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1

Intra-Volcano Compositional Variability and the Role of Oceanic Lithosphere in West Maui and East Molokai Volcanoes  

NASA Astrophysics Data System (ADS)

West Maui and East Molokai, two Hawaiian volcanoes with depleted, Kea-type isotopic compositions, show fine-scale, intra-volcano isotopic correlations in the shield-stage lavas that are distinct from inter-volcano correlations across the Hawaiian chain. Strong isotopic similarities exist in stratigraphic sections through the late shield stage of these two contemporaneous (1.5-2 Ma) Kea-type volcanoes. The depleted Hf, Pb, Sr and Nd isotope compositions of W. Maui and E. Molokai show limited variability and have a strong affinity to the Hawaiian Kea component. ?Hf ranges from +11.5 to +13.5 and +12.6 to +13.3 in W. Maui and E. Molokai, respectively; W. Maui shows an increase in ?Hf with depth. 206Pb/204Pb compositions are 18.34-18.54 and 18.42-18.59 for these same volcanoes. Hf and Pb isotope compositions do not correlate significantly. Even over a limited isotopic range, ?Nd compositions (W. Maui: +6.6 to +7.6; E. Molokai: +7.1 to +7.3) correlate inversely with 87Sr/86Sr (W. Maui: 0.70337-0.70363; E. Molokai: 0.70341-0.70362). 87Sr/86Sr and 206Pb/204Pb compositions in E. Molokai and deeper samples from W. Maui show a positive, linear correlation. This trend is orthogonal to the inter-volcano Hawaiian trend, and thus does not reflect mixing between components that typically dominate archipelago-scale sampling of magma sources in Hawaii. A positive Sr-Pb isotope correlation may reflect involvement of oceanic lithosphere, the geochemical signature of which is age-dependent. We have modeled the isotopic compositions of upper, hydrothermally altered basaltic segments and lower gabbroic segments of ancient (1.5-2 Ga) and younger (110 Ma) oceanic lithosphere. The fine-scale compositional trends we observe at W. Maui and E. Molokai are consistent with the interaction of plume-generated Kea-type magmas with the local, 110 Ma Pacific lithosphere. These compositional variations are observed only in specific sections of the stratigraphy, and so must result from processes that operate over time scales much shorter than the life of the volcano.

Gaffney, A. M.; Nelson, B. K.; Blichert-Toft, J.

2002-12-01

2

The distribution of geochemical heterogeneities in the source of Hawaiian shield lavas as revealed by a transect across the strike of the Loa and Kea spatial trends: East Molokai to West Molokai to Penguin Bank  

NASA Astrophysics Data System (ADS)

An important feature of <2 Ma Hawaiian volcanoes is that they define two sub-parallel spatial trends known as the Loa- and Kea-trends. On the Island of Hawaii, the <1.5 Ma shield lavas on the Loa and Kea spatial trends have distinctive geochemical characteristics that are designated as Loa-type and Kea-type. These geochemical differences are clearly expressed in Sr, Nd, Hf and Pb isotopic ratios, major element contents, and ratios of incompatible elements. They are interpreted to reflect varying proportions of sediment, basalt, gabbro and peridotite in subducted oceanic lithosphere. Pb isotopic ratios indicate that the Loa-type component reflects ancient subduction, >2.5 Ga, whereas the Kea-type component reflects younger subduction, <1.5 Ga. To evaluate the temporal persistence of these geochemical differences in the source of Hawaiian shield lavas, we analyzed lavas from the ˜1.5 to 2 Ma Molokai Island volcanoes, East and West Molokai, and the adjacent submarine Penguin Bank. The three volcanoes form a nearly east-west trend that crosscuts the Loa and Kea spatial trends at a high angle; consequently we can determine if these older lavas are Kea-type in the east and Loa-type in the west. All lavas collected from the subaerial flanks of East Molokai, a Kea-trend volcano, have Kea-type geochemical characteristics; however, dive samples collected from Wailau landslide blocks, probably samples of the East Molokai shield that are older than those exposed on the subaerial flanks, include basalt with Loa-type geochemical features. Shield lavas from West Molokai and Penguin Bank, both on the Loa-trend, are dominantly Loa-type, but samples with Kea-type compositions also erupted at these Loa-trend volcanoes. The Loa-trend volcanoes, Mahukona, West Molokai, Penguin Bank, and Koolau, have also erupted lavas with Kea-type geochemical characteristics, and the Kea-trend volcanoes, Mauna Kea, Kohala, Haleakala, and East Molokai, have erupted lavas with Loa-type geochemical characteristics. The presence of both Loa- and Kea-type lavas in a volcano provides constraints on the distribution of geochemical heterogeneities in the source of Hawaiian shield basalts. Two plausible models are: (1) source components with Loa- and Kea-type geochemical characteristics are present in the sources of all <2 Ma shields, but the Kea-to-Loa proportion is higher beneath Kea-trend than Loa-trend volcanoes, or (2) the magma source contains a uniform proportion of Loa- and Kea-type components, but these components have different solidi. Magmas derived from the low-temperature regions of the source preferentially sample the component with the lower solidus temperature and form Loa-type lavas. In contrast, magmas derived from the relatively high-temperature regions of the source sample both low and high solidus components in the source and form Kea-type lavas. This model is supported by the linear correlations between isotopic ratios and calculated temperatures of estimated primary magmas.

Xu, Guangping; Huang, Shichun; Frey, Frederick A.; Blichert-Toft, Janne; Abouchami, Wafa; Clague, David A.; Cousens, Brian; Moore, James G.; Beeson, Melvin H.

2014-05-01

3

Penguin Bank: A Loa-Trend Hawaiian Volcano  

NASA Astrophysics Data System (ADS)

Hawaiian volcanoes along the Hawaiian Ridge from Molokai Island in the northwest to the Big Island in the southeast, define two parallel trends of volcanoes known as the Loa and Kea spatial trends. In general, lavas erupted along these two trends have distinctive geochemical characteristics that have been used to define the spatial distribution of geochemical heterogeneities in the Hawaiian plume (e.g., Abouchami et al., 2005). These geochemical differences are well established for the volcanoes forming the Big Island. The longevity of the Loa- Kea geochemical differences can be assessed by studying East and West Molokai volcanoes and Penguin Bank which form a volcanic ridge perpendicular to the Loa and Kea spatial trends. Previously we showed that East Molokai volcano (~1.5 Ma) is exclusively Kea-like and that West Molokai volcano (~1.8 Ma) includes lavas that are both Loa- and Kea-like (Xu et al., 2005 and 2007).The submarine Penguin Bank (~2.2 Ma), probably an independent volcano constructed west of West Molokai volcano, should be dominantly Loa-like if the systematic Loa and Kea geochemical differences were present at ~2.2 Ma. We have studied 20 samples from Penguin Bank including both submarine and subaerially-erupted lavas recovered by dive and dredging. All lavas are tholeiitic basalt representing shield-stage lavas. Trace element ratios, such as Sr/Nb and Zr/Nb, and isotopic ratios of Sr and Nd clearly are Loa-like. On an ?Nd-?Hf plot, Penguin Bank lavas fall within the field defined by Mauna Loa lavas. Pb isotopic data lie near the Loa-Kea boundary line defined by Abouchami et al. (2005). In conclusion, we find that from NE to SW, i.e., perpendicular to the Loa and Kea spatial trend, there is a shift from Kea-like East Molokai lavas to Loa-like Penguin Bank lavas with the intermediate West Molokai volcano having lavas with both Loa- and Kea-like geochemical features. Therefore, the Loa and Kea geochemical dichotomy exhibited by Big Island volcanoes existed at ~2.2 Ma when the Molokai Island volcanoes formed and has persisted until the present. References: Abouchami et al., 2005 Nature, 434:851-856 Xu et al., 2005 G3, doi: 10.1029/2004GC000830 Xu et al., 2007 G3, doi: 10.1029/2006GC001554

Xu, G.; Blichert-Toft, J.; Clague, D. A.; Cousens, B.; Frey, F. A.; Moore, J. G.

2007-12-01

4

Chaotic deposition by a giant wave, Molokai, Hawaii  

USGS Publications Warehouse

A coral-basalt breccia-conglomerate is exposed >60m above present sea level and nearly 2km inland from the present shoreline on the southwest side of East Molokai Volcano. This deposits was apparently laid down by a giant wave that broke over an outer reef, similar to the present fringing reef, and advanced as a turbulent bore over the back-reef flat, picking up a slurry of carbonate-rich debris and depositing it on the slopes inland as the wave advanced. U-series dating of coral fragments indicates that the age of this deposit is 240-200 ka. This giant wave was most likley caused by one of the many large submarine landslides that have been identified on the lower slopes of the major Hawaiian Islands. -from Authors

Moore, J.G.; Bryan, W.B.; Ludwig, K. R.

1994-01-01

5

Geologic Map of Kalaupapa Peninsula, Moloka‘i, Hawai‘i, USA  

USGS Publications Warehouse

Kalaupapa Peninsula, along the northern coast of East Moloka‘i volcano, is a remarkably well-preserved example of rejuvenated-stage volcanism from a Hawaiian volcano. Mapping of lava flows, vents and other volcanic constructs reveals a diversity of landforms on this small monogenetic basaltic shield. The late-stage lava distributary system of this shield is dominated by a prominent lava channel and tube system emanating from the primary vent, Kauhak? crater. This system, along with several smaller examples, fed five prominent rootless vents downslope from Kauhak?. This map shows the subaerial part of this volcanic construct at 1:30,000 scale and encompasses an area of approximately 20.6 km2.

Okubo, Chris H.

2012-01-01

6

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

7

Lava Flow From Fissure Eruption on Kilauea Volcano's East Rift Zone  

USGS Multimedia Gallery

A new fissure eruption in September 2011 on the east flank of Pu‘u ‘?‘? on K?lauea Volcano's east rift zone reminds us of the need to be aware of our ever-changing volcanic environment on Hawai‘i Island. The fissure—the source of the lava flow—is sh...

8

Volcanoes!!  

NSDL National Science Digital Library

5th grade students will be able to explain what makes a volcano erupt. 5th grade students will be able to list the effects that volcanoes have on the environment and people. Read through the page to gather more knowledge about volcanoes. After reading this, you should be able to explain what makes a volcano erupt Volcano Facts View a model of a volcano erupting Visual Model of a volcano erupting Use the web tool to make your own volcano erupt. Adjust the gas level and size to make ...

Kailey Fucaloro

2009-09-15

9

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

10

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

11

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

12

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

13

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.

14

The 1962 Flank Eruption of Kilauea Volcano and Structure of the East Rift Zone  

Microsoft Academic Search

On December 7-9, 1962, a small flank eruption occurred on the upper part of the east rift zone of Kilauea volcano. The six eruptive fissures, which show a right-offset en echelon pattern, extend more than 2 miles from Aloi crater eastward to the west slope of Kane Nut o Hamo. The total volume of erupted lava was small (426,000 cubic

James G. Moore; Harold L. Krivoy

1964-01-01

15

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

SciTech Connect

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 lowercrust 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 fraction 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. The east central Oregon velocity structure is nearly identical to that of the northwestern Nevada Basin and Range and the Modoc Plateau of northeastern California, and variations in the deep crustal structure about Newberry Volcano are consistent with tectonism involving crustal underplating, melting, and extension.

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

1988-09-10

16

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

17

Volcanoes  

NSDL National Science Digital Library

Students investigate the processes that build volcanoes, the factors that influence different eruption types, and the threats volcanoes pose to their surrounding communities. They use what they have learned to identify physical features and eruption types of several actual volcanic episodes.

2005-12-17

18

Volcanoes!  

NSDL National Science Digital Library

This site presents a summary of current volcanic eruptions and images and videos of volcanoes on Earth. Discussions of the characteristics of volcanism on other worlds in our solar system are also presented and are accompanied by maps and imagery. Links to volcano observatories, parks, and monuments around the world are also included.

19

Volcanoes and ENSO in millennium simulations: global impacts and regional reconstructions in East Asia  

NASA Astrophysics Data System (ADS)

The impacts and cooperative effects of volcanic eruptions and ENSO (El Niño/Southern Oscillation) are analyzed in a millennium simulation for 800-2005 AD using the earth system model (ESM) ECHAM5/MPIOM/JSBACH subject to anthropogenic and natural forcings. The simulation comprises two ensembles, a first with weak (E1, five members) and a second with strong (E2, three members) variability total solar irradiance. In the analysis, the 21 most intense eruptions are selected in each ensemble member. Volcanoes with neutral ENSO states during two preceding winters cause a global cooling in the year after eruptions up to -2.5°C. The nonsignificant positive values in the tropical Pacific Ocean indicate an El Niño-like warming. In the winter after an eruption, warming is mainly found in the Arctic Ocean and the Bering Sea in E2 warming extends to Siberia and central Asia. The recovery times for the volcano-induced cooling (average for 31 eruptions) vary globally between 1 and 12 years. There is no significant increase of El Niño events after volcanic eruptions in both ensembles. The simulated temperature and the drought indices are compared with corresponding reconstructions in East Asia. Volcanoes cause a dramatic cooling in west China (-2°C) and a drought in East China during the year after the eruption. The reconstructions show similar cooling patterns with smaller magnitudes and confirm the dryness in East China. Without volcanoes, El Niño events reduce summer precipitation in the North, while South China becomes wetter; La Niña events cause opposite effects. El Niño events in the winters after eruptions compensate the cooling caused by volcanoes in most regions of China (consistent with reconstructions), while La Niña events intensify the cooling (up to -2.5°C). The simulated and reconstructed drought indices show tripole patterns which are altered by El Niño events. The simulated impact of the Tambora eruption in 1815, which caused the "year without summer" of 1816 in Europe and North America and led to coldness and famines in the Chinese province Yunnan, depends crucially on the ENSO state of the coupled model. A comparison with reconstructed El Niño events shows a moderate cool climate with wet (in the south) and extreme dry anomalies (in the north) persisting for several years.

Zhang, Dan; Blender, Richard; Fraedrich, Klaus

2013-02-01

20

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.

Scott Johnson

21

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

22

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

E-print Network

NAME: Molokai Fish Pond & Fringing Reef Restoration LOCATION: Kaunakakai, Island of Molokai (Maui fish ponds on the fringing reef of the Hawaiian island of Molokai. Mangroves were planted in 1902 conditions and threaten to take over the reef flats and fish ponds. EXPECTED BENEFITS: Fine sediment flushed

US Army Corps of Engineers

23

Volcanoes  

MedlinePLUS

... by authorities and evacuate immediately from the volcano area to avoid flying debris, hot gases, lateral blast and lava flow. Be aware of mudflows . The danger from a mudflow increases near stream channels and with ... and low-lying areas. Remember to help your neighbors who may require ...

24

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

25

Evolution and dynamics of magmatic processes below Gede volcano, East-Java, Indonesia  

NASA Astrophysics Data System (ADS)

Subduction-zone volcanism produces a large variety of compositions and eruption styles, but silica-rich explosive eruptions from arc volcanoes are those that pose the most direct threat for those living on and around the volcanoes. The little known Gede volcano (East-Java, Indonesia) is a composite arc-volcano showing evidences of recurrent silicic explosive eruptions and it is a hazard to its 1 million residences settled on its flank also to the two most populated neighboring metropolises: Jakarta and Bandung. Here we present the results of a detailed petrological and geochemical study of Gede's deposits to untangle its magmatic evolution, the key magma reservoir processes, and try to use this information to better anticipate possible future eruptions at Gede. After field-work and dating of the main deposits we identified 5 pyroclastic units ranging from basaltic andesite to dacite, and of eruption ages from about 1 ky to > 45 ky. Bulk-rock major and trace element compositions can be explained as a combination of fractional crystallization and magma mixing/mingling. Crystallization trends evolve with time from wet (amphibole present and plagioclase delayed) to 'dry' (olivine and two pyroxenes, and plagioclase). Petrological and geochemical evidence for within-trend mixing/mingling are common and involve high-Si basalt and dacite end-members. Core to rim electron microprobe and LA-ICP-MS trace element analysis of main phenocrysts (amphibole, plagioclase, ortho- and clinopyroxene) record the details of repetitive magma mixing and mingling events. Cores of amphibole, ortho- and clinopyroxene in the Holocene units have low Mg/Fe, high REEs and Eu-anomaly, and are rimmed Mg/Fe, low REEs and no Eu-anomaly zones. These minerals are thus recording the intrusions of mafic, water-richer and crystal-poor magma into an evolved and partly crystallized magma reservoir. Modeling the diffusive re-equilibration between the crystal cores and rims provides the time elapsed since the intrusion of the primitive magmas, interaction between end-member magmas, and eruption, and this is less than a few years. Our study shows that Gede volcano has evolved in the last 50 ky from a water-rich to a water-poor fractionation series. Many eruptions of both series are probably triggered by injection of mafic magma in evolved magma reservoirs. This suggest that if new unrest occurs below Gede the eruptions are likely to be explosive but the time between new intrusion and eruption would be long enough for proper response for mitigating its potential hazards.

Krimer, Daniel; Costa, Fidel

2014-05-01

26

Trace element and isotopic geochemistry of lavas from haleakala volcano, East Maui, Hawaii: Implications for the origin of Hawaiian Basalts  

Microsoft Academic Search

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,

Chu-Yung Chen; Frederick A. Frey

1985-01-01

27

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

28

Multi-disciplinary continuous monitoring of Kawah Ijen volcano, East Java, Indonesia  

NASA Astrophysics Data System (ADS)

Kawah Ijen volcano (East Java, Indonesia) has been equipped since June 2010 with 3 broadband seismometers, temporary and permanent short-period seismometers. While the volcano did not experience any magmatic eruption for more than a century, several types of unrests occurred during the last years. Apart from the seismometers, temperature and leveling divers have been immerged in the extremely acidic volcanic lake (pH~0) that can be considered as a calorimeter. Finally, a meteorological station has been installed to better assess the influence of strong rainy seasons to the different recordings. While finding instruments capable of resisting in such extreme conditions has been particularly challenging, the coupling of lake monitoring techniques with seismic data improves the understanding and monitoring of the volcanic-hydrothermal system. To detect small velocity changes, the approach developed by Brenguier et al. (2008) and Clarke et al. (2011) has been implemented to the continuous monitoring. First, the influence of several parameters detrimental to the recovering of the NCF will be discussed (i.e.: different types of seismometers and their azimuthal distribution, presence of volcanic tremor in different frequency bands). We will then present the results of this technique compared to other monitored parameters such as the polarization and spectral attributes of the wavefield, seismo volcanic events spectral analysis and lake temperature and levels. Finally, the benefits of monitoring Kawah Ijen magmatic/hydrothermal system with seismic waves will be discussed.

Caudron, C.; Lecocq, T.; Syahbana, D.; Camelbeeck, T.; Bernard, A. M.; Surono, S.

2012-12-01

29

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

30

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

31

Extreme peralkalinity in delhayelite- and andremeyerite-bearing nephelinite from Nyiragongo volcano, East African Rift  

NASA Astrophysics Data System (ADS)

Highly peralkaline leucite nephelinite from the active volcano Nyiragongo in the Virunga province of the East African Rift contains globules of iron- and volatile-rich, highly peralkaline silicate glass with (Na + K)/Al up to 18 which has formed as a late differentiate of less peralkaline precursors, probably by fractional crystallization at a shallow level in the volcanic system. A number of uncommon minerals coexist with this glass (kalsilite, kirschsteinite, chlorbartonite, götzenite, delhayelite, umbrianite, zirconian cuspidine, andremeyerite (BaFe2Si2O7), other Ba-Fe-Ti silicate minerals, and unnamed alkali-barium phosphate and Zr-Nb-Ti silicate minerals). These minerals are members of late magmatic assemblages that have survived sub-solidus recrystallization. Combeite occurs as a near-solidus mineral. Low-variance mineral assemblages in Nyiragongo nephelinite define a cooling trend from eruptive temperatures ? 980 °C to the solidus of extremely peralkaline residual liquids at ca. 600 °C, followed by sub-solidus recrystallization and metasomatism down to ca. 500 °C. Oxygen fugacity well below the QFM buffer (QFM-2 to -3) persisted throughout the magmatic crystallization stage, but increased to above QFM during the final stage of postmagmatic recrystallization. Highly alkaline, volatile-rich minerals such as delhayelite, götzenite and cuspidine were stabilized by a combination of high peralkalinity and elevated activity of chlorine and fluorine; these conditions persisted to sub-solidus temperatures.

Andersen, Tom; Elburg, Marlina A.; Erambert, Muriel

2014-10-01

32

Beach and reef-flat sediments along the south shore of Molokai, Hawaii  

USGS Publications Warehouse

As part of the U.S. Geological Survey's multi-disciplinary Coral Reef Project addressing the health and geological variability of coral reef systems, sediment components and their distribution along the fringing reef on the south shore of the Hawaiian island of Molokai are being examined. Particular interest is being paid to the types and origin of sediment found on the reef. The south shore of Molokai is sheltered by one of the largest fringing reefs in the US. At approximately 50 km in length, up to 1.5 km in width, and covered by 90% live coral in many locations, the reef seemingly should be able to provide ample sediment for large carbonate beaches. However, siliciclastic grains supplied by erosion of the basaltic uplands of Molokai are often the most conspicuous individual nearshore sediment type. Coralline algae and coral are the most common carbonate components of the beaches. On the nearshore reef-flat, chemically-altered carbonate grains, particularly coralline algae, are the most abundant component. Molluscs and Halimeda may be common in specific locations, but are usually minor components. Sediment calcium carbonate levels increase to the west from a minimum at Kamalo, and are high along the east shore of Molokai. However, these general island-scale trends may be overridden by local influences, such as protected stream mouths or high carbonate growth rates. Additionally, trends seen on the beach and nearshore environments may not reflect trends a few hundred meters offshore since shore normal trends are more pronounced than shore parallel ones.

Calhoun, R.S.; Field, M.E.

2000-01-01

33

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

34

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

35

Iceland: Grímsvötn Volcano  

Atmospheric Science Data Center

article title:  Grímsvötn Volcano Injects Ash into the Stratosphere     ... p.m. local time (1730 UTC) on Saturday, May 21, 2011. The volcano, located approximately 140 miles (220 kilometers) east of the capital ...

2013-04-17

36

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

37

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

38

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

39

An Academic Development Plan for the Island of Molokai in Hawaii, 1990-1996.  

ERIC Educational Resources Information Center

Since 1970, Maui Community College (MCC) has offered credit courses on the island of Molokai, with the program expanding considerably in 1986 with the inception of the MCC-Molokai Center. Developed to project a more stable and comprehensive program for the residents of Molokai, this academic development plan outlines the priorities of MCC on the…

Pezzoli, J. A.

40

Stress and mass changes during the 2011-2012 unrest at Kawah Ijen volcano, East Java, Indonesia  

NASA Astrophysics Data System (ADS)

Kawah Ijen volcano (East Java, Indonesia) has been equipped since June 2010 with 3 broadband seismometers, temporary and permanent short-period seismometers. While the volcano did not experience any magmatic eruption for more than a century, several types of unrests occurred during the last years. Apart from the seismometers, temperature and leveling divers have been immerged in the extremely acidic volcanic lake (pH ~ 0). While finding instruments capable of resisting in such extreme conditions has been particularly challenging, the coupling of lake monitoring techniques with seismic data improves the understanding and monitoring of the volcanic-hydrothermal system. To detect small velocity changes, the approach developed by Brenguier et al. (2008) and Clarke et al. (2011) has been implemented to monitor Ijen volcano. First, the influence of several parameters detrimental to the recovering of the cross correlation function will be discussed (i.e.: different types of seismometers and their azimuthal distribution, presence of volcanic tremor in different frequency bands). At Kawah Ijen, the frequency band that is less affected by the volcanic tremor and the seasonal fluctuations at the source ranges between 0.5-1.0 Hz. Moreover, a stack of 5 days for the current CCF gives reliable results with low errors and allows to detect fluctuations which are missed using a 10-day stack. We will then present the results of this technique compared to other seismic parameters (e.g.: seismo volcanic events spectral analysis) and temporal changes in lake temperature, color or lake levels that occurred during 2011-2012 crises that were the strongest ever recorded by the seismic monitoring network. An unrest commenced in October 2011 with heightened VT (Volcano Tectonic) earthquakes and low frequency events activity, which culminated mid-December 2011. This unrest was correlated with an enhanced heat and hydrothermal fluids discharge to the crater and significant variations of the relative velocities (-1%). This suggests an important build-up of stress into the system. VT earthquakes opened pathways for the fluids to ascend, by increasing the permeability of the system, which latter allowed the initiation of monochromatic tremor (MT) when the steam/gases interacted with the shallow portions of the aquifer. Our calculations evidence a higher contribution of steam in March 2012 that might explain the increase of the MT frequency when bubbles were observed at the lake surface. This period was also characterized by short-lived but strong velocity variations, related to water level rises containing important amount of bubbles, and important heat and mass discharges into the lake (2100 kJ/kg and 255 kg/s, respectively).

Caudron, C.; Lecocq, T.; Syahbana, D.; Camelbeeck, T.; Bernard, A. M.; Surono, S.

2013-12-01

41

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.

42

Magma Recharge and Mixing Processes That Triggered the Eruption of Trachytes and Phonolites at Suswa Volcano, Kenya Rift, East Africa  

NASA Astrophysics Data System (ADS)

Suswa Volcano, one of a series of Holocene central vent volcanoes located in the central part of the Kenya Rift, is divided into four major stages: 1) pre-caldera; 2) syn-caldera; 3) post-caldera I; and 4) post-caldera II. In addition to central vent volcanoes are basalt and basaltic-trachyandesite (BTA) flows (e.g. Tandamara and Elmenteita) that occur in low-lying areas adjacent to the central volcanoes. Both pre- and syn-caldera rocks include trachyte to phonolite. Syn-caldera rocks also include BTA similar to Tandamara. Matrix glass in pre-caldera samples is similar to whole-rock. However, for syn-caldera samples, light and dark mixed glasses are observed petrographically and compositions range from trachyandesite to trachyte. Pre-caldera samples have a phenocryst assemblage of anorthoclase (An0-5Ab50-60Or30-45), clinopyroxene (En27Fs28Wo45) and Fe-Ti oxide. Syn-caldera trachyte-phonolite contain this same assemblage but also plagioclase (An52Ab45Or3), with a composition identical to BTA samples. Clearly, the syn-caldera event represents magma mixing between BTA and trachyte. With the developing East Africa rifting, introduction of mafic magmas into the Suswa trachytic chamber was possible, similar to the rupture events in Ethiopia in 2005 (Wright et al., 2006). Post-caldera rocks have phenocrysts of alkali feldspar, olivine (Fa70), clinopyroxene and Fe-Ti oxides. Post-caldera II alkali feldspars are zoned and contain two different core compositions, one with low anorthite content similar to pre- and syn-caldera samples (An3Ab64Or33) and the other with higher anorthite content (An17Ab69Or14). They exhibit oscillatory zoning, with compositional variation between Ca2O and K2O and have thin rims with composition similar to the matrix feldspars. The thin rims may represent magma recharge that triggered eruption of the phonolite. Matrix glass in post-caldera rocks includes both trachyandesite and phonolite, indicating that hybridization of the contrasting magmas is still ongoing. Processes in addition to mixing contribute to this dynamic volcanic setting. Post-caldera rocks have compositions of essentially all elements that are intermediate between BTA and trachyte, as appropriate to mixing. However, samples show variable Na20 content at constant K20, Fe0, MgO, and CaO. A possible explanation for this variable Na2O content is assimilation of sodalite-bearing syenite roof and sidewall rocks into the evolving magma chamber. References: Wright, T.J., et al., 2006, Magma-maintained rift segmentation at continental rupture in the 2005 Afar dyking episode. Nature, 442: 291-294.

Espejel-Garcia, V.; Anthony, E. Y.; Ren, M.; MacDonald, R.; White, J. C.

2007-12-01

43

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

44

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

45

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

46

Magnetic Properties from the East Rift Zone of Kilauea: Implications for the Sources of Aeromagnetic Anomalies over Hawaiian Volcanoes  

NASA Astrophysics Data System (ADS)

Aeromagnetic studies of the Island of Hawai‘i provide insights into geologic structure. High-amplitude short-wavelength anomalies occur along the southwest and east rift zones (ERZ) of Kilauea, the youngest volcano on the island. These anomalies have been attributed to contrast between highly magnetic intrusions at depth and less magnetic altered rocks. Anomalies along rift zones of the older volcanoes on the island have lower amplitude or are lacking. To better understand the origin of the high-amplitude anomalies, magnetic properties were obtained for samples from existing 1.7 - 2.0 km deep bore holes located on the ERZ 30 - 40 km east of the summit of Kilauea but not over associated aeromagnetic maxima. The bore holes penetrate subaerial flows, submarine flows, and intrusions. Average values of total magnetization (MT) based on measurements of magnetic susceptibility (?) and NRM range from ~5.5 A/m for terrestrial flows to ~10 A/m for pillow basalts. MT of intrusions varys with depth. In shallow intrusions (< ~850 m depth), MT averages ~12 A/m, whereas in deep intrusions MT averages ~9 A/m. In contrast, to flows and shallow intrusions, deep intrusions have unstable NRMs that commonly diminish >80% during AF demagnetization at a peak field of 10 mT. The NRMs of deep intrusions were probably affected by drilling, and consequently their laboratory MT values may be much larger than in situ values. Therefore, the deep intrusions are more likely to have relatively low magnetizations rather than the high magnetizations that were used in previous aeromagnetic models.¶ The contrast in NRM stability for shallow and deep intrusions reflects differences in magnetic grain size. The average ARM/? for shallow intrusions is ~4 times that of deep intrusions. Also, deep intrusions have high Curie temperatures (TC>550 °C) whereas shallow intrusions commonly have low TC, averaging ~165 °C. The fine magnetic grain size and low TC of shallow intrusions are interpreted as the result of rapid crystallization after degassing. Limited oxygen in the subsurface environment would inhibit formation of ilmenite and thereby preserve high Ti-magnetite.¶ After heating in air to ~300 °C and above, TC and room-temperature saturation magnetization (MS) of shallow intrusions increase dramatically. On average, MS at ~25 °C of shallow intrusions increases by a factor of 2.4 after heating to 600 °C. Susceptibility increases similarly after heating in air but does not increase after heating in argon. In the presence of oxygen, Ti apparently separates even at moderate temperature, raising the TC and thereby MS and ?. If NRM increases in a similar manner (as is reasonable if the fine magnetic grain size is preserved), these rocks could attain MT in excess of 20 - 25 A/m. We speculate that this process occurs naturally in proximity to vents where repeated intrusions reheated (or maintained) these rocks to moderate temperatures. If such rocks are the source of anomalies along the Kilauea rift zones then destruction of the fine-grained titanomagnetite over time could explain the lack of prominent anomalies along older rift zones.

Rosenbaum, J. G.; Reynolds, R. L.; Trusdell, F.; Kauahikaua, J. P.

2009-12-01

47

Volcano Live  

NSDL National Science Digital Library

Volcano Live contains maps of volcanoes from around the world, a kids' page that provides volcano education links for teachers and students, a volcano glossary, volcano news, links to live video cams of volcanoes, geography and volcano information of countries around the world, and video clips of active volcanoes. There is also information for travelling to volcanoes, a volcano photo section, a section on the destruction of Pompeii, a volcanology section, and volcano safety rules.

John Seach

48

Full Vector Studies of the Last 10 Thousand Years Derived From The East Maui Volcano Hawaii  

NASA Astrophysics Data System (ADS)

We have determined the paleointensity of nine lavas flows that recorded the last 10 kyrs of geomagnetic field behavior from the youngest and largest of the two edifices of the island of Maui (i.e. Hana Volcanics, East Maui) with the multispecimen parallel differential pTRM method [Dekkers and Böhnel, EPSL, 248, 508-517, 2006]. The flows are characterized by irreversible Curie curves indicating two kinds of magnetic carriers: one almost pure magnetite and the second one Ti-rich magnetite with possible traces of titanomaghemite. The coercivity of remanence (Hcr) suggests that low-coercivity grains carry the NRM. Magnetic minerals from all of these flows are scattered within the PSD range with the exception of site HKAM (age 4.07±+0.09 ka) that lies in the SD range. The multispecimen method involves giving a laboratory pTRM to pristine specimens in different field strengths parallel to the original TRM; note that all pTRMs are given within the same range. From an existing sample collection for paleosecular variation studies [Herrero-Bervera and Valet, PEPI, 161, 267-280, 2007] we processed samples from 9 flows for paleointensity determinations ranging in age from 0.830.06 ka to 8.19±0.06 ka. pTRMs were given by in-field heating and cooling from 175 and to 260°C to avoid alteration. Low-field susceptibility variation appeared to be less than 10%, and sample sets from a few flows were heated to two different temperatures to check for consistency of results. All flows yielded good quality data. The paleointensity values increase to ~46 microTesla at ~ 2.2 ka and drop to ~22 microTesla at ~3.5 ka. At ~8.2 ka, ~39 microTesla is obtained, i.e. slightly higher than the present-day value (36 microTesla). Our paleointensity results (at least 7 flows) correlate well with the absolute paleointensity global determinations. The influence of a recently proposed domain-state correction [Fabian and Leonhardt, 2010, EPSL] on the paleointensity values will be investigated and shown.

Herrero-Bervera, E.; Dekkers, M. J.; Bohnel, H.; Hagstrum, J. T.; Champion, D. E.

2010-12-01

49

Paralysis at the Top of a Roaring Volcano: Israel and the Schooling of Palestinians in East Jerusalem  

ERIC Educational Resources Information Center

Conflicts over East Jerusalem are often thought to reflect larger conflicts in the Middle East. In this article, the authors focus on schooling in East Jerusalem in order to provide a better appreciation of the protracted conflict in the area. This close examination of schooling in East Jerusalem can illuminate reasons for the political paralysis…

Yair, Gad; Alayan, Samira

2009-01-01

50

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

51

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

52

77 FR 2019 - Security Zone; Passenger Vessel SAFARI EXPLORER Arrival/Departure, Kaunakakai Harbor, Molokai, HI  

Federal Register 2010, 2011, 2012, 2013, 2014

...USCG-2011-1159] RIN 1625-AA87 Security Zone; Passenger Vessel SAFARI EXPLORER Arrival/ Departure, Kaunakakai Harbor, Molokai, HI AGENCY: Coast Guard, DHS. ACTION: Temporary interim rule with request for...

2012-01-13

53

77 FR 24381 - Security Zone; Passenger Vessel SAFARI EXPLORER Arrival/Departure, Kaunakakai Harbor, Molokai, HI  

Federal Register 2010, 2011, 2012, 2013, 2014

...USCG-2011-1159] RIN 1625-AA87 Security Zone; Passenger Vessel SAFARI EXPLORER Arrival/ Departure, Kaunakakai Harbor, Molokai, HI AGENCY: Coast Guard, DHS. ACTION: Temporary interim rule; reopening of comment...

2012-04-24

54

Volcanoes Galore!  

NSDL National Science Digital Library

Here, you can check out videos and links to lots of nifty volcano stuff. Have fun! This is completely unrelated...but check it out anywho. sweet periodic table! Alaska Volcano Observatory Earthquakes and Volcanoes Check this one out for info on history\\'s most distructive volcano. Exploring Pompeii and Vesuvius Exploring the Environment: Volcanoes This will give you lots of background on how Volcanoes work, what the major parts are, and how they erupt. How Volcanoes Work A quick video on how to take a lava sample...hot! Lava Sampling on Kilauea Volcano, Hawai i A volcano in antartica? ...

Mr. Syracuse

2008-06-11

55

22. VIEW EAST TOWARDS WAIKOLU VALLEY OF PIPELINE ALONG PALI. ...  

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

22. VIEW EAST TOWARDS WAIKOLU VALLEY OF PIPELINE ALONG PALI. EYE BOLTS IN ROCK FACE AT RIGHT WERE USED BRIEFLY IN PLACE OF PIERS TO SUSPEND PIPE BY CHAIN BECAUSE THE CONCRETE PIERS WERE SUSCEPTIBLE TO HEAVY WAVE ACTION IN THIS AREA. - Kalaupapa Water Supply System, Waikolu Valley to Kalaupapa Settlement, Island of Molokai, Kalaupapa, Kalawao County, HI

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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

57

New K-Ar age determinations of Kilimanjaro volcano in the North Tanzanian diverging rift, East Africa.  

E-print Network

glaciations. The interacting between eruptive phenomena and the ice cover is assumed to have played slopes of Kilimanjaro. These belts are likely to occur above deep-seated fractures that have guided local stress field. Keywords: Kilimanjaro, East African Rift, K-Ar dating, volcanic history, Tanzania 2

Paris-Sud XI, Université de

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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

59

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.

60

The life cycle of an introduced caddisfly, Cheumatopsyche pettiti (Banks) (Trichoptera: Hydropsychidae) in Waikolu Stream, Molokai, Hawaii  

Microsoft Academic Search

Hawaiian streams contain some of the most unique species of aquaticinvertebrates known. In the 1960's a North American net spinningcaddisfly, Cheumatopsyche pettiti was inadvertentlyintroduced and is found in most perennial streams on Oahu, Maui,Molokai and Kauai. We investigated the life cycle of thistemperately evolved caddisfly in Waikolu Stream, Molokai. The lifecycle of C. pettiti was interpreted as probably multivoltinewith continuous

Boris C. Kondratieff; R. Jason Bishop; Anne M. Brasher

1997-01-01

61

Volcano Live  

NSDL National Science Digital Library

The volocanologist John Seach provides the latest volcano news and information on volcanoes all across the world. The website provides fun hands-on activities, tutorials in volcano safety and volcanology, and a glossary. Students can discover the geography of many areas of the world and how it impacts the likelihood of volcanic eruptions. Users can find links to numerous volcano cameras and maps. The amazing images of volcanoes from Seach's expeditions are a great addition to this informative site.

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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

63

Iceland Volcano  

Atmospheric Science Data Center

article title:  Eyjafjallajökull, Iceland, Volcano Ash Cloud     View larger ... Europe and captured this image of the Eyjafjallajökull Volcano ash cloud as it continued to drift over the continent. Unlike other ...

2013-04-23

64

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

Microsoft Academic Search

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

Gregory A. Piniak; Curt D. Storlazzi

2008-01-01

65

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

66

Wave and tidally-driven flowand sediment flux across a fringing coral reef: Southern Molokai, Hawaii  

Microsoft Academic Search

The fringing coral reef off the south coast of Molokai, Hawaii is currently being studied as part of a US Geological Survey (USGS) multi-disciplinary project that focuses on geologic and oceanographic processes that affect coral reef systems. For this investigation, four instrument packages were deployed across the fringing coral reef during the summer of 2001 to understand the processes governing

C. D. Storlazzi; A. S. Ogston; M. H. Bothner

67

Do the corals off Molokai,Hawaii preserve a long-term groundwater discharge record?  

NASA Astrophysics Data System (ADS)

Understanding long-term trends in coastal groundwater discharge on the island of Molokai, Hawaii, may provide important clues to better understand the nature of exchange across the land/sea interface and the impact of climate change. Human pressure also affects such exchange through changes in withdrawals rates. In response to increased urbanization, demand for coastal groundwater has also risen, as has the potential for coastal groundwater contamination. Coral cores were collected from several shallow sites along the south shore of Molokai and analyzed for a suite of trace elements, including select groundwater tracers. Long-term (1913-2002) stream discharge records from Molokai reveal a downward trend in base flow that imply a decrease in rainfall and coastal groundwater flow. In the Molokai corals, there was a statistically significant downward trend in monthly resolved yttrium and rare earth to calcium ratios over the last several decades. Thus the coral geochemical records appear to respond to changes in groundwater discharge associated with a decrease in base flow since 1913. These findings are further explored by testing naturally occurring radium isotopes as a groundwater tracer and oxygen isotopes as a freshwater tracer in the coral record.

Prouty, N. G.; Field, M.; Swarzenski, P.; Jupiter, S.

2008-12-01

68

Cascades Volcano Observatory - Learn About Volcanoes: Frequently Asked Volcano Questions  

NSDL National Science Digital Library

This page provides the answers to frequently asked questions about volcanoes. It is created by the United States Geological Survey. Topics addressed include: What Is A Volcano? Why Do Volcanoes Occur? How Do Volcanoes Erupt? Where Do Volcanoes Occur? When Will A Volcano Erupt? How Hot Is A Volcano? Can Lava Be Diverted? Do Volcanoes Affect Weather? What Types of Volcanoes are There? Which Eruptions Were The Deadliest? 20th Century Volcanic Eruptions and Their Impact. About 60 additional questions with answers are available under MORE FAQ's -Volcano Questions and Answers, and includes some sections on volcanoes of the western United States. Other links to volcano information are also available.

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Non-hotspot volcano chains produced by migration of shear-driven upwelling toward the East Pacific Rise  

NASA Astrophysics Data System (ADS)

While most oceanic volcanism is associated with the passive rise of hot mantle beneath the spreading axes of mid-ocean ridges (MOR), volcanism occurring off-axis reflects intraplate upper-mantle dynamics and composition, yet is poorly understood. Close to the East Pacific Rise (EPR), active magmatism propagated towards the spreading center to create a series of parallel volcanic ridges on the Pacific Plate (of length ~3500 km for the Pukapuka, and ~500 km for the Sojourn, and Hotu-Matua ridges). Propagation of this volcanism by ~20 cm/a, as well as asymmetry in a variety of geophysical observables across the EPR, indicates strong lateral eastward pressure-driven flow in the asthenosphere that is driven by upwelling beneath the South Pacific Superswell [1]. Although this pattern of large-scale mantle flow can account for the propagation of intraplate melting towards the EPR, it does not explain decompression melting itself. We hypothesize that shear-driven upwelling sustains off-axis volcanism. Shear-driven upwelling is a mechanism for mantle decompression that does not require lateral density heterogeneity to drive upwelling. For example, vertical flow emerges at the edges of viscosity anomalies, if the asthenosphere is sheared horizontally [2]. These two ingredients are present in the SE Pacific, where (1) shear across the asthenosphere is inferred to be greatest worldwide [2], and (2) lateral variability in mantle viscosity is indicated by geoid lineations and anomalies in seismic tomography [3]. Eastward pressure-driven flow from the South Pacific Superswell has been suggested to break up into fingers thus providing this variability in viscosity [3]. Our three-dimensional numerical models [4] show that asthenospheric shear can excite upwelling and decompression melting at the tip of low-viscosity fingers that are propelled by vigorous sublithospheric flow. This shear-driven upwelling is able to sustain intraplate volcanism that progresses towards the MOR, spreads laterally close to the axis, and weakly continues on the opposite plate. These predictions can explain the anomalously-fast eastward progression of volcanism, and its spatial distribution near the EPR. Moreover, for a heterogeneous mantle source involving a fertile component in addition to peridotite, the predicted systematics of volcanism can account for the geochemical trend observed along the Pukapuka ridge, and the enriched anomaly of EPR MOR-basalt at 16°S-20.5°S. Our study highlights the role of horizontal asthenospheric flow and mantle heterogeneity in producing linear chains of intraplate volcanism independent of a (deep-rooted) buoyancy source. [1] Conder, J. A., D. W. Forsyth, E. M. Parmentier (2002): J. Geophys. Res., 107(B12), 2344. [2] Conrad, C. P., T. A. Bianco, E. I. Smith, P. Wessel (2011): Nature Geoscience, 4, 317-321. [3] Harmon, N., D. W. Forsyth, D. S. Weeraratne, Y. Yang, S. C. Webb (2011): Earth Planet. Sci. Lett., 311, 306-315. [4] Ballmer, M. D., C. P. Conrad, E. I. Smith, N. Harmon (2013): Geology, in press.

Ballmer, Maxim D.; Conrad, Clinton P.; Harmon, Nicholas; Smith, Eugene I.

2013-04-01

70

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.

71

Erupting Volcanoes!  

NSDL National Science Digital Library

This lesson presents volcanoes through the making of volcano models. While students are constructing their physical representations of volcanoes, they will be filled with questions about volcanoes as well as how to build their models. This process will provide students with a tangible reference for learning about volcanoes and give them a chance to problem-solve as they build their models. Students will be able to observe how the eruption changes the original form of their volcano model. In this way, students see first hand how this type of phenomenon creates physical change. While students at this level may struggle to understand larger and more abstract geographical concepts, they will work directly with material that will help them build a foundation for understanding concepts of phenomena that sculpt the Earth.

72

Deadly Volcanos  

NSDL National Science Digital Library

This interactive slide show provides accounts of eight of history's most deadly volcanic eruptions. These eruptions are from both ancient and modern times, and include such volcanos as Mount Vesuvius, Tambora, Krakatau, Nevado del Ruiz, and Mount Pinatubo. Each slide features an illustration from the event, a written description with the name of the volcano, date, number of casualties, an account of the eruption, and a map showing the location of the volcano.

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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

74

Volcano Landslides  

NSDL National Science Digital Library

Information given in this United States Geological Survey (USGS) publication includes a description of volcano landslides, how they are generated, and their effects on surrounding areas. Case studies of specific volcano landslides are linked from this page, including Mt. St. Helens, Otake in Japan, Huila in Columbia, Mt. Rainier, and Casita in Nicaragua.

75

Chikurachki Volcano  

Atmospheric Science Data Center

... plume from the April 22, 2003, eruption of the Chikurachki volcano is portrayed in these views from the Multi-angle Imaging ... the volcanically active Kuril Island group, the Chikurachki volcano is an active stratovolcano on Russia's Paramushir Island (just south of ...

2013-04-16

76

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. ...

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Chemical, mineralogical, and isotopic characteristics of mud from the LUSI mud volcano, Sidoarjo, East Java, Indonesia: implications for the environment, public health, and eruption processes  

NASA Astrophysics Data System (ADS)

On May 29, 2006, mud and gases began erupting from a vent 150 meters away from a gas exploration well near Sidoarjo, East Java, Indonesia. The eruption, called the LUSI mud volcano, has continued 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 paper will present analytical results of mud samples collected in Sept. 2007 and Nov. 2008, and interpretive findings based on the analytical results. The 2007 mud sample contains high proportions of particles that could be ingestible by hand-mouth transmission (~98 vol % <250 microns,), inhalable into the upper respiratory tract (~80 vol % <10 microns), and respirable into the lung alveoli (~ 40 vol % <2.5 microns), so the mud and dust from the dried mud could be readily taken up by exposed individuals. Our results confirm those of a previous study that the levels of potentially toxic heavy metals or metalloids in the mud are low. A complex mixture of organic compounds in the mud is likely derived from petroleum source rocks. Although the 2007 mud sample contains several percent iron sulfides, net acid production tests indicate that enough carbonate material is also present to prevent the mud from becoming acid-generating due to weathering and sulfide oxidation in the near-surface environment. Water derived from settling mud deposits may have the potential to adversely affect the quality of surface- or groundwater sources for drinking water, due to high levels of fluoride, nitrate, iron, manganese, aluminum, sulfate, chloride, and total dissolved solids. The very high nitrate levels in the waters contained within the mud may present a source of nutrients that could enhance algal blooms and resulting adverse impacts such as hypoxia in fresh-water and marine ecosystems into which some of the mud is being discharged. In agreement with previous studies, water separated from the 2007 mud sample is compositionally and isotopically compatible with an origin as sedimentary formation water. The iron disulfide fraction of the mud sample is isotopically light, and likely formed by bacterial sulfate reduction during diagenesis of clay-rich rocks from which the mud was derived. A smaller, isotopically heavy monosulfide fraction likely formed later by thermogenic reduction of formation-water sulfate to sulfide and reaction of the resulting sulfide with reactive iron in the mud. Additional linked earth science and public health studies are needed to more fully understand eruption processes, and the potential environmental and health consequences of the erupting mud, waters, and gases, and of the accumulating mud deposits.

Plumlee, G. S.; Casadevall, T. J.; Wibowo, H. T.; Rosenbauer, R. J.; Johnson, C. A.; Breit, G. N.; Hageman, P. L.; Wolf, R. E.; Morman, S. A.

2009-12-01

78

Volcano spacing and plate rigidity  

SciTech Connect

In-plane stresses, which accompany the flexural deformation of the lithosphere under the load adjacent volcanoes, may govern the spacing of volcanoes in hotspot provinces. Specifically, compressive stresses in the vicinity of a volcano prevent new upwelling in this area, forcing a new volcano to develop at a minimum distance that is equal to the distance in which the radial stresses change from compressional to tensile (the inflection point). If a volcano is modeled as a point load on a thin elastic plate, then the distance to the inflection point is proportional to the thickness of the plate to the power of 3/4. Compilation of volcano spacing in seven volcanic groups in East Africa and seven volcanic groups of oceanic hotspots shows significant correlation with the elastic thickness of the plate and matches the calculated distance to the inflection point. In contrast, volcano spacing in island arcs and over subduction zones is fairly uniform and is much larger than predicted by the distance to the inflection point, reflecting differences in the geometry of the source and the upwelling areas.

Brink, U. (Stanford Univ., California (USA))

1991-04-01

79

Geology of Kilauea volcano  

SciTech Connect

This paper summarizes studies of the structure, stratigraphy, petrology, drill holes, eruption frequency, and volcanic and seismic hazards of Kilauea volcano. All the volcano is discussed, but the focus is on its lower east rift zone (LERZ) because active exploration for geothermal energy is concentrated in that area. Kilauea probably has several separate hydrothermal-convection systems that develop in response to the dynamic behavior of the volcano and the influx of abundant meteoric water. Important features of some of these hydrothermal-convection systems are known through studies of surface geology and drill holes. Observations of eruptions during the past two centuries, detailed geologic mapping, radiocarbon dating, and paleomagnetic secular-variation studies indicate that Kilauea has erupted frequently from its summit and two radial rift zones during Quaternary time. Petrologic studies have established that Kilauea erupts only tholeiitic basalt. Extensive ash deposits at Kilauea's summit and on its LERZ record locally violent, but temporary, disruptions of local hydrothermal-convection systems during the interaction of water or steam with magma. Recent drill holes on the LERZ provide data on the temperatures of the hydrothermal-convection systems, intensity of dike intrusion, porosity and permeability, and an increasing amount of hydrothermal alteration with depth. The prehistoric and historic record of volcanic and seismic activity indicates that magma will continue to be supplied to deep and shallow reservoirs beneath Kilauea's summit and rift zones and that the volcano will be affected by eruptions and earthquakes for many thousands of years. 71 refs., 2 figs.

Moore, R.B. (Geological Survey, Denver, CO (United States). Federal Center); Trusdell, F.A. (Geological Survey, Hawaii National Park, HI (United States). Hawaiian Volcano Observatory)

1993-08-01

80

Model Volcanoes  

NSDL National Science Digital Library

In this lesson, students will explore volcanoes by constructing models and reflect upon their learning through drawing sketches of their models. Once they have finished making their models, they will experiment with making their volcanoes erupt. They will observe how eruption changes the original form of their volcano models. In this way, students see first hand how this type of phenomena creates physical change. While students at this level may struggle to understand larger and more abstract geographical concepts, they will work directly with material that will help them build a foundation for understanding concepts of phenomena that sculpt the earth.

81

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

82

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....

83

Volcano Preparedness  

MedlinePLUS

... your local emergency officials. Mudflows Mudflows are powerful “rivers” of mud that can move 20 to 40 ... cannot see the volcano during an eruption. Avoid river valleys and low lying areas. Trying to watch ...

84

Volcano Hazards Program Webcams  

MedlinePLUS

Volcano Hazards Program Webcams Below is a list of webcams of U.S. volcanoes. All webcams are operated ... the webcam. Pu`u `O`o vent, Kilauea Volcano (HVO) Halema`uma`u from HVO, Kilauea Volcano ( ...

85

Surface deformation analysis of the Mauna Loa and Kilauea volcanoes, Hawaii , revealed by InSAR measurements  

Microsoft Academic Search

The Big Island of Hawaii is home to three volcanoes that have historically erupted. Hualalai, on the east side of the island, Mauna Loa, the largest volcano on the planet which has erupted 39 times since 1832 (most recently in 1984) and Kilauea, which has been in a state of continuous eruption since 1983 from vents on the volcano's east

F. Casu; M. Poland; G. Solaro; P. Tizzani; A. Miklius; E. Sansosti; R. Lanari

2009-01-01

86

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.

American Association for the Advancement of Science

2009-01-01

87

Volcano Hazards Program  

USGS Publications Warehouse

Diagram of common volcano hazards. The U.S. Geological Survey Volcano Hazards Program (VHP) monitors unrest and eruptions at U.S. volcanoes, assesses potential hazards, responds to volcanic crises, and conducts research on how volcanoes work. When conditions change at a monitored volcano, the VHP issues public advisories and warnings to alert emergency-management authorities and the public. See http://volcanoes.usgs.gov/ to learn more about volcanoes and find out what's happening now.

Venezky, Dina Y.; Myers, Bobbie; Driedger, Carolyn

2008-01-01

88

Volcano Seismology  

Microsoft Academic Search

-- A fundamental goal of volcano seismology is to understand active magmatic systems, to characterize the configuration of such systems, and to determine the extent and evolution of source regions of magmatic energy. Such understanding is critical to our assessment of eruptive behavior and its hazardous impacts. With the emergence of portable broadband seismic instrumentation, availability of digital networks with

BERNARD CHOUET

2003-01-01

89

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

90

Michigan Tech Volcanoes  

NSDL National Science Digital Library

The Michigan Tech Volcanoes Page encourages collaborative, interdisciplinary work on active volcanos, and links to resources for the Santa Maria Decade Volcano in Guatemala and for Central America's most frequently active volcano, Fuego. Also includes images of Pinatubo Volcano [one nice one taken from the Space Shuttle Endeavor] and some movies of laharic activity.

91

Cascades Volcano Observatory  

NSDL National Science Digital Library

The Cascades Volcano Observatory of the U.S. Geological Survey has announced a WWW server offering information on volcanically-induced geologic and hydrologic hazards as well as images of volcanoes and volcanic phenomena. Includes links to ther components of the USGS Volcano Hazards Program such as the Alaska and Hawaii Volcano Observatory and the international Volcano Disaster Assistance Program.

92

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

93

Volcanic hazards at Atitlan volcano, Guatemala  

USGS Publications Warehouse

Atitlan Volcano is in the Guatemalan Highlands, along a west-northwest trending chain of volcanoes parallel to the mid-American trench. The volcano perches on the southern rim of the Atitlan caldera, which contains Lake Atitlan. Since the major caldera-forming eruption 85 thousand years ago (ka), three stratovolcanoes--San Pedro, Toliman, and Atitlan--have formed in and around the caldera. Atitlan is the youngest and most active of the three volcanoes. Atitlan Volcano is a composite volcano, with a steep-sided, symmetrical cone comprising alternating layers of lava flows, volcanic ash, cinders, blocks, and bombs. Eruptions of Atitlan began more than 10 ka [1] and, since the arrival of the Spanish in the mid-1400's, eruptions have occurred in six eruptive clusters (1469, 1505, 1579, 1663, 1717, 1826-1856). Owing to its distance from population centers and the limited written record from 200 to 500 years ago, only an incomplete sample of the volcano's behavior is documented prior to the 1800's. The geologic record provides a more complete sample of the volcano's behavior since the 19th century. Geologic and historical data suggest that the intensity and pattern of activity at Atitlan Volcano is similar to that of Fuego Volcano, 44 km to the east, where active eruptions have been observed throughout the historical period. Because of Atitlan's moderately explosive nature and frequency of eruptions, there is a need for local and regional hazard planning and mitigation efforts. Tourism has flourished in the area; economic pressure has pushed agricultural activity higher up the slopes of Atitlan and closer to the source of possible future volcanic activity. This report summarizes the hazards posed by Atitlan Volcano in the event of renewed activity but does not imply that an eruption is imminent. However, the recognition of potential activity will facilitate hazard and emergency preparedness.

Haapala, J.M.; Escobar Wolf, R.; Vallance, James W.; Rose, W.I.; Griswold, J.P.; Schilling, S.P.; Ewert, J.W.; Mota, M.

2006-01-01

94

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 R.

2008-01-01

95

Santorini Volcano  

USGS Publications Warehouse

Santorini is one of the most spectacular caldera volcanoes in the world. It has been the focus of significant scientific and scholastic interest because of the great Bronze Age explosive eruption that buried the Minoan town of Akrotiri. Santorini is still active. It has been dormant since 1950, but there have been several substantial historic eruptions. Because of this potential risk to life, both for the indigenous population and for the large number of tourists who visit it, Santorini has been designated one of five European Laboratory Volcanoes by the European Commission. Santorini has long fascinated geologists, with some important early work on volcanoes being conducted there. Since 1980, research groups at Cambridge University, and later at the University of Bristol and Blaise Pascal University in Clermont-Ferrand, have collected a large amount of data on the stratigraphy, geochemistry, geochronology and petrology of the volcanics. The volcanic field has been remapped at a scale of 1:10 000. A remarkable picture of cyclic volcanic activity and magmatic evolution has emerged from this work. Much of this work has remained unpublished until now. This Memoir synthesizes for the first time all the data from the Cambridge/Bristol/Clermont groups, and integrates published data from other research groups. It provides the latest interpretation of the tectonic and magmatic evolution of Santorini. It is accompanied by the new 1:10 000 full-colour geological map of the island.

Druitt, T.H.; Edwards, L.; Mellors, R.M.; Pyle, D.M.; Sparks, R.S.J.; Lanphere, M.; Davies, M.; Barreirio, B.

1999-01-01

96

Iceland: Eyjafjallajökull Volcano  

Atmospheric Science Data Center

article title:  Eyjafjallajökull Volcano Ash Plume Particle Properties     ... satellite flew over Iceland's erupting Eyjafjallajökull volcano on April 19, 2010, its Multi-angle Imaging SpectroRadiometer (MISR) ...

2013-04-17

97

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

98

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

99

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

100

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.

David Tenenbaum

1997-01-02

101

Hawaiian Volcano Observatory  

NSDL National Science Digital Library

As part of the US Geological Survey, the Hawaiian Volcano Observatory (HVO) is charged with monitoring and researching volcanoes in Hawaii. The site provides current activity reports, hazard information, and a history of the two main volcanoes, Kilauea and Mauna Loa. In addition, the site provides information on three other volcanoes that are either active or potentially active. Visitors can also learn about earthquakes in Hawaii and the particular hazards posed by volcanos. Captivating photos help bring the volcanoes to life. Visitors can patronize the Photo Gallery for additional volcano photos. Cross links to additional information and sites are provided on every page.

102

Pressurized magma reservoir within the east rift zone of K?lauea Volcano, Hawai`i: Evidence for relaxed stress changes from the 1975 Kalapana earthquake  

NASA Astrophysics Data System (ADS)

We use 2000-2012 InSAR data from multiple satellites to investigate magma storage in K?lauea's east rift zone (ERZ). The study period includes a surge in magma supply rate and intrusion-eruptions in 2007 and 2011. The Kupaianaha area inflated by ~5 cm prior to the 2007 intrusion and the N?pau Crater area by ~10 cm following the 2011 intrusion. For the N?pau Crater area, elastic modeling suggests an inflation source at 5 ± 2 km depth or more below sea level. The reservoir is located in the deeper section of the rift zone for which secular magma intrusion was inferred for the period following the 1975 Mw7.7 décollement earthquake. Reservoir pressurization suggests that in this section of the ERZ, extensional stress changes due to the earthquake have largely been compensated for and that this section is approaching its pre-1975 state. Reservoir pressurization also puts the molten core model into question for this section of K?lauea's rift zone.

Baker, Scott; Amelung, Falk

2015-03-01

103

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

104

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

105

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

106

The Electronic Volcano  

NSDL National Science Digital Library

The Electronic Volcano offers links to many types of information on active volcanoes, such as maps, photographs, full texts of dissertations and a few elusive documents. The Electronic Volcano will guide you to resources in libraries or resources on other information servers including catalogs of active volcanoes, datasets for literature citations, electronic and hard-copy journals, visual information, maps, observatories and institutions, and a volcano name and country index.

107

Earth Layers and Volcanoes  

NSDL National Science Digital Library

Why do we have volcanoes? Use the information on the websites to answer the questions on the worksheet. Worksheet First, review the layers of the earth. Labeling the layers game Next, go through the maze and read the information given. Magic School Bus volcano game Now, study the different shapes of volcanoes. Click enter, then volcano types in the menu. Read about the 3 types of volcanoes. Discovery Kids Games Finally, watch ...

brookeshallow

2011-04-13

108

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.

109

Santorini Volcano  

NASA Astrophysics Data System (ADS)

What is it about Santorini (Thera) that attracts volcanologists? This small archipelago in the Aegean has captivated volcanic pilgrims since Fouque published his geologic study of the volcanic field in 1879 [Fouqué, 1879].It must be the combination of its spectacular setting, rising out of the blue waters of the Aegean, the remarkable exposures that lay open its violent past for everyone to see, or possibly the slower pace of life and remarkable Greek hospitality Perhaps it is the Lower Bronze Age town of Akrotiri, destroyed yet preserved by a large explosive eruption 3600 years ago. There are thousands of volcanoes yet to be studied on our planet, but for 140 years, groups of volcanologists have regularly visited this flooded caldera complex to add yet another bit of information to the foundation laid by Fouqué.

Heiken, Grant

110

Olivine-liquid relations of lava erupted by Kilauea volcano from 1994 to 1998: Implications for shallow magmatic processes associated with the ongoing east-rift-zone eruption  

USGS Publications Warehouse

From 1994 through 1998, the eruption of Ki??lauea, in Hawai'i, was dominated by steady-state effusion at Pu'u 'O??'??o that was briefly disrupted by an eruption 4 km uprift at Np??au Crater on January 30, 1997. In this paper, I describe the systematic relations of whole-rock, glass, olivine, and olivine-inclusion compositions of lava samples collected throughout this interval. This suite comprises vent samples and tube-contained flows collected at variable distances from the vent. The glass composition of tube lava varies systematically with distance and allows for the "vent-correction" of glass thermometry and olivine-liquid KD as a function of tube-transport distance. Combined olivine-liquid data for vent samples and "vent-corrected" lava-tube samples are used to document pre-eruptive magmatic conditions. KD values determined for matrix glasses and forsterite cores define three types of olivine phenocrysts: type A (in equilibrium with host glass), type B (Mg-rich relative to host glass) and type C (Mg-poor relative to host glass). All three types of olivine have a cognate association with melts that are present within the shallow magmatic plumbing system during this interval. During steady-state eruptive activity, the compositions of whole-rock, glass and most olivine phenocrysts (type A) all vary sympathetically over time and as influenced by changes of magmatic pressure within the summit-rift-zone plumbing system. Type-A olivine is interpreted as having grown during passage from the summit magmachamber along the east-rift-zone conduit. Type-B olivine (high Fo) is consistent with equilibrium crystallization from bulk-rock compositions and is likely to have grown within the summit magma-chamber. Lower-temperature, fractionated lava was erupted during non-steady state activity of the Na??pau Crater eruption. Type-A and type-B olivine-liquid relations indicate that this lava is a mixture of rift-stored and summit-derived magmas. Post-Na??pau lava (at Pu'u 'O?? 'o) gradually increases in temperature and MgO content, and contains type-C olivine with complex zoning, indicating magma hybridization associated with the flushing of rift-stored components through the eruption conduit.

Thornber, C.R.

2001-01-01

111

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

112

Gravity model studies of Newberry Volcano, Oregon  

SciTech Connect

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.

Gettings, M.E.; Griscom, A.

1988-09-10

113

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.

114

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

USGS Publications Warehouse

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, G.A.; Storlazzi, C.D.

2008-01-01

115

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....

116

Iceland: Eyjafjallajökull Volcano  

Atmospheric Science Data Center

article title:  Ash from Eyjafjallajökull Volcano, Iceland Stretches over the North Atlantic   ... that occurred in late March 2010, the Eyjafjallajökull Volcano in Iceland began erupting again on April 14, 2010. The resulting ash ...

2013-04-17

117

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.

118

The Volcano Adventure Guide  

Microsoft Academic Search

This guide contains vital information for anyone wishing to visit, explore, and photograph active volcanoes safely and enjoyably. Following an introduction that discusses eruption styles of different types of volcanoes and how to prepare for an exploratory trip that avoids volcanic dangers, the book presents guidelines to visiting 42 different volcanoes around the world. It is filled with practical information

Rosaly Lopes

2005-01-01

119

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.

Victor Camp

2001-10-01

120

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....

121

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

122

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

123

Aerosol Lesson: Volcano Types  

NSDL National Science Digital Library

This activity has students research a list of volcanoes and then write detailed information they researched under a column that identifies that type of volcano - Cinder Cone, Composite, or Shield. Included are a worksheet and a collection of links to referential websites about specific volcanoes.

124

Focus: alien volcanos  

Microsoft Academic Search

Part 1: Volcanoes on Earth - blowing their top; Part 2: Volcanoes of the inner Solar System - dead or alive: the Moon, Mercury, Mars, Venus; Part 3: Volcanoes of the outer Solar System - fire and ice: Io, Europa, Ganymede and Miranda, Titan, Triton, Enceladus.

Michael Carroll; Rosaly Lopes

2007-01-01

125

Focus: alien volcanos  

NASA Astrophysics Data System (ADS)

Part 1: Volcanoes on Earth - blowing their top; Part 2: Volcanoes of the inner Solar System - dead or alive: the Moon, Mercury, Mars, Venus; Part 3: Volcanoes of the outer Solar System - fire and ice: Io, Europa, Ganymede and Miranda, Titan, Triton, Enceladus.

Carroll, Michael; Lopes, Rosaly

2007-03-01

126

The hydrogeology of Kilauea volcano  

SciTech Connect

The hydrogeology of Kilauea volcano and adjacent areas has been studied since the turn of this century. However, most studies to date have focused on the relatively shallow, low-salinity parts of the ground-water system, and the deeper hydrothermal system remains poorly understood. The rift zones of adjacent Mauna Loa volcano bound the regional ground-water flow system that includes Kilauea, and the area bounded by the rift zones of Kilauea and the ocean may comprise a partly isolated subsystem. Rates of ground-water recharge vary greatly over the area, and discharge is difficult to measure, because streams are ephemeral and most ground-water discharges diffusely at or below sea level. Hydrothermal systems exist at depth in Kilauea's east and southwest rift zone, as evidenced by thermal springs at the coast and wells in the lower east-rift zone. Available data suggest that dike-impounded, heated ground water occurs at relatively high elevations in the upper east- and southwest-rift zones of Kilauea, and that permeability at depth in the rift zones. Available data suggest that dike-impounded, heated ground water occurs at relatively high elevations in the upper east- and southwest-rift zones of Kilauea, and that permeability at depth in the rift zones (probably [le]10[sup [minus]15] m[sup 2]) is much lower than that of unaltered basalt flows closer to the surface ([ge]10[sup [minus]10] m[sup 2]). Substantial variations in permeability and the presence of magmatic heat sources influence that structure of the fresh water-salt water interface, so the Ghyben-Herzberg model will often fail to predict its position. Numerical modeling studies have considered only subsets of the hydrothermal system, because no existing computer code solves the coupled fluid-flow, heat- and solute-transport problem over the temperature and salinity range encountered at Kilauea. 73 refs., 7 figs., 2 tabs.

Ingebritsen, S.E.; Scholl, M.A. (Geological Survey, Menlo Park, CA (United States))

1993-08-01

127

Cascades Volcano Observatory  

USGS Publications Warehouse

Washington's Mount St. Helens volcano reawakens explosively on October 1, 2004, after 18 years of quiescence. Scientists at the U.S. Geological Survey's Cascades Volcano Observatory (CVO) study and observe Mount St. Helens and other volcanoes of the Cascade Range in Washington, Oregon, and northern California that hold potential for future eruptions. CVO is one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and public safety. Learn more about Mount St. Helens and CVO at http://vulcan.wr.usgs.gov/.

Venezky, Dina Y.; Driedger, Carolyn; Pallister, John

2008-01-01

128

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

129

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

130

Glaciation of Haleakala volcano, Hawaii  

SciTech Connect

Early debates regarding the large (5 [times] 10 km) summit crater'' of Haleakala volcano (3,055 m altitude) on the island of Maui attributed its origin to renting, rifting, caldera collapse, or erosion. It now is commonly assumed to have resulted from headward expansion of giant canyons by stream erosion (Stearns, 1942). Slope maps and shaded relief images based on new USGS digital elevation data point to the apparent overfit of the canyons that drain the summit depression. Studies of drowned coral reefs and terraces on the offshore east rift of Haleakala indicate that this part of the volcano has undergone submergence of about 2 km, as well as tilting, since 850 ka ago. Such subsidence indicates that the summit altitude at the end of the shield-building phase reached ca. 5,000 m, well above both the present and full-glacial snowlines. A comparison with the radiometrically dated glacial record of Mauna Kea and its reconstructed snowline history suggests that Haleakala experienced 10 or more glaciations, the most extensive during marine isotope stages 20, 18, and 16. By isotope stage 10, the summit had subsided below the full-glacial snowline. Diamictons on the south slope of the volcano, previously described as mudflows, contain lava clasts with superchilled margins, identical to margins of subglacially erupted lavas on Mauna Kea. Glacier ice that mantled the upper slopes of the volcano continuously for several hundred thousand years and intermittently thereafter, is inferred to have carved Haleakala crater and the upper reaches of large canyons radiating from it.

Moore, J.G.; Mark, R. (Geological Survey, Menlo Park, CA (United States)); Porter, S.C. (Univ. of Washington, Seattle, WA (United States). Quaternary Research Center)

1993-04-01

131

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

132

Volcano seismology  

USGS Publications Warehouse

A fundamental goal of volcano seismology is to understand active magmatic systems, to characterize the configuration of such systems, and to determine the extent and evolution of source regions of magmatic energy. Such understanding is critical to our assessment of eruptive behavior and its hazardous impacts. With the emergence of portable broadband seismic instrumentation, availability of digital networks with wide dynamic range, and development of new powerful analysis techniques, rapid progress is being made toward a synthesis of high-quality seismic data to develop a coherent model of eruption mechanics. Examples of recent advances are: (1) high-resolution tomography to image subsurface volcanic structures at scales of a few hundred meters; (2) use of small-aperture seismic antennas to map the spatio-temporal properties of long-period (LP) seismicity; (3) moment tensor inversions of very-long-period (VLP) data to derive the source geometry and mass-transport budget of magmatic fluids; (4) spectral analyses of LP events to determine the acoustic properties of magmatic and associated hydrothermal fluids; and (5) experimental modeling of the source dynamics of volcanic tremor. These promising advances provide new insights into the mechanical properties of volcanic fluids and subvolcanic mass-transport dynamics. As new seismic methods refine our understanding of seismic sources, and geochemical methods better constrain mass balance and magma behavior, we face new challenges in elucidating the physico-chemical processes that cause volcanic unrest and its seismic and gas-discharge manifestations. Much work remains to be done toward a synthesis of seismological, geochemical, and petrological observations into an integrated model of volcanic behavior. Future important goals must include: (1) interpreting the key types of magma movement, degassing and boiling events that produce characteristic seismic phenomena; (2) characterizing multiphase fluids in subvolcanic regimes and determining their physical and chemical properties; and (3) quantitatively understanding multiphase fluid flow behavior under dynamic volcanic conditions. To realize these goals, not only must we learn how to translate seismic observations into quantitative information about fluid dynamics, but we also must determine the underlying physics that governs vesiculation, fragmentation, and the collapse of bubble-rich suspensions to form separate melt and vapor. Refined understanding of such processes-essential for quantitative short-term eruption forecasts-will require multidisciplinary research involving detailed field measurements, laboratory experiments, and numerical modeling.

Chouet, B.

2003-01-01

133

Eruptive history and tectonic setting of Medicine Lake Volcano, a large rear-arc volcano in the southern Cascades  

Microsoft Academic Search

Medicine Lake Volcano (MLV), located in the southern Cascades ?55 km east-northeast of contemporaneous Mount Shasta, has been found by exploratory geothermal drilling to have a surprisingly silicic core mantled by mafic lavas. This unexpected result is very different from the long-held view derived from previous mapping of exposed geology that MLV is a dominantly basaltic shield volcano. Detailed mapping shows

Julie M. Donnelly-Nolan; Timothy L. Grove; Marvin A. Lanphere; Duane E. Champion; David W. Ramsey

2008-01-01

134

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

135

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

136

Volcanoes: Nature's Caldrons Challenge Geochemists.  

ERIC Educational Resources Information Center

Reviews various topics and research studies on the geology of volcanoes. Areas examined include volcanoes and weather, plate margins, origins of magma, magma evolution, United States Geological Survey (USGS) volcano hazards program, USGS volcano observatories, volcanic gases, potassium-argon dating activities, and volcano monitoring strategies.…

Zurer, Pamela S.

1984-01-01

137

Waveform inversion of very long period impulsive signals associated with magmatic injection beneath Kilauea Volcano, Hawaii  

Microsoft Academic Search

We use data from broadband seismometers deployed around the summit of Kilauea Volcano to quantify the mechanism associated with a transient in the flow of magma feeding the east rift eruption of the volcano. The transient is marked by rapid inflation of the Kilauea summit peaking at 22 murad 4.5 hours after the event onset, followed by slow deflation over

Takao Ohminato; Bernard A. Chouet; Phillip Dawson; Sharon Kedar

1998-01-01

138

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

139

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.

140

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

141

Iceland's Grímsvötn volcano erupts  

NASA Astrophysics Data System (ADS)

About 13 months after Iceland's Eyjafjallajökull volcano began erupting on 14 April 2010, which led to extensive air traffic closures over Europe, Grímsvötn volcano in southeastern took its turn. Iceland's most active volcano, which last erupted in 2004 and lies largely beneath the Vatnajökull ice cap, began its eruption activity on 21 May, with the ash plume initially reaching about 20 kilometers in altitude, according to the Icelandic Meteorological Office. Volcanic ash from Grímsvötn has cancelled hundreds of airplane flights and prompted U.S. president Barack Obama to cut short his visit to Ireland. As Eos went to press, activity at the volcano was beginning to subside.

Showstack, Randy

2011-05-01

142

Alaska Volcano Observatory Monitoring Station  

USGS Multimedia Gallery

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

143

Unzen Volcano, Japan  

NASA Technical Reports Server (NTRS)

This is a space radar image of the area around the Unzen volcano, on the west coast of Kyushu Island in southwestern Japan. Unzen, which appears in this image as a large triangular peak with a white flank near the center of the peninsula, has been continuously active since a series of powerful eruptions began in 1991. 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 93rd orbit on April 15, 1994. The image shows an area 41.5 kilometers by 32.8 kilometers (25.7 miles by 20.3 miles) that is centered at 32.75 degrees north latitude and 130.15 degrees east longitude. North is toward the upper left of the image. The radar illumination is from the top of the image. The colors in this image were obtained using the following radar channels: red represents the L-band (vertically transmitted and received); green represents the average of L-band and C-band (vertically transmitted and received); blue represents the C-band (vertically transmitted and received). Unzen is one of 15 'Decade' volcanoes identified by the scientific community as posing significant potential threats to large local populations. The city of Shimabara sits along the coast at the foot of Unzen on its east and northeast sides. At the summit of Unzen a dome of thick lava has been growing continuously since 1991. Collapses of the sides of this dome have generated deadly avalanches of hot gas and rock known as pyroclastic flows. Volcanologists can use radar image data to monitor the growth of lava domes, to better understand and predict potentially hazardous collapses.

Spaceborne Imaging Radar-C and X-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).

1995-01-01

144

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

145

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

146

Volcano Resources for Educators  

NSDL National Science Digital Library

This site provides an up-to-date list of textual and video educational materials pertaining to volcanoes. The online pamphlets and books, hardcopy books, rental films and videos cover all levels of interest regarding volcanoes. The site furnishes the information or links to information needed to obtain these materials.

147

Iceland: Eyjafjallajökull Volcano  

Atmospheric Science Data Center

... height map   Ash from Iceland's Eyjafjallajökull volcano, viewed here in imagery from the Multi-angle Imaging SpectroRadiometer ... natural-color, nadir (vertical) view of the scene, with the volcano itself located outside the upper left corner of the image. The ash ...

2013-04-17

148

Iceland: Eyjafjallajökull Volcano  

Atmospheric Science Data Center

... to capture a series of images of the Eyjafjallajökull volcano and its erupting ash plume. Figure 1 is a view from MISR's nadir ... The companion image, Figure 2, is a stereo anaglyph (see  Volcano Plume Heights Anaglyph ) generated from the nadir and 46-degree ...

2013-04-17

149

Chaiten Volcano Still Active  

NSDL National Science Digital Library

This Boston Globe news article shows 12 stunning pictures of the Chaiten Volcano erupting in Chile, its first activity in over 9,000 years. The most recent eruptive phase of the volcano began on May 2, 2008, and is ongoing. The site also has a blog of open, public commentary.

150

Volcanoes, Third Edition  

Microsoft Academic Search

It takes confidence to title a smallish book merely ``Volcanoes'' because of the impliction that the myriad facets of volcanism---chemistry, physics, geology, meteorology, hazard mitigation, and more---have been identified and addressed to some nontrivial level of detail. Robert and Barbara Decker have visited these different facets seamlessly in Volcanoes, Third Edition. The seamlessness comes from a broad overarching, interdisciplinary, professional

Christopher J. Nye

1998-01-01

151

Iceland: Eyjafjallajökull Volcano  

Atmospheric Science Data Center

article title:  Eyjafjallajökull Volcano Plume Heights     View ... volcano produced its second major ash plume of 2010 beginning on May 7. Unlike the response to the earlier eruption, which began on April 14, 2010, the reaction to the new plume was better informed. Aircraft were diverted ...

2013-04-17

152

Demise of reef-flat carbonate accumulation with late Holocene sea-level fall: Evidence from Molokai, Hawaii  

USGS Publications Warehouse

Twelve cores from the protected reef-flat of Molokai revealed that carbonate sediment accumulation, ranging from 3 mm year-1 to less than 1 mm year-1, ended on average 2,500 years ago. Modern sediment is present as a mobile surface veneer but is not trapped within the reef framework. This finding is consistent with the arrest of deposition at the end of the mid-Holocene highstand, known locally as the "Kapapa Stand of the Sea," ???2 m above the present datum ca. 3,500 years ago in the main Hawaiian Islands. Subsequent erosion, non-deposition, and/or a lack of rigid binding were probable factors leading to the lack of reef-flat accumulation during the late Holocene sea-level fall. Given anticipated climate changes, increased sedimentation of reef-flat environments is to be expected as a consequence of higher sea level. ?? 2008 Springer-Verlag.

Engels, M.S.; Fletcher, C.H.; Field, M.; Conger, C.L.; Bochicchio, C.

2008-01-01

153

Volcano's Deadly Warning  

NSDL National Science Digital Library

This site highlights the Nova television program Volcano's Deadly Warning broadcast in November of 2002. In addition to a description of the program, which included information on the eruptions of Galeras and Nevado del Ruiz in Columbia and Popocatepetl in Mexico, the site has four other sections. There is an interactive slide show that includes information about ash, lava flow, lava domes, lava, vents, tephra, calderas, lahars, fissures, dikes, and magmas; a section where one can discover the hidden signatures that volcanologists seek in the noise emanating from a restless volcano; a section where Bernard Chouet of the United States Geological Surveys Volcano Hazard Team describes the mysterious seismic signal he discovered that hints when a volcano might blow; and an interview with Dan Miller of the Volcano Disaster Assistance Program discussing their work with other countries, including the success at Mt. Pinatubo in the Philippines in 1991.

154

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.

155

Team investigates activity at Mt. Semeru, Java, volcano  

NASA Astrophysics Data System (ADS)

In February 1994 a large eruption continued a pattern of activity that Mt. Semeru volcano—the highest mountain in Java, Indonesia—has exhibited since 1967. Mt. Semeru lies south of the Tengger Caldera, which encloses the volcano Mt. Bromo. Together, they form one of the largest volcanic complexes in the province of East Java.Although Mt. Semeru is one of the most continuously active volcanos in Indonesia, it has been the subject of few scientific investigations. Observations of the volcano's activity are made from a distance and compiled in monthly and annual reports by the Volcanological Survey of Indonesia (VSI), but the most recent detailed map of the summit region was published in 1938 in the Atlas of the Dutch Colonies.

Hellweg, Peggy; Seidl, Dieter; Brotopuspito, Kirbani Sri; Brüstle, Wolfgang

156

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...

157

The volcanoes of Auckland city  

Microsoft Academic Search

This article considers that portion of the Auckland volcanic field included in the isthmus west of Tamaki Inlet. The volcanoes (late Pleistocene-Recent) are described in four groups: the dominantly tuff-producing volcanoes of the c.entral city area; the mainly effusive volcanoes of Wraitemata lava field; the volcanoes of Manukau lava field and the associated Epsom tuff deposit: and the volcanoes of

E. J. Searle

1962-01-01

158

AVO: Alaska Volcano Observatory  

NSDL National Science Digital Library

This site illustrates the Alaska Volcano Observatory's (AVO) objective to monitor Alaska's volcanoes for the purpose of forecasting volcanic activity and alleviating hazards. AVO's seismometers and satellite imagery allow visitors to obtain current information on selected volcanoes. Because AVO is responsible for volcanic emergencies, people in Alaska can visit the Web site to determine their vulnerability. The site also features AVO's research in geological mapping, modeling of magnetic systems, and development of new instrumentation for predication and interpretation of volcanic unrest. Everyone can appreciate the images of past volcanic eruptions.

159

Anatomy of a Volcano  

NSDL National Science Digital Library

In this interactive activity from NOVA Online, explore the main features of the Nyiragongo volcano, located in the Democratic Republic of Congo, and learn what risks it poses to the 500,000 people who live in its shadow.

2005-12-17

160

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

161

Volcano Watch Satellite Images  

NSDL National Science Digital Library

The University of Wisconsin's Space Science and Engineering Center displays these satellite images of the world's ten most active volcanoes. Users can view images of the Colima Volcano in Central Mexico or Mount Etna in Sicily, Italy. The latest images are updated every half-hour. Also, a Java animation feature splices together the last four images to show a simulation over a two-hour period.

162

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

163

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

164

CO32- concentration and pCO2 thresholds for calcification and dissolution on the Molokai reef flat, Hawaii  

USGS Publications Warehouse

The severity of the impact of elevated atmospheric pCO2 to coral reef ecosystems depends, in part, on how sea-water pCO2 affects the balance between calcification and dissolution of carbonate sediments. Presently, there are insufficient published data that relate concentrations of pCO 2 and CO32- to in situ rates of reef calcification in natural settings to accurately predict the impact of elevated atmospheric pCO2 on calcification and dissolution processes. Rates of net calcification and dissolution, CO32- concentrations, and pCO2 were measured, in situ, on patch reefs, bare sand, and coral rubble on the Molokai reef flat in Hawaii. Rates of calcification ranged from 0.03 to 2.30 mmol CaCO3 m-2 h-1 and dissolution ranged from -0.05 to -3.3 mmol CaCO3 m-2 h-1. Calcification and dissolution varied diurnally with net calcification primarily occurring during the day and net dissolution occurring at night. These data were used to calculate threshold values for pCO2 and CO32- at which rates of calcification and dissolution are equivalent. Results indicate that calcification and dissolution are linearly correlated with both CO32- and pCO2. Threshold pCO2 and CO32- values for individual substrate types showed considerable variation. The average pCO2 threshold value for all substrate types was 654??195 ??atm and ranged from 467 to 1003 ??atm. The average CO32- threshold value was 152??24 ??mol kg-1, ranging from 113 to 184 ??mol kg-1. Ambient seawater measurements of pCO2 and CO32- indicate that CO32- and pCO2 threshold values for all substrate types were both exceeded, simultaneously, 13% of the time at present day atmospheric pCO2 concentrations. It is predicted that atmospheric pCO2 will exceed the average pCO2 threshold value for calcification and dissolution on the Molokai reef flat by the year 2100.

Yates, K.K.; Halley, R.B.

2006-01-01

165

Living With Volcanoes: The USGS Volcano Hazards Program  

NSDL National Science Digital Library

This report summarizes the Volcano Hazards Program of the United States Geological Survey (USGS). Topics include its goals and activities, some key accomplishments, and a plan for future operations. There are also discussions of active and potentially active volcanoes in the U.S., the role of the USGS volcano observatories, prediction of eruptions, and potential danger to aircraft from volcanic plumes.

166

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

167

Volcano seismicity in Alaska  

NASA Astrophysics Data System (ADS)

I examine the many facets of volcano seismicity in Alaska: from the short-lived eruption seismicity that is limited to only the few weeks during which a volcano is active, to the seismicity that occurs in the months following an eruption, and finally to the long-term volcano seismicity that occurs in the years in which volcanoes are dormant. I use the rich seismic dataset that was recorded during the 2009 eruption of Redoubt Volcano to examine eruptive volcano seismicity. I show that the progression of magma through the conduit system at Redoubt could be readily tracked by the seismicity. Many of my interpretations benefited greatly from the numerous other datasets collected during the eruption. Rarely was there volcanic activity that did not manifest itself in some way seismically, however, resulting in a remarkably complete chronology within the seismic record of the 2009 eruption. I also use the Redoubt seismic dataset to study post-eruptive seismicity. During the year following the eruption there were a number of unexplained bursts of shallow seismicity that did not culminate in eruptive activity despite closely mirroring seismic signals that had preceded explosions less than a year prior. I show that these episodes of shallow seismicity were in fact related to volcanic processes much deeper in the volcanic edifice by demonstrating that earthquakes that were related to magmatic activity during the eruption were also present during the renewed shallow unrest. These results show that magmatic processes can continue for many months after eruptions end, suggesting that volcanoes can stay active for much longer than previously thought. In the final chapter I characterize volcanic earthquakes on a much broader scale by analyzing a decade of continuous seismic data across 46 volcanoes in the Aleutian arc to search for regional-scale trends in volcano seismicity. I find that volcanic earthquakes below 20 km depth are much more common in the central region of the arc than they are in the eastern and western regions. I tie these observations to trends in magma geochemistry and regional tectonic features, and present two hypotheses to explain what could control volcanism in the Aleutian arc.

Buurman, Helena

168

Michigan Technological University Volcanoes Page  

NSDL National Science Digital Library

This site offers links to current volcanic activity reports, volcanic hazards mitigation, information on Central American volcanoes, remote sensing of volcanoes, volcanologic research in online journals, and more. There are also links to a site with information on becoming a volcanologist, and a comics page of volcano humor.

169

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...

170

Earthquakes and Volcanoes  

NSDL National Science Digital Library

This activity has students compare maps of plate tectonics with population density maps and to analyze what these maps imply about the relationship between population and seismic hazards. Students will read about and discuss the theory of plate tectonics, map the regions of the United States that are most susceptible to earthquakes and those that have volcanoes, and list the states that lie on plate boundaries. In addition, they will look at a population density map to determine if people avoid living in areas at high risk for earthquakes and volcanoes. Students will also research specific volcanoes or earthquake zones and write pretend letters to residents of these areas describing the risks. This site also contains suggestions for assessment and ideas for extending the lesson.

2001-01-01

171

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

172

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.

173

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

NASA Astrophysics Data System (ADS)

Taal 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

174

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

175

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

176

Iceland: Eyjafjallajökull Volcano  

Atmospheric Science Data Center

... of the plume features between camera views. A quantitative computer analysis is necessary to separate out wind and height (see  Volcano ... NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Science Mission Directorate, Washington, D.C. The Terra spacecraft is managed ...

2013-04-17

177

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

178

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.

2012-08-03

179

What Are Volcano Hazards?  

MedlinePLUS

... of Mount St. Helens, Washington, fell over an area of 22,000 square miles in the Western United States. Heavy ash fall can collapse buildings, and even minor ash fall can damage crops, electronics, and machinery. Volcanic Gases Volcanoes emit gases during eruptions. Even when a ...

180

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

181

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

182

Nyiragongo volcano, Congo, Anaglyph, SRTM / Landsat  

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 stereoscopic (anaglyph) visualization combines a Landsat satellite image and an elevation model from the Shuttle Radar Topography Mission (SRTM) to provide a view of the volcano, the city of Goma, and surrounding terrain.

Nyiragongo is the steep volcano to the lower right of center, Lake Kivu is at the bottom, and the city of Goma is located along the northeast shore (bottom center). 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 broader Nyamuragira volcano appears to the upper left of Nyiragongo.

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. The cliff at the top center of the image is the western edge of the rift. Volcanic activity is common in the rift, and older but geologically recent lava flows (dark in this depiction) are particularly apparent on the flanks of the Nyamuragira volcano.

This anaglyph was produced by first shading an elevation model from data acquired by the Shuttle Radar Topography Mission and blending it with a single band of a Landsat scene. The stereoscopic effect was then created by generating two differing perspectives, one for each eye. When viewed through special glasses, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and the right eye with a blue filter.

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. 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 project by the United States Geological Survey, Earth Resources Observation Systems (EROS) DataCenter, Sioux Falls, S.D.

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 Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise,Washington, D.C.

Size: 43 by 62 kilometers (27 by 39 miles) Location: 1.5 degrees South latitude, 29.3 degrees East longitude Orientation: East-northeast at top Image Data: Landsat Band 4 (near infrared) combined with SRTM shaded relief Original Data Resolution: SRTM 1 arcsecond (30 meters or 98 feet), Landsat 30 meters (98 feet). Date Acquired: February 2000 (SRTM), December 11, 2001 (Landsat)

2002-01-01

183

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

184

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

185

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.

186

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

187

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.

188

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.

189

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

190

Volcanoes and Climate Change  

NSDL National Science Digital Library

Major volcanic eruptions alter the Earth's radiative balance, as volcanic ash and gas clouds absorb terrestrial radiation and scatter a significant amount of the incoming solar radiation, an effect known as "radiative forcing" that can last from two to three years following a volcanic eruption. This results in reduced temperatures in the troposphere, and changes in atmospheric circulation patterns. This site uses text, photographs, and links to related sites to describe volcano-induced climate change.

191

4D volcano gravimetry  

USGS Publications Warehouse

Time-dependent gravimetric measurements can detect subsurface processes long before magma flow leads to earthquakes or other eruption precursors. The ability of gravity measurements to detect subsurface mass flow is greatly enhanced if gravity measurements are analyzed and modeled with ground-deformation data. Obtaining the maximum information from microgravity studies requires careful evaluation of the layout of network benchmarks, the gravity environmental signal, and the coupling between gravity changes and crustal deformation. When changes in the system under study are fast (hours to weeks), as in hydrothermal systems and restless volcanoes, continuous gravity observations at selected sites can help to capture many details of the dynamics of the intrusive sources. Despite the instrumental effects, mainly caused by atmospheric temperature, results from monitoring at Mt. Etna volcano show that continuous measurements are a powerful tool for monitoring and studying volcanoes.Several analytical and numerical mathematical models can beused to fit gravity and deformation data. Analytical models offer a closed-form description of the volcanic source. In principle, this allows one to readily infer the relative importance of the source parameters. In active volcanic sites such as Long Valley caldera (California, U.S.A.) and Campi Flegrei (Italy), careful use of analytical models and high-quality data sets has produced good results. However, the simplifications that make analytical models tractable might result in misleading volcanological inter-pretations, particularly when the real crust surrounding the source is far from the homogeneous/ isotropic assumption. Using numerical models allows consideration of more realistic descriptions of the sources and of the crust where they are located (e.g., vertical and lateral mechanical discontinuities, complex source geometries, and topography). Applications at Teide volcano (Tenerife) and Campi Flegrei demonstrate the importance of this more realistic description in gravity calculations. ?? 2008 Society of Exploration Geophysicists. All rights reserved.

Battaglia, Maurizio; Gottsmann, J.; Carbone, D.; Fernandez, J.

2008-01-01

192

Explosive Eruptions of Kamchatkan Volcanoes in 2013 and Danger to Aviation  

NASA Astrophysics Data System (ADS)

There are 30 active volcanoes in the Kamchatka, and three of them (Sheveluch, Klyuchevskoy, and Karymsky) continuously active. In 2013, five of the Kamchatkan volcanoes - Sheveluch, Klyuchevskoy, Karymsky, Zhupanovsky, and Mutnovsky - had strong and moderate explosive eruptions. 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. 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 2013: on June 26, on October 18, and on December 03: ash plumes rose up to 10 km a.s.l. and extended about 200-400 km, respectively, to the south-west, south-southeast, and north of the volcano. A form of pyroclastic flow deposits with run-out 12 km accompanied these explosive eruptions. Ashfalls occurred at Klyuchi Village (on June 26) and Ivashka Village (on December 03). Activity of the volcano was dangerous to international and local aviation. Klyuchevskoy volcano had two eruptions in 2013: moderate Strombolian explosive eruption from October 14, 2012, till January 15, 2013; and strong Strombolian-Vulcanian explosive and effusive eruption from August 15, 2013, till December 20, 2013. There were four lava flows to effuse on the north-west, west and south-western volcanic flanks. Probably a flank eruption began at the pass between Klyuchevskoy volcano and Kamen volcano on October 06. Culmination of strong Vulcanian explosive activity of the volcano occurred on October 15-20: ash column rose up to 10-12 km a.s.l. and ash plumes extended to the different directions of the volcano according to cyclonic activity in the this area. Phreatic ash plumes on the fronts of lava flows rose up to 5 km a.s.l. Weak ash falls were noted at Klyuchi Village on October 09 and 13, and Mayskoe Village on October 16. Activity of the volcano was dangerous to international and local aviation. Karymsky volcano has been in a state of explosive eruption since 1996. The moderate explosive eruption continued during all 2013. Activity of the volcano was dangerous to local aviation. Moderate explosive phreatic eruption of Zhupanovsky volcano occurred on October 23-24, 2013. Ash explosions rose up to 5 km a.s.l. and ash plumes extended for about 120 km mainly to the east and south-east of the volcano. A thickness of ash was about 10 cm at the volcano summit. Activity of the volcano was dangerous to local aviation. Several moderate phreatic explosions were noted by observers at Active crater of Mutnovsky volcano on July 03. Ash plumes were not noted at satellite images.

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

2014-05-01

193

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

194

Pairing the Volcano  

E-print Network

Isogeny volcanoes are graphs whose vertices are elliptic curves and whose edges are $\\ell$-isogenies. Algorithms allowing to travel on these graphs were developed by Kohel in his thesis (1996) and later on, by Fouquet and Morain (2001). However, up to now, no method was known, to predict, before taking a step on the volcano, the direction of this step. Hence, in Kohel's and Fouquet-Morain algorithms, many steps are taken before choosing the right direction. In particular, ascending or horizontal isogenies are usually found using a trial-and-error approach. In this paper, we propose an alternative method that efficiently finds all points $P$ of order $\\ell$ such that the subgroup generated by $P$ is the kernel of an horizontal or an ascending isogeny. In many cases, our method is faster than previous methods. This is an extended version of a paper published in the proceedings of ANTS 2010. In addition, we treat the case of 2-isogeny volcanoes and we derive from the group structure of the curve and the pairing ...

Ionica, Sorina

2011-01-01

195

Volcanoes and climate  

NASA Technical Reports Server (NTRS)

The evidence that volcanic eruptions affect climate is reviewed. Single explosive volcanic eruptions cool the surface by about 0.3 C and warm the stratosphere by several degrees. Although these changes are of small magnitude, there have been several years in which these hemispheric average temperature changes were accompanied by severely abnormal weather. An example is 1816, the "year without summer" which followed the 1815 eruption of Tambora. In addition to statistical correlations between volcanoes and climate, a good theoretical understanding exists. The magnitude of the climatic changes anticipated following volcanic explosions agrees well with the observations. Volcanoes affect climate because volcanic particles in the atmosphere upset the balance between solar energy absorbed by the Earth and infrared energy emitted by the Earth. These interactions can be observed. The most important ejecta from volcanoes is not volcanic ash but sulfur dioxide which converts into sulfuric acid droplets in the stratosphere. For an eruption with its explosive magnitude, Mount St. Helens injected surprisingly little sulfur into the stratosphere. The amount of sulfuric acid formed is much smaller than that observed following significant eruptions and is too small to create major climatic shifts. However, the Mount St. Helens eruption has provided an opportunity to measure many properties of volcanic debris not previously measured and has therefore been of significant value in improving our knowledge of the relations between volcanic activity and climate.

Toon, O. B.

1982-01-01

196

Cascades Volcano Observatory: Educational Outreach  

NSDL National Science Digital Library

Located in Vancouver, Washington, the Cascades Volcano Observatory monitors and reports on volcanic activity in the area and around the country. The related Educational Outreach Web site is provided by the US Geological Survey. Visitors will find information on current volcanic activity and news, what to do if a volcano erupts, volcano terminology, America's volcanic history, how the Cascade range got their names, volcano questions and answers, and much more. Other features of the site include activities and fun "stuff," posters and videos, and many outside links.

197

Geochemical fingerprint of the primary magma composition in the marine tephras originated from the Baegdusan and Ulleung volcanoes  

NASA Astrophysics Data System (ADS)

The intraplate Baegdusan (Changbai) and Ulleung volcanoes located on the border of China, North Korea, and East/Japan Sea, respectively, have been explained by appeals to both hotspots and asthenospheric mantle upwelling (wet plume) caused by the stagnant Pacific plate. To understand the origin of the Baegdusan and Ulleung volcanism, we performed geochemical analyses on the tephra deposits in the East/Japan Sea basins originating from the Baegdusan and Ulleung volcanoes. The volcanic glass in the tephra from the Baegdusan and Ulleung volcanoes ranged from alkaline trachyte to peralkaline rhyolite and from phonolite to trachyte, respectively. The tephra from the two intraplate volcanoes showed highly enriched incompatible elements, such as Tb, Nb, Hf, and Ta, distinct from those of the ordinary arc volcanoes of the Japanese islands. The straddle distribution of the Th/Yb and Ta/Yb ratios of the tephra deposits from the Baegdusan volcano may originate from the alkali basaltic magma resulting from mixing between the wet plume from the stagnant Pacific plate in the transition zone and the overlying shallow asthenospheric mantle. In contrast, the deposits from the Ulleung volcano show a minor contribution of the stagnant slab to the basaltic magma, implying either partial melting of a more enriched mantle, smaller degrees of partial melting of a garnet-bearing mantle source, or a combination of both processes as the magma genesis. Our study indicated that the Baegdusan and Ulleung volcanoes have different magma sources and evolutionary histories.

Lim, Chungwan; Kim, Seonyoung; Lee, Changyeol

2014-12-01

198

Predictability of volcano eruption: Lessons from a basaltic effusive volcano  

Microsoft Academic Search

Volcano eruption forecast remains a challenging and controversial problem despite the fact that data from volcano monitoring significantly increased in quantity and quality during the last decades. This study uses pattern recognition techniques to quantify the predictability of the 15 Piton de la Fournaise (PdlF) eruptions in the 1988–2001 period using increase of the daily seismicity rate as a precursor.

Jean-Robert Grasso; Ilya Zaliapin

2004-01-01

199

The composition and sources of magmas of Changbaishan Tianchi volcano (China-North Korea)  

NASA Astrophysics Data System (ADS)

The Changbaishan Tianchi volcano is the greatest stratovolcano within the bounds of the Late Cenozoic intraplate volcanic province of East Asia. Changbaishan Tianchi volcanic cone consists mostly of trachytes and pantellerites. It was found that the lavas composing the shield platform of Changbaishan Tianchi volcano are weakly differentiated basic rocks whose geochemical characteristics are generally similar. All the alkaline salic rocks composing the cone of the volcano are characterized by conformable normalized trace element patterns. The concentrations of rare-earth elements in these rocks are high and amount up to 1000 ppm. The character of the distribution of trace elements in the basic rocks of Changbaishan Tianchi volcano is close to that in the OIB-type basalts. Within the series from basalts to pantellerites, the rocks are enriched in REE and zirconium, but depleted in barium, strontium, and europium. According to the obtained geochemical data, it was shown that the rock series of Changbaishan Tianchi volcano, varying from basalts to trachytes and pantellerites comprises compositions geochemically interrelated by the processes of crystal fractionation. The parental magma for the rocks of the volcano was derived from plume sources of the same type as those of OIB and sources of the Late Cenozoic intraplate province of East Asia.

Andreeva, O. A.; Yarmolyuk, V. V.; Andreeva, I. A.; Ji, J. Q.; Li, W. R.

2014-05-01

200

Remote sensing of Italian volcanos  

NASA Technical Reports Server (NTRS)

The results of a July 1986 remote sensing campaign of Italian volcanoes are reviewed. The equipment and techniques used to acquire the data are described and the results obtained for Campi Flegrei and Mount Etna are reviewed and evaluated for their usefulness for the study of active and recently active volcanoes.

Bianchi, R.; Casacchia, R.; Coradini, A.; Duncan, A. M.; Guest, J. E.; Kahle, A.; Lanciano, P.; Pieri, D. C.; Poscolieri, M.

1990-01-01

201

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

202

Italian Volcano Supersites  

NASA Astrophysics Data System (ADS)

Volcanic eruptions are among the geohazards that may have a substantial economic and social impact, even at worldwide scale. Large populated regions are prone to volcanic hazards worldwide. Even local phenomena may affect largely populated areas and in some cases even megacities, producing severe economic losses. On a regional or global perspective, large volcanic eruptions may affect the climate for years with potentially huge economic impacts, but even relatively small eruptions may inject large amounts of volcanic ash in the atmosphere and severely affect air traffic over entire continents. One of main challenges of the volcanological community is to continuously monitor and understand the internal processes leading to an eruption, in order to give substantial contributions to the risk reduction. Italian active volcanoes constitute natural laboratories and ideal sites where to apply the cutting-edge volcano observation systems, implement new monitoring systems and to test and improve the most advanced models and methods for investigate the volcanic processes. That's because of the long tradition of volcanological studies resulting into long-term data sets, both in-situ and from satellite systems, among the most complete and accurate worldwide, and the large spectrum of the threatening volcanic phenomena producing high local/regional/continental risks. This contribution aims at presenting the compound monitoring systems operating on the Italian active volcanoes, the main improvements achieved during the recent studies direct toward volcanic hazard forecast and risk reductions and the guidelines for a wide coordinated project aimed at applying the ideas of the GEO Supersites Initiative at Mt. Etna and Campi Flegrei / Vesuvius areas.

Puglisi, G.

2011-12-01

203

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  

NASA Astrophysics Data System (ADS)

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 Information Systems, this research investigates the effects of mangrove introduction on sediment dynamics and coastal change on south Molokai throughout the 20th century and provides a baseline of mangrove distribution, a detailed record of shoreline change rates, and a chronological history of island land use and environmental change. Monitoring of coastal change associated with mangroves is essential to understanding how natural coastal ecosystems react to alien species introductions and adapt overall to changing climatic regimes. Comparing the accuracy of various remote sensing instruments and processing techniques, this study has shown that the remote sensing with modern airborne and satellite sensors offers an effective management tool for mapping baseline conditions and monitoring change in remote island environments like that on the south coast of Molokai. Shoreline change assessment found that shoreline change rates on the island's south coast varied both alongshore and through time and that the dominant change has been one of progradation. Rates of change peaked in the early part of the 20th century and have since decayed exponentially over time. Changing land use practices coupled with the introduction of invasive species may have strongly influenced observed variability in rates of coastal change. Field observations and sediment analysis suggest that sediment transfer across the coastal boundary on the mangrove-fringed south coast is relatively limited and appears to be mainly event-driven. For shallow, reef-fringed, coastal regions vulnerable to submergence with a scenario of rising sea level and where land use practices and variable seasonal climate affect sediment delivery to the coast, mangroves are instrumental in trapping terrestrial sediment at the shoreline, play an important role in determining local sources and sinks of coastal sediment, and may contribute to the overall health and sustainability of nearshore reef resources.

D'Iorio, Margaret Mary

204

Volcano Homework Assignment  

NSDL National Science Digital Library

In this and similar assignments students have to download quantitative natural hazard data from the Internet, load it into a spreadsheet, rank order the data, calculate recurrence times and plot the result on a log-log graph. They then interpret this graph in terms of the recurrence time of hazard events of different sizes. In many cases this includes comparing results from two different features (volcanoes, faults, rivers, etc.) Uses online and/or real-time data Addresses student fear of quantitative aspect and/or inadequate quantitative skills Uses geophysics to solve problems in other fields Addresses student misconceptions

Steven Jaume

205

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.

206

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

207

Submarine volcanoes along the Aegean volcanic arc  

NASA Astrophysics Data System (ADS)

The Aegean volcanic arc has been investigated along its offshore areas and several submarine volcanic outcrops have been discovered in the last 25 years of research. The basic data including swath bathymetric maps, air-gun profiles, underwater photos and samples analysis have been presented along the four main volcanic groups of the arc. The description concerns: (i) Paphsanias submarine volcano in the Methana group, (ii) three volcanic domes to the east of Antimilos Volcano and hydrothermal activity in southeast Milos in the Milos group, (iii) three volcanic domes east of Christiana and a chain of about twenty volcanic domes and craters in the Kolumbo zone northeast of Santorini in the Santorini group and (iv) several volcanic domes and a volcanic caldera together with very deep slopes of several volcanic islands in the Nisyros group. The tectonic structure of the volcanic centers is described and related to the geometry of the arc and the neotectonic graben structures that usually host them. The NE-SW direction is dominant in the Santorini and Nisyros volcanic groups, located at the eastern part of the arc, where strike-slip is also present, whereas NW-SE direction dominates in Milos and Methana at the western part, where co-existence of E-W disrupting normal faults is observed. The volcanic relief reaches 1100-1200 m in most cases. This is produced from the outcrops of the volcanic centers emerging usually at 400-600 m depth and ending either below sea level or at high altitudes of 600-700 m on the islands. Hydrothermal activity at relatively high temperatures observed in Kolumbo is remarkable whereas low temperature phenomena have been detected in the Santorini caldera around Kameni islands and in the area southeast of Milos. In Methana and Nisyros, hydrothermal activity seems to be limited in the coastal areas without other offshore manifestations.

Nomikou, Paraskevi; Papanikolaou, Dimitrios; Alexandri, Matina; Sakellariou, Dimitris; Rousakis, Grigoris

2013-06-01

208

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

209

Anfrageoptimierung in Volcano und Bjorn Scheuermann  

E-print Network

Anfrageoptimierung in Volcano und Cascades Bj¨orn Scheuermann Vortrag im Rahmen des Seminars Datenbanken, WS 03/04 Anfrageoptimierung in Volcano und Cascades ­ p.1/23 #12;Zielsetzung Entwicklung von ¨angig von konkretem Datenmodell Anfrageoptimierung in Volcano und Cascades ­ p.2/23 #12;Volcano

Mannheim, Universität

210

High-resolution seismic tomography of compressional wave velocity structure at Newberry Volcano, Oregon Cascade Range  

SciTech Connect

Compressional wave velocity structure is determined for the upper crust beneath Newberry Volcano, central Oregon, using a high-resolution active-source seismic-tomography method. Newberry Volcano is a bimodal shield volcano east of the axis of the Cascade Range. It is associated both with the Cascade Range and with northwest migrating silicic volcanism in southeast Oregon. High-frequency (approx.7 Hz) crustal phases, nominally Pg and a midcrustal reflected phase, travel upward through a target volume beneath Newberry Volcano to a dense array of 120 seismographs. This arrangement is limited by station spacing to 1- to 2-km resolution in the upper 5 to 6 km of the crust beneath the volcano's summit caldera. The experiment tests the hypothesis that Cascade Range volcanoes are underlain only by small magma chambers. A small low-velocity anomaly delineated abosut 3 km below the summit caldera supports this hypothesis for Newberry Volcano and is interpreted as a possible magma chamber of a few to a few tens of km/sup 3/ in volume. A ring-shaped high-velocity anomaly nearer the surface coincides with the inner mapped ring fractures of the caldera. It also coincides with a circular gravity high, and we interpret it as largely subsolidus silicic cone sheets. The presence of this anomaly and of silicic vents along the ring fractures suggests that the fractures are a likely eruption path between the small magma chamber and the surface.

Achauer, U.; Evans, J.R.; Stauber, D.A.

1988-09-10

211

A Preliminary Study of Hazus-MH Volcano for Korea  

NASA Astrophysics Data System (ADS)

This presentation will introduce our design to develop a volcano risk modeling capacity within the Hazus-MH loss estimation framework. In particular, we will present how to build fragility curves within the Hazus-MH framework for loss estimation from volcanoes. This capability is designed to analyze the risk from volcanic hazards in Korea. The Korean peninsula has Mt. Baekdu in North Korea, which will soon enter an active phase, according to some volcanologists. The anticipated eruption will be explosive given the viscous and grassy silica-rich magma, and is expected to be one of the largest in recent millennia. We aim to assess the impacts of this eruption, in particular to South Korea. There are several types of hazards related to volcanic eruption, including ash, pyroclastic flows, volcanic floods and earthquakes. However, our initial efforts focus on modeling losses from volcanic ash. The proposed volcanic ash model is anticipated to be used to estimate losses caused by yellow dust in East Asia as well. Also, many countries, which are exposed to potentially dangerous volcanoes, can benefit from the proposed Hazus-MH Volcano risk model. Acknowledgement: this research was supported by a grant [NEMA-BAEKDUSAN-2012-1-3] from the Volcanic Disaster Preparedness Research Center sponsored by National Emergency Management Agency of Korea. We would like to thank Federal Emergency Management Agency which develops Hazus-MH and allows the international use of Hazus-MH.

Yu, S.; An, H.; Oh, J.

2013-12-01

212

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

213

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

214

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

215

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

NASA Astrophysics Data System (ADS)

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.

2006-07-01

216

Volcano Hazards at Fuego and Acatenango, GuatemalaVolcano Hazards at Fuego and Acatenango, GuatemalaVolcano Hazards at Fuego and Acatenango, GuatemalaVolcano Hazards at Fuego and Acatenango, GuatemalaVolcano Hazards at Fuego and Acatenango, Guatemala 1111  

E-print Network

Volcano Hazards at Fuego and Acatenango, GuatemalaVolcano Hazards at Fuego and Acatenango, GuatemalaVolcano Hazards at Fuego and Acatenango, GuatemalaVolcano Hazards at Fuego and Acatenango, GuatemalaVolcano Hazards at Fuego and Acatenango, Guatemala 11111 Open-File Report 01­431Open-File Report 01

Rose, William I.

217

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

218

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

219

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

220

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

221

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

222

Counterfactual Volcano Hazard Analysis  

NASA Astrophysics Data System (ADS)

The historical database of past disasters is a cornerstone of catastrophe risk assessment. Whereas disasters are fortunately comparatively rare, near-misses are quite common for both natural and man-made hazards. The word disaster originally means 'an unfavourable aspect of a star'. Except for astrologists, disasters are no longer perceived fatalistically as pre-determined. Nevertheless, to this day, historical disasters are treated statistically as fixed events, although in reality there is a large luck element involved in converting a near-miss crisis situation into a disaster statistic. It is possible to conceive a stochastic simulation of the past to explore the implications of this chance factor. Counterfactual history is the exercise of hypothesizing alternative paths of history from what actually happened. Exploring history from a counterfactual perspective is instructive for a variety of reasons. First, it is easy to be fooled by randomness and see regularity in event patterns which are illusory. The past is just one realization of a variety of possible evolutions of history, which may be analyzed through a stochastic simulation of an array of counterfactual scenarios. In any hazard context, there is a random component equivalent to dice being rolled to decide whether a near-miss becomes an actual disaster. The fact that there may be no observed disaster over a period of time may belie the occurrence of numerous near-misses. This may be illustrated using the simple dice paradigm. Suppose a dice is rolled every month for a year, and an event is recorded if a six is thrown. There is still an 11% chance of no events occurring during the year. A variety of perils may be used to illustrate the use of near-miss information within a counterfactual disaster analysis. In the domain of natural hazards, near-misses are a notable feature of the threat landscape. Storm surges are an obvious example. Sea defences may protect against most meteorological scenarios. However, if a major storm surge happens to arrive at a high astronomical tide, sea walls may be overtopped and flooding may ensue. In the domain of geological hazards, periods of volcanic unrest may generate precursory signals suggestive of imminent volcanic danger, but without leading to an actual eruption. Near-miss unrest periods provide vital evidence for assessing the dynamics of volcanoes close to eruption. Where the volcano catalogue has been diligently revised to include the maximum amount of information on the phenomenology of unrest periods, dynamic modelling and hazard assessment may be significantly refined. This is illustrated with some topical volcano hazard examples, including Montserrat and Santorini.

Woo, Gordon

2013-04-01

223

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

224

Eruptive history and tectonic setting of Medicine Lake Volcano, a large rear-arc volcano in the southern Cascades  

USGS Publications Warehouse

Medicine Lake Volcano (MLV), located in the southern Cascades ??? 55??km east-northeast of contemporaneous Mount Shasta, has been found by exploratory geothermal drilling to have a surprisingly silicic core mantled by mafic lavas. This unexpected result is very different from the long-held view derived from previous mapping of exposed geology that MLV is a dominantly basaltic shield volcano. Detailed mapping shows that < 6% of the ??? 2000??km2 of mapped MLV lavas on this southern Cascade Range shield-shaped edifice are rhyolitic and dacitic, but drill holes on the edifice penetrated more than 30% silicic lava. Argon dating yields ages in the range ??? 475 to 300??ka for early rhyolites. Dates on the stratigraphically lowest mafic lavas at MLV fall into this time frame as well, indicating that volcanism at MLV began about half a million years ago. Mafic compositions apparently did not dominate until ??? 300??ka. Rhyolite eruptions were scarce post-300??ka until late Holocene time. However, a dacite episode at ??? 200 to ??? 180??ka included the volcano's only ash-flow tuff, which was erupted from within the summit caldera. At ??? 100??ka, compositionally distinctive high-Na andesite and minor dacite built most of the present caldera rim. Eruption of these lavas was followed soon after by several large basalt flows, such that the combined area covered by eruptions between 100??ka and postglacial time amounts to nearly two-thirds of the volcano's area. Postglacial eruptive activity was strongly episodic and also covered a disproportionate amount of area. The volcano has erupted 9 times in the past 5200??years, one of the highest rates of late Holocene eruptive activity in the Cascades. Estimated volume of MLV is ??? 600??km3, giving an overall effusion rate of ??? 1.2??km3 per thousand years, although the rate for the past 100??kyr may be only half that. During much of the volcano's history, both dry HAOT (high-alumina olivine tholeiite) and hydrous calcalkaline basalts erupted together in close temporal and spatial proximity. Petrologic studies indicate that the HAOT magmas were derived by dry melting of spinel peridotite mantle near the crust mantle boundary. Subduction-derived H2O-rich fluids played an important role in the generation of calcalkaline magmas. Petrology, geochemistry and proximity indicate that MLV is part of the Cascades magmatic arc and not a Basin and Range volcano, although Basin and Range extension impinges on the volcano and strongly influences its eruptive style. MLV may be analogous to Mount Adams in southern Washington, but not, as sometimes proposed, to the older distributed back-arc Simcoe Mountains volcanic field.

Donnelly-Nolan, J. M.; Grove, T.L.; Lanphere, M.A.; Champion, D.E.; Ramsey, D.W.

2008-01-01

225

Predictability of Volcano Eruption: lessons from a basaltic effusive volcano  

Microsoft Academic Search

Volcano eruption forecast remains a challenging and controversial problem\\u000adespite the fact that data from volcano monitoring significantly increased in\\u000aquantity and quality during the last decades.This study uses pattern\\u000arecognition techniques to quantify the predictability of the 15 Piton de la\\u000aFournaise (PdlF) eruptions in the 1988-2001 period using increase of the daily\\u000aseismicity rate as a precursor. Lead

Jean-Robert Grasso; Ilya Zaliapin

2003-01-01

226

Monitoring Active Volcanoes  

NASA Astrophysics Data System (ADS)

Monitoring volcanoes is a surprisingly controversial enterprise. Some volcanologists argue that monitoring promises too much and delivers too little for risk mitigation. They trust only strict land-use measures (and accompanying high insurance premiums in risky zones) and urge that funds be used for public education and awareness rather than for instrumental monitoring. Others claim that monitoring is more akin to Brownian motion than to science: lots of action but little net progress. Still other volcanologists acknowledge the potential value of monitoring for prediction and warning but despair at the difficulty of it all. And, finally, some shy from surveillance, fearing the legal consequences of a failed monitoring effort during these litigious times. They wonder, “Will I be sued if an eruption is not foreseen or if an instrument fails at a critical time?”

Swanson, Don

227

Lung problems and volcano smog  

MedlinePLUS

... a volcano react with oxygen, moisture, dust, and sunlight in the atmosphere. Volcanic smog can irritate the ... is sulfur dioxide) react with oxygen, moisture, and sunlight in the atmosphere to form a type of ...

228

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.

Elaine Silva Mangiante

2006-12-01

229

The Ice Piston, Redoubt Volcano  

USGS Multimedia Gallery

The Ice Piston with Ash, Redoubt Volcano, Alaska. This photo was taken on March 21, 2009, the day before Redoubt first erupted. The glacier that filled the crater was collapsing because of the increase in ground temperature underneath....

230

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.

231

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...

232

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...

233

Mud volcanoes in deepwater Nigeria  

Microsoft Academic Search

Detailed study of 3D seismic data from deepwater Nigeria has revealed the presence of features interpreted to be mud volcanoes. They occur in an upper slope environment seen as 1–2km circular features at the seabed. Seabed cores from the mud volcanoes contain oil, gas and sand\\/shale–clast content richer than the seabed background. Pliocene fossils have been identified in the cores,

K Graue

2000-01-01

234

Paleomagnetism of Paisano Volcano, Texas  

E-print Network

PALEOMAGNETISM OF PAISANO VOLCANO, TEXAS A Thesis by DAVID RYAN Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE December 1988 Major Subject...: Geophysics PALEOMAGNETISM OF PAISANO VOLCANO, TEXAS A Thesis by DAVID RYAN Approved as to style and content by: William W. Sager (Chairman of Committee) Tibor G. Rozgon i (Member) Earl R. Hoskins (Member) Robert J. McCabe (Member) Joe S. Watkins...

Ryan, David

1988-01-01

235

Mount St. Helens and Kilauea volcanoes  

SciTech Connect

Mount St. Helens' eruption has taught geologists invaluable lessons about how volcanoes work. Such information will be crucial in saving lives and property when other dormant volcanoes in the northwestern United States--and around the world--reawaken, as geologists predict they someday will. Since 1912, scientists at the U.S. Geological Survey's Hawaiian Volcano Observatory have pioneered the study of volcanoes through work on Mauna Loa and Kilauea volcanoes on the island of Hawaii. In Vancouver, Wash., scientists at the Survey's Cascades Volcano Observatory are studying the after-effects of Mount St. Helens' catalysmic eruption as well as monitoring a number of other now-dormant volcanoes in the western United States. This paper briefly reviews the similarities and differences between the Hawaiian and Washington volcanoes and what these volcanoes are teaching the volcanologists.

Barrat, J. (Smithsonian Institution, Washington, DC (USA))

1989-01-01

236

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.

237

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.

238

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

239

Fluvial valleys on Martian volcanoes  

NASA Technical Reports Server (NTRS)

Channels and valleys were known on the Martian volcanoes since their discovery by the Mariner 9 mission. Their analysis has generally centered on interpretation of possible origins by fluvial, lava, or viscous flows. The possible fluvial dissection of Martian volcanoes has received scant attention in comparison to that afforded outflow, runoff, and fretted channels. Photointerpretative, mapping, and morphometric studies of three Martian volcanoes were initiated: Ceraunius Tholus, Hecate Tholus, and Alba Patera. Preliminary morphometric results indicate that, for these three volcanoes, valley junction angles increase with decreasing slope. Drainage densities are quite variable, apparently reflecting complex interactions in the landscape-forming factors described. Ages of the Martian volcanoes were recently reinterpreted. This refined dating provides a time sequence in which to evaluate the degradational forms. An anomaly has appeared from the initial study: fluvial valleys seem to be present on some Martian volcanoes, but not on others of the same age. Volcanic surfaces characterized only by high permeability lava flows may have persisted without fluvial dissection.

Baker, Victor R.; Gulick, Virginia C.

1987-01-01

240

Mahukona: The missing Hawaiian volcano  

SciTech Connect

New bathymetric and geochemical data indicate that a seamount west of the island of Hawaii, Mahukona, is a Hawaiian shield volcano. Mahukona has weakly alkalic lavas that are geochemically distinct. They have high {sup 3}He/{sup 4}He ratios (12-21 times atmosphere), and high H{sub 2}O and Cl contents, which are indicative of the early state of development of Hawaiian volcanoes. The He and Sr isotopic values for Mahukona lavas are intermediate between those for lavas from Loihi and Manuna Loa volcanoes and may be indicative of a temporal evolution of Hawaiian magmas. Mahukona volcano became extinct at about 500 ka, perhaps before reaching sea level. It fills the previously assumed gap in the parallel chains of volcanoes forming the southern segment of the Hawaiian hotspot chain. The paired sequence of volcanoes was probably caused by the bifurcation of the Hawaiian mantle plume during its ascent, creating two primary areas of melting 30 to 40 km apart that have persisted for at least the past 4 m.y.

Garcia, M.O.; Muenow, D.W. (Univ. of Hawaii, Honolulu (USA)); Kurz, M.D. (Woods Hole Oceanographic Institution, MA (USA))

1990-11-01

241

Bi-directional volcano-earthquake interaction at Mauna Loa Volcano, Hawaii  

NASA Astrophysics Data System (ADS)

At Mauna Loa volcano, Hawaii, large-magnitude earthquakes occur mostly at the west flank (Kona area), at the southeast flank (Hilea area), and at the east flank (Kaoiki area). Eruptions at Mauna Loa occur mostly at the summit region and along fissures at the southwest rift zone (SWRZ), or at the northeast rift zone (NERZ). Although historic earthquakes and eruptions at these zones appear to correlate in space and time, the mechanisms and implications of an eruption-earthquake interaction was not cleared. Our analysis of available factual data reveals the highly statistical significance of eruption-earthquake pairs, with a random probability of 5-to-15 percent. We clarify this correlation with the help of elastic stress-field models, where (i) we simulate earthquakes and calculate the resulting normal stress change at volcanic active zones of Mauna Loa, and (ii) we simulate intrusions in Mauna Loa and calculate the Coulomb stress change at the active fault zones. Our models suggest that Hilea earthquakes encourage dike intrusion in the SWRZ, Kona earthquakes encourage dike intrusion at the summit and in the SWRZ, and Kaoiki earthquakes encourage dike intrusion in the NERZ. Moreover, a dike in the SWRZ encourages earthquakes in the Hilea and Kona areas. A dike in the NERZ may encourage and discourage earthquakes in the Hilea and Kaoiki areas. The modeled stress change patterns coincide remarkably with the patterns of several historic eruption-earthquake pairs, clarifying the mechanisms of bi-directional volcano-earthquake interaction for Mauna Loa. The results imply that at Mauna Loa volcanic activity influences the timing and location of earthquakes, and that earthquakes influence the timing, location and the volume of eruptions. In combination with near real-time geodetic and seismic monitoring, these findings may improve volcano-tectonic risk assessment.

Walter, T. R.; Amelung, F.

2004-12-01

242

US Geological Survey Volcano Hazards Program  

NSDL National Science Digital Library

The US Geological Survey Volcano Hazards Program website presents its objectives "to advance the scientific understanding of volcanic processes and to lessen the harmful impacts of volcanic activity." The public can explore information on volcano monitoring, warning schemes, and emergency planning. Students and educators can find out about the types, effects, location, and history of volcano hazards. The website offers recent online volcano reports and maps, volcano factsheets, videos, and a photo glossary. Teachers can find online versions of many educational volcano-related books and videos. The website features the volcanic observatories in Alaska, the Cascades, Hawaii, Long Valley, and Yellowstone.

243

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

244

Geometry and structure of the andesitic volcano-detritic deposits: The Merapi case  

NASA Astrophysics Data System (ADS)

Several geological studies have been performed on the volcano-detritic deposits but finally the global overview of the geometry of those is still poorly known. The quick alteration enhances the high heterogeneity of these formations, especially under tropical climate. Better knowledge of the structure of the volcano-sedimentary edifices is capital to understand:i) the geomorphological impacts, as landslides ii) or the hydrogeological processes. The Merapi Mount is an andesitic strato-volcano, located in Central Java and is one of the most active volcanoes in Indonesia. About 500,000 people live in the immediate vicinity of the volcano and are directly subject, not only to the volcanic eruptions but also to the landslide hazards. The East flank of the Merapi presents a complex history and has been relatively spared by the recent volcanic activity; thus, the geomorphology and the structure of the deposit have been driven by the erosion and remobilization processes under equatorial climate. This work contributes to understand the processes of construction, destruction and sedimentation of a complex active strato-volcano and shed light to its geological and geomorphological history. Based on field observations and literature, the specific deposits have been identified. The lithological facies have been described and several cross sections have been done to precise the distinct phases of building edifice, due to old eruptions. Recent field surveys allowed characterizing the dismantling steps and processes of the volcano by erosion and the local to distal sedimentation associated. The East flank has been split in four zones where each formation presents a lateral facies variation depending on the distance from the summit and the age of deposits. Based on the collected data, the size and the three dimensional extension of each deposits has been delimitated. The geological and geomorphological interpretation is proposed through a conceptual model.

Selles, A.; Deffontaines, B.; Hendrayana, H.; Violette, S.

2013-12-01

245

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

246

Space Radar Image of Karisoke & Virunga Volcanoes  

NASA Technical Reports Server (NTRS)

This is a false-color composite of Central Africa, showing the Virunga volcano chain along the borders of Rwanda, Zaire and Uganda. This area is home to the endangered mountain gorillas. The image was acquired on October 3, 1994, on orbit 58 of the space shuttle Endeavour by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR). In this image red is the L-band (horizontally transmitted, vertically received) polarization; green is the C-band (horizontally transmitted and received) polarization; and blue is the C-band (horizontally transmitted and received) polarization. The area is centered at about 2.4 degrees south latitude and 30.8 degrees east longitude. The image covers an area 56 kilometers by 70 kilometers (35 miles by 43 miles). The dark area at the top of the image is Lake Kivu, which forms the border between Zaire (to the right) and Rwanda (to the left). In the center of the image is the steep cone of Nyiragongo volcano, rising 3,465 meters (11,369 feet) high, with its central crater now occupied by a lava lake. To the left are three volcanoes, Mount Karisimbi, rising 4,500 meters (14,800 feet) high; Mount Sabinyo, rising 3,600 meters (12,000 feet) high; and Mount Muhavura, rising 4,100 meters (13,500 feet) high. To their right is Nyamuragira volcano, which is 3,053 meters (10,017 feet) tall, with radiating lava flows dating from the 1950s to the late 1980s. These active volcanoes constitute a hazard to the towns of Goma, Zaire and the nearby Rwandan refugee camps, located on the shore of Lake Kivu at the top left. This radar image highlights subtle differences in the vegetation of the region. The green patch to the center left of the image in the foothills of Karisimbi is a bamboo forest where the mountain gorillas live. The vegetation types in this area are an important factor in the habitat of mountain gorillas. Researchers at Rutgers University in New Jersey and the Dian Fossey Gorilla Fund in London will use this data to produce vegetation maps of the area to aid in their studies of the last 650 mountain gorillas in the world. The faint lines above the bamboo forest are the result of agricultural terracing by the people who live in the region. Spaceborne Imaging Radar-C and X-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

247

Modeling Secular Deformation of Kilauea Volcano, Hawaii  

NASA Astrophysics Data System (ADS)

Kilauea volcano, Hawaii, is a dynamic volcanic and tectonic system that hosts rift intrusions and eruptions, summit inflation/deflation and eruptions, flank earthquakes and slow slip events, as well as quasi-steady flank motion. We seek to identify and characterize the actively deforming structures on Kilauea and study their interactions using a combination of GPS, InSAR, and seismic data. In addition we examine whether the change from summit subsidence to inflation in 2003, led to changes elsewhere in the volcano. We begin by modeling velocities of 16 continuous GPS and 28 campaign GPS sites and mean velocities from three ENVISAT tracks (T93 ascending: 10 acquisitions from 20030120 to 20041115; T200 descending: 13 acquisitions from 20030127 to 20041122, T429 descending: 10 acquisitions from 20030212 to 20041103) between 2003 and 2004, a period lacking major episodic events. We use triangular dislocations to mesh the curving rift zones and décollement. The southwest and east rift zones are continuous through the summit caldera area, where we also include a point center of dilatation beneath the southwest caldera. A décollement beginning about 12 km offshore at seven km depth dips approximately eight degrees northwest to achieving a depth of nine kilometers beneath the summit/rift zone. The décollement mesh continues at a shallower dip beneath the north flank of Kilauea reaching a final depth of 9.5 km beneath the north flank of Kilauea/south flank of Mauna Loa. Kinematic constraints enforce that opening at the base of the rift equal the differential décollement slip across the rift. Future modeling will include tests of Koae and Hilina fault geometries as well as time-dependent modeling of the deformation field.

Sinnett, D. K.; Montgomery-Brown, E. D.; Casu, F.; Segall, P.; Fukushima, Y.; Miklius, A.; Poland, M. P.

2010-12-01

248

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

249

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

250

When mud volcanoes sleep: Insight from seep geochemistry at the Dashgil mud volcano, Azerbaijan  

E-print Network

When mud volcanoes sleep: Insight from seep geochemistry at the Dashgil mud volcano, Azerbaijan A Available online 18 November 2008 Keywords: Dashgil mud volcano Azerbaijan Dormant Methane Water geochemistry a b s t r a c t The worlds >1500 mud volcanoes are normally in a dormant stage due to the short

Mazzini, Adriano

251

REDUCING THE RISK FROM VOLCANO HAZARDS BenefitsofVolcanoMonitoringFarOutweigh  

E-print Network

REDUCING THE RISK FROM VOLCANO HAZARDS BenefitsofVolcanoMonitoringFarOutweigh Costs--TheCaseofMountPinatubo T Villagers fleeing the vicinity of Mount Pinatubo, Philippines, during heavy ash fall from the volcano and the U.S. Geological Survey forecast this eruption, enabling people living near the volcano to evacuate

Torgersen, Christian

252

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] The activity at Mauna Loa volcano, Hawaii, is characterized by eruptive fissures that propagate transfer can explain the observed volcano-earthquake interaction. We examine stress changes due to typical

Amelung, Falk

253

Seismicity characteristics of a potentially active Quaternary volcano: The Tatun Volcano Group, northern Taiwan  

E-print Network

Seismicity characteristics of a potentially active Quaternary volcano: The Tatun Volcano Group Volcano Group (TVG) is located at the northern tip of Taiwan, near the capital Taipei and close to two as an extinct volcano, even though more recent studies suggest that TVG might have been active during the last

Lin, Andrew Tien-Shun

254

When mud volcanoes sleep: Insight from seep geochemistry at the Dashgil mud volcano, Azerbaijan  

E-print Network

When mud volcanoes sleep: Insight from seep geochemistry at the Dashgil mud volcano, Azerbaijan A Available online xxx Keywords: Dashgil mud volcano Azerbaijan Dormant Methane Water geochemistry a b s t r a c t The worlds >1500 mud volcanoes are normally in a dormant stage due to the short duration

Svensen, Henrik

255

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

E-print Network

The changing shapes of active volcanoes: History, evolution, and future challenges for volcano Volcano Observatory, Crater Rim Drive, Hawaii National Park, HI 96718-0051, United States b Department of Earth's active volcanoes. By their very nature, however, the magmatic reservoirs and conduits

256

Understanding Volcano Hazards and Preventing Volcanic Disasters A Science Strategy for the Volcano Hazards Program,  

E-print Network

Understanding Volcano Hazards and Preventing Volcanic Disasters A Science Strategy for the Volcano active volcanoes, the United States is among the most volcanically active countries in the world. During and property through exposure to volcano hazards continue to increase. Moreover, rapid globalization makes U

Torgersen, Christian

257

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

258

Yellowstone Volcano Observatory  

NSDL National Science Digital Library

In 2001, the U.S. Geological Survey, Yellowstone National Park, and the University of Utah entered into an agreement that effectively established the Yellowstone Volcano Observatory. Some of the objectives of the Observatory are "to provide seismic, geodetic, and hydrologic monitoring that enables reliable and timely warnings of possible renewed volcanism and related hazards" and "to improve scientific understanding of tectonic and magmatic processes that influence ongoing seismicity and hydrothermal activity." The Web site itself is divided into several major sections that covering collectively all current volcanic and seismic activity in the region, volcanic history in the area, and frequently asked questions. The section dedicated to volcanic monitoring includes real-time and non real-time data on current conditions, along with a monthly summary. The volcanic history section offers a long-form essay (including representative photos) that provides a general overview of the region's turbulent volcanic and seismic history. Finally, the helpful FAQ section covers such topics as the frequency of volcanic eruptions at Yellowstone and the relationship between volcanism and the geysers and hot springs in Yellowstone. [KMG

Geological Survey (U.S.)

259

Thermal surveillance of volcanoes  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. A systematic aircraft program to monitor changes in the thermal emission from volcanoes of the Cascade Range has been initiated and is being carried out in conjunction with ERTS-1 thermal surveillance experiments. Night overflights by aircraft equipped with thermal infrared scanners sensitive to terrestrial emission in the 4-5.5 and 8-14 micron bands are currently being carried out at intervals of a few months. Preliminary results confirm that Mount Rainier, Mount Baker, Mount Saint Helens, Mount Shasta, and the Lassen area continue to be thermally active, although with the exception of Lassen which erupted between 1914 and 1917, and Mount Saint Helens which had a series of eruptions between 1831 and 1834, there has been no recent eruptive activity. Excellent quality infrared images recorded over Mount Rainier, as recently as April, 1972, show similar thermal patterns to those reported in 1964-1966. Infrared images of Mount Baker recorded in November 1970 and again in April 1972 revealed a distinct array of anomalies 1000 feet below the crater rim and associated with fumaroles or structures permitting convective heat transfer to the surface.

Friedman, J. D. (principal investigator)

1972-01-01

260

Redoubt Volcano Summit Crater During Eruption  

USGS Multimedia Gallery

Redoubt Volcano summit crater during eruption. This was taken just after explosive activity at redoubt ceased. There were still significant gas and steam emissions occurring. Iliamna Volcano to the south of Redoubt is visible in the background....

261

An unusual volcano on Venus  

NASA Technical Reports Server (NTRS)

Materials that issued from an unusual Venusian volcano produced (1) a complex domical structure about 100 km across with thick, broad flow lobes up to 41 wide, (2) an extensive sheet of thick flows, and (3) radar-bright surfaces that extend to 360-400 km from the volcano. Altimetry indicates that the relief of the domical structure is about 0.5-1.1 km. The lobes and flows have prominant regularly spaced ridges about 686-820 m apart. Thick flows with large ridge separations and broad lobes are rare on Venus. The viscosities of these flows were larger than those of most lava flows on Venus. Comparisons of the dimensions of the volcano's lobes with lava flows on earth suggest that the Venusian lavas may have large silica contents. Radar-bright surfaces around the volcano may represent the result of an explosive eruption or very thin deposits of low-viscosity lavas. Thus, the radar-bright surfaces and lavas of the volcano were derived from a magma that differentiated within the crust or mantle of Venus. The differentiation produced (1) a gas-rich low-viscosity phase, (2) high-viscosity lavas, and (3) a residual primary magma.

Moore, H. J.; Plaut, J. J.; Schenk, P. M.; Head, J. W.

1992-01-01

262

Remote sensing of volcanos and volcanic terrains  

NASA Technical Reports Server (NTRS)

The possibility of using remote sensing to monitor potentially dangerous volcanoes is discussed. Thermal studies of active volcanoes are considered along with using weather satellites to track eruption plumes and radar measurements to study lava flow morphology and topography. The planned use of orbiting platforms to study emissions from volcanoes and the rate of change of volcanic landforms is considered.

Mouginis-Mark, Peter J.; Francis, Peter W.; Wilson, Lionel; Pieri, David C.; Self, Stephen; Rose, William I.; Wood, Charles A.

1989-01-01

263

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...

264

The Volcano Optimizer Jan. 29 2003  

E-print Network

The Volcano Optimizer Generator Jan. 29 2003 Presented by Peng Wang in CIS650 Cite: Zhang Da Generator System General "toolkits" for creating customized DBs Exodus (Graefe&DeWitt,87) Volcano (Graefe;4 The Motivation of Volcano High Performance Optimization time Memory consumption for search More Extensibility

Ives, Zachary G.

265

Hydrogen emissions from Erebus volcano, Antarctica  

E-print Network

Hydrogen emissions from Erebus volcano, Antarctica Yves Moussallam1 , Clive Oppenheimer1, 2, 3 of molecular hydrogen (H2) emissions from passively degassing volcanoes has recently been made possible using with SO2, H2O and CO2, in the gas and aerosol plume emitted from the phonolite lava lake at Erebus volcano

Paris-Sud XI, Université de

266

Publications of the Volcano Hazards Program 2007  

E-print Network

Publications of the Volcano Hazards Program 2007 2009 U.S. Department of the Interior U.S. Geological Survey #12;1 The Volcano Hazards Program of the U.S. Geological Survey (USGS) is part are included based on date of publication with no attempt to assign them to Fiscal Year. #12;2 Volcano Hazards

Torgersen, Christian

267

EarthScope: Activity at Augustine Volcano  

NSDL National Science Digital Library

This bulletin provides information on the recent eruptive activity of Augustine Volcano in Alaska. Topics include some history of the volcano, its geologic setting as part of the Aleutian island arc, and earthquake locations as indicators of magma movement. The bulletin is also accompanied by a 360-degree rotation around the volcano and background information on the EarthScope Project.

268

Capulin Volcano National Monument September 7, 2000  

E-print Network

Capulin Volcano National Monument September 7, 2000 Landsat Enhanced Thematic Mapper + (RGB = 4,3,2) Noxious Weeds Inventory and Mapping at Capulin Volcano National Monument, Fort Union National Monument and delineate areas of noxious weeds within Capulin Volcano National Monument and Fort Union National Monument

Nebraska-Lincoln, University of

269

Publications of the Volcano Hazards Program 2004  

E-print Network

Publications of the Volcano Hazards Program 2004 2006 U.S. Department of the Interior U.S. Geological Survey #12;2 The Volcano Hazards Program of the U.S. Geological Survey (USGS) is part are included based on date of publication with no attempt to assign them to Fiscal Year. #12;3 Volcano Hazards

Torgersen, Christian

270

PUBLICATIONS OF THE VOLCANO HAZARDS PROGRAM  

E-print Network

PUBLICATIONS OF THE VOLCANO HAZARDS PROGRAM 1994 - 1998 1999 UNITED STATES DEPARTMENT OF THE INTERIOR UNITED STATES GEOLOGICAL SURVEY Available at: http://volcanoes.usgs.gov/Products/sproducts.html #12;ii The Volcano Hazards Program of the U.S. Geological Survey (USGS) is part of the Geologic

Torgersen, Christian

271

Publications of the Volcano Hazards Program 2005  

E-print Network

Publications of the Volcano Hazards Program 2005 2007 U.S. Department of the Interior U.S. Geological Survey #12;2 The Volcano Hazards Program of the U.S. Geological Survey (USGS) is part are included based on date of publication with no attempt to assign them to Fiscal Year. #12;3 Volcano Hazards

Torgersen, Christian

272

Global Volcano Mortality Risk Distribution Projection: Robinson  

E-print Network

Global Volcano Mortality Risk Distribution Projection: Robinson Mortality risk is found by weighting the value of population exposure to volcanoes for each grid cell by a vulnerability coefficient and Development/The World Bank and Columbia University. Volcano Mortality Risk Deciles 1 st ­4 th 5 th ­7 th 8 th

Columbia University

273

Publications of the Volcano Hazards Program 2006  

E-print Network

Publications of the Volcano Hazards Program 2006 2008 U.S. Department of the Interior U.S. Geological Survey #12;2 The Volcano Hazards Program of the U.S. Geological Survey (USGS) is part are included based on date of publication with no attempt to assign them to Fiscal Year. #12;3 Volcano Hazards

Torgersen, Christian

274

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

275

High resolution seismic attenuation tomography at Medicine Lake Volcano, California  

SciTech Connect

Medicine Lake Volcano, a broad shield volcano about 50km east of Mount Shasta in northern California, produced rhylotic eruptions as recently as 400 years ago. Because of this recent activity it is of considerable interest to producers of geothermal energy. In a joint project sponsored by the Geothermal Research Program of the USGS and the Division of Geothermal and Hydropower Division of the US-DOE, the USGS and LLNL conducted an active seismic experiment designed to explore the area beneath and around the caldera. The experiment of eight explosions detonated in a 50 km radius circle around the volcano recorded on a 11 x 15 km grid of 140 seismographs. The travel time data from the experiment have been inverted for structure and are presented elsewhere in this volume. In this paper we present the results of an inversion for 1/Q structure using t* data in a modified Aki inversion scheme. Although the data are noisy, we find that in general attenuative zones correlate with low velocity zones. In particular, we observe a high 1/Q zone roughly in the center of the caldera at 4 km depth in between two large recent dacite flows. This zone could represent the still molten or partially molten source of the flows.

Zucca, J.J.; Kasameyer, P.W.

1987-07-10

276

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 planet’s interior.

This activity is part of a 60-minute set of activities in which learners, ages 8–13, 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?"

2014-07-15

277

Volcanoes and global catastrophes  

NASA Technical Reports Server (NTRS)

The search for a single explanation for global mass extinctions has let to polarization and the controversies that are often fueled by widespread media attention. The historic record shows a roughly linear log-log relation between the frequency of explosive volcanic eruptions and the volume of their products. Eruptions such as Mt. St. Helens 1980 produce on the order of 1 cu km of tephra, destroying life over areas in the 10 to 100 sq km range, and take place, on the average, once or twice a decade. Eruptions producing 10 cu km take place several times a century and, like Krakatau 1883, destroy life over 100 to 1000 sq km areas while producing clear global atmospheric effects. Eruptions producting 10,000 cu km are known from the Quaternary record, and extrapolation from the historic record suggests that they occur perhaps once in 20,000 years, but none has occurred in historic time and little is known of their biologic effects. Even larger eruptions must also exist in the geologic record, but documentation of their volume becomes increasingly difficult as their age increases. The conclusion is inescapable that prehistoric eruptions have produced catastrophes on a global scale: only the magnitude of the associated mortality is in question. Differentiation of large magma chambers is on a time scale of thousands to millions of years, and explosive volcanoes are clearly concentrated in narrow belts near converging plate margins. Volcanism cannot be dismissed as a producer of global catastrophes. Its role in major extinctions is likely to be at least contributory and may well be large. More attention should be paid to global effects of the many huge eruptions in the geologic record that dwarf those known in historic time.

Simkin, Tom

1988-01-01

278

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

279

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

280

Sunset Crater Volcano National Monument  

NSDL National Science Digital Library

This website of the United States Geological Survey (USGS) and the National Park Service (NPS) is a source of geologic information about Sunset Crater Volcano National Monument. It offers a virtual field trip through the area to learn more about cinder cone volcanics and the history of this region. General volcanic information includes an image gallery of the monument, a brief history of the eruptions in the area, volcano facts, and area earthquake and seismic information. There are links to a large glossary and more geologic details about this area.

281

Nyiragongo volcano, Congo, Pre-eruption Perspective View, SRTM / Landsat  

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 12000 homes were destroyed, and hundreds of thousands were forced to flee the broader community of nearly half a million people. This computer generated visualization combines a Landsat satellite image and an elevation model from the Shuttle Radar Topography Mission (SRTM) to provide a view of both the volcano and the city of Goma, looking slightly east of north.

Nyiragongo is the steep volcano on the right, Lake Kivu is in the foreground, and the city of Goma has a light pink speckled appearance along the shoreline. Nyiragongo peaks at about 3470 meters (11,380 feet) elevation and reaches almost exactly 2000 meters (6560 feet) above Lake Kivu. The shorter but broader Nyamuragira volcano appears in the left background. Topographic expression has been exaggerated vertically by a factor of 1.5 for this visualization.

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, topographic shading derived from the SRTM elevation model was added to the Landsat image, and a false sky was added.

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 project by the United States Geological Survey, Earth Resources Observation Systems (EROS) Data Center, Sioux Falls, S.D.

Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on Feb. 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 Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, D.C.

Size: View width 21 kilometers (13 miles), View distance 42 kilometers (26 miles) Location: 1.5 deg. South lat., 29.3 deg. East lon. Orientation: View east-northeast, 5 degrees below horizontal Image Data: Landsat Bands 3, 2, 1 as red, green, blue, respectively. Original Data Resolution: SRTM 1 arcsecond (30 meters or 98 feet), Landsat 30 meters (98 feet) Date Acquired: February 2000 (SRTM), 11 December 2001 (Landsat)

2002-01-01

282

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.

283

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

284

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

285

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

286

Laboratory volcano geodesy  

NASA Astrophysics Data System (ADS)

Magma transport in volcanic plumbing systems induces surface deformation, which can be monitored by geodetic techniques, such as GPS and InSAR. These geodetic signals are commonly analyzed through geodetic models in order to constrain the shape of, and the pressure in, magma plumbing systems. These models, however, suffer critical limitations: (1) the modelled magma conduit shapes cannot be compared with the real conduits, so the geodetic models cannot be tested nor validated; (2) the modelled conduits only exhibit shapes that are too simplistic; (3) most geodetic models only account for elasticity of the host rock, whereas substantial plastic deformation is known to occur. To overcome these limitations, one needs to use a physical system, in which (1) both surface deformation and the shape of, and pressure in, the underlying conduit are known, and (2) the mechanical properties of the host material are controlled and well known. In this contribution, we present novel quantitative laboratory results of shallow magma emplacement. Fine-grained silica flour represents the brittle crust, and low viscosity vegetable oil is an analogue for the magma. The melting temperature of the oil is 31°C; the oil solidifies in the models after the end of the experiments. At the time of injection the oil temperature is 50°C. The oil is pumped from a reservoir using a volumetric pump into the silica flour through a circular inlet at the bottom of a 40x40 cm square box. The silica flour is cohesive, such that oil intrudes it by fracturing it, and produces typical sheet intrusions (dykes, cone sheets, etc.). During oil intrusion, the model surface deforms, mostly by doming. These movements are measured by an advanced photogrammetry method, which uses 4 synchronized fixed cameras that periodically image the surface of the model from different angles. We apply particle tracking method to compute the 3D ground deformation pattern through time. After solidification of the oil, the intrusion can be excavated and photographed from several angles to compute its 3D shape with the same photogrammetry method. Then, the surface deformation pattern can be directly compared with the shape of underlying intrusion. This quantitative dataset is essential to quantitatively test and validate classical volcano geodetic models.

Færøvik Johannessen, Rikke; Galland, Olivier; Mair, Karen

2014-05-01

287

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

288

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

289

Seismic structure of Taal volcano  

Microsoft Academic Search

In order to investigate seismicity and tectonic structure under Taal volcano, Philippines, a temporary seismic array consisting of 8 stations was deployed in this area since March 2008. As a pioneer seismic study in this area, our first goal is to build a robust 1-D velocity model using local earthquakes. In the mean time, we also apply ambient noise cross-correlation

Shuei-Huei You; Yuancheng Gung; Konstantinos I. Konstantinou; Cheng-Horng Lin; Emmy T. Y. Chang

2010-01-01

290

Infrared science of Hawaiian volcanoes  

USGS Publications Warehouse

Aerial infrared-sensor surveys of Kilauea volcano have depicted the areal extent and the relative intensity of abnormal thermal features in the caldera area of the volcano and along its associated rift zones. Many of these anomalies show correlation with visible steaming and reflect convective transfer of heat to the surface from subterranean sources. Structural details of the volcano, some not evident from surface observation, are also delineated by their thermal abnormalities. Several changes were observed in the patterns of infrared emission during the period of study; two such changes show correlation in location with subsequent eruptions, but the cause-and-effect relationship is uncertain. Thermal anomalies were also observed on the southwest flank of Mauna Loa; images of other volcanoes on the island of Hawaii, and of Haleakala on the island of Maui, revealed no thermal abnormalities. Approximately 25 large springs is- suing into the ocean around the periphery of Hawaii have been detected. Infrared emission varies widely with surface texture and composition, suggesting that similar observations may have value for estimating surface conditions on the moon or planets.

Fischer, William A.; Moxham, R.M.; Polcyn, R.C.; Landis, G.H.

1964-01-01

291

Large landslides from oceanic volcanoes  

Microsoft Academic Search

GLORIA sidescan sonar surveys have shown that large landslides are ubiquitous around the submarine flanks of Hawaiian volcanoes, and GLORIA has also revealed large landslides offshore from Tristan da Cunha and El Hierro. On both of the latter islands, steep flanks formerly attributed to tilting or marine erosion have been reinterpreted as landslide headwalls mantled by younger lava flows. Large

Robin T. Holcomb; Roger C. Searle

1991-01-01

292

What Happened to Our Volcano?  

ERIC Educational Resources Information Center

In this article, the author presents an investigative approach to "understanding Earth changes." The author states that 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. Here, their geology unit helped them understand and…

Mangiante, Elaine Silva

2006-01-01

293

Kanaga Volcano, Aleutian Islands, Alaska  

NSDL National Science Digital Library

These images of the Kanaga Volcano show the symmetrical cone which is characteristic of stratovolcanoes. It is also possible to see how the current volcanic edifice has grown inside an older caldera, the remains of ancient Mount Kanaton. References and links to related sites are included.

294

Mount Rainier, a decade volcano  

SciTech Connect

Mount Rainier, recently designated as a decade volcano, is a 14,410 foot landmark which towers over the heavily populated southern Puget Sound Lowland of Washington State. It last erupted in the mid-1800's and is an obvious threat to this area, yet Rainier has received little detailed study. Previous work has divided Rainier into two distinct pre-glacial eruptive episodes and one post-glacial eruptive episode. In a pilot project, the authors analyzed 253 well-located samples from the volcano for 27 major and trace elements. Their objective is to test the value of chemical compositions as a tool in mapping the stratigraphy and understanding the eruptive history of the volcano which they regard as prerequisite to determining the petrogenesis and potential hazard of the volcano. The preliminary data demonstrates that variation between flows is significantly greater than intra-flow variation -- a necessary condition for stratigraphic use. Numerous flows or groups of flows can be distinguished chemically. It is also apparent from the small variation in Zr abundances and considerable variation in such ratios as Ba/Nb that fractional crystallization plays a subordinate role to some form of mixing process in the origin of the Mount Rainier lavas.

Kuehn, S.C.; Hooper, P.R. (Washington State Univ., Pullman, WA (United States). Dept. of Geology); Eggers, A.E. (Univ. of Puget Sound, Tacoma, WA (United States). Dept. of Geology)

1993-04-01

295

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.

Steven N. Ward

296

Alaska Volcano Observatory at 20  

Microsoft Academic Search

The Alaska Volcano Observatory (AVO) was established in 1988 in the wake of the 1986 Augustine eruption through a congressional earmark. Even within the volcanological community, there was skepticism about AVO. Populations directly at risk in Alaska were small compared to Cascadia, and the logistical costs of installing and maintaining monitoring equipment were much higher. Questions were raised concerning the

J. C. Eichelberger

2008-01-01

297

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

298

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

299

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

300

Potential hazards from future eruptions of Mount St. Helens Volcano, Washington  

USGS Publications Warehouse

Mount St. Helens has been more active and more explosive during the last 4,500 years than any other volcano in the conterminous United States. Eruptions of that period repeatedly formed domes, large volumes of pumice, hot pyroclastic flows, and, during the last 2,500 years, lava flows. Some of this activity resulted in mudflows that extended tens of kilometers down the floors of valleys that head at the volcano. This report describes the nature of the phenomena and their threat to people and property; the accompanying maps show areas likely to be affected by future eruptions of Mount St. Helens. Explosive eruptions that produce large volumes of pumice affect large areas because winds can carry the lightweight material hundreds of kilometers from the volcano. Because of prevailing winds, the 180-degree sector east of the volcano will be affected most often and most severely by future eruptions of this kind. However, the pumice from any one eruption will fall in only a small part of that sector. Pyroclastic flows and mudflows also can affect areas far from the volcano, but the areas they affect are smaller because they follow valleys. Mudflows and possibly pyroclastic flows moving rapidly down Swift and Pine Creeks could displace water in Swift Reservoir, which could cause disastrous floods farther downvalley.

Crandell, Dwight Raymond; Mullineaux, Donal Ray

1978-01-01

301

Damavand volcano spreading detected by advanced InSAR time series  

NASA Astrophysics Data System (ADS)

Unlike the ordinary mountains, volcanoes are mostly formed rapidly. As a result many of them are subject to gradual spreading and sometimes massive flank failures. This spreading specially in case of being directional can be assessed as a precursor for the future flank collapse. Herein using an advanced InSAR time series approach and consuming a data set of ENVISAT radar images spanning period of 2003 till 2009 we obtain spatiotemporal deformation field over Damavand volcano, in north Iran. This volcano that is located in the north-east of the capital city Tehran with over 13 million inhabitants, exhibit continuously fumarolic activity and considered as potentially active volcano. The obtained deformation time series shows sort of gradual spreading in the direction of the regional stressing access which emphasizes that spreading and probable failure can happen even without any associated magmatic activity. In this work using InSAR time series, geological and metrological data we investigate the presence of spreading partitioning regarding the geological units and also we assess the influence of the rain fall on the occasional changes in the rate of spreading. Finally we underline the importance of continuous monitoring (such as the approach we employed here for InSAR time series generation) for timely forecasting future flank failure associated to Damavand volcano, which might be another significant hazard for Tehran city, regardless of magmatic activity.

Shirzaei, Manoochehr; Walter, Thomas

2010-05-01

302

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

303

Continuous monitoring of Hawaiian volcanoes using thermal cameras  

NASA Astrophysics Data System (ADS)

Thermal cameras are becoming more common at volcanoes around the world, and have become a powerful tool for observing volcanic activity. Fixed, continuously recording thermal cameras have been installed by the Hawaiian Volcano Observatory in the last two years at four locations on Kilauea Volcano to better monitor its two ongoing eruptions. The summit eruption, which began in March 2008, hosts an active lava lake deep within a fume-filled vent crater. A thermal camera perched on the rim of Halema`uma`u Crater, acquiring an image every five seconds, has now captured about two years of sustained lava lake activity, including frequent lava level fluctuations, small explosions , and several draining events. This thermal camera has been able to "see" through the thick fume in the crater, providing truly 24/7 monitoring that would not be possible with normal webcams. The east rift zone eruption, which began in 1983, has chiefly consisted of effusion through lava tubes onto the surface, but over the past two years has been interrupted by an intrusion, lava fountaining, crater collapse, and perched lava lake growth and draining. The three thermal cameras on the east rift zone, all on Pu`u `O`o cone and acquiring an image every several minutes, have captured many of these changes and are providing an improved means for alerting observatory staff of new activity. Plans are underway to install a thermal camera at the summit of Mauna Loa to monitor and alert to any future changes there. Thermal cameras are more difficult to install, and image acquisition and processing are more complicated than with visual webcams. Our system is based in part on the successful thermal camera installations by Italian volcanologists on Stromboli and Vulcano. Equipment includes custom enclosures with IR transmissive windows, power, and telemetry. Data acquisition is based on ActiveX controls, and data management is done using automated Matlab scripts. Higher-level data processing, also done with Matlab, includes automated measurements of lava lake level and surface crust velocity, tracking temperatures and hot areas in real-time, and alerts which notify users of notable temperature increases via text messaging. Lastly, real-time image and processed data display, which is vital for effective use of the images at the observatory, is done through a custom Web-based environment . Near real-time webcam images are displayed for the public at hvo.wr.usgs.gov/cams. Thermal cameras are costly, but have proven to be an extremely effective monitoring and research tool at the Hawaiian Volcano Observatory.

Patrick, M. R.; Orr, T. R.; Antolik, L.; Lee, R.; Kamibayashi, K.

2012-12-01

304

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....

305

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....

306

Review of the United States Geological Survey Volcano Hazards Program  

E-print Network

Review of the United States Geological Survey Volcano Hazards Program Authors and Review Panel.................................................................................................................. 6 1.1 The Volcano Hazards Program Mission and Significance......................................................................................................... 12 3.1 Volcano Hazard Assessments

Torgersen, Christian

307

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

308

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.

309

USGS Photo glossary of volcano terms  

NSDL National Science Digital Library

This website, part of the USGS Volcano Hazards Program, can help users distinguish among various types of volcanoes, vents, eruption types, and ejected material. The site features an extensive list of volcanic vocabulary, along with photographs and text for each entry. Users can also check out the latest U.S. volcanic activity reported by the USGS volcano observatories, which are linked to the page.

USGS

310

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

311

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

E-print Network

07406, doi:10.1029/2009JB007022. 1. Introduction [2] The study of volcanoes continues to benefit fromClick Here for Full Article Volcano monitoring using GPS: Developing data analysis strategies based on the June 2007 Klauea Volcano intrusion and eruption Kristine M. Larson,1 Michael Poland,2 and Asta Miklius2

Larson, Kristine

312

The volcano-magnetic effect  

Microsoft Academic Search

Summary  A geometrically simple volcano is considered, havig a spherical magma chamber of 2.5 km radius centred at 10 km depth. The\\u000a Curie point isotherm is assumed to be a plane at 20 km depth, except for the spherical volume which is also non-magnetic.\\u000a The stress pattern in the vicinity of the spherical chamber, due to regional stress of sufficient intensity

Frank D. Stacey; Kenneth G. Barr; Geoffrey R. Robson

1965-01-01

313

Seismic structure of Taal volcano  

NASA Astrophysics Data System (ADS)

In order to investigate seismicity and tectonic structure under Taal volcano, Philippines, a temporary seismic array consisting of 8 stations was deployed in this area since March 2008. As a pioneer seismic study in this area, our first goal is to build a robust 1-D velocity model using local earthquakes. In the mean time, we also apply ambient noise cross-correlation technique to the continuous records, aiming to search for the potential volcanic structure perturbations. While we were trying to retrieve Empirical Green's functions from cross-correlation functions (CCF) of ambient noise, unexpected linear drifting of clock time are clearly identified by the gradual shifting of symmetric center of daily CCFs. The clock errors have been further confirmed by comparing earthquake signals from teleseismic events. The errors are corrected before further data processing. Over 1100 local events are recorded in the duration from March 2008 to November 2008. Phase pickings from about 450 events are used to invert for event locations and 1-D velocity model by using the standard packages HYPO71 and VELEST. The obtained 1-D velocity model of Taal volcano is lower than the global average (AK135) at the depths less than 10 km, and most events (~90%) are also located at this shallow depth range. Two groups of seismicity are noticed, with the major one clustered under the western shore of Taal lake ranging, and the other spread from Main Crater Lake to the eastern of Taal volcano complex.

You, Shuei-Huei; Gung, Yuancheng; Konstantinou, Konstantinos I.; Lin, Cheng-Horng; Chang, Emmy T. Y.

2010-05-01

314

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

315

Surface deformation analysis of the Mauna Loa and Kilauea volcanoes, Hawaii , revealed by InSAR measurements  

NASA Astrophysics Data System (ADS)

The Big Island of Hawaii is home to three volcanoes that have historically erupted. Hual?lai, on the east side of the island, Mauna Loa, the largest volcano on the planet which has erupted 39 times since 1832 (most recently in 1984) and Kilauea, which has been in a state of continuous eruption since 1983 from vents on the volcano's east rift zone. Deformation at Kilauea is characterized by summit and rift zone displacements related to magmatic activity and seaward motion of the south flank caused by slip along a basal decollement. In this work we investigate the deformation affecting the Mauna Loa and Kilauea volcanoes, Hawaii , by exploiting the advanced Interferometric Synthetic Aperture Radar (InSAR) technique referred to as Small BAseline Subset (SBAS) algorithm. In particular, we present time series of line-of-sight (LOS) displacements derived from the SAR data acquired by the ASAR instrument, on board the ENVISAT satellite, from the ascending (track 93, frame 387) and descending (track 429, frame 3213) orbits over a time period between 2003 and 2008. For each coherent pixel of the radar images we compute time-dependent surface displacements as well as the average LOS deformation velocity. We also benefit from the use of the multi-orbit (ascending and descending) data which permit us to discriminate the vertical and east-west components of the revealed displacements. The retrieved InSAR measurements are also favourably compared to the continuous GPS data available in the area in order to asses the quality of the SBAS-InSAR products. The presented results show the complex and articulated deformation behavior of the investigated volcanoes; moreover, the possibility to invert the retrieved DInSAR products, in order to model both deep geological structures and magmatic sources, represents a relevant issue for the comprehension of the volcanoes dynamics.

Casu, F.; Poland, M.; Solaro, G.; Tizzani, P.; Miklius, A.; Sansosti, E.; Lanari, R.

2009-04-01

316

Thematic mapper studies of Andean volcanoes  

NASA Technical Reports Server (NTRS)

The primary objective was to identify all the active volcanoes in the Andean region of Bolivia. Morphological features of the Tata Sabaya volcano, Bolivia, were studied with the thematic mapper. Details include marginal levees on lava and pyroclastic flows, and summit crater structure. Valley glacier moraine deposits, not easily identified on the multispectral band scanner, were also unambiguous, and provide useful marker horizons on large volcanic edifices which were built up in preglacial times but which were active subsequently. With such high resolution imagery, it is not only possible to identify potentially active volcanoes, but also to use standard photogeological interpretation to outline the history of individual volcanoes.

Francis, P. W.

1986-01-01

317

Cascade Range Volcanoes: North to South  

NSDL National Science Digital Library

This page lists Cascades Range volcanoes of British Columbia, Washington State, Oregon, and California. The user can click on the volcano name to get information on the volcano and its vicinity including Current Activity; Background and Information; Current Hazards Report; Visit a Volcano; Maps, Graphics, and Images; Items of Interest; and Useful Links. The volcanoes include: Garibaldi Lake Volcano, Meager Mountain, and Mount Garibaldi in British Columbia; Mount Baker, Glacier Peak, Mount Rainier, Mount St. Helens, and Mount Adams in Washington State: Mount Hood, Mount Jefferson, Three-Fingered Jack, Mount Washington, Belknap Shield Volcano, Three Sisters (North, Middle, South), Broken Top, Mount Bachelor, Pilot Butte, Lava Butte, Newberry Caldera, Diamond Peak, Mount Bailey, Mount Thielsen, Crater Lake, Mount Mazama, Wizard Island, and Mount McLoughlin in Oregon:, and Lava Beds, Medicine Lake Volcano, Glass Mountain (Medicine Lake, California), Black Butte, Mount Shasta, and Lassen Peak in California. Links are provided to more general pages on volcanoes in the three states and in Canada.

318

From: Volcano Watch, September 26, 1997 Volcano Watch, a weekly feature written by scientists at the USGS Hawaiian Volcano Observatory, is  

E-print Network

From: Volcano Watch, September 26, 1997 Volcano Watch, a weekly feature written by scientists at the USGS Hawaiian Volcano Observatory, is posted on the HVO Web site (http zone of Mauna Loa Volcano in historic time. The 1919 Alika eruption was the most voluminous historical

319

Rockfalls at Augustine Volcano, Alaska: 2003-2006  

NASA Astrophysics Data System (ADS)

Rockfalls, avalanches and landslides have been frequently recorded in seismic data at Augustine Volcano for many years. Typical years such as 2003 or 2004 had several dozen such events that were strong enough to trigger the automatic event detection system. Typical events lasted about 30 sec, had frequencies >6 Hz, and were strongest on summit stations, suggesting that they were rockfalls from the steep summit dome into the adjacent moat area. In 2005 both the rate and the occurrence pattern changed. Rockfall activity began in April 2006 and peaked in May and June, then continued through the fall and early winter. Overall there were more than 340 rockfalls in 2005, with both small and large events occurring. The 2005 rockfall activity increased at nearly the same time as earthquake activity and heating of the ground, suggesting that higher temperatures and steaming contributed to mechanical instabilities of the surface dome rocks. We examined relative amplitudes at station pairs and frequency contents to determine relative locations of the rockfalls by assuming that both higher amplitudes and higher frequencies are associated with events closer to a given station. When a low-light camera was installed at Augustine in January 2006 we were able to confirm these relations because there was a clear correlation between rockfalls, debris flows, and pyroclasic flows to the east (towards the camera) and high amplitudes and frequencies at east station AUE. Other events had high amplitudes and higher frequencies at west station AUW and no material was seen moving to the east. Still other events moved to the north and amplitudes were nearly the same at AUE and AUW. The systematic patterns in amplitude and frequency, verified by data from the low-light camera, make it possible to estimate mass flow in various directions using seismic data. Energy estimates of the rockfalls made from video images can be compared with energy estimates from magnitude-energy equations. The observer stations AUE and AUW show shifts in the frequency depending on whether the rockfalls are moving toward or away from them. Estimates of the seismic wave speeds from the rockfalls can be estimated using the Doppler equation, since the rockfalls are a moving frequency source. Also in progress is a program to estimate mass flow around the flanks of the volcano, using the amplitude ratios from stations around the volcano. The results from this work can be compared with geologic maps of deposits from the 2006 eruptions. The high rate of rockfalls in 2005 was also a new class of precursory signal that may be incorporated into long-term monitoring strategies at Augustine and elsewhere.

Deroin, N.; McNutt, S. R.; Reyes, C.; Sentman, D.

2007-12-01

320

Geophysical characteristics of the hydrothermal systems of Kilauea volcano, Hawaii  

SciTech Connect

Clues to the structure of Kilauea volcano can be obtained from spatial studies of gravity, magnetic, and seismic velocity variations. The rift zones and summit are underlain by dense, magnetic, and seismic velocity variations. The rift zones and summit are underlain by dense, magnetic, high P-wave-velocity rocks at depths of about 2 km less. The gravity and seismic velocity studies indicate that the rift structures are broad, extending farther to the north than to the south of the surface features. The magnetic data allow separation into a narrow, highly-magnetized, shallow zone and broad, flanking, magnetic lows. The patterns of gravity, magnetic variations, and seismicity document the southward migration of the upper east rift zone. Regional, hydrologic features of Kilauea can be determined from resistivity and self-potential studies. High-level groundwater exists beneath Kilauea summit to elevations of +800 m within a triangular area bounded by the west edge of the upper southwest rift zone, the east edge of the upper east rift zone, and the Koa'e fault system. High-level groundwater is present within the east rift zone beyond the triangular summit area. Self-potential mapping shows that areas of local heat produce local fluid circulation in the unconfined aquifer (water table). Shallow seismicity and surface deformation indicate that magma is intruding and that fractures are forming beneath the rift zones and summit area. Heat flows of 370--820 mW/m[sup 2] are calculated from deep wells within the lower east rift zone. The estimated heat input rate for Kilauea of 9 gigawatts (GW) is at least 25 times higher than the conductive heat loss as estimated from the heat flow in wells extrapolated over the area of the summit caldera and rift zones. 115 refs., 13 figs., 1 tab.

Kauahikaua, J. (Hawaiian Volcano Observatory, Hawaii National Park, HI (United States))

1993-08-01

321

Alaska Volcano Observatory at 20  

NASA Astrophysics Data System (ADS)

The Alaska Volcano Observatory (AVO) was established in 1988 in the wake of the 1986 Augustine eruption through a congressional earmark. Even within the volcanological community, there was skepticism about AVO. Populations directly at risk in Alaska were small compared to Cascadia, and the logistical costs of installing and maintaining monitoring equipment were much higher. Questions were raised concerning the technical feasibility of keeping seismic stations operating through the long, dark, stormy Alaska winters. Some argued that AVO should simply cover Augustine with instruments and wait for the next eruption there, expected in the mid 90s (but delayed until 2006), rather than stretching to instrument as many volcanoes as possible. No sooner was AVO in place than Redoubt erupted and a fully loaded passenger 747 strayed into the eruption cloud between Anchorage and Fairbanks, causing a powerless glide to within a minute of impact before the pilot could restart two engines and limp into Anchorage. This event forcefully made the case that volcano hazard mitigation is not just about people and infrastructure on the ground, and is particularly important in the heavily traveled North Pacific where options for flight diversion are few. In 1996, new funding became available through an FAA earmark to aggressively extend volcano monitoring far into the Aleutian Islands with both ground-based networks and round-the-clock satellite monitoring. Beyond the Aleutians, AVO developed a monitoring partnership with Russians volcanologists at the Institute of Volcanology and Seismology in Petropavlovsk-Kamchatsky. The need to work together internationally on subduction phenomena that span borders led to formation of the Japan-Kamchatka-Alaska Subduction Processes (JKASP) consortium. JKASP meets approximately biennially in Sapporo, Petropavlovsk, and Fairbanks. In turn, these meetings and support from NSF and the Russian Academy of Sciences led to new international education and research opportunities for Russian and American students. AVO was a three-way partnership of the federal and state geological surveys and the state university from the start. This was not a flowering of ecumenism but was rather at the insistence of the Alaska congressional delegation. Such shared enterprises are not managerially convenient, but they do bring a diversity of roles, thinking, and expertise that would not otherwise be possible. Through AVO, the USGS performs its federally mandated role in natural hazard mitigation and draws on expertise available from its network of volcano observatories. The Alaska Division of Geological and Geophysical Surveys performs a similar role at the state level and, in the tradition of state surveys, provides important public communications, state data base, and mapping functions. The University of Alaska Fairbanks brought seismological, remote sensing, geodetic, petrological, and physical volcanological expertise, and uniquely within US academia was able to engage students directly in volcano observatory activities. Although this "model" cannot be adopted in total elsewhere, it has served to point the USGS Volcano Hazards Program in a direction of greater openness and inclusiveness.

Eichelberger, J. C.

2008-12-01

322

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

323

Ambient noise recovery of surface wave Green's functions: Application at Hawaiian volcanoes  

NASA Astrophysics Data System (ADS)

Hazard assessment of Hawaiian volcanoes critically depends on the understanding of their evolution and dynamics. Previous studies suggest that ambient seismic noise analyses may aid in volcano research and monitoring. Green’s functions derived from ambient noise have been used to perform tomography of the shallow structures (< 5 km depth) at other volcanoes [1, 2]. Moreover, these Green’s functions have been used to monitor very small shallow velocity perturbations prior to eruptions [3]. This promising technique, however, has not yet been applied to any Hawaiian volcano. Here, we examine data from the USGS Hawaii Volcano Observatory short-period seismic network to assess the potential of such ambient noise analyses to constrain spatial velocity heterogeneity and temporal perturbations at Kilauea and Mauna Loa volcanoes. We have obtained continuous seismic data from May 2007 through April 2008. This time period includes two important volcanic events. 1) The Father’s Day dike intrusion into Kilauea’s east rift zone that occurred on June 17, 2007. 2) The Kilauea summit eruption of March 19, 2008 and the high summit activity (that includes high tremor levels) that has since followed. The success of any noise study of temporal velocity perturbations will depend critically on whether stable Green’s functions can be recovered. However, for applications at Hawaii it is possible that during some time frames high volcanic tremor levels may distort ambient noise records and hence limit the results. Using the technical approach described in [2], we plan to examine numerous station pairs to determine the times when stable Green’s functions can be extracted from noise (0.1-1 Hz) that is typically made up of Rayleigh waves created by wind-generated ocean waves. As a first step, we investigate the period around the 2007 dike intrusion to evaluate the applicability of noise interferometry to Kilauea volcano. [1] Brenguier, F., N. M. Shapiro, M. Campillo, A. Nercessian, and V. Ferrazzini, 3-D surface wave tomography of the Piton de la Fournaise volcano using seismic noise observations, Geophys. Res. Lett., 34, doi:10.1029/2006GL028586, 2007. [2] Masterlark, T., M. Haney, H. Dickinson, T. Fournier, and C. Searcy, Rheologic and structural controls on the deformation of Okmok volcano, Alaska: FEMs, InSAR, and ambient noise tomography, J. Geophys. Res., 115, B02409, 2010. [3] Brenguier, F. N. M. Shapiro, M. Campillo, V. Ferrazzini, Z. Duputel, O. Coutant, and A. Nercessian, Towards forecasting volcanic eruptions using seismic noise, Nature Geosci., 1, 126-130, 2008.

Ballmer, S.; Wolfe, C. J.; Okubo, P.; Haney, M. M.; Thurber, C. H.

2010-12-01

324

Dike injection and magma mixing in Kenya rift volcanoes  

NASA Astrophysics Data System (ADS)

A nexus of volcanoes in the rift graben at approximately the latitude of Nairobi consist of central vent trachyte, phonolite, and peralkaline rhyolite and cinder cone and fissure-fed flows of basalt to benmoreite. The volcanoes are referred to as the Central Kenya Peralkaline Province (CKPP, Macdonald and Scaillet, 2006, Lithos 91, 59-73) and formed by a combination of processes including fractional crystallization, magma mixing, and volatile transport (Ren et al., 2006, Lithos 91, 109-124; Macdonald et al., 2008, JPet 49, 1515-1547). This presentation focuses on magma mixing for trachytes and phonolites for Suswa rocks, which are the southernmost part of the CKPP. We also explore the contribution of magma process studies to the interpretation of recent geodetic data, which indicate inflation/deflation of up to 21 cm for Kenyan volcanoes from 1997 to present (Biggs et al., 2009, Geology, in press). Incontrovertible evidence for magma mixing is found in field evidence, where a basaltic trachyandesite ash horizon is found interbedded with syncaldera trachyte (Skilling, 1993, J. Geol. Society London 150, 885-896), hand-specimen and thin-section petrography, and disequilibrium mineral chemistry. Precaldera lavas contain a homogeneous group of anorthoclase crystals with An content 6% or less. Syncaldera samples contain this same group and two other populations: polysynthetic twinned labradorite and andesine and anorthoclase with An content of 17%. Textures for all three groups indicate disequilibrium. Postcaldera flows contain the high and low An anorthoclase populations but lack the polysynthetic twinned labradorite and andesine. These observations suggest a model of injection of mafic magmas via diking into shallow trachtytic magma systems. Recent geodetic studies of dike injection and subsequent seismic/volcanic activity in both Ethiopia and Lengai point to the ongoing importance of these processes to rift evolution in East Africa.

Anthony, E. Y.; Espejel, V.; Biggs, J.

2009-12-01

325

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

326

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

327

On Relations between Current Global Volcano Databases  

Microsoft Academic Search

The Smithsonian's Volcano Reference File (VRF), the database that underlies Volcanoes of the World and This Dynamic Planet, is the premier source for the ``what, when, where, and how big?'' of Holocene and historical eruptions. VOGRIPA (Volcanic Global Risk Identification and Analysis) will catalogue details of large eruptions, including specific phenomena and their impacts. CCDB (Collapse Caldera Database) also considers

C. G. Newhall; L. Siebert; S. Sparks

2009-01-01

328

Automating the hunt for volcanoes on Venus  

Microsoft Academic Search

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

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

1994-01-01

329

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

330

Endogenous growth of persistently active volcanoes  

Microsoft Academic Search

LAVA lakes and active strombolian vents have persisted at some volcanoes for periods exceeding the historic record. They liberate prodigious amounts of volatiles and thermal energy but erupt little lava, a paradox that raises questions about how volcanoes grow. Although long-lasting surface manifestations can be sustained by convective exchange of magma with deeper reservoirs, residence times of magmas beneath several

Peter Francis; Clive Oppenheimer; David Stevenson

1993-01-01

331

Orographic Flow over an Active Volcano  

NASA Astrophysics Data System (ADS)

Orographic flows over and around an isolated volcano are studied through a series of numerical model experiments. The volcano top has a heated surface, so can be thought of as "active" but not erupting. A series of simulations with different atmospheric conditions and using both idealised and realistic configurations of the Weather Research and Forecast (WRF) model have been carried out. The study is based on the Soufriere Hills volcano, located on the island of Montserrat in the Caribbean. This is a dome-building volcano, leading to a sharp increase in the surface skin temperature at the top of the volcano - up to tens of degrees higher than ambient values. The majority of the simulations use an idealised topography, in order for the results to have general applicability to similar-sized volcanoes located in the tropics. The model is initialised with idealised atmospheric soundings, representative of qualitatively different atmospheric conditions from the rainy season in the tropics. The simulations reveal significant changes to the orographic flow response, depending upon the size of the temperature anomaly and the atmospheric conditions. The flow regime and characteristic features such as gravity waves, orographic clouds and orographic rainfall patterns can all be qualitatively changed by the surface heating anomaly. Orographic rainfall over the volcano can be significantly enhanced with increased temperature anomaly. The implications for the eruptive behaviour of the volcano and resulting secondary volcanic hazards will also be discussed.

Poulidis, Alexandros-Panagiotis; Renfrew, Ian; Matthews, Adrian

2014-05-01

332

Thermal surveillance of active volcanoes. [infrared scanner recordings of thermal anomalies of Mt. Baker volcano  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. By the end of 1973, aerial infrared scanner traverses for thermal anomaly recordings of all Cascade Range volcanoes were essentially completed. Amplitude level slices of the Mount Baker anomalies were completed and compiled at a scale of 1:24,000, thus producing, for the first time, an accurate map of the distribution and intensity of thermal activity on Mount Baker. The major thermal activity is concentrated within the crater south of the main summit and although it is characterized by intensive solfataric activity and warm ground, it is largely subglacial, causing the development of sizable glacier perforation features. The outgoing radiative flux from the east breach anomalies is sufficient to account for the volume of ice melted to form the glacier perforations. DCP station 6251 has been monitoring a thermally anomalous area on the north slope of Mount Baker. The present thermal activity of Mount Baker accounts for continuing hydrothermal alteration in the crater south of the main summit and recurrent debris avalanches from Sherman Peak on its south rim. The infrared anomalies mapped as part of the experiment SR 251 are considered the basic evidence of the subglacial heating which was the probable triggering mechanism of an avalanche down Boulder Glacier on August 20-21, 1973.

Friedman, J. D. (principal investigator)

1974-01-01

333

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

334

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

335

Isotopic approach to understanding the groundwater flow system within an andesitic stratovolcano in a temperate humid region: case study of Ontake volcano, central Japan  

NASA Astrophysics Data System (ADS)

We used isotope tracer methods to clarify the groundwater flow system within Mt. Ontake: a stratovolcano consisted of andesite lava and pyroclastic rock, located within a temperate humid region. Precipitation was collected monthly at 11 sites on the south, east, north, and west slopes of the volcano for a period of 26 months. The weighted mean delta-value in precipitation show a clear decrease with increasing elevation (altitude effect) on all slopes and is relatively low on the leeward slope (rain-shadowing effect). The springs collected over the entire area of the volcano show ? values that are controlled by the altitude effect and the rain-shadowing effect on precipitation. The average recharge elevation of the individual springs was calculated from their ?18O values and the equation of the altitude effect of groundwater for corresponding slope. The average recharge elevation and tritium concentration in springs indicate that the large-scale groundwater flow systems (vertical drop: ca. 800m) with a relatively long residence time are maintained along the lava flow in the younger volcano north zone, whereas a relatively small-scale groundwater flow systems (vertical drop: ca. 400m) distribute across a wide range of elevation in the younger volcano south zone. In older volcano zone at the foot of the volcano body, it is inferred that local groundwater flow systems (vertical drop: less than 200m) dominate and that these flow systems are not connected to those in the younger volcano zone. Consequently, the scale of the groundwater flow system decreases with increasing age of the volcano body. This contraction of the flow system with time might reflect the progressive erosion of the volcano body, especially within the younger volcano zone.

Asai, K.; Satake, H.; Tsujimura, M.

2007-12-01

336

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

337

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

338

Volcano-earthquake interaction at Mauna Loa volcano, Hawaii  

NASA Astrophysics Data System (ADS)

The activity at Mauna Loa volcano, Hawaii, is characterized by eruptive fissures that propagate 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 the hypothesis that the events are interconnected in time and space. Earthquakes in the Kaoiki area occur in sequence with eruptions from the NERZ, and earthquakes in the Kona and Hilea areas occur in sequence with eruptions from the SWRZ. Using three-dimensional numerical models, we demonstrate that elastic stress transfer can explain the observed volcano-earthquake interaction. We examine stress changes due to typical intrusions and earthquakes. We find that intrusions change the Coulomb failure stress along the decollement fault so that NERZ intrusions encourage Kaoiki earthquakes and SWRZ intrusions encourage Kona and Hilea earthquakes. On the other hand, earthquakes decompress the magma chamber and unclamp part of the Mauna Loa rift zone, i.e., Kaoiki earthquakes encourage NERZ intrusions, whereas Kona and Hilea earthquakes encourage SWRZ intrusions. We discuss how changes of the static stress field affect the occurrence of earthquakes as well as the occurrence, location, and volume of dikes and of associated eruptions and also the lava composition and fumarolic activity.

Walter, Thomas R.; Amelung, Falk

2006-05-01

339

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.

340

Studying temporal velocity changes with ambient seismic noise at Hawaiian volcanoes  

NASA Astrophysics Data System (ADS)

In order to understand the dynamics of volcanoes and to assess the associated hazards, the analysis of ambient seismic noise - a continuous passive source - has been used for both imaging and monitoring temporal changes in seismic velocity. Between pairs of seismic stations, surface wave Green's functions can be retrieved from the background ocean-generated noise being sensitive to the shallow subsurface. Such Green's functions allow the measurement of very small temporal perturbations in seismic velocity with a variety of applications. In particular, velocity decreases prior to some volcanic eruptions have been documented and motivate our present study. Here we perform ambient seismic noise interferometry to study temporal changes in seismic velocities within the shallow (<5km) subsurface of the Hawaiian volcanoes. Our study is the first to assess the potential for using ambient noise analyses as a tool for Hawaiian volcano monitoring. Five volcanoes comprise the island of Hawaii, of which two are active: Mauna Loa volcano, which last erupted in 1984, and Kilauea volcano, where the Pu'u'O'o-Kupaianaha eruption along the east rift zone has been ongoing since 1983. For our analysis, we use data from the USGS Hawaiian Volcano Observatory (HVO) seismic network from 05/2007 to 12/2009. Our study period includes the Father's Day dike intrusion into Kilauea's east rift zone in mid-June 2007 as well as increased summit activity commencing in late 2007 and leading to several minor explosions in early 2008. These volcanic events are of interest for the study of potential associated seismic velocity changes. However, we find that volcanic tremor complicates the measurement of velocity changes. Volcanic tremor is continuously present during most of our study period, and contaminates the recovered Green's functions for station pairs across the entire island. Initial results suggest that a careful quality assessment (i.e. visually inspecting the Green's functions and filtering to remove tremor) diminishes the effects of tremor and allows for resolution of relative velocity changes on the order of less than 1%. The observed velocity changes will be compared with known volcanic activity in space and time, and interpreted in view of underlying processes.

Ballmer, S.; Wolfe, C. J.; Okubo, P. G.; Haney, M. M.; Thurber, C. H.

2012-04-01

341

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

342

Physical volcanology of the submarine Mariana and Volcano Arcs  

Microsoft Academic Search

Narrow-beam maps, selected dredge samplings, and surveys of the Mariana and Volcano Arcs identify 42 submarine volcanos. Observed activity and sample characteristics indicate 22 of these to be active or dormant. Edifices in the Volcano Arc are larger than most of the Mariana Arc edifices, more irregularly shaped with numerous subsidiary cones, and regularly spaced at 50–70 km. Volcanos in

Sherman H. Bloomer; Robert J. Stern; N. Christian Smoot

1989-01-01

343

Density Imaging of Volcanoes with Atmospheric Muons using GRPCs  

E-print Network

Density Imaging of Volcanoes with Atmospheric Muons using GRPCs Cristina Cârloganu Clermont of volcanoes with high-resolution tracking detectors. By exploiting Glass Resistive Plate Chambers (GRPCs of Volcanoes with Atmospheric Muons Cristina Cârloganu 1. Puy de Dôme as a reference site for volcano imaging

Paris-Sud XI, Université de

344

The deep structure of Axial Volcano Michael West  

E-print Network

The deep structure of Axial Volcano Michael West Thesis defense, June 4, 2001 #12;Motivation What Motivation Hekla Volcano, Iceland Kilauea Volcano, Hawaii #12;Juan de Fuca Ridge / Cobb-Eickelberg Chain Cobb-Eickleberg chain Axial Volcano Brown Bear Blanco F.Z. Vanceseg. Coaxial Cobb Brown Bear Axial Caldera #12;Axial

West, Michael

345

Preliminary Volcano-Hazard Assessment for the Tanaga Volcanic Cluster, Tanaga Island, Alaska  

USGS Publications Warehouse

Summary of Volcano Hazards at Tanaga Volcanic Cluster The Tanaga volcanic cluster lies on the northwest part of Tanaga Island, about 100 kilometers west of Adak, Alaska, and 2,025 kilometers southwest of Anchorage, Alaska. The cluster consists of three volcanoes-from west to east, they are Sajaka, Tanaga, and Takawangha. All three volcanoes have erupted in the last 1,000 years, producing lava flows and tephra (ash) deposits. A much less frequent, but potentially more hazardous phenomenon, is volcanic edifice collapse into the sea, which likely happens only on a timescale of every few thousands of years, at most. Parts of the volcanic bedrock near Takawangha have been altered by hydrothermal activity and are prone to slope failure, but such events only present a local hazard. Given the volcanic cluster's remote location, the primary hazard from the Tanaga volcanoes is airborne ash that could affect aircraft. In this report, we summarize the major volcanic hazards associated with the Tanaga volcanic cluster.

Coombs, Michelle L.; McGimsey, Robert G.; Browne, Brandon L.

2007-01-01

346

Overview of the 1990 1995 eruption at Unzen Volcano  

NASA Astrophysics Data System (ADS)

Following 198 years of dormancy, a small phreatic eruption started at the summit of Unzen Volcano (Mt. Fugen) in November 1990. A swarm of volcano-tectonic (VT) earthquakes had begun below the western flank of the volcano a year before this eruption, and isolated tremor occurred below the summit shortly before it. The focus of VT events had migrated eastward to the summit and became shallower. Following a period of phreatic activity, phreatomagmatic eruptions began in February 1991, became larger with time, and developed into a dacite dome eruption in May 1991 that lasted approximately 4 years. The emergence of the dome followed inflation, demagnetization and a swarm of high-frequency (HF) earthquakes in the crater area. After the dome appeared, activity of the VT earthquakes and the summit HF events was replaced largely by low-frequency (LF) earthquakes. Magma was discharged nearly continuously through the period of dome growth, and the rate decreased roughly with time. The lava dome grew in an unstable form on the shoulder of Mt. Fugen, with repeating partial collapses. The growth was exogenous when the lava effusion rate was high, and endogenous when low. A total of 13 lobes grew as a result of exogenous growth. Vigorous swarms of LF earthquakes occurred just prior to each lobe extrusion. Endogenous growth was accompanied by strong deformation of the crater floor and HF and LF earthquakes. By repeated exogenous and endogenous growth, a large dome was formed over the crater. Pyroclastic flows frequently descended to the northeast, east, and southeast, and their deposits extensively covered the eastern slope and flank of Mt. Fugen. Major pyroclastic flows took place when the lava effusion rate was high. Small vulcanian explosions were limited in the initial stage of dome growth. One of them occurred following collapse of the dome. The total volume of magma erupted was 2.1×10 8 m 3 (dense-rock-equivalent); about a half of this volume remained as a lava dome at the summit (1.2 km long, 0.8 km wide and 230-540 m high). The eruption finished with extrusion of a spine at the endogenous dome top. Several monitoring results convinced us that the eruption had come to an end: the minimal levels of both seismicity and rockfalls, no discharge of magma, the minimal SO 2 flux, and cessation of subsidence of the western flank of the volcano. The dome started slow deformation and cooling after the halt of magma effusion in February 1995.

Nakada, Setsuya; Shimizu, Hiroshi; Ohta, Kazuya

1999-04-01

347

Volcano-tectonic modelling of magma chambers, ring-faults, unrest, and eruptions in the Tianchi Volcano, China  

E-print Network

Volcano-tectonic modelling of magma chambers, ring-faults, unrest, and eruptions in the Tianchi Volcano, China Supervisor: Agust Gudmundsson Project Description: The Tianchi (Changbaishan) Volcano, located at the boundary between China and North Korea, is widely regarded as the most dangerous volcano

Sheldon, Nathan D.

348

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

349

Unzipping of the volcano arc, Japan  

USGS Publications Warehouse

A working hypothesis for the recent evolution of the southern Volcano Arc, Japan, is presented which calls upon a northward-progressing sundering of the arc in response to a northward-propagating back-arc basin extensional regime. This model appears to explain several localized and recent changes in the tectonic and magrnatic evolution of the Volcano Arc. Most important among these changes is the unusual composition of Iwo Jima volcanic rocks. This contrasts with normal arc tholeiites typical of the rest of the Izu-Volcano-Mariana and other primitive arcs in having alkaline tendencies, high concentrations of light REE and other incompatible elements, and relatively high silica contents. In spite of such fractionated characteristics, these lavas appear to be very early manifestations of a new volcanic and tectonic cycle in the southern Volcano Arc. These alkaline characteristics and indications of strong regional uplift are consistent with the recent development of an early stage of inter-arc basin rifting in the southern Volcano Arc. New bathymetric data are presented in support of this model which indicate: 1. (1) structural elements of the Mariana Trough extend north to the southern Volcano Arc. 2. (2) both the Mariana Trough and frontal arc shoal rapidly northwards as the Volcano Arc is approached. 3. (3) rugged bathymetry associated with the rifted Mariana Trough is replaced just south of Iwo Jima by the development of a huge dome (50-75 km diameter) centered around Iwo Jima. Such uplifted domes are the immediate precursors of rifts in other environments, and it appears that a similar situation may now exist in the southern Volcano Arc. The present distribution of unrifted Volcano Arc to the north and rifted Mariana Arc to the south is interpreted not as a stable tectonic configuration but as representing a tectonic "snapshot" of an arc in the process of being rifted to form a back-arc basin. ?? 1984.

Stern, R.J.; Smoot, N.C.; Rubin, M.

1984-01-01

350

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

351

University of Tokyo: Volcano Research Center (VRC)  

NSDL National Science Digital Library

This website discusses the Volcano Research Center's (VRC) work to improve predictions of volcanic eruptions by conducting research on volcanic processes. Users can find out about Asama, Kirishima, Izu-Oshima, and other VRC volcano observatories. The website features information on many continuing and recent eruptions in Japan. Visitors can view many images of volcanic eruptions and disaster relief missions. Researchers can learn about the international cooperative drilling operation at the Unzen Volcano to understand the eruption mechanisms and magnetic activity. This site is also reviewed in the February 20, 2004 _NSDL Physical Sciences Report_.

352

Lava Sampling on Kilauea Volcano, Hawaii  

NSDL National Science Digital Library

This video segment shows how scientists collaborate to collect and chemically analyze samples of molten lava as part of their quest to learn more about how volcanoes work. Working at Kilauea volcano, scientists collect samples of lava before it has a chance to cool so they can study the chemical properties it had when it was deep within Earth's interior. The samples are sent to a laboratory where other scientists determine their chemical compositions. Questions such as whether two volcanoes share a common magma source can be answered through such analyses. The segment is five minutes forty-seven seconds in length. A background essay and list of discussion questions are also provided.

353

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

354

Surface Deformation of Eyjafjallajokull Volcano During the 2009-2010 Unrest (Invited)  

NASA Astrophysics Data System (ADS)

On April 14 2010 an explosive eruption started from the summit of Eyjafjallajokull volcano. It was followed by a rapid deflation of the volcano observed both with GPS and InSAR data. The eruption was preceded by three months of volcanic unrest including an effusive flank eruption on March 20. The deformation of the volcano prior to the eruption was both spatially and temporally complex. It was monitored using data from continuous GPS stations and semi continuous GPS stations (logging 1 Hz data), TerraSAR-X images, and campaign GPS data. The first sign of renewed activity was observed around mid 2009 when seismicity picked up for a period of a few weeks and a continuous GPS station south of the volcano (THEY) moved 10-12 mm southward, suggesting inflation of the volcano. To monitor the activity two semi continuous stations were deployed during summer of 2009, one on the western flank of the volcano 17 km from the summit (HAMR) and another on the southeastern flank of the volcano 11 km from the summit (SKOG). After a few months pause the activity picked up again in the end of December 2009 with a more rapid southward motion of THEY and high seismic activity. In February THEY started moving in a more southwesterly direction and SKOG started to move toward southeast and up. At the same time a slight change in velocity was observed at station HAMR with the site moving in toward the volcano. In response to the enhanced deformation a new semi continuous GPS station was installed 5 km north of the volcano's summit (STE2). The station showed back and forth changes in the N-S component starting around the end of February but on March 4 the station started moving westward at a high rate. Rapid southward motion, some days exceeding 2 cm/day, and uplift were observed at station SKOG from March 13. On March 20 a 300 m long fissure opened up on the east flank of the volcano at Fimmvorduhals. In the hours prior the eruption, on March 19 and 20, two new semi continuous GPS stations had been installed 3 km south (FIM2) and 5 km north (BAS2) of where the eruptive fissure opened up. Deformation almost ceased when the fissure opened and the volcano remained at an inflated stage, without significant subsidence until 9 April. No detectable deformation was observed in TerraSAR-X interferograms spanning the flank eruption but interferogram from 2009/09/25 to 2010/03/20, spanning the pre-eruptive period, reveals the spatial extent of deformation and the cumulative amount just hours prior to the eruption. Subsidence occurred at station STE2 and BAS2 three days prior to the end of the flank eruption on April 12. The stations STE2 and BAS2 showed renewed inflation during a two-day hiatus in volcanic activity, until an explosive eruption began on 14 April at the ice-capped summit of the volcano.

Hreinsdottir, S.; Hooper, A.; Auriac, A.; Sigmundsson, F.; Hensch, M.; Arnadottir, T.; Roberts, M. J.; Sveinbjornsson, H.; Pedersen, R.; Geirsson, H.; Ofeigsson, B. G.; Sturkell, E. C.; Feigl, K.

2010-12-01

355

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

356

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 ...

357

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

358

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

359

Volcano Monitoring Using Google Earth  

NASA Astrophysics Data System (ADS)

At the Alaska Volcano Observatory (AVO), remote sensing is an important component of its daily monitoring of volcanoes. AVO’s remote sensing group (AVORS) primarily utilizes three satellite datasets; Advanced Very High Resolution Radiometer (AVHRR) data, from the National Oceanic and Atmospheric Administration’s (NOAA) Polar Orbiting Satellites (POES), Moderate Resolution Imaging Spectroradiometer (MODIS) data from the National Aeronautics and Space Administration’s (NASA) Terra and Aqua satellites, and NOAA’s Geostationary Operational Environmental Satellites (GOES) data. AVHRR and MODIS data are collected by receiving stations operated by the Geographic Information Network of Alaska (GINA) at the University of Alaska’s Geophysical Institute. An additional AVHRR data feed is supplied by NOAA’s Gilmore Creek satellite tracking station. GOES data are provided by the Naval Research Laboratory (NRL), Monterey Bay. The ability to visualize these images and their derived products is critical for the timely analysis of the data. To this end, AVORS has developed javascript web interfaces that allow the user to view images and metadata. These work well for internal analysts to quickly access a given dataset, but they do not provide an integrated view of all the data. To do this AVORS has integrated its datasets with Keyhole Markup Language (KML) allowing them to be viewed by a number of virtual globes or other geobrowsers that support this code. Examples of AVORS’ use of KML include the ability to browse thermal satellite image overlays to look for signs of volcanic activity. Webcams can also be viewed interactively through KML to confirm current activity. Other applications include monitoring the location and status of instrumentation; near real-time plotting of earthquake hypocenters; mapping of new volcanic deposits using polygons; and animated models of ash plumes, created by a combination of ash dispersion modeling and 3D visualization packages.

Cameron, W.; Dehn, J.; Bailey, J. E.; Webley, P.

2009-12-01

360

Earthquake sources near Uturuncu Volcano  

NASA Astrophysics Data System (ADS)

Uturuncu, located in southern Bolivia near the Chile and Argentina border, is a dacitic volcano that was last active 270 ka. It is a part of the Altiplano-Puna Volcanic Complex, which spans 50,000 km2 and is comprised of a series of ignimbrite flare-ups since ~23 ma. Two sets of evidence suggest that the region is underlain by a significant magma body. First, seismic velocities show a low velocity layer consistent with a magmatic sill below depths of 15-20 km. This inference is corroborated by high electrical conductivity between 10km and 30km. This magma body, the so called Altiplano-Puna Magma Body (APMB) is the likely source of volcanic activity in the region. InSAR studies show that during the 1990s, the volcano experienced an average uplift of about 1 to 2 cm per year. The deformation is consistent with an expanding source at depth. Though the Uturuncu region exhibits high rates of crustal seismicity, any connection between the inflation and the seismicity is unclear. We investigate the root causes of these earthquakes using a temporary network of 33 seismic stations - part of the PLUTONS project. Our primary approach is based on hypocenter locations and magnitudes paired with correlation-based relative relocation techniques. We find a strong tendency toward earthquake swarms that cluster in space and time. These swarms often last a few days and consist of numerous earthquakes with similar source mechanisms. Most seismicity occurs in the top 10 kilometers of the crust and is characterized by well-defined phase arrivals and significant high frequency content. The frequency-magnitude relationship of this seismicity demonstrates b-values consistent with tectonic sources. There is a strong clustering of earthquakes around the Uturuncu edifice. Earthquakes elsewhere in the region align in bands striking northwest-southeast consistent with regional stresses.

Keyson, L.; West, M. E.

2013-12-01

361

Lava bubble-wall fragments formed by submarine hydrovolcanic explosions on L?'ihi Seamount and K?lauea Volcano  

Microsoft Academic Search

Glassy bubble-wall fragments, morphologically similar to littoral limu o Pele, have been found in volcanic sands erupted\\u000a on L?'ihi Seamount and along the submarine east rift zone of K?lauea Volcano. The limu o Pele fragments are undegassed with\\u000a respect to H2O and S and formed by mild steam explosions. Angular glass sand fragments apparently form at similar, and greater, depths

David A. Clague; Alice S. Davis; James L. Bischoff; Jacqueline E. Dixon; Renee Geyer

2000-01-01

362

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

363

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

364

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.

365

A field guide to Newberry Volcano, Oregon  

USGS Publications Warehouse

Newberry Volcano is located in central Oregon at the intersection of the Cascade Range and the High Lava Plains. Its lavas range in age from ca. 0.5 Ma to late Holocene. Erupted products range in composition from basalt through rhyolite and cover ~3000 km2. The most recent caldera-forming eruption occurred ~80,000 years ago. This trip will highlight a revised understanding of the volcano's history based on new detailed geologic work. Stops will also focus on evidence for ice and flooding on the volcano, as well as new studies of Holocene mafic eruptions. Newberry is one of the most accessible U.S. volcanoes, and this trip will visit a range of lava types and compositions including tholeiitic and calc-alkaline basalt flows, cinder cones, and rhyolitic domes and tuffs. Stops will include early distal basalts as well as the youngest intracaldera obsidian flow.

Jenson, Robert A.; Donnelly-Nolan, Julie M.; McKay, Danielle

2009-01-01

366

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 A.; Webley, Peter; Freymueller, Jeff; Haney, Matthew; McNutt, Stephen; Schneider, David; Prejean, Stephanie; Schaefer, Janet; Wessels, Rick

2009-01-01

367

Eruption of Alaska Volcano Breaks Historic Pattern  

NASA Astrophysics Data System (ADS)

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

2009-05-01

368

Volcanology: A volcano's sharp intake of breath  

NASA Astrophysics Data System (ADS)

Shallow magma bodies that feed regularly erupting volcanoes are usually considered enduring features that grow steadily between eruptions. Measurements of deformation at Santorini, however, reveal sudden rapid magma accumulation after half a century of rest.

Hooper, Andrew

2012-10-01

369

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

370

Economic geology: Ore metals beneath volcanoes  

NASA Astrophysics Data System (ADS)

Metals often accumulate in the crust beneath volcanoes. Laboratory experiments and observations reveal important roles for magmatic vapours and brines in transporting and concentrating the metals into deposits worth targeting for extraction.

Nadeau, Olivier

2015-03-01

371

Major Martian Volcanoes from MOLA - Olympus Mons  

NASA Technical Reports Server (NTRS)

Two views of Olympus Mons, shown as topography draped over a Viking image mosaic. MOLA's regional topography has shown that this volcano sits off to the west of the main Tharsis rise rather than on its western flank. The topography also clearly shows the relationship between the volcano's scarp and massive aureole deposit that was produced by flank collapse. The vertical exaggeration is 10:1.

2000-01-01

372

Eruptions of Taal Volcano 1976-1977  

Microsoft Academic Search

Sixty kilometers due south of Manila, Philippines, hidden behind an ignimbrite delta, which at its rim is nearly 700-m high, is the active Taal Volcano. There is a lake of 267 km2 in the volcano-tectonic depression and within it an island of 25 km2. The island has been constructed largely by phreatomagmatic activity, added to in historic times. The last

John A. Wolfe

1980-01-01

373

Motivations for muon radiography of active volcanoes  

NASA Astrophysics Data System (ADS)

Muon radiography represents an innovative tool for investigating the interior of active volcanoes. This method integrates the conventional geophysical techniques and provides an independent way to estimate the density of the volcano structure and reveal the presence of magma conduits. The experience from the pioneer experiments performed at Mt. Asama, Mt. West Iwate, and Showa-Shinzan (Japan) are very encouraging. Muon radiography could be applied, in principle, at any stratovolcano. Here we focus our attention on Vesuvius and Stromboli (Italy).

Macedonio, G.; Martini, M.

2010-02-01

374

Miocene to Recent structural evolution of the Nevado de Toluca volcano region, Central Mexico  

NASA Astrophysics Data System (ADS)

Based on aerial photography, satellite imagery, and detailed field work, a geological and structural model of Nevado de Toluca and its surroundings is presented. The Nevado de Toluca volcano is built upon the intersection of three complex fault systems of different age, orientation, and kinematics. These systems from the older to the younger are: (a) The Taxco-Querétaro Fault System (NNW-SSE) with clear expression south of the volcano; (b) The San Antonio Fault System (NE-SW) that runs between the San Antonio and Nevado de Toluca volcanoes; and (c) The Tenango Fault System (E-W) located to the east of Nevado de Toluca volcano. Our field data, supported by previous studies, suggest that these systems have coexisted since the late Miocene. In addition, the stratigraphy, chronology, and kinematics of fault planes point to the existence of at least three main deformation events that have affected the region since the late Miocene. During the early Miocene, an extensional phase with the same deformation style as the Basin and Range tectonics of northern Mexico caused the formation of horsts and grabens south of Nevado de Toluca and allowed the intrusion of sub-vertical dikes oriented NW-SE and NNW-SSE. During the middle Miocene, a transcurrent episode generated NE-SW faults that presented two main motions: the first movement was left-lateral with a ?3 oriented NW-SE and later turned into normal through a counter-clockwise rotation of ?3 up to a N-S position. The latest deformation phase started during the late Pliocene and produced oblique extension ( ?3 oriented NE-SW) along E-W-trending faults that later changed to pure extension by shifting of ?3 to a N-S orientation. These faults appear to control the late Pleistocene to Holocene monogenetic volcanism, the flank collapses of Nevado de Toluca volcano and the seismic activity of the region.

García-Palomo, A.; Macías, J. L.; Garduño, V. H.

2000-03-01

375

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

376

Changbai intraplate volcanism and deep earthquakes in East Asia: a possible link?  

NASA Astrophysics Data System (ADS)

The origin of intraplate volcanoes in Northeast Asia is considered to be associated with upwelling of hot and wet asthenospheric materials in the big mantle wedge above the stagnant Pacific slab in the mantle transition zone. Among these intraplate volcanoes, Changbai is the largest and most active one, and very deep earthquakes (500-650 km depths) in the Pacific slab under East Asia occur ˜300 km to the east of the Changbai volcano. Integrating the findings of geophysical, geochemical and petrologic studies so far, we suggest a link between Changbai volcanism and the deep earthquakes in the Pacific slab. Many large shallow earthquakes occurred in the Pacific Plate in the outer-rise areas close to the oceanic trench, and sea water may enter down to a deep portion of the oceanic lithosphere through the active normal faults which generated the large outer-rise earthquakes. Sea water or fluids may be preserved in the active faults even after the Pacific Plate subducts into the mantle. Many large deep earthquakes are observed that took place in the subducting Pacific slab under the Japan Sea and the East Asian margin. At least some of the large deep earthquakes are caused by the reactivation of faults preserved in the subducting slab, and the fluids preserved in the faults within the slab may cause the observed non-double-couple components of the deep earthquake faulting. Fluids preserved in the slab may be released to the overlying mantle wedge through large deep earthquakes. Because large deep earthquakes occur frequently in the vicinity of the Changbai volcano, many more fluids could be supplied to this volcano than in other areas in Northeast Asia, making Changbai the largest and most active intraplate volcano in the region.

Zhao, Dapeng; Tian, You

2013-11-01

377

What controls earthquakes at Aleutian arc volcanoes?  

NASA Astrophysics Data System (ADS)

Alaska has around 100 Holocene active volcanoes spread over 3000 km of the Aleutian arc, from Mount Wrangell in southcentral Alaska to Buldir Island in the western Aleutian islands. The range in volcanic styles across the arc is as great as the distance that it spans, and so too is the accompanying volcano seismicity. This study examines whether there are systematic influences on volcano seismicity across the Aleutian arc that can account for distinctive patterns in earthquake behaviour, such as the paucity of deep (>20 km depth) volcanic earthquakes in the Cook Inlet region compared to volcanic earthquakes at the westernmost portion of the Alaska Peninsula. We investigate whether physical factors such as volcano size, geographic location relative to the subduction zone, the regional setting - including the type of crust and the distance between the vent and the ocean - and the local angle and rate of subduction affect volcano seismicity. We use continuous seismic data recorded over a 10-year period at 47 volcanoes to characterise patterns in seismicity. Our analyses consider the number and locations of hypocenters, waveform characteristics such as frequency content and magnitude, and the frequency and style of volcanic unrest during the study period.

Buurman, H.; West, M. E.; Cameron, C.

2012-12-01

378

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

379

Ambient Noise Tomography at Bezymianny Volcano, Kamchatka  

NASA Astrophysics Data System (ADS)

Bezymianny Volcano is an active stratovolcano located in the Kluychevskoy volcanic group on the Kamchatka Peninsula in eastern Russia. Since its dramatic sector collapse eruption in 1956, the volcano's activity has been characterized by nearly twice annual plinian eruptions accompanying ongoing lava-dome growth. Its frequent eruptions and similarity to Mt. St. Helens have made it the target of a multifaceted geologic and geophysical project supported by the NSF Partners in Research and Education (PIRE) program. Since mid- 2006, the volcano has been monitored by a broadband seismic array that is currently composed of 8 stations within 10 kilometers of the active dome. In this project, we use continuous data from these stations to investigate the static and dynamic structure of the volcano. Using methods similar to those used by Brenguier et al. (2007, 2008), we estimate the Green's function for each pair of stations by cross-correlating day-long time series of ambient noise. Paths with high signal-to-noise ratios can be used to estimate group velocity dispersion curves. From these measurements, we work towards constructing the first velocity model of this volcano. Furthermore, we begin to test whether measurements of ambient noise can be used to monitor changes inside the volcano prior to eruptive activity. These problems will continue to be addressed as more data becomes available in future field seasons.

Shuler, A. E.; Ekström, G.; West, M.; Senyukov, S.

2008-12-01

380

Dynamic Submarine Flanks of Hualalai Volcano, Hawaii  

NASA Astrophysics Data System (ADS)

Four remote and manned submersible dives examined the Hualalai midslope bench scarps, NW rift zone, and an elongate ridge cresting at 3900 mbsl during 2001 and 2002 JAMSTEC cruises. Here we report the results of stratigraphic, petrographic, and geochemical studies of the latter feature (dive S692). The ridge is 2x8 km, 300-700 m above datum, oriented parallel to the midslope bench, and 1 km east of the Mauna Loa Alika 2 landslide chute and levee deposit. Although the vast majority of the ridge is sediment covered, dive videos and sampling of the steep seaward side of the ridge revealed the following in-place lithologies, from base to crest: (1) bedded, landward dipping glass sandstones consisting of arcuate, angular to subangular glasses, moderately vesicular, tholeiitic and fairly uniform in composition, dominantly low in S, and intensely chemically altered toward the base, (2) olivine basalt breccia with fresh tholeiite glassy matrix, including S-rich grains, (3) dense olivine basalt lava blocks, (4) coarsely crystalline, vesicular, and oxidized lava, and (5) a capping unit of layered, volcaniclastic siltstone beds rich in radiolarians. Finally, an apron of talus and a superficial coating of muddy clastic materials drape the base of the ridge. Samples of this material are compositionally distinct from the in-place samples: they include transitional basalt and S-rich hawaiite. Key inferences about the ridge deposits are: (1) glass sands were produced as shield stage Hualalai lava erupted subaerially or in shallow water, (2) sands were cemented and overlain by breccia and lava blocks following minimal transport as grain flows to a depth that allowed incorporation of high-S grains; the entire sequence was transported to its current deep water location as a coherent package, (3) the zone of intense hydrothermal alteration and mineralization at the base is consistent with fluid flow in a region of distributed strain, possibly associated with gravitational spreading of Hualalai volcano, (4) the alkalic and transitional materials may represent pre-shield Hualalai volcanism. Alternatively, they could represent pre-shield Mauna Loa lavas excavated and transported to their present location by the Alika 2 landslide, which truncated the package, exposed the observed outcrop, and capped the sequence with fossiliferous glassy silt.

Hammer, J. E.; Shamberger, P. J.

2003-12-01

381

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

382

Living with volcanoes: The sustainable livelihoods approach for volcano-related opportunities  

Microsoft Academic Search

Although the negative impacts of volcanism on society are well documented and accepted, many possible benefits from volcanoes are not always fully considered. This paper provides suggestions for understanding and implementing volcanoes' benefits by suggesting further application of existing risk management frameworks to volcanology: living with risk by using the sustainable livelihoods approach at the local level. This paper presents

Ilan Kelman; Tamsin A. Mather

2008-01-01

383

Research paper Living with volcanoes: The sustainable livelihoods approach for volcano-related opportunities  

Microsoft Academic Search

Although the negative impacts of volcanism on society are well documented and accepted, many possible benefits from volcanoes are not always fully considered. This paper provides suggestions for understanding and implementing volcanoes' benefits by suggesting further application of existing risk management frameworks to volcanology: living with risk by using the sustainable livelihoods approach at the local level. This paper presents

Ilan Kelman; Tamsin A. Mather

384

Consequences of local surface load variations for volcanoes monitoring: Application to Icelandic subglacial volcanoes  

Microsoft Academic Search

Surface load variations occur frequently in the vicinity of volcanoes inducing deformations and stress field perturbations that might be recorded by geophysical monitoring. One of the main limitations of risk assessment from volcanoes continuous monitoring is our ability to establish whether or not a given perturbation of the signal is a precursor announcing an eruptive event. To obtain maximum benefits

F. Albino; V. Pinel; F. Sigmundsson

2009-01-01

385

The implementation of a volcano seismic monitoring network in Sete Cidades Volcano, São Miguel, Açores  

Microsoft Academic Search

Sete Cidades is one of the three active central volcanoes of S. Miguel Island, in the Azores archipelago. With a 5 kilometres wide caldera, it has the highest eruptive record in the last 5000 years with 17 intracaldera explosive events (Queiroz, 1997). Only submarine volcanic eruptions occurred in Sete Cidades volcano-tectonic system since the settlement of the island, in the

N. Wallenstein; A. Montalvo; U. Barata; R. Ortiz

2003-01-01

386

A seismological comparison of Bezymianny Volcano, Russia, and Mount St. Helens Volcano, Washington  

Microsoft Academic Search

Bezymianny Volcano, Russia and Mount St. Helens, Washington are examples of eruptions involving the sector collapse of a volcano. The study and comparison of Mount St. Helens and Bezymianny has led to a better understanding of the precursory seismicity prior to eruptions. The shallow moment release prior to an eruption is dependent on the time since the last eruption at

Weston Albert Thelen

2009-01-01

387

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

388

The seismicity of Marapi volcano, West Sumatra.  

NASA Astrophysics Data System (ADS)

Marapi is one of the active volcanoes in West Sumatra. It is a stratovolcano with an edifice that is elongated in the ENE-WSW direction. Its elevation is about 2,900 m a.s.l. The summit area is characterized by a caldera that contains some active craters aligned along the ENE-WSW direction. The Marapi volcano is an attractive region for tourists and hosts many small communities its surrounding areas. The recent history of Mt. Marapi is characterized by explosive activity at the summit craters. No lava flows have passed the rim of the summit caldera in recent times. The last eruption occurred on August 5, 2004, and consisted of moderate explosive activity from the central crater. In 1975 an eruption with magmatic and phreatic explosive phases and mudflows and lahars occurred that caused fatalities in the surrounding areas. Since 1980 other eruptions have occurred at Marapi volcano. Even if the explosive intensities of those eruptions have been small to moderate, in some cases, there were fatalities. A cooperation project started between Italy and Indonesia (COVIN) for the monitoring of volcanoes in West Sumatra. In the context of this project a monitoring centre has been set up at the Bukittinggi Observatory and a seismological monitoring system for Marapi volcano has been realized. This system is based on a broadband seismic network including 4 three-component stations. The data acquired by the broadband network of Marapi volcano are continuous recordings of the seismic signals starting from 19/10/2006. Volcano-Tectonic and Long Period events of Marapi volcano together with regional and teleseismic earthquakes are recorded. Several events of high magnitude located at short distances from the network were also recorded such as on March 6, 2007, when two events of Magnitudes Mw 6.4 and 6.3 were recorded with the epicentres near the Marapi volcano. During the following days, there was a sequence of hundreds of aftershocks. The preliminary analysis of the seismicity of the Marapi Volcano indicates that the broadband network installed under the joint Italy-Indonesia project provides great help for its study and for the monitoring of this active volcanic and seismogenic area.

D'Auria, L.

2009-04-01

389

Sulphur budget at Poàs volcano  

NASA Astrophysics Data System (ADS)

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 lake level, temperature and composition, ground deformation, micro-gravity, river and gas flux and composition, can help to estimate the total sulphur budget of the magmatic system. Sulphur from the magma enters a brine which feeds the Rio Agrio on the west flank of the volcanic edifice. The extreme acidity of the hydrothermal system (pH ~ 0-0.5) enhances the permeability of the summit area (loss of 1650 m3.y-1 in this zone; Rowe et al., 1992). The lack of ground deformation suggests that most of the voids are filled by mineral deposition in order to maintain the yield strength of the volcanic deposits. Previous studies show that the calculated precipitation of liquid sulphur at equilibrium, largely exceeds the deposition amount required to maintain a lower porosity. Based on the constant lake level, temperature and chemistry, as well as the calculated sulphur input and output in the lake between 1995 and 2001, an annual budget of approximately 11x103 tonnes of magmatic S entering the lake is required. COSPEC measurements for March 2001give minimum SO2 flux of ~ 40 t/d. This flux is of the same magnitude as the flux measured by Andres et al. in 1991. Assuming that this flux was relatively constant during the last 6 years (consistent with visual observations), it implies a mean annual S output of 7200 tonnes as SO2(g). As it is extremely difficult to remove SO2 from a hydrothermal system (Symonds et al., 2001), the total SO2 budget must come from the magma. The corresponding volume of degassed magma is ~3.9x10-3 km3 per year. The negligible volume of degassed magma, required to insure a balance of the sulphur budget, can be either recycled at depth by convection in the conduit or accreted within the edifice (consistent with low micro-gravity variations due to magma movement since 1995; Rymer et al., 2000). Therefore, the magma feeding at Poàs volcano appears to be in low steady state regime.

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

2001-12-01

390

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

391

Linear volcanic segments in the central Sunda Arc, Indonesia, identified using Hough Transform analysis: Implications for arc lithosphere control upon volcano distribution  

NASA Astrophysics Data System (ADS)

Hough Transform analysis is used as an objective means to constrain volcano distribution in the central Sunda Arc, Indonesia. Most volcanoes in the arc define four en echelon, linear segments, each of 500-700 km length. Javan volcanoes that do not lie on these segments either (i) formed at an early stage in the history of the arc and erupted products that are petrologically and geochemically distinct from typical arc magma, or (ii) lie along other mapped structures. The en echelon distribution of volcanoes in the central Sunda Arc is best explained as originating from two possible sources. First, interaction with the subducting Indo-Australian Plate may induce stress in the arc lithosphere generating pathways for magma to exploit. Second, downward flexure of the arc lithosphere, as a result of mantle flow or loading by the arc, would also establish arc-normal tension towards the base of the lithosphere, where magma is supplied to volcanic systems. To the west and east of the central Sunda Arc deviations from the distribution of long, en echelon, linear segments can be understood as responses to specific stress fields in the arc lithosphere of Sumatra and eastern Nusa Tenggara, respectively. Control of volcano distribution by arc lithosphere explains why there are large variations in the depth from volcanoes to the zone of slab seismicity in the central Sunda Arc, where there is little variation in slab geometry or the rate of plate convergence.

Pacey, Adam; Macpherson, Colin G.; McCaffrey, Ken J. W.

2013-05-01

392

Classification of Martian Volcanoes on Basis of Volcano Ground Ice Interaction  

NASA Astrophysics Data System (ADS)

Most Martian volcanoes have common morphological features indicating mass wasting and erosion compatible with large scale break down of ground ice. While some features suggest the ground ice melted rapidly resulting in catastrophic erosive events, other features indicate a slow melting process (e.g sublimation) resulting in collapse structures. To determine relative volcano age and activity on Mars it is suggested that volcano interactions with an overlying ice sheet may be helpful. Examples of the various morphological features indicating volcano-ice interaction are drawn from the literature: (1) valley formation that probably formed in response to joekulhlaups and subglacial volcanism, (2) isolated thermocarst depressions probably formed by geothermal melting of ground ice, (3) large scale sublimation of distal strata, (4) small fluvial valleys, (5) large scale failure of volcano flanks through aureole development, (6) rimless craters without ash collars, (7) rampart craters on volcanoes, (8) channels, (9) mud flows or lahars. A Viking Orbiter image showing possible thermocarst landscape on the flank of the volcano Hadriaca Patera (Dao Vallis). Although various other explanations can account for some of these features they are all compatible with a ground ice-volcano interaction. These features suggests that to an extent most Martian volcanoes are covered with sheet of ground ice of variable thickness. Over a vast time interval this ground ice layer (or ice sheet) has been failing to a variable extent and in a number of ways depending on different volcano characteristics. As a result it is suggested that Martian volcanoes can be classified or assigned an evolutionary status depending on how widespread their interaction is with the ground ice layer. Thus, for example, within the Tharsis region the volcanoes Olympus Mons and Arsia Mons can be regarded as two evolutionary end points. Volcanism in the former has completely built up through and destroyed the ice sheet over the source area but is at a very early stage in doing so at the latter. This method could provide valuable information on the relative ages of Martian volcanoes where age dating by counting impact craters is probably of but minor value due to lava or sedimentary accumulation and impact crater burial.

Helgason, J.

2000-08-01

393

Three-dimensional Q for Sierra Negra volcano, Galapagos  

NASA Astrophysics Data System (ADS)

Galapagos Islands volcanoes are some of the most rapidly deforming volcanoes on Earth, yet the magma storage chambers and migration pathways are poorly imaged. Three-dimensional tomographic inversion for seismic attenuation, 1/Q, is used to image variations in subsurface structure and heterogeneity associated with magma storage and volcanic construction at Sierra Negra volcano, Galapagos Islands. P-wave power spectra were used to estimate t* (attenuation weighted, integrated slowness) in the frequency domain for local earthquakes recorded on the 15 station, broadband SIGNET array. The SIGNET network was deployed around Sierra Negra caldera and the southern part of Isabela Island between August 2009 and January 2011. A subset of 451 earthquakes was selected for attenuation analysis based on event location within the array and station coverage. The modelled spectra were used to calculate path attenuation and earthquake source parameters. The earthquake source parameters corresponding to amplitude at zero frequency (?0) and corner frequency (fc) relate to earthquake size and are therefore set constant across stations. Accordingly, we derive a single ?0 and fc for each event and fix them while allowing only t* to vary. Values of t* range between 8.89 x 10-15 and 0.0525. Preliminary results show an increase in attenuation beneath the caldera starting at 1 km depth. The zone of high attenuation is more pronounced at 2 km depth and extends laterally to the east and southeast beyond the extent of the 10 km-wide caldera. Gravity anomaly and InSAR data has been used previously to model the magma chamber at Sierra Negra. Deformation modelling requires a flat-topped sill at 2 km depth (Geist et. al., 2007; Jonsson, S., 2009; Yun et. al., 2006). Our shallow, high attenuation zone matches these results, but also indicates that the attenuating bodies extend beyond the limits of the caldera beneath the SE flank of Sierra Negra. Elongate zones of higher attenuation correlate with aligned chains of cinder cones and fissures, including the E-W trending 2005 eruptive vent system.

Young, B. E.; Lees, J. M.; Ebinger, C. J.

2012-12-01

394

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...

395

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

396

Online Courses: Mississippi State University: Earthquakes and Volcanoes  

NSDL National Science Digital Library

Earthquakes and Volcanoes is intended as an investigation into the main processes and products of earthquakes and volcanoes within the framework of plate tectonics. The goals of the course include (1) the application of scientific principles to the study

1900-01-01

397

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

398

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

399

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

400

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.

Joseph Russo

2010-01-01

401

Syn and posteruptive hazards of maar–diatreme volcanoes  

Microsoft Academic Search

Maar–diatreme volcanoes represent the second most common volcano type on continents and islands. This study presents a first review of syn- and posteruptive volcanic and related hazards and intends to stimulate future research in this field. Maar–diatreme volcanoes are phreatomagmatic monogenetic volcanoes. They may erupt explosively for days to 15 years. Above the preeruptive surface a relatively flat tephra ring forms.

Volker Lorenz

2007-01-01

402

Swift snowmelt and floods (lahars) caused by great pyroclastic surge at Mount St Helens volcano, Washington, 18 May 1980  

USGS Publications Warehouse

The initial explosions at Mount St. Helens, Washington, on the moring of 18 May 1980 developed into a huge pyroclastic surge that generated catastrophic floods off the east and west flanks of the volcano. Near-source surge deposits on the east and west were lithic, sorted, lacking in accretionary lapilli and vesiculated ash, not plastered against upright obstacles, and hot enough to char wood - all attributes of dry pyroclastic surge. Material deposited at the surge base on steep slopes near the volcano transformed into high-concentration lithic pyroclastic flows whose deposits contain charred wood and other features indicating that these flows were hot and dry. Stratigraphy shows that even the tail of the surge had passed the east and west volcano flanks before the geomorphically distinct floods (lahars) arrived. This field evidence undermines hypotheses that the turbulent surge was itself wet and that its heavy components segregated out to transform directly into lahars. Nor is there evidence that meters-thick snow-slab avalanches intimately mixed with the surge to form the floods. The floods must have instead originated by swift snowmelt at the base of a hot and relatively dry turbulent surge. Impacting hot pyroclasts probably transferred downslope momentum to the snow surface and churned snow grains into the surge base. Melting snow and accumulating hot surge debris may have moved initially as thousands of small thin slushflows. As these flows removed the surface snow and pyroclasts, newly uncovered snow was partly melted by the turbulent surge base; this and accumulating hot surge debris in turn began flowing, a self-sustaining process feeding the initial flows. The flows thus grew swiftly over tens of seconds and united downslope into great slushy ejecta-laden sheetfloods. Gravity accelerated the floods to more than 100 km/h as they swept down and off the volcano flanks while the snow component melted to form great debris-rich floods (lahars) channeled into valleys. ?? 1989 Springer-Verlag.

Waitt, R.B.

1989-01-01

403

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

404

The role of mud volcanoes in the evolution of Hecate Tholus Volcano on the surface of Mars  

NASA Astrophysics Data System (ADS)

Hecate Tholus Volcano has undergone numerous changes in its history of evolution. Further, the phenomena occurring on the surface of this volcano endow us with a remarkable perspective of recent martian geological changes. In the vicinity of this volcano cone, most of the lava is covered with a thick layer of loose sediments (probably clay). The presence of such sediments at the base of the volcano cone has led to the formation of several major landslides. Moreover, liquid water flow on the volcano cone has created a myriad of radial channels. The formation of such structures on the cone of a volcano is only plausible as a result of eruption of a mud volcano from its crater. Besides, the constant discharge of mud-like materials as well as hot water from the volcano paves the way for the growth and evolution of hydrothermal organisms.

Kangi, Abas

2007-04-01

405

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.

406

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

407

Learning in Icelandic volcanoes Mathematical vineyard Chemistry magic  

E-print Network

Spring2010 Learning in Paradise Icelandic volcanoes Mathematical vineyard Chemistry magic #12 to study the Hekla volcano. As I write, another volcano in Iceland has just erupted, throwing ash over the projects our stu- dents and faculty members undertake have implications and benefits world-wide. EUREKA

Dawson, Jeff W.

408

Satellite monitoring of remote volcanoes improves study efforts in Alaska  

Microsoft Academic Search

Satellite monitoring of remote volcanoes is greatly benefitting the Alaska Volcano Observatory (AVO), and last year's eruption of the Okmok Volcano in the Aleutian Islands is a good case in point. The facility was able to issue and refine warnings of the eruption and related activity quickly, something that could not have been done using conventional seismic surveillance techniques, since

K. Dean; M. Servilla; A. Roach; B. Foster; K. Engle

1998-01-01

409

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

410

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 ...

411

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

412

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

413

Fidelity and Yield in a Volcano Monitoring Sensor Network  

E-print Network

Fidelity and Yield in a Volcano Monitoring Sensor Network Geoff Werner-Allen , Konrad Lorincz at Reventador, an active volcano in Ecuador. Each of the 16 sensors continuously sampled seismic and acoustic by the network. Typical volcano monitoring studies employ GPS- synchronized data loggers recording both seismic

Chen, Yiling

414

Worldwide distribution of submarine mud volcanoes and associated gas hydrates  

Microsoft Academic Search

The list of known and inferred submarine mud volcanoes is presented in this paper. They occur worldwide on shelves, continental and insular slopes and in the abyssal parts of inland seas. Submarine mud volcanoes are distributed on the Earth more extensively than their subaerial analogs. The estimated total number of known and inferred deep-water mud volcanoes is 103–105. There are

A. V Milkov

2000-01-01

415

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 7, 101 Reykjavi´k, Iceland d Volcano Dynamics Group, Department of Earth Sciences, The Open; received in revised form 19 December 2004 Abstract Here we review the achievements of volcano geodesy

Pedersen, Rikke

416

Predicting the Timing and Location of the next Hawaiian Volcano  

ERIC Educational Resources Information Center

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…

Russo, Joseph; Mattox, Stephen; Kildau, Nicole

2010-01-01

417

How Do Volcanoes Affect Human Life? Integrated Unit.  

ERIC Educational Resources Information Center

This packet contains a unit on teaching about volcanoes. The following question is addressed: How do volcanoes affect human life? The unit covers approximately three weeks of instruction and strives to present volcanoes in an holistic form. The five subject areas of art, language arts, mathematics, science, and social studies are integrated into…

Dayton, Rebecca; Edwards, Carrie; Sisler, Michelle

418

Historical 3D Topographic Reconstruction of the Iwaki Volcano  

E-print Network

Historical 3D Topographic Reconstruction of the Iwaki Volcano using Structure from Motion from of topographiy that may change drastically in a short-time such as volcanoes. Precise topographic data is testing the technique at the Iwaki volcano in Northern Honshu in Japan, using a series of historical

Paris-Sud XI, Université de

419

The youngest eruptions and edifice collapse of Iriga volcano, Philippines  

E-print Network

The youngest eruptions and edifice collapse of Iriga volcano, Philippines Alexander Belousov 1 of Volcanology and Seismology, Petropavlovsk, Russia, 3 ­ University of Philippines Iriga volcano has a prominent one of small lakes formed on top of the debris avalanche deposit. This implies that the volcano

Belousov, Alexander

420

What's this volcano trying to tell us? by Daniel Pendick  

E-print Network

What's this volcano trying to tell us? by Daniel Pendick Tue, 1 Dec 1998 Deep gurgles and belches, tropical slopes of Arenal volcano in Costa Rica, clouds of moisture hang above the trees like a blanket. There's danger in the air too: the volcano's dark cone looms over nearby towns and villages, and has

Buckingham, Michael

421

Encapsulation of Parallelism in the Volcano Query Processing System  

Microsoft Academic Search

Volcano 1s a new dataflow query processmg system we have developed for database systems research and educauon The umform Interface between operators makes Volcano extenstble by new operators All operators are designed and coded as d they were meant for a smgle-process system only When attemptmg to parallelue Volcano, we had to choose between two models of parallchzatlon, called here

Goetz Graefe

1990-01-01

422

PUBLICATIONS OF THE VOLCANO HAZARDS PROGRAM 1999-2003  

E-print Network

PUBLICATIONS OF THE VOLCANO HAZARDS PROGRAM 1999-2003 2003 UNITED STATES DEPARTMENT OF THE INTERIOR UNITED STATES GEOLOGICAL SURVEY #12;2 The Volcano Hazards Program of the U.S. Geological Survey (USGS;3 Volcano Hazards Bibliography 1999-2003 Adleman, Jennifer, 2002, The great eruption of 1912: Alaska Park

Torgersen, Christian

423

Overview of the 1990–1995 eruption at Unzen Volcano  

Microsoft Academic Search

Following 198 years of dormancy, a small phreatic eruption started at the summit of Unzen Volcano (Mt. Fugen) in November 1990. A swarm of volcano-tectonic (VT) earthquakes had begun below the western flank of the volcano a year before this eruption, and isolated tremor occurred below the summit shortly before it. The focus of VT events had migrated eastward to

Setsuya Nakada; Hiroshi Shimizu; Kazuya Ohta

1999-01-01

424

REDUCING THE RISK FROM VOLCANO HAZARDS UNITED STATES GEOLOGICAL SURVEY  

E-print Network

REDUCING THE RISK FROM VOLCANO HAZARDS UNITED STATES GEOLOGICAL SURVEY VolcanicAsh--Danger toAircraft intheNorthPacific The world's busy air traffic corridors pass over hundreds of volcanoes ca- pable and millions of dollars of cargo over volcanoes each day. Volcanic ash can be a serious hazard to aviation even

Torgersen, Christian

425

Global Volcano Proportional Economic Loss Risk Distribution Projection: Robinson  

E-print Network

Global Volcano Proportional Economic Loss Risk Distribution Projection: Robinson Like Total to volcanoes for each grid cell by a vulnerability coefficient to obtain an estimate of risk. The vulnerability Analysis. Washington, D.C.: World Bank. Source: Volcano Proportional Economic Loss Risk Deciles 1 st ­4 th

Columbia University

426

Monitoring Volcanic Activity at Reventador Volcano, Ecuador with a  

E-print Network

Monitoring Volcanic Activity at Reventador Volcano, Ecuador with a Wireless Sensor Network Geoff of the erupting volcano Automatic triggering to download data following seismic events Tested sophisticated data.g., tomography -- image interior of volcano using wave arrivals at many locations #12;© 2005 Matt Welsh ­ Harvard

Chen, Yiling

427

Global Volcano Total Economic Loss Risk Distribution Projection: Robinson  

E-print Network

Global Volcano Total Economic Loss Risk Distribution Projection: Robinson Total Economic Loss is found by weighting the value of GDP exposure to volcanoes for each grid cell by a vulnerability International Bank for Reconstruction and Development/The World Bank and Columbia University. Volcano Total

Columbia University

428

G188 Research Paper Volcano Tourism: Hazards and Mitigation  

E-print Network

Madi McNew G188 Research Paper 6/14/14 Volcano Tourism: Hazards and Mitigation ABSTRACT The Long of visitors each year. The various products and effects of volcanoes make hazards unavoidable. Regardless, monitoring and mitigation of the volcanoes are necessary in order to protect the residents and tourists

Polly, David

429

Mount St. Helens volcano: Recent and future behavior  

USGS Publications Warehouse

Mount St. Helens volcano in southern Washington has erupted many times during the last 4000 years, usually after brief dormant periods. This behavior pattern suggests that the volcano, last active in 1857, will erupt again - perhaps within the next few decades. Potential volcanic hazards of several kinds should be considered in planning for land use near the volcano.

Crandell, D.R.; Mullineaux, D.R.; Rubin, M.

1975-01-01

430

ASAR images a diverse set of deformation patterns at Ki??lauea volcano, Hawai'i  

USGS Publications Warehouse

Since 2003, 27 independent look angles have been acquired by ENVISAT's Advanced Synthetic Aperture Radar (ASAR) instrument over the island of Hawai'i, allowing for the formation of thousands of interferograms showing deformation of the ground surface. On Ki??lauea volcano, a transition from minor to broad-scale summit inflation was observed by interferograms that span 2003 to 2006. In addition, radar interferometry (InSAR) observations of Ki??lauea led to the discovery of several previously unknown areas of localized subsidence in the caldera and along the volcano's east rift zone. These features are probably caused by the cooling and contraction of accumulated lavas. After November 2005, a surface instability near the point that lava entered the ocean on the south flank of Ki??lauea was observed in interferograms. The motion is most likely a result of unbuttressing of a portion of the coast following the collapse of a large lava delta in November 2005. InSAR data can also be used to map lava flow development over time, providing ???30 m spatial resolution maps at approximately monthly intervals. Future applications of InSAR to Ki??lauea will probably result in more discoveries and insights, both as the style of volcano deformation changes and as data from new instruments are acquired.

Poland, Michael P.

2007-01-01

431

Volcanoes: Can We Predict Volcanic Eruptions?  

NSDL National Science Digital Library

This volcanoes site provides information about volcanoes as well as a classroom activity. There are video clips which show some of the features discussed, such as types of lava and eruptive styles. Topics covered by the text include how rocks melt, where and why volcanoes occur (plate tectonics), hot spots, volcanic hazards, forecasting eruptions and coping with risk. The classroom exercise involves deciding whether or not to build developments near volcanic features. Students are provided with maps, geologic data and helpful hints. Once the decision is made, students must defend their decisions at a press conference, complete with reporter's questions and a printout of the resulting news stories. This exercise illustrates the connection between science and public policy.

2002-06-10

432