A.

300

QUANTIFICATION OF THE SPATIAL RELATIONSHIPS BETWEEN FAULTS AND VOLCANOES  

E-print Network

QUANTIFICATION OF THE SPATIAL RELATIONSHIPS BETWEEN FAULTS AND VOLCANOES Wetmore, Paul H of Geology, University of South Florida, Tampa, FL 33620 The perception that faults and volcanoes that most volcanoes and volcanic fields are spatially associated with faults, as well the occurrence

Wetmore, Paul H.

301

Eruptions of Hawaiian Volcanoes--Past, Present, and Future  

E-print Network

Eruptions of Hawaiian Volcanoes-- Past, Present, and Future U.S. Department of the Interior U of Kïlauea Volcano. (USGS photograph by Donald A. Swanson.) *This publication uses English units--Eruption of Kïlauea Volcano, as viewed at dawn on January 30, 1974. Overflows from an active lava lake spill down

Torgersen, Christian

302

Pb Isotopic Evolution of Koolau Volcano (Oahu, Hawaii)  

Microsoft Academic Search

High precision Pb isotopes in Hawaiian shield lavas have revealed the existence of source heterogeneities between volcanoes, as well as within a single volcano during its temporal evolution, e.g. Mauna Kea [1, 2]. The Koolau Scientific Drilling Project (KSDP) was initiated in order to evaluate the long-term evolution of Koolau volcano (Oahu), whose subaerial Makapuu stage lavas define the isotopically

Z. Fekiacova; W. Abouchami

2003-01-01

303

Ground deformation associated with the March 1996 earthquake swarm at Akutan volcano, Alaska, revealed by satellite radar interferometry  

USGS Publications Warehouse

In March 1996 an intense swarm of volcano-tectonic earthquakes (???3000 felt by local residents, Mmax = 5.1, cumulative moment of 2.7 ??1018 N m) beneath Akutan Island in the Aleutian volcanic arc, Alaska, produced extensive ground cracks but no eruption of Akutan volcano. Synthetic aperture radar interferograms that span the time of the swarm reveal complex island-wide deformation: the western part of the island including Akutan volcano moved upward, while the eastern part moved downward. The axis of the deformation approximately aligns with new ground cracks on the western part of the island and with Holocene normal faults that were reactivated during the swarm on the eastern part of the island. The axis is also roughly parallel to the direction of greatest compressional stress in the region. No ground movements greater than 2.83 cm were observed outside the volcano's summit caldera for periods of 4 years before or 2 years after the swarm. We modeled the deformation primarily as the emplacement of a shallow, east-west trending, north dipping dike plus inflation of a deep, Mogi-type magma body beneath the volcano. The pattern of subsidence on the eastern part of the island is poorly constrained. It might have been produced by extensional tectonic strain that both reactivated preexisting faults on the eastern part of the island and facilitated magma movement beneath the western part. Alternatively, magma intrusion beneath the volcano might have been the cause of extension and subsidence in the eastern part of the island. We attribute localized subsidence in an area of active fumaroles within the Akutan caldera, by as much as 10 cm during 1992-1993 and 1996-1998, to fluid withdrawal or depressurization of the shallow hydrothermal system. Copyright 2000 by the American Geophysical Union.

Lu, Z.; Wicks, C., Jr.; Power, J.A.; Dzurisin, D.

2000-01-01

304

(Nearly) Silent Earthquakes on Volcanoes  

NASA Astrophysics Data System (ADS)

Slow, or silent, earthquakes are not restricted to plate boundary zones. Cervellli et al. (Nature, 2002) discovered a slow slip event on Kilauea Volcano, Hawaii that occurred in November 2000. This event, with a moment magnitude of ~ 5.7, had a duration of roughly 36 hours, and slipped a subhorizontal thrust fault at a depth of ~ 5 km. Since that publication, four additional slow earthquakes have been discovered using the Kilauea continuous GPS network. These events are nearly identical to the 2000 event, in pattern of deformation, amplitude, and duration. Inversions for source geometry using simulated annealing place the causative fault in precisely the same location as the 2000 event. In comparison to slow slip events in subduction zones in Cascadia, Japan, Mexico, and elsewhere, the volcanic slow slip events are smaller Mw 5.7 compared to Mw 7 for the larger subduction events, shorter in duration, 1-2 days compared to several years for the Tokai slow slip event, shallower, 5 km as opposed to 30-50 km for most subduction events, and have faster slip rates, ~ 20 m/yr compared to ~ 1 m/yr in Cascadia. The lateral position of the imaged slow event dislocations is directly seaward (updip?) of a prominent, and persistent band of microseismicity on Kilauea. Remarkably, there is a clear increase in seismicity within this region accompanying the slow slip events, although the events (M<3) are far too small to account for the GPS displacements. The temporal and spatial association suggests that the earthquakes are triggered by the otherwise silent slip. We are currently investigating whether non-volcanic tremor also accompanies these slip events.

Segall, P.; Desmarais, E.; Miklus, A.; Okubo, P.

2005-12-01

305

Venus small volcano classification and description  

NASA Technical Reports Server (NTRS)

The high resolution and global coverage of the Magellan radar image data set allows detailed study of the smallest volcanoes on the planet. A modified classification scheme for volcanoes 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 volcanoes located and described by this author during data collection for the Magellan Volcanic and Magmatic Feature Catalog. This global study of approximately 10 exp 4 volcanoes provides new information for refining small volcano classification based on individual characteristics. Total number of these volcanoes 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 volcanoes 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 volcanoes 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.

Aubele, J. C.

1993-01-01

306

In search of ancestral Kilauea volcano  

USGS Publications Warehouse

Submersible observations and samples show that the lower south flank of Hawaii, offshore from Kilauea volcano and the active Hilina slump system, consists entirely of compositionally diverse volcaniclastic rocks; pillow lavas are confined to shallow slopes. Submarine-erupted basalt clasts have strongly variable alkalic and transitional basalt compositions (to 41% SiO2, 10.8% alkalies), contrasting with present-day Kilauea tholeiites. The volcaniclastic rocks provide a unique record of ancestral alkalic growth of an archetypal hotspot volcano, including transition to its tholeiitic shield stage, and associated slope-failure events.

Lipman, P.W.; Sisson, T.W.; Ui, T.; Naka, J.

2000-01-01

307

Tracking Pyroclastic Flows at Soufrière Hills Volcano  

NASA Astrophysics Data System (ADS)

Explosive volcanic eruptions typically show a huge column of ash and debris ejected into the stratosphere, crackling with lightning. Yet equally hazardous are the fast moving avalanches of hot gas and rock that can rush down the volcano's flanks at speeds approaching 280 kilometers per hour. Called pyroclastic flows, these surges can reach temperatures of 400°C. Fast currents and hot temperatures can quickly overwhelm communities living in the shadow of volcanoes, such as what happened to Pompeii and Herculaneum after the 79 C.E. eruption of Italy's Mount Vesuvius or to Saint-Pierre after Martinique's Mount Pelée erupted in 1902.

Ripepe, Maurizio; De Angelis, Silvio; Lacanna, Giorgio; Poggi, Pasquale; Williams, Carlisle; Marchetti, Emanuele; Delle Donne, Dario; Ulivieri, Giacomo

2009-07-01

308

Volcano shapes, entropies, and eruption probabilities  

NASA Astrophysics Data System (ADS)

We propose that the shapes of polygenetic volcanic edifices reflect the shapes of the associated probability distributions of eruptions. In this view, the peak of a given volcanic edifice coincides roughly with the peak of the probability (or frequency) distribution of its eruptions. The broadness and slopes of the edifices vary widely, however. The shapes of volcanic edifices can be approximated by various distributions, either discrete (binning or histogram approximation) or continuous. For a volcano shape (profile) approximated by a normal curve, for example, the broadness would be reflected in its standard deviation (spread). Entropy (S) of a discrete probability distribution is a measure of the absolute uncertainty as to the next outcome/message: in this case, the uncertainty as to time and place of the next eruption. A uniform discrete distribution (all bins of equal height), representing a flat volcanic field or zone, has the largest entropy or uncertainty. For continuous distributions, we use differential entropy, which is a measure of relative uncertainty, or uncertainty change, rather than absolute uncertainty. Volcano shapes can be approximated by various distributions, from which the entropies and thus the uncertainties as regards future eruptions can be calculated. We use the Gibbs-Shannon formula for the discrete entropies and the analogues general formula for the differential entropies and compare their usefulness for assessing the probabilities of eruptions in volcanoes. We relate the entropies to the work done by the volcano during an eruption using the Helmholtz free energy. Many factors other than the frequency of eruptions determine the shape of a volcano. These include erosion, landslides, and the properties of the erupted materials (including their angle of repose). The exact functional relation between the volcano shape and the eruption probability distribution must be explored for individual volcanoes but, once established, can be used to assess the probability of eruptions in relation to the shape of the volcano. These methods can also be applied to the probability of injected dykes reaching the surface in a volcano. We show how the thickness distributions of dykes can be used to estimated their height (dip-dimension) distributions and, for a given magma source and volcano geometry, their probability of erupting. From the calculated energy (mainly elastic and thermal) of the host volcano, and other constraints, the maximum-entropy method can be used to improve the reliability of the assessment of the likelihood of eruption during an unrest period. Becerril, L., Galindo, I., Gudmundsson, A., Morales, J.M., 2013. Depth of origin of magma in eruptions. Sci. Rep., 3 : 2762, doi: 10.1038/srep02762 Gudmundsson, A., 2012 Strengths and strain energies of volcanic edifices: implications for eruptions, collapse calderas, and landslides. Nat. Hazards Earth Syst. Sci., 12, 2241-2258. Gudmundsson, A., Mohajeri, N., 2013. Relations between the scaling exponents, entropies, and energies of fracture networks. Bull. Geol. Soc. France, 184, 377-387. Mohajeri, N., Gudmundsson, A., 2012. Entropies and scaling exponents of street and fracture networks. Entropy, 14, 800-833.

Gudmundsson, Agust; Mohajeri, Nahid

2014-05-01

309

Mobile Response Team Saves Lives in Volcano Crises  

USGS Publications Warehouse

The world's only volcano crisis response team, organized and operated by the USGS, can be quickly mobilized to assess and monitor hazards at volcanoes threatening to erupt. Since 1986, the team has responded to more than a dozen volcano crises as part of the Volcano Disaster Assistance Program (VDAP), a cooperative effort with the Office of Foreign Disaster Assistance of the U.S. Agency for International Development. The work of USGS scientists with VDAP has helped save countless lives, and the valuable lessons learned are being used to reduce risks from volcano hazards in the United States.

Ewert, John W.; Miller, C. Dan; Hendley, James W., II; Stauffer, Peter H.

1997-01-01

310

Research Article Evolution of West Rota Volcano, an extinct submarine volcano in the  

E-print Network

submarine eruption. The youngest unit consists of 1­2 m diam- eter spheroids of rhyolite pumice, interpreted mineralization, Mariana Arc, pumice, Quaternary volcano, submarine caldera. INTRODUCTION The 3000-km long Izu

Stern, Robert J.

311

Volcano monitoring using GPS: Developing data analysis strategies based on the June 2007 Klauea Volcano intrusion  

E-print Network

] The global positioning system (GPS) is one of the most common techniques, and the current state of the art, global positioning system (GPS) volcano monitoring systems must be installed on the ground and thus

312

Galactic Super Volcano Similar to Iceland Volcano - Duration: 2:02.  

NASA Video Gallery

This composite image from NASAs Chandra X-ray Observatory with radio data from the Very Large Array shows a cosmic volcano being driven by a black hole in the center of the M87 galaxy. This eruptio...

313

Mantle CO2 degassing at Mt. Vulture volcano (Italy): Relationship between CO2 outgassing of volcanoes and the time of their last eruption  

NASA Astrophysics Data System (ADS)

Mantle volatiles are mainly lost from the Earth to the atmosphere through subaerial and submarine volcanism. Recent studies have shown that degassing of mantle volatiles also occurs from inactive volcanic areas and in tectonically active areas. A new challenge in Earth science is to quantify the mantle-derived flux of volatiles (e.g., CO2) which is important for understanding such diverse issues as the evolution of the atmosphere, the relationships between magma degassing and volcanic activity, gas pressure and seismogenic processes, and the hazards posed by volcanic lakes. Here we present a detailed study of mantle-derived CO2 budget from Mt. Vulture volcano in the Apennines, Italy, whose latest eruption occurred 141 ± 11 kyr ago. The relationship between ?13CCO2 and total dissolved carbon at Mt. Vulture volcano indicates that the emitted CO2 is a mixture of a biogenic end-member with an average ?13CCO2 of about - 17 ‰ and a mantle-derived CO2 end-member with ?13CCO2 values from - 3 ‰ to + 2 ‰. These values of mantle-derived ?13CCO2 are in the range of those for gas emitted from active volcanoes in the Mediterranean. We calculated the contribution of individual components (CO2 in groundwater, in lakes and from main pools) to the total CO2 budget in the area. We used new measurements of water flow, combined with literature data, to calculate the CO2 flux associated with groundwater, and measured the gas flux from the main pools on the volcanic edifice. Finally, we calculated the CO2 flow in the lakes based on the gradient concentration and eddy diffusivity. The total mantle-derived CO2 budget in the area is 4.85 ×108 molyr-1, which is more than double previous estimates. This is higher than those observed in younger volcanic systems elsewhere, thereby supporting the existence of actively degassing mantle melts below Mt. Vulture volcano. A structural map highlights the tectonic control on CO2 flow across the Mt. Vulture volcanic edifice. Indeed, the tectonic discontinuities that controlled the magma upwelling during the most recent volcanic activity are still the main active degassing structures. The new estimate of CO2 budget in the Mt. Vulture area, together with literature data on CO2 budget from historically active and inactive Italian volcanoes, suggests a power-law functional relationship between the age of the most recent volcanic eruption and both total discharged CO2 (R2 = 0.73) and volcano size-normalized CO2 flux (R2 = 0.66). This relation is also valid by using data from worldwide volcanoes highlighting that deep degassing can occur over very long time too. In turn, the highlighted relation provides also an important tool to better evaluate the state of activity of a volcano, whose last activity occurred far in time. Finally, our study highlights that in the southern Apennines, an active degassing of mantle-derived volatiles (i.e., He, CO2) occurs indiscriminately from west to east. This is in contrast to the central-northern Apennine, which is characterized by a crustal radiogenic volatile contribution, which increases eastward, coupled to a decrease in deep CO2 flux. This difference between the two regions is probably due to lithospheric tears which control the upwelling of mantle melts, their degassing and the transport of volatiles through the crust.

Caracausi, Antonio; Paternoster, Michele; Nuccio, Pasquale Mario

2015-02-01

314

Steady subsidence of Medicine Lake volcano, northern California, revealed by repeated leveling surveys  

USGS Publications Warehouse

Leveling surveys of a 193-km circuit across Medicine Lake volcano (MLV) in 1954 and 1989 show that the summit area subsided by as much as 302 ?? 30 mm (-8.6 ?? 0.9 mm/yr) with respect to a datum point near Bartle, California, 40 km to the southwest. This result corrects an error in the earlier analysis of the same data by Dzurisin et al. [1991], who reported the subsidence rate as -11.1 ?? 1.2 mm/yr. The subsidence pattern extends across the entire volcano, with a surface area of nearly 2000 km2. Two areas of localized subsidence by as much as 20 cm can be attributed to shallow normal faulting near the volcano's periphery. Surveys of an east-west traverse across Lava Beds National Monument on the north flank of the volcano in 1990 and of a 23-km traverse across the summit area in 1999 show that subsidence continued at essentially the same rate during 1989-1999 as 1954-1989. Volcano-wide subsidence can be explained by either a point source of volume loss (Mogi) or a contracting horizontal rectangular dislocation (sill) at a depth of 10-11 km. Volume loss rate estimates range from 0.0013 to 0.0032 km3/yr, depending mostly on the source depth estimate and source type. Based on first-order quantitative considerations, we can rule out that the observed subsidence is due to volume loss from magma withdrawal, thermal contraction, or crystallizing magma at depth. Instead, we attribute the subsidence and faulting to: (1 gravitational loading of thermally weakened crust by the mass of the volcano and associated intrusive rocks, and (2) thinning of locally weakened crust by Basin and Range deformation. The measured subsidence rate exceeds long-term estimates from drill hole data, suggesting that over long timescales, steady subsidence and episodic uplift caused by magmatic intrusions counteract each other to produce the lower net subsidence rate.

Dzurisin, D.; Poland, M.P.; Burgmann, R.

2002-01-01

315

Characteristics and management of the 2006-2008 volcanic crisis at the Ubinas volcano (Peru)  

NASA Astrophysics Data System (ADS)

Ubinas volcano is located 75 km East of Arequipa and ca. 5000 people are living within 12 km from the summit. This composite cone is considered the most active volcano in southern Peru owing to its 24 low to moderate magnitude (VEI 1-3) eruptions in the past 500 years. The onset of the most recent eruptive episode occurred on 27 March 2006, following 8 months of heightened fumarolic activity. Vulcanian explosions occurred between 14 April 2006 and September 2007, at a time ejecting blocks up to 40 cm in diameter to distances of 2 km. Ash columns commonly rose to 3.5 km above the caldera rim and dispersed fine ash and aerosols to distances of 80 km between April 2006 and April 2007. Until April 2007, the total volume of ash was estimated at 0.004 km 3, suggesting that the volume of fresh magma was small. Ash fallout has affected residents, livestock, water supplies, and crop cultivation within an area of ca. 100 km 2 around the volcano. Continuous degassing and intermittent mild vulcanian explosions lasted until the end of 2008. Shortly after the initial explosions on mid April 2006 that spread ash fallout within 7 km of the volcano, an integrated Scientific Committee including three Peruvian institutes affiliated to the Regional Committee of Civil Defense for Moquegua, aided by members of the international cooperation, worked together to: i) elaborate and publish volcanic hazard maps; ii) inform and educate the population; and iii) advise regional authorities in regard to the management of the volcanic crisis and the preparation of contingency plans. Although the 2006-2008 volcanic crisis has been moderate, its management has been a difficult task even though less than 5000 people now live around the Ubinas volcano. However, the successful management has provided experience and skills to the scientific community. This volcanic crisis was not the first one that Peru has experienced but the 2006-2008 experience is the first long-lasting crisis that the Peruvian civil authorities have had to cope with, including attempts to utilize a new alert-level scheme and communications system, and the successful evacuation of 1150 people. Lessons learned can be applied to future volcanic crises in southern Peru, particularly in the case of reawakening of El Misti volcano nearby Arequipa.

Rivera, Marco; Thouret, Jean-Claude; Mariño, Jersy; Berolatti, Rossemary; Fuentes, José

2010-12-01

316

Digital data set of volcano hazards for active Cascade Volcanos, Washington  

USGS Publications Warehouse

Scientists at the Cascade Volcano Observatory have completed hazard assessments for the five active volcanos in Washington. The five studies included Mount Adams (Scott and others, 1995), Mount Baker (Gardner and others, 1995), Glacier Peak (Waitt and others, 1995), Mount Rainier (Hoblitt and others, 1995) and Mount St. Helens (Wolfe and Pierson, 1995). Twenty Geographic Information System (GIS) data sets have been created that represent the hazard information from the assessments. The twenty data sets have individual Open File part numbers and titles

Schilling, Steve P.

1996-01-01

317

Reevaluation of tsunami formation by debris avalanche at Augustine Volcano, Alaska  

USGS Publications Warehouse

Debris avalanches entering the sea at Augustine Volcano, Alaska have been proposed as a mechanism for generating tsunamis. Historical accounts of the 1883 eruption of the volcano describe 6- to 9-meter-high waves that struck the coastline at English Bay (Nanwalek), Alaska about 80 kilometers east of Augustine Island. These accounts are often cited as proof that volcanigenic tsunamis from Augustine Volcano are significant hazards to the coastal zone of lower Cook Inlet. This claim is disputed because deposits of unequivocal tsunami origin are not evident at more than 50 sites along the lower Cook Inlet coastline where they might be preserved. Shallow water (<25 m) around Augustine Island, in the run-out zone for debris avalanches, limits the size of an avalanche-caused wave. If the two most recent debris avalanches, Burr Point (A.D. 1883) and West Island (<500 yr. B.P.) were traveling at velocities in the range of 50 to 100 meters per second, the kinetic energy of the avalanches at the point of impact with the ocean would have been between 1014 and 1015 joules. Although some of this energy would be dissipated through boundary interactions and momentum transfer between the avalanche and the sea, the initial wave should have possessed sufficient kinetic energy to do geomorphic work (erosion, sediment transport, formation of wave-cut features) on the coastline of lowwer Cook Inlet. Because widespread evidence of the effects of large waves cannot be found, it appears that the debris avalanches could not have been traveling very fast when they entered the sea, or they happened during low tide and displaced only small volumes of water. In light of these results, the hazard from volcanigenic tsunamis from Augustine Volcano appears minor, unless a very large debris avalanche occurs at high tide.

Waythomas, C.F.

2000-01-01

318

Dynamics and deposits of multiple pyroclastic density currents associated with the May 2008 eruption of Chaitén volcano (Chile)  

NASA Astrophysics Data System (ADS)

Explosive activity at Chaitén volcano in southern Chile, a 3-km-diameter caldera with a 0.5 km3 pre-eruption rhyolite lava dome, triggered multiple moderate- to low-temperature, dilute, pyroclastic density currents (PDCs) from 2-7 May 2008. Flows were focused predominantly in discrete sectors north and east of the volcano. A blast-like PDC leveled a 2-km-long, 4-km2 swath of trees north of the volcano, removing trees near the volcano's rim but causing only minor abrasion and leaf kill at its distal limit. Felled trees pointing in the down-current direction dominate the disturbance zone. The PDC left a decimeters-thick friable deposit grading upward from poorly sorted, fines depleted, pumiceous coarse ash and fine lapilli to pumiceous and lithic coarse ash. Fragments of charred and uncharred wood are concentrated in the basal half of the deposit, but vegetation protruding above the deposit is largely uncharred. Thin overlying layers of tephra fall suggest the PDC deposit was emplaced during the initial explosive phase on 2 May. Deposit characteristics and forest impacts suggest that the current was of moderate temperature (< 300°C), dilute, highly mobile and energetic, having a dynamic pressure of 2-4 kPa and a minimum, near-ground velocity of 30-40 ms-1. A similar and probably contemporaneous PDC felled approximately 2 km2 of forest on the northeast flank of the volcano. Deposits and impacts of PDCs east of the volcano contrast with that to the north. To the east, PDC(s) defoliated large trees on the outer flank, but tree boles, some with intact limbs, remained standing and unabraded; bark and epiphytes were largely intact and uncharred. However, small understory trees were broken with their tops pointed downhill, and ash clung to vertical tree boles to a height of several meters above ground surface. One or more PDCs left meter-scale dunes on the caldera floor, composed of stratified beds of friable pumice lapilli, pumiceous and lithic coarse ash, and faintly stratified ash and polymictic lapilli. Similarly stratified beds preserved at the low point on the east caldera rim show that the PDC(s) swept over the rim at this point. The deposit on the outer eastern flank is 2-3 m thick and composed of curviplanar, discontinuous beds of fine to coarse ash supporting scattered pumice lapilli. At Chaitén volcano, there is no evidence that sector collapse or significant dome collapse rapidly decompressed a magma body or controlled the azimuth of directed PDCs. We therefore hypothesize that northward- and northeastward-directed, blast-like PDCs were caused by rapid decompression associated with vent opening along the most propitious, subvertical fissures that existed in the old lava dome, possibly aided by vent asymmetry. A similar mechanism has been inferred for the blast event during the 1902 eruption of Mount Pelée, Martinique. We infer that PDC(s) affecting the east flank of Chaitén formed by column collapse and partial spillover at the low point on the east rim. Such limited and low-temperature PDCs are noteworthy for a major explosive rhyolite eruption.

Major, J. J.; Hoblitt, R. P.; Pierson, T. C.; Moreno, H.

2012-12-01

319

Multidisciplinary Monitoring Experiments at Kawah Ijen Volcano  

NASA Astrophysics Data System (ADS)

"Wet volcanoes" with crater lakes and extensive hydrothermal systems pose challenges for monitoring and forecasting eruptions. That's because their lakes and hydrothermal systems serve as reservoirs for magmatic heat and fluid emissions, filtering and delaying the surface expressions of magmatic unrest.

Gunawan, Hendra; Pallister, John; Caudron, Corentin

2014-12-01

320

New volcanoes discovered in southeast Australia  

NASA Astrophysics Data System (ADS)

Scientists have discovered three new active volcanoes in the Newer Volcanics Province (NVP) in southeast Australia. Researchers from Monash University in Melbourne describe in the Australian Journal of Earth Sciences how they used a combination of satellite photographs, detailed topography models from NASA, the distribution of magnetic minerals in the rocks, and site visits to analyze the region.

Wendel, JoAnna

2014-07-01

321

ConcepTest: Movement of Volcano  

NSDL National Science Digital Library

A volcano formed over a hot spot in the Pacific Ocean would travel approximately _______ in 1000 years. (Assume a constant rate of plate motion. 1 km = 1000 m; 1 m = 100 cm; 1 cm = 10 mm.) a. 1-2 meters b. 100-200 ...

322

Volcano Hazards Fact Sheet: Volcanic Gas  

NSDL National Science Digital Library

This fact sheet provides an overview of the gases emitted by volcanoes, which consist mostly of water vapor, carbon dioxide, and sulfur dioxide. Topics include reasons for studying them, potential hazards, methods for studying them, and some facts about the gases emitted by the eruption of Mount St. Helens. A downloadable, printable version is available.

323

Biological Studies on a Live Volcano.  

ERIC Educational Resources Information Center

Describes scientific research on an Earthwatch expedition to study Arenal, one of the world's most active volcanoes, in north central Costa Rica. The purpose of the two-week project was to monitor and understand the past and ongoing development of a small, geologically young, highly active stratovolcano in a tropical, high-rainfall environment.…

Zipko, Stephen J.

1992-01-01

324

Constraining volcano eruption dynamics with infrasound  

Microsoft Academic Search

Infrasonic airwaves produced by exploding volcanoes provide an indispensable tool for understanding dynamics of diverse eruptions. Unlike the seismicity generated during eruption, which is a complex superposition of internal and surface source and wave propagation processes, the infrasonic pressure field can be unequivocally associated with the flux rate of gas released at the volcanic vent. Because the atmosphere does not

J. B. Johnson; R. C. Aster

2003-01-01

325

Glossary of Volcano and Related Terminology  

NSDL National Science Digital Library

This glossary of terms is specific to the discussion of volcanoes. It contains terms such as aa (a type of lava), and silicic (a term used to describe silica-rich volcanic rock or magma). Many of the terms not only have definitions, but serve as active links to sites with additional information about the term.

326

Measuring earthquake and volcano activity from space  

NSDL National Science Digital Library

The student will be introduced to InSAR observations in the beginning of the class via a PPT presentation that explains basic concepts. The activity will expose the student to simple examples of earthquake and volcano activity and better understanding of the colorful phase presentation of interferograms.

Wdowinski, Shimon

327

Taking the Pulse of Yellowstone's "Breathing" Volcano  

NSDL National Science Digital Library

In this activity, students learn about volcanism in Yellowstone National Park, focusing on its history of eruption, recent seismicity, hydrothermal events, and ground deformation. They learn how scientists monitor volcanoes (using Mount St. Helens as an example) and then apply that as an open-ended problem to Yellowstone; their problem is to identify a site for a research station.

Pratt-Sitaula, Beth

328

Volcano geodesy and magma dynamics in Iceland  

Microsoft Academic Search

Here we review the achievements of volcano geodesy in Iceland during the last 15 years. Extensive measurements of crustal deformation have been conducted using a variety of geodetic techniques, including leveling, electronic distance measurements, campaign and continuous Global Positioning System (GPS) geodesy, and interferometric analysis of synthetic aperture radar images (InSAR). Results from these measurements provide a comprehensive view of

Erik Sturkell; Páll Einarsson; Freysteinn Sigmundsson; Halldór Geirsson; Halldór Ólafsson; Rikke Pedersen; Elske de Zeeuw-van Dalfsen; Alan T. Linde; Selwyn I. Sacks; Ragnar Stefánsson

2006-01-01

329

Sangay volcano, Ecuador: structural development, present activity and petrology  

NASA Astrophysics Data System (ADS)

Sangay (5230 m), the southernmost active volcano of the Andean Northern Volcanic Zone (NVZ), sits ˜130 km above a >32-Ma-old slab, close to a major tear that separates two distinct subducting oceanic crusts. Southwards, Quaternary volcanism is absent along a 1600-km-long segment of the Andes. Three successive edifices of decreasing volume have formed the Sangay volcanic complex during the last 500 ka. Two former cones (Sangay I and II) have been largely destroyed by sector collapses that resulted in large debris avalanches that flowed out upon the Amazon plain. Sangay III, being constructed within the last avalanche amphitheater, has been active at least since 14 ka BP. Only the largest eruptions with unusually high Plinian columns are likely to represent a major hazard for the inhabited areas located 30 to 100 km west of the volcano. However, given the volcano's relief and unbuttressed eastern side, a future collapse must be considered, that would seriously affect an area of present-day colonization in the Amazon plain, ˜30 km east of the summit. Andesites greatly predominate at Sangay, there being few dacites and basalts. In order to explain the unusual characteristics of the Sangay suite—highest content of incompatible elements (except Y and HREE) of any NVZ suite, low Y and HREE values in the andesites and dacites, and high Nb/La of the only basalt found—a preliminary five-step model is proposed: (1) an enriched mantle (in comparison with an MORB source), or maybe a variably enriched mantle, at the site of the Sangay, prior to Quaternary volcanism; (2) metasomatism of this mantle by important volumes of slab-derived fluids enriched in soluble incompatible elements, due to the subduction of major oceanic fracture zones; (3) partial melting of this metasomatized mantle and generation of primitive basaltic melts with Nb/La values typical of the NVZ, which are parental to the entire Sangay suite but apparently never reach the surface and subordinate production of high Nb/La basaltic melts, maybe by lower degrees of melting at the periphery of the main site of magma formation, that only infrequently reach the surface; (4) AFC processes at the base of a 50-km-thick crust, where parental melts pond and fractionate while assimilating remelts of similar basaltic material previously underplated, producing andesites with low Y and HREE contents, due to garnet stability at this depth; (5) low-pressure fractionation and mixing processes higher in the crust. Both an enriched mantle under Sangay prior to volcanism and an important slab-derived input of fluids enriched in soluble incompatible elements, two parameters certainly related to the unique setting of the volcano at the southern termination of the NVZ, apparently account for the exceptionally high contents of incompatible elements of the Sangay suite. In addition, the low Cr/Ni values of the entire suite—another unique characteristic of the NVZ—also requires unusual fractionation processes involving Cr-spinel and/or clinopyroxene, either in the upper mantle or at the base of the crust.

Monzier, Michel; Robin, Claude; Samaniego, Pablo; Hall, Minard L.; Cotten, Jo; Mothes, Patricia; Arnaud, Nicolas

1999-05-01

330

The geological evolution of Merapi volcano, Central Java, Indonesia  

NASA Astrophysics Data System (ADS)

Merapi is an almost persistently active basalt to basaltic andesite volcanic complex in Central Java (Indonesia) and often referred to as the type volcano for small-volume pyroclastic flows generated by gravitational lava dome failures (Merapi-type nuées ardentes). Stratigraphic field data, published and new radiocarbon ages in conjunction with a new set of 40K-40Ar and 40Ar-39Ar ages, and whole-rock geochemical data allow a reassessment of the geological and geochemical evolution of the volcanic complex. An adapted version of the published geological map of Merapi [(Wirakusumah et al. 1989), Peta Geologi Gunungapi Merapi, Jawa Tengah (Geologic map of Merapi volcano, Central Java), 1:50,000] is presented, in which eight main volcano stratigraphic units are distinguished, linked to three main evolutionary stages of the volcanic complex—Proto-Merapi, Old Merapi and New Merapi. Construction of the Merapi volcanic complex began after 170 ka. The two earliest (Proto-Merapi) volcanic edifices, Gunung Bibi (109 ± 60 ka), a small basaltic andesite volcanic structure on Merapi's north-east flank, and Gunung Turgo and Gunung Plawangan (138 ± 3 ka; 135 ± 3 ka), two basaltic hills in the southern sector of the volcano, predate the Merapi cone sensu stricto. Old Merapi started to grow at ~30 ka, building a stratovolcano of basaltic andesite lavas and intercalated pyroclastic rocks. This older Merapi edifice was destroyed by one or, possibly, several flank failures, the latest of which occurred after 4.8 ± 1.5 ka and marks the end of the Old Merapi stage. The construction of the recent Merapi cone (New Merapi) began afterwards. Mostly basaltic andesite pyroclastic and epiclastic deposits of both Old and New Merapi (<11,792 ± 90 14C years BP) cover the lower flanks of the edifice. A shift from medium-K to high-K character of the eruptive products occurred at ~1,900 14C years BP, with all younger products having high-K affinity. The radiocarbon record points towards an almost continuous activity of Merapi since this time, with periods of high eruption frequency interrupted by shorter intervals of apparently lower eruption rates, which is reflected in the geochemical composition of the eruptive products. The Holocene stratigraphic record reveals that fountain collapse pyroclastic flows are a common phenomenon at Merapi. The distribution and run-out distances of these flows have frequently exceeded those of the classic Merapi-type nuées ardentes of the recent activity. Widespread pumiceous fallout deposits testify the occurrence of moderate to large (subplinian) eruptions (VEI 3-4) during the mid to late Holocene. VEI 4 eruptions, as identified in the stratigraphic record, are an order of magnitude larger than any recorded historical eruption of Merapi, except for the 1872 AD and, possibly, the October-November 2010 events. Both types of eruptive and volcanic phenomena require careful consideration in long-term hazard assessment at Merapi.

Gertisser, Ralf; Charbonnier, Sylvain J.; Keller, Jörg; Quidelleur, Xavier

2012-07-01

331

The Anatahan volcano-monitoring system  

NASA Astrophysics Data System (ADS)

A real-time 24/7 Anatahan volcano-monitoring and eruption detection system is now operational. There had been no real-time seismic monitoring on Anatahan during the May 10, 2003 eruption because the single telemetered seismic station on Anatahan Island had failed. On May 25, staff from the Emergency Management Office (EMO) of the Commonwealth of the Northern Mariana Islands and the U. S. Geological Survey (USGS) established a replacement telemetered seismic station on Anatahan whose data were recorded on a drum recorder at the EMO on Saipan, 130 km to the south by June 5. In late June EMO and USGS staff installed a Glowworm seismic data acquisition system (Marso et al, 2003) at EMO and hardened the Anatahan telemetry links. The Glowworm system collects the telemetered seismic data from Anatahan and Saipan, places graphical display products on a webpage, and exports the seismic waveform data in real time to Glowworm systems at Hawaii Volcano Observatory and Cascades Volcano Observatory (CVO). In early July, a back-up telemetered seismic station was placed on Sarigan Island 40 km north of Anatahan, transmitting directly to the EMO on Saipan. Because there is currently no population on the island, at this time the principal hazard presented by Anatahan volcano would be air traffic disruption caused by possible erupted ash. The aircraft/ash hazard requires a monitoring program that focuses on eruption detection. The USGS currently provides 24/7 monitoring of Anatahan with a rotational seismic duty officer who carries a Pocket PC-cell phone combination that receives SMS text messages from the CVO Glowworm system when it detects large seismic signals. Upon receiving an SMS text message notification from the CVO Glowworm, the seismic duty officer can use the Pocket PC - cell phone to view a graphic of the seismic traces on the EMO Glowworm's webpage to determine if the seismic signal is eruption related. There have been no further eruptions since the monitoring system was installed, but regional tectonic earthquakes have provided frequent tests of the system. Reliance on a Pocket PC - cell phone requires that the seismic duty officer remain in an area with cell phone coverage. With this monitoring method, the USGS is able to provide rapid notice of an Anatahan eruption to the EMO and the Washington Volcano Ash Advisory Center. Reference Marso, J.N., Murray, T.L., Lockhart, A.B., Bryan, C.J., Glowworm: An extended PC-based Earthworm system for volcano monitoring. Abstracts, Cities On Volcanoes III, Hilo Hawaii, July 2003.

Marso, J. N.; Lockhart, A. B.; White, R. A.; Koyanagi, S. K.; Trusdell, F. A.; Camacho, J. T.; Chong, R.

2003-12-01

332

Seismicity at Baru Volcano, Western Panama, Panama  

NASA Astrophysics Data System (ADS)

The Baru volcano in Western Panama (8.808°N, 82.543°W) is a 3,475 m high strato volcano that lies at about 50 km from the Costa Rican border. The last major eruptive event at this volcano occurred c.1550 AD and no further eruptive activity from that time is known. Since the 1930´s, approximately every 30 years a series of seismic swarms take place in the surroundings of the volcanic edifice. Theses swarms last several weeks alarming the population who lives near the volcano. The last of these episodes occurred on May 2006 and lasted one and a half months. More than 20,000 people live adjacent to the volcano and any future eruption has the potential to be very dangerous. In June 2007, a digital seismic monitoring network of ten stations, linked via internet, was installed around the volcano in a collaborative project between the University of Panama and the Panamanian Government. The seismic data acquisition at the sites is performed using LINUX-SEISLOG and the events are recorded by four servers at different locations using the Earth Worm system. In this work we analyze the characteristics of the volcano seismicity recorded from May 4th, 2006 to July 31st, 2008 by at least 4 stations and located at about 15 km from the summit. To determine the seismic parameters, we tested several crustal velocity models and used the seismic analysis software package SEISAN. Our final velocity model was determined using seismic data for the first four km obtained from a temporal seismic network deployed in 1981 by the British Geological Survey (BGS) as part of geothermal studies conducted at Cerro Pando, Western Panama Highlands. Our results indicate that all the events recorded in the quadrant 8.6-9.0°N and 82.2-82.7°W are located in the depth range of 0.1 to 8 km. Cross sections show vertical alignments of hypocenters below the summit although most of the seismicity is concentrated in its eastern flank reaching the town of Boquete. All the calculated focal mechanisms are of the strike slip type.

Camacho, E.; Novelo-Casanova, D. A.; Tapia, A.; Rodriguez, A.

2008-12-01

333

Mechanism of explosive eruptions of Kilauea Volcano, Hawaii  

USGS Publications Warehouse

A small explosive eruption of Kilauea Volcano, Hawaii, occurred in May 1924. The eruption was preceded by rapid draining of a lava lake and transfer of a large volume of magma from the summit reservoir to the east rift zone. This lowered the magma column, which reduced hydrostatic pressure beneath Halemaumau and allowed groundwater to flow rapidly into areas of hot rock, producing a phreatic eruption. A comparison with other events at Kilauea shows that the transfer of a large volume of magma out of the summit reservoir is not sufficient to produce a phreatic eruption. For example, the volume transferred at the beginning of explosive activity in May 1924 was less than the volumes transferred in March 1955 and January-February 1960, when no explosive activity occurred. Likewise, draining of a lava lake and deepening of the floor of Halemaumau, which occurred in May 1922 and August 1923, were not sufficient to produce explosive activity. A phreatic eruption of Kilauea requires both the transfer of a large volume of magma from the summit reservoir and the rapid removal of magma from near the surface, where the surrounding rocks have been heated to a sufficient temperature to produce steam explosions when suddenly contacted by groundwater. ?? 1992 Springer-Verlag.

Dvorak, J.J.

1992-01-01

334

An isotope hydrology study of the Kilauea volcano area, Hawaii  

USGS Publications Warehouse

Isotope tracer methods were used to determine flow paths, recharge areas, and relative age for ground water in the Kilauea volcano area on the Island of Hawaii. Stable isotopes in rainfall show three distinct isotopic gradients with elevation, which are correlated with trade-wind, rain shadow, and high-elevation climatological patterns. Temporal variations in isotopic composition of precipitation are controlled more by the frequency of large storms than b.y seasonal temperature fluctuations. Consistency in results between two separate areas with rainfall caused by tradewinds and thermally-driven upslope airflow suggests that isotopic gradients with elevation may be similar on other islands in the tradewind belt, especially the other Hawaiian Islands, which have similar climatology and temperature lapse rates. Areal contrasts in ground-water stable isotopes and tritium indicate that the volcanic ri~ zones compartmentalize the regional ground-water system. Tritium levels in ground water within and downgradient of Kilauea's ri~ zones indicate relatively long residence times. Part of Kilauea's Southwest Ri~ Zone appears to act as a conduit for water from higher elevation, but there is no evidence for extensive down-ri~ flow in the lower East Ri~ Zone.

Scholl, M.A.; Ingebritsen, S.E.; Janik, C.J.; Kauahikaua, J.P.

1995-01-01

335

Characteristics of Different Types of Volcanoes and Features Type of Form of  

E-print Network

Characteristics of Different Types of Volcanoes and Features Type of Form of Volcano Volcano Size eruption Columbia River slope 1,000,000 km2 from long fissures Iceland 1 to 3 km thick Shield volcano Slightly sloped Up to 9000 m Basalt Gentle, some Hawaii high fire fountains Iceland Composite volcano

Laske, Gabi

336

Space Radar Image of Colombian Volcano  

NASA Technical Reports Server (NTRS)

This is a radar image of a little known volcano in northern Colombia. The image was acquired on orbit 80 of space shuttle Endeavour on April 14, 1994, by the Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR). The volcano near the center of the image is located at 5.6 degrees north latitude, 75.0 degrees west longitude, about 100 kilometers (65 miles) southeast of Medellin, Colombia. The conspicuous dark spot is a lake at the bottom of an approximately 3-kilometer-wide (1.9-mile) volcanic collapse depression or caldera. A cone-shaped peak on the bottom left (northeast rim) of the caldera appears to have been the source for a flow of material into the caldera. This is the northern-most known volcano in South America and because of its youthful appearance, should be considered dormant rather than extinct. The volcano's existence confirms a fracture zone proposed in 1985 as the northern boundary of volcanism in the Andes. The SIR-C/X-SAR image reveals another, older caldera further south in Colombia, along another proposed fracture zone. Although relatively conspicuous, these volcanoes have escaped widespread recognition because of frequent cloud cover that hinders remote sensing imaging in visible wavelengths. Four separate volcanoes in the Northern Andes nations ofColombia and Ecuador have been active during the last 10 years, killing more than 25,000 people, including scientists who were monitoring the volcanic activity. Detection and monitoring of volcanoes from space provides a safe way to investigate volcanism. The recognition of previously unknown volcanoes is important for hazard evaluations because a number of major eruptions this century have occurred at mountains that were not previously recognized as volcanoes. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companiesfor the German space agency, Deutsche Agentur fuer Raumfahrtange-legenheiten (DARA), and the Italian space agency,Agenzia SpazialeItaliana (ASI), with the Deutsche Forschungsanstalt fuer Luft undRaumfahrt e.v.(DLR), the major partner in science,operations, and data processing of X-SAR.

1999-01-01

337

Acid deposition in east Asia  

SciTech Connect

A comparison between transport models was done to study the acid deposition in east Asia. The two models in question were different in the way the treated the pollutant species and the way simulation was carried out. A single-layer, trajectory model with simple (developed by the Central Research Institute of Electric Power Industry (CRIEPI), Japan) was compared with a multi-layered, eulerian type model (Sulfur Transport Eulerian Model - II [STEM-II]) treating the chemical processes in detail. The acidic species used in the simulation were sulfur dioxide and sulfate. The comparison was done for two episodes: each a month long in winter (February) and summer (August) of 1989. The predicted results from STEM-II were compared with the predicted results from the CRIEPI model as well as the observed data at twenty-one stations in Japan. The predicted values from STEM-II were similar to the ones from the CRIEPI results and the observed values in regards to the transport features. The average monthly values of SO{sub 2} in air, sulfate in air and sulfate in precipitation were in good agreement. Sensitivity studies were carried out under different scenarios of emissions, dry depositions velocities and mixing heights. The predicted values in these sensitivity studies showed a strong dependence on the mixing heights. The predicted wet deposition of sulfur for the two months is 0.7 gS/m2.mon, while the observed deposition is around 1.1 gS/m2.mon. It was also observed that the wet deposition on the Japan sea side of the islands is more than those on the Pacific side and the Okhotsk sea, mainly because of the continental outflow of pollutant air masses from mainland China and Korea. The effects of emissions from Russia and volcanoes were also evaluated.

Phadnis, M.J.; Carmichael, G.R. [Univ. of Iowa, Iowa City, IA (United States); Ichikawa, Y. [Central Research Institute of Electric Power Industry, Komae (Japan)

1996-12-31

338

Measurement and interpretation of diffuse gas emission in tectonic structures associated to volcanoes: the case of Volcán de Fuego de Colima  

NASA Astrophysics Data System (ADS)

Diffuse gas emission is used to understand the behavior of volcanoes during eruptive activity or during passive-degassing periods (i.e. diffuse gas emissions of Stromboli volcano have been observed for 10 years; Inguaggiato 2011). Also, diffuse gas emission is used to study the activity of tectonic structures such as faults in some areas as precursors of seismic events. Volcanoes are always associated to tectonic structures. However, few has been done to understand the volcano-tectonic relationships using diffuse emissions as a tool. For instance, Volcán de Fuego de Colima (VFC) is located in a highly active tectonic area such as the Colima graben where the existence of southward-trending faults have been previously documented as well as east-west trending faults (Macías 2005; Norini et al 2010; Cortés et al 2010). VFC is a historically active volcano with major explosive eruptions (most recent in 1913), refilling of the crater, overtopping with growing lava domes and pyroclastic flow events. However, what is the relationship between the tectonic features across the volcano? Are these structures affecting the activity of the volcano? If so, how are they affecting the eruptive activity? Can the tectonic activity be used to understand the evolution of the volcanic activity? In this work we use the diffuse gas emission to answer these questions. For this end, we measured soil CO2 flux and soil H2S flux along the Tamazula fault at more than 300 stations. Also, samples were collected from springs at VFC. Our preliminary results found no indication of significant tectonic activity around the faults to which VFC is associated. This is the first measurement of this kind at VFC and established a baseline we may compare with in the future.

Jácome Paz, M. P.; Delgado Granados, H.; Inguaggiato, S.

2011-12-01

339

Continuous monitoring of volcanoes with borehole strainmeters  

NASA Astrophysics Data System (ADS)

Monitoring of volcanoes using various physical techniques has the potential to provide important information about the shape, size and location of the underlying magma bodies. Volcanoes erupt when the pressure in a magma chamber some kilometers below the surface overcomes the strength of the intervening rock, resulting in detectable deformations of the surrounding crust. Seismic activity may accompany and precede eruptions and, from the patterns of earthquake locations, inferences may be made about the location of magma and its movement. Ground deformation near volcanoes provides more direct evidence on these, but continuous monitoring of such deformation is necessary for all the important aspects of an eruption to be recorded. Sacks-Evertson borehole strainmeters have recorded strain changes associated with eruptions of Hekla, Iceland and Izu-Oshima, Japan. Those data have made possible well-constrained models of the geometry of the magma reservoirs and of the changes in their geometry during the eruption. The Hekla eruption produced clear changes in strain at the nearest instrument (15 km from the volcano) starting about 30 minutes before the surface breakout. The borehole instrument on Oshima showed an unequivocal increase in the amplitude of the solid earth tides beginning some years before the eruption. Deformational changes, detected by a borehole strainmeter and a very long baseline tiltmeter, and corresponding to the remote triggered seismicity at Long Valley, California in the several days immediately following the Landers earthquake are indicative of pressure changes in the magma body under Long Valley, raising the question of whether such transients are of more general importance in the eruption process. We extrapolate the experience with borehole strainmeters to estimate what could be learned from an installation of a small network of such instruments on Mauna Loa. Since the process of conduit formation from the magma sources in Mauna Loa and other volcanic regions should be observable, continuous high sensitivity strain monitoring of volcanoes provides the potential to give short time warnings of impending eruptions. Current technology allows transmission and processing of rapidly sampled borehole strain data in real-time. Such monitoring of potentially dangerous volcanoes on a global scale would provide not only a wealth of scientific information but also significant social benefit, including the capability of diverting nearby in-flight aircraft.

Linde, Alan T.; Sacks, Selwyn

340

HUBBLE SPACE TELESCOPE RESOLVES VOLCANOES ON IO  

NASA Technical Reports Server (NTRS)

This picture is a composite of a black and white near infrared image of Jupiter and its satellite Io and a color image of Io at shorter wavelengths taken at almost the same time on March 5, 1994. These are the first images of a giant planet or its satellites taken by NASA's Hubble Space Telescope (HST) since the repair mission in December 1993. Io is too small for ground-based telescopes to see the surface details. The moon's angular diameter of one arc second is at the resolution limit of ground based telescopes. Many of these markings correspond to volcanoes that were first revealed in 1979 during the Voyager spacecraft flyby of Jupiter. Several of the volcanoes periodically are active because Io is heated by tides raised by Jupiter's powerful gravity. The volcano Pele appears as a dark spot surrounded by an irregular orange oval in the lower part of the image. The orange material has been ejected from the volcano and spread over a huge area. Though the volcano was first discovered by Voyager, the distinctive orange color of the volcanic deposits is a new discovery in these HST images. (Voyager missed it because its cameras were not sensitive to the near-infrared wavelengths where the color is apparent). The sulfur and sulfur dioxide that probably dominate Io's surface composition cannot produce this orange color, so the Pele volcano must be generating material with a more unusual composition, possibly rich in sodium. The Jupiter image, taken in near-infrared light, was obtained with HST's Wide Field and Planetary Camera in wide field mode. High altitude ammonia crystal clouds are bright in this image because they reflect infrared light before it is absorbed by methane in Jupiter's atmosphere. The most prominent feature is the Great Red Spot, which is conspicuous because of its high clouds. A cap of high-altitude haze appears at Jupiter's south pole. The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science. Credit: John Spencer, Lowell Observatory; NASA

2002-01-01

341

Increased volcanic unrest at Katla volcano, Iceland?  

NASA Astrophysics Data System (ADS)

The subglacial volcano Katla beneath Mýrdalsjökull ice cap has had twenty confirmed major eruptions breaking the ice cover in the past 1100 years, the most recent one in 1918. Recently, Katla has been showing some signs of increased volcanic unrest. Katla is one of the most seismically active volcanoes in Iceland. It shows an annual cycle in seismic activity. Deformation of the volcano has been studied by use of GPS, InSAR and levelling. The observed deformation field appears to be a complex mixture of signals originating from different sources, that may include plate movements, gradual thinning of the overlying ice cap, annual cycle in vertical and horizontal movements due to ice/snow load variations, and pressure changes in the geothermal and magma plumbing systems. From 1999 to late 2004, GPS measurements including stations on nunataks within the ice cap, showed uplift and outward movement from the caldera, interpreted as inflation of the volcano due to magma inflow. InSAR time series analyzes spanning 2003-2009 show, however, no signs of detectable inflation signal around Katla. In spring 2010, two continuous GPS stations were deployed on nunataks of Katla in addition to a continuous site that has been operated since 2006. In the middle of June, 2010, a complex deformation signal started, revealing a pattern of transient deformation at the sites. Correlated fluctuations in the movements of the three GPS sites are suggested, due to a process originating from within Katla caldera. Possible explanations being explored are: i) magma chamber processes such as mixing of magma residing in volcano roots and newly arriving magma, ii) slope instability and creep causing local instability, iii) crustal stress variations imposed by ice flow at a variable rate within the overlying Mýrdalsjökull ice cap, iv) changes in water and pore pressure at the base of the ice cap, v) possible dome extrusion responding to pressure changes in the geothermal/magmatic systems in the Katla caldera. In 2011, the seismicity shows some signs of increased activity from previous years with larger events, the largest one being M3.8. A jökulhlaup, sudden glacial outburst flood, occurred 9 July 2011 was accompanied by low frequency tremor. It has been interpreted as being due to drainage of geothermal water, triggered or related to either variation in water flow conditions at the base of the ice cap, or a small magmatic event, eruption or boiling in the geothermal systems due to pressure decrease. Presently, rates of crustal deformation and earthquake activity are considerably less than observed between 1999 and 2004; nonetheless, the past year, Katla volcano has been showing some signs of increased activity.

Ofeigsson, B. G.; Hreinsdottir, S.; Sigmundsson, F.; Spaans, K.; Vogfjord, K. S.; Hooper, A. J.; Sturkell, E. C.; Roberts, M. J.; Gudmundsson, G. B.; Einarsson, P.; Arnadottir, T.; Jakobsdottir, S.; Sigurdsson, G.; Gudmundsson, M. T.; Geirsson, H.; Bennett, R. A.

2011-12-01

342

Nyiragongo Volcano, Congo, Map View with Lava, Landsat / ASTER / SRTM  

NASA Technical Reports Server (NTRS)

The Nyiragongo volcano in the Congo erupted on January 17, 2002, and subsequently sent streams of lava into the city of Goma on the north shore of Lake Kivu. More than 100 people were killed, more than 12,000 homes were destroyed, and hundreds of thousands were forced to flee the broader community of nearly half a million people. This Landsat satellite image shows the volcano (right of center), the city of Goma, and surrounding terrain. Image data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite were used to supply a partial map of the recent lava flows (red overlay), including a complete mapping of their intrusion into Goma as of January 28, 2002. Lava is also apparent within the volcanic crater and at a few other locations. Thick (but broken) cloud cover during the ASTER image acquisition prevented a complete mapping of the lava distribution, but future image acquisitions should complete the mapping.

Goma has a light pink speckled appearance along the shore of Lake Kivu. The city airport parallels, and is just right (east) of, the larger lava flow. Nyiragongo peaks at about 3,470 meters (11,380 feet) elevation and reaches almost exactly 2,000 meters (6,560 feet) above Lake Kivu. The shorter but much broader Nyamuragira volcano appears in the upper left.

Goma, Lake Kivu, Nyiragongo, Nyamuragira and other nearby volcanoes sit within the East African Rift Valley, a zone where tectonic processes are cracking, stretching, and lowering the Earth's crust. Volcanic activity is common here, and older but geologically recent lava flows (magenta in this depiction) are particularly apparent on the flanks of the Nyamuragira volcano.

The Landsat image used here was acquired on December 11, 2001, about a month before the eruption, and shows an unusually cloud-free view of this tropical terrain. Minor clouds and their shadows were digitally removed to clarify the view and topographic shading derived from the SRTM elevation model was added to the Landsat image. Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter (98-foot) resolution of most Landsat images and substantially helps in analyzing the large and growing Landsat image archive. This Landsat 7 Thematic Mapper image was provided to the SRTM and ASTER projects by the United States Geological Survey, Earth Resources Observation Systems (EROS) Data Center, Sioux Falls, S.D.

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), the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) will image Earth for several years to map and monitor the changing surface of our planet. 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. ASTER is providing scientists in numerous disciplines with critical information for surface mapping and monitoring dynamic conditions and temporal change.

Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter(approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's

2002-01-01

343

Natural Pollution Caused by the Extremely Acid Crater Lake Kawah Ijen, East Java, Indonesia (7 pp)  

Microsoft Academic Search

Background, Aims and Scope. Lakes developing in volcano craters can become highly acidic through the influx of volcanic gases, yielding one of the chemically most extreme natural environments on earth. The Kawah Ijen crater lake in East Java (Indonesia) has a pH < 0.3. It is the source of the extremely acidic and metal-polluted river Banyupahit (45 km). The lake

Ansje J. Löhr; Thom A. Bogaard; Alex Heikens; Martin R. Hendriks; Sri Sumarti; Manfred J. Van Bergen; Kees C. A. M. van Gestel; Nico van Straalen; Pieter Vroon; Budi Widianarko

2005-01-01

344

SAR4Volcanoes: an international ASI funded research project on volcano deformation through new generation SAR sensors  

NASA Astrophysics Data System (ADS)

Volcano deformation monitoring is crucial to understand how magma emplaces, propagates and erupts. Therefore, volcano deformation research projects are particularly important opportunities to improve our understanding of volcano dynamics. SAR4Volcanoes is a 2-year research project funded by the Italian Space Agency (ASI) within the framework of a cooperation agreement with the Japan Aerospace Exploration Agency (JAXA). It focuses on volcano deformation analysis through Differential SAR Interferometry (DInSAR) techniques by means of COSMO-SkyMed and ALOS data, through the joint use of L-band and X-band SAR data. It also aims to the identification of methods and techniques to support decision making in emergency cases. Main target volcanoes in the projects are Etna, Vesuvio, Campi Flegrei and Stromboli (Italy) and Sakurajima and Kirishima (Japan). Secondary target volcanoes include recently or currently erupting volcanoes, as El Hierro (Spain), Nabro (Ethiopia) and Galapagos volcanoes (Ecuador). Since the project kickoff (July 2011) a large number of COSMO-SkyMed data has been acquired at these volcanoes; in some cases, the acquisitions are available almost at every satellite orbit, with an average interval down to 4 days. On these premises, the project represents an important opportunity to: (1) collect a significant amount of X-band data on active and erupting volcanoes and (2) study surface deformation to understand magma dynamics in different volcanic settings. We will present preliminary results on the ground deformation analysis of the main and secondary target volcanoes. In particular, target volcanoes without a pre-project archive are analyzed using single deformation maps, while those with archives are analysed through a time series approach, based on the SBAS technique.

Sansosti, E.; Pepe, S.; Solaro, G.; Casu, F.; Tizzani, P.; Acocella, V.; Ruch, J.; Nobile, A.; Puglisi, G.; Guglielmino, F.; Zoffoli, S.

2012-04-01

345

Darwin's triggering mechanism of volcano eruptions  

NASA Astrophysics Data System (ADS)

Charles Darwin wrote that ‘… the elevation of many hundred square miles of territory near Concepcion is part of the same phenomenon, with that splashing up, if I may so call it, of volcanic matter through the orifices in the Cordillera at the moment of the shock;…' and ‘…a power, I may remark, which acts in paroxysmal upheavals like that of Concepcion, and in great volcanic eruptions,…'. Darwin reports that ‘…several of the great chimneys in the Cordillera of central Chile commenced a fresh period of activity ….' In particular, Darwin reported on four-simultaneous large eruptions from the following volcanoes: Robinson Crusoe, Minchinmavida, Cerro Yanteles and Peteroa (we cite the Darwin's sentences following his The Voyage of the Beagle and researchspace. auckland. ac. nz/handle/2292/4474). Let us consider these eruptions taking into account the volcano shape and the conduit. Three of the volcanoes (Minchinmavida (2404 m), Cerro Yanteles (2050 m), and Peteroa (3603 m)) are stratovolcanos and are formed of symmetrical cones with steep sides. Robinson Crusoe (922 m) is a shield volcano and is formed of a cone with gently sloping sides. They are not very active. We may surmise, that their vents had a sealing plug (vent fill) in 1835. All these volcanoes are conical. These common features are important for Darwin's triggering model, which is discussed below. The vent fill material, usually, has high level of porosity and a very low tensile strength and can easily be fragmented by tension waves. The action of a severe earthquake on the volcano base may be compared with a nuclear blast explosion of the base. It is known, that after a underground nuclear explosion the vertical motion and the surface fractures in a tope of mountains were observed. The same is related to the propagation of waves in conical elements. After the explosive load of the base. the tip may break and fly off at high velocity. Analogous phenomenon may be generated as a result of a severe earthquake. The volcano base obtains the great earthquake-induced vertical acceleration, and the compression wave begins to propagate through the volcano body. Since we are considering conic volcano, the interaction of this wave with the free surface of the volcano may be easily analysed. It is found that the reflection of the upward-going wave from the volcano slope produces tensile stresses within the volcano and bubbles in conduit magma. The conduit magma is held at high pressure by the weight and the strength of the vent fill. This fill may be collapsed and fly off , when the upward wave is reflected from the volcano crater as a decompression wave. After this collapse the pressure on the magma surface drops to atmospheric, and the decompression front begins to move downward in the conduit. In particular, large gas bubbles can begin to form in the magma within the conduit. The resulting bubble growth provides the driving force at the beginning of the eruption. Thus, the earthquake-induced nonlinear wave phenomena can qualitatively explain the spectacular simultaneity of large eruptions after large earthquakes. The pressure difference between a region of low pressure (atmosphere) and the magma chamber can cause the large-scale eruption. The beginning and the process of the eruption depend on many circumstances: conduit system and its dimension, chamber size and pressure, magma viscosity and gas concentration in it may be the main variables . The resonant free oscillations in the conduit may continue for a long time, since they are fed by the magma chamber pressure (Galiev, Sh. U., 2003. The theory of nonlinear trans-resonant wave phenomena and an examination of Charles Darwin's earthquake reports. Geophys. J. Inter., 154, 300-354.). The behaviour of the system strongly depends on the magma viscosity. The gas can escape from the bubbles more easily in the case of low viscous magma. However, if the magma is very viscous, so the gas cannot escape so easily, then the bubbles grow very quickly near the vent only. Effects of this growth can resemble an explos

Galiev, Shamil

2010-05-01

346

15. VIEW LOOKING EAST, SHOWING RETAINING WALL ON EAST SIDE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

15. VIEW LOOKING EAST, SHOWING RETAINING WALL ON EAST SIDE OF PARK, SOUTH OF ENGINE HOUSE (4' X 5' negative) - Fairmount Waterworks, East bank of Schuylkill River, Aquarium Drive, Philadelphia, Philadelphia County, PA

347

55. LOOKING EAST FROM HEAD OF PLANE 2 EAST. POWER ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

55. LOOKING EAST FROM HEAD OF PLANE 2 EAST. POWER HOUSE AND FLUME VISIBLE TO RIGHT, TAILRACE RUNNING THROUGH CENTER OF PHOTOGRAPH. CRADLE TO INCLINED PLANE 3 EAST IS VISIBLE IN BACKGROUND TO LEFT. - Morris Canal, Phillipsburg, Warren County, NJ

348

5. SOUTH AND EAST SIDES, NOTE DISTRIBUTION LINES FROM EAST ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. SOUTH AND EAST SIDES, NOTE DISTRIBUTION LINES FROM EAST WALL; VIEW TO NORTHWEST. - Cape Canaveral Air Station, Launch Complex 17, Facility 28422, East end of Lighthouse Road, Cape Canaveral, Brevard County, FL

349

Are separated volcanoes connected through a horizontal partial melt zone?  

NASA Astrophysics Data System (ADS)

The Japan Meteorological Agency installed and operates a network of Sacks-Evertson borehole strainmeters in south-east Honshu. One of these instruments is on Izu-Oshima, a volcanic island at the northern end of the Izu-Bonin arc. That strainmeter recorded large strain changes associated with the 1986 Izu-Oshima eruption. Miyake-jima, about 75 km south of Izu-Oshima, erupted in 1983. No deformation monitoring was available on Miyake but several changes occurred in the strain record at Izu-Oshima. There was a clear change in the long-term strain rate beginning 2 days before the Miyake eruption. Short period events recorded by the strainmeter occurred more frequently in the months before the Miyake eruption and ceased completely following the eruption. The Izu-Oshima strainmeter showed that, over the period from 1980 to the 1986 eruption, the amplitude of the solid earth tides changed by almost a factor of two. At the time of the Miyake eruption, the rate of increase of the tidal amplitude also changed. While all of these changes were observed on a single instrument, they are very different types of change. From a number of independent checks, we can be sure that the strainmeter did not experience any change in performance at that time. Thus it recorded a change in deformation behavior in three very different frequency bands: over very long term, at tidal periods (~day) and at very short periods (minutes). It appears that the distant eruption in 1983 had an effect on the magmatic system under Izu-Oshima. More recently, tomographic and seismic attenuation work in the Tohoku (northern Honshu) area has show the existence of a low velocity, high attenuation horizontally elongated structure under the volcanic front. It is likely that this is a zone of partial melt and that this zone is a supply of magma for the volcanic activity. The tectonic setting for Miyake-jima and Izu-Oshima is very similar to that for Tohoku and we expect that these volcanoes are also underlain by a low Q, low velocity (i.e. partial melt) zone. If so, it could provide a mechanism for communication between the volcanoes.

Linde, A.; Sacks, S.; Kamigaichi, O.

2003-04-01

350

Origin of maar volcanoes: external water, internal volatiles, or both?  

NASA Astrophysics Data System (ADS)

The origin of maar volcanoes has been interpreted as due to explosive magma-water interaction for more than 40 years (Fisher and Waters 1970; Lorenz 1973 and Fisher and Schmincke 1984). Earlier suspicions that CO2-degassing plays a role in maar formation (Schmincke 1977) are now followed up by re-examining maar deposits of four different compositions in the maar-type locality (Eifel, Germany). These four compositions comprise: (1) melilite-nephelinites (West Eifel), (2) leucitites/nephelinites (West Eifel), (3) Na-rich basanites (West Eifel), and (4) K-rich basanites (East Eifel). At present, we focus on high-resolution stratigraphy, sedimentology, grain-size distribution, component analysis (accidental vs. juvenile clasts), and morphological and textural particle studies, accompanied by standard glass and bulk chemical and mineralogical analyses. Interestingly, maar deposits of highly silica-undersaturated and - by inference - CO2-rich composition (melilite-nephelinites and leucitites/nephelinites) show features contrasting with the classical catalogue of criteria for hydroclastic fragmentation (Fisher and Schmincke 1984). Their deposits are medium- to coarse-grained (MdØ mainly: 2 - 8 mm), mostly moderate- to well-sorted (?Ø mainly: 1 - 2.5) and in some cases juvenile-rich (up to 50-70 wt. %). Transport and depositional mechanisms comprise a mixture of surge and fallout differing from the general assumption that maar deposits are dominated by surges. Additionally, features of juvenile clasts of highly silica-undersaturated composition largely differ from the features of "classic" hydroclastic particles (e.g.: dense, blocky, glassy shards). Juvenile clasts of highly silica-undersaturated composition show: (a) round- to semiround morphologies, (b) slight- to moderate vesicularities, (c) near absence of glassy material, (d) abundance of deep-seated xenoliths (mantle and lower crust), (e) agglutinated lava rinds enveloping the mantle- and crust-xenoliths, and (f) carbonate fragments, most probably of magmatic origin, within the groundmass. In contrast, basanitic maar deposits - by inference with low CO2 concentrations - and particularly their juvenile clasts show more conventional features of hydroclastic fragmentation processes. They are finer-grained, moderate- to poorly-sorted, extremely lithoclast-rich, and the juvenile clasts are generally angular, slightly- to non-vesicular and glassy. Moreover, deep-seated xenoliths and carbonate fragments are lacking. At this stage in our study we postulate that the high CO2 concentrations of highly silica-undersaturated maar volcanoes in the West Eifel could have played a significant role in maar-forming processes. These magmas may have undergone magmatic fragmentation due to rapid CO2-exsolution prior to shallow magma-water interaction resulting in explosive eruptions governed by both, magmatic and phreatomagmatic fragmentation and eruptive processes.

Rausch, J.; Schmincke, H.-U.

2012-04-01

351

Volcanoes in the Solar System Pictorial Tour  

NSDL National Science Digital Library

Volcanoes in the Solar System is a Windows to the Universe Exploratour and provides information and images about shield volcanoes, cinder cones, ash, lava, Venus, Mars, Jupiter, Io, and the Moon. Windows to the Universe is a user-friendly learning system pertaining to the Earth and Space sciences. The objective of this project is to develop an innovative and engaging web site that spans the Earth and Space sciences and includes a rich array of documents, including images, movies, animations, and data sets that explore the Earth and Space sciences and the historical and cultural ties between science, exploration and the human experience. Links at the top of each page allow users to navigate between beginner, intermediate, and advanced options for each topic level.

Roberta Johnson

2000-07-01

352

How Volcanoes Work: Dynamics of Eruptions  

NSDL National Science Digital Library

This site examines the variability of volcanic environments and the physical and chemical controls on eruption dynamics. Environments of volcanism are discussed in terms of plate tectonic theory and include spreading center, subduction zone, and interplate volcanism along with a detailed discussion of the Earth's structure and internal heat. Physical and chemical controls of eruption dynamics include composition of the magma and also its viscosity, temperature, and the amount of dissolved gases in the magma. The section on eruption variability includes a discussion about the frequency and size of the eruptions as well as a detailed explanation of Volcano Explosivity Index, (VEI) and also includes a chart that compares the VEI of well-known volcanoes. This site also has an eruption model that explains the dynamics of the eruption with diagrams. An interactive quiz is included that gives immediate feed-back.

Victor Camp

353

Learning to Recognize Volcanoes on Venus  

E-print Network

Dramatic improvements in sensor and image acquisition technology have created a demand for automated tools that can aid in the analysis of large image databases. We describe the development of JARtool, a trainable software system that learns to recognize volcanoes in a large data set of Venusian imagery. A machine learning approach is used because it is much easier for geologists to identify examples of volcanoes in the imagery than it is to specify domain knowledge as a set of pixellevel constraints. This approach can also provide portability to other domains without the need for explicit reprogramming; the user simply supplies the system with a new set of training examples. We show how the development of such a system requires a completely different set of skills than are required for applying machine learning to "toy world" domains. This paper discusses important aspects of the application process not commonly encountered in the "toy world," including obtaining labeled training d...

Michael C. Burl; Lars Asker; Padhraic Smyth; Usama Fayyad; Pietro Perona; Larry Crumpler; Jayne Aubele

1998-01-01

354

Automating the Hunt for Volcanoes on Venus  

E-print Network

Our long-term goal is to develop a trainable tool for locating patterns of interest in large image databases. Toward this goal we have developed a prototype system, based on classical filtering and statistical pattern recognition techniques, for automatically locating volcanoes in the Magellan SAR database of Venus. Training for the specific volcano-detection task is obtained by synthesizing feature templates (via normalization and principal components analysis) from a small number of examples provided by experts. Candidate regions identified by a focus of attention (FOA) algorithm are classified based on correlations with the feature templates. Preliminary tests show performance comparable to trained human observers. 1 Introduction Many geological studies use surface features to deduce processes that have occurred on a planet. The recent JPL Magellan mission, which was successful in imaging over 95% of the surface of Venus with synthetic aperture radar (SAR), has provided planetary s...

M.P. Burl; U. M. Fayyad; P. Perona; P. Smyth

1994-01-01

355

Mud volcanism: Processes and implications Mud volcanoes: generalities and proposed mechanisms  

E-print Network

Editorial Mud volcanism: Processes and implications Mud volcanoes: generalities and proposed mechanisms Mud volcanoes can be large and long lived geological structures that morphologically resemble magmatic volcanoes. Because of their capricious behaviour and their spectacular morphology and landscapes

Manga, Michael

356

The Anatahan volcano-monitoring system  

Microsoft Academic Search

A real-time 24\\/7 Anatahan volcano-monitoring and eruption detection system is now operational. There had been no real-time seismic monitoring on Anatahan during the May 10, 2003 eruption because the single telemetered seismic station on Anatahan Island had failed. On May 25, staff from the Emergency Management Office (EMO) of the Commonwealth of the Northern Mariana Islands and the U. S.

J. N. Marso; A. B. Lockhart; R. A. White; S. K. Koyanagi; F. A. Trusdell; J. T. Camacho; R. Chong

2003-01-01

357

Buried caldera of mauna kea volcano, hawaii.  

PubMed

An elliptical caldera (2.1 by 2.8 kilometers) at the summit of Mauna Kea volcano is inferred to lie buried beneath hawaiite lava flows and pyroclastic cones at an altitude of approximately 3850 meters. Stratigraphic relationships indicate that hawaiite eruptions began before a pre-Wisconsin period of ice-cap glaciation and that the crest of the mountain attained its present altitude and gross form during a glaciation of probable Early Wisconsin age. PMID:17842285

Porter, S C

1972-03-31

358

Radar Images of the Earth: Volcanoes  

NSDL National Science Digital Library

This site features links to thirty-five NASA radar images of the world's volcanoes, including brief descriptions of the respective processes and settings involved. The images were created with the Spaceborne Imaging Radar-C and X-Band Synthetic Aperture Radar (SIR-C/X-SAR) as part of NASA's Mission to Planet Earth. The radar illuminates Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions.

359

Active volcanoes guided Tsunamigenic earthquakes from Andaman –  

E-print Network

The Indian Ocean Tsunami of Northern Sumatra Great Earthquake disastrous event (Mw 9.3) on 26th December 2004, had initiated release of trains of aftershocks in different directions. The above events resulted in explosions of series of Volcanoes of Andaman and Indonesian Island Arc Belt. After the tsunamigenic Northern Sumatra Great Earthquake of 2004, consecutive many tsunamigenerations were formed from the following regions viz West

unknown authors

360

Volcanism in Iceland in historical time: Volcano types, eruption styles and eruptive history  

NASA Astrophysics Data System (ADS)

The large-scale volcanic lineaments in Iceland are an axial zone, which is delineated by the Reykjanes, West and North Volcanic Zones (RVZ, WVZ, NVZ) and the East Volcanic Zone (EVZ), which is growing in length by propagation to the southwest through pre-existing crust. These zones are connected across central Iceland by the Mid-Iceland Belt (MIB). Other volcanically active areas are the two intraplate belts of Öræfajökull (ÖVB) and Snæfellsnes (SVB). The principal structure of the volcanic zones are the 30 volcanic systems, where 12 are comprised of a fissure swarm and a central volcano, 7 of a central volcano, 9 of a fissure swarm and a central domain, and 2 are typified by a central domain alone. Volcanism in Iceland is unusually diverse for an oceanic island because of special geological and climatological circumstances. It features nearly all volcano types and eruption styles known on Earth. The first order grouping of volcanoes is in accordance with recurrence of eruptions on the same vent system and is divided into central volcanoes (polygenetic) and basalt volcanoes (monogenetic). The basalt volcanoes are categorized further in accordance with vent geometry (circular or linear), type of vent accumulation, characteristic style of eruption and volcanic environment (i.e. subaerial, subglacial, submarine). Eruptions are broadly grouped into effusive eruptions where >95% of the erupted magma is lava, explosive eruptions if >95% of the erupted magma is tephra (volume calculated as dense rock equivalent, DRE), and mixed eruptions if the ratio of lava to tephra occupy the range in between these two end-members. Although basaltic volcanism dominates, the activity in historical time (i.e. last 11 centuries) features expulsion of basalt, andesite, dacite and rhyolite magmas that have produced effusive eruptions of Hawaiian and flood lava magnitudes, mixed eruptions featuring phases of Strombolian to Plinian intensities, and explosive phreatomagmatic and magmatic eruptions spanning almost the entire intensity scale; from Surtseyan to Phreatoplinian in case of "wet" eruptions and Strombolian to Plinian in terms of "dry" eruptions. In historical time the magma volume extruded by individual eruptions ranges from ˜1 m 3 to ˜20 km 3 DRE, reflecting variable magma compositions, effusion rates and eruption durations. All together 205 eruptive events have been identified in historical time by detailed mapping and dating of events along with extensive research on documentation of eruptions in historical chronicles. Of these 205 events, 192 represent individual eruptions and 13 are classified as "Fires", which include two or more eruptions defining an episode of volcanic activity that lasts for months to years. Of the 159 eruptions verified by identification of their products 124 are explosive, effusive eruptions are 14 and mixed eruptions are 21. Eruptions listed as reported-only are 33. Eight of the Fires are predominantly effusive and the remaining five include explosive activity that produced extensive tephra layers. The record indicates an average of 20-25 eruptions per century in Iceland, but eruption frequency has varied on time scale of decades. An apparent stepwise increase in eruption frequency is observed over the last 1100 years that reflects improved documentation of eruptive events with time. About 80% of the verified eruptions took place on the EVZ where the four most active volcanic systems (Grímsvötn, Bárdarbunga-Veidivötn, Hekla and Katla) are located and 9%, 5%, 1% and 0.5% on the RVZ-WVZ, NVZ, ÖVB, and SVB, respectively. Source volcano for ˜4.5% of the eruptions is not known. Magma productivity over 1100 years equals about 87 km 3 DRE with basaltic magma accounting for about 79% and intermediate and acid magma accounting for 16% and 5%, respectively. Productivity is by far highest on the EVZ where 71 km 3 (˜82%) were erupted, with three flood lava eruptions accounting for more than one half of that volume. RVZ-WVZ accounts for 13% of the magma and the NWZ and the

Thordarson, T.; Larsen, G.

2007-01-01

361

Tharsis Volcanoes and Valles Marineris, Mars  

NASA Technical Reports Server (NTRS)

It is northern summer on Mars and clouds are very common over the famous Tharsis volcanoes during the afternoon. At the far left, a white patchy cloud denotes the location of Olympus Mons. Ascraeus Mons is under the brightest cloud toward the center left, but the volcanoes Pavonis Mons and Arsia Mons (toward lower left below Ascraeus Mons) have much less cloud cover. The patch of clouds toward the upper left mark the location of the Alba Patera volcano. The Valles Marineris trough system--so long that it would stretch across North America--is seen in the lower third of this picture. This is a color composite of 9 red and 9 blue image strips taken by the Mars Global Surveyor Mars Orbiter Camera on 9 successive orbits from pole-to-pole during the calibration phase of the mission in March 1999. The color is computer-enhanced and is not shown as it would actually appear to the human eye.

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.

1999-01-01

362

Electrical structure of Newberry Volcano, Oregon  

USGS Publications Warehouse

From the interpretation of magnetotelluric, transient electromagnetic, and Schlumberger resistivity soundings, the electrical structure of Newberry Volcano in central Oregon is found to consist of four units. From the surface downward, the geoelectrical units are 1) very resistive, young, unaltered volcanic rock, (2) a conductive layer of older volcanic material composed of altered tuffs, 3) a thick resistive layer thought to be in part intrusive rocks, and 4) a lower-crustal conductor. This model is similar to the regional geoelectrical structure found throughout the Cascade Range. Inside the caldera, the conductive second layer corresponds to the steep temperature gradient and alteration minerals observed in the USGS Newberry 2 test-hole. Drill hole information on the south and north flanks of the volcano (test holes GEO N-1 and GEO N-3, respectively) indicates that outside the caldera the conductor is due to alteration minerals (primarily smectite) and not high-temperature pore fluids. On the flanks of Newberry the conductor is generally deeper than inside the caldera, and it deepens with distance from the summit. A notable exception to this pattern is seen just west of the caldera rim, where the conductive zone is shallower than at other flank locations. The volcano sits atop a rise in the resistive layer, interpreted to be due to intrusive rocks. -from Authors

Fitterman, D.V.; Stanley, W.D.; Bisdorf, R.J.

1988-01-01

363

Deep structure of Medicine Lake volcano, California  

USGS Publications Warehouse

Medicine Lake volcano (MLV) in northeastern California is the largest-volume volcano in the Cascade Range. The upper-crustal structure of this Quaternary shield volcano is well known from previous geological and geophysical investigations. In 1981, the U.S. Geological Survey conducted a teleseismic tomography experiment on MLV to explore its deeper structure. The images we present, calculated using a modern form of the ACH-inversion method, reveal that there is presently no hint of a large (> 100 km3), hot magma reservoir in the crust. The compressional-wave velocity perturbations show that directly beneath MLV's caldera there is a zone of increased seismic velocity. The perturbation amplitude is +10% in the upper crust, +5% in the lower crust, and +3% in the lithospheric mantle. This positive seismic velocity anomaly presumably is caused by mostly subsolidus gabbroic intrusive rocks in the crust. Heat and melt removal are suggested as the cause in the upper mantle beneath MLV, inferred from petro-physical modeling. The increased seismic velocity appears to be nearly continuous to 120 km depth and is a hint that the original melts come at least partly from the lower lithospheric mantle. Our second major finding is that the upper mantle southeast of MLV is characterized by relatively slow seismic velocities (-1%) compared to the northwest side. This anomaly is interpreted to result from the elevated temperatures under the northwest Basin and Range Province.

Ritter, J.R.R.; Evans, J.R.

1997-01-01

364

Seismic Tomography of Erebus Volcano, Antarctica  

NASA Astrophysics Data System (ADS)

Mount Erebus (77°32'S, 167°10'E elevation 3794 meters) is the most active volcano in Antarctica and is well known for its persistent lava lake. The lake constitutes an “open window” into the conduit and underlying feeding system and offers a rare opportunity to observe a shallow convecting magmatic system. Imaging and modeling of the internal structure of Erebus volcano are best done through compiling information from arrays of seismometers positioned strategically around the volcano. From these data, the three-dimensional (3-D) structure of the conduit can be pieced together. Building this 3-D model of Erebus was a main goal of the seismic tomographic experiment Tomo Erebus (TE). During the 2007-2008 austral field season, 23 intermediate-period seismometers were installed to contribute data, through the winter, for the passive-source aspect of the experiment. One year later, 100 three-component short-period stations were deployed to record 16 chemical blasts (see Figure 1).

Zandomeneghi, Daria; Kyle, Philip; Miller, Pnina; Snelson, Catherine; Aster, Richard

2010-02-01

365

Detecting Blackholes and Volcanoes in Directed Networks  

E-print Network

In this paper, we formulate a novel problem for finding blackhole and volcano patterns in a large directed graph. Specifically, a blackhole pattern is a group which is made of a set of nodes in a way such that there are only inlinks to this group from the rest nodes in the graph. In contrast, a volcano pattern is a group which only has outlinks to the rest nodes in the graph. Both patterns can be observed in real world. For instance, in a trading network, a blackhole pattern may represent a group of traders who are manipulating the market. In the paper, we first prove that the blackhole mining problem is a dual problem of finding volcanoes. Therefore, we focus on finding the blackhole patterns. Along this line, we design two pruning schemes to guide the blackhole finding process. In the first pruning scheme, we strategically prune the search space based on a set of pattern-size-independent pruning rules and develop an iBlackhole algorithm. The second pruning scheme follows a divide-and-conquer strategy to fur...

Li, Zhongmou; Liu, Yanchi

2010-01-01

366

Citizen Empowerment in Volcano Monitoring, Communication and Decision-Making at Tungurahua Volcano, Ecuador  

NASA Astrophysics Data System (ADS)

Trained citizen volunteers called vigías have worked to help monitor and communicate warnings about Tungurahua volcano, in Ecuador, since the volcano reawoke in 1999. The network, organized by the scientists of Ecuacor's Instituto Geofísico de la Escuela Politécnica Nacional (Geophysical Institute) and the personnel from the Secretaría Nacional de Gestión de Riesgos (Risk Management, initially the Civil Defense), has grown to well over 20 observers living around the volcano who communicate regularly via handheld two-way radios. Interviews with participants in 2010 indicate that the network enables direct communication between communities and authorities, engenders trust in scientists and emergency response personnel, builds community, and empowers communities to make decisions in times of crisis.

Bartel, B.; Mothes, P. A.

2013-05-01

367

Citizen empowerment in volcano monitoring, communication and decision-making at Tungurahua volcano, Ecuador  

NASA Astrophysics Data System (ADS)

Trained citizen volunteers called vigías have worked to help monitor and communicate warnings about Tungurahua volcano, in Ecuador, since the volcano reawoke in 1999. The network, organized by the scientists of Ecuador's Instituto Geofísico de la Escuela Politécnica Nacional (Geophysical Institute) and the personnel from the Secretaría Nacional de Gestión de Riesgos (Risk Management, initially the Civil Defense), has grown to more than 20 observers living around the volcano who communicate regularly via handheld two-way radios. Interviews with participants conducted in 2010 indicate that the network enables direct communication between communities and authorities; engenders trust in scientists and emergency response personnel; builds community; and empowers communities to make decisions in times of crisis.

Bartel, B. A.; Mothes, P. A.

2013-12-01

368

A Teachers Guide to the Geology of Hawaii Volcanoes National Park  

NSDL National Science Digital Library

This guide is designed for teachers, other educators, and anyone interested in volcanoes. Topics covered by this guide include plate tectonics, hot spots and mantle plumes, the evolution of Hawaiian volcanoes, volcanic landforms, landforms of Hawaii Volcanoes National Park, lava, tephra, calderas, pit craters, minerals, magma, volcanic rocks, monitoring volcanoes, eruption types and details about Kilauea. Although the guide focuses on Hawaiian volcanoes, similar processes and features are observed at volcanoes around the world.

Stephen Mattox

369

Fumarole/plume and diffuse CO2 emission from Sierra Negra volcano, Galapagos archipelago  

NASA Astrophysics Data System (ADS)

The active shield-volcano Sierra Negra is part of the Galapagos hotspot. Sierra Negra is the largest shield volcano of Isabela Island, hosting a 10 km diameter caldera. Ten historic eruptions have occurred and some involved a frequently visited east caldera rim fissure zone called Volcan Chico. The last volcanic event occurred in October 2005 and lasted for about a week, covering approximately twenty percent of the eastern caldera floor. Sierra Negra volcano has experienced some significant changes in the chemical composition of its volcanic gas discharges after the 2005 eruption. This volcanic event produced an important SO2 degassing that depleted the magmatic content of this gas. Not significant changes in the MORB and plume-type helium contribution were observed after the 2005 eruption, with a 65.5 % of MORB and 35.5 % of plume contribution. In 2006 a visible and diffuse gas emission study was performed at the summit of Sierra Negra volcano, Galapagos, to evaluate degassing rate from this volcanic system. Diffuse degassing at Sierra Negra was mainly confined in three different DDS: Volcan Chico, the southern inner margin of the caldera, and Mina Azufral. These areas showed also visible degassing, which indicates highly fractured areas where volcano-hydrothermal fluids migrate towards surface. A total fumarole/plume SO2 emission of 11 ± 2 td-1 was calculated by mini-DOAS ground-based measurements at Mina Azufral fumarolic area. Molar ratios of major volcanic gas components were also measured in-situ at Mina Azufral with a portable multisensor. The results showed H2S/SO2, CO2/SO2 and H2O/SO2 molar ratios of 0.41, 52.2 and 867.9, respectively. Multiplying the observed SO2 emission rate times the observed (gas)i/SO2 mass ratio we have estimated other volatiles emission rates. The results showed that H2O, CO2 and H2S emission rates from Sierra Negra are 562, 394, and 2.4 t d-1, respectively. The estimated total output of diffuse CO2 emission from the summit of Sierra Negra was 989 ± 85 t d-1. Estimated diffuse/plume CO2 emission ratio was 2.5.

Padron, E.; Hernandez Perez, P. A.; Perez, N.; Theofilos, T.; Melian, G.; Barrancos, J.; Virgil, G.; Sumino, H.; Notsu, K.

2009-12-01

370

Magma Composition, Dynamics and Eruption Frequency at Katla Volcano, Iceland: a Holocene Tephra Layer Record  

NASA Astrophysics Data System (ADS)

The Katla volcano in Iceland is characterized by subglacial explosive eruptions of Fe-Ti basalt composition. Its historical activity has been thoroughly studied as well as the major element composition of the erupted products. The long term evolution of Katla's volcanic activity and magma production is less well known. A study of the tephra stratigraphy east of the volcano has been undertaken in a composite soil section with main focus on the prehistoric part. The section records 8400 years of explosive activity from Katla volcano and includes 208 tephra layers of which 126 samples were analysed for major-element composition. The age of individual Katla layers was calculated using soil accumulation rates (SAR) derived from soil thicknesses between 14C-dated marker tephra layers. Temporal variations in major-element compositions of the basaltic tephra divide the 8400 year record into eight intervals of 510-1750 year durations. The change in concentration of incompatible elements (i.e., K2O) in individual intervals is characterized as steady, irregular and steadily increasing. These variations in incompatible elements correlate with changes in other major-element concentrations and suggest that the magmatic evolution beneath Katla is primarily controlled by fractional crystallisation. In addition, binary mixing between basaltic component and a silicic melt is inferred for several tephra layers. Small eruptions of silicic (SILK) tephra occur throughout the Holocene, but these events do not appear to exhibit strong influence on the magmatic evolution of the basalts. It is worth noting, however, that the peaks in the frequency of basaltic and silicic eruptions are contemporaneous. The observed pattern of change in tephra composition within individual time intervals suggests different conditions in the plumbing system beneath Katla volcano. Two cycles are observed throughout the Holocene, each involving three stages of plumbing system evolution. A cycle begins with a simple plumbing system, as indicated by a steady state in major element compositions. This is followed by a sill and dyke system, a period that is characterized by irregular variations in major element composition with time, and eventually leads to the formation of a magma chamber, represented by a uniform increasing in incompatible elements. The eruption frequency within each cycle increases from the stage of a simple plumbing system to the sill and dyke complex stage and then drops again during magma chamber stage. In accordance with this model, the Katla volcano is at present in a stage of a simple plumbing system characterized by steady state magma composition and relatively low eruption frequency.

Oladottir, B. A.; Sigmarsson, O.; Larsen, G.; Thordarson, T.

2006-12-01

371

Origin and evolution of valleys on Martian volcanoes  

NASA Technical Reports Server (NTRS)

Medium (1:2,000,000) and high (1:500,000) resolution Viking images were used to locate, map, and analyze drainage systems of six moderate-sized Martian volcanoes 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 volcanoes. 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 volcanoes, an evolutionary sequence for valleys on the Martian volcanoes is proposed.

Gulick, Virginia C.; Baker, Victor R.

1990-01-01

372

Mud volcanoes of the Orinoco Delta, Eastern Venezuela  

USGS Publications Warehouse

Mud volcanoes 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 volcanoes 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 volcanoes 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 volcano sediment is derived from underlying Miocene and Pliocene strata. Hydrocarbon seeps are associated with several of the active mud volcanoes. Orinoco mud volcanoes overlie the crest of a mud-diapir-cored anticline located along the axis of the Eastern Venezuelan Basin. Faulting along the flank of the Pedernales mud volcano suggests that fluidized sediment and hydrocarbons migrate to the surface along faults produced by tensional stresses along the crest of the anticline. Orinoco mud volcanoes 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 volcanoes 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.

Aslan, A.; Warne, A.G.; White, W.A.; Guevara, E.H.; Smyth, R.C.; Raney, J.A.; Gibeaut, J.C.

2001-01-01

373

Volcano Expedition: From the Field in Costa Rica  

NSDL National Science Digital Library

This resource offers, among other things, a collection of journal entries from scientists reporting on their personal experiences of the volcanoes of Costa Rica. Reference sections include an introduction to volcanoes and Central America, the anatomy of subduction zones, the source of volatiles, sampling volatiles, recycling elements, and isotope geochemistry (geochemical tracers). There is a short description of several Costa Rican volcanoes, including: Turrialba, Arenal, Irazu, Poas, Rincon de la Vieja, Miravalles, and Laguna Poco Sol. Also included are a question and answer section on volcanoes, details about the expedition, and safety and danger issues.

374

July 1973 ground survey of active Central American volcanoes  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. Ground survey has shown that thermal anomalies of various sizes associated with volcanic activity at several Central American volcanoes should be detectable from Skylab. Anomalously hot areas of especially large size (greater than 500 m in diameter) are now found at Santiaguito and Pacaya volcanoes in Guatemala and San Cristobal in Nicaragua. Smaller anomalous areas are to be found at least seven other volcanoes. This report is completed after ground survey of eleven volcanoes and ground-based radiation thermometry mapping at these same points.

Stoiber, R. E. (principal investigator); Rose, W. I., Jr.

1973-01-01

375

Prospects of Volcano Geodesy with ERS Radar Interferometry  

E-print Network

ABSTRACT: Since the detection of surface deformation at Mt. Etna it was believed that space-borne radar interferometry may provide a tool to monitor most of the Earth's active volcanoes. We have studied a large number of volcanoes from different environments and show that ERS C-band radar interferometry can be used only to observe certain volcanoes with particular conditions. The best targets for ERS C-band interferometry are shield volcanoes and large calderas. Stratovolcanoes are less suited for radar interferometric observations due to geometric distortions and severe environmental conditions. Interferometric coherence is often lost because of snow coverage and ash deposits.

Falk Amelung; Sigurjon Jonsson; Howard Zebker; Paul Segall

376

Erosion and aggradation on persistently active volcanoes—a case study from Semeru Volcano, Indonesia  

NASA Astrophysics Data System (ADS)

Erosion processes on active volcanoes in humid climates result in some of the highest sediment yields on Earth. Episodic sediment yields after large eruptions have been evaluated, but not the long-term and continuous patterns on persistently active volcanoes. We have used high-spatial resolution satellite imagery and DEMs/DSMs along with field-based geologic mapping to assess accurately sediment budgets for the active Semeru Volcano in Java, Indonesia. Patterns of aggradation and degradation on Semeru differ from that of other active volcanoes because (1) both episodic pyroclastic density currents (PDC) and continuous supplies of tephra generate pulses of sediment, (2) sediment is transferred via cycles of aggradation and degradation that continue for >15 years in river channels after each PDC-producing eruption, and (3) rain-triggered lahars remove much greater material than fluvial transport during long, intense rainfall events. The geomorphic response of two of Semeru's rivers to volcanic sediment migration indicates that (1) each river experiences alternating aggradation and degradation cycles following PDC-producing eruptions and (2) spatial patterns of sediment transfer are governed by geomorphic characteristics of the river reaches. Usually high degradation in the steep source reach is followed by a long bypassing middle reach. Aggradation predominates in the depositional reaches further down valley on the ring plain. Average sediment yields (103-105 t/km2/year) at persistently active volcanoes are two to three orders of magnitude lower than sediment yields after large and infrequent eruptions, but the continuous and steady sediment transfer in rivers removes more sediment on a mid-term (10 years) to long-term (30 years) basis. In contrast to the trend observed on composite cones after large and infrequent eruptions, decay of sediment yields is not exponential and river channels do not fully recover at steadily active volcanoes as episodic inputs from BAF eruptions, superimposed on the background remobilization of daily tephra, have a greater cumulative effect.

Thouret, Jean-Claude; Oehler, Jean-François; Gupta, Avijit; Solikhin, Akhmad; Procter, Jonathan N.

2014-10-01

377

An Experimental Contribution to the Dynamics of Explosive Volcanism. A Case Study of Unzen Volcano and Soufrière Hills Volcano, Montserrat  

Microsoft Academic Search

Knowledge of the dynamics of magma fragmentation is necessary for a better understanding of the explosive behavior of silicic volcanoes. Here we have measured the fragmentation speed and the fragmentation threshold of five dacitic field samples (6.7 vol.% to 53.5 vol.% open porosity) from Unzen volcano, Kyushu, Japan and four andesitic-dacitic field samples of Soufrière Hills Volcano, Montserrat, West Indies

B. Scheu; O. Spieler; D. B. Dingwell

2003-01-01

378

Fluid-volcano interaction in an active stratovolcano: the crater lake system of Poás volcano, Costa Rica  

Microsoft Academic Search

Rowe, G.L. Jr., Brantley, S.L., Fernandez, M., Fernandez, J.F., Borgia, A. and Barquero, J., 1992. Fluid-volcano interac- tion in an active stratovolcano: the crater lake system of Po~is volcano, Costa Rica. J. Volcanol. Geotherm. Res., 49: 23- 51. Seismic and geochemical data collected at Po~is volcano, Costa Rica, since 1978 suggest that temperature and chemical variations recorded in subaerial fumaroles

G ROWEJR; Susan L. Brantley; Mario Fernandez; Jose F. Fernandez; Andrea Borgia; Jorge Barquero

1992-01-01

379

In Brief: U.S. Volcano Early Warning System; Bill provides clear mandate for NOAA  

NASA Astrophysics Data System (ADS)

The U.S. Geological Survey on 29 April released a comprehensive review of the 169 U.S. volcanoes, and established a framework for a National Volcano Early Warning System that is being formulated by the Consortium of U.S. Volcano Observatories. The framework proposes an around-the-clock Volcano Watch Office and improved instrumentation and monitoring at targeted volcanoes. The report, authored by USGS scientists John Ewert, Marianne Guffanti, and Thomas Murray, notes that although a few U.S. volcanoes are well-monitored, half of the most threatening volcanoes are monitored at a basic level and some hazardous volcanoes have no ground-based monitoring.

Showstack, Randy

2005-05-01

380

Magma-tectonic interactions at Kilauea volcano revealed by the modeling of geodetic and seismic data  

NASA Astrophysics Data System (ADS)

InSAR (Interferometric Synthetic Aperture Radar) provides high-spatial-resolution measurements of surface deformation with centimeter-scale accuracy. At Kilauea Volcano, Hawai'i, volcano-tectonic earthquakes (VTs) occur in conjunction with stronger tectonic earthquakes due to interaction between existing fault structures and magmatic and tectonic processes. In particular, Kilauea's southern flank is sliding seaward along a large crustal detachment fault (décollement), located at the interface between the volcano and the preexisting ocean floor at about 9-12 km depth, that occasionally produces large-magnitude and destructive earthquakes. In contrast, swarms of low-magnitude earthquakes (east rift zones (SWRZ and ERZ, respectively) due to magma storage and transport within a few kilometers of the surface. The most common mode of failure in the upper east rift zone (UERZ) appears to be strike slip faulting. There are two main directions for the P-axes, ~NW-SE or ~NW-SE, and this variation might be induced by the summit area's deformation behavior. Here, we apply conventional InSAR and the 'StaMPS' ('Stanford Method for Permanent Scatterers') technique, which incorporates both persistent scatterer and small baseline approaches, to RADARSAT-1, ENVISAT and ALOS data spanning 2000 to 2010, to analyze the deformation behavior of Kilauea's southwest rift zone (SWRZ) and in the summit area. The SWRZ 'background deformation' is characterized by broad subsidence of a few cm/yr, except during periods of magma accumulation in the subsurface. Based on daily GPS solutions, we define three 'background deformation' periods, during which no abnormal eruptive activity or unrest influences the deformation behavior of the SWRZ. The first period spans July 2000 to September 2003 and is covered by a highly coherent RADARSAT-1 interferogram. The second background period spans October 2006 to March 2007, just a few months before an east rift zone intrusion and eruption in June 2007. The third period spans December 2009 to June 2010. We speculate that broad SWRZ subsidence is caused by the same processes that trigger subsidence of Kilauea's east rift zone - namely deep rift opening and basal fault slip. A 3D Mixed-Boundary Element model including deep rift-zone opening (running from ~3 to 9 km depth beneath Kilauea's east and southwest rift zones) as well as slip on the décollement fault that underlies the volcano's south flank (at ~9km depth) can explain broad SWRZ deformation imaged from RADARSAT-1 data for the first background period. This model will be refined by inversions and compared to simpler kinematic analytical models involving distributed Okada, and tested against the other background deformation periods. In addition, we will include seismic data to help constrain the models.

Wauthier, C.; Roman, D. C.; Poland, M. P.; Miklius, A.; Hooper, A. J.; Fukushima, Y.; Cayol, V.

2013-12-01

381

Evidence for magma mingling at Newberry Volcano, Oregon  

NASA Astrophysics Data System (ADS)

The ~0.3-Ma tuff of Tepee Draw (Qtp) records the earliest caldera-forming eruption of Newberry Volcano, a voluminous, subduction-related central volcano, located 60 km east of the main axis of the Cascade arc in central Oregon. Whole-rock analyses indicate that single pumices from Qtp are andesite to low-silica rhyolite (62.3-72.6 wt. % SiO2; anhydrous). While most of the rhyolitic pumices are homogeneous, the less evolved pumices display conspicuous banding. Constituting <1% of outcrops, the banded pumices have varying amounts (up to 60%) of dark brown to black glass intermingled with light gray to tan glass. Crenulate margins and fluidal textures evident in hand samples indicate liquid-liquid interaction. Based on electron microprobe analyses (EMPA), the light-colored glass is rhyolitic in composition (anhydrous avg.=72.9 wt. % SiO2; ?=0.52, n=59), whereas preliminary results suggest that the dark-colored glass is andesitic (anhydrous avg.=60.8 wt. % SiO2; ?=3.9, n=18). In addition to fluidal textures, EMPA of minerals from representative pumices throughout the compositional range provide further evidence for magma mingling. Particularly, analyses of plagioclase, pyroxene, and olivine phenocrysts define two distinct populations, representing discrete magma compositions. As the predominant phase in Qtp pumices, plagioclase phenocrysts are subdivided into calcic (An60.1-84.3) and sodic (An20.4-44.1) groups. Calcic varieties are typically fresh appearing, but some crystals are highly corroded. Sodic phenocrysts are commonly euhedral with minimal resorption. Banded pumices contain both calcic and sodic plagioclase although their modal proportions vary with whole-rock silica content; sodic varieties only occur in the homogeneous rhyolite pumices. Qtp pumices also contain subordinate amounts of clinopyroxene and orthopyroxene. In general, pyroxene phenocrysts are euhedral to subhedral, though some crystals have minor embayments. Two compositional groups have been identified based on Mg content, and their occurrence is dependent on host pumice type. Pyroxenes in the banded pumices are higher-Mg augite (En44.1-49.1) and enstatite (En65.7-70.8), while those in the homogeneous rhyolite pumices are lower-Mg augite (En25.9-29.8) and enstatite (En55.9). Additionally, Qtp pumices include two types of olivine phenocrysts. Forsteritic olivine (Fo70.3-81.0) only occurs in the mafic portions of the banded pumices, whereas fayalitic olivine (Fo21.6-22.3) is found in both the rhyolitic portions of the banded pumices and within the homogeneous rhyolite pumices. The larger forsterite phenocrysts are subhedral to anhedral with some embayments; the smaller crystals are euhedral to subhedral and intact. Fayalite is euhedral to subhedral and appears fresh with slight oxidation evident in some crystals. This study documents magma mingling in one of the oldest ash-flow tuffs related to Newberry Volcano. The lack of reaction rims associated with the forsteritic olivine and Mg-rich pyroxene phenocrysts indicates that the more mafic magma was probably not in contact with the rhyolitic magma for a protracted period of time. As such, injection of mafic magma into a rhyolitic magma body is inferred to have triggered the earliest caldera-forming eruption at Newberry.

Templeton, J. H.

2010-12-01

382

Climate model calculations of the effects of volcanoes on global climate. Status report, 1 December 1991-30 November 1992  

SciTech Connect

An examination of the Northern Hemisphere winter surface temperature patterns after the 12 largest volcanic eruptions from 1883-1992 shows warming over Eurasia and North America and cooling over the Middle East which are significant at the 95 percent level. This pattern is found in the first winter after tropical eruptions, in the first or second winter after midlatitude eruptions, and in the second winter after high latitude eruptions. The effects are independent of the hemisphere of the volcanoes. An enhanced zonal wind driven by heating of the tropical stratosphere by the volcanic aerosols is responsible for the regions of warming, while the cooling is caused by blocking of incoming sunlight.

Robock, A.

1992-01-01

383

19. VIEW OF CRUDE ORE BINS FROM EAST. EAST CRUDE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

19. VIEW OF CRUDE ORE BINS FROM EAST. EAST CRUDE ORE BIN IN FOREGROUND WITH DISCHARGE TO GRIZZLY AT BOTTOM OF VIEW. CONCRETE RETAINING WALL TO LEFT (SOUTH) AND BOTTOM (EAST EDGE OF EAST BIN). - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

384

Volcano geodesy: The search for magma reservoirs and the formation of eruptive vents  

NASA Astrophysics Data System (ADS)

Routine geodetic measurements are made at only a few dozen of the world's 600 or so active volcanoes, even though these measurements have proven to be a reliable precursor of eruptions. The pattern and rate of surface displacement reveal the depth and rate of pressure increase within shallow magma reservoirs. This process has been demonstrated clearly at Kilauea and Mauna Loa, Hawaii; Long Valley caldera, California; Campi Flegrei caldera, Italy; Rabaul caldera, Papua New Guinea; and Aira caldera and nearby Sakurajima, Japan. Slower and lesser amounts of surface displacement at Yellowstone caldera, Wyoming, are attributed to changes in a hydrothermal system that overlies a crustal magma body. The vertical and horizontal dimensions of eruptive fissures, as well as the amount of widening, have been determined at Kilauea, Hawaii; Etna, Italy; Tolbachik, Kamchatka; Krafla, Iceland; and Asal-Ghoubbet, Djibouti, the last a segment of the East Africa Rift Zone. Continuously recording instruments, such as tiltmeters, extensometers, and dilatometers, have recorded horizontal and upward growth of eruptive fissures, which grew at rates of hundreds of meters per hour, at Kilauea; Izu-Oshima, Japan; Teishi Knoll seamount, Japan; and Piton de la Fournaise, Réunion Island. In addition, such instruments have recorded the hour or less of slight ground movement that preceded small explosive eruptions at Sakurajima and presumed sudden gas emissions at Galeras, Colombia. The use of satellite geodesy, in particular the Global Positioning System, offers the possibility of revealing changes in surface strain both local to a volcano and over a broad region that includes the volcano.

Dvorak, John J.; Dzurisin, Daniel

1997-08-01

385

Kilauea's Explosive Past: Understanding Violent Explosions at Hawai'i's most Active Volcano  

NASA Astrophysics Data System (ADS)

A sequence of explosions that occurred from Kilauea caldera around 1790 A.D. includes the most deadly pyroclastic eruptions recorded in the USA. The products, the upper part of the Keanak?ko`i tephra formation, are believed to be responsible for the deaths of a Hawaiian war party on the summit of the volcano. Little is known about the parent eruptions or even how many explosions there were in or around 1790; also, no hazard maps exist at Kilauea for this type of violent yet short-lived activity, with few clear precursors. The c. 1790 deposits show both marked sectoral changes and also, on a finer length scale, rapid lateral variability over distances of less than 1 kilometer. In the southern sector, they form a series of striking alternating coarse-grained beds, cross-bedded pyroclastic density current deposits (pdc) and accretionary-lapilli-bearing fine ashes. This study focuses primarily on the coarse-grained units, which are largely absent west and east of the caldera. Through characterization of the beds in the field and analysis of grain size and dispersal data, the size and intensity of these eruptions have been defined. The coarse-grained units include both pyroclastic fall and pdc deposits. Unusually, only bedding characteristics, (and not grain size or dispersal) unequivocally distinguish between these two transport processes. This study offers a clearer, more quantitative picture of the c. 1790 events and advances the understanding of how explosive eruptions can occur at an otherwise gently effusive volcano. It also constrains the dynamics associated with these events and improves volcanic hazard mitigation at Kilauea and shield volcanoes worldwide.

Weaver, S. J.; Houghton, B. F.; Swanson, D.

2010-12-01

386

Volcano geodesy: The search for magma reservoirs and the formation of eruptive vents  

USGS Publications Warehouse

Routine geodetic measurements are made at only a few dozen of the world's 600 or so active volcanoes, even though these measurements have proven to be a reliable precursor of eruptions. The pattern and rate of surface displacement reveal the depth and rate of pressure increase within shallow magma reservoirs. This process has been demonstrated clearly at Kilauea and Mauna Loa, Hawaii; Long Valley caldera, California; Campi Flegrei caldera, Italy; Rabaul caldera, Papua New Guinea; and Aira caldera and nearby Sakurajima, Japan. Slower and lesser amounts of surface displacement at Yellowstone caldera, Wyoming, are attributed to changes in a hydrothermal system that overlies a crustal magma body. The vertical and horizontal dimensions of eruptive fissures, as well as the amount of widening, have been determined at Kilauea, Hawaii; Etna, Italy; Tolbachik, Kamchatka; Krafla, Iceland; and Asal-Ghoubbet, Djibouti, the last a segment of the East Africa Rift Zone. Continuously recording instruments, such as tiltmeters, extensometers, and dilatometers, have recorded horizontal and upward growth of eruptive fissures, which grew at rates of hundreds of meters per hour, at Kilauea; Izu-Oshima, Japan; Teishi Knoll seamount, Japan; and Piton de la Fournaise, Re??union Island. In addition, such instruments have recorded the hour or less of slight ground movement that preceded small explosive eruptions at Sakurajima and presumed sudden gas emissions at Galeras, Colombia. The use of satellite geodesy, in particular the Global Positioning System, offers the possibility of revealing changes in surface strain both local to a volcano and over a broad region that includes the volcano.

Dvorak, J.J.; Dzurisin, D.

1997-01-01

387

EAST ARMENIAN READER.  

ERIC Educational Resources Information Center

THIS EAST ARMENIAN READER CONSISTS OF MATERIAL WRITTEN IN MESROPIAN SPELLING. AN INTRODUCTION (WRITTEN IN ENGLISH) PROVIDES A HISTORICAL REVIEW OF THE ARMENIAN LANGUAGE. GLOSSARIES (ARMENIAN-ENGLISH) AND RULES FOR ABBREVIATIONS, SPELLING, AND WORD COMPOSITION ARE INCLUDED. (GC)

ESSABAL, PAUL

388

Geochemistry of mud volcano fluids in the Taiwan accretionary prism  

E-print Network

Geochemistry of mud volcano fluids in the Taiwan accretionary prism Chen-Feng Youa, *, Joris. M prism. Overall, the Taiwanese mud volcano fluids are characterized by high Cl contents, up to 347 m the accretionary prisms. Recent Ocean Drilling Program (ODP) drill holes in the Barbados ridge complex, the Peru

Lin, Andrew Tien-Shun

389

Close-range acoustic scattering from mud volcanoes  

Microsoft Academic Search

Submarine mud volcanoes occur in many parts of the world's oceans and form an aperture for gas (mostly methane) and fluidized mud emission from the earth's interior. Their characteristics are of considerable interest to the geology, geophysics, geochemistry, and underwater acoustics communities. For the later community, mud volcanoes are important because they pose a potential source of clutter for active

Charles W. Holland; Thomas C. Weber; Giuseppe Etiope

2005-01-01

390

Volcanos and El Niño: signal separation in Northern Hemisphere winter  

Microsoft Academic Search

The frequent coincidence of volcanic forcing with El Niño events disables the clear assignment of climate anomalies to either volcanic or El Niño forcing. In order to select the signals, a set of four different perpetual January GCM experiments was performed (control, volcano case, El Niño case and combined volcano\\/El Niño case) and studied with advanced statistical methods for the

Ingo Kirchner; Hans-F. Graf

1995-01-01

391

Volcanos and El Nino: Signal separation in northern hemisphere winter  

Microsoft Academic Search

The frequent coincidence of volcanic forcing with El Nino events disables the clear assignment of climate anomalies to either volcanic or El Nino forcing. In order to select the signals, a set of four different perpetual January GCM experiments was performed (control, volcano case, El Nino case and combined volcano\\/El Nino case) and studied with advanced statistical methods for the

Ingo Kirchner; Hans-F. Graf

1995-01-01

392

Volcano Monitor: Autonomous Triggering of In-Situ Sensors  

NASA Technical Reports Server (NTRS)

In-situ sensors near volcanoes would be alerted by the Earth Observing-1 (EO-1) craft to take more frequent data readings. This project involves developing a sulfur-dioxide-sensing volcano monitor that will be able to transmit its readings through an Iridium modem.

Behar, Alberto; Davies, Ashley; Tran, Daniel Q.; Boudreau, Kate; Cecava, Johanna

2009-01-01

393

Eruptions of Hawaiian Volcanoes: Past, Present, and Future  

NSDL National Science Digital Library

The origin of the Hawaiian Islands, recorded eruptions, and eruption patterns are discussed in this United States Geological Survey (USGS) publication. The on-line book also covers volcano monitoring and research, landforms and structures, hazards and benefits, and a discussion of Loihi, Hawaii's newest volcano.

Robert Tilling

394

Subglacial, phonolitic volcanism at Hoodoo Mountain volcano, northern Canadian Cordillera  

Microsoft Academic Search

Hoodoo Mountain volcano (HMV) is a Quaternary phonolitic volcano situated on the north side of the Iskut River, in the Coast Mountains of northwestern British Columbia, Canada. Its activity spans the last 100,000 years, it may have erupted as recently as 9 ka, and it encompasses a volume of approximately 17 km3. Throughout its history, much of the volcanic activity

B. R. Edwards; J. K. Russell; R. G. Anderson

2002-01-01

395

Gas and aerosol emissions from Villarrica volcano, Chile  

Microsoft Academic Search

Here we report results from a multidisciplinary field campaign at Villarrica volcano, Chile, in March 2009. A range of direct sampling and remote sensing techniques was employed to assess gas and aerosol emissions from the volcano, and extend the time series of measurements that have been made during recent years. Airborne traverses beneath the plume with an ultraviolet spectrometer yielded

G. M. Sawyer; G. G. Salerno; J. S. Le Blond; R. S. Martin; L. Spampinato; T. J. Roberts; T. A. Mather; M. L. I. Witt; V. I. Tsanev; C. Oppenheimer

2011-01-01

396

Kilauea Volcano, Hawaii: A search for the volcanomagnetic effect  

USGS Publications Warehouse

Brief excursions of magnetic field differences between a base station and two satellite station magnetometers show only slight correlation with ground tilt at Kilauea Volcano. This result suggests that only transient, localized stresses occur during prolonged periods of deformation and that the volcano can support no large-scale pattern of shear stresses.

Davis, P.M.; Jackson, D.B.; Field, J.; Stacey, F.D.

1973-01-01

397

A warning bell? Tornillo events at Galeras Volcano, Colombia  

Microsoft Academic Search

In 1993, five of the six ash eruptions at Galeras Volcano, Colombia were preceded by distinctive seismic events, called tornillos. These unusual tremor wavelets have quasi-sinusoidal waveforms with screw-like envelope profiles and can last up to several minutes. Since December 1990, more than 60 of these events have been recorded at Galeras Volcano. As a class, they appear to be

M. Hellweg; D. Seidl

2003-01-01

398

Update of the volcanic risk map of Colima volcano, Mexico  

Microsoft Academic Search

The Colima volcano, located in western Mexico (19° 30.696 N, 103° 37.026 W) began its current eruptive process in February 10, 1999. This event was the basis for the development of two volcanic hazard maps: one for ballistics (rock fall) lahars, and another one for ash fall. During the period of 2003 to 2008 this volcano has had an intense

C. Suarez-Plascencia; F. J. Nuñez Cornu; B. Marquez-Azua

2010-01-01

399

Density Imaging of Volcanoes with Atmospheric Muons using GRPCs  

E-print Network

for realising a precise 3D density-map of the volcano. Obviously, this imposes also to define a robust, portable at a fixed location permits mapping out the average column density in the volcano once the topography explorations. Provided the topography of the target is known, the measurement of the attenuation of the muon

Paris-Sud XI, Université de

400

Geochemical stratigraphy and magmatic evolution at Arenal Volcano, Costa Rica  

E-print Network

Geochemical stratigraphy and magmatic evolution at Arenal Volcano, Costa Rica Louise L. Bolge a Miravalles (OSIVAM), Instituto Costarricense de, Electricidad (ICE), Apdo. 10032-1000, Costa Rica Received 13; tephrostratigraphy; Central American arc 1. Introduction Arenal is a small strato volcano located in Costa Rica (10

401

Using Google Earth to Study the Basic Characteristics of Volcanoes  

ERIC Educational Resources Information Center

Landforms, natural hazards, and the change in the Earth over time are common material in state and national standards. Volcanoes exemplify these standards and readily capture the interest and imagination of students. With a minimum of training, students can recognize erupted materials and types of volcanoes; in turn, students can relate these…

Schipper, Stacia; Mattox, Stephen

2010-01-01

402

Using Google Earth to Study the Basic Characteristics of Volcanoes  

NSDL National Science Digital Library

With the advent of Google Earth and the database of volcanoes supplied by the Smithsonian Institution's Global Volcanism Program, students can describe almost any volcano on Earth. In this article, the authors guide students to use tools in Google Earth t

Schipper, Stacia; Mattox, Stephen

2010-11-01

403

Chronology, chemistry, and origin of trachytes from Hualalai Volcano, Hawaii  

Microsoft Academic Search

Hualalai Volcano is unique among Hawaiian volcanoes in that it possesses a relatively high proportion of evolved, trachytic lavas that were erupted at the beginning of the alkalic, postshield phase of volcanism. These evolved lavas yield insights into magma sources, magma supply rates, and the evolution of the subvolcanic magmatic plumbing system at this time. Trachyte lavas are exposed at

Brian L. Cousens; David A. Clague; Warren D. Sharp

2003-01-01

404

ARTICLE IN PRESS Volcano geodesy and magma dynamics in Iceland  

E-print Network

ARTICLE IN PRESS Volcano geodesy and magma dynamics in Iceland Erik Sturkell a,*, Pa´ll Einarsson b; received in revised form 19 December 2004 Abstract Here we review the achievements of volcano geodesy and continuous Global Positioning System (GPS) geodesy, and interferometric analysis of synthetic aperture radar

Pedersen, Rikke

405

Gases of mud volcanoes in the Copper River Basin, Alaska  

Microsoft Academic Search

The gases emitted from mud volcanoes in the Copper River Basin of Alaska fall into two distinct types which are not mixed during vertical migration. The gases in the eastern volcanoes are nearly pure carbon dioxide, whereas the western ones contain methane and nitrogen and almost no carbon dioxide. Chemical and carbon isotopic compositions suggest the carbon dioxide rich gases

Robert H. Reitsema

1979-01-01

406

Petrologic diversity of Hrafnfjordur central volcano, northwest Iceland: Iceland's oldest central volcano  

NASA Astrophysics Data System (ADS)

Hrafnfjordur central volcano in northwest Iceland is exposed along the southern and western fjords of the Jokulfirdir, encompassing an area of ~400 km2. Field studies in 2004 and 2011 under the auspices of the Keck Geology Consortium investigated the southern and western portions of the Hrafnfjordur central volcano, mapping and sampling approximately 75% of the system. Hrafnfjordur central volcano has not been dated, but a basalt underlying tuff correlated to central volcano deposits yielded a whole-rock Ar/Ar plateau age of 14.20 +/- 0.33 (2?) Ma (Jordan & Duncan, unpub. data). The dated lava is ~550 m below the tuff, and applying an accumulation rate of 1,600 m/m.y. (Kristjansson & Jonsson, 2007) produces an estimated age of ~13.9 Ma. This would make Hrafnfjordur the oldest central volcano exposed in Iceland. Mapping and sampling to this point have documented abundant andesite and dacite lavas, and several sequences of basalts and basaltic andesites. A notable feature of Hrafnfjordur central volcano is the absence of true rhyolites in the area mapped so far. A suite of dacites exposed in the fjord Hrafnfjordur exhibits a tight linear trend of decreasing Zr (1010-460 ppm) with increasing SiO2 (65.3-69.9 wt.%), indicating progressive zircon-involved fractionation. Elevated Zr/Nb of the parental dacite, relative to local basalts, precludes an origin by fractional crystallization from a basaltic parent, and thus its origin is interpreted to be crustal melting. A dacite exposed at Leirufjordur falls on the same trend and may correlate with those at Hrafnfjordur. Another trend of dacites and andesites sampled in both fjords is characterized by low Zr (160-200 ppm). This trend could represent magma mixing between basalt and a hypothetical highly evolved low-Zr high-silica rhyolite that either is not exposed or was never erupted. Most of the andesites and basaltic andesites plot on inflected trends consistent with an origin primarily by fractional crystallization from a basaltic parent, but several plot in compositional "no man's land" indicating magma mixing. Reconnaissance of an isolated silicic exposure at the summit of Sauratindur, ~35 km southwest (near Isafjordur) and perhaps similar in age, revealed another dacite with distinct geochemical trends. Further studies will finish the mapping and sampling of Hrafnfjordur central volcano and dating of units within the system.

Jordan, B. T.

2012-12-01

407

The 2006 eruption of Augustine Volcano, Alaska  

USGS Publications Warehouse

Augustine Volcano, the most historically active volcano in Alaska's Cook Inlet region, again showed signs of life in April 2005. Escalating seismic unrest, ground deformation, and gas emissions culminated in an eruption from January 11 to mid-March of 2006, the fifth major eruption in 75 years. The eruption began with a series of 13 short-lived blasts over 20 days that sent pyroclastic flows; snow, rock, and ice avalanches; and lahars down the volcano's snow clad flanks; ash clouds drifted hundreds of kilometers downwind. Punctuated explosive activity gave way to effusion of lava and emplacement of thick block-and-ash flows on the volcano's north flank that continued through mid-February. In mid-March renewed extrusion resulted in the building of a new, higher summit lava dome and two blocky lava flows on the north and northeast flanks of the cone. The eruption resulted in ash fall on many south-central Alaskan communities and disrupted air traffic in the region. Au