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Sample records for active volcano mount

  1. Mount Rainier active cascade volcano

    NASA Technical Reports Server (NTRS)

    1994-01-01

    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.

  2. Monitoring Mount Baker Volcano

    USGS Publications Warehouse

    Malone, S.D.; Frank, D.

    1976-01-01

    Hisotrically active volcanoes in the conterminous United States are restricted to the Cascade Range and extend to the Cascade Range and extend from Mount Baker near the Canadian border to Lassen Peak in northern California. Since 1800 A.D, most eruptive activity has been on a relatively small scale and has not caused loss of life or significant property damage. However, future  volcanism predictably will have more serious effects because of greatly increased use of land near volcanoes during the present century. (See "Appraising Volcanic Hazards of the Cascade Range of the Northwestern United States," Earthquake Inf. Bull., Sept.-Oct. 1974.) The recognition an impending eruption is highly important in order to minimize the potential hazard to people and property. Thus, a substantial increase in hydrothermal activity at Mount Baker in March 1975 ( see "Mount Baker Heating Up," July-Aug. 1975 issue) was regarded as a possible first signal that an eruption might occur, and an intensive monitoring program was undertaken. 

  3. Erupting Volcano Mount Etna

    NASA Technical Reports Server (NTRS)

    2001-01-01

    An Expedition Two crewmember aboard the International Space Station (ISS) captured this overhead look at the smoke and ash regurgitated from the erupting volcano Mt. Etna on the island of Sicily, Italy. At an elevation of 10,990 feet (3,350 m), the summit of the Mt. Etna volcano, one of the most active and most studied volcanoes in the world, has been active for a half-million years and has erupted hundreds of times in recorded history.

  4. Erupting Volcano Mount Etna

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Expedition Five crew members aboard the International Space Station (ISS) captured this overhead look at the smoke and ash regurgitated from the erupting volcano Mt. Etna on the island of Sicily, Italy in October 2002. Triggered by a series of earthquakes on October 27, 2002, this eruption was one of Etna's most vigorous in years. This image shows the ash plume curving out toward the horizon. The lighter-colored plumes down slope and north of the summit seen in this frame are produced by forest fires set by flowing lava. At an elevation of 10,990 feet (3,350 m), the summit of the Mt. Etna volcano, one of the most active and most studied volcanoes in the world, has been active for a half-million years and has erupted hundreds of times in recorded history.

  5. Mount Rainier, a decade volcano

    SciTech Connect

    Kuehn, S.C.; Hooper, P.R. . Dept. of Geology); Eggers, A.E. . Dept. of Geology)

    1993-04-01

    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.

  6. Preliminary volcano-hazard assessment for Mount Spurr Volcano, Alaska

    USGS Publications Warehouse

    Waythomas, Christopher F.; Nye, Christopher J.

    2001-01-01

    Mount Spurr volcano is an ice- and snow-covered stratovolcano complex located in the north-central Cook Inlet region about 100 kilometers west of Anchorage, Alaska. Mount Spurr volcano consists of a breached stratovolcano, a lava dome at the summit of Mount Spurr, and Crater Peak vent, a small stratocone on the south flank of Mount Spurr volcano. Historical eruptions of Crater Peak occurred in 1953 and 1992. These eruptions were relatively small but explosive, and they dispersed volcanic ash over areas of interior, south-central, and southeastern Alaska. Individual ash clouds produced by the 1992 eruption drifted east, north, and south. Within a few days of the eruption, the south-moving ash cloud was detected over the North Atlantic. Pyroclastic flows that descended the south flank of Crater Peak during both historical eruptions initiated volcanic-debris flows or lahars that formed temporary debris dams across the Chakachatna River, the principal drainage south of Crater Peak. Prehistoric eruptions of Crater Peak and Mount Spurr generated clouds of volcanic ash, pyroclastic flows, and lahars that extended to the volcano flanks and beyond. A flank collapse on the southeast side of Mount Spurr generated a large debris avalanche that flowed about 20 kilometers beyond the volcano into the Chakachatna River valley. The debris-avalanche deposit probably formed a large, temporary debris dam across the Chakachatna River. The distribution and thickness of volcanic-ash deposits from Mount Spurr volcano in the Cook Inlet region indicate that volcanic-ash clouds from most prehistoric eruptions were as voluminous as those produced by the 1953 and 1992 eruptions. Clouds of volcanic ash emitted from the active vent, Crater Peak, would be a major hazard to all aircraft using Ted Stevens Anchorage International Airport and other local airports and, depending on wind direction, could drift a considerable distance beyond the volcano. Ash fall from future eruptions could disrupt many

  7. Mount st. Helens volcano: recent and future behavior.

    PubMed

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

    1975-02-07

    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.

  8. Renewed unrest at Mount Spurr Volcano, Alaska

    USGS Publications Warehouse

    Power, John A.

    2004-01-01

    The Alaska Volcano Observatory (AVO),a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys, has detected unrest at Mount Spurr volcano, located about 125 km west of Anchorage, Alaska, at the northeast end of the Aleutian volcanic arc.This activity consists of increased seismicity melting of the summit ice cap, and substantial rates of C02 and H2S emission.The current unrest is centered beneath the volcano's 3374-m-high summit, whose last known eruption was 5000–6000 years ago. Since then, Crater Peak, 2309 m in elevation and 4 km to the south, has been the active vent. Recent eruptions occurred in 1953 and 1992.

  9. Mount St. Helens and Kilauea volcanoes

    SciTech Connect

    Barrat, J. )

    1989-01-01

    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.

  10. Monitoring eruption activity using temporal stress changes at Mount Ontake volcano

    PubMed Central

    Terakawa, Toshiko; Kato, Aitaro; Yamanaka, Yoshiko; Maeda, Yuta; Horikawa, Shinichiro; Matsuhiro, Kenjiro; Okuda, Takashi

    2016-01-01

    Volcanic activity is often accompanied by many small earthquakes. Earthquake focal mechanisms represent the fault orientation and slip direction, which are influenced by the stress field. Focal mechanisms of volcano-tectonic earthquakes provide information on the state of volcanoes via stresses. Here we demonstrate that quantitative evaluation of temporal stress changes beneath Mt. Ontake, Japan, using the misfit angles of focal mechanism solutions to the regional stress field, is effective for eruption monitoring. The moving average of misfit angles indicates that during the precursory period the local stress field beneath Mt. Ontake was deviated from the regional stress field, presumably by stress perturbations caused by the inflation of magmatic/hydrothermal fluids, which was removed immediately after the expulsion of volcanic ejecta. The deviation of the local stress field can be an indicator of increases in volcanic activity. The proposed method may contribute to the mitigation of volcanic hazards. PMID:26892716

  11. Monitoring eruption activity using temporal stress changes at Mount Ontake volcano.

    PubMed

    Terakawa, Toshiko; Kato, Aitaro; Yamanaka, Yoshiko; Maeda, Yuta; Horikawa, Shinichiro; Matsuhiro, Kenjiro; Okuda, Takashi

    2016-02-19

    Volcanic activity is often accompanied by many small earthquakes. Earthquake focal mechanisms represent the fault orientation and slip direction, which are influenced by the stress field. Focal mechanisms of volcano-tectonic earthquakes provide information on the state of volcanoes via stresses. Here we demonstrate that quantitative evaluation of temporal stress changes beneath Mt. Ontake, Japan, using the misfit angles of focal mechanism solutions to the regional stress field, is effective for eruption monitoring. The moving average of misfit angles indicates that during the precursory period the local stress field beneath Mt. Ontake was deviated from the regional stress field, presumably by stress perturbations caused by the inflation of magmatic/hydrothermal fluids, which was removed immediately after the expulsion of volcanic ejecta. The deviation of the local stress field can be an indicator of increases in volcanic activity. The proposed method may contribute to the mitigation of volcanic hazards.

  12. Volcano hazards in the Mount Jefferson region, Oregon

    USGS Publications Warehouse

    Walder, Joseph S.; Gardner, Cynthia A.; Conrey, Richard M.; Fisher, Bruce J.; Schilling, Steven P.

    1999-01-01

    Mount Jefferson is a prominent feature of the landscape seen from highways east and west of the Cascades. Mount Jefferson (one of thirteen major volcanic centers in the Cascade Range) has erupted repeatedly for hundreds of thousands of years, with its last eruptive episode during the last major glaciation which culminated about 15,000 years ago. Geologic evidence shows that Mount Jefferson is capable of large explosive eruptions. The largest such eruption occurred between 35,000 and 100,000 years ago, and caused ash to fall as far away as the present-day town of Arco in southeast Idaho. Although there has not been an eruption at Mount Jefferson for some time, experience at explosive volcanoes elsewhere suggests that Mount Jefferson cannot be regarded as extinct. If Mount Jefferson erupts again, areas close to the eruptive vent will be severely affected, and even areas tens of kilometers (tens of miles) downstream along river valleys or hundreds of kilometers (hundreds of miles) downwind may be at risk. Numerous small volcanoes occupy the area between Mount Jefferson and Mount Hood to the north, and between Mount Jefferson and the Three Sisters region to the south. These small volcanoes tend not to pose the far-reaching hazards associated with Mount Jefferson, but are nonetheless locally important. A concern at Mount Jefferson, but not at the smaller volcanoes, is the possibility that small to- moderate sized landslides could occur even during periods of no volcanic activity. Such landslides may transform as they move into lahars (watery flows of rock, mud, and debris) that can inundate areas far downstream. The population at immediate risk in the Mount Jefferson region is small, but these residents as well as other people who visit the area for recreation and work purposes should be aware of the potential hazards. Probably the greatest concern in the Mount Jefferson region is the possibility that large lahars might enter reservoirs on either side of the volcano

  13. Mount Erebus activity

    NASA Astrophysics Data System (ADS)

    An international team of scientists reports that unusually high seismic activity joggled Mount Erebus last fall. However, the Antarctic volcano showed no external signs of an eruption.When scientists from the United States, Japan, and New Zealand returned to the world's southernmost active volcano last November for their annual field expedition, they found that seismic stations recorded 650 small tremors on October 8; prior to that, the number of quakes had averaged between 20 and 80 per day. The October 8 maximum was followed by 140 on October 9 and 120 on October 10. Philip R. Kyle, assistant professor of geochemistry at the New Mexico Institute of Mining and Technology in Socorro and leader of the team studying Mount Erebus, noted that some of the strongest earthquakes recorded during the team's 3 years of observations occurred on October 8; these registered less than 2 on the Richter scale.

  14. Active Deformation of Etna Volcano Combing IFSAR and GPS data

    NASA Technical Reports Server (NTRS)

    Lundgren, Paul

    1997-01-01

    The surface deformation of an active volcano is an important indicator of its eruptive state and its hazard potential. Mount Etna volcano in Sicily is a very active volcano with well documented eruption episodes.

  15. Mount St. Helens Volcano, WA, USA

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Mount St. Helens Volcano (46.0N, 122.0W) and its blast zone can be seen in this northeast looking infrared view. Mt. Rainier and Mt. Adams can also be seen in the near area. The Columbia River can be seen at the bottom of the view. When Mt. St. Helens erupted on 18 May 80, the top 1300 ft. disappeared within minutes. The blast area covered an area of more than 150 sq. miles and sent thousands of tons of ash into the upper atmosphere.

  16. Real-Time Data Received from Mount Erebus Volcano, Antarctica

    NASA Astrophysics Data System (ADS)

    Aster, Richard; McIntosh, William; Kyle, Philip; Esser, Richard; Bartel, Beth Ann; Dunbar, Nelia; Johns, Bjorn; Johnson, Jeffrey B.; Karstens, Richard; Kurnik, Chuck; McGowan, Murray; McNamara, Sara; Meertens, Chuck; Pauley, Bruce; Richmond, Matt; Ruiz, Mario

    2004-03-01

    Internal and eruptive volcano processes involve complex interactions of multi-phase fluids with the solid Earth and the atmosphere, and produce diverse geochemical, visible, thermal, elastic, and anelastic effects. Multidisciplinary experimental agendas are increasingly being employed to meet the challenge of understanding active volcanoes and their hazards [e.g., Ripepe et al., 2002; Wallace et al., 2003]. Mount Erebus is a large (3794 m) stratovolcano that forms the centerpiece of Ross Island, Antarctica, the site of the principal U.S. (McMurdo) and New Zealand (Scott) Antarctic bases. With an elevation of 3794 m and a volume of ~1670 km3, Erebus offers exceptional opportunities for extended study of volcano processes because of its persistent, low-level, strombolian activity (Volcano Explosivity Index 0-1) and exposed summit magma reservoir (manifested as a long-lived phonolitic lava lake). Key scientific questions include linking conduit processes to near-field deformations [e.g., Aster et al., 2003], explosion physics [e.g., Johnson et al., 2003], magmatic differentiation and residence [e.g., Kyle et al., 1992], and effects on Antarctic atmospheric and ice geochemistry [e.g., Zreda-Gostynska et al., 1997]. The close proximity of Erebus (35 km) to McMurdo, and its characteristic dry, windy, cold, and high-elevation Antarctic environment, make the volcano a convenient test bed for the general development of volcano surveillance and other instrumentation under extreme conditions.

  17. Snow and ice volume on Mount Spurr Volcano, Alaska, 1981

    USGS Publications Warehouse

    March, Rod S.; Mayo, Lawrence R.; Trabant, Dennis C.

    1997-01-01

    Mount Spurr (3,374 meters altitude) is an active volcano 130 kilometers west of Anchorage, Alaska, with an extensive covering of seasonal and perennial snow, and glaciers. Knowledge of the volume and distribution of snow and ice on a volcano aids in assessing hydrologic hazards such as floods, mudflows, and debris flows. In July 1981, ice thickness was measured at 68 locations on the five main glaciers of Mount Spurr: 64 of these measurements were made using a portable 1.7 megahertz monopulse ice-radar system, and 4 measurements were made using the helicopter altimeter where the glacier bed was exposed by ice avalanching. The distribution of snow and ice derived from these measurements is depicted on contour maps and in tables compiled by altitude and by drainage basins. Basal shear stresses at 20 percent of the measured locations ranged from 200 to 350 kilopascals, which is significantly higher than the 50 to 150 kilopascals commonly referred to in the literature as the 'normal' range for glaciers. Basal shear stresses higher than 'normal' have also been found on steep glaciers on volcanoes in the Cascade Range in the western United States. The area of perennial snow and ice coverage on Mount Spurr was 360 square kilometers in 1981, with an average thickness of 190?50 meters. Seasonal snow increases the volume about 1 percent and increases the area about 30 percent with a maximum in May or June. Runoff from Mount Spurr feeds the Chakachatna River and the Chichantna River (a tributary of the Beluga River). The Chakachatna River drainage contains 14 cubic kilometers of snow and ice and the Chichantna River drainage contains 53 cubic kilometers. The snow and ice volume on the mountain was 67?17 cubic kilometers, approximately 350 times more snow and ice than was on Mount St. Helens before its May 18, 1980, eruption, and 15 times more snow and ice than on Mount Rainier, the most glacierized of the measured volcanoes in the Cascade Range. On the basis of these relative

  18. Ice Volumes on Cascade Volcanoes: Mount Rainier, Mount Hood, Three Sisters, and Mount Shasta

    USGS Publications Warehouse

    Driedger, Carolyn L.; Kennard, Paul M.

    1986-01-01

    During the eruptions of Mount St. Helens the occurrence of floods and mudflows made apparent the need for predictive water-hazard analysis of other Cascade volcanoes. A basic requirement for such analysis is information about the volumes and distributions of snow and ice on other volcanoes. A radar unit contained in a backpack was used to make point measurements of ice thickness on major glaciers of Mount Rainier, Wash.; Mount Hood, Oreg.; the Three Sisters, Oreg.; and Mount Shasta, Calif. The measurements were corrected for slope and were used to develop subglacial contour maps from which glacier volumes were measured. These values were used to develop estimation methods for finding volumes of unmeasured glaciers. These methods require a knowledge of glacier slope, altitude, and area and require an estimation of basal shear stress, each estimate derived by using topographic maps updated by aerial photographs. The estimation methods were found to be accurate within ?20 percent on measured glaciers and to be within ?25 percent when applied to unmeasured glaciers on the Cascade volcanoes. The estimation methods may be applicable to other temperate glaciers in similar climatic settings. Areas and volumes of snow and ice are as follows: Mount Rainier, 991 million ft2, 156 billion ft3; Mount Hood, 145 million ft2, 12 billion ft3; Three Sisters, 89 million ft2, 6 billion ft3; and Mount Shasta, 74 million ft2, 5 billion ft3. The distribution of ice and firn patches within 58 glacierized basins on volcanoes is mapped and listed by altitude and by watershed to facilitate water-hazard analysis.

  19. Volcano hazards in the Mount Hood region, Oregon

    USGS Publications Warehouse

    Scott, W.E.; Pierson, T.C.; Schilling, S.P.; Costa, J.E.; Gardner, C.A.; Vallance, J.W.; Major, J.J.

    1997-01-01

    Mount Hood is a potentially active volcano close to rapidly growing communities and recreation areas. The most likely widespread and hazardous consequence of a future eruption will be for lahars (rapidly moving mudflows) to sweep down the entire length of the Sandy (including the Zigzag) and White River valleys. Lahars can be generated by hot volcanic flows that melt snow and ice or by landslides from the steep upper flanks of the volcano. Structures close to river channels are at greatest risk of being destroyed. The degree of hazard decreases as height above a channel increases, but large lahars can affect areas more than 30 vertical meters (100 vertical feet) above river beds. The probability of eruption-generated lahars affecting the Sandy and White River valleys is 1-in-15 to l-in-30 during the next 30 years, whereas the probability of extensive areas in the Hood River Valley being affected by lahars is about ten times less. The accompanying volcano-hazard-zonation map outlines areas potentially at risk and shows that some areas may be too close for a reasonable chance of escape or survival during an eruption. Future eruptions of Mount Hood could seriously disrupt transportation (air, river, and highway), some municipal water supplies, and hydroelectric power generation and transmission in northwest Oregon and southwest Washington.

  20. Mount Etna: The Anatomy of a Volcano

    NASA Astrophysics Data System (ADS)

    Self, Stephen

    First, let me say that one should be prepared to purchase two copies of this book. The office copy will be permanently on loan to colleagues and students, while the home copy will be yours for enjoyment and reference. This immensely informative book by the British Etna study group, led by John Guest of University College London, will, I am sure, be very popular. It amply fulfills the authors' aims of synthesizing the results of many published and unpublished multinational studies into a coherent picture of Europe's largest and most active volcano.

  1. Seasonality of Shallow Icequakes at Mount Erebus Volcano, Antarctica

    NASA Astrophysics Data System (ADS)

    Knox, H. A.; Aster, R. C.; Kyle, P. R.

    2010-12-01

    Background (non-eruptive) seismicity at Mount Erebus Volcano is dominated by icequake activity on its extensive ice fields and glaciers. We examine icequake seismograms recorded by both long-running and temporary densification deployments spanning seven years (2003-2009) to assess event frequency, size, apparent seasonality, event mechanism, and geographic distribution. In addition to generally investigating mountain glacial ice seismicity in cold and dry glacial environments, we also hope to exploit icequakes as local sources for tomographic imaging of the volcano’s interior in conjunction with 2008-2010 active source and explosive volcanism data. Using Antelope-based methodologies, we determined the distribution and magnitude of a subset of well-recorded icequakes using data from the long-running Mount Erebus Volcano Network (MEVO) network, as well as two dense IRIS PASSCAL supported temporary networks deployed during 2008 and 2009 (the MEVO network consists of six broadband and nine short period stations with environmental data streams; the dense arrays consisted of 24 broadband stations arranged in two concentric rings around the volcano and 99 short period stations deployed near the summit of Erebus volcano and along the Terror-Erebus axis of Ross Island). During each of the seven years, we note a number of large icequake swarms (up to many hundreds of events per day). We hypothesize that many of these events occur in very shallow ice, based on the apparent ambient temperature-driven seasonality of the events. Specifically, approximately 43% of the events occur between March and May and approximately 30% occur between October and December. Each of these times feature rapidly changing ambient air temperatures due to the high latitude appearance/disappearance of the sun. A shallow mechanism is predicted by 1-D thermal skin depth calculations that show that annual temperature fluctuations decay by 1/e within the top few meters of ice.

  2. Mount Meager Volcano, Canada: a Case Study for Landslides on Glaciated Volcanoes

    NASA Astrophysics Data System (ADS)

    Roberti, G. L.; Ward, B. C.; van Wyk de Vries, B.; Falorni, G.; Perotti, L.; Clague, J. J.

    2015-12-01

    Mount Meager is a strato-volcano massif in the Northern Cascade Volcanic Arc (Canada) that erupted in 2350 BP, the most recent in Canada. To study the stability of the Massif an international research project between France ( Blaise Pascal University), Italy (University of Turin) and Canada (Simon Fraser University) and private companies (TRE - sensing the planet) has been created. A complex history of glacial loading and unloading, combined with weak, hydrothermally altered rocks has resulted in a long record of catastrophic landslides. The most recent, in 2010 is the third largest (50 x 106 m3) historical landslide in Canada. Mount Meager is a perfect natural laboratory for gravity and topographic processes such as landslide activity, permafrost and glacial dynamics, erosion, alteration and uplift on volcanoes. Research is aided by a rich archive of aerial photos of the Massif (1940s up to 2006): complete coverage approximately every 10 years. This data set has been processed and multi-temporal, high resolution Orthophoto and DSMs (Digital Surface Models) have been produced. On these digital products, with the support on field work, glacial retreat and landslide activity have been tracked and mapped. This has allowed for the inventory of unstable areas, the identification of lava flows and domes, and the general improvement on the geologic knowledge of the massif. InSAR data have been used to monitor the deformation of the pre-2010 failure slope. It will also be used to monitor other unstable slopes that potentially can evolve to catastrophic collapses of up to 1 km3 in volume, endangering local communities downstream the volcano. Mount Meager is definitively an exceptional site for studying the dynamics of a glaciated, uplifted volcano. The methodologies proposed can be applied to other volcanic areas with high erosion rates such as Alaska, Cascades, and the Andes.

  3. Mount Rainier: living safely with a volcano in your backyard

    USGS Publications Warehouse

    Driedger, Carolyn L.; Scott, William E.

    2008-01-01

    Majestic Mount Rainier soars almost 3 miles (14,410 feet) above sea level and looms over the expanding suburbs of Seattle and Tacoma, Washington. Each year almost two million visitors come to Mount Rainier National Park to admire the volcano and its glaciers, alpine meadows, and forested ridges. However, the volcano's beauty is deceptive - U.S. Geological Survey (USGS) research shows that Mount Rainier is one of our Nation's most dangerous volcanoes. It has been the source of countless eruptions and volcanic mudflows (lahars) that have surged down valleys on its flanks and buried broad areas now densely populated. To help people live more safely with the volcano, USGS scientists are working closely with local communities, emergency managers, and the National Park Service.

  4. Tsunamis generated by eruptions from mount st. Augustine volcano, alaska.

    PubMed

    Kienle, J; Kowalik, Z; Murty, T S

    1987-06-12

    During an eruption of the Alaskan volcano Mount St. Augustine in the spring of 1986, there was concern about the possibility that a tsunami might be generated by the collapse of a portion of the volcano into the shallow water of Cook Inlet. A similar edifice collapse of the volcano and ensuing sea wave occurred during an eruption in 1883. Other sea waves resulting in great loss of life and property have been generated by the eruption of coastal volcanos around the world. Although Mount St. Augustine remained intact during this eruptive cycle, a possible recurrence of the 1883 events spurred a numerical simulation of the 1883 sea wave. This simulation, which yielded a forecast of potential wave heights and travel times, was based on a method that could be applied generally to other coastal volcanos.

  5. Surficial Geologic Map of Mount Veniaminof Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Waythomas, C. F.; Miller, T. P.; Wallace, K.

    2015-12-01

    Mount Veniaminof volcano is a >300 km3 andesite to dacite stratovolcano, characterized by an 8 x 11 km diameter ice-filled summit caldera. Veniaminof is one of the most active volcanoes in the Aleutian arc and has erupted at least 15 times in the past 200 years. The volcano is located on the Alaska Peninsula (56.1979° N, 159.3931° W) about 780 km SW of Anchorage. Our geologic investigations have documented two large (>VEI 5) caldera-forming or -modifying eruptions (V1, V2) of Holocene age whose eruptive products make up most of the surficial deposits around the volcano. These deposits and other unconsolidated glacial, fluvial, and colluvial deposits are depicted on the accompanying map. The the V2 eruption occurred 4.1-4.4 ka (cal 2-sigma age range) and produced an extensive landscape-mantling sequence of pyroclastic deposits >50 km3 in volume that cover or partly obscure older unconsolidated eruptive products. The V1 eruption occurred 8-9 ka and its deposits lie stratigraphically below the pyroclastic deposits associated with the V2 eruption and a prominent, widespread tephra fall deposit erupted from nearby Black Peak volcano 4.4-4.6 ka. The V2 pyroclastic-flow deposits range from densely welded, columnar jointed units exposed along the main valley floors, to loose, unconsolidated, blanketing accumulations of scoriaceous (55-57% SiO2) and lithic material found as far as 75 km from the edifice. Large lahars also formed during the V2 eruption and flowed as far as 50 km from the volcano. The resulting deposits are present in all glacial valleys that head on the volcano and are 10-15 m thick in several locations. Lahar deposits cover an area of about 800-1000 km2, have an approximate volume of 1-2 km3, and record substantial inundation of the major valleys on all flanks of the edifice. Significant amounts of water are required to form lahars of this size, which suggests that an ice-filled summit caldera probably existed when the V2 eruption occurred.

  6. Mount St. Helens and Kilauea volcanoes

    USGS Publications Warehouse

    Barrat, J.

    1989-01-01

    From the south, snow-covered Mount St. Helens looms proudly under a fleecy halo of clouds, rivaling the majestic beauty of neighboring Mount Rainer, Mount Hood, and Mount Adams. Salmon fishermen dot the shores of lakes and streams in the mountain's shadow, trucks loaded with fresh-cut timber barrel down backroads, and deer peer out from stands of tall fir trees. 

  7. Digital Data for Volcano Hazards in the Mount Jefferson Region, Oregon

    USGS Publications Warehouse

    Schilling, S.P.; Doelger, S.; Walder, J.S.; Gardner, C.A.; Conrey, R.M.; Fisher, B.J.

    2008-01-01

    Mount Jefferson has erupted repeatedly for hundreds of thousands of years, with its last eruptive episode during the last major glaciation which culminated about 15,000 years ago. Geologic evidence shows that Mount Jefferson is capable of large explosive eruptions. The largest such eruption occurred between 35,000 and 100,000 years ago. If Mount Jefferson erupts again, areas close to the eruptive vent will be severely affected, and even areas tens of kilometers (tens of miles) downstream along river valleys or hundreds of kilometers (hundreds of miles) downwind may be at risk. Numerous small volcanoes occupy the area between Mount Jefferson and Mount Hood to the north, and between Mount Jefferson and the Three Sisters region to the south. These small volcanoes tend not to pose the far-reaching hazards associated with Mount Jefferson, but are nonetheless locally important. A concern at Mount Jefferson, but not at the smaller volcanoes, is the possibility that small-to-moderate sized landslides could occur even during periods of no volcanic activity. Such landslides may transform as they move into lahars (watery flows of rock, mud, and debris) that can inundate areas far downstream. The geographic information system (GIS) volcano hazard data layer used to produce the Mount Jefferson volcano hazard map in USGS Open-File Report 99-24 (Walder and others, 1999) is included in this data set. Both proximal and distal hazard zones were delineated by scientists at the Cascades Volcano Observatory and depict various volcano hazard areas around the mountain.

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

    USGS Publications Warehouse

    Schilling, Steve P.

    1996-01-01

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

  9. A New Perspective on Mount St. Helens - Dramatic Landform Change and Associated Hazards at the Most Active Volcano in the Cascade Range

    USGS Publications Warehouse

    Ramsey, David W.; Driedger, Carolyn L.; Schilling, Steve P.

    2008-01-01

    Mount St. Helens has erupted more frequently than any other volcano in the Cascade Range during the past 4,000 years. The volcano has exhibited a variety of eruption styles?explosive eruptions of pumice and ash, slow but continuous extrusions of viscous lava, and eruptions of fluid lava. Evidence of the volcano?s older eruptions is recorded in the rocks that build and the deposits that flank the mountain. Eruptions at Mount St. Helens over the past three decades serve as reminders of the powerful geologic forces that are reshaping the landscape of the Pacific Northwest. On May 18, 1980, a massive landslide and catastrophic explosive eruption tore away 2.7 cubic kilometers of the mountain and opened a gaping, north-facing crater. Lahars flowed more than 120 kilometers downstream, destroying bridges, roads, and buildings. Ash from the eruption fell as far away as western South Dakota. Reconstruction of the volcano began almost immediately. Between 1980 and 1986, 80 million cubic meters of viscous lava extruded episodically onto the crater floor, sometimes accompanied by minor explosions and small lahars. A lava dome grew to a height of 267 meters, taller than the highest buildings in the nearby city of Portland, Oregon. Crater Glacier formed in the deeply shaded niche between the 1980-86 lava dome and the south crater wall. Its tongues of ice flowed around the east and west sides of the dome. Between 1989 and 1991, multiple explosions of steam and ash rocked the volcano, possibly a result of infiltrating rainfall being heated in the still-hot interior of the dome and underlying crater floor. In September 2004, rising magma caused earthquake swarms and deformation of the crater floor and glacier, which indicated that Mount St. Helens might erupt again soon. On October 1, 2004, a steam and ash explosion signaled the beginning of a new phase of eruptive activity at the volcano. On October 11, hot rock reached the surface and began building a new lava dome immediately

  10. The 2013 Eruptions of Pavlof and Mount Veniaminof Volcanoes, Alaska

    NASA Astrophysics Data System (ADS)

    Schneider, D. J.; Waythomas, C. F.; Wallace, K.; Haney, M. M.; Fee, D.; Pavolonis, M. J.; Read, C.

    2013-12-01

    Pavlof Volcano and Mount Veniaminof on the Alaska Peninsula erupted during the summer of 2013 and were monitored by the Alaska Volcano Observatory (AVO) using seismic data, satellite and web camera images, a regional infrasound array and observer reports. An overview of the work of the entire AVO staff is presented here. The 2013 eruption of Pavlof Volcano began on May 13 after a brief and subtle period of precursory seismicity. Two volcano-tectonic (VT) earthquakes at depths of 6-8 km on April 24 preceded the onset of the eruption by 3 weeks. Given the low background seismicity at Pavlof, the VTs were likely linked to the ascent of magma. The onset of the eruption was marked by subtle pulsating tremor that coincided with elevated surface temperatures in satellite images. Activity during May and June was characterized by lava fountaining and effusion from a vent near the summit. Seismicity consisted of fluctuating tremor and numerous explosions that were detected on an infrasound array (450 km NE) and as ground-coupled airwaves at local and distant seismic stations (up to 650 km). Emissions of ash and sulfur dioxide were observed in satellite data extending as far as 300 km downwind at altitudes of 5-7 km above sea level. Ash collected in Sand Point (90 km E) were well sorted, 60-150 micron diameter juvenile glass shards, many of which had fluidal forms. Automated objective ash cloud detection and cloud height retrievals from the NOAA volcanic cloud alerting system were used to evaluate the hazard to aviation. A brief reconnaissance of Pavlof in July found that lava flows on the NW flank consist of rubbly, clast rich, 'a'a flows composed of angular blocks of agglutinate and rheomorphic lava. There are at least three overlapping flows, the longest of which extends about 5 km from the vent. Eruptive activity continued through early July, and has since paused or stopped. Historical eruptions of Mount Veniaminof volcano have been from an intracaldera cone within a 10

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

    USGS Publications Warehouse

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

    2001-01-01

    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.

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

    PubMed

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

    2001-02-01

    Hydrothermally altered rocks can weaken volcanoes, increasing the potential for catastrophic sector collapses that can lead to destructive debris flows. Evaluating the hazards associated with such alteration is difficult because alteration has been mapped on few active volcanoes 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 flows and future collapses could threaten areas that are now densely populated. 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 summit. 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.

  13. Operation of a digital seismic network on Mount St. Helens volcano and observations of long-period seismic events that originate under the volcano

    SciTech Connect

    Fehler, M.; Chouet, B.

    1982-01-01

    During the period May through October 1981, a nine station digital seismic array was operated on the flanks of Mount St. Helens volcano in the state of Washington. The purpose was to obtain high quality digital seismic data from a dense seismic array operating near and in the summit crater of the volcano to facilitate study of near field seismic waveforms generated under the volcano. Our goal is to investigate the source mechanism of volcanic tremor and seismic activity associated with magma intrusion, dome growth and steam-ash emissions occurring within the crater of Mount St. Helens.

  14. Digital Data for Volcano Hazards from Mount Rainier, Washington, Revised 1998

    USGS Publications Warehouse

    Schilling, S.P.; Doelger, S.; Hoblitt, R.P.; Walder, J.S.; Driedger, C.L.; Scott, K.M.; Pringle, P.T.; Vallance, J.W.

    2008-01-01

    Mount Rainier at 4393 meters (14,410 feet) is the highest peak in the Cascade Range; a dormant volcano having glacier ice that exceeds that of any other mountain in the conterminous United States. This tremendous mass of rock and ice, in combination with great topographic relief, poses a variety of geologic hazards, both during inevitable future eruptions and during the intervening periods of repose. The volcano's past behavior is the best guide to possible future hazards. The written history (about A.D. 1820) of Mount Rainier includes one or two small eruptions, several small debris avalanches, and many small lahars (debris flows originating on a volcano). In addition, prehistoric deposits record the types, magnitudes, and frequencies of other events, and areas that were affected. Mount Rainier deposits produced since the latest ice age (approximately during the past 10,000 years) are well preserved. Studies of these deposits indicate we should anticipate potential hazards in the future. Some phenomena only occur during eruptions such as tephra falls, pyroclastic flows and surges, ballistic projectiles, and lava flows while others may occur without eruptive activity such as debris avalanches, lahars, and floods. The five geographic information system (GIS) volcano hazard data layers used to produce the Mount Rainier volcano hazard map in USGS Open-File Report 98-428 (Hoblitt and others, 1998) are included in this data set. Case 1, case 2, and case 3 layers were delineated by scientists at the Cascades Volcano Observatory and depict various lahar innundation zones around the mountain. Two additional layers delineate areas that may be affected by post-lahar sedimentation (postlahar layer) and pyroclastic flows (pyroclastic layer).

  15. Managing public and media response to a reawakening volcano: lessons from the 2004 eruptive activity of Mount St. Helens: Chapter 23 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Frenzen, Peter M.; Matarrese, Michael T.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    Volcanic eruptions and other infrequent, large-scale natural disturbances pose challenges and opportunities for public-land managers. In the days and weeks preceding an eruption, there can be considerable uncertainty surrounding the magnitude and areal extent of eruptive effects. At the same time, public and media interest in viewing developing events is high and concern for public safety on the part of local land managers and public safety officials is elevated. Land managers and collaborating Federal, State, and local officials must decide whether evacuations or restrictions to public access are necessary, the appropriate level of advance preparation, and how best to coordinate between overlapping jurisdictions. In the absence of a formal Federal or State emergency declaration, there is generally no identified source of supplemental funding for emergency-response preparation or managing extraordinary public and media response to developing events. In this chapter, we examine responses to escalating events that preceded the 2004 Mount St. Helens eruption and changes in public perception during the extended period of the largely nonexplosive, dome-building eruption that followed. Lessons learned include the importance of maintaining up-to-date emergency-response plans, cultivating close working relationships with collaborating agencies, and utilizing an organized response framework that incorporates clearly defined roles and responsibilities and effective communication strategies.

  16. Volcanoes!

    USGS Publications Warehouse

    ,

    1997-01-01

    Volcanoes is an interdisciplinary set of materials for grades 4-8. Through the story of the 1980 eruption of Mount St. Helens, students will answer fundamental questions about volcanoes: "What is a volcano?" "Where do volcanoes occur and why?" "What are the effects of volcanoes on the Earth system?" "What are the risks and the benefits of living near volcanoes?" "Can scientists forecast volcanic eruptions?"

  17. Volcano Monitoring with Coda Wave Interferometry at Mount Erebus, Antarctica

    NASA Astrophysics Data System (ADS)

    Gret, A.; Snieder, R.; Aster, R.

    2003-12-01

    Multiply-scattered waves dominate the late seismic coda. Small changes in the medium that would have no detectable influence on the first arrivals can be highly amplified by multiple scattering and readily observed in the coda. We apply coda wave interferometry to monitor subsurface temporal changes at Mount Erebus Volcano, Ross Island, Antarctica. Erebus is one of the few volcanoes known to have an open conduit system hosting a persistent convecting lava lake. Strombolian eruptions, caused by the explosive decompression of large bubbles of exsolved volatiles disrupt the lake itself, which subsequently refills within a few minutes. Because of the recoverability of this system, these eruptions provide a repeatable seismic source of seismic waves for sampling the strongly scattering volcano. Repeating eruption seismograms have been recorded at fixed station sites over several years, and the coda is seen to be highly reproducible over extended periods of time. We find waveform correlation coefficients as high as 0.98 for short-period seismograms recorded up to several days apart. However, in comparing seismograms separated by approximately a month, we note a small decrease in correlation. Furthermore, we see a much larger decorrelation of the waveforms spanning a time period of one or even two years. Coda energy is thus providing information on systematic source and/or subsurface changes.

  18. Deposits of large volcanic debris avalanches at Mount St. Helens and Mount Shasta volcanoes

    SciTech Connect

    Glicken, H.

    1985-01-01

    Large volcanic debris avalanches are among the world's largest mass movements. The rockslide-debris avalanche of the May 18, 1980, eruption of Mount St. Helens produced a 2.8 km/sup 3/ deposit and is the largest historic mass movement. A Pleistocene debris avalanche at Mount Shasta produced a 26 km/sup 3/ deposit that may be the largest Quaternary mass movement. The hummocky deposits at both volcanoes consist of rubble divided into (1) block facies that comprises unconsolidated pieces of the old edifice transported relatively intact, and (2) matrix facies that comprises a mixture of rocks from the old mountain and material picked up from the surrounding terrain. At Mount St. Helens, the juvenile dacite is found in the matrix facies, indicating that matrix facies formed from explosions of the erupting magma as well as from disaggregation and mixing of blocks. The block facies forms both hummocks and interhummock areas in the proximal part of the St. Helens avalanche deposit. At Mount St. Helens, the density of the old cone is 21% greater than the density of the avalanche deposit. Block size decreases with distance. Clast size, measured in the field and by sieving, coverages about a mean with distance, which suggests that blocks disaggregated and mixed together during transport.

  19. Observations of volcanic tremor at Mount St. Helens volcano

    SciTech Connect

    Fehler, M.

    1983-04-10

    Digital recordings of ground motion during tremor episodes accompanying eruptions at Mount St. Helens Volcano in the state of Washington on August 7 and October 16-18, 1980, are studied. The spectra of the vertical component waveforms contain at least two dominant peaks at 1.0 and 1.3 Hz for all events recorded during both eruptions that were studied. Spectra of horizontal ground motion show peaks at 0.9 and 1.1 Hz. The relative amplitude of the two peaks changes between tremor episodes and during single tremor episodes and shows no consistent relation to amplitude of ground motion. Spectra of long-period earthquakes are very similar to those of tremor events, suggesting that tremor is composed of many long-period earthquakes that occur over a period of time. The unique waveform of tremor events observed at Mount St. Helens must be due to a source effect, since the relative amplitude of the two dominant peaks changes during tremor episodes. The path effect on tremor waveforms is small since there are no peaks in the spectra of waveforms recorded during tectonic earthquakes occurring in the vicinity of Mount S. Helens. The consistency of the location of the spectral peaks for the wide range of tremor amplitudes means that there must be a physical length at the source that is constant, independent of the amplitude of motion at the source. Amplitude of ground motion varies between 0.11 and 4.7 ..mu..m. Seismic moment rates during the two eruptions are found to vary between 6 x 10/sup 18/ and 1 x 10/sup 20/ dynes cm/s. Study of tremor amplitudes recorded at Corvallis, Oregon, leads to the conclusion that tremor accompanying the cataclysmic May 18, 1980, eruption was at least one order of magnitude larger in amplitude than tremor during August and October.

  20. Springs, streams, and gas vent on and near Mount Adams volcano, Washington

    USGS Publications Warehouse

    Nathenson, Manuel; Mariner, Robert H.

    2013-01-01

    Springs and some streams on Mount Adams volcano have been sampled for chemistry and light stable isotopes of water. Spring temperatures are generally cooler than air temperatures from weather stations at the same elevation. Spring chemistry generally reflects weathering of volcanic rock from dissolved carbon dioxide. Water in some springs and streams has either dissolved hydrothermal minerals or has reacted with them to add sulfate to the water. Some samples appear to have obtained their sulfate from dissolution of gypsum while some probably involve reaction with sulfide minerals such as pyrite. Light stable isotope data for water from springs follow a local meteoric water line, and the variation of isotopes with elevation indicate that some springs have very local recharge and others have water from elevations a few hundred meters higher. No evidence was found for thermal or slightly thermal springs on Mount Adams. A sample from a seeping gas vent on Mount Adams was at ambient temperature, but the gas is similar to that found on other Cascade volcanoes. Helium isotopes are 4.4 times the value in air, indicating that there is a significant component of mantle helium. The lack of fumaroles on Mount Adams and the ambient temperature of the gas indicates that the gas is from a hydrothermal system that is no longer active.

  1. Space Radar Image of Mount Pinatubo Volcano, Philippines

    NASA Technical Reports Server (NTRS)

    1994-01-01

    These are color composite radar images showing the area around Mount Pinatubo in the Philippines. The images were acquired by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on April 14, 1994 (left image) and October 5,1994 (right image). The images are centered at about 15 degrees north latitude and 120.5 degrees east longitude. Both images were obtained with the same viewing geometry. The color composites were made by displaying the L-band (horizontally transmitted and received) in red; the L-band (horizontally transmitted and vertically received) in green; and the C-band (horizontally transmitted and vertically received) in blue. The area shown is approximately 40 kilometers by 65 kilometers (25 miles by 40 miles). The main volcanic crater on Mount Pinatubo produced by the June 1991 eruptions and the steep slopes on the upper flanks of the volcano are easily seen in these images. Red on the high slopes shows the distribution of the ash deposited during the 1991 eruption, which appears red because of the low cross-polarized radar returns at C and L bands. The dark drainages radiating away from the summit are the smooth mudflows, which even three years after the eruptions continue to flood the river valleys after heavy rain. Comparing the two images shows that significant changes have occurred in the intervening five months along the Pasig-Potrero rivers (the dark area in the lower right of the images). Mudflows, called 'lahars,' that occurred during the 1994 monsoon season filled the river valleys, allowing the lahars to spread over the surrounding countryside. Three weeks before the second image was obtained, devastating lahars more than doubled the area affected in the Pasig-Potrero rivers, which is clearly visible as the increase in dark area on the lower right of the images. Migration of deposition to the east (right) has affected many communities. Newly affected areas included the community

  2. Renewed Seismic Unrest at Mount Spurr Volcano, Alaska in 2004: Evidence for a Magmatic Intrusion

    NASA Astrophysics Data System (ADS)

    Power, J. A.; Stihler, S. D.; Dixon, J. P.; Moran, S. C.; Caplan-Auerbach, J.; Prejean, S. G.; McGee, K.; Doukas, M. P.; Roman, D. C.

    2004-12-01

    In early July 2004 the Alaska Volcano Observatory (AVO) detected a pronounced increase in seismic activity beneath the summit of Mount Spurr volcano that continues at present. From 1 July through 31 August 2004, AVO located 1094 Volcano-Tectonic (VT) earthquakes and 177 Long-Period (LP) events within 12 km of the volcano's summit, although many events classified as VT contained mixed frequencies. The largest event has a magnitude of 1.6 and hypocentral depths generally range from 0 to 5 km below sea-level. The cumulative seismic moment for July - August 2004 is 5x10**13 Nm. Focal mechanisms of located events in July and August 2004 are dominated by normal faulting, which is consistent with what has been observed beneath the summit since 1984. This seismicity rate is the highest observed at Mount Spurr since the conclusion of the 1992 eruption sequence. Seismicity in 2004 differs markedly from that observed prior to the eruptions in 1992 in that almost all hypocenters are concentrated beneath the volcano's summit vent and not the historically active Crater Peak vent, site of eruptions in 1953 and 1992. Analysis of AVO earthquake catalogs suggests anomalous seismicity may have begun as early as 20 October 2002 with a prominent swarm of 60 VT earthquakes (Mmax = 2.4) located roughly 2 km west of the volcano's summit. Smaller increases in the shallow seismicity rates were also noted between July and November 2003 and beginning in February 2004. These events ranged in depth between 0 and 4 km below sea-level. A subtle increase of deep LP events was also detected beginning in July 2003 and peaking in June 2004, immediately prior to the onset of strong shallow seismicity. These events concentrate about 4 km to the southeast of Crater Peak, generally range in depth from 20 to 35 km and occur at a rate of 2 to 4 located events per month. Associated with the 2004 seismic activity AVO has also observed anomalous melting and disruption of the summit ice cap that began in late

  3. Active submarine volcano sampled

    USGS Publications Warehouse

    Taylor, B.

    1983-01-01

    On June 4, 1982, two full dredge hauls of fresh lava were recovered from the upper flanks of Kavachi submarine volcano, Solomon Islands, in the western Pacific Ocean, from the water depths of 1,200 and 2,700 feet. the shallower dredge site was within 0.5 mile of the active submarine vent shown at the surface by an area of slick water, probably caused by gas emissions. Kavachi is a composite stratovolcano that has been observed to erupt every year or two for at least the last 30 years (see photographs). An island formed in 1952, 1961, 1965, and 1978; but, in each case, it rapidly eroded below sea level. The latest eruption was observed by Solair pilots during the several weeks up to and including May 18, 1982. 

  4. Monitoring active volcanoes

    USGS Publications Warehouse

    Tilling, Robert I.

    1987-01-01

    One of the most spectacular, awesomely beautiful, and at times destructive displays of natural energy is an erupting volcano, belching fume and ash thousands of meters into the atmosphere and pouring out red-hot molten lava in fountains and streams. Countless eruptions in the geologic past have produced volcanic rocks that form much of the Earth's present surface. The gradual disintegration and weathering of these rocks have yielded some of the richest farmlands in the world, and these fertile soils play a significant role in sustaining our large and growing population. Were it not for volcanic activity, the Hawaiian Islands with their sugar cane and pineapple fields and magnificent landscapes and seascapes would not exist to support their residents and to charm their visitors. Yet, the actual eruptive processes are catastrophic and can claim life and property.

  5. Scattering matrices of volcanic ash particles of Mount St. Helens, Redoubt, and Mount Spurr Volcanoes

    NASA Astrophysics Data System (ADS)

    MuñOz, O.; Volten, H.; Hovenier, J. W.; Veihelmann, B.; van der Zande, W. J.; Waters, L. B. F. M.; Rose, W. I.

    2004-08-01

    We present measurements of the whole scattering matrix as a function of the scattering angle at a wavelength of 632.8 nm in the scattering angle range 3°-174° of randomly oriented particles taken from seven samples of volcanic ashes corresponding to four different volcanic eruptions: the 18 May 1980 Mount St. Helens eruption, the 1989-1990 Redoubt eruption, and the 18 August and 17 September 1992 Mount Spurr eruptions. The samples were collected at different distances from the vent. The samples studied contain large mass fractions of fine particles and were chosen to represent ash that could remain in the atmosphere for at least hours or days. They include fine ashfall samples that fell at a variety of distances from the volcano and pyroclastic flows that retained their fine fractions. Together, they represent a range of ashes likely to remain in the atmosphere in volcanic clouds following eruptions from convergent plate boundary volcanoes, Earth's most important group of explosive sources of ash. All measured scattering matrix elements are confined to rather limited domains when plotted as functions of the scattering angle following the general trends presented by irregular mineral particles. This similarity in the scattering behavior justifies the construction of an average scattering matrix for volcanic ash particles as a function of the scattering angle. To facilitate the use of the average scattering matrix for multiple-scattering calculations with polarization included, we present a synthetic scattering matrix based on the average scattering matrix for volcanic ashes and the assumption that the diffraction forward scattering peak is the same for randomly oriented nonspherical particles and projected-surface-area-equivalent spheres. This synthetic scattering matrix is normalized so that the average of its 1-1 element over all directions equals unity. It is available in the full range from 0° to 180° and can be used, for example, for interpretation of

  6. Headless Debris Flows From Mount Spurr Volcano, Alaska

    NASA Astrophysics Data System (ADS)

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

    2004-12-01

    Sometime between June 20 and July 15, 2004-and contemporaneous with an increase of seismicity beneath the volcano, and elevated gas emissions-a sudden release of impounded water from the summit area of Mt. Spurr volcano produced about a dozen separate debris flow lobes emanating from crevasses and bergschrunds in the surface ice several hundred meters down the east-southeast flank from the summit. These debris flows were first observed by AVO staff on a July 15 overflight and appeared to represent a single flooding event; subsequent snow cover and limited accessibility have prevented direct investigation of these deposits. Observed from the air, they are dark, elongate lobate deposits, up to several hundred meters long and tens of meters wide, draping the steep (up to ~45 degree) slopes and cascading over and into crevasses. A water-rich phase from the flows continued down slope of the termini of several lobate deposits, eroding linear rills into the snow and ice down slope. We infer that the dark material composing these flows is likely remobilized coarse lapilli from the June 1992 tephra fall produced by an eruption of Crater Peak, a satellite vent of Mt. Spurr located 3.5 km to the south. Between 1 and 2 meters of basaltic andesite tephra fell directly on the Spurr summit during the 1992 eruption. The exact mechanism for sudden release of water-laden remobilized tephra flows from the summit basin is not clear. However, observations in early August, 2004, of an 80 m x 110-m-wide pit in the summit area snow and ice suggest the possibility of a partial roof collapse of a summit meltwater basin, likely associated with subglacial melting due to recent heat flux. Such a collapse could have led to the hydraulic surge of meltwater, and rapid mixing with tephra to produce slurries. These slurries traveled down slope beneath the ice surface to emerge through existing crevasses and other easy points of exit on the steep inclines. Mount Spurr is an ice- and snow covered

  7. Living with a volcano in your backyard: an educator's guide with emphasis on Mount Rainier

    USGS Publications Warehouse

    Driedger, Carolyn L.; Doherty, Anne; Dixon, Cheryl; Faust, Lisa M.

    2005-01-01

    The National Park Service and the U.S. Geological Survey’s Volcano Hazards Program (USGS-VHP) support development and publication of this educator’s guide as part of their mission to educate the public about volcanoes. The USGS-VHP studies the dynamics of volcanoes, investigates eruption histories, develops hazard assessments, monitors volcano-related activity, and collaborates with local officials to lower the risk of disruption when volcanoes become restless.

  8. Very long period oscillations of Mount Erebus Volcano

    NASA Astrophysics Data System (ADS)

    Aster, R.; Mah, S.; Kyle, P.; McIntosh, W.; Dunbar, N.; Johnson, J.; Ruiz, M.; McNamara, S.

    2003-11-01

    The exposed top of the conduit system at Mount Erebus Volcano, Ross Island, Antarctica, is a convecting lava (magma) lake hosting Strombolian eruptions caused by the explosive decompression of large (up to 5 m radius) gas slugs. Short-period (SP; f ≥1 Hz) seismoacoustic eruption seismograms are accompanied by oscillatory very long period (VLP) signals observed in the near field by broadband seismometers 0.7 to 2.5 km from the lava lake. A variable VLP onset, preceding eruptions by several seconds, is followed by a repeatable VLP coda that persists for several minutes until the lava lake recovers to its preeruptive level. VLP signals are dominated by distinct decaying nonharmonic modes, the largest at periods of 20.7, 11.3, and 7.8 s, with respective source Q values of approximately 11, 18, and 4. Particle motions indicate a temporally evolving source producing increasingly vertical posteruptive displacements as the signal decays. VLP scalar moments, up to ˜5×1011 N m, exceed SP moments by an order of magnitude or more, suggesting distinct, though genetically related, SP and VLP source mechanisms. We conclude that VLP signals arise from excitation of a quasi-linear resonator that is intimately associated with the conduit system and is excited by gravity and inertial forces associated with gas slug ascent, eruption, and magma recharge. VLP signal stability across hundreds of eruptions spanning 5 years, the persistence of the lava lake, and the rapid posteruptive lava lake recovery indicate a stable near-summit magma reservoir and VLP source process.

  9. Digital Data for Volcano Hazards of the Mount Hood Region, Oregon

    USGS Publications Warehouse

    Schilling, S.P.; Doelger, S.; Scott, W.E.; Pierson, T.C.; Costa, J.E.; Gardner, C.A.; Vallance, J.W.; Major, J.J.

    2008-01-01

    Snow-clad Mount Hood dominates the Cascade skyline from the Portland metropolitan area to the wheat fields of Wasco and Sherman Counties. The mountain contributes valuable water, scenic, and recreational resources that help sustain the agricultural and tourist segments of the economies of surrounding cities and counties. Mount Hood is also one of the major volcanoes of the Cascade Range, having erupted repeatedly for hundreds of thousands of years, most recently during two episodes in the past 1,500 yr. The last episode ended shortly before the arrival of Lewis and Clark in 1805. When Mount Hood erupts again, it will severely affect areas on its flanks and far downstream in the major river valleys that head on the volcano. Volcanic ash may fall on areas up to several hundred kilometers downwind. The purpose of the volcano hazard report USGS Open-File Report 97-89 (Scott and others, 1997) is to describe the kinds of hazardous geologic events that have happened at Mount Hood in the past and to show which areas will be at risk when such events occur in the future. This data release contains the geographic information system (GIS) data layers used to produce the Mount Hood volcano hazard map in USGS Open-File Report 97-89. Both proximal and distal hazard zones were delineated by scientists at the Cascades Volcano Observatory and depict various volcano hazard areas around the mountain. A second data layer contains points that indicate estimated travel times of lahars.

  10. Spectral measurements of HCl in the plume of the Antarctic Volcano Mount Erebus

    NASA Astrophysics Data System (ADS)

    Keys, J. G.; Wood, S. W.; Jones, N. B.; Murcray, F. J.

    A favourable combination of circumstances on 7 September 1996 allowed tracking of the sun through the plume of the active Antarctic volcano, Mount Erebus (77.5°S, 167.2°E, height 3794m). Fourier transform spectrometer (FTS) measurements were therefore possible from the Arrival Heights laboratory (77.8°S, 166.7°E), located approximately 30km south of the volcano. FTS scans were made with the interferometer looking upwind and downwind of the summit, resulting in spectra of HCl which showed large column enhancements of the gas when the sun was viewed through the volcanic plume. Pressure broadened spectra confirm that this enhancement was due to an additional tropospheric component in the column. Assumptions have been made of the plume dimensions and velocity, and a daily downwind flux of HCl derived. This is compared with the daily average flux emitted at the volcanic crater source during periods of passive outgassing, as derived from measurements using other techniques. The result suggests that for this quiescent type of emission from the volcano there is no evidence of rapid tropospheric scavenging of HCl, as might be expected for more explosive events and a less dry atmosphere.

  11. Springs, streams, and gas vent on and near Mount Adams volcano, Washington

    NASA Astrophysics Data System (ADS)

    Nathenson, M.; Mariner, R. H.

    2013-12-01

    air, indicating that there is a significant component of mantle helium. The lack of fumaroles on Mount Adams and the ambient temperature of the gas indicate that the gas is from a hydrothermal system that is no longer active. This is surprising, given the evidence for intense hydrothermal activity in the past. Of the major Cascade volcanoes, Mount Adams is the only one with no evidence for present hydrothermal discharge (Ingebritsen and Mariner, 2010). Ingebritsen, S.E., and Mariner, R.H., 2010, Hydrothermal heat discharge in the Cascade Range, northwestern United States: Journal of Volcanology and Geothermal Research, v. 196, p. 208-218. Nathenson, Manuel, and Mariner, R.H., 2013, Springs, streams, and gas vent on and near Mount Adams volcano, Washington: U.S. Geological Survey Scientific Investigations Report 2013-5097, 19 p., [Available on the Web at http://pubs.usgs.gov/sir/2013/5097/.

  12. Volcano-tectonic deformation at Mount Shasta and Medicine Lake volcanoes, northern California, from GPS: 1996-2004

    NASA Astrophysics Data System (ADS)

    Lisowski, M.; Poland, M.; Dzurisin, D.; Owen, S.

    2004-12-01

    Mount Shasta and Medicine Lake volcanoes are two of the three Cascade volcanoes targeted for dense GPS and strainmeter deployments by the magmatic systems component of Earthscope's Plate Boundary Observatory (PBO). Leveling surveys indicate an average subsidence rate of ˜9 mm/yr at Medicine Lake volcano since at least 1954, which could result from draining of a magma reservoir, cooling/crystallization of a subsurface body of magma or hot rock, loading by the volcano and dense intrusions, crustal thinning due to regional extension, or some combination of these mechanisms. Displacements from GPS surveys in 1996 and 1999 revealed regional block rotation and contraction across the summit of the volcano, but the time interval was too short to distinguish between possible mechanisms. On Mount Shasta, a 21-line, 12-km aperture EDM network was measured in 1981, 1982, and 1984 with no significant deformation detected, nor was there significant length change in three EDM lines recovered with GPS in 2000. We present results from GPS surveys completed in June and July 2004 of the region surrounding both Mount Shasta and Medicine Lake volcanoes. We find regional deformation to be dominated by a block rotation about a pole in southeast Oregon, similar to but generally south of poles determined by other workers using GPS in western Oregon and Washington. No significant residual deformation remains in the four GPS stations located on Mount Shasta, which were previously measured in 2000. In contrast, GPS results from six stations on the upper flanks of Medicine Lake volcano confirm the known subsidence and are consistent with elastic half-space models of volume loss that fit the leveling data. No significant residual regional strain was detected. As a result, we believe that subsidence at Medicine Lake does not likely result from crustal thinning due to regional extension. A more detailed examination of Medicine Lake subsidence sources, Mount Shasta edifice deformation, and

  13. Seismic activity of Erebus volcano, antarctica

    NASA Astrophysics Data System (ADS)

    Kaminuma, Katsutada

    1987-11-01

    Mount Erebus is presently the only Antarctic volcano with sustained eruptive activity in the past few years. It is located on Ross Island and a convecting anorthoclase phonolite lava lake has occupied the summit crater of Mount Erebus from January 1973 to September 1984. A program to monitor the seismic activity of Mount Erebus named IMESS was started in December 1980 as an international cooperative program among Japan, the United States and New Zealand. A new volcanic episode began on 13 September, 1984 and continued until December. Our main observations from the seismic activity from 1982 1985 are as follows: (1) The average numbers of earthquakes which occurred around Mount Erebus in 1982, 1983 and January August 1984 were 64, 134 and 146 events per day, respectively. Several earthquake swarms occurred each year. (2) The averag number of earthquakes in 1985 is 23 events per day, with only one earthquake swarm. (3) A remarkable decrease of the background seismicity is recognized before and after the September 1984 activity. (4) Only a few earthquakes were located in the area surrounding Erebus mountain after the September 1984 activity. A magma reservoir is estimated to be located in the southwest area beneath the Erebus summit, based on the hypocenter distributions of earthquakes.

  14. Special issue: The changing shapes of active volcanoes: Recent results and advances in volcano geodesy

    USGS Publications Warehouse

    Poland, Michael P.; Newman, Andrew V.

    2006-01-01

    The 18 papers herein report on new geodetic data that offer valuable insights into eruptive activity and magma transport; they present new models and modeling strategies that have the potential to greatly increase understanding of magmatic, hydrothermal, and volcano-tectonic processes; and they describe innovative techniques for collecting geodetic measurements from remote, poorly accessible, or hazardous volcanoes. To provide a proper context for these studies, we offer a short review of the evolution of volcano geodesy, as well as a case study that highlights recent advances in the field by comparing the geodetic response to recent eruptive episodes at Mount St. Helens. Finally, we point out a few areas that continue to challenge the volcano geodesy community, some of which are addressed by the papers that follow and which undoubtedly will be the focus of future research for years to come.

  15. Geologic map of the Valdez D-1 and D-2 quadrangles (Mount Wrangell Volcano), Alaska

    USGS Publications Warehouse

    Richter, D.H.; McGimsey, R.G.; Labay, K.A.; Lanphere, M.A.; Moore, R.B.; Nye, C.J.; Rosenkrans, D.S.; Winkler, G.R.

    2016-04-29

    This study was directed toward Mount Wrangell volcano and the older Wrangell volcanic field rocks that underlie the volcano. These older lavas include the Chetaslina lavas (867 ka–1,650 ka) and a basaltic andesite–dacite center (1,590 ka–1,640 ka) whose source areas are not well defined. Older Paleozoic and Mesozoic sedimentary, igneous, and metamorphic rocks of the Wrangellia terrane underlie the entire Wrangell volcanic field.

  16. Eruptive history and petrology of Mount Drum volcano, Wrangell Mountains, Alaska

    USGS Publications Warehouse

    Richter, D.H.; Moll-Stalcup, E. J.; Miller, T.P.; Lanphere, M.A.; Dalrymple, G.B.; Smith, R.L.

    1994-01-01

    Mount Drum is one of the youngest volcanoes in the subduction-related Wrangell volcanic field (80x200 km) of southcentral Alaska. It lies at the northwest end of a series of large, andesite-dominated shield volcanoes that show a northwesterly progression of age from 26 Ma near the Alaska-Yukon border to about 0.2 Ma at Mount Drum. The volcano was constructed between 750 and 250 ka during at least two cycles of cone building and ring-dome emplacement and was partially destroyed by violent explosive activity probably after 250 ka. Cone lavas range from basaltic andesite to dacite in composition; ring-domes are dacite to rhyolite. The last constructional activity occured in the vicinity of Snider Peak, on the south flank of the volcano, where extensive dacite flows and a dacite dome erupted at about 250 ka. The climactic explosive eruption, that destroyed the top and a part of the south flank of the volcano, produced more than 7 km3 of proximal hot and cold avalanche deposits and distal mudflows. The Mount Drum rocks have medium-K, calc-alkaline affinities and are generally plagioclase phyric. Silica contents range from 55.8 to 74.0 wt%, with a compositional gap between 66.8 and 72.8 wt%. All the rocks are enriched in alkali elements and depleted in Ta relative to the LREE, typical of volcanic arc rocks, but have higher MgO contents at a given SiO2, than typical orogenic medium-K andesites. Strontium-isotope ratios vary from 0.70292 to 0.70353. The compositional range of Mount Drum lavas is best explained by a combination of diverse parental magmas, magma mixing, and fractionation. The small, but significant, range in 87Sr/86Sr ratios in the basaltic andesites and the wide range of incompatible-element ratios exhibited by the basaltic andesites and andesites suggests the presence of compositionally diverse parent magmas. The lavas show abundant petrographic evidence of magma mixing, such as bimodal phenocryst size, resorbed phenocrysts, reaction rims, and

  17. Eruptive history and petrology of Mount Drum volcano, Wrangell Mountains, Alaska

    NASA Astrophysics Data System (ADS)

    Richter, D. H.; Moll-Stalcup, E. J.; Miller, T. P.; Lanphere, M. A.; Dalrymple, G. B.; Smith, R. L.

    1994-03-01

    Mount Drum is one of the youngest volcanoes in the subduction-related Wrangell volcanic field (80×200 km) of southcentral Alaska. It lies at the northwest end of a series of large, andesite-dominated shield volcanoes that show a northwesterly progression of age from 26 Ma near the Alaska-Yukon border to about 0.2 Ma at Mount Drum. The volcano was constructed between 750 and 250 ka during at least two cycles of cone building and ring-dome emplacement and was partially destroyed by violent explosive activity probably after 250 ka. Cone lavas range from basaltic andesite to dacite in composition; ring-domes are dacite to rhyolite. The last constructional activity occurred in the vicinity of Snider Peak, on the south flank of the volcano, where extensive dacite flows and a dacite dome erupted at about 250 ka. The climactic explosive eruption, that destroyed the top and a part of the south flank of the volcano, produced more than 7 km3 of proximal hot and cold avalanche deposits and distal mudflows. The Mount Drum rocks have medium-K, calc-alkaline affinities and are generally plagioclase phyric. Silica contents range from 55.8 to 74.0 wt%, with a compositional gap between 66.8 and 72.8 wt%. All the rocks are enriched in alkali elements and depleted in Ta relative to the LREE, typical of volcanic arc rocks, but have higher MgO contents at a given SiO2, than typical orogenic medium-K andesites. Strontium-isotope ratios vary from 0.70292 to 0.70353. The compositional range of Mount Drum lavas is best explained by a combination of diverse parental magmas, magma mixing, and fractionation. The small, but significant, range in 87Sr/86Sr ratios in the basaltic andesites and the wide range of incompatible-element ratios exhibited by the basaltic andesites and andesites suggests the presence of compositionally diverse parent magmas. The lavas show abundant petrographic evidence of magma mixing, such as bimodal phenocryst size, resorbed phenocrysts, reaction rims, and

  18. Volcanoes.

    ERIC Educational Resources Information Center

    Tilling, Robert I.

    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…

  19. Eruptions of Mount Erebus Volcano Constrained with Infrasound, Video, and Doppler Radar

    NASA Astrophysics Data System (ADS)

    Johnson, J. B.; Jones, K. R.; Aster, R.; Kyle, P.; McIntosh, W.; Gerst, A.

    2008-12-01

    Co-eruptive infrasound recorded within several km of volcanoes can provide effective constraints on atmospheric accelerations or momentum exchange in the vicinity of active volcanic vents. These atmospheric perturbations can be induced by impulsive gas injection into the atmosphere (i.e., eruptive explosions), by deflection of a solid or fluid lava surface, or through a superposition of these effects. The "simple" lava lake bubble-bursting eruptions of Mount Erebus Volcano (Antarctica) provide an ideal test bed for multi- disciplinary observations of volcanic infrasound because of proximal (within few hundred meters) deployment of microphones and line-of-sight viewing geometry of cameras and radar to the vent. Erebus video observations provide timing constraints on the infrasound generation mechanisms, which include both pre- eruptive distension of the lava lake surface and gas expansion and jetting following large explosive bubble bursts. Network infrasound recordings are used to quantify the time history of explosive gas flux and cumulative yield (>103 kg of gas in ~0.5 s), which is corroborated by the video and Doppler radar observations. Infrasound records from a three-station network also show azimuthal variations, which can be attributed to non-isotropic components of the acoustic wavefield radiated during eruption. We model Erebus gas bubble bursts as a combination of symmetric gas expansion (monopole source) and gas jetting (dipole source) and corroborate this explosive asymmetry with video and Doppler radar observations.

  20. Changes in Seismic Velocity During the 2004 - 2008 Eruption of Mount St. Helens Volcano

    NASA Astrophysics Data System (ADS)

    Hotovec-Ellis, A. J.; Vidale, J. E.; Gomberg, J. S.; Moran, S. C.; Thelen, W. A.

    2013-12-01

    Mount St. Helens (MSH) effusively erupted in late 2004, following an 18-year quiescence. Many swarms of repeating earthquakes accompanied the extrusion and in some cases the waveforms from these earthquakes evolved slowly, possibly reflecting changes in the properties of the volcano that affect seismic wave propagation. We use coda-wave interferometry to quantify these changes in terms of small (usually <1%) changes in seismic velocity structure by determining how relatively condensed or stretched the coda is between two similar earthquakes. We then utilize several hundred distinct families of repeating earthquakes at once to create a continuous function of velocity change observed at any station in the seismic network. The rate of earthquakes allows us to track these changes on a daily or even hourly time scale. Following years of no seismic velocity changes larger than those due to climatic processes (tenths of a percent), we observed decreases in seismic velocity of >1% coincident with the onset of increased earthquake activity beginning September 23, 2004. These changes are largest near the summit of the volcano, and likely related to shallow deformation as magma first worked its way to the surface. Changes in velocity are often attributed to deformation, especially volumetric strain and the opening or closing of cracks, but also with nonlinear responses to ground shaking and fluid intrusion. We compare velocity changes across the eruption with other available observations, such as deformation (e.g., GPS, tilt, photogrammetry), to better constrain the relationships between velocity change and its possible causes.

  1. Gas geothermometry for typical and atypical hydrothermal gases: A case study of Mount Mageik and Trident Volcanoes, Alaska

    NASA Astrophysics Data System (ADS)

    Taryn, Lopez; Tassi, Franco; Capecchiacci, Francesco; Chiodini, Giovanni; Fiebig, Jens; Rizzo, Andrea; Caliro, Stefano

    2016-04-01

    The chemical and isotopic composition of volcanic gases can be used to detect subsurface magma, qualitatively constrain magma degassing depth, evaluate temperature and pressure conditions of hydrothermal reservoirs, and constrain volatile sources, all of which are important for volcano monitoring, eruption forecasting and hazard mitigation. Two persistently degassing and seismically active volcanoes from the Katmai Volcanic Complex, Alaska, were targeted during this study to characterize subvolcanic conditions. Fumarole and steam condensate samples were collected for chemical and isotopic analysis from Mount Mageik and Trident Volcanoes in July 2013. These volcanoes are located within 10 km of each other, both show evidence for active hydrothermal systems, and both have boiling point temperature fumaroles, yet emit notably different gas compositions. Mount Mageik's gases are composed primarily of H20, CO2, H2S, and N2, with minor CH4, CO and H2 and negligible HCl amounts, reflecting a typical "hydrothermal" gas composition. Although, Trident's gases are somewhat similar in composition to those of Mount Mageik, they show several unusual features for hydrothermal fluids, most notably extremely high concentrations of reduced gas species. Specifically, the H2/H2O values are ≈1 log-unit lower (i.e. more reducing) than those produced by the rock redox buffers commonly dominating in a hydrothermal environment. These anomalous ratios are accompanied by relatively high concentrations high-temperature (CO, and H2S), and low temperature (CH4) gases, suggesting a strong chemical disequilibrium and/or chemical-physical conditions far from those typically acting on hydrothermal fluids. Additionally, when δ13C ratios of methane, ethane and propane are considered, a deviation from the expected "hydrothermal" carbon number trend is observed for Trident volcano, suggesting an "abiogenic reversal". Gas geothermometry in the H2O-CO2-H2-CO-CH4 system provides estimated temperatures

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

    USGS Publications Warehouse

    Poland, Michael P.; Hamburger, Michael W.; Newman, Andrew V.

    2006-01-01

    At the very heart of volcanology lies the search for the 'plumbing systems' that form the inner workings of Earth’s active volcanoes. By their very nature, however, the magmatic reservoirs and conduits that underlie these active volcanic systems are elusive; mostly they are observable only through circumstantial evidence, using indirect, and often ambiguous, surficial measurements. Of course, we can infer much about these systems from geologic investigation of materials brought to the surface by eruptions and of the exposed roots of ancient volcanoes. But how can we study the magmatic processes that are occurring beneath Earth’s active volcanoes? What are the geometry, scale, physical, and chemical characteristics of magma reservoirs? Can we infer the dynamics of magma transport? Can we use this information to better forecast the future behavior of volcanoes? These questions comprise some of the most fundamental, recurring themes of modern research in volcanology. The field of volcano geodesy is uniquely situated to provide critical observational constraints on these problems. For the past decade, armed with a new array of technological innovations, equipped with powerful computers, and prepared with new analytical tools, volcano geodesists have been poised to make significant advances in our fundamental understanding of the behavior of active volcanic systems. The purpose of this volume is to highlight some of these recent advances, particularly in the collection and interpretation of geodetic data from actively deforming volcanoes. The 18 papers that follow report on new geodetic data that offer valuable insights into eruptive activity and magma transport; they present new models and modeling strategies that have the potential to greatly increase understanding of magmatic, hydrothermal, and volcano-tectonic processes; and they describe innovative techniques for collecting geodetic measurements from remote, poorly accessible, or hazardous volcanoes. To provide

  3. Catastrophic debris avalanche from ancestral Mount Shasta volcano, California

    NASA Astrophysics Data System (ADS)

    Crandell, D. R.; Miller, C. D.; Glicken, H. X.; Christiansen, R. L.; Newhall, C. G.

    1984-03-01

    A debris-avalanche deposit extends 43 km northwestward from the base of Mount Shasta across the floor of Shasta Valley, California, where it covers an area of at least 450 km2. The surface of the deposit is dotted with hundreds of mounds, hills, and ridges, all formed of blocks of pyroxene andesite and unconsolidated volcaniclastic deposits derived from an ancestral Mount Shasta. Individual hills are separated by flat-topped laharlike deposits that also form the matrix of the debris avalanche and slope northwestward about 5 m/km. Radiometric ages of rocks in the deposit and of a postavalanche basalt flow indicate that the avalanche occurred between about 300,000 and 360,000 yr ago. An inferred average thickness of the deposit, plus a computed volume of about 4 km3 for the hills and ridges, indicate an estimated volume of about 26 km3, making it the largest known Quaternary landslide on Earth.

  4. Potential hazards from future eruptions in the vicinity of Mount Shasta Volcano, Northern California

    USGS Publications Warehouse

    Miller, C. Dan

    1980-01-01

    Mount Shasta has erupted, on the average, at least once per 800 years during the last 10,000 years, and about once per 600 years during the last 4,500 years. The last known eruption occurred about 200 radiocarbon years ago. Eruptions during the last 10,000 years produced lava flows and domes on and around the flanks of Mount Shasta, and pyroclastic flows from summit and flank vents extended as far as 20 kilometers from the summit. Most of these eruptions also produced large mudflows, many of which reached more than several tens of kilometers from Mount Shasta. Future eruptions like those of the past could endanger the communities of Weed, Mount Shasta, McCloud, and Dunsmuir, located at or near the base of Mount Shasta. Such eruptions will most likely produce deposits of lithic ash, lava flows, domes, and pyroclastic flows. Lava flows and pyroclastic flows may affect low-and flat-lying ground almost anywhere within about 20 kilometers of the summit of Mount Shasta, and mudflows may cover valley floors and other low areas as much as several tens of kilometers from the volcano. On the basis of its past behavior, Mount Shasta is not likely to erupt large volumes of pumiceous ash in the future; areas subject to the greatest risk from air-fall tephra are located mainly east and within about 50 kilometers of the summit of the volcano. The degree of risk from air-fall tephra decreases progressively as the distance from the volcano increases.

  5. The eruption of Mount Pagan volcano, Mariana Islands, 15 May 1981

    USGS Publications Warehouse

    Banks, N.G.; Koyanagi, R.Y.; Sinton, J.M.; Honma, K.T.

    1984-01-01

    A major explosive eruption occurred 15 May 1981 at Mount Pagan Volcano, the larger of two historic eruptive centers on Pagan Island, Mariana Islands. The eruption was preceded by increased numbers of locally felt earthquakes beginning in late March or early April and by new ground cracks, new sublimates, and increased gas emissions. A swarm of felt earthquakes began at 0745h (local time = UCT+10 hours) 15 May, and at 0915 h, closely following a loud sonic boom, a strong plinian column issued from the volcano. The high-altitude ash cloud (at least 13.5 km) travelled south-southeast, but ash and scoria deposits were thickest (> 2 m) in the NW sector of the island because of the prevailing low-altitude southeasterly winds. The early activity of 15 May probably involved magmatic eruption along a fissure system oriented about N10??E. However, the eruption became hydromagmatic, possibly within minutes, and was largely restricted to three long-lived vents. The northernmost of these built a substantial new scoria-ash cinder cone. Flows and air-fall deposits, consisting almost entirely of juvenile material, exceeded 105 ?? 106 m3 in volume (75 ?? 106 m3 of magma) on land and at least 70-100 ?? 606 m3 at sea. An unknown volume was carried away by stratospheric winds. Lithic blocks and juvenile bombs as large as 1 m in diameter were thrown more than 2 km from the summit, and evidence for base-surge was observed in restricted corridors as low as 200 m elevation on the north and south slopes of the volcano. Neither of these events resulted in serious injuries to the 54 residents of the island, nor did the eruption produce serious chemical hazards in their water supply. Weak eruptions occurred during the ensuing month, and some of these were monitored by ground observations, seismic monitoring, and deformation studies. Precursory seismicity and possibly deformation occurred with some of the observed eruptions. More vigorous eruptions were reported by visiting residents in late

  6. (abstract) Mount Rainier: New Remote Sensing Observations of a Decade Volcano

    NASA Technical Reports Server (NTRS)

    Realmuto, V. J.; Zebker, H. A.; Frank, D.

    1994-01-01

    Mount Rainier was selected as a Decade Volcano by the International Association of Volcanology and Chemistry of the Earth's Interior. The purpose of this selection is to focus scientific and public attention on Mount Rainier during the current decade, the United Nations-designated International Decade of Natural Hazard Reduction. The Mount Rainier science plan calls for remote sensing surveys to monitor the volcano. To date, we have conducted airborne surveys with visible and near-infrared, thermal infrared, and interferometric radar instruments. Our preliminary analysis of some night-time time-series thermal infrared survey data sets of the summit suggests that, aside from seasonal variations in snow cover, there have been no qualitative changes in the size or pattern of the summit hot spots. Day-time airborne surveys were done to record the current surface appearance of the volcano and map hydrothermal alteration in the summit region. An interferometric radar survey yielded a high-resolution digital elevation model (DEM) which serves as a base for the registration of the other remote sensing data sets. More importantly, the DEM documents the current topography of glaciers and valleys. Planned biannual radar survey of mount rainier will produce a data set from which seasonal changes in glacier and valley topography can be characterized. Such characterization is essential if we are to recognize geothermally induced changes in snow and ice cover.

  7. Peralkaline volcanism in a continental collisional setting: Mount Nemrut volcano, Eastern Anatolia

    NASA Astrophysics Data System (ADS)

    Çubukçu, H. E.; Ulusoy, I.; Aydar, E.; Sen, E.; Ersoy, O.; Gourgaud, A.

    2012-04-01

    Quaternary Mount Nemrut is an active volcano in the Eastern Anatolia which culminates at 2948 m and having an elliptic summit caldera with 8.5 x 7 km diameter. The volcano is situated on the east of the deformed and dissected remnant of the Muş-Van ramp basin located at the northern foot of the Bitlis-Zagros suture zone. The suture zone is the southern margin of the continental collision between Arabian and Anatolian plates. The continental collision along the Bitlis-Zagros suture zone commenced in the Middle Miocene following the closure of the southern segment of Neo-Tethys ocean and the subduction of northern margin of Arabian plate beneath Anatolian plate. Upon the collision and the uplift of the region, widespread volcanism, which exhibits varying eruption styles and geochemical characteristics, affected most of the Eastern Anatolia. The intracontinental convergence and N - S directed compressional - contractional tectonic regime remained till the end of Late Miocene. However, compressional - extensional regime became dominant in the Early-Late Pliocene. Following the slab break off, asthenosphere beneath the Arabian Foreland probably have migrated towards the slab window, which was opened during the detachment, and invaded the mantle wedge beneath East Anatolian Collision zone. Volcanism is still active in the region, represented by major Quaternary volcanic centers. The magmatic characteristics of Nemrut volcano is appealingly distinct compared to the other Quaternary volcanic centers in the region. The overall geochemical and mineralogical affinity of Nemrut volcanism exhibits strong similarities with the well-known sites of continental intra-plate extension. The volcano has distinguishing features of a typical silica oversaturated peralkaline (molecular ratio (Na + K / Al)>1) suite: (a) The volcanic products vary from transitional olivine basalt to peralkaline rhyolite (abundant comendite and scarce pantellerite) (b) Predominance by erupted volume of

  8. Volcanoes

    USGS Publications Warehouse

    Tilling, Robert I.

    1998-01-01

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

  9. The Mount Manengouba, a complex volcano of the Cameroon Line: Volcanic history, petrological and geochemical features

    NASA Astrophysics Data System (ADS)

    Pouclet, André; Kagou Dongmo, Armand; Bardintzeff, Jacques-Marie; Wandji, Pierre; Chakam Tagheu, Pulchérie; Nkouathio, David; Bellon, Hervé; Ruffet, Gilles

    2014-09-01

    The volcanic story of Mount Manengouba is related to four chronological stages: (1) forming of the early Manengouba shield volcano between 1.55 and 0.94 Ma, (2) building of the Eboga strato-cone between 0.94 and 0.89 Ma, (3) caldera collapse and silicic extrusions of the Elengoum Complex between 0.89 and 0.70 Ma, and (4) intra-caldera and flank activity between 0.45 and 0.11 Ma. The volume of the volcano is calculated at 320 km3 ± 5%. The volcanic rocks are attributed to two magmatic outputs. The first and main magma generation produced the shield volcano, the strato-cone, and the syn- to post-caldera extrusions, displaying a complete series from basanites to trachytes (magmatic Group 1). The second magma generation is limited to the late and flank activity evolving from basanites to trachy-phonolite (magmatic Group 2). Both magmatic groups belong to the under-saturated alkaline sodic series. Petrological calculations locate the magmatic reservoir between 37 and 39 km in the upper mantle for the Group 1 lavas, and between 42 and 44 km for the Group 2 lavas. Trachytes were generated in a secondary crustal reservoir. Magmatic series evolve with medium to low pressure fractional crystallization of olivine, pyroxene, oxides, feldspar, and apatite. Significant crustal assimilation is evidenced in trachytes. The magma of Group 1 was generated with 3-6% of partial melting of a moderately enriched source containing 3-7% of garnet. Melting took place in the spinel to garnet transition zone located at 70-90 km and around 25 kb. The magma of Group 2 resulted from a slightly higher partial melting from a less garnet-rich source that indicates uprising of the melting column in the upper part of transition zone. Sr, Nd, and Pb isotope data of the Manengouba rocks and neighboring lavas are analyzed and compared with those of the mafic lavas of the CVL. Three source components are distinguished: a depleted component originated from the asthenospheric swell, a radiogenic component

  10. Hydrologic consequences of hot-rock/snowpack interactions at Mount St. Helens Volcano, Washington

    USGS Publications Warehouse

    Pierson, Thomas C.

    1999-01-01

    Emplacement of hot volcanic debris onto a thick snowpack can trigger hazardous rapid flows of sediment (including ice grains) and water, which can travel far beyond the flanks of a volcano. Five papers in this volume document aspects of rapid-snowmelt events that occurred in Mount St. Helens between 1982 and 1984; one paper offers a theoretical explanation of features present at depositional contacts between hot rock and snow.

  11. ASTER-SRTM Perspective of Mount Oyama Volcano, Miyake-Jima Island, Japan

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Mount Oyama is a 820-meter-high (2,700 feet) volcano on the island of Miyake-Jima, Japan. In late June 2000, a series of earthquakes alerted scientists to possible volcanic activity. On June 27, authorities evacuated 2,600 people, and on July 8 the volcano began erupting and erupted five times over that week. The dark gray blanket covering green vegetation in the image is the ash deposited by prevailing northeasterly winds between July 8 and 17. This island is about 180 kilometers (110 miles) south of Tokyo and is part of the Izu chain of volcanic islands that runs south from the main Japanese island of Honshu. Miyake-Jima is home to 3,800 people. The previous major eruptions of Mount Oyama occurred in 1983 and 1962, when lava flows destroyed hundreds of houses. An earlier eruption in 1940 killed 11 people.

    This image is a perspective view created by combining image data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) aboard NASA's Terra satellite with an elevation model from the Shuttle Radar Topography Mission (SRTM). Vertical relief is exaggerated, and the image includes cosmetic adjustments to clouds and image color to enhance clarity of terrain features.

    The ASTER instrument is a cooperative project between NASA, JPL, and the Japanese Ministry of International Trade and Industry.

    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 three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the

  12. Preliminary Geologic Map of Mount Pagan Volcano, Pagan Island, Commonwealth of the Northern Mariana Islands

    USGS Publications Warehouse

    Trusdell, Frank A.; Moore, Richard B.; Sako, Maurice K.

    2006-01-01

    Pagan Island is the subaerial portion of two adjoining Quaternary stratovolcanoes near the middle of the active Mariana Arc, [FAT1]north of Saipan. Pagan and the other volcanic islands that constitute part of the Arc form the northern half of the East Mariana Ridge[FAT2], which extends about 2-4 km above the ocean floor. The > 6-km-deep Mariana Trench adjoins the East Mariana Ridge on the east, and the Mariana Trough, partly filled with young lava flows and volcaniclastic sediment, lies on the west of the Northern Mariana Islands (East Mariana Ridge. The submarine West Mariana Ridge, Tertiary in age, bounds the western side of the Mariana Trough. The Mariana Trench and Northern Mariana Islands (East Mariana Ridge) overlie an active subduction zone where the Pacific Plate, moving northwest at about 10.3 cm/year, is passing beneath the Philippine Plate, moving west-northwest at 6.8 cm/year. Beneath the Northern Mariana Islands, earthquake hypocenters at depths of 50-250 km identify the location of the west-dipping subduction zone, which farther west becomes nearly vertical and extends to 700 km depth. During the past century, more than 40 earthquakes of magnitude 6.5-8.1 have shaken the Mariana Trench. The Mariana Islands form two sub-parallel, concentric, concave-west arcs. The southern islands comprise the outer arc and extend north from Guam to Farallon de Medinilla. They consist of Eocene to Miocene volcanic rocks and uplifted Tertiary and Quaternary limestone. The nine northern islands extend from Anatahan to Farallon de Pajaros and form part of the inner arc. The active inner arc extends south from Anatahan, where volcanoes, some of which are active, form seamounts west of the older outer arc. Other volcanic seamounts of the active arc surmount the East Mariana Ridge in the vicinity of Anatahan and Sarigan and north and south of Farallon de Pajaros. Six volcanoes (Farallon de Pajaros, Asuncion, Agrigan, Mount Pagan, Guguan, and Anatahan) in the northern islands

  13. Linking petrology and seismology at an active volcano.

    PubMed

    Saunders, Kate; Blundy, Jon; Dohmen, Ralf; Cashman, Kathy

    2012-05-25

    Many active volcanoes exhibit changes in seismicity, ground deformation, and gas emissions, which in some instances arise from magma movement in the crust before eruption. An enduring challenge in volcano monitoring is interpreting signs of unrest in terms of the causal subterranean magmatic processes. We examined over 300 zoned orthopyroxene crystals from the 1980-1986 eruption of Mount St. Helens that record pulsatory intrusions of new magma and volatiles into an existing larger reservoir before the eruption occurred. Diffusion chronometry applied to orthopyroxene crystal rims shows that episodes of magma intrusion correlate temporally with recorded seismicity, providing evidence that some seismic events are related to magma intrusion. These time scales are commensurate with monitoring signals at restless volcanoes, thus improving our ability to forecast volcanic eruptions by using petrology.

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

    NASA Astrophysics Data System (ADS)

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

    2007-05-01

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

  15. Volcano collapse promoted by hydrothermal alteration and edifice shape, Mount Rainier, Washington

    USGS Publications Warehouse

    Reid, M.E.; Sisson, T.W.; Brien, D.L.

    2001-01-01

    Catastrophic collapses of steep volcano flanks threaten many populated regions, and understanding factors that promote collapse could save lives and property. Large collapses of hydrothermally altered parts of Mount Rainier have generated far-traveled debris flows; future flows would threaten densely populated parts of the Puget Sound region. We evaluate edifice collapse hazards at Mount Rainier using a new three-dimensional slope stability method incorporating detailed geologic mapping and subsurface geophysical imaging to determine distributions of strong (fresh) and weak (altered) rock. Quantitative three-dimensional slope stability calculations reveal that sizeable flank collapse (>0.1 km3) is promoted by voluminous, weak, hydrothermally altered rock situated high on steep slopes. These conditions exist only on Mount Rainier's upper west slope, consistent with the Holocene debris-flow history. Widespread alteration on lower flanks or concealed in regions of gentle slope high on the edifice does not greatly facilitate collapse. Our quantitative stability assessment method can also provide useful hazard predictions using reconnaissance geologic information and is a potentially rapid and inexpensive new tool for aiding volcano hazard assessments.

  16. Electrical activity during the 2006 Mount St. Augustine volcanic eruptions

    USGS Publications Warehouse

    Thomas, Ronald J.; Krehbiel, Paul R.; Rison, William; Edens, H. E.; Aulich, G. D.; McNutt, S.R.; Tytgat, Guy; Clark, E.

    2007-01-01

    By using a combination of radio frequency time-of-arrival and interferometer measurements, we observed a sequence of lightning and electrical activity during one of Mount St. Augustine's eruptions. The observations indicate that the electrical activity had two modes or phases. First, there was an explosive phase in which the ejecta from the explosion appeared to be highly charged upon exiting the volcano, resulting in numerous apparently disorganized discharges and some simple lightning. The net charge exiting the volcano appears to have been positive. The second phase, which followed the most energetic explosion, produced conventional-type discharges that occurred within plume. Although the plume cloud was undoubtedly charged as a result of the explosion itself, the fact that the lightning onset was delayed and continued after and well downwind of the eruption indicates that in situ charging of some kind was occurring, presumably similar in some respects to that which occurs in normal thunderstorms.

  17. Partners in International Research and Education: Student Contributions to the Collaborative Investigation of Bezymianny, Shiveluch, and Karymsky Volcanoes, Kamchatka, Russia and Mount St. Helens, WA, USA.

    NASA Astrophysics Data System (ADS)

    Shipman, J. S.; Kayzar, T. M.; Team, P.

    2008-12-01

    Undergraduate and graduate students as well as senior researchers from the U.S., Russia, and Japan are investigating volcanism as participants of the National Science Foundation initiative Partners in International Research and Education (PIRE). The goal of this study is to use the benefits of global comparisons to increase our understanding of explosive volcanism while at the same time developing international collaboration between scientists in the U.S., Russia, and Japan. International collaboration is established through field work in Kamchatka, Russia investigating the active systems of Bezymianny, Shiveluch, and Karymsky volcanoes with a specific focus on historic collapse-blast type eruptions. The Kamchatka volcanic arc provides unique access to multiple active volcanic systems that can be compared and contrasted to the well-studied behavior at Mount St. Helens, WA., USA. Conversely, Mount St. Helens also provides a field setting for Russian and Japanese students to be incorporated in U.S. research. Student participants employ their respective techniques in geochemistry, geophysics, petrology, and remote sensing to study the eruption response of Bezymianny and Shiveluch volcanoes, which have experienced edifice collapse. During the 2008 field season, the increased activity at Bezymianny volcano shortened a planned field expedition. In order to preserve the integrity of the program and provide a safer environment for researchers, alternative field studies began at Karymsky volcano. In July, an anonymously large eruption at Karymsky volcano permitted the collection of unique real-time data of the eruptive event. Here we present student research from three field seasons in the Kamchatka volcanic arc and associated workshops at Mount St. Helens, WA. Results include estimates of magma storage depth, gas emissions measurements, evidence for dynamic thermal regime changes in fresh volcanic deposits, and data constraining magma inputs and sources at each volcano. By

  18. Using An Extensive Catalogue of Repeatable Strombolian Eruptions to Monitor Small Medium Changes at Mount Erebus Volcano, Antarctica

    NASA Astrophysics Data System (ADS)

    Henderson, B.; Aster, R. C.; Kyle, P.

    2005-12-01

    A recent study by Gret et al. (2005) reconfirmed earlier work demonstrating remarkable, though variable, repeatability of short-period seismic signals produced by characteristic Strombolian eruptions of Mount Erebus. The eruptions originate as impulsive explosions of large simple gas bubbles from the surface of a long-lived, actively convecting phonolitic lava lake that rapidly refills afterwards. This self-reconstructing eruptive system lends itself to highly repeatable seismic sources. Gret et al. further noted that these repeatable seismograms (extending many 10s of seconds into the coda) and associated seismic energy scattered within the low-velocity waveguide of the volcano conduit might facilitate the novel tracking of small temporal changes in seismic velocity and/or impedance contrast within the near summit magma body and more general conduit system. We expand on this suggestive work using comprehensive correlation-based similar seismogram analysis of an extensive database of over 3000 candidate Strombolian eruptions occurring between Jan 1992 and July 2005, and recorded at up to 9 different seismic stations situated around the volcano. To obviate potential complications caused by nonlinear response (e.g., clipping) at short-period instruments, we incorporate data from broadband, high-dynamic range sensors and digital telemetry installed since 2001, and take advantage of a new period of prolific eruptions, especially since early 2005, Gret, A., Snieder, R., Aster, R., Kyle, P., Monitoring rapid temporal change in a volcano with coda wave interferometry, Geop. Res. Lett., 32, L06304, doi:10.1029/2004GL021143, 2005.

  19. Swarms of repeating stick-slip icequakes triggered by snow loading at Mount Rainier volcano

    NASA Astrophysics Data System (ADS)

    Allstadt, Kate; Malone, Stephen D.

    2014-05-01

    We have detected over 150,000 small (M < 1) low-frequency (~1-5 Hz) repeating earthquakes over the past decade at Mount Rainier volcano, most of which were previously undetected. They are located high (>3000 m) on the glacier-covered edifice and occur primarily in weeklong to monthlong swarms composed of simultaneous distinct families of events. Each family contains up to thousands of earthquakes repeating at regular intervals as often as every few minutes. Mixed polarity first motions, a linear relationship between recurrence interval and event size, and strong correlation between swarm activity and snowfall suggest the source is stick-slip basal sliding of glaciers. The sudden added weight of snow during winter storms triggers a temporary change from smooth aseismic sliding to seismic stick-slip sliding in locations where basal conditions are favorable to frictional instability. Coda wave interferometry shows that source locations migrate over time at glacial speeds, starting out fast and slowing down over time, indicating a sudden increase in sliding velocity triggers the transition to stick-slip sliding. We propose a hypothesis that this increase is caused by the redistribution of basal fluids rather than direct loading because of a 1-2 day lag between snow loading and earthquake activity. This behavior is specific to winter months because it requires the inefficient drainage of a distributed subglacial drainage system. Identification of the source of these frequent signals offers a view of basal glacier processes, discriminates against alarming volcanic noises, documents short-term effects of weather on the cryosphere, and has implications for repeating earthquakes, in general.

  20. Dry tilt network at Mount Rainier, Washington

    USGS Publications Warehouse

    Dzurisin, Daniel; Johnson, Daniel J.; Symonds, R.B.

    1984-01-01

    In addition to its primary responsibility of monitoring active Mount St. Helens, the David A. Johnston Cascades Volcano Observatory (CVO) has been charged with obtaining baseline geodetic and geochemical information at each of the other potentially active Cascade volcanoes. Dry tilt and/or trilateration networks were established during 1975-82 at Mount Baker, Mount St. Helens, Mount Hood, Mount Shasta, Lassen Peak, Crater Lake, and Long Valley caldera; coverage was extended during September 1982 to include Mount Rainier.

  1. Predicting and validating the motion of an ash cloud during the 2006 eruption of Mount Augustine volcano

    USGS Publications Warehouse

    Collins, Richard L.; Fochesatto, Javier; Sassen, Kenneth; Webley, Peter W.; Atkinson, David E.; Dean, Kenneson G.; Cahill, Catherine F.; Mizutani, Kohei

    2007-01-01

    On 11 January 2006, Mount Augustine volcano in southern Alaska began erupting after 20- year repose. The Anchorage Forecast Office of the National Weather Service (NWS) issued an advisory on 28 January for Kodiak City. On 31 January, Alaska Airlines cancelled all flights to and from Anchorage after multiple advisories from the NWS for Anchorage and the surrounding region. The Alaska Volcano Observatory (AVO) had reported the onset of the continuous eruption. AVO monitors the approximately 100 active volcanoes in the Northern Pacific. Ash clouds from these volcanoes can cause serious damage to an aircraft and pose a serious threat to the local communities, and to transcontinental air traffic throughout the Arctic and sub-Arctic region. Within AVO, a dispersion model has been developed to track the dispersion of volcanic ash clouds. The model, Puff, was used operational by AVO during the Augustine eruptive period. Here, we examine the dispersion of a volcanic ash (or aerosol) cloud from Mount Augustine across Alaska from 29 January through the 2 February 2006. We present the synoptic meteorology, the Puff predictions, and measurements from aerosol samplers, laser radar (or lidar) systems, and satellites. Aerosol samplers revealed the presence of volcanic aerosols at the surface at sites where Puff predicted the ash clouds movement. Remote sensing satellite data showed the development of the ash cloud in close proximity to the volcano consistent with the Puff predictions. Two lidars showed the presence of volcanic aerosol with consistent characteristics aloft over Alaska and were capable of detecting the aerosol, even in the presence of scattered clouds and where the ash cloud is too thin/disperse to be detected by remote sensing satellite data. The lidar measurements revealed the different trajectories of ash consistent with the Puff predictions. Dispersion models provide a forecast of volcanic ash cloud movement that might be undetectable by any other means but are

  2. Application of photogrammetry to the study of volcano-glacier interactions on Mount Wrangell, Alaska

    NASA Technical Reports Server (NTRS)

    Benson, C. S.; Follett, A. B.

    1986-01-01

    Most Alaskan volcanoes are glacier covered and provide excellent opportunities to study interactions between glaciers and volcanoes. The present paper is concerned with such a study, taking into account the Mt. Wrangell (4317 m) which is the northernmost active volcano (solfatara activity) on the Pacific Rim (62 deg N; 144 deg W). While the first photographs on the summit of Mt. Wrangell were published more than 75 years ago, research there began in 1953 and 1954. Satellite images reveal activity at the summit of Mt. Wrangell. However, the resolution is not sufficient for conducting important measurements regarding ice volume losses. For this reason, vertical aerial photographs of the summit were obtained, and a field trip to the summit was conducted. Aspects of photogrammetry are discussed, taking into account questions of ground control, aerial photography, topographic mapping, digital cross sections, and orthophotos.

  3. Crystallization Processes and Magma Chamber Dynamics at the Mount Erebus Volcano Lava Lake: The Mineralogic Message

    NASA Astrophysics Data System (ADS)

    Kelly, P. J.; Kyle, P. R.; Dunbar, N. W.

    2006-12-01

    Mount Erebus volcano, Antarctica, hosts a persistently convecting and degassing lake of crystal-rich (30-40 vol.% phenocrysts) phonolite magma, providing a direct view into an active, stable, upper-level magma chamber. Mineral phases in lava bombs ejected by small strombolian eruptions from the lava lake between 1972 and 2004 were examined. Detailed compositional profiles of Ti-magnetite and large (up to 10 cm) anorthoclase feldspar phenocrysts were obtained by electron microprobe (EMP). The EMP data provide insight into the controls on crystallization in the lava lake/shallow magmatic system as well as the processes occurring in the magma chamber. Ti-magnetite are uniform and unzoned. The anorthoclase are complexly compositionally zoned over a restricted range (An10.3-22.9Ab62.8-68.1Or11.4-27.2) and contain abundant melt inclusions (up to ~30 vol. %). Coupled, inverse variations of An and Or account for ~96% of major element compositional variability and independent Ab variations account for ~4%. The anorthoclase compositions and textures suggest crystallization proceeds at low degrees of effective undercooling and is controlled by decompression-induced degassing of water. Unlike microlites that form during a single episode of ascent and eruption, the anorthoclase phenocrysts record multiple episodes of decompression and rim growth due to shallow convection in the lava lake under variable PH2O conditions. Crystals contained within a single lava bomb do not have shared crystallization histories, suggesting that differential movement of crystals and melt occurs within the magma chamber and that lava bombs are a mechanical assembly of crystals brought together a short time before or during an eruption. Large temperature variations at the surface of the lava lake (~400°C) are not reflected in the crystal compositions. Apparently, the kinetics of mineral growth are too sluggish to record the transient cooling (estimated to be ~20 mins.) experienced by crystals at the

  4. A Volcano Rekindled: The Renewed Eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    Mount St. Helens began a dome-building eruption in September 2004 after nearly two decades of quiescence. Dome growth was initially robust, became more sluggish with time, and ceased completely in late January 2008. The volcano has been quiet again since January 2008. Professional Paper 1750 describes the first 1 1/2 years of this eruptive activity, chiefly from September 2004 until December 2005. Its 37 chapters contain contributions of 87 authors from 23 institutions, including the U.S. Geological Survey, Forest Service, many universities, and local and State emergency management agencies. Chapter topics range widely - from seismology, geology, geodesy, gas geochemistry, and petrology to the human endeavor required for managing the public volcanic lands and distributing information during the hectic early days of a renewed eruption. In PDF format, the book may be downloaded in its entirety or by its topical sections, each section including a few prefatory paragraphs that describe the general findings, recurrent themes, and, in some cases, the unanswered questions that arise repeatedly. Those readers who prefer downloading the smaller files of only a chapter or two have this option available as well. Readers are directed to chapter 1 for a general overview of the eruption and the manner in which different chapters build our knowledge of events. More detailed summaries for specific topics can be found in chapter 2 (seismology), chapter 9 (geology), chapter 14 (deformation), chapter 26 (gas geochemistry), and chapter 30 (petrology). The printed version of the book may be purchased as a hardback weighty tome (856 printed pages) that includes a DVD replete with the complete online version, including all chapters and several additional appendixes not in the printed book.

  5. Swarms of repeating stick-slip glacierquakes triggered by snow loading at Mount Rainier volcano

    NASA Astrophysics Data System (ADS)

    Allstadt, K.; Malone, S. D.; Shean, D. E.; Fahnestock, M. A.; Vidale, J. E.

    2013-12-01

    We have detected over 150,000 low-frequency (~1-5 Hz) repeating earthquakes over the past decade at Mount Rainier volcano by scanning continuous seismic data from the permanent seismic network. Most of these were previously undetected due to their small size (M<1), shallow locations, and emergent waveforms. The earthquakes are located high (>3000 m) on the glacier-covered part of the edifice. They occur primarily in week- to month-long swarms of activity that strongly correlate with precipitation, namely snowfall, with a lag of about 1-2 days. Furthermore, there is a linear relationship between inter-event repeat time and the size of the subsequent event - consistent with slip-predictable stick-slip behavior. This pattern suggests that the additional load imparted by the sudden added weight of snow during winter storms triggers a temporary change from smooth aseismic sliding to seismic stick-slip basal sliding in locations where basal conditions are close to frictional instability. This sensitivity is analogous to the triggering of repeating earthquakes due to tiny overall stress changes in more traditional tectonic environments (e.g., tremor modulated by tides, dynamic triggering of repeating earthquakes). Using codawave interferometry on stacks of the repeating waveforms of the families with the most events, we found that the sources move at speeds of ~1 m/day. Using a GAMMA ground based radar interferometer, we collected spatially continuous line-of-sight velocities of several glaciers at Mount Rainier in both summer and late fall. We found that the faster parts of the glaciers also move at ~1 m/day or faster, even in late fall. Movement of the sources of these repeating earthquakes at glacial speeds indicates that the asperities are dirty patches that move with the ice rather than stationary bedrock bumps. The reappearance of some event families up to several years apart suggests that certain areas at the base of certain glaciers are prodigious producers of

  6. Mid-Holocene Sector Collapse at Mount Spurr Volcano, South-Central Alaska

    USGS Publications Warehouse

    Waythomas, Christopher F.

    2007-01-01

    Radiocarbon-dated volcanic mass-flow deposits on the southeast flank of Mount Spurr in south-central Alaska provide strong evidence for the timing of large-scale destruction of the south flank of the volcano by sector collapse at 4,769^ndash;4,610 yr B.P. The sector collapse created an avalanche caldera and produced an ~1-km3-volume clay-rich debris avalanche that flowed into the glacially scoured Chakachatna River valley, where it transformed into a lahar that extended an unknown distance beyond the debris avalanche. Hydrothermal alteration, an unbuttressed south flank of the volcano, and local structure have been identified as plausible factors contributing to the instability of the edifice. The sector collapse at Mount Spurr is one of the later known large-volume (>1 km,sup>3) flank failures recognized in the Aleutian Arc and one of the few known Alaskan examples of transformation of a debris avalanche into a lahar.

  7. Gravity and magma induces spreading of Mount Etna volcano revealed by satellite radar interferometry

    NASA Technical Reports Server (NTRS)

    Lungren, P.; Casu, F.; Manzo, M.; Pepe, A.; Berardino, P.; Sansosti, E.; Lanari, R.

    2004-01-01

    Mount Etna underwent a cycle of eruptive activity over the past ten years. Here we compute ground displacement maps and deformation time series from more than 400 radar interferograms to reveal Mount Etna's average and time varying surface deformation from 1992 to 2001.

  8. Catalog of earthquake hypocenters for Augustine, Redoubt, Iliamna, and Mount Spurr volcanoes, Alaska: January 1, 1991 - December 31, 1993

    USGS Publications Warehouse

    Jolly, Arthur D.; Power, John A.; Stihler, Scott D.; Rao, Lalitha N.; Davidson, Gail; Paskievitch, John F.; Estes, Steve; Lahr, John C.

    1996-01-01

    The 1992 eruptions at Mount Spurr's Crater Peak vent provided the highlight of the catalog period. The crisis included three sub-plinian eruptions, which occurred on June 27, August 18, and September 16-17, 1992. The three eruptions punctuated a complex seismic sequence which included volcano-tectonic (VT) earthquakes, tremor, and both deep and shallow long period (LP) earthquakes. The seismic sequence began on August 18, 1991, with a small swarm of volcano-tectonic events beneath Crater Peak, and spread throughout the volcanic complex by November of the same year. Elevated levels of seismicity persisted at Mount Spurr beyond the catalog time period.

  9. Motivations for muon radiography of active volcanoes

    NASA Astrophysics Data System (ADS)

    Macedonio, G.; Martini, M.

    2010-02-01

    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).

  10. 2013 volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Dixon, James P.; Cameron, Cheryl; McGimsey, Robert G.; Neal, Christina A.; Waythomas, Chris

    2015-08-14

    The Alaska Volcano Observatory (AVO) responded to eruptions, volcanic unrest or suspected unrest, and seismic events at 18 volcanic centers in Alaska during 2013. Beginning with the 2013 AVO Summary of Events, the annual description of the AVO seismograph network and activity, once a stand-alone publication, is now part of this report. Because of this change, the annual summary now contains an expanded description of seismic activity at Alaskan volcanoes. Eruptions occurred at three volcanic centers in 2013: Pavlof Volcano in May and June, Mount Veniaminof Volcano in June through December, and Cleveland Volcano throughout the year. None of these three eruptive events resulted in 24-hour staffing at AVO facilities in Anchorage or Fairbanks.

  11. Low cost volcano deformation monitoring: optical strain measurement and application to Mount St. Helens data

    NASA Astrophysics Data System (ADS)

    Walter, Thomas R.

    2011-08-01

    This paper describes an innovative method of volcano deformation measurements, applied to camera images taken from the 2004-2008 eruption period at Mount St. Helens. Dome growth was thought to be characterized by sustained, near-linear rates of a solid dacite plug. Through spatial digital image correlation (DIC) analysis of the camera images, new evidences arise that the deformation and strain rate of the spine was more complex. DIC yielded cumulative and incremental displacements, strain and shear planes at decimetre resolution. It was found that dome extrusion rates are highly non-linear, decelerating prior to partial collapse, followed by a pronounced dome extrusion increase and direction change. Associated processes have been identified through DIC, such as shallow landslides and reworking of talus apron material. The work highlights the strengths of camera strain monitoring, and illustrates that dome growth and collapse is a very dynamic process complexly interplaying with the surrounding.

  12. Volcano collapse promoted by progressive strength reduction: New data from Mount St. Helens

    USGS Publications Warehouse

    Reid, Mark E.; Keith, Terry E.C.; Kayen, Robert; Iverson, Neal R.; Iverson, Richard M.; Brien, Dianne

    2010-01-01

    Rock shear strength plays a fundamental role in volcano flank collapse, yet pertinent data from modern collapse surfaces are rare. Using samples collected from the inferred failure surface of the massive 1980 collapse of Mount St. Helens (MSH), we determined rock shear strength via laboratory tests designed to mimic conditions in the pre-collapse edifice. We observed that the 1980 failure shear surfaces formed primarily in pervasively shattered older dome rocks; failure was not localized in sloping volcanic strata or in weak, hydrothermally altered rocks. Our test results show that rock shear strength under large confining stresses is reduced ∼20% as a result of large quasi-static shear strain, as preceded the 1980 collapse of MSH. Using quasi-3D slope-stability modeling, we demonstrate that this mechanical weakening could have provoked edifice collapse, even in the absence of transiently elevated pore-fluid pressures or earthquake ground shaking. Progressive strength reduction could promote collapses at other volcanic edifices.

  13. High resolution aeromagnetic anomaly map of Mount Etna volcano, Southern Italy

    NASA Astrophysics Data System (ADS)

    D'Ajello Caracciolo, F.; Nicolosi, I.; Carluccio, R.; Chiappini, S.; De Ritis, R.; Giuntini, A.; Materni, V.; Messina, A.; Chiappini, M.

    2014-05-01

    A high resolution aeromagnetic survey of Mount Etna Volcano was carried out by the Airborne Geophysics Science Team of Istituto Nazionale di Geofisica e Vulcanologia (INGV), aimed at producing the most detailed magnetic anomaly map existing so far for this area. Two datasets of the total intensity of the Earth's Magnetic Field were collected at different altitudes to take into account the huge topographic variations of Etna volcano, that reaches elevations above 3300 m asl. One level was flown at the altitude of 2200 m whereas a second one over the central part, at about 3500 m of altitude. Since the region is characterized by a large presence of strongly magnetized volcanic products, the survey was carried out acquiring profile lines only, in order to optimize the resources. From the residual magnetic anomaly analysis we inferred two main trending lineaments (- 35°N and 0°N) that are related to regional tectonic stress field and we interpret the main magnetic anomaly as the effect of thickness variation of magnetized volcanic products due to the complex pre-volcanic basement morphology of Etna.

  14. Climate forcing of volcano lateral collapse: evidence from Mount Etna, Sicily.

    PubMed

    Deeming, K R; McGuire, B; Harrop, P

    2010-05-28

    In this study, we present evidence for early Holocene climatic conditions providing circumstances favourable to major lateral collapse at Mount Etna, Sicily. The volcano's most notable topographic feature is the Valle del Bove, a 5 x 8 km cliff-bounded amphitheatre excavated from the eastern flank of the volcano. Its origin due to prehistoric lateral collapse is corroborated by stürtzstrom deposits adjacent to the amphitheatre's downslope outlet, but the age, nature and cause of amphitheatre excavation remain matters for debate. Cosmogenic (3)He exposure ages determined for eroded surfaces within an abandoned watershed flanking the Valle del Bove support channel abandonment ca 7.5 ka BP, as a consequence of its excavation in a catastrophic collapse event. Watershed development was largely dictated by pluvial conditions during the early Holocene, which are also implicated in slope failure. A viable trigger is magma emplacement into rift zones in the eastern flank of a water-saturated edifice, leading to the development of excess pore pressures, consequent reduction in sliding resistance, detachment and collapse. Such a mechanism is presented as one potential driver of future lateral collapse in volcanic landscapes forecast to experience increased precipitation or melting of ice cover as a consequence of anthropogenic warming.

  15. The 1928 eruption of Mount Etna volcano, Sicily, and the destruction of the town of Mascali.

    PubMed

    Duncan, A M; Dibben, C; Chester, D K; Guest, J E

    1996-03-01

    In November 1928 there was an eruption of Mount Etna, Sicily, which led to lava largely destroying the town of Mascali, situated low on the eastern flank of the volcano. Destruction of the town took just over a day but there was an orderly evacuation of its inhabitants and, with help from the military, families were able to remove furniture and fittings from their houses. Evacuees were relocated to nearby towns staying with relatives, friends or in hired apartments. Rebuilding Mascali provided an opportunity for the fascist government of the time to demonstrate efficient centralised planning. A completely new town was built on a grid-iron plan with many of the buildings reflecting the 'fascist architecture' of the time. The town was complete by 1937 and housing condztzons were very advanced in comparison with other towns in the region. The 1928 eruption is important as it was the most destructive on Etna since 1669 when the city of Catania was overwhelmed. In terms of hazard and risk assessment the 1928 eruption demonstrates that lava can reach the lower flanks of the volcano within a short period after the onset of an eruption.

  16. Geochemical mapping of magmatic gas water rock interactions in the aquifer of Mount Etna volcano

    NASA Astrophysics Data System (ADS)

    Brusca, L.; Aiuppa, A.; D'Alessandro, W.; Parello, F.; Allard, P.; Michel, A.

    2001-08-01

    Systematic analysis of major and minor elements in groundwaters from springs and wells on the slopes of Mt. Etna in 1995-1998 provides a detailed geochemical mapping of the aquifer of the volcano and of the interactions between magmatic gas, water bodies and their host rocks. Strong spatial correlations between the largest anomalies in pCO 2 (pH and alkalinity) K, Rb, Mg, Ca and Sr suggest a dominating control by magmatic gas (CO 2) and consequent basalt leaching by acidified waters of the shallow (meteoric) Etnean aquifer. Most groundwaters displaying this magmatic-type interaction discharge within active faulted zones on the S-SW and E lower flanks of the volcanic pile, but also in a newly recognised area on the northern flank, possibly tracking a main N-S volcano-tectonic structure. In the same time, the spatial distribution of T°C, TDS, Na, Li, Cl and B allows us to identify the existence of a deeper thermal brine with high salinity, high content of B, Cl and gases (CO 2, H 2S, CH 4) and low K/Na ratio, which is likely hosted in the sedimentary basement. This hot brine reaches the surface only at the periphery of the volcano near the Village of Paternò, where it gives rise to mud volcanoes called "Salinelle di Paternò". However, the contribution of similar brines to shallower groundwaters is also detected in other sectors to the W (Bronte, Maletto), SW (Adrano) and SE (Acireale), suggesting its possible widespread occurrence beneath Etna. This thermal brine is also closely associated with hydrocarbon fields all around the volcano and its rise, generally masked by the high outflow of the shallow aquifer, may be driven by the ascent of mixed sedimentary-magmatic gases through the main faults cutting the sedimentary basement.

  17. Fissure eruptions at Mount Vesuvius (Italy): Insights on the shallow propagation of dikes at volcanoes

    NASA Astrophysics Data System (ADS)

    Acocella, Valerio; Porreca, Massimiliano; Neri, Marco; Mattei, Massimo; Funiciello, Renato

    2006-08-01

    Fissure eruptions may provide important information on the shallow propagation of dikes at volcanoes. Somma-Vesuvius (Italy) consists of the active Vesuvius cone, bordered to the north by the remnants of the older Somma edifice. Historical chronicles are considered to define the development of the 37 fissure eruptions between A.D. 1631 and 1944. The 1631 fissure, which reopened the magmatic conduit, migrated upward and was the only one triggered by the subvertical propagation of a dike. The other 25 fissure eruptions migrated downward, when the conduit was open, through the lateral propagation of radial dikes. We suggest two scenarios for the development of the fissures. When the summit conduit is closed, the fissures are fed by vertically propagating dikes. When the summit conduit is open, the fissures are fed by laterally propagating dikes along the volcano slopes. Consistent behaviors are found at other composite volcanoes, suggesting a general application to our model, independent of the tectonic setting and composition of magma. At Vesuvius, the historical data set and our scenarios are used to predict the consequences of the emplacement of fissures after the opening of the conduit. The results suggest that, even though the probability of opening of vents within the inhabited south and west slopes is negligible, the possibility that these are reached by a lava flow remains significant.

  18. Leaching characteristics of ash from the May 18, 1980, eruption of Mount St. Helens volcano, Washington

    NASA Astrophysics Data System (ADS)

    Smith, D. B.; Zielinski, R. A.; Taylor, H. E.; Sawyer, M. B.

    1983-06-01

    Leaching of freshly erupted air-fall ash, unaffected by rain, from the May 18, 1980, eruption of Mount St. Helens volcano, Washington, shows that Ca2+, Na+, Mg2+, SO{4/2-}, and Cl- are the predominant chemical species released on first exposure of the ash to water. Extremely high correlation of Ca with SO4 and Na with Cl in water leachates suggests the presence of CaSO4 and NaCl salts on the ash. The amount of water soluble material on ash increases with distance from source and with the weight fraction of small (less than 63 micrometers) ash particles of high-surface area. This suggests that surface reactions such as adsorption are responsible for concentrating the soluble material. CaSO4, NaCl, and other salts are probably formed as microscopic crystals in the high-temperature core of the eruption column and are then adsorbed by silicate ash particles. The environmentally important elements Zn, Cu, Cd, F. Pb, and Ba are released by a water leach in concentrations which could pose short-term hazards to some forms of aquatic life. However, calculated concentrations are based on a water-to-ash ratio of 4:1 or less, which is probably an underestimation of the regionally operative ratio. A subsequent leach of ash by warm alkaline solution shows dramatic increases, in the amount of dissolved SiO2, U, and V, which are probably caused by increased dissolution of the glassy component of ash. Glass dissolution by alkaline ground water is a mechanism for providing these three elements to sedimentary traps where they may coaccumulate as uraniferous silica or U-V minerals. Leaching characteristics of ash from Mount St. Helens are comparable to characteristics of ash of similar composition from volcanoes in Guatemala. Ashes from each locality show similar ions predominating for a given leachate and similar fractions of a particular element in the ash removed on contact with the leach solution.

  19. Leaching characteristics of ash from the May 18, 1980, eruption of Mount St. Helens Volcano, Washington

    USGS Publications Warehouse

    Smith, David Burl; Zielinski, Robert A.; Taylor, Howard Edward

    1982-01-01

    Leaching of freshly erupted air-fall ash, unaffected by rain, from the May 18, 1.980,eruption of Mount St. Helens volcano, Washington, shows that Ca 2+, Na+, Mg+, SO4 2-, and Cl- are the predominant chemical species released on first exposure of the ash to water. Extremely high correlation of Ca with SO4 and Na with Cl in water leachates suggests the presence of CaSO4 and NaCl salts on the ash. The amount of water soluble material on ash increases with distance from source and with the weight fraction of small (less than 63 micrometers) ash particles of high-surface area. This suggests that surface reactions such as adsorption are responsible for concentrating the soluble material. CaSO4, NaCl, and other salts are probably formed as microscopic crystals in the high-temperature core of the eruption column and are then adsorbed by silicate ash particles. The environmentally important elements Zn, Cu, Cd, F, Pb, and Ba are released by a water leach in concentrations which could pose short-term hazards to some forms of aquatic life. However, calculated concentrations are based on a water-to-ash ratio of 4:1 or less, which is probably an underestimation of the regionally operative ratio. A subsequent leach of ash by warm alkaline solution shows dramatic increases in the amount of dissolved SiO2, U, and V, which are probably caused by increased dissolution of the glassy component of ash. Glass dissolution by alkaline ground water is a mechanism for providing these three elements to sedimentary traps where they may co-accumulate as uraniferous silica or U-V minerals. Leaching characteristics of ash from Mount St. Helens are comparable to characteristics of ash of similar composition from volcanoes in Guatemala. Ashes from each locality show similar ions predominating for a given leachate and similar fractions of a particular element in the ash removed on contact with the leach solution.

  20. Geological evolution of Mount Etna volcano (Italy) from earliest products until the first central volcanism (between 500 and 100 ka ago) inferred from geochronological and stratigraphic data

    NASA Astrophysics Data System (ADS)

    Branca, Stefano; Coltelli, Mauro; de Beni, Emanuela; Wijbrans, Jan

    2008-02-01

    We present an updated geological evolution of Mount Etna volcano based on new 40Ar/39Ar age determinations and stratigraphic data integrating the previous K/Ar ages. Volcanism began at about 500 ka ago through submarine eruptions on the Gela Catania Foredeep basin. About 300 ka ago fissure-type eruptions occurred on the ancient alluvial plain of the Simeto River forming a lava plateau. From about 220 ka ago the eruptive activity was localised mainly along the Ionian coast where fissure-type eruptions built a shield volcano. Between 129 and 126 ka ago volcanism shifted westward toward the central portion of the present volcano (Val Calanna Moscarello area). Furthermore, scattered effusive eruptions on the southern periphery of Etna edifice occurred until about 121 ka ago. The stabilization of the plumbing system on the Valle del Bove area is marked by the building of two small polygenic edifices, Tarderia and Rocche volcanoes. Their eruptive activity was rather coeval ending 106 and 102 ka ago, respectively. During the investigated time-span volcanism in Etna region was controlled by a main E W extensional tectonic related to the reactivation of Malta Escarpment fault system in eastern Sicily.

  1. A statistical analysis of eruptive activity on Mount Etna, Sicily

    NASA Astrophysics Data System (ADS)

    Smethurst, Lucy; James, Mike R.; Pinkerton, Harry; Tawn, Jonathan A.

    2009-10-01

    A rigorous analysis of the timing and location of flank eruptions of Mount Etna on Sicily is important for the creation of hazard maps of the densely populated area surrounding the volcano. In this paper, we analyse the temporal, volumetric and spatial data on eruptive activity on Etna. Our analyses are based on the two most recent and robust historical data catalogues of flank eruption activity on Etna, with one from 1669 to 2008 and the other from 1610 to 2008. We use standard statistical methodology and modelling techniques, though a number of features are new to the analysis of eruption data. Our temporal analysis reveals that flank eruptions on Mount Etna between 1610 and 2008 follow an inhomogeneous Poisson process, with intensity of eruptions increasing nearly linearly since the mid-1900s. Our temporal analysis reveals no evidence of cyclicity over this period. An analysis of volumetric lava flow rates shows a marked increase in activity since 1971. This increase, which coincides with the formation of the Southeast Crater (SEC), appears to be related to increased activity on and around the SEC. This has significant implications for hazard analysis on Etna.

  2. 40Ar/39Ar dating of the eruptive history of Mount Erebus, Antarctica: volcano evolution

    NASA Astrophysics Data System (ADS)

    Esser, Richard P.; Kyle, Philip R.; McIntosh, William C.

    2004-12-01

    Mt. Erebus, a 3,794-meter-high active polygenetic stratovolcano, is composed of voluminous anorthoclase-phyric tephriphonolite and phonolite lavas overlying unknown volumes of poorly exposed, less differentiated lavas. The older basanite to phonotephrite lavas crop out on Fang Ridge, an eroded remnant of a proto-Erebus volcano and at other isolated locations on the flanks of the Mt. Erebus edifice. Anorthoclase feldspars in the phonolitic lavas are large (~10 cm), abundant (~30 40%) and contain numerous melt inclusions. Although excess argon is known to exist within the melt inclusions, rigorous sample preparation was used to remove the majority of the contaminant. Twenty-five sample sites were dated by the 40Ar/39Ar method (using 20 anorthoclase, 5 plagioclase and 9 groundmass concentrates) to examine the eruptive history of the volcano. Cape Barne, the oldest site, is 1,311±16 ka and represents the first of three stages of eruptive activity on the Mt. Erebus edifice. It shows a transition from sub-aqueous to sub-aerial volcanism that may mark the initiation of proto-Erebus eruptive activity. It is inferred that a further ~300 ky of basanitic/phonotephritic volcanism built a low, broad platform shield volcano. Cessation of the shield-building phase is marked by eruptions at Fang Ridge at ~1,000 ka. The termination of proto-Erebus eruptive activity is marked by the stratigraphically highest flow at Fang Ridge (758±20 ka). Younger lavas (~550 250 ka) on a modern-Erebus edifice are characterized by phonotephrites, tephriphonolites and trachytes. Plagioclase-phyric phonotephrite from coastal and flank flows yield ages between 531±38 and 368±18 ka. The initiation of anorthoclase tephriphonolite occurred in the southwest sector of the volcano at and around Turks Head (243±10 ka). A short pulse of effusive activity marked by crustal contamination occurred ~160 ka as indicated by at least two trachytic flows (157±6 and 166±10 ka). Most

  3. Paleomagnetic constraints on the timing and duration of latest Pleistocene to early Holocene eruptions at Mount Shasta volcano, California, USA

    NASA Astrophysics Data System (ADS)

    Gardner, C. A.; Champion, D. E.; Christiansen, R. L.; Calvert, A. T.; Mosbrucker, A. R.

    2013-12-01

    Mount Shasta in northern California, USA, has among the highest late Pleistocene to early Holocene eruptive rates in the Cascades arc (Hildreth, 2007, USGS Prof Paper 1744). Paleomagnetic data from over 50 sites help constrain the timing and durations of these events. In late glacial times, lithic pyroclastic flows of unknown volume and age swept down all flanks of the volcano, followed, after a period of quiescence, by Shasta's largest known explosive event-- the pumiceous Red Banks tephra fall and pyroclastic flows at ~11 ka. The Red Banks tephra fall was closely followed by growth of the Shastina and Black Butte edifices on the west side of the volcano with the volume of the Shastina deposits alone estimated to be about 30 km3. Since cessation of activity at Shastina and Black Butte, a series of lava domes and flows built the summit Hotlum cone and inundated the N and E flanks of the volcano. Paleomagnetic secular-variation data show that the events described above have well-grouped and distinct remanence directions suggesting that individual pulses of activity occurred within short time intervals (days to decades), with periods of quiescence between them lasting longer than the eruptive activity. The total interval of time suggested by the movement of the magnetic field from pre-Red Banks through Hotlum activity is likely within 5-10 kyr. The pre-Redbanks pyroclastic flows exposed on at least three flanks of the volcano have essentially the same paleomagnetic direction of ~ D=350°, I=60° with a site mean α95of 1.8° (7/7 sites). The Red Banks eruptive products have a more easterly and shallower (~ D=2°, I=53°) remanent direction. The prominent Shastina cone on the NW flank of the volcano produced lava flows to the NW and SW of the cone and an apron of pyroclastic material to the west. Shastina pyroclastic flows and lava flows have a similar direction of ~ D=8°, I=56 (α95 from 15 sites is 1.4°) suggesting that the Shastina eruptive period lasted a

  4. Scattering and absorption mapping of tectonic and feeding structures under the pre-eruptive Mount St. Helens volcano.

    NASA Astrophysics Data System (ADS)

    De Siena, Luca; Calvet, Marie; Thomas, Christine

    2015-04-01

    Knowing how seismic waves lose their energy in space and frequency is both critical for understating volcanic structures and important to detect eventual changes in their seismic and volcanic activity. We measure both the peak-delay time and the coda quality factor on seismic envelopes recorded at Mount St. Helens volcano between 2000 and 2003, just before its 2004 explosive eruption. By the 2D mapping of these two frequency-dependent quantities we obtain S-wave scattering and absorption maps in the pre-eruptive phase of the volcano. We use a 2D K-means cluster analysis to highlight correlations in the frequency-dependent spatial patterns and interpret the results in terms of tectonic and feeding structures. The transition between the high-velocity and high-scattering Siletz terrane and the low-velocity and high-absorption Cascade arc crust is a persistent signature in the entire frequency range. At high frequencies, we observe strong correlation between high-scattering, high-absorption, and high P-wave heterogeneity (this last tomographically derived between depths of 0 and 10 km). In our interpretation, this correlation is a direct consequence of resonance effects, induced by the presence of melt and fluid inclusions as well as residuals of previous eruptions. The area of maximum heterogeneity is located south-south-west of the central crater: the region shows selective high absorption characteristics at 6 Hz only. If this supports the presence of a previously-inferred aseismic magma chamber intersecting the south-south-western flank of the volcano, the selectivity suggests a depth extension of the magma chamber lower than 1 km. The most important high-scattering and high-absorption signature at high frequencies remains a NNW-SSE suture crossing the volcanic cone and parallel to the St. Helens Seismic Zone. The trend confirms the persistent major role of the main direction of regional structural stress in the uprise of magma/fluid filled materials in the first

  5. Seismicity and infrasound associated with explosions at Mount St. Helens, 2004-2005: Chapter 6 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Moran, Seth C.; McChesney, Patrick J.; Lockhart, Andrew B.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    Six explosions occurred during 2004-5 in association with renewed eruptive activity at Mount St. Helens, Washington. Of four explosions in October 2004, none had precursory seismicity and two had explosion-related seismic tremor that marked the end of the explosion. However, seismicity levels dropped following each of the October explosions, providing the primary instrumental means for explosion detection during the initial vent-clearing phase. In contrast, explosions on January 16 and March 8, 2005, produced noticeable seismicity in the form of explosion-related tremor, infrasonic signals, and, in the case of the March 8 explosion, an increase in event size ~2 hours before the explosion. In both 2005 cases seismic tremor appeared before any infrasonic signals and was best recorded on stations located within the crater. These explosions demonstrated that reliable explosion detection at volcanoes like Mount St. Helens requires seismic stations within 1-2 km of the vent and stations with multiple acoustic sensors.

  6. Helicopter magnetic and electromagnetic surveys at Mounts Adams, Baker and Rainier, Washington: implications for debris flow hazards and volcano hydrology

    USGS Publications Warehouse

    Finn, Carol A.; Deszcz-Pan, Maria

    2011-01-01

    High‐resolution helicopter magnetic and electromagnetic (HEM) data flown over the rugged, ice‐covered Mt. Adams, Mt. Baker and Mt. Rainier volcanoes (Washington), reveal the distribution of alteration, water and ice thickness essential to evaluating volcanic landslide hazards. These data, combined with geological mapping and rock property measurements, indicate the presence of appreciable thicknesses (>500 m) of water‐saturated hydrothermally altered rock west of the modern summit of Mount Rainier in the Sunset Amphitheater region and in the central core of Mount Adams north of the summit. Alteration at Mount Baker is restricted to thinner (<300 m) zones beneath Sherman Crater and the Dorr Fumarole Fields. The EM data identified water‐saturated rocks from the surface to the detection limit (100–200 m) in discreet zones at Mt. Rainier and Mt Adams and over the entire summit region at Mt. Baker. The best estimates for ice thickness are obtained over relatively low resistivity (<800 ohm‐m) ground for the main ice cap on Mt. Adams and over most of the summit of Mt. Baker. The modeled distribution of alteration, pore fluids and partial ice volumes on the volcanoes helps identify likely sources for future alteration‐related debris flows, including the Sunset Amphitheater region at Mt. Rainier, steep cliffs at the western edge of the central altered zone at Mount Adams and eastern flanks of Mt. Baker.

  7. Operation of a digital seismic network on Mount St. Helens volcano and observations of long period seismic events that originate under the volcano

    SciTech Connect

    Fehler, M.; Chouet, B.

    1982-09-01

    A 9 station digital seismic array was operated on Mount St. Helens volcano in Washington State during 1981. One of the stations was placed inside the crater of the volcano, six were located on the flanks of the volcano within two km of the crater and two were approximately ten km from the crater. Four of the instruments recorded three components of motion and the remaining five recorded only the vertical component. A one day experiment was carried out during which the crater monitoring seismometer was complimented by the addition of two ink recording instruments. During the one day experiment six observers recorded times of rockfall, felt-earthquake occurrences, and changes in steam emissions from the dome in the crater. Using information obtained during the one day experiment seismic events recorded by the digital instruments were classified as earthquakes, rockfalls, helicopter noise and a type of event that is unique to volcanoes which is called long period. Waveforms of these long period events have a duration of up to 30 seconds and a spectrum that is peaked at approximately 2 Hz. The frequency at which the peak in the spectrum occurs is nearly the same at all stations which means that the unique waveform of long period events is due to a source effect, not a path effect. The peak frequency is fairly insensitive to the amplitude of the signal which means that the size of the source region is constant, independent of the signal amplitude. Long period events were not felt and were accompanied by no visible changes inside the crater which lead to the conclusion that they are some sort of seismic disturbance generated inside the Volcano.

  8. Rockslide-debris avalanche of May 18, 1980, Mount St. Helens Volcano, Washington

    USGS Publications Warehouse

    Glicken, Harry

    1996-01-01

    This report provides a detailed picture of the rockslide-debris avalanche of the May 18, 1980, eruption of Mount St. Helens volcano. It provides a characterization of the deposit, a reinterpretation of the details of the first minutes of the eruption of May 18, and insight into the transport mechanism of the mass movement. Details of the rockslide event, as revealed by eyewitness photographs, are correlated with features of the deposit. The photographs show three slide blocks in the rockslide movement. Slide block I was triggered by a magnitude 5.1 earthquake at 8:32 a.m. Pacific Daylight Time (P.D.T.). An exploding cryptodome burst through slide block II to produce the 'blast surge.' Slide block III consisted of many discrete failures that were carried out in continuing pyroclastic currents generated from the exploding cryptodome. The cryptodome continued to depressurize after slide block III, producing a blast deposit that rests on top of the debris-avalanche deposit. The hummocky 2.5 cubic kilometer debris-avalanche deposit consists of block facies (pieces of the pre-eruption Mount St. Helens transported relatively intact) and matrix facies (a mixture of rocks from the old mountain and cryptodome dacite). Block facies is divided into five lithologic units. Matrix facies was derived from the explosively generated current of slide block III as well as from disaggregation and mixing of debris-avalanche blocks. The mean density of the old cone was measured to be abut 20 percent greater than the mean density of the avalanche deposit. Density in the deposit does not decrease with distance which suggests that debris-avalanche blocks were dilated at the mountain, rather than during transport. Various grain-size parameters that show that clast size converges about a mean with distance suggest mixing during transport. The debris-avalanche flow can be considered a grain flow, where particles -- either debris-avalanche blocks or the clasts within the blocks -- collided and

  9. Evidence for ground motion polarization on fault zones of Mount Etna volcano

    NASA Astrophysics Data System (ADS)

    Rigano, Rosaria; Cara, Fabrizio; Lombardo, Giuseppe; Rovelli, Antonio

    2008-10-01

    During local and regional earthquakes, an evident amplification of horizontal ground motion is observed at two seismological stations near the Tremestieri fault, on the southeastern flank of Mount Etna volcano. Rotated component spectral ratios show a narrow spectral peak around 4 Hz along a N40°E direction. A conventional polarization analysis using the eigenvectors of the covariance matrix confirms the very stable directional effect enhancing the approximately NE-SW elongation of the horizontal ground motion in the fault zone. The effect is evident during the entire seismogram and independent of source back azimuth as well as distance and depth of earthquakes. The same polarization is observed in ambient noise as well. This consistency allowed us to use microtremors for checking ground motion polarization along and across the Tremestieri fault zone with a high spatial resolution. The result is a stable polarization of horizontal motion in the entire area that can be observed in a broad frequency band. To check whether this ground motion property is recurrent and to understand a possible relationship with fault strike, faulting style, or orientation of fractures, ambient noise was recorded on other mapped faults of the Mount Etna area, the Moscarello, Acicatena, and Pernicana faults. The latter, in particular, is characterized by different strike and faulting style. A systematic tendency of ambient noise to be polarized is found in all of the faults. A picture emerges where normal faults of the eastern flank show an E-W to NE-SW polarization that changes on the Pernicana fault, which develops approximately E-W and is characterized by a prevailing NW-SE to N-S polarization. Directions of polarization were never parallel to the fault strike. Moreover, polarization persists too far away from the fault trace, excluding an effect limited to a narrow low-velocity zone hosted between harder wall rocks. Both these observations rule out an interpretation in terms of fault

  10. Distinguishing between stress-induced and structural anisotropy at Mount Ruapehu volcano, New Zealand

    USGS Publications Warehouse

    Johnson, J.H.; Savage, M.K.; Townend, J.

    2011-01-01

    We have created a benchmark of spatial variations in shear wave anisotropy around Mount Ruapehu, New Zealand, against which to measure future temporal changes. Anisotropy in the crust is often assumed to be caused by stress-aligned microcracks, and the polarization of the fast quasi-shear wave (??) is thus interpreted to indicate the direction of maximum horizontal stress, but can also be due to aligned minerals or macroscopic fractures. Changes in seismic anisotropy have been observed following a major eruption in 1995/96 and were attributed to changes in stress from the depressurization of the magmatic system. Three-component broadband seismometers have been deployed to complement the permanent stations that surround Ruapehu, creating a combined network of 34 three-component seismometers. This denser observational network improves the resolution with which spatial variations in seismic anisotropy can be examined. Using an automated shear wave splitting analysis, we examine local earthquakes in 2008. We observe a strong azimuthal dependence of ?? and so introduce a spatial averaging technique and two-dimensional tomography of recorded delay times. The anisotropy can be divided into regions in which ?? agrees with stress estimations from focal mechanism inversions, suggesting stress-induced anisotropy, and those in which ?? is aligned with structural features such as faults, suggesting structural anisotropy. The pattern of anisotropy that is inferred to be stress related cannot be modeled adequately using Coulomb modeling with a dike-like inflation source. We suggest that the stress-induced anisotropy is affected by loading of the volcano and a lithospheric discontinuity. Copyright 2011 by the American Geophysical Union.

  11. Mount St. Helens erupts again: activity from September 2004 through March 2005

    USGS Publications Warehouse

    Major, Jon J.; Scott, William E.; Driedger, Carolyn; Dzurisin, Dan

    2005-01-01

    Eruptive activity at Mount St. Helens captured the world’s attention in 1980 when the largest historical landslide on Earth and a powerful explosion reshaped the volcano, created its distinctive crater, and dramatically modified the surrounding landscape. Over the next 6 years, episodic extrusions of lava built a large dome in the crater. From 1987 to 2004, Mount St. Helens returned to a period of relative quiet, interrupted by occasional, short-lived seismic swarms that lasted minutes to days, by months-to-yearslong increases in background seismicity that probably reflected replenishment of magma deep underground, and by minor steam explosions as late as 1991. During this period a new glacier grew in the crater and wrapped around and partly buried the lava dome. Although the volcano was relatively quiet, scientists with the U.S. Geological Survey and University of Washington’s Pacific Northwest Seismograph Network continued to closely monitor it for signs of renewed activity.

  12. Volcanoes

    ERIC Educational Resources Information Center

    Kunar, L. N. S.

    1975-01-01

    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)

  13. Volcanoes

    SciTech Connect

    Decker, R.W.; Decker, B.

    1989-01-01

    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.

  14. The discovery of late Quaternary basalt on Mount Bambouto: Implications for recent widespread volcanic activity in the southern Cameroon Line

    NASA Astrophysics Data System (ADS)

    Kagou Dongmo, Armand; Nkouathio, David; Pouclet, André; Bardintzeff, Jacques-Marie; Wandji, Pierre; Nono, Alexandre; Guillou, Hervé

    2010-04-01

    At the north-eastern flank of Mount Bambouto, a lateral cone, the Totap volcano, is dated at 0.480 ± 0.014 Ma, which corresponds to the most recent activity of this area. The lava is a basanite similar to the older basanites of Mount Bambouto. Two new datations of the lavas of the substratum are 11.75 ± 0.25 Ma, and 21.12 ± 0.45 Ma. A synthetic revision of the volcanic story of Mount Bambouto is proposed as follows. The first stage, ca. 21 Ma, corresponds to the building of the initial basaltic shield volcano. The second stage, from 18.5 to 15.3 Ma, is marked by the collapse of the caldera linked to the pouring out of ignimbritic rhyolites and trachytes. The third stage, from 15 to 4.5 Ma, renews with basaltic effusive activity, together with post-caldera extrusions of trachytes and phonolites. The 0.5 Ma Totap activity could be a fourth stage. In the recent Quaternary, a number of basaltic activities, similar to that of the Totap volcano, are encountered elsewhere in the Cameroon Line, from Mount Oku to Mount Cameroon. The very long-live activity at Mount Bambouto and the volcanic time-space distribution in the southern Cameroon Line are linked to the working of a hotline.

  15. Degassing Processes at Persistently Active Explosive Volcanoes

    NASA Astrophysics Data System (ADS)

    Smekens, Jean-Francois

    Among volcanic gases, sulfur dioxide (SO2) is by far the most commonly measured. More than a monitoring proxy for volcanic degassing, SO 2 has the potential to alter climate patterns. Persistently active explosive volcanoes are characterized by short explosive bursts, which often occur at periodic intervals numerous times per day, spanning years to decades. SO 2 emissions at those volcanoes are poorly constrained, in large part because the current satellite monitoring techniques are unable to detect or quantify plumes of low concentration in the troposphere. Eruption plumes also often show high concentrations of ash and/or aerosols, which further inhibit the detection methods. In this work I focus on quantifying volcanic gas emissions at persistently active explosive volcanoes and their variations over short timescales (minutes to hours), in order to document their contribution to natural SO2 flux as well as investigate the physical processes that control their behavior. In order to make these measurements, I first develop and assemble a UV ground-based instrument, and validate it against an independently measured source of SO2 at a coal-burning power plant in Arizona. I establish a measurement protocol and demonstrate that the instrument measures SO 2 fluxes with < 20 % error. Using the same protocol, I establish a record of the degassing patterns at Semeru volcano (Indonesia), a volcano that has been producing cycles of repeated explosions with periods of minutes to hours for the past several decades. Semeru produces an average of 21-71 tons of SO2 per day, amounting to a yearly output of 8-26 Mt. Using the Semeru data, along with a 1-D transient numerical model of magma ascent, I test the validity of a model in which a viscous plug at the top of the conduit produces cycles of eruption and gas release. I find that it can be a valid hypothesis to explain the observed patterns of degassing at Semeru. Periodic behavior in such a system occurs for a very narrow range

  16. Temporal and spatial variation of local stress fields before and after the 1992 eruptions of Crater Peak vent, Mount Spurr volcano, Alaska

    USGS Publications Warehouse

    Roman, D.C.; Moran, S.C.; Power, J.A.; Cashman, K.V.

    2004-01-01

    We searched for changes in local stress-field orientation at Mount Spurr volcano, Alaska, between August 1991 and December 2001. This study focuses on the stress-field orientation beneath Crater Peak vent, the site of three eruptions in 1992, and beneath the summit of Mount Spurr. Local stress tensors were calculated by inverting subsets of 140 fault-plane solutions for earthquakes beneath Crater Peak and 96 fault-plane solutions for earthquakes beneath Mount Spurr. We also calculated an upper-crustal regional stress tensor by inverting fault-plane solutions for 66 intraplate earthquakes located near Mount Spurr during 1991-2001. Prior to the 1992 eruptions, and for 11 months beginning with a posteruption seismic swarm, the axis of maximum compressive stress beneath Crater Peak was subhorizontal and oriented N67-76??E, approximately perpendicular to the regional axis of maximum compressive stress (N43??W). The strong temporal correlation between this horizontal stress-field rotation (change in position of the ??1/ ??3 axes relative to regional stress) and magmatic activity indicates that the rotation was related to magmatic activity, and we suggest that the Crater Peak stress-field rotation resulted from pressurization of a network of dikes. During the entire study period, the stress field beneath the summit of Mount Spurr also differed from the regional stress tensor and was characterized by a vertical axis of maximum compressive stress. We suggest that slip beneath Mount Spurr's summit occurs primarily on a major normal fault in response to a combination of gravitational loading, hydrothermal circulation, and magmatic processes beneath Crater Peak. Online material: Regional and local fault-plane solutions.

  17. Pressurization and depressurization phases inside the plumbing system of Mount Etna volcano: Evidence from a multiparametric approach

    NASA Astrophysics Data System (ADS)

    Cannata, Andrea; Spedalieri, Giancarlo; Behncke, Boris; Cannavò, Flavio; Di Grazia, Giuseppe; Gambino, Salvatore; Gresta, Stefano; Gurrieri, Sergio; Liuzzo, Marco; Palano, Mimmo

    2015-09-01

    During 2013 Mount Etna volcano experienced intense eruptive activity at the summit craters, foremost at the New Southeast Crater and to a minor degree at the Voragine and Bocca Nuova (BN), which took place in two cycles, February-April and September-December. In this work, we mainly focus on the period between these cycles, applying a multiparametric approach. The period from the end of April to 5 September showed a gradual increase in the amplitude of long-period (LP) events and volcanic tremor, a slight inflation testified by both tilt and GPS data, and a CO2 flux increase. Such variations were interpreted as due to a gradual pressurization of the plumbing system, from the shallowest part, where LP and volcanic tremor are located, down to about 3-9 km below sea level, pressure source depths obtained by both geodetic and CO2 data. On 5 September, at the same time as a large explosion at BN, we observed an instantaneous variation of the aforementioned signals (decrease in amplitude of LP events and volcanic tremor, slight deflation, and CO2 flux decrease) and the activation of a new infrasonic source located at BN. In the light of it, the BN explosion probably caused the instantaneous end of the pressurization, and the opening of a new vent at BN, that has become a new steady source of infrasonic events. This apparently slight change in the plumbing system also led to the gradual resumption of activity at the New Southeast Crater, culminating with the second lava fountain cycle of 2013.

  18. The 1992 eruptions of Crater Peak vent, Mount Spurr Volcano, Alaska

    USGS Publications Warehouse

    Keith, Terry E.C.

    1995-01-01

    Sulfur dioxide scrubbing by liquid water masked SO2 emissions from shallow magma during the 1992 eruptions of Crater Peak and effectively prevented observation of SO2 emissions from shallow magma both before and after explosive eruptions and seismic crises. Airborne ultraviolet correlation spectrometer (COSPEC) measurements from July 22, 1991, to September 24, 1992, indicate only background to minor ( H2S(aq) + 3H+(aq) + 3HSO4-(aq). Sulfur dioxide hydrolysis also explains the increase in the sulfate content of Crater Peak lake water prior to the first eruption, the strong H2S odor during periods of background to low SO2 emission, the TOMS evidence for significant H2S emissions during the explosive eruptions, and the observed decline of SO2 during periods of volcanic tremor. Abundant, local sources of melt water and a high permeability for the Mount Spurr volcanic edifice are probably the chief factors responsible for masking SO2 emissions by scrubbing, and possibly for quenching shallow intrusions that were ascending. Large SO2 emissions unencumbered by scrubbing were only possible during the three explosive eruptions when magma penetrated through liquid water zones under Crater Peak and reached the surface. Nonexplosive SO2 emissions of as much as 750 t/d were possible, however, for a brief period when dry pathways to the surface existed from September 25 until about October 10, 1992. Airborne infrared spectrometer (MIRAN) measurements of CO2 emissions indicate that in addition to the degassing of magma through dry pathways, degassing through boiling water with the loss of SO2 by scrubbing was also important during that time. The CO2 emission data indicate that magma degassing was taking place, and CO2/SO2 values calculated from MIRAN and COSPEC data are in the range 10 to 100, which supports the hypothesis of SO2 loss by scrubbing. Because of its strong preference for the vapor phase during boiling, CO2 emissions from degassing magma are less likely to be masked

  19. Dante's Volcano

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This video contains two segments: one a 0:01:50 spot and the other a 0:08:21 feature. Dante 2, an eight-legged walking machine, is shown during field trials as it explores the inner depths of an active volcano at Mount Spurr, Alaska. A NASA sponsored team at Carnegie Mellon University built Dante to withstand earth's harshest conditions, to deliver a science payload to the interior of a volcano, and to report on its journey to the floor of a volcano. Remotely controlled from 80-miles away, the robot explored the inner depths of the volcano and information from onboard video cameras and sensors was relayed via satellite to scientists in Anchorage. There, using a computer generated image, controllers tracked the robot's movement. Ultimately the robot team hopes to apply the technology to future planetary missions.

  20. Long-term changes in quiescent degassing at Mount Baker Volcano, Washington, USA; Evidence for a stalled intrusion in 1975 and connection to a deep magma source

    USGS Publications Warehouse

    Werner, C.; Evans, William C.; Poland, M.; Tucker, D.S.; Doukas, M.P.

    2009-01-01

    Long-term changes have occurred in the chemistry, isotopic ratios, and emission rates of gas at Mount Baker volcano following a major thermal perturbation in 1975. In mid-1975 a large pulse in sulfur and carbon dioxide output was observed both in emission rates and in fumarole samples. Emission rates of CO2 and H2S were ??? 950 and 112??t/d, respectively, in 1975; these decreased to ??? 150 and < 1??t/d by 2007. During the peak of the activity the C/S ratio was the lowest ever observed in the Cascade Range and similar to magmatic signatures observed at other basaltic-andesite volcanoes worldwide. Increases in the C/S ratio and decreases in the CO2/CH4 ratio since 1975 suggest a long steady trend back toward a more hydrothermal gas signature. The helium isotope ratio is very high (> 7??Rc/RA), but has declined slightly since the mid-1970s, and ??13C-CO2 has decreased by ??? 1??? over time. Both trends are expected from a gradually crystallizing magma. While other scenarios are investigated, we conclude that magma intruded the mid- to shallow-crust beneath Mount Baker during the thermal awakening of 1975. Since that time, evidence for fresh magma has waned, but the continued emission of CO2 and the presence of a long-term hydrothermal system leads us to suspect some continuing connection between the surface and deep convecting magma.

  1. Living on Active Volcanoes - The Island of Hawai'i

    USGS Publications Warehouse

    Heliker, Christina; Stauffer, Peter H.; Hendley, James W.

    1997-01-01

    People on the Island of Hawai'i face many hazards that come with living on or near active volcanoes. These include lava flows, explosive eruptions, volcanic smog, damaging earthquakes, and tsunamis (giant seawaves). As the population of the island grows, the task of reducing the risk from volcano hazards becomes increasingly difficult. To help protect lives and property, U.S. Geological Survey (USGS) scientists at the Hawaiian Volcano Observatory closely monitor and study Hawai'i's volcanoes and issue timely warnings of hazardous activity.

  2. Mount St. Helens' volcanic ash: hemolytic activity.

    PubMed

    Vallyathan, V; Mentnech, M S; Stettler, L E; Dollberg, D D; Green, F H

    1983-04-01

    Volcanic ash samples from four Mount St. Helens' volcanic eruptions were subjected to mineralogical, analytical, and hemolytic studies in order to evaluate their potential for cytotoxicity and fibrogenicity. Plagioclase minerals constituted the major component of the ash with free crystalline silica concentrations ranging from 1.5 to 7.2%. The in vitro hemolytic activity of the volcanic ash was compared to similar concentrations of cytotoxic and inert minerals. The ash was markedly hemolytic, exhibiting an activity similar to chrysotile asbestos, a known fibrogenic agent. The hemolysis of the different ash samples varied with particle size but not with crystalline silica concentration. The results of these studies taken in conjunction with the results of our animal studies indicate a fibrogenic potential of volcanic ash in heavily exposed humans.

  3. 1995 volcanic activity in Alaska and Kamchatka: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Neal, Christina A.

    1996-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptive activity or suspected volcanic activity (SVA) at 6 volcanic centers in 1995: Mount Martin (Katmai Group), Mount Veniaminof, Shishaldin, Makushin, Kliuchef/Korovin, and Kanaga. In addition to responding to eruptive activity at Alaska volcanoes, AVO also disseminated information for the Kamchatkan Volcanic Eruption Response Team (KVERT) on the 1995 eruptions of 2 Russian volcanoes: Bezymianny and Karymsky. This report summarizes volcanic activity in Alaska during 1995 and the AVO response, as well as information on the 2 Kamchatkan eruptions. Only those reports or inquiries that resulted in a "significant" investment of staff time and energy (here defined as several hours or more for reaction, tracking, and follow-up) are included. AVO typically receives dozens of phone calls throughout the year reporting steaming, unusual cloud sightings, or eruption rumors. Most of these are resolved quickly and are not tabulated here as part of the 1995 response record.

  4. Mapping a Volcano Hazard Area of Mount Sinabung Using Drone: Preliminary Results

    NASA Astrophysics Data System (ADS)

    Tarigan, A. P. M.; Suwardhi, D.; Fajri, M. N.; Fahmi, F.

    2017-03-01

    Mount Sinabung is still active since its first eruption in 2010 and has been declared as national disaster. The persistent eruptions afterward have been lively and affected severely the surrounding villages located within the 5 km from its crater. The purpose of this study is to explore drone technology and its applicability in mapping a volcanic hazard area. The first essential step in this study is to have a well-defined mission flight in order to acquire air photos that can be processed in the subsequent procedures. The following steps including geometry correction and photos stitching were conducted automatically using proper software. It is found that the resulting photo mosaic and 3D map can be obtained in effective and efficient manner and several important interpretations can be made from them.

  5. Remote camera observations of lava dome growth at Mount St. Helens, Washington, October 2004 to February 2006: Chapter 11 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Poland, Michael P.; Dzurisin, Daniel; LaHusen, Richard G.; Major, John J.; Lapcewich, Dennis; Endo, Elliot T.; Gooding, Daniel J.; Schilling, Steve P.; Janda, Christine G.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    Images from a Web-based camera (Webcam) located 8 km north of Mount St. Helens and a network of remote, telemetered digital cameras were used to observe eruptive activity at the volcano between October 2004 and February 2006. The cameras offered the advantages of low cost, low power, flexibility in deployment, and high spatial and temporal resolution. Images obtained from the cameras provided important insights into several aspects of dome extrusion, including rockfalls, lava extrusion rates, and explosive activity. Images from the remote, telemetered digital cameras were assembled into time-lapse animations of dome extrusion that supported monitoring, research, and outreach efforts. The wide-ranging utility of remote camera imagery should motivate additional work, especially to develop the three-dimensional quantitative capabilities of terrestrial camera networks.

  6. GlobVolcano: Earth Observation Services for global monitoring of active volcanoes

    NASA Astrophysics Data System (ADS)

    Tampellini, L.; Ratti, R.; Borgström, S.; Seifert, F. M.; Solaro, G.

    2009-04-01

    The GlobVolcano project is part of the Data User Element (DUE) programme of the European Space Agency (ESA). The objective of the project is to demonstrate EO-based (Earth Observation) services able to support the Volcanological Observatories and other mandate users (Civil Protection, scientific communities of volcanoes) in their monitoring activities. The information service is assessed in close cooperation with the user organizations for different types of active volcano, from various geographical areas in various climatic zones. Users are directly and actively involved in the validation of the Earth Observation products, by comparing them with ground data available at each site. The following EO-based information services have been defined, harmonising the user requirements provided by a worldwide selection of user organizations. - Deformation Mapping - Surface Thermal Anomalies - Volcanic Gas Emission (SO2) - Volcanic Ash Tracking During the first phase of the project (completed in June 2008) a pre-operational information system has been designed, implemented and validated, involving a limited number of test areas and respective user organizations (i.e. Piton de la Fournaise in La Reunion Island, Karthala in Comore Islands, Stromboli, Volcano and Etna in Italy, Soufrière Hills in Montserrat Island, Colima in Mexico, Merapi in Indonesia). The second phase of the project (currently on-going) concerns the service provision on pre-operational basis. Fifteen volcanic sites located in four continents are regularly monitored and as many user organizations are involved and cooperating with the project team. Based on user requirements, the GlobVolcano Information System has been developed following system engineering rules and criteria, besides most recent interoperability standards for geospatial data. The GlobVolcano Information System includes two main elements: 1. The GlobVolcano Data Processing System, which consists of seven of EO data processing subsystems

  7. July 1973 ground survey of active Central American volcanoes

    NASA Technical Reports Server (NTRS)

    Stoiber, R. E. (Principal Investigator); Rose, W. I., Jr.

    1973-01-01

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

  8. Remote sensing of Italian volcanos

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

    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.

  9. Seismic scattering and absorption mapping of debris flows, feeding paths, and tectonic units at Mount St. Helens volcano

    NASA Astrophysics Data System (ADS)

    De Siena, L.; Calvet, M.; Watson, K. J.; Jonkers, A. R. T.; Thomas, C.

    2016-05-01

    Frequency-dependent peak-delay times and coda quality factors have been used jointly to separate seismic absorption from scattering quantitatively in Earth media at regional and continental scale; to this end, we measure and map these two quantities at Mount St. Helens volcano. The results show that we can locate and characterize volcanic and geological structures using their unique contribution to seismic attenuation. At 3 Hz a single high-scattering and high-absorption anomaly outlines the debris flows that followed the 1980 explosive eruption, as deduced by comparison with remote sensing imagery. The flows overlay a NNW-SSE interface, separating rocks of significant varying properties down to 2-4 km, and coinciding with the St. Helens Seismic Zone. High-scattering and high-absorption anomalies corresponding to known locations of magma emplacement follow this signature under the volcano, showing the important interconnections between its feeding systems and the regional tectonic boundaries. With frequency increasing from 6 to 18 Hz the NNW-SSE tectonic/feeding trends rotate around an axis centered on the volcano in the direction of the regional-scale magmatic arc (SW-NE). While the aseismic high-scattering region WSW of the volcano shows no evidence of high absorption, the regions of highest-scattering and absorption are consistently located at all frequencies under either the eastern or the south-eastern flank of the volcanic edifice. From the comparison with the available geological and geophysical information we infer that these anomalies mark both the location and the trend of the main feeding systems at depths greater than 4 km.

  10. Seismic scattering and absorption mapping of debris flows, feeding paths, and tectonic units at Mount St. Helens volcano

    NASA Astrophysics Data System (ADS)

    De Siena, Luca; Calvet, Marie; Watson, Keira J.; Jonkers, Art R. D.; Thomas, Christine

    2016-04-01

    Frequency-dependent peak-delay times and coda quality factors have been used jointly to separate seismic absorption from scattering quantitatively in Earth media at regional and lithospheric scale; to this end, we measure and map these two quantities at Mount St. Helens volcano. The results show that we can locate and characterise volcanic and geological structures using their unique contribution to seismic attenuation. At 3 Hz a single high-scattering and high-absorption anomaly outlines the debris flows that followed the 1980 explosive eruption, as deduced by comparison with remote sensing imagery. The flows overlay a NNW-SSE interface, separating rocks of significant varying properties down to 2-4 km, and coinciding with the Saint Helens Seismic Zone. High-scattering and high-absorption anomalies corresponding to known locations of magma emplacement follow this signature under the volcano, showing the important interconnections between its feeding systems and the regional tectonic boundaries. With frequency increasing from 6 to 18 Hz the NNW-SSE tectonic/feeding trends rotate around an axis centered on the volcano in the direction of the regional-scale magmatic arc (SW-NE). While the aseismic high-scattering region WSW of the volcano shows no evidence of high absorption, the regions of highest-scattering and absorption are consistently located at all frequencies under either the eastern or the south-eastern flank of the volcanic edifice. From the comparison with the available geological and geophysical information we infer that these anomalies mark both the location and the trend of the main feeding systems at depths greater than 4 km.

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

    USGS Publications Warehouse

    Waitt, R.B.

    1989-01-01

    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

  12. Global data collection and the surveillance of active volcanoes

    USGS Publications Warehouse

    Ward, P.L.

    1990-01-01

    Data relay systems on existing earth-orbiting satellites provide an inexpensive way to collect environmental data from numerous remote sites around the world. This technology could be used effectively for fundamental monitoring of most of the world's active volcanoes. Such global monitoring would focus attention on the most dangerous volcanoes that are likely to significantly impact the geosphere and the biosphere. ?? 1990.

  13. Response of hamster trachea in organ culture to Mount St. Helens volcano ash.

    PubMed

    Schiff, L J; Byrne, M M; Elliott, S F; Moore, S J; Ketels, K V; Graham, J A

    1981-01-01

    The effects of Mount St. Helens volcanic ash on rings of hamster tracheal epithelium in organ culture were studied. Volcanic ash samples with mass median aerodynamic diameters (MMAD) of 7.7 micrometers and 1.6 micrometers caused markedly different alterations in the tracheal mucosa. Examination by SEM of the ventral epithelial surface of tissue from untreated control explants after 2 weeks in culture showed equal numbers of ciliated and microvillous cells. Examination by SEM of tracheas exposed to the smaller size particles revealed that ash concentrations as low as 1 microgram/ml increased mucous secretion after one 2-hr exposure. After four or nine 2-hr exposures, cells contained cilia that were short and blunt. Ciliary activity after these exposures showed a significant depression in beating frequency. Tracheal ring cultures exposed to the larger volcanic ash particles exhibited moderate cytomorphological changes after one 2-hr exposure at concentrations of 1, 10 and 100 micrograms/ml. As the number of exposures increased, most of the columnar cell layer was lost, resulting in exposure of the basal cells. After nine exposures at the two highest concentrations of ash (10 and 100 micrograms/ml), only a few ciliated cells were remaining. Statistically significant reductions in ciliary activity paralleled the epithelial damage. The degree of epithelial damage and changes in the cilia beating frequency were related to the dose and the number of exposures to the volcanic ash.

  14. Volcanoes

    MedlinePlus

    ... hot gases and debris called pyroclastic flows. Some dangers from volcanoes can be predicted ahead of time ... for All Disasters Illnesses, injuries, carbon monoxide poisoning, animals & insects, food, water, cleanup, mold, environmental concerns, and ...

  15. Petrology and geochemistry of high cascade volcanics in southern Washington: Mount St. Helens volcano and the Indian Heaven basalt field

    SciTech Connect

    Smith, D.R.

    1984-01-01

    Mount St. Helens volcano (Washington, USA) has been characterized by four eruptive periods during the last 2200 years. Eruptive products include a wide spectrum of rock types including basaltic to andesitic lavas, andesitic to dacitic pyroclastic flows and tephra, and dacite domes. The major and trace element compositions of some andesites and dacites are broadly consistent with their derivation from a basaltic andesite parental magma by fractional cyrstallization processes involving the observed phenocryst assemblages. However, the strontium and oxygen isotopic compositions of representative samples of the Mount St. Helens suite indicate that closed system processes cannot explain the isotopic variations. The isotopic rations are positively correlated with one another and the bulk composition (SiO/sub 2/, Mg number, etc.). The vents of the nearby Indian Heaven Quaternary volcanic field erupted several basalt types which can be defined on the basis of major and trace element composition - calcalkaline (low and high TiO/sub 2/ varieties), transitional, and tholeiitic. Several of these basalt types occur at Mount St. Helens as well, but Indian Heaven lavas are generally more primitive as indicated by higher Mg/(Mg + Fe) ratios. The distribution of volcanic rock types in relation to local structures in the Cascade Range of southern Washington and northern Oregon suggests that crustal structure may influence the degree of evolution of specific volcanic fields. Cascade arc suggests that volcanic arc magma evolution does not necessarily produce a continuous sequence from tholeiitic to calcalkaline rocks in time or space.

  16. Near-real-time information products for Mount St. Helens -- tracking the ongoing eruption: Chapter 3 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Qamar, Anthony I.; Malone, Stephen; Moran, Seth C.; Steele, William P.; Thelen, Weston A.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    The rapid onset of energetic seismicity on September 23, 2004, at Mount St. Helens caused seismologists at the Pacific Northwest Seismic Network and the Cascades Volcano Observatory to quickly improve and develop techniques that summarized and displayed seismic parameters for use by scientists and the general public. Such techniques included webicorders (Web-based helicorder-like displays), graphs showing RSAM (real-time seismic amplitude measurements), RMS (root-mean-square) plots, spectrograms, location maps, automated seismic-event detectors, focal mechanism solutions, automated approximations of earthquake magnitudes, RSAM-based alarms, and time-depth plots for seismic events. Many of these visual-information products were made available publicly as Web pages generated and updated routinely. The graphs and maps included short written text that explained the concepts behind them, which increased their value to the nonseismologic community that was tracking the eruption. Laypeople could read online summaries of the scientific interpretations and, if they chose, review some of the basic data, thereby providing a better understanding of the data used by scientists to make interpretations about ongoing eruptive activity, as well as a better understanding of how scientists worked to monitor the volcano.

  17. The Influence of Crystal Mush on Magmatism Under Arc Volcanoes Recorded in Zircon from the Lassen Volcanic Center, California and Mount Hood, Oregon

    NASA Astrophysics Data System (ADS)

    Klemetti, E. W.; Clynne, M. A.; Kent, A. J.; Bertolett, E. M.; Hernandez, L. D.; Coble, M. A.

    2015-12-01

    Many arc volcanoes are constructed by repeated tapping of complex subvolcanic magmatic plumbing containing new and inherited crystals and liquids that interact in the hours to millennia prior to an eruption. This process is often modulated by long-lived (10-100 k.y.) shallow (<5 km) silicic crystal mush. Constraining the development and growth of mush zones is therefore essential in predicting a volcano's future behavior. The Lassen Volcanic Center (LVC) in California and Mount Hood (MH) in Oregon are two of the most recently active Cascade volcanoes, with last major eruptions in 1915 and ~1780-81 respectively. We performed U-Th/U-Pb dating of LVC and MH zircon from lavas and tephras erupted between 0.1-825 ka. In the LVC, the Rockland Tephra (611 ka; Ar/Ar) contains zircon from 800-520 ka, spanning the age of the Rockland caldera complex (825-611 ka eruption ages). During the Lassen Domefield (315-0.1 ka eruption ages), zircon ages vary from secular equilibrium to 15 ka, overlapping with the Bumpass Sequence (315-190 ka eruption ages) and an eruptive hiatus (190-90 ka eruption ages). Nine of 116 Lassen Domefield zircon are in secular equilibrium (>350 ka). These data support a model of long-lived zircon-saturated silicic mushes existing under the LVC during the Rockland caldera complex stage and since the end of the Brokeoff Volcano stage (590-385 ka eruption ages). Preliminary zircon data from the Old Maid stage (~0.2 ka eruption age) at MH indicate two broad age groups. Younger zircon (<10 ka) suggest reactivation and/or expansion of mush following Polallie phase (20-12 ka eruption ages), Timberline (~1.5 ka eruption age), and Old Maid eruptions. Older zircon (>100 ka) are generally consistent with U-Th ages from plagioclase (~120 ka U-Th), indicating a long-lived zircon-saturated crystal mush tapped by Timberline and Old Maid lavas. At both of these volcanoes, silicic crystal mushes interact with intruding mafic magma, producing monotonous mixed andesite

  18. Seismic and acoustic observations at Mount Erebus Volcano, Ross Island, Antarctica, 1994 1998

    NASA Astrophysics Data System (ADS)

    Rowe, C. A.; Aster, R. C.; Kyle, P. R.; Dibble, R. R.; Schlue, J. W.

    2000-08-01

    Volcanic activity at Mount Erebus is dominated by eruptive activity within a phonolitic summit lava lake. Common eruption styles range from passive degassing to Strombolian explosions, which typically occur several times daily, and occasionally in swarms of up to 900 per day. Shallow explosions, although generally the result of steady exsolution of volatiles from depth, can be triggered by surficial input of H 2O through mass wasting of rock, snow and ice from the crater walls. Broadband observations of Strombolian explosions document very-long-period (VLP) signals with strong spectral peaks near 20, 12 and 7 s, which are polarized in the vertical/radial plane. These signals precede lava lake surface explosions by ˜1.5 s, are highly repeatable, and persist for up to 200 s. First motions indicate a deflationary source, with any precursory inflation being below the ˜30 s passband of our instruments. Particle motions suggest a VLP source residing up to 800 m below the lava lake surface; however, this depth could be exaggerated by near-field radial tilt. Seismic and acoustic signals associated with lava lake explosions commonly show evidence for multiple bubble bursts in corresponding complexity features resulting from varying time delays and relative sizes of superimposed bursts. A systematic decrease in seismic/acoustic ratio for smaller surface explosions suggests that either the seismic energy from the smallest, shallowest bubble bursts experiences much greater seismic attenuation than energy arising from larger events which may involve a deeper, less attenuative portion of the magma column, and/or that the shallowest layer is seismically isolated from deeper parts of a stratified magma column, which are not excited by the smallest explosions due to sharp impedance contrasts across distinct layers. Tremor at Erebus is uncommon, with only a few isolated instances identified in five years of monitoring. Some tremor events are nearly monochromatic, and some exhibit

  19. Radar interferometry observations of surface displacements during pre- and coeruptive periods at Mount St. Helens, Washington, 1992-2005: Chapter 18 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Poland, Michael; Lu, Zhong; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    We analyzed hundreds of interferograms of Mount St. Helens produced from radar images acquired by the ERS-1/2, ENVISAT, and RADARSAT satellites during the 1992-2004 preeruptive and 2004-2005 coeruptive periods for signs of deformation associated with magmatic activity at depth. Individual interferograms were often contaminated by atmospheric delay anomalies; therefore, we employed stacking to amplify any deformation patterns that might exist while minimizing random noise. Preeruptive interferograms show no signs of volcanowide deformation between 1992 and the onset of eruptive activity in 2004. Several patches of subsidence in the 1980 debris-avalanche deposit were identified, however, and are thought to be caused by viscoelastic relaxation of loosely consolidated substrate, consolidation of water-saturated sediment, or melting of buried ice. Coeruptive interferometric stacks are dominated by atmospheric noise, probably because individual interferograms span only short time intervals in 2004 and 2005. Nevertheless, we are confident that at least one of the seven coeruptive stacks we constructed is reliable at about the 1-cm level. This stack suggests deflation of Mount St. Helens driven by contraction of a source beneath the volcano.

  20. Virtual Investigations of an Active Deep Sea Volcano

    NASA Astrophysics Data System (ADS)

    Sautter, L.; Taylor, M. M.; Fundis, A.; Kelley, D. S.; Elend, M.

    2013-12-01

    Axial Seamount, located on the Juan de Fuca spreading ridge 300 miles off the Oregon coast, is an active volcano whose summit caldera lies 1500 m beneath the sea surface. Ongoing construction of the Regional Scale Nodes (RSN) cabled observatory by the University of Washington (funded by the NSF Ocean Observatories Initiative) has allowed for exploration of recent lava flows and active hydrothermal vents using HD video mounted on the ROVs, ROPOS and JASON II. College level oceanography/marine geology online laboratory exercises referred to as Online Concept Modules (OCMs) have been created using video and video frame-captured mosaics to promote skill development for characterizing and quantifying deep sea environments. Students proceed at their own pace through a sequence of short movies with which they (a) gain background knowledge, (b) learn skills to identify and classify features or biota within a targeted environment, (c) practice these skills, and (d) use their knowledge and skills to make interpretations regarding the environment. Part (d) serves as the necessary assessment component of the laboratory exercise. Two Axial Seamount-focused OCMs will be presented: 1) Lava Flow Characterization: Identifying a Suitable Cable Route, and 2) Assessing Hydrothermal Vent Communities: Comparisons Among Multiple Sulfide Chimneys.

  1. Remote Monitoring of Post-eruption Volcano Environment Based-On Wireless Sensor Network (WSN): The Mount Sinabung Case

    NASA Astrophysics Data System (ADS)

    Soeharwinto; Sinulingga, Emerson; Siregar, Baihaqi

    2017-01-01

    An accurate information can be useful for authorities to make good policies for preventive and mitigation after volcano eruption disaster. Monitoring of environmental parameters of post-eruption volcano provides an important information for authorities. Such monitoring system can be develop using the Wireless Network Sensor technology. Many application has been developed using the Wireless Sensor Network technology, such as floods early warning system, sun radiation mapping, and watershed monitoring. This paper describes the implementation of a remote environment monitoring system of mount Sinabung post-eruption. The system monitor three environmental parameters: soil condition, water quality and air quality (outdoor). Motes equipped with proper sensors, as components of the monitoring system placed in sample locations. The measured value from the sensors periodically sends to data server using 3G/GPRS communication module. The data can be downloaded by the user for further analysis.The measurement and data analysis results generally indicate that the environmental parameters in the range of normal/standard condition. The sample locations are safe for living and suitable for cultivation, but awareness is strictly required due to the uncertainty of Sinabung status.

  2. Long-term autonomous volcanic gas monitoring with Multi-GAS at Mount St. Helens, Washington, and Augustine Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Kelly, P. J.; Ketner, D. M.; Kern, C.; Lahusen, R. G.; Lockett, C.; Parker, T.; Paskievitch, J.; Pauk, B.; Rinehart, A.; Werner, C. A.

    2015-12-01

    In recent years, the USGS Volcano Hazards Program has worked to implement continuous real-time in situ volcanic gas monitoring at volcanoes in the Cascade Range and Alaska. The main goal of this ongoing effort is to better link the compositions of volcanic gases to other real-time monitoring data, such as seismicity and deformation, in order to improve baseline monitoring and early detection of volcanic unrest. Due to the remote and difficult-to-access nature of volcanic-gas monitoring sites in the Cascades and Alaska, we developed Multi-GAS instruments that can operate unattended for long periods of time with minimal direct maintenance from field personnel. Our Multi-GAS stations measure H2O, CO2, SO2, and H2S gas concentrations, are comprised entirely of commercial off-the-shelf components, and are powered by small solar energy systems. One notable feature of our Multi-GAS stations is that they include a unique capability to perform automated CO2, SO2, and H2S sensor verifications using portable gas standards while deployed in the field, thereby allowing for rigorous tracking of sensor performances. In addition, we have developed novel onboard data-processing routines that allow diagnostic and monitoring data - including gas ratios (e.g. CO2/SO2) - to be streamed in real time to internal observatory and public web pages without user input. Here we present over one year of continuous data from a permanent Multi-GAS station installed in August 2014 in the crater of Mount St. Helens, Washington, and several months of data from a station installed near the summit of Augustine Volcano, Alaska in June 2015. Data from the Mount St. Helens Multi-GAS station has been streaming to a public USGS site since early 2015, a first for a permanent Multi-GAS site. Neither station has detected significant changes in gas concentrations or compositions since they were installed, consistent with low levels of seismicity and deformation.

  3. Geothermal exploration philosophy for Mount St. Helens (and other cascade volcanoes)

    SciTech Connect

    Schuster, J.E.; Ruscetta, C.A.; Foley, D.

    1981-05-01

    Factors which hampered geothermal exploration of Cascade stratovolcanoes are listed. What was known about geothermal energy in the Mount Saint Helen's area prior to 1980 and what has been learned as a result of the 1980 eruptions are reviewed. An exploration philosophy is presented. (MHR)

  4. Internal stress field at Mount Vesuvius: A model for background seismicity at a central volcano

    NASA Astrophysics Data System (ADS)

    de Natale, Giuseppe; Petrazzuoli, Stefano M.; Troise, Claudia; Pingue, Folco; Capuano, Paolo

    2000-07-01

    We propose a model to explain the background seismicity occurring at Somma-Vesuvius in its present, mostly quiescent period. A finite element procedure has been used to simulate the stress field due to gravitational body forces in an axisymmetric volcano characterized by a central high-rigidity anomaly. Results emphasize the important effect of axial high-rigidity, which concentrates at its borders stresses resulting from the gravitational load of the volcanic edifice, as well as external (regional) stresses. The joint effect of the gravitational loading and of the presence of the anomaly produces stresses very close to or above the critical rupture threshold. The observed spatial concentrations of seismicity and moment release correlate well with peaks of computed maximum shear stress. Seismicity is then interpreted as due to small stress perturbations concentrated around the high-rigidity core and added to a system already close, to the failure threshold. This model can explain the widely observed occurrence of background seismicity at central volcanoes worldwide.

  5. Amplitude and recurrence time analysis of LP activity at Mount Etna, Italy

    NASA Astrophysics Data System (ADS)

    Cauchie, Léna; Saccorotti, Gilberto; Bean, Christopher J.

    2015-09-01

    The aim of this work is to improve our understanding of the long-period (LP) source mechanism at Mount Etna (Italy) through a statistical analysis of detailed LP catalogues. The behavior of LP activity is compared with the empirical laws governing earthquake recurrence, in order to investigate whether any relationships exist between these two apparently different earthquake classes. We analyzed a family of 8894 events detected during a temporary experiment in August 2005. For that time interval, the LP activity is sustained in time and the volcano did not exhibit any evident sign of unrest. The completeness threshold of the catalogue is established through a detection test based on synthetic waveforms. The retrieved amplitude distribution differs significantly from the Gutenberg-Richter law, and the interevent times distribution does not follow the typical γ law, expected for tectonic activity. In order to compare these results with a catalogue for which the source mechanism is well established, we applied the same procedure to a data set from Stromboli Volcano, where recurrent LP activity is closely related to very-long-period pulses, in turn associated with the summit explosions. Our results indicate that the two catalogues exhibit similar behavior in terms of amplitude and interevent time distributions. This suggests that the Etna's LP signals are most likely driven by stress changes caused by an intermittent degassing process occurring at depth, similar to that which drives the summit explosions at Stromboli Volcano.

  6. Linking subsurface to surface degassing at active volcanoes: A thermodynamic model with applications to Erebus volcano

    NASA Astrophysics Data System (ADS)

    Iacovino, Kayla

    2015-12-01

    Volcanic plumbing systems are the pathways through which volatiles are exchanged between the deep Earth and the atmosphere. The interplay of a multitude of processes occurring at various depths in the system dictates the composition and quantity of gas eventually erupted through volcanic vents. Here, a model is presented as a framework for interpreting surface volcanic gas measurements in terms of subsurface degassing processes occurring throughout a volcanic plumbing system. The model considers all possible sources of fluid from multiple depths, including degassing of dissolved volatiles during crystallization and/or decompression as recorded in melt inclusions plus any co-existing fluid phase present in a magma reservoir. The former is achieved by differencing melt inclusion volatile contents between groups of melt inclusions saturated at discrete depths. The latter is calculated using a thermodynamic model, which computes the composition of a C-O-H-S fluid in equilibrium with a melt given a minimum of five thermodynamic parameters commonly known for natural systems (T, P, fO2, either fH2 or one parameter for H2O, and either fS2 or one parameter for CO2). The calculated fluids are thermodynamically decompressed and run through a mixing model, which finds all possible mixtures of subsurface fluid that match the chemistry of surface gas within ±2.0 mol%. The method is applied to Mount Erebus (Antarctica), an active, intraplate volcano whose gas emissions, which emanate from an active phonolitic lava lake, have been well quantified by FTIR, UV spectroscopy, and multi-gas sensors over the last several decades. In addition, a well-characterized suite of lavas and melt inclusions, and petrological interpretations thereof, represent a wealth of knowledge about the shallow, intermediate, and deep parts of the Erebus plumbing system. The model has been used to calculate the compositions of seven C-O-H-S fluids that originate from four distinct regions within the Erebus

  7. Springs on and in the vicinity of Mount Hood volcano, Oregon

    USGS Publications Warehouse

    Nathenson, Manuel

    2004-01-01

    Chemical and isotopic data are presented for nonthermal, thermal, and slightly thermal springs and drill holes and fumaroles on Mount Hood, Oregon. Temperatures of nonthermal springs on Mount Hood decrease with elevation and are similar to air temperatures from nearby weather stations. Dissolved constituents in nonthermal springs generally increase with spring temperatures and reflect weathering of volcanic rock from the action of dissolved carbon dioxide. Isotopic contents of nonthermal springs follow a local meteoric water line and generally become lighter with elevation. Some nonthermal springs at low-elevation have light values of isotopes indicating a high-elevation source for the water. Three hydrothermal systems have been identified on Mount Hood. Swim Warm Springs is interpreted to have a source water that boiled from 187?C, re-equilibrated at 96?C, and then mixed with nonthermal water to produce the range of compositions found in various springs. The Meadows Spring is interpreted to have a source water that boiled from 223?C, re-equilibrated at 94?C, and then mixed with nonthermal water to produce the range of compositions found in the spring over several years. Both systems contain water that originated as precipitation at higher elevation. The summit fumaroles have gas geothermometer temperatures generally over 300?C, indicating that they are not the steam discharge from the Swim and Meadows hydrothermal systems. Representative values of thermal discharge for the three hydrothermal systems are 10 MWt for the fumaroles, 2.2 MWt for Swim, and 1.9 MWt for the Meadows and Cascade springs.

  8. Revised tephra volumes for Mount St. Helens and Glacier Peak volcanoes

    NASA Astrophysics Data System (ADS)

    Nathenson, M.

    2015-12-01

    Isopach maps from 8 tephra eruptions from Mount St. Helens were reported in Carey et al. (1995) and for 3 eruptions from Glacier Peak in Gardner et al. (1998). These isopach data only define single slopes on a thickness versus square root of area plot (Fierstein and Nathenson, 1992) whereas one expects a second slope in the medial to distal region for larger eruptions. A model was proposed by Carey et al. (1995) for estimating the second slope to calculate volumes. A more recent study by Sulpizio (2005) for estimating the second slope involves a systematic analysis of many eruptions to provide correlation equations. The purpose of this study is to recalculate the volumes of Mount St. Helens and Glacier Peak eruptions and compare results from the two methods for estimating second slopes. In order to gain some perspective on the methods for estimating the second slope, we use data for thickness versus distance beyond the last isopach that is available for some of the eruptions. The thickness versus square root of area method is extended to thickness versus distance by developing an approximate relation between the two, assuming elliptical isopachs. Thickness versus distance data tend to support the Sulpizio method. The volumes derived using the Sulpizio method are 20 % or less of the values for the Mount St. Helens layers given in Carey et al. (1995) and about 50 % of the values for the Glacier Peak layers given in Gardner et al (1998). For example, for Mount St. Helens layer Wn, the volume calculated from the isopachs is 0.55 km3, using the Carey et al. (1995) method it is 7.7 km3, and using the Sulpizio (2005) method it is 1.4 km3. Carey, S., Gardner, J., and Sigurdsson, H., 1995, J. Volc. and Geoth. Res. 66, 185-202. Fierstein, J., and Nathenson, M., 1992, Bull. Volc. 54, 156-167. Gardner, J.E., Carey, S., and Sigurdsson, H., 1998, Geol. Soc. of Am. Bull. 110, 173-187. Sulpizio, R., 2005, J. Volc. Geoth. Res. 145, 315-336.

  9. Rheological properties of mudflows associated with the spring 1980 eruptions of Mount St. Helens volcano, Washington

    SciTech Connect

    Fink, J.H.; Malin, M.C.; D'Alli, R.E.; Greeley, R.

    1981-01-01

    Rhelogoical properties of three recent mudflows at Mount St. Helens were estimated using technique developed for deterimining the properties of debris flows based on the geometry of their deposits. Calculated yield strengths of 1100, 1000, and 400 Pa, maximum flow velocities of 10 to 31 m/s, volumetric flow rates of 300 to 3400 m/sup 3//s, and plastic viscosities of 20 to 320 Ps-s all compare favorably with measured and estimated values cited in the literature. A method for determining likely sites of future mudflow initiation based on these data is outlined.

  10. Benefits of volcano monitoring far outweigh costs - the case of Mount Pinatubo

    USGS Publications Warehouse

    Newhall, Chris G.; Hendley, James W.; Stauffer, Peter H.

    1997-01-01

    The climactic June 1991 eruption of Mount Pinatubo, Philippines, was the largest volcanic eruption in this century to affect a heavily populated area. Because it was forecast by scientists from the Philippine Institute of Volcanology and Seismology and the U.S. Geological Survey, civil and military leaders were able to order massive evacuations and take measures to protect property before the eruption. Thousands of lives were saved and hundreds of millions of dollars in property losses averted. The savings in property alone were many times the total costs of the forecasting and evacuations.

  11. Autonomous thermal camera system for monitoring the active lava lake at Erebus volcano, Antarctica

    NASA Astrophysics Data System (ADS)

    Peters, N.; Oppenheimer, C.; Kyle, P.

    2014-02-01

    In December 2012, the Mount Erebus Volcano Observatory installed a thermal infrared camera system to monitor the volcano's active lava lake. The new system is designed to be autonomous, and capable of capturing images of the lava lake continuously throughout the year. This represents a significant improvement over previous systems which required the frequent attention of observatory researchers and could therefore only be operated during a few weeks of the annual field campaigns. The extreme environmental conditions at the summit of Erebus pose significant challenges for continuous monitoring equipment, and a custom-made system was the only viable solution. Here we describe the hardware and software of the new system in detail and report on a publicly available online repository where data will be archived. Aspects of the technical solutions we had to find in order to overcome the challenges of automating this equipment may be relevant in other environmental science domains where remote instrument operation is involved.

  12. Autonomous thermal camera system for monitoring the active lava lake at Erebus volcano, Antarctica

    NASA Astrophysics Data System (ADS)

    Peters, N.; Oppenheimer, C.; Kyle, P.

    2013-10-01

    In December 2012, the Mount Erebus Volcano Observatory installed a thermal infrared camera system to monitor the volcano's active lava lake. The new system is designed to be autonomous, and capable of capturing images of the lava lake continuously throughout the year. This represents a significant improvement over previous systems which required the frequent attention of observatory researchers and could therefore only be operated during a few weeks of the annual field campaigns. The extreme environmental conditions at the summit of Erebus pose significant challenges for continuous monitoring equipment, and a custom made system was the only viable solution. Here we describe the hardware and software of the new system in detail and report on a publicly-available online repository where data will be archived. Aspects of the technical solutions we had to find in order to overcome the challenges of automating this equipment may be relevant in other environmental science domains where remote instrument operation is involved.

  13. Spatial variations in the frequency-magnitude distribution of earthquakes at Mount Pinatubo volcano

    USGS Publications Warehouse

    Sanchez, J.J.; McNutt, S.R.; Power, J.A.; Wyss, M.

    2004-01-01

    The frequency-magnitude distribution of earthquakes measured by the b-value is mapped in two and three dimensions at Mount Pinatubo, Philippines, to a depth of 14 km below the summit. We analyzed 1406 well-located earthquakes with magnitudes MD ???0.73, recorded from late June through August 1991, using the maximum likelihood method. We found that b-values are higher than normal (b = 1.0) and range between b = 1.0 and b = 1.8. The computed b-values are lower in the areas adjacent to and west-southwest of the vent, whereas two prominent regions of anomalously high b-values (b ??? 1.7) are resolved, one located 2 km northeast of the vent between 0 and 4 km depth and a second located 5 km southeast of the vent below 8 km depth. The statistical differences between selected regions of low and high b-values are established at the 99% confidence level. The high b-value anomalies are spatially well correlated with low-velocity anomalies derived from earlier P-wave travel-time tomography studies. Our dataset was not suitable for analyzing changes in b-values as a function of time. We infer that the high b-value anomalies around Mount Pinatubo are regions of increased crack density, and/or high pore pressure, related to the presence of nearby magma bodies.

  14. Thrust faults and related structures in the crater floor of Mount St. Helens volcano, Washington

    USGS Publications Warehouse

    Chadwick, W.W.; Swanson, D.A.

    1989-01-01

    A lava dome was built in the crater of Mount St. Helens by intermittent intrusion and extrusion of dacite lava between 1980 and 1986. Spectacular ground deformation was associated with the dome-building events and included the development of a system of radial cracks and tangential thrust faults in the surrounding crater floor. These cracks and thrusts, best developed and studied in 1981-1982, formed first and, as some evolved into strike-slip tear faults, influenced the subsequent geometry of thrusting. Once faulting began, deformation was localized near the thrust scarps and their bounding tear faults. The magnitude of displacements systematically increased before extrusions, whereas the azimuth and inclination of displacements remained relatively constant. The thrust-fault scarps were bulbous in profile, lobate in plan, and steepened during continued fault movement. The hanging walls of each thrust were increasingly disrupted as cumulative fault slip increased. -from Authors

  15. Summit crater lake observations, and the location, chemistry, and pH of water samples near Mount Chiginagak volcano, Alaska: 2004-2012

    USGS Publications Warehouse

    Schaefer, Janet R.; Scott, William E.; Evans, William C.; Wang, Bronwen; McGimsey, Robert G.

    2013-01-01

    Mount Chiginagak is a hydrothermally active volcano on the Alaska Peninsula, approximately 170 km south–southwest of King Salmon, Alaska (fig. 1). This small stratovolcano, approximately 8 km in diameter, has erupted through Tertiary to Permian sedimentary and igneous rocks (Detterman and others, 1987). The highest peak is at an elevation of 2,135 m, and the upper ~1,000 m of the volcano are covered with snow and ice. Holocene activity consists of debris avalanches, lahars, and lava flows. Pleistocene pyroclastic flows and block-and-ash flows, interlayered with andesitic lava flows, dominate the edifice rocks on the northern and western flanks. Historical reports of activity are limited and generally describe “steaming” and “smoking” (Coats, 1950; Powers, 1958). Proximal tephra collected during recent fieldwork suggests there may have been limited Holocene explosive activity that resulted in localized ash fall. A cluster of fumaroles on the north flank, at an elevation of ~1,750 m, commonly referred to as the “north flank fumarole” have been emitting gas throughout historical time (location shown in fig. 2). The only other thermal feature at the volcano is the Mother Goose hot springs located at the base of the edifice on the northwestern flank in upper Volcano Creek, at an elevation of ~160 m (fig. 2, near sites H1, H3, and H4). Sometime between November 2004 and May 2005, a ~400-m-wide, 100-m-deep lake developed in the snow- and ice-filled summit crater of the volcano (Schaefer and others, 2008). In early May 2005, an estimated 3 million cubic meters (3×106 m3) of sulfurous, clay-rich debris and acidic water exited the crater through tunnels at the base of a glacier that breaches the south crater rim. More than 27 km downstream, these acidic flood waters reached approximately 1.3 m above normal water levels and inundated a fertile, salmon-spawning drainage, acidifying the entire water column of Mother Goose Lake from its surface waters to its

  16. Climate influence on volcano edifice stability and fluvial landscape evolution surrounding Mount Ruapehu, New Zealand

    NASA Astrophysics Data System (ADS)

    Tost, M.; Cronin, S. J.

    2016-06-01

    Large volcanic debris avalanches are triggered by failure of the steep flanks of long-lived composite cones. Their huge deposits change the landscape and drainage pattern surrounding stratovolcanoes for thousands of years. At Mt. Ruapehu, New Zealand, we identified seven major flank-collapse events that produced debris avalanches travelling down pre-existing river catchments for up to 90 km from source. In two cases the extreme mass flux into the river valleys led to their complete truncation from the volcano, while four drainage systems were subsequently re-established along similar pathways influenced by regional strike-slip faulting, which caused localized graben formation. In all cases the volcanic debris-avalanche deposits currently form distinctive plateaus at or near the highest topographic elevations of each river valley margin. The timing of the flank failures indicate that inter-eruptive cone destabilization of Mt. Ruapehu is affected by climate change and occurs most commonly during interstadials when glaciers on the cone are in retreat, whereas syn-eruptive collapses are most prominent during cold stages. Dated debris-avalanche deposit levels, along with those of up to four stadial-related aggradational gravel terraces between c. 125 and 18 ka, were used to calculate regional uplift rates in this area. Rates of between 0.2 ± 0.1 mm yr- 1 to 3.8 ± 0.8 mm yr- 1 are found for four river systems dissecting the central North Island of New Zealand. In three cases incision below the diamicton sequences and into the basement, allowed quantification of sediment-flux rates into the Tasman Sea of 107,000 ± 1,200 m3 yr- 1 to 177,000 ± 3,500 m3 yr- 1 since debris-avalanche emplacement.

  17. Generation of pyroclastic flows and surges by hot-rock avalanches from the dome of Mount St. Helens volcano, USA

    USGS Publications Warehouse

    Mellors, R.A.; Waitt, R.B.; Swanson, D.A.

    1988-01-01

    Several hot-rock avalanches have occurred during the growth of the composite dome of Mount St. Helens, Washington between 1980 and 1987. One of these occurred on 9 May 1986 and produced a fan-shaped avalanche deposit of juvenile dacite debris together with a more extensive pyroclastic-flow deposit. Laterally thinning deposits and abrasion and baking of wooden and plastic objects show that a hot ash-cloud surge swept beyond the limits of the pyroclastic flow. Plumes that rose 2-3 km above the dome and vitric ash that fell downwind of the volcano were also effects of this event, but no explosion occurred. All the facies observed originated from a single avalanche. Erosion and melting of craterfloor snow by the hot debris caused debris flows in the crater, and a small flood that carried juvenile and other clasts north of the crater. A second, broadly similar event occured in October 1986. Larger events of this nature could present a significant volcanic hazard. ?? 1988 Springer-Verlag.

  18. Broadband characteristics of earthquakes recorded during a dome-building eruption at Mount St. Helens, Washington, between October 2004 and May 2005: Chapter 5 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Horton, Stephen P.; Norris, Robert D.; Moran, Seth C.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    From October 2004 to May 2005, the Center for Earthquake Research and Information of the University of Memphis operated two to six broadband seismometers within 5 to 20 km of Mount St. Helens to help monitor recent seismic and volcanic activity. Approximately 57,000 earthquakes identified during the 7-month deployment had a normal magnitude distribution with a mean magnitude of 1.78 and a standard deviation of 0.24 magnitude units. Both the mode and range of earthquake magnitude and the rate of activity varied during the deployment. We examined the time domain and spectral characteristics of two classes of events seen during dome building. These include volcano-tectonic earthquakes and lower-frequency events. Lower-frequency events are further classified into hybrid earthquakes, low-frequency earthquakes, and long-duration volcanic tremor. Hybrid and low-frequency earthquakes showed a continuum of characteristics that varied systematically with time. A progressive loss of high-frequency seismic energy occurred in earthquakes as magma approached and eventually reached the surface. The spectral shape of large and small earthquakes occurring within days of each other did not vary with magnitude. Volcanic tremor events and lower-frequency earthquakes displayed consistent spectral peaks, although higher frequencies were more favorably excited during tremor than earthquakes.

  19. Fumarole emissions at Mount St. Helens volcano, June 1980 to October 1981: Degassing of a magma-hydrothermal system

    USGS Publications Warehouse

    Gerlach, T.M.; Casadevall, T.J.

    1986-01-01

    This study is an investigation of the chemical changes in the Mount St. Helens fumarole gases up to October 1981, the sources of the fumarole gases, and the stability of gas species in the shallow magma system. These problems are investigated by calculations of element compositions, thermodynamic equilibria, and magmatic volatile-hydrothermal steam mixing models. The fumarole gases are treated as mixtures of magmatic volatiles and hydrothermal steam formed by magma degassing and boiling of local waters in a dryout zone near conduit and dome magma. The magmatic volatile fraction is significant in fumaroles with temperatures in excess of the magma cracking-temperature (??? 700??C) - i.e., the temperature below which cracking is induced by thermal stresses during cooling and solidification. Linear composition changes of the fumarole gases over time appear to be the result of a steady decline in the magmatic volatile mixing fraction, which may be due to the tapping of progressively volatile-depleted magma. The maximum proportion of hydrothermal steam in the fumaroles rose from about 25-35% in September 1980 to around 50-70% by October 1981. Fractional degassing of magmatic CO2 and sulfur also contributed to the chemical changes in the fumarole gases. The steady chemical changes indicate that replenishment of the magma system with undegassed magma was not significant between September 1980 and September 1981. Extrapolations of chemical trends suggest that fumarole gases emitted at the time of formation of the first dome in mid-June 1980 were more enriched in a magmatic volatile fraction and contained a minimum of 9% CO2. Calculations show H2S is the predominant sulfur species in Mount St. Helens magma below depths of 200 m. Rapid release of gases from magma below this depth is a plausible mechanism for producing the high H2S/SO2 observed in Mount St. Helens plumes during explosive eruptions. This study suggests that dacite-andesite volcanos may emit gases richer in CO2

  20. Fumarole emissions at Mount St. Helens volcano, June 1980 to October 1981: Degassing of a magma-hydrothermal system

    NASA Astrophysics Data System (ADS)

    Gerlach, Terrence M.; Casadevall, Thomas J.

    1986-05-01

    This study is an investigation of the chemical changes in the Mount St. Helens fumarole gases up to October 1981, the sources of the fumarole gases, and the stability of gas species in the shallow magma system. These problems are investigated by calculations of element compositions, thermodynamic equilibria, and magmatic volatile—hydrothermal steam mixing models. The fumarole gases are treated as mixtures of magmatic volatiles and hydrothermal steam formed by magma degassing and boiling of local waters in a dryout zone near conduit and dome magma. The magmatic volatile fraction is significant in fumaroles with temperatures in excess of the magma cracking-temperature (˜ 700°C) — i.e., the temperature below which cracking is induced by thermal stresses during cooling and solidification. Linear composition changes of the fumarole gases over time appear to be the result of a steady decline in the magmatic volatile mixing fraction, which may be due to the tapping of progressively volatile-depleted magma. The maximum proportion of hydrothermal steam in the fumaroles rose from about 25-35% in September 1980 to around 50-70% by October 1981. Fractional degassing of magmatic CO 2 and sulfur also contributed to the chemical changes in the fumarole gases. The steady chemical changes indicate that replenishment of the magma system with undegassed magma was not significant between September 1980 and September 1981. Extrapolations of chemical trends suggest that fumarole gases emitted at the time of formation of the first dome in mid-June 1980 were more enriched in a magmatic volatile fraction and contained a minimum of 9% CO 2. Calculations show H 2S is the predominant sulfur species in Mount St. Helens magma below depths of 200 m. Rapid release of gases from magma below this depth is a plausible mechanism for producing the high H 2S/SO 2 observed in Mount St. Helens plumes during explosive eruptions. This study suggests that dacite-andesite volcanos may emit gases richer

  1. Mount Rainier: living with perilous beauty

    USGS Publications Warehouse

    Scott, Kevin M.; Wolfe, Edward W.; Driedger, Carolyn L.

    1998-01-01

    Mount Rainier is an active volcano reaching more than 2.7 miles (14,410 feet) above sea level. Its majestic edifice looms over expanding suburbs in the valleys that lead to nearby Puget Sound. USGS research over the last several decades indicates that Mount Rainier has been the source of many volcanic mudflows (lahars) that buried areas now densely populated. Now the USGS is working cooperatively with local communities to help people live more safely with the volcano.

  2. Measuring thermal budgets of active volcanoes by satellite remote sensing

    NASA Technical Reports Server (NTRS)

    Glaze, L.; Francis, P. W.; Rothery, D. A.

    1989-01-01

    Thematic Mapper measurements of the total radiant energy flux Q at Lascar volcano in north Chile for December 1984 are reported. The results are consistent with the earlier suggestion that a lava lake is the source of a reported thermal budget anomaly, and with values for 1985-1986 that are much lower, suggesting that fumarolic activity was then a more likely heat source. The results show that satellite remote sensing may be used to monitor the activity of a volcano quantitatively, in a way not possible by conventional ground studies, and may provide a method for predicting eruptions.

  3. Determining the stress field in active volcanoes using focal mechanisms

    NASA Astrophysics Data System (ADS)

    Massa, Bruno; D'Auria, Luca; Cristiano, Elena; De Matteo, Ada

    2016-11-01

    Stress inversion of seismological datasets became an essential tool to retrieve the stress field of active tectonics and volcanic areas. In particular, in volcanic areas, it is able to put constrains on volcano-tectonics and in general in a better understanding of the volcano dynamics. During the last decades, a wide range of stress inversion techniques has been proposed, some of them specifically conceived to manage seismological datasets. A modern technique of stress inversion, the BRTM, has been applied to seismological datasets available at three different regions of active volcanism: Mt. Somma-Vesuvius (197 Fault Plane Solutions, FPSs), Campi Flegrei (217 FPSs) and Long Valley Caldera (38,000 FPSs). The key role of stress inversion techniques in the analysis of the volcano dynamics has been critically discussed. A particular emphasis was devoted to performances of the BRTM applied to volcanic areas.

  4. Mount St. Helens Classroom Activities: Secondary.

    ERIC Educational Resources Information Center

    Washington State Educational Service District 112, Vancouver.

    This teacher's guide is designed to provide secondary teachers with an assortment of classroom activities dealing with the Mt. St. Helens eruption of May 18, 1980, in the areas of science, social studies, math, language arts and school newspaper activities. Copy masters and teacher versions of all activities are contained within this guide,…

  5. Mount St. Helens Classroom Activities: Elementary.

    ERIC Educational Resources Information Center

    Washington State Educational Service District 112, Vancouver.

    This teacher's guide is designed to provide elementary teachers with an assortment of classroom activities dealing with the Mt. St. Helens eruption of May 18, 1980, in the areas of science, social studies, math, language arts, and school newspaper activities. Copy masters and teacher versions of all activities are contained with this guide,…

  6. Output rate of magma from active central volcanoes

    NASA Technical Reports Server (NTRS)

    Wadge, G.

    1980-01-01

    For part of their historic records, nine of the most active volcanoes on earth have each erupted magma at a nearly constant rate. These output rates are very similar and range from 0.69 to 0.26 cu m/s. The volcanoes discussed - Kilauea, Mauna Loa, Fuego, Santiaguito, Nyamuragira, Hekla, Piton de la Fournaise, Vesuvius and Etna - represent almost the whole spectrum of plate tectonic settings of volcanism. A common mechanism of buoyantly rising magma-filled cracks in the upper crust may contribute to the observed restricted range of the rates of output.

  7. Long-term eruptive activity at a submarine arc volcano

    USGS Publications Warehouse

    Embley, R.W.; Chadwick, W.W.; Baker, E.T.; Butterfield, D.A.; Resing, J.A.; De Ronde, C. E. J.; Tunnicliffe, V.; Lupton, J.E.; Juniper, S.K.; Rubin, K.H.; Stern, R.J.; Lebon, G.T.; Nakamura, K.-I.; Merle, S.G.; Hein, J.R.; Wiens, D.A.; Tamura, Y.

    2006-01-01

    Three-quarters of the Earth's volcanic activity is submarine, located mostly along the mid-ocean ridges, with the remainder along intraoceanic arcs and hotspots at depths varying from greater than 4,000 m to near the sea surface. Most observations and sampling of submarine eruptions have been indirect, made from surface vessels or made after the fact. We describe here direct observations and sampling of an eruption at a submarine arc volcano named NW Rota-1, located 60 km northwest of the island of Rota (Commonwealth of the Northern Mariana Islands). We observed a pulsating plume permeated with droplets of molten sulphur disgorging volcanic ash and lapilli from a 15-m diameter pit in March 2004 and again in October 2005 near the summit of the volcano at a water depth of 555 m (depth in 2004). A turbid layer found on the flanks of the volcano (in 2004) at depths from 700 m to more than 1,400 m was probably formed by mass-wasting events related to the eruption. Long-term eruptive activity has produced an unusual chemical environment and a very unstable benthic habitat exploited by only a few mobile decapod species. Such conditions are perhaps distinctive of active arc and hotspot volcanoes. ?? 2006 Nature Publishing Group.

  8. Seismic Activity at Vailulu'u, Samoa's Youngest Volcano

    NASA Astrophysics Data System (ADS)

    Konter, J.; Staudigel, H.; Hart, S.

    2002-12-01

    Submarine volcanic systems, as a product of the Earth's mantle, play an essential role in the Earth's heat budget and in the interaction between the solid Earth and the hydrosphere and biosphere. Their eruptive and intrusive activity exerts an important control on these hydrothermal systems. In March 2000, we deployed an array of five ocean bottom hydrophones (OBH) on the summit region (625-995 m water depth) of Vailulu'u Volcano (14°12.9'S;169°03.5'W); this volcano represents the active end of the Samoan hotspot chain and is one of only a few well-studied intra-plate submarine volcanoes. We monitored seismic activity for up to 12 months at low sample rate (25 Hz), and for shorter times at a higher sample rate (125 Hz). We have begun to catalogue and locate a variety of acoustic events from this network. Ambient ocean noise was filtered out by a 4th-order Butterworth bandpass filter (2.3 - 10 Hz). We distinguish small local earthquakes from teleseismic activity, mostly identified by T- (acoustic) waves, by comparison with a nearby GSN station (AFI). Most of the detected events are T-phases from teleseismic earthquakes, characterized by their emergent coda and high frequency content (up to 30 Hz); the latter distinguishes them from low frequency emergent signals associated with the volcano (e.g. tremor). A second type of event is characterized by impulsive arrivals, with coda lasting a few seconds. The differences in arrival times between stations on the volcano are too small for these events to be T-waves; they are very likely to be local events, since the GSN station in Western Samoa (AFI) shows no arrivals close in time to these events. Preliminary locations show that these small events occur approximately once per day and are located within the volcano (the 95% confidence ellipse is similar to the size of the volcano, due to the small size of the OBH network). Several events are located relatively close to each other (within a km radius) just NW of the crater.

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

    NASA Astrophysics Data System (ADS)

    Konstantinou, Konstantinos I.; Lin, Cheng-Horng; Liang, Wen-Tzong

    2007-02-01

    The Tatun Volcano Group (TVG) is located at the northern tip of Taiwan, near the capital Taipei and close to two nuclear power plants. Because of lack of any activity in historical times it has been classified as an extinct volcano, even though more recent studies suggest that TVG might have been active during the last 20 ka. In May 2003 a seismic monitoring project at the TVG area was initiated by deploying eight three-component seismic stations some of them equipped with both short-period and broadband sensors. During the 18 months observation period local seismicity mainly consisted of high frequency earthquakes either occurring as isolated events, or as a continuous sequence in the form of spasmodic bursts. Mixed and low frequency events were also present during the same period, even though they occurred only rarely. Arrival times from events with clear P-/S-wave phases were inverted in order to obtain a minimum 1D velocity model with station corrections. Probabilistic nonlinear earthquake locations were calculated for all these events using the newly derived velocity model. Most high frequency seismicity appeared to be concentrated near the areas of hydrothermal activity, forming tight clusters at depths shallower than 4 km. Relative locations, calculated using the double-difference method and utilising catalogue and cross-correlation differential traveltimes, showed insignificant differences when compared to the nonlinear probabilistic locations. In general, seismicity in the TVG area seems to be primarily driven by circulation of hydrothermal fluids as indicated by the occurrence of spasmodic bursts, mixed/low frequency events and a b-value (1.17 ± 0.1) higher than in any other part of Taiwan. These observations, that are similar to those reported in other dormant Quaternary volcanoes, indicate that a magma chamber may still exist beneath TVG and that a future eruption or period of unrest should not be considered unlikely.

  10. The borehole dilatometer network of Mount Etna: A powerful tool to detect and infer volcano dynamics

    NASA Astrophysics Data System (ADS)

    Bonaccorso, A.; Linde, A.; Currenti, G.; Sacks, S.; Sicali, A.

    2016-06-01

    A network of four borehole dilatometers has been installed on Etna in two successive phases (2010-2011 and 2014). The borehole dilatometers are installed in holes drilled at depths usually greater than 100 m, and they measure the volumetric strain of the surrounding rock with a nominal precision up to 10-11 in a wide frequency range (10-7-25 Hz). Here we describe the characteristics of the network and the results of the in situ calibrations obtained after the installations by different methods. We illustrate short-term strain changes recorded during several lava fountains erupted by Etna during 2011-2013, and we also show signal changes recorded at all four stations during the lava fountain on 28 December 2014. Analytical and numerical computations constrained the eruptions source depth and also its volume change that is related to the magma volume emitted. Finally, we show the potential of the signal in the medium term to reveal strain changes related to different phases of the volcanic activity.

  11. GlobVolcano pre-operational services for global monitoring active volcanoes

    NASA Astrophysics Data System (ADS)

    Tampellini, Lucia; Ratti, Raffaella; Borgström, Sven; Seifert, Frank Martin; Peltier, Aline; Kaminski, Edouard; Bianchi, Marco; Branson, Wendy; Ferrucci, Fabrizio; Hirn, Barbara; van der Voet, Paul; van Geffen, J.

    2010-05-01

    The GlobVolcano project (2007-2010) is part of the Data User Element programme of the European Space Agency (ESA). The project aims at demonstrating Earth Observation (EO) based integrated services to support the Volcano Observatories and other mandate users (e.g. Civil Protection) in their monitoring activities. The information services are assessed in close cooperation with the user organizations for different types of volcano, from various geographical areas in various climatic zones. In a first phase, a complete information system has been designed, implemented and validated, involving a limited number of test areas and respective user organizations. In the currently on-going second phase, GlobVolcano is delivering pre-operational services over 15 volcanic sites located in three continents and as many user organizations are involved and cooperating with the project team. The set of GlobVolcano offered EO based information products is composed as follows: Deformation Mapping DInSAR (Differential Synthetic Aperture Radar Interferometry) has been used to study a wide range of surface displacements related to different phenomena (e.g. seismic faults, volcanoes, landslides) at a spatial resolution of less than 100 m and cm-level precision. Permanent Scatterers SAR Interferometry method (PSInSARTM) has been introduced by Politecnico of Milano as an advanced InSAR technique capable of measuring millimetre scale displacements of individual radar targets on the ground by using multi-temporal data-sets, estimating and removing the atmospheric components. Other techniques (e.g. CTM) have followed similar strategies and have shown promising results in different scenarios. Different processing approaches have been adopted, according to data availability, characteristic of the area and dynamic characteristics of the volcano. Conventional DInSAR: Colima (Mexico), Nyiragongo (Congo), Pico (Azores), Areanal (Costa Rica) PSInSARTM: Piton de la Fournaise (La Reunion Island

  12. Volcano acoustic activity associated with the eruption of Mt. Usu, 2000 - Mud-pool Strombolian -

    NASA Astrophysics Data System (ADS)

    Aoyama, H.; Oshima, H.; Maekawa, T.

    2001-12-01

    There was intense acoustic activity associated with the eruption of Mount Usu, which began on March 31, 2000. Repeating phreatic explosions generated many isolated infrasonic signals, which were observed at plural acoustic stations. During the periods when acoustic activity was high, infrasonic pulses as many as 200 were identified every 10 minutes. Source location of infrasonic signals could be well identified from the records of the low frequency microphone network. Two active craters, Nishiyama craterlets and Konpirayama craterlets, are clearly distinguished by sound source determination analysis though distance between them is around 1 km. To investigate the transition of acoustic activity from April to June, 2000, we contrive a method to detect arrival and amplitude of infrasonic signals automatically. The number of automatically identified infrasonic signals exceeds 1.46 million during three months. It seems that there is a good correlation between acoustic activity and seismic signal amplitude. Patterns of acoustic activity and infrasonic pulse shapes observed at Usu volcano are very similar to those of observed at Stromboli volcano, Italy. We name the acoustic activity accompanied with phreatic explosion that scatters a lot of clods `mud-pool Strombolian type'. Phreatic explosion excites not only infrasonic pulse but also seismic signal observed before the arrival of infrasonic pulse. Existence of Rayleigh wave phase with large amplitude suggests that the seismic wave is excited at a shallow part.

  13. Constraints and conundrums resulting from ground-deformation measurements made during the 2004-2005 dome-building eruption of Mount St. Helens, Washington: Chapter 14 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Dzurisin, Daniel; Lisowski, Michael; Poland, Michael P.; Sherrod, David R.; LaHusen, Richard G.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    Lack of precursory inflation suggests that the volcano was poised to erupt magma already stored in a crustal reservoir when JRO1 was installed in 1997. Trilateration and campaign GPS data indicate surface dilatation, presumably caused by reservoir expansion between 1982 and 1991, but no measurable deformation between 1991 and 2003. We conclude that all three of the traditionally reliable eruption precursors (seismicity, ground deformation, and volcanic gas emission) failed to provide warning that an eruption was imminent until a few days before a visible welt appeared at the surface--a situation reminiscent of the 1980 north-flank bulge at Mount St. Helens.

  14. If You Don't Have a Good Laboratory, Find a Good Volcano: Mount Vesuvius as a Natural Chemical Laboratory in Eighteenth-Century Italy.

    PubMed

    Guerra, Corinna

    2015-08-01

    This essay that examines the role of the volcano as a chemical site in the late eighteenth century, as the "new chemistry" spread throughout the southern Italian Kingdom of Naples, resulting in lively debates. In Naples itself, these scientific debates were not confined to academies, courts, and urban spaces. In the absence of well-equipped chemical laboratories, Neapolitan scholars also carried out research on chemistry on the slopes of Mount Vesuvius, a natural site that furnished them with all the tools and substances necessary for practising chemistry. By examining various Neapolitan publications on Vesuvius and the chemical reactions and products associated with its periodic eruptions, I argue that the volcano's presence contributed to a distinctive, local approach to chemical theory and practice. Several case studies examine the ways in which proximity to Vesuvius was exploited by Neapolitan scholars as they engaged with the new chemistry, including Giuseppe Vairo, Michele Ferrara, Francesco Semmola, and Emanuele Scotti.

  15. 2011 volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Maharrey, J. Zebulon; Neal, Christina A.

    2014-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, and volcanic unrest at or near three separate volcanic centers in Alaska during 2011. The year was highlighted by the unrest and eruption of Cleveland Volcano in the central Aleutian Islands. AVO annual summaries no longer report on activity at Russian volcanoes.

  16. Measurements of slope distances and vertical angles at Mount Baker and Mount Rainier, Washington, Mount Hood and Crater Lake, Oregon, and Mount Shasta and Lassen Peak, California, 1980-1984

    USGS Publications Warehouse

    Chadwick, W.W.

    1985-01-01

    Personnel of the U.S.Geological Survey's Cascades Volcano Observatory established trilateration networks at Mount Baker, Mount Rainier, Mount Hood, Crater Lake, Mount Shasta, and Lassen Peak in 1980-1984. These networks are capable of detecting changes in slope distance of several centimeters or more. The networks were established to provide baseline information on potentially active volcanoes and were designed along guidelines found useful at Mount St. Helens. Periodic reoccupation of the networks is planned as part of the overall monitoring program of Cascades volcanoes. Methodology, slope distance and vertical angle data, maps of the networks, and benchmark descriptions are presented in this report. Written benchmark descriptions are augmented by photographs, which we have found by experience to very useful in relocating the marks. All repeat measurements at the six volcanoes are probably within measurement error.

  17. Photogeologic maps of the 2004-2005 Mount St. Helens eruption: Chapter 10 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Herriott, Trystan M.; Sherrod, David R.; Pallister, John S.; Vallance, James W.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    The 2004-5 eruption of Mount St. Helens, still ongoing as of this writing (September 2006), has comprised chiefly lava dome extrusion that produced a series of solid, faultgouge-mantled dacite spines. Vertical aerial photographs taken every 2 to 4 weeks, visual observations, and oblique photographs taken from aircraft and nearby observation points provide the basis for two types of photogeologic maps of the dome--photo-based maps and rectified maps. Eight map pairs, covering the period from October 1, 2004, through December 15, 2005, document the development of seven spines: an initial small, fin-shaped vertical spine; a north-south elongate wall of dacite; two large and elongate recumbent spines (“whalebacks”); a tall and elongate inclined spine; a smaller bulbous spine; and an initially endogenous spine extruded between remnants of preceding spines. All spines rose from the same general vent area near the southern margin of the 1980s lava dome. Maps also depict translation and rotation of active and abandoned spines, progressive deformation affecting Crater Glacier, and distribution of ash on the crater floor from phreatic and phreatomagmatic explosions. The maps help track key geologic and geographic features in the rapidly changing crater and help date dome, gouge, and ash samples that are no longer readily correlated to their original context because of deformation in a dynamic environment where spines extrude, deform, slough, and are overrun by newly erupted material.

  18. Observing active deformation of volcanoes in North America: Geodetic data from the Plate Boundary Observatory and associated networks

    NASA Astrophysics Data System (ADS)

    Puskas, C. M.; Phillips, D. A.; Mattioli, G. S.; Meertens, C. M.; Hodgkinson, K. M.; Crosby, C. J.; Enders, M.; Feaux, K.; Mencin, D.; Baker, S.; Lisowski, M.; Smith, R. B.

    2013-12-01

    The EarthScope Plate Boundary Observatory (PBO), operated by UNAVCO, records deformation of the geologically diverse North America western plate boundary, with subnetworks of instruments concentrated at selected active and potentially active volcanoes. These sensors record deformation and earthquakes and allow monitoring agencies and researchers to analyze changes in ground motion and seismicity. The intraplate volcanoes at Yellowstone and Long Valley are characterized by uplift/subsidence cycles, high seismicity, and hydrothermal activity but there have been no historic eruptions at either volcano. PBO maintains dense GPS networks of 20-25 stations at each of these volcanoes, with an additional 5 boreholes at Yellowstone containing tensor strainmeters, short-period seismometers, and borehole tiltmeters. Subduction zone volcanoes in the Aleutian Arc have had multiple historic eruptions, and PBO maintains equipment at Augustine (8 GPS), Akutan (8 GPS, 4 tiltmeters), and Unimak Island (14 GPS, 8 tiltmeters). The Unimak stations are at the active Westdahl and Shishaldin edifices and the nearby, inactive Isanotski volcano. In the Cascade Arc, PBO maintains networks at Mount St. Helens (15 GPS, 4 borehole strainmeters and seismometers, 8 borehole tiltmeters), Shasta (7 GPS, 1 borehole strainmeter and seismometer), and Lassen Peak (8 GPS). Data from many of these stations in the Pacific Northwest and California are also provided as realtime streams of raw and processed data. Real-time GPS data, along with high-rate GPS data, will be an important new resource for detecting and studying future rapid volcanic deformation events and earthquakes. UNAVCO works closely with the USGS Volcano Hazards Program, archiving data from USGS GPS stations in Alaska, Cascadia, and Long Valley. The PBO and USGS networks combined provide more comprehensive coverage than PBO alone, particularly of the Cascade Arc, where the USGS maintains a multiple instruments near each volcano. Ground

  19. How a complex basaltic volcanic system works: Constraints from integrating seismic, geodetic, and petrological data at Mount Etna volcano during the July-August 2014 eruption

    NASA Astrophysics Data System (ADS)

    Viccaro, Marco; Zuccarello, Francesco; Cannata, Andrea; Palano, Mimmo; Gresta, Stefano

    2016-08-01

    Integrating geodetic, seismic, and petrological data for a recent eruptive episode at Mount Etna has enabled us to define the history of magma storage and transfer within the multilevel structure of the volcano, providing spatial and temporal constraints for magma movements before the eruption. Geodetic data related to the July-August 2014 activity provide evidence of a magma reservoir at ~4 km below sea level. This reservoir pressurized from late March 2014 and fed magmas that were then erupted from vents on the lower eastern flank of North-East Crater (NEC) and at New South-East Crater (NSEC) summit crater during the July eruptive activity. Magma drainage caused its depressurization since mid-July. Textural and microanalytical data obtained from plagioclase crystals indicate similar disequilibrium textures and compositions at the cores in lavas erupted at the base of NEC and NSEC, suggesting comparable deep histories of evolution and ascent. Conversely, the compositional differences observed at the crystal rims have been associated to distinct degassing styles during storage in a shallow magma reservoir. Seismic data have constrained depth for a shallow part of the plumbing system at 1-2 km above sea level. Timescales of magma storage and transfer have also been calculated through diffusion modeling of zoning in olivine crystals of the two systems. Our data reveal a common deep history of magmas from the two systems, which is consistent with a recharging phase by more mafic magma between late March and early June 2014. Later, the magma continued its crystallization under distinct chemical and physical conditions at shallower levels.

  20. Continuous gravity observations at active volcanoes through superconducting gravimeters

    NASA Astrophysics Data System (ADS)

    Carbone, Daniele; Greco, Filippo

    2016-04-01

    Continuous gravity measurements at active volcanoes are usually taken through spring gravimeters that are easily portable and do not require much power to work. However, intrinsic limitations dictate that, when used in continuous, these instruments do not provide high-quality data over periods longer than some days. Superconducting gravimeters (SG), that feature a superconducting sphere in a magnetic field as the proof mass, provide better-quality data than spring gravimeters, but are bigger and need mains electricity to work, implying that they cannot be installed close to the active structures of high volcanoes. An iGrav SG was installed on Mt. Etna (Italy) in September 2014 and has worked almost continuously since then. It was installed about 6km from the active craters in the summit zone of the volcano. Such distance is normally too much to observe gravity changes due to relatively fast (minutes to days) volcanic processes. Indeed, mass redistributions in the shallowest part of the plumbing system induce short-wavelength gravity anomalies, centered below the summit craters. Nevertheless, thanks to the high precision and long-term stability of SGs, it was possible to observe low-amplitude changes over a wide range of timescales (minutes to months), likely driven by volcanic activity. Plans are in place for the implementation of a mini-array of SGs at Etna.

  1. Monitoring eruptive activity at Mount St. Helens with TIR image data

    USGS Publications Warehouse

    Vaughan, R.G.; Hook, S.J.; Ramsey, M.S.; Realmuto, V.J.; Schneider, D.J.

    2005-01-01

    Thermal infrared (TIR) data from the MASTER airborne imaging spectrometer were acquired over Mount St. Helens in Sept and Oct, 2004, before and after the onset of recent eruptive activity. Pre-eruption data showed no measurable increase in surface temperatures before the first phreatic eruption on Oct 1. MASTER data acquired during the initial eruptive episode on Oct 14 showed maximum temperatures of ???330??C and TIR data acquired concurrently from a Forward Looking Infrared (FLIR) camera showed maximum temperatures ???675??C, in narrow (???1-m) fractures of molten rock on a new resurgent dome. MASTER and FLIR thermal flux calculations indicated a radiative cooling rate of ???714 J/m2/S over the new dome, corresponding to a radiant power of ???24 MW. MASTER data indicated the new dome was dacitic in composition, and digital elevation data derived from LIDAR acquired concurrently with MASTER showed that the dome growth correlated with the areas of elevated temperatures. Low SO2 concentrations in the plume combined with sub-optimal viewing conditions prohibited quantitative measurement of plume SO2. The results demonstrate that airborne TIR data can provide information on the temperature of both the surface and plume and the composition of new lava during eruptive episodes. Given sufficient resources, the airborne instrumentation could be deployed rapidly to a newly-awakening volcano and provide a means for remote volcano monitoring. Copyright 2005 by the American Geophysical Union.

  2. Monitoring Eruptive Activity at Mount St. Helens with TIR Image Data

    NASA Technical Reports Server (NTRS)

    Vaughan, R. G.; Hook, S. J.; Ramsey, M. S.; Realmuto, V. J.; Schneider, D. J.

    2005-01-01

    Thermal infrared (TIR) data from the MASTER airborne imaging spectrometer were acquired over Mount St. Helens in Sept and Oct, 2004, before and after the onset of recent eruptive activity. Pre-eruption data showed no measurable increase in surface temperatures before the first phreatic eruption on Oct 1. MASTER data acquired during the initial eruptive episode on Oct 14 showed maximum temperatures of similar to approximately 330 C and TIR data acquired concurrently from a Forward Looking Infrared (FLIR) camera showed maximum temperatures similar to approximately 675 C, in narrow (approximately 1-m) fractures of molten rock on a new resurgent dome. MASTER and FLIR thermal flux calculations indicated a radiative cooling rate of approximately 714 J/m(exp 2)/s over the new dome, corresponding to a radiant power of approximately 24 MW. MASTER data indicated the new dome was dacitic in composition, and digital elevation data derived from LIDAR acquired concurrently with MASTER showed that the dome growth correlated with the areas of elevated temperatures. Low SO2 concentrations in the plume combined with sub-optimal viewing conditions prohibited quantitative measurement of plume SO2. The results demonstrate that airborne TIR data can provide information on the temperature of both the surface and plume and the composition of new lava during eruptive episodes. Given sufficient resources, the airborne instrumentation could be deployed rapidly to a newly-awakening volcano and provide a means for remote volcano monitoring.

  3. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2004

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Estes, Steve; Prejean, Stephanie; Sanchez, John J.; Sanches, Rebecca; McNutt, Stephen R.; Paskievitch, John

    2005-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at historically active volcanoes in Alaska since 1988. The primary objectives of the seismic program are the real-time seismic monitoring of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog presents the calculated earthquake hypocenter and phase arrival data, and changes in the seismic monitoring program for the period January 1 through December 31, 2004.These include Mount Wrangell, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Katmai volcanic cluster (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin), Mount Peulik, Aniakchak Crater, Mount Veniaminof, Pavlof Volcano, Mount Dutton, Isanotski Peaks, Shishaldin Volcano, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin Volcano, Okmok Caldera, Great Sitkin Volcano, Kanaga Volcano, Tanaga Volcano, and Mount Gareloi. Over the past year, formal monitoring of Okmok, Tanaga and Gareloi were announced following an extended period of monitoring to determine the background seismicity at each volcanic center. The seismicity at Mount Peulik was still being studied at the end of 2004 and has yet to be added to the list of monitored volcanoes in the AVO weekly update. AVO located 6928 earthquakes in 2004.Monitoring highlights in 2004 include: (1) an earthquake swarm at Westdahl Peak in January; (2) an increase in seismicity at Mount Spurr starting in February continuing through the end of the year into 2005; (4) low-level tremor, and low-frequency events related to intermittent ash and steam emissions at Mount Veniaminof between April and October; (4) low-level tremor at Shishaldin Volcano between April and

  4. Morphological analysis of active Mount Nemrut stratovolcano, eastern Turkey: evidences and possible impact areas of future eruption

    NASA Astrophysics Data System (ADS)

    Aydar, Erkan; Gourgaud, Alain; Ulusoy, Inan; Digonnet, Fabrice; Labazuy, Philippe; Sen, Erdal; Bayhan, Hasan; Kurttas, Turker; Tolluoglu, Arif Umit

    2003-05-01

    Mount Nemrut, an active stratovolcano in eastern Turkey, is a great danger for its vicinity. The volcano possesses a summit caldera which cuts the volcano into two stages, i.e. pre- and post-caldera. Wisps of smoke and hot springs are to be found within the caldera. Although the last recorded volcanic activity is known to have been in 1441, we consider here that the last eruption of Nemrut occurred more recently, probably just before 1597. The present active tectonic regime, historical eruptions, occurrence of mantle-derived magmatic gases and the fumarole and hot spring activities on the caldera floor make Nemrut Volcano a real danger for its vicinity. According to the volcanological past of Nemrut, the styles of expected eruptions are well-focused on two types: (1) occurrence of water within the caldera leads to phreatomagmatic (highly energetic) eruptions, subsequently followed by lava extrusions, and (2) effusions-extrusions (non-explosive or weakly energetic eruptions) on the flanks from fissures. To predict the impact area of future eruptions, a series of morphological analyses based on field observations, Digital Elevation Model and satellite images were realized. Twenty-two valleys (main transport pathways) were classified according to their importance, and the physical parameters related to the valleys were determined. The slope values in each point of the flanks and the Heim parameters H/ L were calculated. In the light of morphological analysis the possible impact areas around the volcano and danger zones were proposed. The possible transport pathways of the products of expected volcanic events are unified in three main directions: Bitlis, Guroymak, Tatvan and Ahlat cities, the about 135 000 inhabitants of which could be threatened by future eruptions of this poorly known and unsurveyed volcano.

  5. Deep structure and origin of active volcanoes in China

    NASA Astrophysics Data System (ADS)

    Zhao, D.

    2010-12-01

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

  6. Road guide to volcanic deposits of Mount St. Helens and vicinity, Washington

    SciTech Connect

    Doukas, M.P.

    1990-01-01

    Mount St. Helens, the most recently active and most intensively studied Cascade volcano, is located in southwestern Washington. The volcano is a superb outdoor laboratory for studying volcanic processes, deposits of observed events, and deposits whose origins are inferred by classic geologic techniques, including analogy to Recent deposits. This road log is a guide to Mount St. Helens Volcano, with emphasis on effects and deposits of the 1980 eruption.

  7. Cascades Volcano Observatory

    USGS Publications Warehouse

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

    2008-01-01

    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/.

  8. Active Volcano Monitoring using a Space-based Hyperspectral Imager

    NASA Astrophysics Data System (ADS)

    Cipar, J. J.; Dunn, R.; Cooley, T.

    2010-12-01

    Active volcanoes occur on every continent, often in close proximity to heavily populated areas. While ground-based studies are essential for scientific research and disaster mitigation, remote sensing from space can provide rapid and continuous monitoring of active and potentially active volcanoes [Ramsey and Flynn, 2004]. In this paper, we report on hyperspectral measurements of Kilauea volcano, Hawaii. Hyperspectral images obtained by the US Air Force TacSat-3/ARTEMIS sensor [Lockwood et al, 2006] are used to obtain estimates of the surface temperatures for the volcano. ARTEMIS measures surface-reflected light in the visible, near-infrared, and short-wave infrared bands (VNIR-SWIR). The SWIR bands are known to be sensitive to thermal radiation [Green, 1996]. For example, images from the NASA Hyperion hyperspectral sensor have shown the extent of wildfires and active volcanoes [Young, 2009]. We employ the methodology described by Dennison et al, (2006) to obtain an estimate of the temperature of the active region of Kilauea. Both day and night-time images were used in the analysis. To improve the estimate, we aggregated neighboring pixels. The active rim of the lava lake is clearly discernable in the temperature image, with a measured temperature exceeding 1100o C. The temperature decreases markedly on the exterior of the summit crater. While a long-wave infrared (LWIR) sensor would be ideal for volcano monitoring, we have shown that the thermal state of an active volcano can be monitored using the SWIR channels of a reflective hyperspectral imager. References: Dennison, Philip E., Kraivut Charoensiri, Dar A. Roberts, Seth H. Peterson, and Robert O. Green (2006). Wildfire temperature and land cover modeling using hyperspectral data, Remote Sens. Environ., vol. 100, pp. 212-222. Green, R. O. (1996). Estimation of biomass fire temperature and areal extent from calibrated AVIRIS spectra, in Summaries of the 6th Annual JPL Airborne Earth Science Workshop, Pasadena, CA

  9. Characteristics, extent and origin of hydrothermal alteration at Mount Rainier Volcano, Cascades Arc, USA: Implications for debris-flow hazards and mineral deposits

    USGS Publications Warehouse

    John, D.A.; Sisson, T.W.; Breit, G.N.; Rye, R.O.; Vallance, J.W.

    2008-01-01

    Hydrothermal alteration at Mount Rainier waxed and waned over the 500,000-year episodic growth of the edifice. Hydrothermal minerals and their stable-isotope compositions in samples collected from outcrop and as clasts from Holocene debris-flow deposits identify three distinct hypogene argillic/advanced argillic hydrothermal environments: magmatic-hydrothermal, steam-heated, and magmatic steam (fumarolic), with minor superimposed supergene alteration. The 3.8??km3 Osceola Mudflow (5600??y BP) and coeval phreatomagmatic F tephra contain the highest temperature and most deeply formed hydrothermal minerals. Relatively deeply formed magmatic-hydrothermal alteration minerals and associations in clasts include quartz (residual silica), quartz-alunite, quartz-topaz, quartz-pyrophyllite, quartz-dickite/kaolinite, and quartz-illite (all with pyrite). Clasts of smectite-pyrite and steam-heated opal-alunite-kaolinite are also common in the Osceola Mudflow. In contrast, the Paradise lahar, formed by collapse of the summit or near-summit of the edifice at about the same time, contains only smectite-pyrite and near-surface steam-heated and fumarolic alteration minerals. Younger debris-flow deposits on the west side of the volcano (Round Pass and distal Electron Mudflows) contain only low-temperature smectite-pyrite assemblages, whereas the proximal Electron Mudflow and a < 100??y BP rock avalanche on Tahoma Glacier also contain magmatic-hydrothermal alteration minerals that are exposed in the avalanche headwall of Sunset Amphitheater, reflecting progressive incision into deeper near-conduit alteration products that formed at higher temperatures. The pre-Osceola Mudflow alteration geometry is inferred to have consisted of a narrow feeder zone of intense magmatic-hydrothermal alteration limited to near the conduit of the volcano, which graded outward to more widely distributed, but weak, smectite-pyrite alteration within 1??km of the edifice axis, developed chiefly in porous

  10. InSAR observations of active volcanoes in Latin America

    NASA Astrophysics Data System (ADS)

    Morales Rivera, A. M.; Chaussard, E.; Amelung, F.

    2012-12-01

    Over the last decade satellite-based interferometric synthetic aperture radar (InSAR) has developed into a well-known technique to gauge the status of active volcanoes. The InSAR technique can detect the ascent of magma to shallow levels of the volcanic plumbing system because new arriving magma pressurizes the system. This is likely associated with the inflation of the volcanic edifice and the surroundings. Although the potential of InSAR to detect magma migration is well known, the principal limitation was that only for few volcanoes frequent observations were acquired. The ALOS-1 satellite of the Japanese Aerospace Exploration Agency (JAXA) acquired a global L-band data set of 15-20 acquisitions during 2006-2011. Here we use ALOS InSAR and Small Baseline (SB) time-series methods for a ground deformation survey of Latin America with emphasis on the northern Andes. We present time-dependent ground deformation data for the volcanoes in Colombia, Ecuador and Peru and interpret the observations in terms of the dynamics of the volcanic systems.

  11. Kizimen Volcano, Kamchatka, Russia: 2010-2012 Eruptive Activity

    NASA Astrophysics Data System (ADS)

    Gordeev, E.; Droznin, V.; Malik, N.; Muravyev, Y.

    2012-12-01

    New eruptive activity at Kizimen Volcano began in October 2010 after 1.5 years of seismic build up. Two vents located at the summit of the volcano had been producing occasional steam-and-gas emissions with traces of ash until early December. Kizimen is located at a junction between Shapensky graben in the Central Kamchatka Depression and a horst of Tumrok Ridge. Kizimen is a 2376 m a.s.l. complex stratovolcano. The only single eruption reported in historic time occurred from December 1928 to January 1929. Little is known about the volcano; explosive activity was preceded by strong local earthquakes, and ashfalls were reported in neighboring settlements. During the period between eruptions the volcano was producing constant fumarolic activity, reported since 1825. During the cause of the current (2010-2012) eruption, the volcano produced several eruptive phases: moderate explosive activity was observed from December 10, 2010 to late February 2011 (ashfalls and descend of pyroclastic flows resulted in a large lahar traveling along the valley of the Poperechny Creek on December 13, 2010); from late February to mid-December the volcano produced an explosive-effusive phase (the lava flow descended eastern flank, while explosive activity has decreased), which resulted in strong explosions on December 14, 2011 accompanied by scores of pyroclastic flows of various thickness to the NE foot on the volcano. Since then, a constant growth of the large lava flow has been accompanied by strong steam-and-gas emissions from the summit crater. The erupted materials are tephra and deposits of pyroclastic and lava flows consisted of high-aluminous andesites and dacites of potassium-sodium series: SiO2 content varied from 61% in December 2010 to 65-68% in January-February 2011, and up to 62% in December 2011. Ashfalls area exceeded 100 km2 (the weight of erupted tephra > 107 tons), while the total area of pyroclastic flows was estimated to be 15.5 km2 (V= 0.16 km3). Until late May 2012

  12. Volcano dome dynamics at Mount St. Helens: Deformation and intermittent subsidence monitored by seismicity and camera imagery pixel offsets

    NASA Astrophysics Data System (ADS)

    Salzer, Jacqueline T.; Thelen, Weston A.; James, Mike R.; Walter, Thomas R.; Moran, Seth; Denlinger, Roger

    2016-11-01

    The surface deformation field measured at volcanic domes provides insights into the effects of magmatic processes, gravity- and gas-driven processes, and the development and distribution of internal dome structures. Here we study short-term dome deformation associated with earthquakes at Mount St. Helens, recorded by a permanent optical camera and seismic monitoring network. We use Digital Image Correlation (DIC) to compute the displacement field between successive images and compare the results to the occurrence and characteristics of seismic events during a 6 week period of dome growth in 2006. The results reveal that dome growth at Mount St. Helens was repeatedly interrupted by short-term meter-scale downward displacements at the dome surface, which were associated in time with low-frequency, large-magnitude seismic events followed by a tremor-like signal. The tremor was only recorded by the seismic stations closest to the dome. We find a correlation between the magnitudes of the camera-derived displacements and the spectral amplitudes of the associated tremor. We use the DIC results from two cameras and a high-resolution topographic model to derive full 3-D displacement maps, which reveals internal dome structures and the effect of the seismic activity on daily surface velocities. We postulate that the tremor is recording the gravity-driven response of the upper dome due to mechanical collapse or depressurization and fault-controlled slumping. Our results highlight the different scales and structural expressions during growth and disintegration of lava domes and the relationships between seismic and deformation signals.

  13. Underwater observations of active lava flows from Kilauea volcano, Hawaii

    USGS Publications Warehouse

    Tribble, G.W.

    1991-01-01

    Underwater observation of active submarine lava flows from Kilauea volcano, Hawaii, in March-June 1989 revealed both pillow lava and highly channelized lava streams flowing down a steep and unconsolidated lava delta. The channelized streams were 0.7-1.5 m across and moved at rates of 1-3 m/s. The estimated flux of a stream was 0.7 m3/s. Jets of hydrothermal water and gas bubbles were associated with the volcanic activity. The rapidly moving channelized lava streams represent a previously undescribed aspect of submarine volcanism. -Author

  14. Study of Seismic Activity at Ceboruco Volcano, Mexico

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    Many societies and their economies endure the disastrous consequences of destructive volcanic eruptions. The Ceboruco stratovolcano (2,280 m.a.s.l.) is located in Nayarit, Mexico, at the west of the Mexican volcanic belt and towards the Sierra de San Pedro southeast, which is a key communication point for coast of Jalisco and Nayarit and the northwest of Mexico. It last eruptive activity was in 1875, and during the following five years it presents superficial activity such as vapor emissions, ash falls and riodacitic composition lava flows along the southeast side. Although surface activity has been restricted to fumaroles near the summit, Ceboruco exhibits regular seismic unrest characterized by both low frequency seismic events and volcano-tectonic earthquakes. From March 2003 until July 2008 a three-component short-period seismograph Marslite station with a Lennartz 3D (1Hz) was deployed in the south flank (CEBN) and within 2 km from the summit to monitoring the seismic activity at the volcano. The LF seismicity recorded was classified using waveform characteristics and digital analysis. We obtained four groups: impulsive arrivals, extended coda, bobbin form, and wave package amplitude modulation earthquakes. The extended coda is the group with more earthquakes and present durations of 50 seconds. Using the moving particle technique, we read the P and S wave arrival times and estimate azimuth arrivals. A P-wave velocity of 3.0 km/s was used to locate the earthquakes, most of the hypocenters are below the volcanic edifice within a circular perimeter of 5 km of radius and its depths are calculated relative to the CEBN elevation as follows. The impulsive arrivals earthquakes present hypocenters between 0 and 1 km while the other groups between 0 and 4 km. Results suggest fluid activity inside the volcanic building that could be related to fumes on the volcano. We conclude that the Ceboruco volcano is active. Therefore, it should be continuously monitored due to the

  15. A Broadly-Based Training Program in Volcano Hazards Monitoring at the Center for the Study of Active Volcanoes

    NASA Astrophysics Data System (ADS)

    Thomas, D. M.; Bevens, D.

    2015-12-01

    The Center for the Study of Active Volcanoes, in cooperation with the USGS Volcano Hazards Program at HVO and CVO, offers a broadly based volcano hazards training program targeted toward scientists and technicians from developing nations. The program has been offered for 25 years and provides a hands-on introduction to a broad suite of volcano monitoring techniques, rather than detailed training with just one. The course content has evolved over the life of the program as the needs of the trainees have changed: initially emphasizing very basic monitoring techniques (e.g. precise leveling, interpretation of seismic drum records, etc.) but, as the level of sophistication of the trainees has increased, training in more advanced technologies has been added. Currently, topics of primary emphasis have included volcano seismology and seismic networks; acquisition and modeling of geodetic data; methods of analysis and monitoring of gas geochemistry; interpretation of volcanic deposits and landforms; training in LAHARZ, GIS mapping of lahar risks; and response to and management of volcanic crises. The course also provides training on public outreach, based on CSAV's Hawaii-specific hazards outreach programs, and volcano preparedness and interactions with the media during volcanic crises. It is an intensive eight week course with instruction and field activities underway 6 days per week; it is now offered in two locations, Hawaii Island, for six weeks, and the Cascades volcanoes of the Pacific Northwest, for two weeks, to enable trainees to experience field conditions in both basaltic and continental volcanic environments. The survival of the program for more than two decades demonstrates that a need for such training exists and there has been interaction and contribution to the program by the research community, however broader engagement with the latter continues to present challenges. Some of the reasons for this will be discussed.

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

    NASA Astrophysics Data System (ADS)

    Evans, John R.; Zucca, John J.

    1988-12-01

    We determine compressional wave velocity and attenuation structures for the upper crust beneath Medicine Lake volcano in northeast California using a high-resolution active source seismic tomography method. 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. This lineament is interpreted to be the result of an old crustal weakness now affecting the emplacement of magma, both on direct ascent from the lower crust and mantle and in migration from the shallow silicic chamber to summit vents. Differences between this high-velocity feature and the equivalent feature at Newbeny volcano, a volcano in central Oregon 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 normal fault mapped at the surface north of the volcano. 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

  17. Mount Rainier: learning to live with volcanic risk

    USGS Publications Warehouse

    Driedger, C.L.; Scott, K.M.

    2002-01-01

    Mount Rainier in Washington state is an active volcano reaching more than 2.7 miles (14,410 feet) above sea level. Its majestic edifice looms over expanding suburbs in the valleys that lead to nearby Puget Sound. USGS research over the last several decades indicates that Mount Rainier has been the source of many volcanic mudflows (lahars) that buried areas now densely populated. Now the USGS is working cooperatively with local communities to help people live more safely with the volcano.

  18. What Are Volcano Hazards?

    MedlinePlus

    ... large landslides have swept down the slopes of Mount Rainier, Washington, during the past 6,000 years. The ... communities downstream from glacier-clad volcanoes, such as Mount Rainier. To help protect lives and property, scientists of ...

  19. Geothermal disruption of ice at Mount Spurr Volcano, 2004 - 2006: An unusual manifestation of volcanic unrest in Alaska

    USGS Publications Warehouse

    Coombs, Michelle L.; Neal, Christina A.; Wessels, Rick L.; McGimsey, Robert G.

    2006-01-01

    Mount Spurr, a 3,374-m-high stratovolcano in the Cook Inlet region of Alaska, showed signs of volcanic unrest beginning in 2004 and lasting through 2006. These signs included increases in heat flow, seismicity, and gas flux, which we interpret as the results of a magmatic intrusion in mid-2004. In response, debris-laden meltwater beneath the glacier in Mount Spurr's geothermally active summit basin accumulated as the overlying snow and ice melted. As heat output increased, the icecap subsided into a growing cavity over a meltwater lake, similar to that observed during subglacial volcanic activity in Iceland. An ice plug collapsed into the lake sometime between June 20 and July 8, 2004, forming an ice cauldron that continued to grow in diameter during 2004 and 2005. A freefall of ice and snow into the lake likely caused a mixture of water and debris to be displaced rapidly upward and outward along preexisting englacial and, possibly, subglacial pathways leading away and downslope from the summit basin. Where these pathways intersected crevasses or other weak points in the sloping icefield, the mixture debouched onto the surface, producing dark, fluid debris flows. In summer 2004, the occurrence of two sets of debris flows separated in time by as long as a week suggests two pulses of summit ice collapse, each producing a surge of water and debris from the lake. A single debris flow was also emplaced on May 2, 2005. This event, which was captured by a Web camera, occurred simultaneously with a lake-level drop of ~15 m. To the east of the ice cauldron, a spillway that fed the debris flows has apparently maintained a relatively constant lake level for months at a time. Aerial photographs show that the spillway is in the direction of a breach in the summit crater. Melting of snow and ice at the summit has continued through 2006, with a total meltwater volume of ~5.4 million m3 as of March 2006.

  20. Aerial monitoring in active mud volcano by UAV technique

    NASA Astrophysics Data System (ADS)

    Pisciotta, Antonino; Capasso, Giorgio; Madonia, Paolo

    2016-04-01

    UAV photogrammetry opens various new applications in the close range domain, combining aerial and terrestrial photogrammetry, but also introduces low-cost alternatives to the classical manned aerial photogrammetry. Between 2014 and 2015 tree aerial surveys have been carried out. Using a quadrotor drone, equipped with a compact camera, it was possible to generate high resolution elevation models and orthoimages of The "Salinelle", an active mud volcanoes area, located in territory of Paternò (South Italy). The main risks are related to the damages produced by paroxysmal events. Mud volcanoes show different cyclic phases of activity, including catastrophic events and periods of relative quiescence characterized by moderate activity. Ejected materials often are a mud slurry of fine solids suspended in liquids which may include water and hydrocarbon fluids, the bulk of released gases are carbon dioxide, with some methane and nitrogen, usually pond-shaped of variable dimension (from centimeters to meters in diameter). The scope of the presented work is the performance evaluation of a UAV system that was built to rapidly and autonomously acquire mobile three-dimensional (3D) mapping data in a volcanic monitoring scenario.

  1. Using the Landsat Thematic Mapper to detect and monitor active volcanoes - An example from Lascar volcano, northern Chile

    NASA Technical Reports Server (NTRS)

    Francis, P. W.; Rothery, D. A.

    1987-01-01

    The Landsat Thematic Mapper (TM) offers a means of detecting and monitoring thermal features of active volcanoes. Using the TM, a prominent thermal anomaly has been discovered on Lascar volcano, northern Chile. Data from two short-wavelength infrared channels of the TM show that material within a 300-m-diameter pit crater was at a temperature of at least 380 C on two dates in 1985. The thermal anomaly closely resembles in size and radiant temperature the anomaly over the active lava lake at Erta'ale in Ethiopia. An eruption took place at Lascar on Sept. 16, 1986. TM data acquired on Oct. 27, 1986, revealed significant changes within the crater area. Lascar is in a much more active state than any other volcano in the central Andes, and for this reason it merits further careful monitoring. Studies show that the TM is capable of confidently identifying thermal anomalies less than 100 m in size, at temperatures of above 150 C, and thus it offers a valuable means of monitoring the conditions of active or potentially active volcanoes, particularly those in remote regions.

  2. Hazard information management during the autumn 2004 reawakening of Mount St. Helens volcano, Washington: Chapter 24 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Driedger, Carolyn L.; Neal, Christina A.; Knappenberger, Tom H.; Needham, Deborah H.; Harper, Robert B.; Steele, William P.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    The 2004 reawakening of Mount St. Helens quickly caught the attention of government agencies as well as the international news media and the public. Immediate concerns focused on a repeat of the catastrophic landslide and blast event of May 18, 1980, which remains a vivid memory for many individuals. Within several days of the onset of accelerating seismicity, media inquiries increased exponentially. Personnel at the U.S. Geological Survey, the Pacific Northwest Seismic Network, and the Gifford Pinchot National Forest soon handled hundreds of press inquiries and held several press briefings per day. About one week into the event, a Joint Information Center was established to help maintain a consistent hazard message and to provide a centralized information source about volcanic activity, hazards, area closures, and media briefings. Scientists, public-affairs specialists, and personnel from emergency-management, health, public-safety, and land-management agencies answered phones, helped in press briefings and interviews, and managed media access to colleagues working on science and safety issues. For scientists, in addition to managing the cycle of daily fieldwork, challenges included (1) balancing accurate interpretations of data under crisis conditions with the need to share information quickly, (2) articulating uncertainties for a variety of volcanic scenarios, (3) minimizing scientific jargon, and (4) frequently updating and effectively distributing talking points. Success of hazard information management during a volcanic crisis depends largely on scientists’ clarity of communication and thorough preplanning among interagency partners. All parties must commit to after-action evaluation and improvement of communication plans, incorporating lessons learned during each event.

  3. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1, 2000 through December 31, 2001

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Estes, Steve; Moran, Seth C.; Paskievitch, John; McNutt, Stephen R.

    2002-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at potentially active volcanoes in Alaska since 1988 (Power and others, 1993; Jolly and others, 1996; Jolly and others, 2001). The primary objectives of this program are the seismic surveillance of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog reflects the status and evolution of the seismic monitoring program, and presents the basic seismic data for the time period January 1, 2000, through December 31, 2001. For an interpretation of these data and previously recorded data, the reader should refer to several recent articles on volcano related seismicity on Alaskan volcanoes in Appendix G.The AVO seismic network was used to monitor twenty-three volcanoes in real time in 2000-2001. These include Mount Wrangell, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Katmai Volcanic Group (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin), Aniakchak Crater, Pavlof Volcano, Mount Dutton, Isanotski Peaks, Shishaldin Volcano, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin Volcano, Great Sitkin Volcano, and Kanaga Volcano (Figure 1). AVO located 1551 and 1428 earthquakes in 2000 and 2001, respectively, on and around these volcanoes.Highlights of the catalog period (Table 1) include: volcanogenic seismic swarms at Shishaldin Volcano between January and February 2000 and between May and June 2000; an eruption at Mount Cleveland between February and May 2001; episodes of possible tremor at Makushin Volcano starting March 2001 and continuing through 2001, and two earthquake swarms at Great Sitkin Volcano in 2001.This catalog includes: (1) earthquake origin times

  4. International Global Atmospheric Chemistry Programme global emissions inventory activity: Sulfur emissions from volcanoes, current status

    SciTech Connect

    Benkovitz, C.M.

    1995-07-01

    Sulfur emissions from volcanoes are located in areas of volcanic activity, are extremely variable in time, and can be released anywhere from ground level to the stratosphere. Previous estimates of global sulfur emissions from all sources by various authors have included estimates for emissions from volcanic activity. In general, these global estimates of sulfur emissions from volcanoes are given as global totals for an ``average`` year. A project has been initiated at Brookhaven National Laboratory to compile inventories of sulfur emissions from volcanoes. In order to complement the GEIA inventories of anthropogenic sulfur emissions, which represent conditions circa specific years, sulfur emissions from volcanoes are being estimated for the years 1985 and 1990.

  5. Frictional properties of the Mount St. Helens gouge: Chapter 20 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Moore, Peter L.; Iverson, Neal R.; Iverson, Richard M.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    Rate-weakening friction is a requirement for stick-slip behavior that is satisfied by the Mount St. Helens gouge. Indeed, regular stick-slip oscillations were observed in two experiments performed at the highest normal stress and lowest rates of shear. The conditions under which this stick-slip motion occurred indicate that the gouge also satisfies a second criterion for stick-slip behavior of materials exhibiting rateand-state dependent friction-gouge stiffness exceeds that of the ascending magma that drives upward motion of the plug. The presence of highly compliant magma as a driving element may be crucial for generating stick-slip instabilities at the shallow earthquake focal depths observed during the eruption.

  6. The 2005 catastrophic acid crater lake drainage, lahar, and acidic aerosol formation at Mount Chiginagak volcano, Alaska, USA: Field observations and preliminary water and vegetation chemistry results

    NASA Astrophysics Data System (ADS)

    Schaefer, Janet R.; Scott, William E.; Evans, William C.; Jorgenson, Janet; McGimsey, Robert G.; Wang, Bronwen

    2008-07-01

    A mass of snow and ice 400-m-wide and 105-m-thick began melting in the summit crater of Mount Chiginagak volcano sometime between November 2004 and early May 2005, presumably owing to increased heat flux from the hydrothermal system, or possibly from magma intrusion and degassing. In early May 2005, an estimated 3.8 × 106 m3 of sulfurous, clay-rich debris and acidic water, with an accompanying acidic aerosol component, exited the crater through a tunnel at the base of a glacier that breaches the south crater rim. Over 27 km downstream, the acidic waters of the flood inundated an important salmon spawning drainage, acidifying Mother Goose Lake from surface to depth (approximately 0.5 km3 in volume at a pH of 2.9 to 3.1), killing all aquatic life, and preventing the annual salmon run. Over 2 months later, crater lake water sampled 8 km downstream of the outlet after considerable dilution from glacial meltwater was a weak sulfuric acid solution (pH = 3.2, SO4 = 504 mg/L, Cl = 53.6 mg/L, and F = 7.92 mg/L). The acid flood waters caused severe vegetation damage, including plant death and leaf kill along the flood path. The crater lake drainage was accompanied by an ambioructic flow of acidic aerosols that followed the flood path, contributing to defoliation and necrotic leaf damage to vegetation in a 29 km2 area along and above affected streams, in areas to heights of over 150 m above stream level. Moss species killed in the event contained high levels of sulfur, indicating extremely elevated atmospheric sulfur content. The most abundant airborne phytotoxic constituent was likely sulfuric acid aerosols that were generated during the catastrophic partial crater lake drainage event. Two mechanisms of acidic aerosol formation are proposed: (1) generation of aerosol mist through turbulent flow of acidic water and (2) catastrophic gas exsolution. This previously undocumented phenomenon of simultaneous vegetation-damaging acidic aerosols accompanying drainage of an acidic

  7. The 2005 catastrophic acid crater lake drainage, lahar, and acidic aerosol formation at Mount Chiginagak volcano, Alaska, USA: Field observations and preliminary water and vegetation chemistry results

    USGS Publications Warehouse

    Schaefer, J.R.; Scott, W.E.; Evans, William C.; Jorgenson, J.; McGimsey, R.G.; Wang, B.

    2008-01-01

    A mass of snow and ice 400-m-wide and 105-m-thick began melting in the summit crater of Mount Chiginagak volcano sometime between November 2004 and early May 2005, presumably owing to increased heat flux from the hydrothermal system, or possibly from magma intrusion and degassing. In early May 2005, an estimated 3.8??106 m3 of sulfurous, clay-rich debris and acidic water, with an accompanying acidic aerosol component, exited the crater through a tunnel at the base of a glacier that breaches the south crater rim. Over 27 km downstream, the acidic waters of the flood inundated an important salmon spawning drainage, acidifying Mother Goose Lake from surface to depth (approximately 0.5 km3 in volume at a pH of 2.9 to 3.1), killing all aquatic life, and preventing the annual salmon run. Over 2 months later, crater lake water sampled 8 km downstream of the outlet after considerable dilution from glacial meltwater was a weak sulfuric acid solution (pH = 3.2, SO4 = 504 mg/L, Cl = 53.6 mg/L, and F = 7.92 mg/L). The acid flood waters caused severe vegetation damage, including plant death and leaf kill along the flood path. The crater lake drainage was accompanied by an ambioructic flow of acidic aerosols that followed the flood path, contributing to defoliation and necrotic leaf damage to vegetation in a 29 km2 area along and above affected streams, in areas to heights of over 150 m above stream level. Moss species killed in the event contained high levels of sulfur, indicating extremely elevated atmospheric sulfurcontent. The most abundant airborne phytotoxic constituent was likely sulfuric acid aerosols that were generated during the catastrophic partial crater lake drainage event. Two mechanisms of acidic aerosol formation are proposed: (1) generation of aerosol mist through turbulent flow of acidic water and (2) catastrophic gas exsolution. This previously undocumented phenomenon of simultaneous vegetationdamaging acidic aerosols accompanying drainage of an acidic crater

  8. Quantitative measurements of active Ionian volcanoes in Galileo NIMS data

    NASA Astrophysics Data System (ADS)

    Saballett, Sebastian; Rathbun, Julie A.; Lopes, Rosaly M. C.; Spencer, John R.

    2016-10-01

    Io is the most volcanically active body in our solar system. The spatial distribution of volcanoes a planetary body's surface gives clues into its basic inner workings (i.e., plate tectonics on earth). Tidal heating is the major contributor to active surface geology in the outer solar system, and yet its mechanism is not completely understood. Io's volcanoes are the clearest signature of tidal heating and measurements of the total heat output and how it varies in space and time are useful constraints on tidal heating. Hamilton et al. (2013) showed through a nearest neighbor analysis that Io's hotspots are globally random, but regionally uniform near the equator. Lopes-Gautier et al. (1999) compared the locations of hotspots detected by NIMS to the spatial variation of heat flow predicted by two end-member tidal heating models. They found that the distribution of hotspots is more consistent with tidal heating occurring in asthenosphere rather than the mantle. Hamilton et al. (2013) demonstrate that clustering of hotspots also supports a dominant role for asthenosphere heating. These studies were unable to account for the relative brightness of the hotspots. Furthermore, studies of the temporal variability of Ionian volcanoes have yielded substantial insight into their nature. The Galileo Near Infrared Mapping Spectrometer (NIMS) gave us a large dataset from which to observe active volcanic activity. NIMS made well over 100 observations of Io over an approximately 10-year time frame. With wavelengths spanning from 0.7 to 5.2 microns, it is ideally suited to measure blackbody radiation from surfaces with temperatures over 300 K. Here, we report on our effort to determine the activity level of each hotspot observed in the NIMS data. We decide to use 3.5 micron brightness as a proxy for activity level because it will be easy to compare to, and incorporate, ground-based observations. We fit a 1-temperature blackbody to spectra in each grating position and averaged the

  9. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2003

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Moran, Seth C.; Sanchez, John J.; McNutt, Stephen R.; Estes, Steve; Paskievitch, John

    2004-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at historically active volcanoes in Alaska since 1988. The primary objectives of this program are the near real time seismic monitoring of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog presents the calculated earthquake hypocenter and phase arrival data, and changes in the seismic monitoring program for the period January 1 through December 31, 2003.The AVO seismograph network was used to monitor the seismic activity at twenty-seven volcanoes within Alaska in 2003. These include Mount Wrangell, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Katmai volcanic cluster (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin), Aniakchak Crater, Mount Veniaminof, Pavlof Volcano, Mount Dutton, Isanotski Peaks, Shishaldin Volcano, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin Volcano, Okmok Caldera, Great Sitkin Volcano, Kanaga Volcano, Tanaga Volcano, and Mount Gareloi. Monitoring highlights in 2003 include: continuing elevated seismicity at Mount Veniaminof in January-April (volcanic unrest began in August 2002), volcanogenic seismic swarms at Shishaldin Volcano throughout the year, and low-level tremor at Okmok Caldera throughout the year. Instrumentation and data acquisition highlights in 2003 were the installation of subnetworks on Tanaga and Gareloi Islands, the installation of broadband installations on Akutan Volcano and Okmok Caldera, and the establishment of telemetry for the Okmok Caldera subnetwork. AVO located 3911 earthquakes in 2003.This catalog includes: (1) a description of instruments deployed in the field and their locations; (2) a

  10. Deep long-period earthquakes beneath Washington and Oregon volcanoes

    USGS Publications Warehouse

    Nichols, M.L.; Malone, S.D.; Moran, S.C.; Thelen, W.A.; Vidale, J.E.

    2011-01-01

    Deep long-period (DLP) earthquakes are an enigmatic type of seismicity occurring near or beneath volcanoes. They are commonly associated with the presence of magma, and found in some cases to correlate with eruptive activity. To more thoroughly understand and characterize DLP occurrence near volcanoes in Washington and Oregon, we systematically searched the Pacific Northwest Seismic Network (PNSN) triggered earthquake catalog for DLPs occurring between 1980 (when PNSN began collecting digital data) and October 2009. Through our analysis we identified 60 DLPs beneath six Cascade volcanic centers. No DLPs were associated with volcanic activity, including the 1980-1986 and 2004-2008 eruptions at Mount St. Helens. More than half of the events occurred near Mount Baker, where the background flux of magmatic gases is greatest among Washington and Oregon volcanoes. The six volcanoes with DLPs (counts in parentheses) are Mount Baker (31), Glacier Peak (9), Mount Rainier (9), Mount St. Helens (9), Three Sisters (1), and Crater Lake (1). No DLPs were identified beneath Mount Adams, Mount Hood, Mount Jefferson, or Newberry Volcano, although (except at Hood) that may be due in part to poorer network coverage. In cases where the DLPs do not occur directly beneath the volcanic edifice, the locations coincide with large structural faults that extend into the deep crust. Our observations suggest the occurrence of DLPs in these areas could represent fluid and/or magma transport along pre-existing tectonic structures in the middle crust. ?? 2010 Elsevier B.V.

  11. Deep long-period earthquakes beneath Washington and Oregon volcanoes

    NASA Astrophysics Data System (ADS)

    Nichols, M. L.; Malone, S. D.; Moran, S. C.; Thelen, W. A.; Vidale, J. E.

    2011-03-01

    Deep long-period (DLP) earthquakes are an enigmatic type of seismicity occurring near or beneath volcanoes. They are commonly associated with the presence of magma, and found in some cases to correlate with eruptive activity. To more thoroughly understand and characterize DLP occurrence near volcanoes in Washington and Oregon, we systematically searched the Pacific Northwest Seismic Network (PNSN) triggered earthquake catalog for DLPs occurring between 1980 (when PNSN began collecting digital data) and October 2009. Through our analysis we identified 60 DLPs beneath six Cascade volcanic centers. No DLPs were associated with volcanic activity, including the 1980-1986 and 2004-2008 eruptions at Mount St. Helens. More than half of the events occurred near Mount Baker, where the background flux of magmatic gases is greatest among Washington and Oregon volcanoes. The six volcanoes with DLPs (counts in parentheses) are Mount Baker (31), Glacier Peak (9), Mount Rainier (9), Mount St. Helens (9), Three Sisters (1), and Crater Lake (1). No DLPs were identified beneath Mount Adams, Mount Hood, Mount Jefferson, or Newberry Volcano, although (except at Hood) that may be due in part to poorer network coverage. In cases where the DLPs do not occur directly beneath the volcanic edifice, the locations coincide with large structural faults that extend into the deep crust. Our observations suggest the occurrence of DLPs in these areas could represent fluid and/or magma transport along pre-existing tectonic structures in the middle crust.

  12. Catalogue of satellite photography of the active volcanoes of the world

    NASA Technical Reports Server (NTRS)

    Heiken, G.

    1976-01-01

    A catalogue is presented of active volcanoes as viewed from Earth-orbiting satellites. The listing was prepared of photographs, which have been screened for quality, selected from the earth resources technology satellite (ERTS) and Skylab, Apollo and Gemini spacecraft. There is photography of nearly every active volcano in the world; the photographs are particularly useful for regional studies of volcanic fields.

  13. Chlorine degassing during the lava dome-building eruption of Mount St. Helens, 2004-2005: Chapter 27 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Edmonds, Marie; McGee, Kenneth A.; Doukas, Michael P.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    O is magmatic, and (or) (2) some Cl present as alkali chloride (NaCl and KCl) in the gas phase. The mean molar Cl/S is similar to gases measured at other silicic subductionzone volcanoes during effusive activity; this may be due to the influence of Cl in the vapor on S solubility in the melt, which produces a solubility maximum for S at vapor Cl/S ~1.

  14. Volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory 1993

    USGS Publications Warehouse

    Neal, Christina A.; McGimsey, Robert G.; Doukas, Michael P.

    1996-01-01

    During 1993, the Alaska Volcano Observatory (AVO) responded to episodes of eruptive activity or false alarms at nine volcanic centers in the state of Alaska. Additionally, as part of a formal role in KVERT (the Kamchatkan Volcano Eruption Response Team), AVO staff also responded to eruptions on the Kamchatka Peninsula, details of which are summarized in Miller and Kurianov (1993). In 1993, AVO maintained seismic instrumentation networks on four volcanoes of the Cook Inlet region--Spurr, Redoubt, Iliamna, and Augustine--and two stations at Dutton Volcano near King Cove on the Alaska Peninsula. Other routine elements of AVO's volcano monitoring program in Alaska include periodic airborne measurement of volcanic SO2 and CO2 at Cook Inlet volcanoes (Doukas, 1995) and maintenance of a lightning detection system in Cook Inlet (Paskievitch and others, 1995).

  15. Characteristics, extent and origin of hydrothermal alteration at Mount Rainier Volcano, Cascades Arc, USA: Implications for debris-flow hazards and mineral deposits

    NASA Astrophysics Data System (ADS)

    John, David A.; Sisson, Thomas W.; Breit, George N.; Rye, Robert O.; Vallance, James W.

    2008-08-01

    Hydrothermal alteration at Mount Rainier waxed and waned over the 500,000-year episodic growth of the edifice. Hydrothermal minerals and their stable-isotope compositions in samples collected from outcrop and as clasts from Holocene debris-flow deposits identify three distinct hypogene argillic/advanced argillic hydrothermal environments: magmatic-hydrothermal, steam-heated, and magmatic steam (fumarolic), with minor superimposed supergene alteration. The 3.8 km 3 Osceola Mudflow (5600 y BP) and coeval phreatomagmatic F tephra contain the highest temperature and most deeply formed hydrothermal minerals. Relatively deeply formed magmatic-hydrothermal alteration minerals and associations in clasts include quartz (residual silica), quartz-alunite, quartz-topaz, quartz-pyrophyllite, quartz-dickite/kaolinite, and quartz-illite (all with pyrite). Clasts of smectite-pyrite and steam-heated opal-alunite-kaolinite are also common in the Osceola Mudflow. In contrast, the Paradise lahar, formed by collapse of the summit or near-summit of the edifice at about the same time, contains only smectite-pyrite and near-surface steam-heated and fumarolic alteration minerals. Younger debris-flow deposits on the west side of the volcano (Round Pass and distal Electron Mudflows) contain only low-temperature smectite-pyrite assemblages, whereas the proximal Electron Mudflow and a < 100 y BP rock avalanche on Tahoma Glacier also contain magmatic-hydrothermal alteration minerals that are exposed in the avalanche headwall of Sunset Amphitheater, reflecting progressive incision into deeper near-conduit alteration products that formed at higher temperatures. The pre-Osceola Mudflow alteration geometry is inferred to have consisted of a narrow feeder zone of intense magmatic-hydrothermal alteration limited to near the conduit of the volcano, which graded outward to more widely distributed, but weak, smectite-pyrite alteration within 1 km of the edifice axis, developed chiefly in porous breccias

  16. Volcano Hazards Assessment for Medicine Lake Volcano, Northern California

    USGS Publications Warehouse

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

    2007-01-01

    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.

  17. Selenium speciation in acidic environmental samples: application to acid rain-soil interaction at Mount Etna volcano.

    PubMed

    Floor, Geerke H; Iglesías, Mònica; Román-Ross, Gabriela; Corvini, Philippe F X; Lenz, Markus

    2011-09-01

    Speciation plays a crucial role in elemental mobility. However, trace level selenium (Se) speciation analyses in aqueous samples from acidic environments are hampered due to adsorption of the analytes (i.e. selenate, selenite) on precipitates. Such solid phases can form during pH adaptation up till now necessary for chromatographic separation. Thermodynamic calculations in this study predicted that a pH<4 is needed to prevent precipitation of Al and Fe phases. Therefore, a speciation method with a low pH eluent that matches the natural sample pH of acid rain-soil interaction samples from Etna volcano was developed. With a mobile phase containing 20mM ammonium citrate at pH 3, selenate and selenite could be separated in different acidic media (spiked water, rain, soil leachates) in <10 min with a LOQ of 0.2 μg L(-1) using (78)Se for detection. Applying this speciation analysis to study acid rain-soil interaction using synthetic rain based on H(2)SO(4) and soil samples collected at the flanks of Etna volcano demonstrated the dominance of selenate over selenite in leachates from samples collected close to the volcanic craters. This suggests that competitive behavior with sulfate present in acid rain might be a key factor in Se mobilization. The developed speciation method can significantly contribute to understand Se cycling in acidic, Al/Fe rich environments.

  18. Thermal surveillance of volcanoes

    NASA Technical Reports Server (NTRS)

    Friedman, J. D. (Principal Investigator)

    1972-01-01

    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.

  19. Ground-based observations of time variability in multiple active volcanoes on Io

    NASA Astrophysics Data System (ADS)

    Rathbun, Julie A.; Spencer, John R.

    2010-10-01

    Since before the beginning of the Galileo spacecraft's Jupiter orbital tour, we have observed Io from the ground using NASA's Infrared Telescope Facility (IRTF). We obtained images of Io in reflected sunlight and in-eclipse at 2.3, 3.5, and 4.8 μm. In addition, we have measured the 3.5 μm brightness of an eclipsed Io as it is occulted by Jupiter. These lightcurves enable us to measure the brightness and one-dimensional location of active volcanoes on the surface. During the Galileo era, two volcanoes were observed to be regularly active: Loki and either Kanehekili and/or Janus. At least 12 other active volcanoes were observed for shorter periods of time, including one distinguishable in images that include reflected sunlight. These data can be used to compare volcano types and test volcano eruption models, such as the lava lake model for Loki.

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    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.

  1. The recent seismo-volcanic activity at Deception Island volcano

    NASA Astrophysics Data System (ADS)

    Ibáñez, Jesús M.; Almendros, Javier; Carmona, Enrique; Martínez-Arévalo, Carmen; Abril, Miguel

    2003-06-01

    This paper reviews the recent seismic studies carried out at Deception Island, South Shetland Islands, Antarctica, which was monitored by the Argentinean and Spanish Antarctic Programs since 1986. Several types of seismic network have been deployed temporarily during each Antarctic summer. These networks have consisted of a variety of instruments, including radio-telemetered stations, autonomous digital seismic stations, broadband seismometers, and seismic arrays. We have identified two main types of seismic signals generated by the volcano, namely pure seismo-volcanic signals, such as volcanic tremor and long-period (LP) events, and volcano-tectonic (VT) earthquakes. Their temporal distributions are far from homogeneous. Volcanic tremors and LP events usually occur in seismic swarms lasting from a few hours to some days. The number of LP events in these swarms is highly variable, from a background level of less than 30/day to a peak activity of about 100 events/h. The occurrence of VT earthquakes is even more irregular. Most VT earthquakes at Deception Island have been recorded during two intense seismic crises, in 1992 and 1999, respectively. Some of these VT earthquakes were large enough to be felt by researchers working on the island. Analyses of both types of seismic events have allowed us to derive source locations, establish seismic source models, analyze seismic attenuation, calculate the energy and stress drop of the seismic sources, and relate the occurrence of seismicity to the volcanic activity. Pure seismo-volcanic signals are modelled as the consequence of hydrothermal interactions between a shallow aquifer and deeper hot materials, resulting in the resonance of fluid-filled fractures. VT earthquakes constitute the brittle response to changes in the distribution of stress in the volcanic edifice. The two VT seismic series are probably related to uplift episodes due to deep injections of magma that did not reach the surface. This evidence, however

  2. Evolution of Deformation Studies on Active Hawaiian Volcanoes

    USGS Publications Warehouse

    Decker, Robert; Okamura, Arnold; Miklius, Asta; Poland, Michael

    2008-01-01

    Everything responds to pressure, even rocks. Deformation studies involve measuring and interpreting the changes in elevations and horizontal positions of the land surface or sea floor. These studies are variously referred to as geodetic changes or ground-surface deformations and are sometimes indexed under the general heading of geodesy. Deformation studies have been particularly useful on active volcanoes and in active tectonic areas. A great amount of time and energy has been spent on measuring geodetic changes on Kilauea and Mauna Loa Volcanoes in Hawai`i. These changes include the build-up of the surface by the piling up and ponding of lava flows, the changes in the surface caused by erosion, and the uplift, subsidence, and horizontal displacements of the surface caused by internal processes acting beneath the surface. It is these latter changes that are the principal concern of this review. A complete and objective review of deformation studies on active Hawaiian volcanoes would take many volumes. Instead, we attempt to follow the evolution of the most significant observations and interpretations in a roughly chronological way. It is correct to say that this is a subjective review. We have spent years measuring and recording deformation changes on these great volcanoes and more years trying to understand what makes these changes occur. We attempt to make this a balanced as well as a subjective review; the references are also selective rather than exhaustive. Geodetic changes caused by internal geologic processes vary in magnitude from the nearly infinitesimal - one micron or less, to the very large - hundreds of meters. Their apparent causes also are varied and include changes in material properties and composition, atmospheric pressure, tidal stress, thermal stress, subsurface-fluid pressure (including magma pressure, magma intrusion, or magma removal), gravity, and tectonic stress. Deformation is measured in units of strain or displacement. For example, tilt

  3. Recent Activity of Glaciers of Mount Rainier, Washington

    USGS Publications Warehouse

    Sigafoos, Robert S.; Hendricks, E.L.

    1972-01-01

    Knowing the ages of trees growing on recent moraines at Mount Rainier, Wash., permits the moraines to be dated. Moraines which are ridges of boulders, gravel, sand, and dust deposited at the margins of a glacier, mark former limits of a receding glacier. Knowing past glacial activity aids our understanding of past climatic variations. The report documents the ages of moraines deposited by eight glaciers. Aerial photographs and planimetric maps show areas where detailed field studies were made below seven glaciers. Moraines, past ice positions, and sample areas are plotted on the photographs and maps, along with trails, roads, streams, and landforms, to permit critical areas to be identified in the future. Ground photographs are included so that sample sites and easily accessible moraines can be found along trails. Tables present data about trees sampled in areas near the glaciers of Mount Rainier, Wash. The data in the tables show there are modern moraines of different age around the mountain; some valleys contain only one modern moraiine; others contain as many as nine. The evidence indicates a sequence of modern glacial advances terminating at about the following A.D. dates: 1525, 1550, 1625-60, 1715, 1730-65, 1820-60, 1875, and 1910. Nisqually River valley near Nisqually Glacier contains one moraine formed before A.D. 1842; Tahoma Creek valley near South Tahoma Glacier contains three moraines formed before A.D. 1528; 1843, and 1864; South Puyallup River valley near Tahoma Glacier, six moraines A.D. 1544, 1761, 1841, 1851, 1863, 1898; Puyallup Glacier, one moraine, A.D. 1846; Carbon Glacier, four moraines, 1519, 1763, 1847, 1876; Winthrop Glacier, four moraines, 1655, 1716, 1760, amid 1822; Emmons Glacier, nine moraines, 1596, 1613, 1661, 1738, 1825, 1850, 1865, 1870, 1901; and Ohanapecosh Glacier, three moraines, 1741, 1846, and 1878. Abandoned melt-water and flood channels were identified within moraine complexes below three glaciers, and their time of

  4. History and hazards of Mount Rainier, Washington

    USGS Publications Warehouse

    Sisson, Thomas W.

    1995-01-01

    Mount Rainier is an active volcano that first erupted about half a million years ago. Because of Rainier's great height (14,410 feet above sea level) and northerly location, glaciers have cut deeply into its lavas, making it appear deceptively older than it actually is. Mount Rainier is known to have erupted as recently as in the 1840s, and large eruptions took place as recently as about 1,000 and 2,300 years ago.

  5. Volcanic hazards at Mount Shasta, California

    USGS Publications Warehouse

    Crandell, Dwight R.; Nichols, Donald R.

    1989-01-01

    The eruptions of Mount St. Helens, Washington, in 1980 served as a reminder that long-dormant volcanoes can come to life again. Those eruptions, and their effects on people and property, also showed the value of having information about volcanic hazards well in advance of possible volcanic activity. This pamphlet about Mount Shasta provides such information for the public, even though the next eruption may still be far in the future.

  6. Recent Seismic and Geodetic Activity at Multiple Volcanoes in the Ecuadorean Andes

    NASA Astrophysics Data System (ADS)

    Hernandez, S.; Ruiz, M. C.; McCausland, W. A.; Prejean, S. G.; Mothes, P. A.; Bell, A. F.; Hidalgo, S.; Barrington, C.; Yepez, M.; Aguaiza, S.; Plain, M.

    2015-12-01

    The state of volcanic activity often fluctuates between periods of repose and unrest. The transition time between a period of repose and unrest, or vice versa for an open system, can occur within a matter of hours or days. Because of this short time scale, real-time seismic and geodetic (e.g. tiltmeter, GPS) monitoring networks are crucial for characterizing the state of activity of a volcano. In the Ecuadorean Andes, 5 volcanoes demonstrate long-term (Tungurahua, Reventador, and Guagua Pichincha) or recently reactivated (Cotopaxi, Chiles-Cerro Negro) seismic and geodetic activity. The Instituto Geofisico regularly characterizes volcano seismicity into long period, very long period, volcano-tectonic, and tremor events. Significant recent changes at these volcanoes include: rigorous reactivation of glacier-capped Cotopaxi, drumbeat seismicity absent a dome extrusion at Tungurahua, and regularly reoccurring (~7 day recurrence interval), shallow seismic swarms at Guagua Pichincha. These volcanoes locate along both the Western and Eastern Cordillera of the Ecuadorean Andes and, where data are available, manifest important variations in chemical composition, daily gas flux, and surficial deformation. We summarize the long-term geophysical parameters measured at each volcano and place recent changes in each parameter in a larger magmatic and hydrothermal context. All of the studied volcanoes present significant societal hazards to local and regional communities.

  7. The critical role of volcano monitoring in risk reduction

    NASA Astrophysics Data System (ADS)

    Tilling, R. I.

    2008-01-01

    Data from volcano-monitoring studies constitute the only scientifically valid basis for short-term forecasts of a future eruption, or of possible changes during an ongoing eruption. Thus, in any effective hazards-mitigation program, a basic strategy in reducing volcano risk is the initiation or augmentation of volcano monitoring at historically active volcanoes and also at geologically young, but presently dormant, volcanoes with potential for reactivation. Beginning with the 1980s, substantial progress in volcano-monitoring techniques and networks - ground-based as well space-based - has been achieved. Although some geochemical monitoring techniques (e.g., remote measurement of volcanic gas emissions) are being increasingly applied and show considerable promise, seismic and geodetic methods to date remain the techniques of choice and are the most widely used. Availability of comprehensive volcano-monitoring data was a decisive factor in the successful scientific and governmental responses to the reawakening of Mount St. elens (Washington, USA) in 1980 and, more recently, to the powerful explosive eruptions at Mount Pinatubo (Luzon, Philippines) in 1991. However, even with the ever-improving state-of-the-art in volcano monitoring and predictive capability, the Mount St. Helens and Pinatubo case histories unfortunately still represent the exceptions, rather than the rule, in successfully forecasting the most likely outcome of volcano unrest.

  8. The critical role of volcano monitoring in risk reduction

    USGS Publications Warehouse

    Tilling, R.I.

    2008-01-01

    Data from volcano-monitoring studies constitute the only scientifically valid basis for short-term forecasts of a future eruption, or of possible changes during an ongoing eruption. Thus, in any effective hazards-mitigation program, a basic strategy in reducing volcano risk is the initiation or augmentation of volcano monitoring at historically active volcanoes and also at geologically young, but presently dormant, volcanoes with potential for reactivation. Beginning with the 1980s, substantial progress in volcano-monitoring techniques and networks - ground-based as well space-based - has been achieved. Although some geochemical monitoring techniques (e.g., remote measurement of volcanic gas emissions) are being increasingly applied and show considerable promise, seismic and geodetic methods to date remain the techniques of choice and are the most widely used. Availability of comprehensive volcano-monitoring data was a decisive factor in the successful scientific and governmental responses to the reawakening of Mount St. Helens (Washington, USA) in 1980 and, more recently, to the powerful explosive eruptions at Mount Pinatubo (Luzon, Philippines) in 1991. However, even with the ever-improving state-ofthe-art in volcano monitoring and predictive capability, the Mount St. Helens and Pinatubo case histories unfortunately still represent the exceptions, rather than the rule, in successfully forecasting the most likely outcome of volcano unrest.

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

    NASA Astrophysics Data System (ADS)

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

    1999-05-01

    Sangay (5230 m), the southernmost active volcano of the Andean Northern Volcanic Zone (NVZ), sits ˜130 km above a >32-Ma-old slab, close to a major tear that separates two distinct subducting oceanic crusts. Southwards, Quaternary volcanism is absent along a 1600-km-long segment of the Andes. Three successive edifices of decreasing volume have formed the Sangay volcanic complex during the last 500 ka. Two former cones (Sangay I and II) have been largely destroyed by sector collapses that resulted in large debris avalanches that flowed out upon the Amazon plain. Sangay III, being constructed within the last avalanche amphitheater, has been active at least since 14 ka BP. Only the largest eruptions with unusually high Plinian columns are likely to represent a major hazard for the inhabited areas located 30 to 100 km west of the volcano. However, given the volcano's relief and unbuttressed eastern side, a future collapse must be considered, that would seriously affect an area of present-day colonization in the Amazon plain, ˜30 km east of the summit. Andesites greatly predominate at Sangay, there being few dacites and basalts. In order to explain the unusual characteristics of the Sangay suite—highest content of incompatible elements (except Y and HREE) of any NVZ suite, low Y and HREE values in the andesites and dacites, and high Nb/La of the only basalt found—a preliminary five-step model is proposed: (1) an enriched mantle (in comparison with an MORB source), or maybe a variably enriched mantle, at the site of the Sangay, prior to Quaternary volcanism; (2) metasomatism of this mantle by important volumes of slab-derived fluids enriched in soluble incompatible elements, due to the subduction of major oceanic fracture zones; (3) partial melting of this metasomatized mantle and generation of primitive basaltic melts with Nb/La values typical of the NVZ, which are parental to the entire Sangay suite but apparently never reach the surface and subordinate

  10. Rebuilding Mount St. Helens

    USGS Publications Warehouse

    Schilling, Steve P.; Ramsey, David W.; Messerich, James A.; Thompson, Ren A.

    2006-01-01

    On May 18, 1980, Mount St. Helens, Washington exploded in a spectacular and devastating eruption that shocked the world. The eruption, one of the most powerful in the history of the United States, removed 2.7 cubic kilometers of rock from the volcano's edifice, the bulk of which had been constructed by nearly 4,000 years of lava-dome-building eruptions. In seconds, the mountain's summit elevation was lowered from 2,950 meters to 2,549 meters, leaving a north-facing, horseshoe-shaped crater over 2 kilometers wide. Following the 1980 eruption, Mount St. Helens remained active. A large lava dome began episodically extruding in the center of the volcano's empty crater. This dome-building eruption lasted until 1986 and added about 80 million cubic meters of rock to the volcano. During the two decades following the May 18, 1980 eruption, Crater Glacier formed tongues of ice around the east and west sides of the lava dome in the deeply shaded niche between the lava dome and the south crater wall. Long the most active volcano in the Cascade Range with a complex 300,000-year history, Mount St. Helens erupted again in the fall of 2004 as a new period of dome building began within the 1980 crater. Between October 2004 and February 2006, about 80 million cubic meters of dacite lava erupted immediately south of the 1980-86 lava dome. The erupting lava separated the glacier into two parts, first squeezing the east arm of the glacier against the east crater wall and then causing equally spectacular crevassing and broad uplift of the glacier's west arm. Vertical aerial photographs document dome growth and glacier deformation. These photographs enabled photogrammetric construction of a series of high-resolution digital elevation models (DEMs) showing changes from October 4, 2004 to February 9, 2006. From the DEMs, Geographic Information Systems (GIS) applications were used to estimate extruded volumes and growth rates of the new lava dome. The DEMs were also used to quantify dome

  11. Seismic-monitoring changes and the remote deployment of seismic stations (seismic spider) at Mount St. Helens, 2004-2005: Chapter 7 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    McChesney, Patrick J.; Couchman, Marvin R.; Moran, Seth C.; Lockhart, Andrew B.; Swinford, Kelly J.; LaHusen, Richard G.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    The instruments in place at the start of volcanic unrest at Mount St. Helens in 2004 were inadequate to record the large earthquakes and monitor the explosions that occurred as the eruption developed. To remedy this, new instruments were deployed and the short-period seismic network was modified. A new method of establishing near-field seismic monitoring was developed, using remote deployment by helicopter. The remotely deployed seismic sensor was a piezoelectric accelerometer mounted on a surface-coupled platform. Remote deployment enabled placement of stations within 250 m of the active vent.

  12. The use of multispectral thermal infrared image data to estimate the sulfur dioxide flux from volcanoes: A case study from Mount Etna, Sicily, July 29, 1986

    SciTech Connect

    Realmuto, V.J.; Abrams, M.J.; Buongiorno, M.F.; Pieri, D.C. )

    1994-01-10

    The authors have found that image data acquired with NASA's airborne Thermal Infrared Multispectral Scanner (TIMS) can be used to make estimates of the SO[sub 2] content of volcanic plumes. TIMS image data are most applicable to the study of partially transparent SO[sub 2] plumes, such as those released during quiescent periods or nonexplosive eruptions. The estimation procedure is based on the LOWTRAN 7 radiative transfer code, which the authors use to model the radiance perceived by TIMS as it views the ground through an SO[sub 2] plume. The input to the procedure includes the altitudes of the aircraft and ground, the altitude and thickness of the SO[sub 2] plume, the emissivity of the ground, and altitude profiles of the atmospheric pressure, temperature, and relative humidity. They use the TIMS data to estimate both ground temperatures beneath a plume and SO[sub 2] concentrations within a plume. Applying this procedure to TIMS data acquired over Mount Etna, Sicily, on July 29, 1986, the authors estimate that the SO[sub 2] flux from the volcano was approximately 6700 t d[sup [minus]1]. The use of TIMS to study SO[sub 2] plumes represents a bridge between highly localized methods, such as correlation spectroscopy or direct sampling, and small-scale mapping techniques involving satellite instruments such as the Total Ozone Mapping Spectrometer or Microwave Limb Sounder. The authors require further airborne experiments to refine their estimation procedure. This refinement is a necessary preparation for the scheduled 1998 launch of the Advanced Spaceborne Thermal Emission and Reflectance Radiometer, which will allow large-scale multispectral thermal infrared image data to be collected over virtually any volcano on Earth at least once every 16 days.

  13. The use of multispectral thermal infrared image data to estimate the sulfur dioxide flux from volcanoes: A case study from Mount Etna, Sicily, July 29, 1986

    NASA Technical Reports Server (NTRS)

    Realmuto, Vincent J.; Abrams, Michael J.; Buongiorno, M. Fabrizia; Pieri, David C.

    1994-01-01

    We have found that image data acquired with NASA's airborne Thermal Infrared Multispectral Scanner (TIMS) can be used to make estimates of the SO2 content of volcanic plumes. TIMS image data are most applicable to the study of partially transparent SO2 plumes, such as those released during quiescent periods or nonexplosive eruptions. The estimation procedure is based on the LOWTRAN 7 radiative transfer code, which we use to model the radiance perceived by TIMS as it views the ground through an SO2 plume. The input to the procedure includes the altitudes of the aircraft and ground, the altitude and thickness of the SO2 plume, the emissivity of the ground, and altitude profiles of the atmospheric pressure, temperature, and relative humidity. We use the TIMS data to estimate both ground temperatures beneath a plume and SO2 concentrations within a plume. Applying our procedure to TIMS data acquired over Mount Etna, Sicily, on July 29, 1986, we estimate that the SO2 flux from the volcano was approximately 6700 t d(exp -1). The use of TIMS to study SO2 plumes represents a bridge between highly localized methods, such as correlation spectroscopy or direct sampling, and small-scale mapping techniques involving satellite instruments such as the Total Ozone Mapping Spectrometer or Microwave Limb Sounder. We require further airborne experiments to refine our estimation procedure. This refinement is a necessary preparation for the schedueled 1998 launch of the Advanced Spaceborne Thermal Emission and Reflectance Radiometer, which will allow large-scale multispectral thermal infrared image data to be collected over virtually any volcano on Earth at least once every 16 days.

  14. Identifying hazard parameter to develop quantitative and dynamic hazard map of an active volcano in Indonesia

    NASA Astrophysics Data System (ADS)

    Suminar, Wulan; Saepuloh, Asep; Meilano, Irwan

    2016-05-01

    Analysis of hazard assessment to active volcanoes is crucial for risk management. The hazard map of volcano provides information to decision makers and communities before, during, and after volcanic crisis. The rapid and accurate hazard assessment, especially to an active volcano is necessary to be developed for better mitigation on the time of volcanic crises in Indonesia. In this paper, we identified the hazard parameters to develop quantitative and dynamic hazard map of an active volcano. The Guntur volcano in Garut Region, West Java, Indonesia was selected as study area due population are resided adjacent to active volcanoes. The development of infrastructures, especially related to tourism at the eastern flank from the Summit, are growing rapidly. The remote sensing and field investigation approaches were used to obtain hazard parameters spatially. We developed a quantitative and dynamic algorithm to map spatially hazard potential of volcano based on index overlay technique. There were identified five volcano hazard parameters based on Landsat 8 and ASTER imageries: volcanic products including pyroclastic fallout, pyroclastic flows, lava and lahar, slope topography, surface brightness temperature, and vegetation density. Following this proposed technique, the hazard parameters were extracted, indexed, and calculated to produce spatial hazard values at and around Guntur Volcano. Based on this method, the hazard potential of low vegetation density is higher than high vegetation density. Furthermore, the slope topography, surface brightness temperature, and fragmental volcanic product such as pyroclastics influenced to the spatial hazard value significantly. Further study to this proposed approach will be aimed for effective and efficient analyses of volcano risk assessment.

  15. Embedded ARM System for Volcano Monitoring in Remote Areas: Application to the Active Volcano on Deception Island (Antarctica)

    PubMed Central

    Peci, Luis Miguel; Berrocoso, Manuel; Fernández-Ros, Alberto; García, Alicia; Marrero, José Manuel; Ortiz, Ramón

    2014-01-01

    This paper describes the development of a multi-parameter system for monitoring volcanic activity. The system permits the remote access and the connection of several modules in a network. An embedded ARM™™ processor has been used, allowing a great flexibility in hardware configuration. The use of a complete Linux solution (Debian™) as Operating System permits a quick, easy application development to control sensors and communications. This provides all the capabilities required and great stability with relatively low energy consumption. The cost of the components and applications development is low since they are widely used in different fields. Sensors and commercial modules have been combined with other self-developed modules. The Modular Volcano Monitoring System (MVMS) described has been deployed on the active Deception Island (Antarctica) volcano, within the Spanish Antarctic Program, and has proved successful for monitoring the volcano, with proven reliability and efficient operation under extreme conditions. In another context, i.e., the recent volcanic activity on El Hierro Island (Canary Islands) in 2011, this technology has been used for the seismic equipment and GPS systems deployed, thus showing its efficiency in the monitoring of a volcanic crisis. PMID:24451461

  16. Embedded ARM system for volcano monitoring in remote areas: application to the active volcano on Deception Island (Antarctica).

    PubMed

    Peci, Luis Miguel; Berrocoso, Manuel; Fernández-Ros, Alberto; García, Alicia; Marrero, José Manuel; Ortiz, Ramón

    2014-01-02

    This paper describes the development of a multi-parameter system for monitoring volcanic activity. The system permits the remote access and the connection of several modules in a network. An embedded ARM™ processor has been used, allowing a great flexibility in hardware configuration. The use of a complete Linux solution (Debian™) as Operating System permits a quick, easy application development to control sensors and communications. This provides all the capabilities required and great stability with relatively low energy consumption. The cost of the components and applications development is low since they are widely used in different fields. Sensors and commercial modules have been combined with other self-developed modules. The Modular Volcano Monitoring System (MVMS) described has been deployed on the active Deception Island (Antarctica) volcano, within the Spanish Antarctic Program, and has proved successful for monitoring the volcano, with proven reliability and efficient operation under extreme conditions. In another context, i.e., the recent volcanic activity on El Hierro Island (Canary Islands) in 2011, this technology has been used for the seismic equipment and GPS systems deployed, thus showing its efficiency in the monitoring of a volcanic crisis.

  17. Analysis of Active Figure Control Effects on Mounting Strategy for X-Ray Optics

    NASA Technical Reports Server (NTRS)

    Kolodziejczak, Jeffrey J.; Roche, Jacqueline M.; O'Dell, Stephen L.; Ramsey, Brian D.; Elsner, Ryan F.; Gubarev, Mikhail V.; Weisskopf, Martin C.

    2014-01-01

    As part of ongoing development efforts at MSFC, we have begun to investigate mounting strategies for highly nested x-ray optics in both full-shell and segmented configurations. The analytical infrastructure for this effort also lends itself to investigation of active strategies. We expect that a consequence of active figure control on relatively thin substrates is that errors are propagated to the edges, where they might affect the effective precision of the mounting points. Based upon modeling, we describe parametrically, the conditions under which active mounts are preferred over fixed ones, and the effect of active figure corrections on the required number, locations, and kinematic characteristics of mounting points.

  18. Active Figure Control Effects on Mounting Strategy for X-Ray Optics

    NASA Technical Reports Server (NTRS)

    Kolodziejczak, Jeffery J.; Atkins, Carolyn; Roche, Jacqueline M.; ODell, Stephen L.; Ramsey, Brian D.; Elsner, Ronald F.; Weisskopf, Martin C.; Gubarev, Mikhail V.

    2014-01-01

    As part of ongoing development efforts at MSFC, we have begun to investigate mounting strategies for highly nested xray optics in both full-shell and segmented configurations. The analytical infrastructure for this effort also lends itself to investigation of active strategies. We expect that a consequence of active figure control on relatively thin substrates is that errors are propagated to the edges, where they might affect the effective precision of the mounting points. Based upon modeling, we describe parametrically, the conditions under which active mounts are preferred over fixed ones, and the effect of active figure corrections on the required number, locations, and kinematic characteristics of mounting points.

  19. Risk-Free Volcano Observations Using an Unmanned Autonomous Helicopter: seismic observations near the active vent of Sakurajima volcano, Japan

    NASA Astrophysics Data System (ADS)

    Ohminato, T.; Kaneko, T.; Koyama, T.; Yasuda, A.; Watanabe, A.; Takeo, M.; Honda, Y.; Kajiwara, K.; Kanda, W.; Iguchi, M.; Yanagisawa, T.

    2010-12-01

    Observations in the vicinity of summit area of active volcanoes are important not only for understanding physical processes in the volcanic conduit but also for eruption prediction and volcanic hazards mitigation. It is, however, challenging to install observation sensors near active vents because of the danger of sudden eruptions. We need safe and efficient ways of installing sensors near the summit of active volcanoes. We have been developing an volcano observation system based on an unmanned autonomous vehicle (UAV) for risk-free volcano observations. Our UAV is an unmanned autonomous helicopter manufactured by Yamaha-Motor Co., Ltd. The UAV is 3.6m long and weighs 84kg with maximum payload of 10kg. The UAV can aviate autonomously along a previously programmed path within a meter accuracy using real-time kinematics differential GPS equipment. The maximum flight time and distance from the operator are 90 minutes and 5km, respectively. We have developed various types of volcano observation techniques adequate for the UAV, such as aeromagnetic survey, taking infrared and visible images from onboard high-resolution cameras, volcanic ash sampling in the vicinity of active vents. Recently, we have developed an earthquake observation module (EOM), which is exclusively designed for the UAV installation in the vicinity of active volcanic vent. In order to meet the various requirements for UAV installation, the EOM is very compact, light-weight (5-6kg), and is solar-powered. It is equipped with GPS for timing, a communication device using cellular-phone network, and triaxial accelerometers. Our first application of the EOM installation using the UAV is one of the most active volcanoes in Japan, Sakurajima volcano. Since 2006, explosive eruptions have been continuing at the reopened Showa crater at the eastern flank near the summit of Sakurajima. Entering the area within 2 km from the active craters is prohibited, and thus there were no observation station in the vicinity

  20. Late-stage summit activity of Martian shield volcanoes

    NASA Technical Reports Server (NTRS)

    Mouginis-Mark, P. J.

    1982-01-01

    The preservation of morphologically fresh lava flows which pre-date the most recent episodes of caldera collapse at the summits of Ascraeus, Arsia and Olympus Montes indicates that explosive eruptions were not associated with this stage of Tharsis shield volcanism. The existence of resurfaced floor segments, complex wrinkle ridges, and lava terraces within the summit craters suggests that lava lakes comprised the dominant form of the intra-caldera activity. Multiple collapse episodes on Ascraeus and Olympus Montes are indicated by the nested summit craters. The most plausible cause of caldera collapse appears to be large-scale sub-terminal effusive activity, which is corroborated by the previously recognized existence of large lava flows on the flanks of these volcanoes. Due to the implied sequence of large-scale explosive (silicic) volcanism followed by effusive (basaltic) activity, it appears highly unlikely that ignimbrites or other forms of pyroclastic flows (previously proposed as possible deposits within the Olympus Mons aureole material) were ever erupted from the Tharsis Montes.

  1. Shallow outgassing changes disrupt steady lava lake activity, Kilauea Volcano

    NASA Astrophysics Data System (ADS)

    Patrick, M. R.; Orr, T. R.; Swanson, D. A.; Lev, E.

    2015-12-01

    Persistent lava lakes are a testament to sustained magma supply and outgassing in basaltic systems, and the surface activity of lava lakes has been used to infer processes in the underlying magmatic system. At Kilauea Volcano, Hawai`i, the lava lake in Halema`uma`u Crater has been closely studied for several years with webcam imagery, geophysical, petrological and gas emission techniques. The lava lake in Halema`uma`u is now the second largest on Earth, and provides an unprecedented opportunity for detailed observations of lava lake outgassing processes. We observe that steady activity is characterized by continuous southward motion of the lake's surface and slow changes in lava level, seismic tremor and gas emissions. This normal, steady activity can be abruptly interrupted by the appearance of spattering - sometimes triggered by rockfalls - on the lake surface, which abruptly shifts the lake surface motion, lava level and gas emissions to a more variable, unstable regime. The lake commonly alternates between this a) normal, steady activity and b) unstable behavior several times per day. The spattering represents outgassing of shallowly accumulated gas in the lake. Therefore, although steady lava lake behavior at Halema`uma`u may be deeply driven by upwelling of magma, we argue that the sporadic interruptions to this behavior are the result of shallow processes occurring near the lake surface. These observations provide a cautionary note that some lava lake behavior is not representative of deep-seated processes. This behavior also highlights the complex and dynamic nature of lava lake activity.

  2. Volcano dome dynamics at Mount St. Helens: Deformation and intermittent subsidence monitored by seismicity and camera imagery pixel offsets

    NASA Astrophysics Data System (ADS)

    Salzer, J. T.; Thelen, W. A.; James, M. R.; Walter, T. R.; Moran, S. C.; Denlinger, R. P.

    2015-12-01

    The morphology of a volcanic lava dome and its rate of change play key roles in the estimation of dome stability. While long term variations of dome morphology can be quantified using aerial remote sensing, changes over shorter time scales and smaller spatial scales are more difficult to determine. However, intermittent destabilization of the dome, in particular on flanks of the domes, can be significant. This study focuses on short term deformation associated with earthquakes and tremor at Mount St. Helens, observed over a 6 week period in the summer of 2006. We use Digital Image Correlation (DIC) to compute the displacement field between successive optical images acquired by multiple fixed cameras with clear views of the dome. The results of the these calculations are compared to the occurrence of seismic events. A systematic time-series DIC analysis of image pairs showed no sharp changes in the dome morphology during periods without seismic events. However, the results reveal that the steady dome growth at Mount St. Helens was interrupted by short term displacements reaching magnitudes on the order of a meter. These displacements are only observed in association with low frequency, large magnitude seismic events, followed by tremor with frequencies between 5 Hz and likely exceeding 30 Hz. For selected events that coincide with the timing of the acquisition of an accurate DEM of the crater floor, we reproject the displacement fields obtained from two cameras onto the topography. This enables 3D displacement vectors to be derived, showing that the co-seismic deformation is marked by subsidence of the dome in a segmented fashion, the central region displaying mainly vertical motion, while the displacements on the talus are more slope-parallel. The exact relationship between the recorded seismic energy and the observed deformation of the dome can not be resolved because the cameras were only sampling every 15 - 60 minutes. However, our analysis suggests that the

  3. Introducing a new semi-active engine mount using force controlled variable stiffness

    NASA Astrophysics Data System (ADS)

    Azadi, Mojtaba; Behzadipour, Saeed; Faulkner, Gary

    2013-05-01

    This work introduces a new concept in designing semi-active engine mounts. Engine mounts are under continuous development to provide better and more cost-effective engine vibration control. Passive engine mounts do not provide satisfactory solution. Available semi-active and active mounts provide better solutions but they are more complex and expensive. The variable stiffness engine mount (VSEM) is a semi-active engine mount with a simple ON-OFF control strategy. However, unlike available semi-active engine mounts that work based on damping change, the VSEM works based on the static stiffness change by using a new fast response force controlled variable spring. The VSEM is an improved version of the vibration mount introduced by the authors in their previous work. The results showed significant performance improvements over a passive rubber mount. The VSEM also provides better vibration control than a hydromount at idle speed. Low hysteresis and the ability to be modelled by a linear model in low-frequency are the advantages of the VSEM over the vibration isolator introduced earlier and available hydromounts. These specifications facilitate the use of VSEM in the automotive industry, however, further evaluation and developments are needed for this purpose.

  4. Broadband recording of Strombolian explosions and associated very-long-period seismic signals on Mount Erebus Volcano, Ross Island, Antarctica

    NASA Astrophysics Data System (ADS)

    Rowe, C. A.; Aster, R. C.; Kyle, P. R.; Schlue, J. W.; Dibble, R. R.

    In December 1996 and January 1997, broadband seismometers were deployed on the summit plateau of Mount Erebus at radial distances of 0.7, 1.4 and 1.9 km from the central crater and lava lake. Strombolian explosions at Erebus previously have been observed to produce seismic and acoustic energy between 1 and 6 Hz. New observations document significant energy with spectral peaks as grave as 20 s. Nearly identical very-long-period (VLP) signals begin ∼1.5 s prior to explosions, have dilatational onsets and persist for up to 150 s. Similar VLP waveforms were recorded at all three stations, indicating that the seismograms are essentially source-dominated. Particle motions suggest an initial depth for the VLP source of up to several hundred meters, migrating deeper in the course of ∼15 s. Such explosion-associated VLP signals may indicate a nondestructive lossy resonance or nonlinear fluid-flow excitation within the shallow magmatic system.

  5. Post-traumatic stress disorder among survivors two years after the 2010 Mount Merapi volcano eruption: A survey study.

    PubMed

    Warsini, Sri; Buettner, Petra; Mills, Jane; West, Caryn; Usher, Kim

    2015-06-01

    The Mount Merapi volcanic eruption in October 2010 was one of Indonesia's largest and most recent natural disasters. A cross-sectional study was undertaken to measure the psychosocial impact of the eruption on survivors in two locations in Yogyakarta, Java, Indonesia. The Impact of Event Scale Revised was used to assess participants' symptoms of post-traumatic stress disorder. Post-Traumatic Stress Disorder responses and demographic characteristics were compared in both locations by conducting bivariate analysis using Mann-Whitney and t tests. The relative contributions of demographic variables and psychosocial impact were examined using multiple linear regression analyses. Two years after the eruption, survivors from the area closest to the eruption had significantly higher Impact of Event Scale Revised scores than those in the comparison area. In particular, females, adults between the ages of 18 and 59, and people who owned their own home experienced the highest levels of psychosocial impact. Nurses and other health professionals need to be aware of the impact of natural disasters on survivors and develop interventions to help people adjust to the psychosocial impact of these events.

  6. Influence of particle aggregation on deposition of distal tephra from the May 18, 1980, eruption of Mount St. Helens volcano

    SciTech Connect

    Carey, S.N.; Sigurdsson, H.

    1982-08-10

    The May 18, 1980, eruption of Mount St. Helens (MSH) produced an extensive ashfall deposit in Washington, Idaho, and Montana with a minimum volume of 0.55 km/sup 3/ (tephra). An unusual feature of the deposit is the occurrence of a second thickness maximum 325 km ENE of MSH near Ritzville, Washington. Grain size and component abundance analysis of samples along the main is very fine grained (mean size, 2 ..mu..m), poorly sorted, polymodal, and rich in glass shards and pumice fragments. A computer simulation of ash fallout from an atmospherically dispersed eruption plume was developed to evaluate various hypotheses for the origin of the distal ash characteristics, particularly the thickness versus distance relationship. The model was constrained by observations of the eruption column height, elevation of major ash transport, lateral spreading of the eruption plume, and atmospheric wind structure in the vicinity of MSH. Results of different simulations indicate that the second thickness maximum cannot be attributed to either decreased wind velocities over central Washington or injection of fine ash above the horizontal wind velocity maximum near the tropopause. For the model to fit the observed characteristics of the deposit, significant particle aggregation of ash finer than 63 ..mu..m must be invoked. The best fit occurs when ash less than 63 ..mu..m is aggregated into particles several hundred microns in diameter with a settling velocity of 0.35 m/s. Support for this process comes from the observation and collection of fragile ash clusters of similar size which fell at Pullman, Washington, during the May 18 eruption (Sorem, 1982). The premature fallout of fine ash as particle aggregates is a fundamental process in the origin of the grain size characteristics, variations in component abundances, and thickness versus distance relationship of the May 18 MSH ash fall deposit.

  7. Volcanostratigraphic Study in Constructing Volcano Chronology and Its Implication for Geothermal Resource Estimation; Case Study Mount Sawal, West Java

    NASA Astrophysics Data System (ADS)

    Dermawan, F. A.; Hamka, H.; Malik, R. T. A.; Sianipar, J. Y.; Ramadhan, Q. S.

    2016-09-01

    One of the researches that should be done before carrying out a preliminary survey on the geothermal exploration with a volcanic system or volcanic-hydrothermal is by studying the volcanic stratigraphy. Determining the center of the volcanic eruption and its distribution based on the volcanostratigraphic study will be very helpful in a direct mapping that will be implemented, given that the type and characteristics of volcanic rocks are nearly the same between one source of the eruption and the other. On this case, volcanostratigraphic study had been done on Mount Sawal, where a topographic map with a scale of 1: 100,000 is used to determine the center of eruption of each crowns, while another map with a scale of 1: 50,000 is used to identify the distribution of the monogenetic (Hummock) eruption products and crowns border in detail. It is found approximately three crowns, which are Langlayang, Sawal big crown, Pamokolan, and the Cikucang Hummock that is located on the southern edge of the Langlayang crater. These Hummock and Crowns collection will be grouped into Tasik Bregade. Based on the volcanostratigraphic analysis, DEM, and geology, the chronology of how Tasik Bregade is formed is originally from the Langlayang, Sawal big Crowns, and Pamokolan. Tasik Bregade is classified into sub-mature potential geothermal system, from the analysis results, the potential magnitude of the electrical capacity contained in the system is around 0.74 to 1.24 MWe for 30 years, but further research needs to be done because of the detailed geological and other support data that are still lacking.

  8. Mount St. Augustine volcano fumarole wall rock alteration: Mineralogy, zoning, composition and numerical models of its formation process

    USGS Publications Warehouse

    Getahun, A.; Reed, M.H.; Symonds, R.

    1996-01-01

    Intensely altered wall rock was collected from high-temperature (640??C) and low-temperature (375??C) vents at Augustine volcano in July 1989. The high-temperature altered rock exhibits distinct mineral zoning differentiated by color bands. In order of decreasing temperature, the color bands and their mineral assemblages are: (a) white to grey (tridymite-anhydrite); (b) pink to red (tridymite-hematite-Fe hydroxide-molysite (FeCl3) with minor amounts of anhydrite and halite); and (c) dark green to green (anhydrite-halite-sylvite-tridymite with minor amounts of molysite, soda and potash alum, and other sodium and potassium sulfates). The alteration products around the low-temperature vents are dominantly cristobalite and amorphous silica with minor potash and soda alum, aphthitalite, alunogen and anhydrite. Compared to fresh 1986 Augustine lava, the altered rocks exhibit enrichments in silica, base metals, halogens and sulfur and show very strong depletions in Al in all alteration zones and in iron, alkali and alkaline earth elements in some of the alteration zones. To help understand the origins of the mineral assemblages in altered Augustine rocks, we applied the thermochemical modeling program, GASWORKS, in calculations of: (a) reaction of the 1987 and 1989 gases with wall rock at 640 and 375??C; (b) cooling of the 1987 gas from 870 to 100??C with and without mineral fractionation; (c) cooling of the 1989 gas from 757 to 100??C with and without mineral fractionation; and (d) mixing of the 1987 and 1989 gases with air. The 640??C gas-rock reaction produces an assemblage consisting of silicates (tridymite, albite, diopside, sanidine and andalusite), oxides (magnetite and hercynite) and sulfides (bornite, chalcocite, molybdenite and sphalerite). The 375??C gas-rock reaction produces dominantly silicates (quartz, albite, andalusite, microcline, cordierite, anorthite and tremolite) and subordinate amounts of sulfides (pyrite, chalcocite and wurtzite), oxides (magnetite

  9. Volcanoes and climate

    NASA Technical Reports Server (NTRS)

    Toon, O. B.

    1982-01-01

    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.

  10. Water-quality effects on Baker Lake of recent volcanic activity at Mount Baker, Washington

    USGS Publications Warehouse

    Bortleson, Gilbert Carl; Wilson, Reed T.; Foxworthy, B.L.

    1976-01-01

    Increased volcanic activity on Mount Baker, which began in March 1975, represents the greatest known activity of a Cascade Range volcano since eruptions at Lassen Peak, Calif. during 1914-17. Emissions of dust and increased emanations of steam, other gases, and heat from the Sherman Crater area of the mountain focused attention on the possibility of hazardous events, including lava flows, pyroclastic eruptions, avalanches, and mudflows. However, the greatest undesirable natural results that have been observed after one year of the increased activity are an increase in local atmospheric pollution and a decrease in the quality of some local water resources, including Baker Lake. Baker Lake, a hydropower reservoir behind Upper Baker Dam, supports a valuable fishery resource and also is used for recreation. The lake's feedwater is from Baker River and many smaller streams, some of which, like Boulder Creek, drain parts of Mount Baker. Boulder Creek receives water from Sherman Crater, and its channel is a likely route for avalanches or mudflows that might originate in the crater area. Boulder Creek drains only about 5 percent of the total drainage area of Baker Lake, but during 1975 carried sizeable but variable loads of acid and dissolved minerals into the lake. Sulfurous gases and the fumarole dust from Sherman Crater are the main sources for these materials, which are brought into upper Boulder Creek by meltwater from the crater. In September 1973, before the increased volcanic activity, Boulder Creek near the lake had a pH of 6.0-6.6; after the increase the pH ranged as low as about 3.5. Most nearby streams had pH values near 7. On April 29, in Boulder Creek the dissolved sulfate concentration was 6 to 29 times greater than in nearby creeks or in Baker River; total iron was 18-53 times greater than in nearby creeks; and other major dissolved constituents generally 2 to 7 times greater than in the other streams. The short-term effects on Baker Lake of the acidic

  11. Reawakening of a volcano: Activity beneath Eyjafjallajökull volcano from 1991 to 2009

    NASA Astrophysics Data System (ADS)

    Hjaltadóttir, Sigurlaug; Vogfjörd, Kristín S.; Hreinsdóttir, Sigrún; Slunga, Ragnar

    2015-10-01

    The ice-capped Eyjafjallajökull volcano, south Iceland, had been dormant for 170 years when the first signs of reawakening of the volcano were captured by seismic and geodetic measurements in 1994. These were the first clear observed signs of unrest followed by 16 years of intermittent magmatic unrest culminating in 2010 when two eruptions broke out on the flank and at the summit. We analyze seismic data from 1991 through 2008 and GPS data from 1992 to May 2009 to infer magma movements beneath the volcano. The relocated earthquakes reveal an overall pipe-like pattern northeast of the summit crater, sporadically mapping the pathway of magma from the base of the crust towards an intrusion in the upper crust. During the study period, three major seismic swarms were recorded. Two of them, in 1994 and 1999-2000, occurred in the upper and intermediate crust and accompanied crustal deformation centered at the southeastern flank. No uplift was detected during the 19- to 25-km-deep 1996 swarm, near the crust-mantle boundary, but the horizontal, ~ E-W oriented T-axes indicate a period of tension/opening, suggesting magma intruding up into the base of the crust. The GPS measured deformation during 1999-2000 can be modeled as intrusion of a horizontal, circular sill with volume of 0.030 ± 0.007 km3 at 5.0 ± 1.3 km depth. The less constrained 4.5- to 5-km-deep sill model for the 1994 episode indicates a three times smaller intruded volume (0.011 km3) than during 1999-2000. In the years between/following the intrusions, contraction was observed at the southeastern flank. The contraction from 2000.5 to 2009.3 can be fitted by a circular sill model with a volume contraction of - 0.0015 ± 0.0003 km3/year at 5.5 ± 2.0 km depth. The less well constrained model for 1994.7 to 1998.6 gives a volume contraction of -(0.0009-0.0010) km3 at a fixed depth of 5 km. The accumulated volume changes (~- 0.013 km3 for the second period, ~ 0.0037 km3 for the first period) are much larger than

  12. Reventador Volcano 2005: Eruptive activity inferred from seismo-acoustic observation

    NASA Astrophysics Data System (ADS)

    Lees, Jonathan M.; Johnson, Jeffrey B.; Ruiz, Mario; Troncoso, Liliana; Welsh, Matt

    2008-09-01

    Reventador Volcano entered an eruptive phase in 2005 which included a wide variety of seismic and infrasonic activity. These are described and illustrated: volcano-tectonic, harmonic tremor, drumbeats, chugging and spasmodic tremor, long period and very long period events. The recording of this simultaneous activity on an array of three broadband, seismo-acoustic instruments provides detailed information of the state of the conduit and vent during this phase of volcanic eruption. Quasi-periodic tremor at Reventador is similar to that observed at other volcanoes and may be used as an indicator of vent aperture. Variations in the vibration modes of the volcano, frequency fluctuations and rapid temporal fluctuations suggest the influx of new material, choking of the vent and possible modification of the conduit geometry during explosions and effusion over a period of six weeks.

  13. Absolute and relative locations of earthquakes at Mount St. Helens, Washington, using continuous data: implications for magmatic processes: Chapter 4 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Thelen, Weston A.; Crosson, Robert S.; Creager, Kenneth C.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    This study uses a combination of absolute and relative locations from earthquake multiplets to investigate the seismicity associated with the eruptive sequence at Mount St. Helens between September 23, 2004, and November 20, 2004. Multiplets, a prominent feature of seismicity during this time period, occurred as volcano-tectonic, hybrid, and low-frequency earthquakes spanning a large range of magnitudes and lifespans. Absolute locations were improved through the use of a new one-dimensional velocity model with excellent shallow constraints on P-wave velocities. We used jackknife tests to minimize possible biases in absolute and relative locations resulting from station outages and changing station configurations. In this paper, we show that earthquake hypocenters shallowed before the October 1 explosion along a north-dipping structure under the 1980-86 dome. Relative relocations of multiplets during the initial seismic unrest and ensuing eruption showed rather small source volumes before the October 1 explosion and larger tabular source volumes after October 5. All multiplets possess absolute locations very close to each other. However, the highly dissimilar waveforms displayed by each of the multiplets analyzed suggest that different sources and mechanisms were present within a very small source volume. We suggest that multiplets were related to pressurization of the conduit system that produced a stationary source that was highly stable over long time periods. On the basis of their response to explosions occurring in October 2004, earthquakes not associated with multiplets also appeared to be pressure dependent. The pressure source for these earthquakes appeared, however, to be different from the pressure source of the multiplets.

  14. Analysis of Active Lava Flows on Kilauea Volcano, Hawaii, Using SIR-C Radar Correlation Measurements

    NASA Technical Reports Server (NTRS)

    Zebker, H. A.; Rosen, P.; Hensley, S.; Mouginis-Mark, P. J.

    1995-01-01

    Precise eruption rates of active pahoehoe lava flows on Kilauea volcano, Hawaii, have been determined using spaceborne radar data acquired by the Space Shuttle Imaging Radar-C (SIR-C). Measurement of the rate of lava flow advance, and the determination of the volume of new material erupted in a given period of time, are among the most important observations that can be made when studying a volcano.

  15. Use of SAR data to study active volcanoes in Alaska

    USGS Publications Warehouse

    Dean, K.G.; Engle, K.; Lu, Zhiming; Eichelberger, J.; Neal, T.; Doukas, M.

    1996-01-01

    Synthetic Aperture Radar (SAR) data of Westdahl, Veniaminof, and Novarupta volcanoes in the Aleutian Arc of Alaska were analyzed to investigate recent surface volcanic processes. These studies support ongoing monitoring and research by the Alaska Volcano Observatory (AVO) in the North Pacific Ocean Region. Landforms and possible crustal deformation before, during, or after eruptions were detected and analyzed using data from the European Remote Sensing Satellites (ERS), Japanese Earth Resources Satellite (JERS) and the U. S. Seasat platforms. Field observations collected by scientists from the AVO were used to verify the results from the analysis of SAR data.

  16. Use of SAR data to study active volcanoes in Alaska

    USGS Publications Warehouse

    Dean, K.G.; Engle, K.; Lu, Zhiming; Eichelberger, J.; Near, T.; Doukas, M.

    1996-01-01

    Synthetic Aperture Radar (SAR) data of the Westdahl, Veniaminof, and Novarupta volcanoes in the Aleutian Arc of Alaska were analysed to investigate recent surface volcanic processes. These studies support ongoing monitoring and research by the Alaska Volcano Observatory (AVO) in the North Pacific Ocean Region. Landforms and possible crustal deformation before, during, or after eruptions were detected and analysed using data from the European Remote Sensing Satellites (ERS), the Japanese Earth Resources Satellite (JERS) and the US Seasat platforms. Field observations collected by scientists from the AVO were used to verify the results from the analysis of SAR data.

  17. A novel design of semi-active hydraulic mount with wide-band tunable notch frequency

    NASA Astrophysics Data System (ADS)

    Wang, Min; Yao, Guo-feng; Zhao, Jing-zhou; Qin, Min

    2014-04-01

    Hydraulic engine mount is advanced vibration isolator with superior performance to reduce vibration transferred from engine to chassis. As the stiffness at notch frequency is small, some semi-active or active hydraulic mounts tune some parameters to let notch frequency coincide with exciting frequency for better vibration isolation performance. It is discovered the current semi-active mounts can tune the notch frequency in narrow frequency band when only one parameter is tuned. A novel semi-active hydraulic engine mount design which introduces screw thread is proposed and researched in the paper. This hydraulic mount can control both cross section area and the length of inertia track and the theoretical tunable notch frequency band is [0, ∞). Theoretical work is carried out to uncover the capability for the proposed design to tune notch frequency. Simulation work is performed to understand its high vibration isolation performance. For the purpose of energy conservation, the friction self-locking is introduced. This denotes once the mount is tuned at optimal condition, the energy can be cut off and the optimal condition will never change. We also determine the best time to tune the parameters of the proposed mount in order to decrease the acting force. The proposed semi-active mount has capability to obtain wide band tunable notch frequency and has merit of energy conservation.

  18. Geologic map of Medicine Lake volcano, northern California

    USGS Publications Warehouse

    Donnelly-Nolan, Julie M.

    2011-01-01

    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.

  19. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2002

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Moran, Seth C.; Sánchez, John; Estes, Steve; McNutt, Stephen R.; Paskievitch, John

    2003-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at historically active volcanoes in Alaska since 1988 (Power and others, 1993; Jolly and others, 1996; Jolly and others, 2001; Dixon and others, 2002). The primary objectives of this program are the seismic monitoring of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog presents the basic seismic data and changes in the seismic monitoring program for the period January 1, 2002 through December 31, 2002. Appendix G contains a list of publications pertaining to seismicity of Alaskan volcanoes based on these and previously recorded data. The AVO seismic network was used to monitor twenty-four volcanoes in real time in 2002. These include Mount Wrangell, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Katmai Volcanic Group (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin), Aniakchak Crater, Mount Veniaminof, Pavlof Volcano, Mount Dutton, Isanotski Peaks, Shishaldin Volcano, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin Volcano, Great Sitkin Volcano, and Kanaga Volcano (Figure 1). Monitoring highlights in 2002 include an earthquake swarm at Great Sitkin Volcano in May-June; an earthquake swarm near Snowy Mountain in July-September; low frequency (1-3 Hz) tremor and long-period events at Mount Veniaminof in September-October and in December; and continuing volcanogenic seismic swarms at Shishaldin Volcano throughout the year. Instrumentation and data acquisition highlights in 2002 were the installation of a subnetwork on Okmok Volcano, the establishment of telemetry for the Mount Veniaminof subnetwork, and the change in the data acquisition system to

  20. Fifteen years of thermal activity at Vanuatu's volcanoes (2000-2015) revealed by MIROVA

    NASA Astrophysics Data System (ADS)

    Coppola, D.; Laiolo, M.; Cigolini, C.

    2016-08-01

    The Vanuatu archipelago consists of 80 islands and hosts 5 subaerial volcanoes (Yasur, Lopevi, Ambrym, Aoba and Gaua) that have shown sign of activity during the past decade. In this contribution we provide a 15 years-long datasets (2000-2015) of the thermal activity recorded at these active volcanoes by means of MIROVA (Middle InfraRed Observation of Volcanic Activity) a new volcanic hotspot detection system based on MODIS data. The analyzed volcanoes are characterized by a spectrum of volcanic activities whose thermal signature has been tracked and carefully analyzed. These include strombolian-vulcanian explosions at Yasur, lava flows at Lopevi, lava lakes at Ambrym, surtseyan-type eruptions within the Voui crater lake of Aoba and ash-dominated eruptions with strong degassing at Gaua. The collected data reveal several details of the long term eruptive dynamics at single sites such as a monthly long pulse in thermal emissions at Yasur volcano as well as at the two active craters of Ambrym (Benbow and Marum). Heating cycles within Aoba crater lake and intermittent pressurized eruptions at Lopevi volcano has also been detected and shed light in the eruptive dynamics of the analyzed volcanoes. In addition we were able to track a two years long intensification of thermal output at Benbow crater (Ambrym) that preceded the occurrence of the first intra-caldera eruptions of this volcano since 1989. We emphasize how the data provided by MIROVA represent a new, safe and affordable method for monitoring in near-real time a large spectrum of volcanic activities taking place at Vanuatu and other volcanic areas.

  1. Pleistocene Paleoclimatic Features at Mount Mazama Volcano and the Crater Lake Region, Oregon, Dated by Ar Geochronology

    NASA Astrophysics Data System (ADS)

    Bacon, C. R.; Lanphere, M. A.

    2005-12-01

    Fifteen examples of the interplay between glacial ice and magma or volcanic rock in the Crater Lake region have been dated by K-Ar or 40Ar/39Ar. Ages of glacial features compare well with times of extensive ice presence implied by marine oxygen isotope stages (MIS; Bassinot et al. 1994 EPSL 126:91-108). Prior to the 7.7-ka caldera-forming eruption, the summit of Mount Mazama was 3700 m asl. Moraines of the last glacial maximum (LGM) reached as low as 1400 m. Late MIS 10 glaciation is recorded at 1900-2000 m: in the SE caldera wall, glaciated andesite (340±6, 341±8 ka; 1σ) is overlain by intracanyon dacite (306±5 ka); in the E wall, similar glaciated andesite underlies till capped by dacite (336±6 ka); on the SW lakeshore, glaciated dacite (351±12 ka) is overlain by andesite (302±10 ka). Early MIS 8 is represented 276±11-ka dacite of Munson Ridge that implies >170 m of ice at 2040 m. In late MIS 8 or in MIS 7.4, voluminous andesite of Applegate Peak (7 ages 269±12 to 211±16 ka) chilled against thick ice along the E edge of Sun Creek valley at 1850 m and higher. Andesite of Garfield Peak (224±9 ka; 2100-2400 m) flowed over andesite (269±12 ka) glaciated during MIS 8.0 or 7.4. North of Castle Creek at 1740 m dacite (216±4 ka) lies on andesite (258±7 ka) glaciated in MIS 7.4 or 8.0. Andesite of Roundtop (159±13 ka) extending 3 km NE of the caldera rim is an MIS 6 ice-bounded lava flow. At Pumice Point, polygonal jointing and breccia occur in thick andesite (117±3 ka) that rests on glaciated (1900 m) mafic andesite (122±20 ka); the andesite is overlain by subaerial dacite (116±5 ka). Although the mafic andesite could have been glaciated in MIS 6, ice-contact/meltwater chilling of the overlying andesite probably dates from MIS 5.4. Below Llao Rock, andesite (70±4 ka) caps sediments deposited on dacite (116±9 ka) during MIS 5.4-4. Andesite (87±15 ka) from a subaerial cone (base 1900 m) ESE of Mazama flowed into ice-free Scott Creek during MIS 5

  2. Geological and InSAR surveys highlight tectonic hazard in densely inhabited areas on the lower southeastern flank of Mount Etna volcano, Italy

    NASA Astrophysics Data System (ADS)

    Neri, Marco; Sansosti, Eugenio; Casu, Francesco; Leonardi, Anna; Pepe, Antonio; Pepe, Susi; Solaro, Giuseppe

    2015-04-01

    A constant seaward sliding mechanism is affecting the eastern to southern flanks of Mt. Etna volcano, involving an overall on-shore area of >700 km2.The margins of this unstable area are marked by the Pernicana Fault System to the north and the Ragalna Fault System to the south-west. The unstable area is divided into several blocks characterized by different kinematics and delimited by active faults crossing, in several cases, urban areas, towns and villages. One of these structural discontinuities is the Trecastagni-S.G.La Punta-Aci Trezza fault system, a tectonic structure extending from the volcano summit (where it trends NNW-SSE), to the lower southeastern flank (trending NW-SE) and reaching the coast at the Aci Trezza village (WNW-ESE and E-W). The last segment of this tectonic system crosses several important roads and man-made structures within Aci Trezza, and continues for a few kilometers off-shore crossing the Faraglioni stacks-Lachea island. Recently, analysis of long-period InSAR data has added some details to the sliding motion on the lower south-eastern flank of the volcano, particularly on the S.G.La Punta-Aci Trezza fault segments. Field geological and instrumental data confirmed the slip activity and the extension of the tectonically disturbed areas, highlighting a transition zone between the two main fault segments. On the other hand, some of the features detected by InSAR are not clearly visible in the field and were never detected before by classical geological surveys. These results are of crucial importance in terms of hazard related to tectonic movements, especially in densely inhabited zones such as the south-eastern flank of Etna, where more than half a million people live. The structural details obtained through these kinds of studies may guide future land use planning appropriately also within towns and villages, where aseismic and seismogenic very active faults are evident at the surfaces.

  3. Magma ascent and the pressurization of Mount Etna's volcanic system.

    PubMed

    Patanè, Domenico; De Gori, Pasquale; Chiarabba, Claudio; Bonaccorso, Alessandro

    2003-03-28

    After a period of deflation during the 1991-1993 flank eruption, Mount Etna underwent a rapid inflation. Seismicity and ground deformation show that since 1994, a huge volume of magma intruded beneath the volcano, producing from 1998 onward a series of eruptions at the summit and on the flank of the volcano. The last of these, started on 27 October 2002, is still in progress and can be considered one of the most explosive eruptions of the volcano in recent times. Here we show how geodetic data and seismic deformation, between 1994 and 2001, indicate a radial compression around an axial intrusion, consistent with a repressurization of Mount Etna's plumbing system at a depth of 6 to 15 kilometers, which triggered most of the seismicity and provoked the dilatation of the volcano and the recent explosive eruptive activity.

  4. The stratigraphy, depositional processes, and environment of the late Pleistocene Polallie-period deposits at Mount Hood Volcano, Oregon, USA

    NASA Astrophysics Data System (ADS)

    Thouret, Jean-Claude

    2005-08-01

    The Polallie eruptive period of Mt. Hood, Oregon, is the last major episode of eruption and dome growth, before the late Holocene activity which was centered at Crater Rock. A volume of 4-8 km 3 of Polallie deposits forms an apron of ca. 60 km 2 on the east, northeast and southeast flanks. The Polallie deposits can be divided, stratigraphically, into four groups: Group I rockslide avalanche and pyroclastic-flow deposits; Group II debris-flow and pyroclastic-flow deposits that suggest some explosive activity and remobilization of pyroclastic debris in a glacial environment; Group III block-and-ash flow deposits that attest to summit dome growth; Group IV alternating debris-flow deposits, glacial sediments, and reworked pyroclastic-flow deposits that indicate a decrease in dome activity and an increase in erosion and transport. Group III clearly indicates frequent episodes of dome growth and collapse, whereas Groups II and IV imply increasing erosion and, conversely, decreasing volcanic activity. The Polallie period occurred in the late Pleistocene during and just after the last Alpine glaciation, which is named Evans Creek in the Cascade Range. According to four K-Ar age dates on lava flows interbedded with Polallie deposits and to published minimum 14C ages on tephra and soils overlying these deposits, the Polallie period had lasted 15,000-22,000 years between 28-34 ka and 12-13 ka. From stratigraphic subdivisions, sedimentary lithofacies and features and from the grain-size and geochemical data, we infer that the Polallie depositional record is a result of the interplay of several processes acting during a long-lasting period of dome growth and destruction. The growth of several domes near the present summit was intermittent, because each group of sediments encompasses primary (pyroclastic) and secondary (volcaniclastic and epiclastic) deposition. Direct deposition of primary material has occurred within intervals of erosion that have probably included meltwater

  5. Assessment of increased thermal activity at Mount Baker, Washington, March 1975-March 1976

    USGS Publications Warehouse

    Frank, David; Meier, Mark Frederick; Swanson, Donald A.; with contributions by Babcock, James W.; Fretwell, Marvin O.; Malone, Stephen D.; Rosenfeld, Charles L.; Shreve, Ronald L.; Wilcox, Ray E.

    1977-01-01

    In March 1975 Mount Baker showed a large increase in thermal emission, which has persisted for more than 1 year. Fumarole ejecta accompanied the thermal activity from March to September, but the ejecta had no constituents that suggest a magmatic source. Estimates of that part of the total heat flux that would account for the observed snow and ice loss show that the heat-flow increase was roughly one order of magnitude, from about 2 megawatts at 10 watts per square meter, averaged over Sherman Crater before 1975, to about 30 megawatts at 180 watts per square meter, during 1975. Almost half of the glacier that occupied the basin of Sherman Crater was melted in 1975. The new activity generated great concern among the public and the government agencies responsible for geological evaluation of potential hazards and for protection of life and property. The past geologic history, current topography, rock alteration, and location of major fumarolic activity indicate that large rock avalanches and mudflows on the east slope in Boulder Creek valley are the potential hazards of most significance related to present conditions. The most probable types of large mass movements would be mudflows, having speeds of as much as 50 kilometers per hour, that would originate from mixtures of snow, ice, and melt water and avalanches of structurally weak clay-rich rocks that make up the rim of Sherman Crater. Similar mudflows from the volcano have traveled at least 12 kilometers 8 times during the past 10,000 years. A possible worst case event, however, might be a larger, air-cushioned avalanche of as much as 20 to 30 million cubic meters that could hit Baker Lake at speeds of more than 300 kilometers per hour and generate a wave of water large enough to overtop Upper Baker Dam. At least 30 million cubic meters of potentially unstable material occurs as hydrothermally altered remnants of the rim of Sherman Crater and could provide the required volume for the estimated worst case event or

  6. Tilt networks of Mount Shasta and Lassen Peak, California

    USGS Publications Warehouse

    Dzurisin, Daniel; Johnson, Daniel J.; Murray, T.L.; Myers, Barbara

    1982-01-01

    In response to recent eruptions at Mount St. Helens and with support from the USGS Volcanic Hazards Program, the Cascades Volcano Observatory (CVO) has initiated a program to monitor all potentially-active volcanoes of the Cascade Range. As part of that effort, we installed tilt networks and obtained baseline measurements at Mount Shasta and Lassen Peak, California during July 1981. At the same time, baseline electronic distance measurements (EDM) were made and fumarole surveys were conducted by other crews from CVO. Annual surveys are planned initially, with subsequent visits as conditions warrant. These geodetic and geochemical measurements supplement a program of continuous seismic monitoring of Cascade volcanoes by the USGS Office of Earthquake Studies in cooperation with local universities. Other tilt networks were established at Mount Baker in 1975 and at Mount St. Helens in 1981. EDM networks were established at Mount Baker in 1975, Mount St. Helens in 1980, and Crater Lake in 1981. Additional tilt and/or EDM networks are planned for Mount Rainier, Mount Hood, Glacier Peak, Three Sisters, and Crater Lake as funds permit.

  7. Geochemical precursors to volcanic activity at Mount St. Helens, USA.

    PubMed

    Berlo, Kim; Blundy, Jon; Turner, Simon; Cashman, Kathy; Hawkesworth, Chris; Black, Stuart

    2004-11-12

    The importance of the interplay between degassing and crystallization before and after the eruption of Mount St. Helens (Washington, USA) in 1980 is well established. Here, we show that degassing occurred over a period of decades to days before eruptions and that the manner of degassing, as deduced from geochemical signatures within the magma, was characteristic of the eruptive style. Trace element (lithium) and short-lived radioactive isotope (lead-210 and radium-226) data show that ascending magma stalled within the conduit, leading to the accumulation of volatiles and the formation of lead-210 excesses, which signals the presence of degassing magma at depth.

  8. 2010 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Neal, Christina A.; Herrick, Julie; Girina, O.A.; Chibisova, Marina; Rybin, Alexander; McGimsey, Robert G.; Dixon, Jim

    2014-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, volcanic unrest or suspected unrest at 12 volcanic centers in Alaska during 2010. The most notable volcanic activity consisted of intermittent ash emissions from long-active Cleveland volcano in the Aleutian Islands. AVO staff also participated in hazard communication regarding eruptions or unrest at seven volcanoes in Russia as part of an ongoing collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  9. Characterization of Multilayer Piezoelectric Actuators for Use in Active Isolation Mounts

    NASA Technical Reports Server (NTRS)

    Wise, Stephanie A.; Hooker, Matthew W.

    1997-01-01

    Active mounts are desirable for isolating spacecraft science instruments from on-board vibrational sources such as motors and release mechanisms. Such active isolation mounts typically employ multilayer piezoelectric actuators to cancel these vibrational disturbances. The actuators selected for spacecraft systems must consume minimal power while exhibiting displacements of 5 to 10 micron under load. This report describes a study that compares the power consumption, displacement, and load characteristics of four commercially available multilayer piezoelectric actuators. The results of this study indicate that commercially available actuators exist that meet or exceed the design requirements used in spacecraft isolation mounts.

  10. Road guide to volcanic deposits of Mount St. Helens and vicinity, Washington

    USGS Publications Warehouse

    Doukas, Michael P.

    1990-01-01

    Mount St. Helens, the most recently active and most intensively studied Cascades volcano, is in southwestern Washington. The volcano is a superb outdoor laboratory for studying volcanic processes, deposits of observed events, and deposits whose origins are inferred by classic geologic techniques, including analogy to recent deposits. During the past 4,500 years, Mount St. Helens has been more active and more explosive than any other volcano in the conterminous United States. Mount St. Helens became active in mid-March 1980, and eruptive activity began on March 27. Since the climactic eruption of May 18, 1980, the volcano has continued to be active at least until 1988. The 1890 activity of Mount St. Helens is summarized in U.S. Geological Survey Professional Papers 1249 and 1250. This road guide is a tour of Mount St. Helens volcano and vicinity, with emphasis on the effects and deposits of the 1980 eruption. The road log starts from the U.S. Geological Survey's David A. Johnston Cascades Volcano Observatory, Vancouver, Washington. The guide is organized around two primary routes. LEG I is on paved and gravel roads from Vancouver to areas east of Mount St. Helens, including Windy Ridge Overlook near Spirit Lake. This is possibly the most scenic route described in the guide, including a transect of the devastated zone of May 18, 1980, Spirit Lake, and numerous vistas of the volcano. LEG II leads to areas west of the volcano from Vancouver via U.S. Interstate Highway 5, then on a paved ... road along the Toutle River. Highlights include the spectacular effects of mudflows and a view of the huge debris-avalanche deposit that was formed on May 18, 1980.

  11. Optimization of Passive and Active Non-Linear Vibration Mounting Systems Based on Vibratory Power Transmission

    NASA Astrophysics Data System (ADS)

    Royston, T. J.; Singh, R.

    1996-07-01

    While significant non-linear behavior has been observed in many vibration mounting applications, most design studies are typically based on the concept of linear system theory in terms of force or motion transmissibility. In this paper, an improved analytical strategy is presented for the design optimization of complex, active of passive, non-linear mounting systems. This strategy is built upon the computational Galerkin method of weighted residuals, and incorporates order reduction and numerical continuation in an iterative optimization scheme. The overall dynamic characteristics of the mounting system are considered and vibratory power transmission is minimized via adjustment of mount parameters by using both passive and active means. The method is first applied through a computational example case to the optimization of basic passive and active, non-linear isolation configurations. It is found that either active control or intentionally introduced non-linearity can improve the mount's performance; but a combination of both produces the greatest benefit. Next, a novel experimental, active, non-linear isolation system is studied. The effect of non-linearity on vibratory power transmission and active control are assessed via experimental measurements and the enhanced Galerkin method. Results show how harmonic excitation can result in multiharmonic vibratory power transmission. The proposed optimization strategy offers designers some flexibility in utilizing both passive and active means in combination with linear and non-linear components for improved vibration mounts.

  12. Volcanoes: Nature's Caldrons Challenge Geochemists.

    ERIC Educational Resources Information Center

    Zurer, Pamela S.

    1984-01-01

    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.…

  13. Active volcanoes observed through Art: the contribution offered by the social networks

    NASA Astrophysics Data System (ADS)

    Neri, Marco; Neri, Emilia

    2015-04-01

    Volcanoes have always fascinated people for the wild beauty of their landscapes and also for the fear that they arouse with their eruptive actions, sometimes simply spectacular, but other times terrifying and catastrophic for human activities. In the past, volcanoes were sometimes imagined as a metaphysical gateway to the otherworld; they have inspired the creation of myths and legends ever since three thousand years ago, also represented by paintings of great artistic impact. Modern technology today offers very sophisticated and readily accessed digital tools, and volcanoes continue to be frequently photographed and highly appreciated natural phenomena. Moreover, in recent years, the spread of social networks (Facebook, Twitter, YouTube, Instagram, etc.) have made the widespread dissemination of graphic contributions even easier. The result is that very active and densely inhabited volcanoes such as Etna, Vesuvius and Aeolian Islands, in Italy, have become among the most photographed subjects in the world, providing a popular science tool with formidable influence and usefulness. The beauty of these landscapes have inspired both professional artists and photographers, as well as amateurs, who compete in the social networks for the publication of the most spectacular, artistic or simply most informative images. The end result of this often frantic popular scientific activity is at least two-fold: on one hand, it provides geoscientists and science communicators a quantity of documentation that is almost impossible to acquire through the normal systems of volcano monitoring, while on the other it raises awareness and respect for the land among the civil community.

  14. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1, 1994 through December 31, 1999

    USGS Publications Warehouse

    Jolly, Arthur D.; Stihler, Scott D.; Power, John A.; Lahr, John C.; Paskievitch, John; Tytgat, Guy; Estes, Steve; Lockhart, Andrew B.; Moran, Seth C.; McNutt, Stephen R.; Hammond, William R.

    2001-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska - Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained a seismic monitoring program at potentially active volcanoes in Alaska since 1988 (Power and others, 1993; Jolly and others, 1996). The primary objectives of this program are the seismic surveillance of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism.Between 1994 and 1999, the AVO seismic monitoring program underwent significant changes with networks added at new volcanoes during each summer from 1995 through 1999. The existing network at Katmai –Valley of Ten Thousand Smokes (VTTS) was repaired in 1995, and new networks were installed at Makushin (1996), Akutan (1996), Pavlof (1996), Katmai - south (1996), Aniakchak (1997), Shishaldin (1997), Katmai - north (1998), Westdahl, (1998), Great Sitkin (1999) and Kanaga (1999). These networks added to AVO's existing seismograph networks in the Cook Inlet area and increased the number of AVO seismograph stations from 46 sites and 57 components in 1994 to 121 sites and 155 components in 1999. The 1995–1999 seismic network expansion increased the number of volcanoes monitored in real-time from 4 to 22, including Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Mount Snowy, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin, Aniakchak Crater, Pavlof Volcano, Mount Dutton, Isanotski volcano, Shisaldin Volcano, Fisher Caldera, Westdahl volcano, Akutan volcano, Makushin Volcano, Great Sitkin volcano, and Kanaga Volcano (see Figures 1-15). The network expansion also increased the number of earthquakes located from about 600 per year in1994 and 1995 to about 3000 per year between 1997 and 1999.Highlights of the catalog period include: 1) a large volcanogenic seismic

  15. A robust vibration control for a multi-active mount system subjected to broadband excitation

    NASA Astrophysics Data System (ADS)

    Nguyen, Vien-Quoc; Choi, Seung-Bok

    2011-05-01

    In this study, a frequency-shaped sliding mode control design is presented for the robust vibration control of a multi-active mount system in the presence of parametric uncertainties whose upper bounds are assumed to be known. The proposed mount system consists of four active mounts supporting vibration-sensitive equipment. Each active mount—constituted of a rubber element, an inertial mass and two piezostack actuators connected in serial configuration—can be modeled as a two-stage vibration isolator. After formulating the governing equations of motions of the mount system, a desired dynamic is specified in the frequency domain, and control laws are then derived to drive the system dynamics to the desired one based on Lyapunov's theorem. Simulations are performed in the frequency range from 100 to 1000 Hz in order to evaluate the effectiveness of the active mount system associated with the frequency-shaped sliding mode controller. It is demonstrated that the dynamic of the active mount system can approach the desired dynamic as the controller is activated. It also shown that robust vibration control performance is achieved in the presence of the parametric uncertainties.

  16. 2009 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Neal, Christina A.; Girina, Olga A.; Chibisova, Marina; Rybin, Alexander

    2014-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, volcanic unrest, and reports of unusual activity at or near eight separate volcanic centers in Alaska during 2009. The year was highlighted by the eruption of Redoubt Volcano, one of three active volcanoes on the western side of Cook Inlet and near south-central Alaska's population and commerce centers, which comprise about 62 percent of the State's population of 710,213 (2010 census). AVO staff also participated in hazard communication and monitoring of multiple eruptions at ten volcanoes in Russia as part of its collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  17. Use of thermal infrared imaging for monitoring renewed dome growth at Mount St. Helens, 2004: Chapter 17 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Schneider, David J.; Vallance, James W.; Wessels, Rick L.; Logan, Matthew; Ramsey, Michael S.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    A helicopter-mounted thermal imaging radiometer documented the explosive vent-clearing and effusive phases of the eruption of Mount St. Helens in 2004. A gyrostabilized gimbal controlled by a crew member housed the radiometer and an optical video camera attached to the nose of the helicopter. Since October 1, 2004, the system has provided thermal and video observations of dome growth. Flights conducted as frequently as twice daily during the initial month of the eruption monitored rapid changes in the crater and 1980-86 lava dome. Thermal monitoring decreased to several times per week once dome extrusion began. The thermal imaging system provided unique observations, including timely recognition that the early explosive phase was phreatic, location of structures controlling thermal emissions and active faults, detection of increased heat flow prior to the extrusion of lava, and recognition of new lava extrusion. The first spines, 1 and 2, were hotter when they emerged (maximum temperature 700-730°C) than subsequent spines insulated by as much as several meters of fault gouge. Temperature of gouge-covered spines was about 200°C where they emerged from the vent, and it decreased rapidly with distance from the vent. The hottest parts of these spines were as high as 500-730°C in fractured and broken-up regions. Such temperature variation needs to be accounted for in the retrieval of eruption parameters using satellite-based techniques, as such features are smaller than pixels in satellite images.

  18. Prokaryotic diversity of an active mud volcano in the Usu City of Xinjiang, China.

    PubMed

    Yang, Hong-Mei; Lou, Kai; Sun, Jian; Zhang, Tao; Ma, Xiao-Long

    2012-02-01

    The Usu mud volcanoes are the largest group of terrestrial mud volcanoes in China. The volcanoes are located in a typical arid and semi-arid region, and the group consists of 36 erupting active mud volcanoes. In this study, the prokaryotic diversity and community structure in the sediment of an active mud volcano were investigated by constructing bacterial and archaeal clone libraries of the 16S rRNA gene. A total of 100 bacterial and 100 archaeal clones were analysed and found to comprise 11 and 7 distinct phylotypes, respectively. The bacterial phylotypes were classified into three phyla (Proteobacteria, Actinobacteria, and Fusobacteria). Of these, Proteobacteria were the most abundant bacterial group, with Deltaproteobacteria dominating the sediment community, and these were affiliated with the order Desulfuromonadales. The archaeal phylotypes were all closely related to uncultivated species, and the majority of the members were related to the orders Methanosarcinales and Halobacteriales of the Euryarchaeota originating from methane hydrate bearing or alkaline sediments. The rest of the archaeal phylotypes belonged to the phylum Crenarchaeota, with representatives from similar habitats. These results suggested that a large number of novel microbial groups and potential methanogenesis may exist in this unique ecosystem.

  19. Hydrogen Isotopic Composition of Hornblendes From Active Volcanoes of Mexico

    NASA Astrophysics Data System (ADS)

    Taran, Y.; Kusakabe, M.; Valdez, G.; Mora, J. C.

    2002-12-01

    Horblendes (Hb) crystallize in water-rich magmas in magma chambers or in deeper zones. Isotopic composition of hydrogen in OH-groups of Hb represents the water isotopic composition of magmatic fluid or dissolved magmatic volatiles and therefore, is an isotopic characteristics of magmatic water. At lower vapor pressure in conduits and shallower magma chambers, Hb can decompose and loose water with significant isotopic effects. We measured hydrogen isotopic composition of hornblendes from modern lavas and pyroclastics of El Chichon, Colima and Popocatepetl volcanoes. Hornblendes from the last and previous pyroclastic flows of El Chichon are the more abundant mineral phases (after plagioclase), showing pleochroism from green to brown. They are relatively uniform in composition (close to magnesian hastingsite hornblende), without chemical variations between cores and rims. Using the Johnson and Rutherford (1989) calibration of the Al-in-hornblende geobarometer, the hornblendes show equilibrium with the melt at pressure of 4 kb that correspond to 12 km of depth. These pressure conditions likely represent the location of the magma chamber below El Chichon volcano, however, these pressure estimates need to be confirmed. The water content of all analyzed Hbs is 1.5-1.8 wt%, but may be higher due to a minor amount of impurities of pyroxenes which sometimes are difficult to separate from Hb. Hydrogen isotopic composition in 10 samples of Hb from El Chichon of different age and facies (pumice, lithic fragments in pyroclastics) was in a narrow range -40 to -37 permil V-SMOW. Such isotopic signature corresponds to so-called "andesitic" waters, i.e. waters from subduction-related magmas, The origin of these waters is suggested to be the recycled water from subducted oceanic sediments. The data for El Chichon volcano are in the range of the already known values for subduction-related magmas though the tectonic setting of El Chichon is more complicated. The measured isotopic

  20. Hydrogochemical tools for monitoring active volcanoes: Applications to El Chichón volcano, México.

    NASA Astrophysics Data System (ADS)

    Armienta, M. A.; de La Cruz-Reyna, S.; Ramos, S.; Morton, O.; Ceniceros, N.; Aguayo, A.; Cruz, O.

    2010-03-01

    In 1982, a series of eruptions resulted in the worst disaster linked with volcanic activity in México. The characteristics of the phenomena together with a lack of prevention measures resulted in approximately 2000 deaths. An important aspect to prevent disasters is a thorough knowledge and monitoring of the potentially destructive natural phenomena. Monitoring the activity of dormant or active volcanoes by various methods is thus a key measure to estimate the hazard and design adequate risk reduction measures. Despite of the 1982 volcanic disaster, until only a few years, hydrogeochemical monitoring was the only regular surveillance of El Chichón post-eruptive activity. The first samples of the crater-lake water were collected by Casadevall et al. in 1983. Since 1985, a systematic sampling and chemical analyses program has been carried out by the Geophysics Institute in collaboration with local authorities from the State of Chiapas. Chemical analyses of main ions and Rare Earth elements (REE) are performed in the Laboratorio de Química Analítica and Laboratorio ICP-MS of the Instituto de Geofísica, UNAM. Results are interpreted considering the physico-chemical changes that may be recognized as precursors of volcanic activity. The problem is difficult because at least two main water reservoirs feed the crater lake; besides, dissolution of acid volcanic gases, water-rock interactions and geochemical processes among dissolved species have resulted in a complex chemical behavior of the lake-water along the years. The calculated degree of neutralization, pH values, and chloride and sulfate concentrations of samples taken at different dates result in a classification of the volcano as active or inactive according to the method developed by Varekamp. A pH of 0.5, very high conductivity and a temperature of about 50°C characterized the first years following the eruptions. An overall decrease on the temperature and ionic concentrations, along with a less acid p

  1. From dome to dust: shallow crystallization and fragmentation of conduit magma during the 2004-2006 dome extrusion of Mount St. Helens, Washington: Chapter 19 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Cashman, Katharine V.; Thornber, Carl R.; Pallister, John S.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    Comparison of eruptive conditions during the 2004-6 activity at Mount St. Helens with those of other spine-forming eruptions suggests that magma ascent rates of about 10-4 m/s or less allow sufficient degassing and crystallization within the conduit to form large volcanic spines of intermediate composition (andesite to dacite). Solidification deep within the conduit, in turn, requires transport of the solid plug over long distances (hundreds of meters); resultant large strains are responsible for extensive brittle breakage and development of thick gouge zones. Moreover, similarities between gouge textures and those of ash emitted by explosions from spine margins indicate that fault gouge is the origin for the ash. As the comminution and generation of ash-sized particles was clearly a multistep process, this observation suggests that fragmentation preceded, rather than accompanied, these explosions.

  2. Petrology of the 2004-2006 Mount St. Helens lava dome -- implications for magmatic plumbing and eruption triggering: Chapter 30 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Pallister, John S.; Thornber, Carl R.; Cashman, Katharine V.; Clynne, Michael A.; Lowers, Heather; Mandeville, Charles W.; Brownfield, Isabelle K.; Meeker, Gregory P.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    The question of new versus residual magma has implications for the long-term eruptive behavior of Mount St. Helens, because arrival of a new batch of dacitic magma from the deep crust could herald the beginning of a new long-term cycle of eruptive activity. It is also important to our understanding of what triggered the eruption and its future course. Two hypotheses for triggering are considered: (1) top-down fracturing related to the shallow groundwater system and (2) an increase in reservoir pressure brought about by recent magmatic replenishment. With respect to the future course of the eruption, similarities between textures and character of eruption of the 2004-6 dome and the long-duration (greater than 100 years) pre-1980 summit dome, along with the low eruptive rate of the current eruption, suggest that the eruption could continue sluggishly or intermittently for years to come.

  3. Infrasound Monitoring of the Volcanic Activities of Japanese Volcanoes in Korea

    NASA Astrophysics Data System (ADS)

    Lee, H. I.; Che, I. Y.; Shin, J. S.

    2015-12-01

    Since 1999 when our first infrasound array station(CHNAR) has been installed at Cheolwon, Korea Institute of Geoscience and Mineral Resources(KIGAM) is continuously observing infrasound signals with an infrasound array network, named KIN(Korean Infrasound Network). This network is comprised of eight seismo-acoustic array stations(BRDAR, YPDAR, KMPAR, CHNAR, YAGAR, KSGAR, ULDAR, TJIAR). The aperture size of the smallest array is 300m and the largest is about 1.4km. The number of infrasound sensors are between 4(TJIAR) and 18(YAGAR), and 1~5 seismometers are collocated with infrasound sensors. Many interesting infrasound signals associated with different type of sources, such as blasting, large earthquake, bolide, volcanic explosion are detected by KIN in the past 15 years. We have analyzed the infrasound signals possibly associated with the japanese volcanic explosions with reference to volcanic activity report published by Japanese Meteorological Agency. Analysis results of many events, for example, Asama volcano explosion in 2004 and Shinmoe volcano in 2011, are well matched with the official report. In some cases, however, corresponding infrasound signals are not identified. By comparison of the infrasound signals from different volcanoes, we also found that the characteristics of signals are distinguishing. It may imply that the specific volcano has its own unique fingerprint in terms of infrasound signal. It might be investigated by long-term infrasound monitoring for a specific volcano as a ground truth generating repetitive infrasound signal.

  4. Temporal Variations of Magnetic Field Associated with Seismic Activity at Cerro Machin Volcano, Colombia

    NASA Astrophysics Data System (ADS)

    Londono, J. M.; Serna, J. P.; Guzman, J.

    2011-12-01

    A study of magnetic variations was carried out at Cerro Machin Volcano, Colombia for the period 2009 -2010, with two permanent magnetometers located at South and North of the central dome, separated about 2.5 km each other. After corrections, we found that there is no clear correlation between volcanic seismicity and temporal changes of magnetic field for each magnetometer station, if they are analyzed individually. On the contrary, when we calculated the residual Magnetic field (RMF), for each magnetometer, and then we made the subtraction between them, and plot it vs time, we found a clear correlation of changes in local magnetic field with the occurrence of volcanic seismicity (ML >1.6). We found a change in the RMF between 1584 nT and 1608 nT, each time that a volcano-tectonic earthquake occurred. The máximum lapse time between the previous change in RMF and the further occurrence of the earthquake is 24 days, with an average of 11 days. This pattern occurred more than 9 times during the studied period. Based on the results, we believed that the simple methodology proposed here, is a good tool for monitoring changes in seismicity associated with activity at Cerro Machín volcano. We suggest that the temporal changes of RMF at Cerro Machín Volcano, are associated with piezo-magnetic effects, due to changes in strain-stress inside the volcano, produced by the interaction between local faulting and magma movement.

  5. Semi-active engine mount design using auxiliary magneto-rheological fluid compliance chamber

    NASA Astrophysics Data System (ADS)

    Mansour, H.; Arzanpour, S.; Golnaraghi, M. F.; Parameswaran, A. M.

    2011-03-01

    Engine mounts are used in the automotive industry to isolate engine and chassis by reducing the noise and vibration imposed from one to the other. This paper describes modelling, simulation and design of a semi-active engine mount that is designed specifically to address the complicated vibration pattern of variable displacement engines (VDE). The ideal isolation for VDE requires the stiffness to be switchable upon cylinder activation/deactivation operating modes. In order to have a modular design, the same hydraulic engine mount components are maintained and a novel auxiliary magneto-rheological (MR) fluid chamber is developed and retrofitted inside the pumping chamber. The new compliance chamber is a controllable pressure regulator, which can effectively alter the dynamic performance of the mount. Switching between different modes happens by turning the electrical current to the MR chamber magnetic coil on and off. A model has been developed for the passive hydraulic mount and then it is extended to include the MR auxiliary chamber as well. A proof-of-concept prototype of the design has been fabricated which validates the mathematical model. The results demonstrate unique capability of the developed semi-active mount to be used for VDE application.

  6. Geologic map of Mount Gareloi, Gareloi Island, Alaska

    USGS Publications Warehouse

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

    2012-01-01

    As part of an effort to both monitor and study all historically active volcanoes in Alaska, the Alaska Volcano Observatory (AVO) undertook a field program at Mount Gareloi in the summer of 2003. During a month-long period, seismic networks were installed at Mount Gareloi and the neighboring Tanaga volcanic cluster. During this time, we undertook the first geologic field study of the volcano since Robert Coats visited Gareloi Island for four days in 1946. Understanding the geology of this relatively small island is important from a hazards perspective, because Mount Gareloi lies beneath a heavily trafficked air route between North America and Asia and has frequently erupted airborne ash since 1760. At least two landslides from the island have deposited debris on the sea floor; thus, landslide-generated tsunamis are also a potential hazard. Since seismic instruments were installed in 2003, they have detected small but consistent seismic signals from beneath Mount Gareloi's edifice, suggesting an active hydrothermal system. Mount Gareloi is also important from the standpoint of understanding subduction-related volcanism, because it lies in the western portion of the volcanically active arc, where subduction is oblique to the arc front. Understanding the compositional evolution of Mount Gareloi fills a spatial gap in along-arc studies.

  7. Methods of InSAR atmosphere correction for volcano activity monitoring

    USGS Publications Warehouse

    Gong, W.; Meyer, F.; Webley, P.W.; Lu, Zhiming

    2011-01-01

    When a Synthetic Aperture Radar (SAR) signal propagates through the atmosphere on its path to and from the sensor, it is inevitably affected by atmospheric effects. In particular, the applicability and accuracy of Interferometric SAR (InSAR) techniques for volcano monitoring is limited by atmospheric path delays. Therefore, atmospheric correction of interferograms is required to improve the performance of InSAR for detecting volcanic activity, especially in order to advance its ability to detect subtle pre-eruptive changes in deformation dynamics. In this paper, we focus on InSAR tropospheric mitigation methods and their performance in volcano deformation monitoring. Our study areas include Okmok volcano and Unimak Island located in the eastern Aleutians, AK. We explore two methods to mitigate atmospheric artifacts, namely the numerical weather model simulation and the atmospheric filtering using Persistent Scatterer processing. We investigate the capability of the proposed methods, and investigate their limitations and advantages when applied to determine volcanic processes. ?? 2011 IEEE.

  8. Translating Volcano Hazards Research in the Cascades Into Community Preparedness

    NASA Astrophysics Data System (ADS)

    Ewert, J. W.; Driedger, C. L.

    2015-12-01

    Research by the science community into volcanic histories and physical processes at Cascade volcanoes in the states of Washington, Oregon, and California has been ongoing for over a century. Eruptions in the 20th century at Lassen Peak and Mount St. Helen demonstrated the active nature of Cascade volcanoes; the 1980 eruption of Mount St. Helens was a defining moment in modern volcanology. The first modern volcano hazards assessments were produced by the USGS for some Cascade volcanoes in the 1960s. A rich scientific literature exists, much of which addresses hazards at these active volcanoes. That said community awareness, planning, and preparation for eruptions generally do not occur as a result of a hazard analyses published in scientific papers, but by direct communication with scientists. Relative to other natural hazards, volcanic eruptions (or large earthquakes, or tsunami) are outside common experience, and the public and many public officials are often surprised to learn of the impacts volcanic eruptions could have on their communities. In the 1980s, the USGS recognized that effective hazard communication and preparedness is a multi-faceted, long-term undertaking and began working with federal, state, and local stakeholders to build awareness and foster community action about volcano hazards. Activities included forming volcano-specific workgroups to develop coordination plans for volcano emergencies; a concerted public outreach campaign; curriculum development and teacher training; technical training for emergency managers and first responders; and development of hazard information that is accessible to non-specialists. Outcomes include broader ownership of volcano hazards as evidenced by bi-national exchanges of emergency managers, community planners, and first responders; development by stakeholders of websites focused on volcano hazards mitigation; and execution of table-top and functional exercises, including evacuation drills by local communities.

  9. Inside active volcanoes; an exhibit on the move!

    USGS Publications Warehouse

    Fiske, R.S.

    1990-01-01

    All of us are aware of the emphasis currently being placed in the United States on science education and public understanding of science. Most of this emphasis is directed toward mass audiences through book publications, school curricula, and television programs; sadly, most of it deals with non-earth science topics. In an effort to take advantage of this awakened consciousness and to highlight the earth sciences, the Smithsonian Institution and the U.S Geological Survey joined forces to prepare a traveling exhibit on volcanoes that is currently touring the country. This note will serve to bring you up to date on the progress of this exhibit as it reaches the mid-point of its tour. 

  10. Alaska volcanoes guidebook for teachers

    USGS Publications Warehouse

    Adleman, Jennifer N.

    2011-01-01

    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

  11. VEPP Exercise: Volcanic Activity and Monitoring of Pu`u `O`o, Kilauea Volcano, Hawaii

    NASA Astrophysics Data System (ADS)

    Rodriguez, L. A.

    2010-12-01

    A 10-week project will be tested during the Fall semester 2010, for a Volcanic Hazards elective course, for undergraduate Geology students of the University of Puerto Rico at Mayaguez. This exercise was developed during the Volcanoes Exploration Project: Pu`u `O`o (VEPP) Workshop, held on the Big Island of Hawaii in July 2010. For the exercise the students will form groups (of 2-4 students), and each group will be assigned a monitoring technique or method, among the following: seismic (RSAM data), deformation (GPS and tilt data), observations (webcam and lava flow maps), gas and thermal monitoring. The project is designed for Geology undergraduates who have a background in introductory geology, types of volcanoes and eruptions, magmatic processes, characteristics of lava flows, and other related topics. It is divided in seven tasks, starting with an introduction and demonstration of the VEPP website and the VALVE3 software, which is used to access monitoring data from the current eruption of Pu`u `O`o, Kilauea volcano, Hawaii. The students will also familiarize themselves with the history of Kilauea volcano and its current eruption. At least weekly the groups will acquire data (mostly near-real-time) from the different monitoring techniques, in the form of time series, maps, videos, and images, in order to identify trends in the data. The groups will meet biweekly in the computer laboratory to work together in the analysis and interpretation of the data, with the support of the instructor. They will give reports on the progress of the exercise, and will get feedback from the instructor and from the other expert groups. All groups of experts will relate their findings to the recent and current activity of Kilauea volcano, and the importance of their specific type of monitoring. The activity will culminate with a written report and an oral presentation. The last task of the project consists of a wrap-up volcano monitoring exercise, in which the students will

  12. Foot-mounted inertial measurement unit for activity classification.

    PubMed

    Ghobadi, Mostafa; Esfahani, Ehsan T

    2014-01-01

    This paper proposes a classification technique for daily base activity recognition for human monitoring during physical therapy in home. The proposed method estimates the foot motion using single inertial measurement unit, then segments the motion into steps classify them by template-matching as walking, stairs up or stairs down steps. The results show a high accuracy of activity recognition. Unlike previous works which are limited to activity recognition, the proposed approach is more qualitative by providing similarity index of any activity to its desired template which can be used to assess subjects improvement.

  13. Methanogenic activity and diversity in the centre of the Amsterdam Mud Volcano, Eastern Mediterranean Sea.

    PubMed

    Lazar, Cassandre Sara; John Parkes, R; Cragg, Barry A; L'Haridon, Stephane; Toffin, Laurent

    2012-07-01

    Marine mud volcanoes are geological structures emitting large amounts of methane from their active centres. The Amsterdam mud volcano (AMV), located in the Anaximander Mountains south of Turkey, is characterized by intense active methane seepage produced in part by methanogens. To date, information about the diversity or the metabolic pathways used by the methanogens in active centres of marine mud volcanoes is limited. (14)C-radiotracer measurements showed that methylamines/methanol, H(2)/CO(2) and acetate were used for methanogenesis in the AMV. Methylotrophic methanogenesis was measured all along the sediment core, Methanosarcinales affiliated sequences were detected using archaeal 16S PCR-DGGE and mcrA gene libraries, and enrichments of methanogens showed the presence of Methanococcoides in the shallow sediment layers. Overall acetoclastic methanogenesis was higher than hydrogenotrophic methanogenesis, which is unusual for cold seep sediments. Interestingly, acetate porewater concentrations were extremely high in the AMV sediments. This might be the result of organic matter cracking in deeper hotter sediment layers. Methane was also produced from hexadecanes. For the most part, the methanogenic community diversity was in accordance with the depth distribution of the H(2)/CO(2) and acetate methanogenesis. These results demonstrate the importance of methanogenic communities in the centres of marine mud volcanoes.

  14. Volcano Infrasound

    NASA Astrophysics Data System (ADS)

    Johnson, J. B.; Fee, D.; Matoza, R. S.

    2013-12-01

    Open-vent volcanoes generate prodigious low frequency sound waves that tend to peak in the infrasound (<20 Hz) band. These long wavelength (> ~20 m) atmospheric pressure waves often propagate long distances with low intrinsic attenuation and can be well recorded with a variety of low frequency sensitive microphones. Infrasound records may be used to remotely monitor eruptions, identify active vents or track gravity-driven flows, and/or characterize source processes. Such studies provide information vital for both scientific study and volcano monitoring efforts. This presentation proposes to summarize and standardize some of the terminology used in the still young, yet rapidly growing field of volcano infrasound. Herein we suggest classification of typical infrasound waveform types, which include bimodal pulses, blast (or N-) waves, and a variety of infrasonic tremors (including broadband, harmonic, and monotonic signals). We summarize various metrics, including reduced pressure, intensity, power, and energy, in which infrasound excess pressures are often quantified. We also describe the spectrum of source types and radiation patterns, which are typically responsible for recorded infrasound. Finally we summarize the variety of propagation paths that are common for volcano infrasound radiating to local (<10 km), regional (out to several hundred kilometers), and global distances. The effort to establish common terminology requires community feedback, but is now timely as volcano infrasound studies proliferate and infrasound becomes a standard component of volcano monitoring.

  15. A new robust adaptive controller for vibration control of active engine mount subjected to large uncertainties

    NASA Astrophysics Data System (ADS)

    Fakhari, Vahid; Choi, Seung-Bok; Cho, Chang-Hyun

    2015-04-01

    This work presents a new robust model reference adaptive control (MRAC) for vibration control caused from vehicle engine using an electromagnetic type of active engine mount. Vibration isolation performances of the active mount associated with the robust controller are evaluated in the presence of large uncertainties. As a first step, an active mount with linear solenoid actuator is prepared and its dynamic model is identified via experimental test. Subsequently, a new robust MRAC based on the gradient method with σ-modification is designed by selecting a proper reference model. In designing the robust adaptive control, structured (parametric) uncertainties in the stiffness of the passive part of the mount and in damping ratio of the active part of the mount are considered to investigate the robustness of the proposed controller. Experimental and simulation results are presented to evaluate performance focusing on the robustness behavior of the controller in the face of large uncertainties. The obtained results show that the proposed controller can sufficiently provide the robust vibration control performance even in the presence of large uncertainties showing an effective vibration isolation.

  16. Advanced semi-active engine and transmission mounts: tools for modelling, analysis, design, and tuning

    NASA Astrophysics Data System (ADS)

    Farjoud, Alireza; Taylor, Russell; Schumann, Eric; Schlangen, Timothy

    2014-02-01

    This paper is focused on modelling, design, and testing of semi-active magneto-rheological (MR) engine and transmission mounts used in the automotive industry. The purpose is to develop a complete analysis, synthesis, design, and tuning tool that reduces the need for expensive and time-consuming laboratory and field tests. A detailed mathematical model of such devices is developed using multi-physics modelling techniques for physical systems with various energy domains. The model includes all major features of an MR mount including fluid dynamics, fluid track, elastic components, decoupler, rate-dip, gas-charged chamber, MR fluid rheology, magnetic circuit, electronic driver, and control algorithm. Conventional passive hydraulic mounts can also be studied using the same mathematical model. The model is validated using standard experimental procedures. It is used for design and parametric study of mounts; effects of various geometric and material parameters on dynamic response of mounts can be studied. Additionally, this model can be used to test various control strategies to obtain best vibration isolation performance by tuning control parameters. Another benefit of this work is that nonlinear interactions between sub-components of the mount can be observed and investigated. This is not possible by using simplified linear models currently available.

  17. Volcanic gas emissions during active dome growth at Mount Cleveland, Alaska, August 2015

    NASA Astrophysics Data System (ADS)

    Werner, Cynthia; Kern, Christoph; Lyons, John; Kelly, Peter; Schneider, David; Wallace, Kristi; Wessels, Rick

    2016-04-01

    Volcanic gas emissions and chemistry data were measured for the first time at Mount Cleveland (1730 m) in the Central Aleutian arc, Alaska, on August 14-15, 2015 as part of the NSF-GeoPRISMS initiative, and co-funded by the Deep Carbon Observatory (DCO) and the USGS Alaska Volcano Observatory. The measurements were made in the month following two explosive events (July 21 and August 7, 2015) that destroyed a small dome (˜50x85 m), which had experienced episodic growth in the crater since November, 2014. These explosions resulted in the elevation of the aviation color code and alert level from Yellow/Advisory to Orange/Watch on July 21, 2015. Between the November, 2014 and July, 2015 dome-destroying explosions, the volcano experienced: (1) frequent periods of elevated surface temperatures in the summit region (based on Mid-IR satellite observations), (2) limited volcano-seismic tremor, (3) visible degassing as recorded in webcam images with occasionally robust plumes, and (4) at least one aseismic volcanic event that deposited small amounts of ash on the upper flanks of the volcano (detected by infrasound, observed visually and in Landsat 8 images). Intermittent plumes were also sometimes detectable up to 60 km downwind in Mid-IR satellite images, but this was not typical. Lava extrusion resumed following the explosion as indicated in satellite data by highly elevated Mid-IR surface temperatures, but was not identifiable in seismic data. By early-mid August, 2015, a new dome growing in the summit crater had reached 80 m across with temperatures of 550-600 C as measured on August 4 with a helicopter-borne thermal IR camera. A semitransparent plume extended several kilometers downwind of the volcano during the field campaign. A helicopter instrumented with an upward-looking UV spectrometer (mini DOAS) and a Multi-GAS was used to measure SO2 emission rates and in situ mixing ratios of H2O, CO2, SO2, and H2S in the plume. On August 14 and 15, 2015, a total of 14

  18. Eruptive history, current activity and risk estimation using geospatial information in the Colima volcano, Mexico

    NASA Astrophysics Data System (ADS)

    Suarez-Plascencia, C.; Camarena-Garcia, M.; Nunez-Cornu, F. J.; Flores-Peña, S.

    2013-12-01

    Colima volcano, also known as Volcan de Fuego (19 30.696 N, 103 37.026 W), is located on the border between the states of Jalisco and Colima, and is the most active volcano in Mexico. In January 20, 1913, Colima had its biggest explosion of the twentieth century, with VEI 4, after the volcano had been dormant for almost 40 years. In 1961, a dome reached the northeastern edge of the crater and started a new lava flow, and from this date maintains constant activity. In February 10, 1999, a new explosion occurred at the summit dome. The activity during the 2001-2005 period was the most intense, but did not exceed VEI 3. The activity resulted in the formation of domes and their destruction after explosive events. The explosions originated eruptive columns, reaching altitudes between 4,500 and 9,000 masl, further pyroclastic flows reaching distances up to 3.5 km from the crater. During the explosive events, ash emissions were generated in all directions reaching distances up to 100 km, slightly affecting the nearby villages: Tuxpan, Tonila, Zapotlan, Cuauhtemoc, Comala, Zapotitlan de Vadillo and Toliman. During 2005 to July 2013, this volcano has had an intense effusive-explosive activity; similar to the one that took place during the period of 1890 through 1905. That was before the Plinian eruption of 1913, where pyroclastic flows reached a distance of 15 km from the crater. In this paper we estimate the risk of Colima volcano through the analysis of the vulnerability variables, hazard and exposure, for which we use: satellite imagery, recurring Fenix helicopter over flights of the state government of Jalisco, the use of the images of Google Earth and the population census 2010 INEGI. With this information and data identified changes in economic activities, development, and use of land. The expansion of the agricultural frontier in the lower sides of the volcano Colima, and with the advancement of traditional crops of sugar cane and corn, increased the growth of

  19. Magma plumbing system and seismicity of an active mid-ocean ridge volcano.

    PubMed

    Schmid, Florian; Schlindwein, Vera; Koulakov, Ivan; Plötz, Aline; Scholz, John-Robert

    2017-02-20

    At mid-ocean ridges volcanism generally decreases with spreading rate but surprisingly massive volcanic centres occur at the slowest spreading ridges. These volcanoes can host unexpectedly strong earthquakes and vigorous, explosive submarine eruptions. Our understanding of the geodynamic processes forming these volcanic centres is still incomplete due to a lack of geophysical data and the difficulty to capture their rare phases of magmatic activity. We present a local earthquake tomographic image of the magma plumbing system beneath the Segment 8 volcano at the ultraslow-spreading Southwest Indian Ridge. The tomography shows a confined domain of partial melt under the volcano. We infer that from there melt is horizontally transported to a neighbouring ridge segment at 35 km distance where microearthquake swarms and intrusion tremor occur that suggest ongoing magmatic activity. Teleseismic earthquakes around the Segment 8 volcano, prior to our study, indicate that the current magmatic spreading episode may already have lasted over a decade and hence its temporal extent greatly exceeds the frequent short-lived spreading episodes at faster opening mid-ocean ridges.

  20. Magma plumbing system and seismicity of an active mid-ocean ridge volcano

    NASA Astrophysics Data System (ADS)

    Schmid, Florian; Schlindwein, Vera; Koulakov, Ivan; Plötz, Aline; Scholz, John-Robert

    2017-02-01

    At mid-ocean ridges volcanism generally decreases with spreading rate but surprisingly massive volcanic centres occur at the slowest spreading ridges. These volcanoes can host unexpectedly strong earthquakes and vigorous, explosive submarine eruptions. Our understanding of the geodynamic processes forming these volcanic centres is still incomplete due to a lack of geophysical data and the difficulty to capture their rare phases of magmatic activity. We present a local earthquake tomographic image of the magma plumbing system beneath the Segment 8 volcano at the ultraslow-spreading Southwest Indian Ridge. The tomography shows a confined domain of partial melt under the volcano. We infer that from there melt is horizontally transported to a neighbouring ridge segment at 35 km distance where microearthquake swarms and intrusion tremor occur that suggest ongoing magmatic activity. Teleseismic earthquakes around the Segment 8 volcano, prior to our study, indicate that the current magmatic spreading episode may already have lasted over a decade and hence its temporal extent greatly exceeds the frequent short-lived spreading episodes at faster opening mid-ocean ridges.

  1. Magma plumbing system and seismicity of an active mid-ocean ridge volcano

    PubMed Central

    Schmid, Florian; Schlindwein, Vera; Koulakov, Ivan; Plötz, Aline; Scholz, John-Robert

    2017-01-01

    At mid-ocean ridges volcanism generally decreases with spreading rate but surprisingly massive volcanic centres occur at the slowest spreading ridges. These volcanoes can host unexpectedly strong earthquakes and vigorous, explosive submarine eruptions. Our understanding of the geodynamic processes forming these volcanic centres is still incomplete due to a lack of geophysical data and the difficulty to capture their rare phases of magmatic activity. We present a local earthquake tomographic image of the magma plumbing system beneath the Segment 8 volcano at the ultraslow-spreading Southwest Indian Ridge. The tomography shows a confined domain of partial melt under the volcano. We infer that from there melt is horizontally transported to a neighbouring ridge segment at 35 km distance where microearthquake swarms and intrusion tremor occur that suggest ongoing magmatic activity. Teleseismic earthquakes around the Segment 8 volcano, prior to our study, indicate that the current magmatic spreading episode may already have lasted over a decade and hence its temporal extent greatly exceeds the frequent short-lived spreading episodes at faster opening mid-ocean ridges. PMID:28218270

  2. Investigation of Volcanic Seismo-Acoustic Signals: Applying Subspace Detection to Lava Fountain Activity at Etna Volcano

    NASA Astrophysics Data System (ADS)

    Sciotto, M.; Rowe, C. A.; Cannata, A.; Arrowsmith, S.; Privitera, E.; Gresta, S.

    2011-12-01

    The current eruption of Mount Etna, which began in January, 2011, has produced numerous energetic episodes of lava fountaining, which have bee recorded by the INGV seismic and acoustic sensors located on and around the volcano. The source of these events was the pit crater on the east flank of the Southeast crater of Etna. Simultaneously, small levels of activity were noted in the Bocca Nuova as well, prior to its lava fountaining activity. We will present an analysis of seismic and acoustic signals related to the 2011 activity wherein we apply the method of subspace detection to determine whether the source exhibits a temporal evolution within or between fountaining events, or otherwise produces repeating, classifiable events occurring through the continuous explosive degassing. We will examine not only the raw waveforms, but also spectral variations in time as well as time-varying statistical functions such as signal skewness and kurtosis. These results will be compared to straightforward cross-correlation analysis. In addition to classification performance, the subspace method has promise to outperform standard STA/LTA methods for real-time event detection in cases where similar events can be expected.

  3. Ages of calderas, large explosive craters and active volcanoes in the Kuril-Kamchatka region, Russia

    NASA Astrophysics Data System (ADS)

    Braitseva, O. A.; Melekestsev, I. V.; Ponomareva, V. V.; Sulerzhitsky, L. D.

    1995-12-01

    The ages of most of calderas, large explosive craters and active volcanoes in the Kuril-Kamchatka region have been determined by extensive geological, geomorphological, tephrochronological and isotopic geochronological studies, including more than 600 14C dates. Eight ‘Krakatoa-type’ and three ‘Hawaiian-type’ calderas and no less than three large explosive craters formed here during the Holocene. Most of the Late Pleistocene Krakatoa-type calderas were established around 30 000 40 000 years ago. The active volcanoes are geologically very young, with maximum ages of about 40 000 50 000 years. The overwhelming majority of recently active volcanic cones originated at the very end of the Late Pleistocene or in the Holocene. These studies show that all Holocene stratovolcanoes in Kamchatka were emplaced in the Holocene only in the Eastern volcanic belt. Periods of synchronous, intensified Holocene volcanic activity occurred within the time intervals of 7500 7800 and 1300 1800 14C years BP.

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

    USGS Publications Warehouse

    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

    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

  5. A Scientific Excursion: Volcanoes.

    ERIC Educational Resources Information Center

    Olds, Henry, Jr.

    1983-01-01

    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)

  6. Active Volcanoes of the Kurile Islands: A Reference Guide for Aviation Users

    USGS Publications Warehouse

    Neal, Christina A.; Rybin, Alexander; Chibisova, Marina; Miller, Edward

    2008-01-01

    Introduction: The many volcanoes of the remote and mostly uninhabited Kurile Island arc (fig. 1; table 1) pose a serious hazard for air traffic in the North Pacific. Ash clouds from Kurile eruptions can impact some of the busiest air travel routes in the world and drift quickly into airspace managed by three countries: Russia, Japan, and the United States. Prevailing westerly winds throughout the region will most commonly send ash from any Kurile eruption directly across the parallel North Pacific airways between North America and Asia (Kristine A. Nelson, National Weather Service, oral commun., 2006; fig. 1). This report presents maps showing locations of the 36 most active Kurile volcanoes plotted on Operational Navigational Charts published by the Defense Mapping Agency (map sheets ONC F-10, F-11, and E-10; figs. 1, 2, 3, 4). These maps are intended to assist aviation and other users in the identification of restless Kurile volcanoes. A regional map is followed by three subsections of the Kurile volcanic arc (North, Central, South). Volcanoes and selected primary geographic features are labeled. All maps contain schematic versions of the principal air routes and selected air navigational fixes in this region.

  7. 2008 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Neal, Christina A.; McGimsey, Robert G.; Dixon, James P.; Cameron, Cheryl E.; Nuzhdaev, Anton A.; Chibisova, Marina

    2011-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, and volcanic unrest or suspected unrest at seven separate volcanic centers in Alaska during 2008. Significant explosive eruptions at Okmok and Kasatochi Volcanoes in July and August dominated Observatory operations in the summer and autumn. AVO maintained 24-hour staffing at the Anchorage facility from July 12 through August 28. Minor eruptive activity continued at Veniaminof and Cleveland Volcanoes. Observed volcanic unrest at Cook Inlet's Redoubt Volcano presaged a significant eruption in the spring of 2009. AVO staff also participated in hazard communication regarding eruptions or unrest at nine volcanoes in Russia as part of a collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  8. 2007 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Neal, Christina A.; Dixon, James P.; Malik, Nataliya; Chibisova, Marina

    2011-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, and volcanic unrest at or near nine separate volcanic centers in Alaska during 2007. The year was highlighted by the eruption of Pavlof, one of Alaska's most frequently active volcanoes. Glaciated Fourpeaked Mountain, a volcano thought to have been inactive in the Holocene, produced a phreatic eruption in the autumn of 2006 and continued to emit copious amounts of steam and volcanic gas into 2007. Redoubt Volcano showed the first signs of the unrest that would unfold in 2008-09. AVO staff also participated in hazard communication and monitoring of multiple eruptions at seven volcanoes in Russia as part of its collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  9. Earthquake swarms on Mount Erebus, Antarctica

    NASA Astrophysics Data System (ADS)

    Kaminuma, Katsutada; Baba, Megumi; Ueki, Sadato

    1986-12-01

    Mount Erebus (3794 m), located on Ross Island in McMurdo Sound, is one of the few active volcanoes in Antartica. A high-sensitivity seismic network has been operated by Japanese and US parties on and around the Volcano since December, 1980. The results of these observations show two kinds of seismic activity on Ross Island: activity concentrated near the summit of Mount Erebus associated with Strombolian eruptions, and micro-earthquake activity spread through Mount Erebus and the surrounding area. Seismicity on Mount Erebus has been quite high, usually exceeding 20 volcanic earthquakes per day. They frequently occur in swarms with daily counts exceeding 100 events. Sixteen earthquake swarms with more than 250 events per day were recorded by the seismic network during the three year period 1982-1984, and three notable earthquake swarms out of the sixteen were recognized, in October, 1982 (named 82-C), March-April, 1984 (84-B) and July, 1984 (84-F). Swarms 84-B and 84-F have a large total number of earthquakes and large Ishimoto-Iida's "m"; hence these two swarms are presumed to constitute on one of the precursor phenomena to the new eruption, which took place on 13 September, 1984, and lasted a few months.

  10. Dueling Volcanoes: How Activity Levels At Kilauea Influence Eruptions At Mauna Loa

    NASA Astrophysics Data System (ADS)

    Trusdell, F.

    2011-12-01

    The eruption of Kilauea at Pu`u `O`o is approaching its 29th anniversary. During this time, Mauna Loa has slowly inflated following its most recent eruption in 1984. This is Mauna Loa's longest inter-eruptive interval observed in HVO's 100 years of operation. When will the next eruption of Mauna Loa take place? Is the next eruption of Mauna Loa tied to the current activity at Kilauea? Historically, eruptive periods at Kilauea and Mauna Loa volcanoes appear to be inversely correlated. In the past, when Mauna Loa was exceptionally active, Kilauea Volcano was in repose, recovery, or in sustained lava lake activity. Swanson and co-workers (this meeting) have noted that explosive activity on Kilauea, albeit sporadic, was interspersed between episodes of effusive activity. Specifically, Swanson and co-workers note as explosive the time periods between 300 B.C.E.-1000 C.E and 1500-1800 C.E. They also point to evidence for low magma supply to Kilauea during these periods and few flank eruptions. During the former explosive period, Mauna Loa was exceedingly active, covering approximately 37% of its surface or 1882 km2, an area larger than Kilauea. This period is also marked by summit activity at Mauna Loa sustained for 300 years. In the 1500-1800 C.E. period, Mauna Loa was conspicuously active with 29 eruptions covering an area of 446 km2. In the late 19th and early 20th century, Kilauea was dominated by nearly continuous lava-lake activity. Meanwhile Mauna Loa was frequently active from 1843 C.E. to 1919 C.E., with 24 eruptions for an average repose time of 3.5 years. I propose that eruptive activity at one volcano may affect eruptions at the other, due to factors that impact magma supply, volcanic plumbing, and flank motion. This hypothesis is predicated on the notion that when the rift zones of Kilauea, and in turn its mobile south flank, are active, Mauna Loa's tendency to erupt is diminished. Kilauea's rift zones help drive the south flank seaward, in turn, as Mauna

  11. Effects of volcanism on the glaciers of Mount St. Helens

    USGS Publications Warehouse

    Brugman, Melinda M.; Post, Austin

    1981-01-01

    The cataclysmic eruption of Mount St. Helens May 18, 1980, removed 2.9 km2 (about 0.13 km3) of glacier snow and ice including a large part of Shoestring, Forsyth, Wishbone, Ape, Nelson, and all of Loowit and Leschi Glaciers. Minor eruptions and bulging of the volcano from March 27 to May 17 shattered glaciers which were on the deforming rock and deposited ash on other glaciers. Thick ash layers persisted after the May 18 eruption through the summer on most of the remaining snow and ice, and protected winter snow from melting on Swift and Dryer Glaciers. Melting and recrystalization of snow and ice surviving on Mount St. Helens could cause and lubricate mudflows and generate outburst floods. Study of glaciers that remain on this active volcano may assist in recognizing potential hazards on other volcanoes and lead to new contributions to knowledge of the transient response of glaciers to changes in mass balance or geometry.

  12. 1996 volcanic activity in Alaska and Kamchatka: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Neal, Christina A.; McGimsey, Robert G.

    1997-01-01

    During 1996, the Alaska Volcano Observatory (AVO) responded to eruptive activity, anomalous seismicity, or suspected volcanic activity at 10 of the approximately 40 active volcanic centers in the state of Alaska. As part of a formal role in KVERT (the Kamchatkan Volcano Eruption Response Team), AVO staff also disseminated information about eruptions and other volcanic unrest at six volcanic centers on the Kamchatka Peninsula and in the Kurile Islands, Russia.

  13. Mount St. Helens Flyover

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) image of Mt. St. Helens volcano in Washington State was acquired on August 8, 2000 and covers an area of 37 by 51 km. Mount Saint Helens, a volcano in the Cascade Range of southwestern Washington that had been dormant since 1857, began to show signs of renewed activity in early 1980. On 18 May 1980, it erupted with such violence that the top of the mountain was blown off, spewing a cloud of ash and gases that rose to an altitude of 19 kilometers. The blast killed about 60 people and destroyed all life in an area of some 180 square kilometers (some 70 square miles), while a much larger area was covered with ash and debris. It continues to spit forth ash and steam intermittently. As a result of the eruption, the mountain's elevation decreased from 2,950 meters to 2,549 meters. The simulated fly-over was produced by draping ASTER visible and near infrared image data over a digital topography model, created from ASTER's 3-D stereo bands. The color was computer enhanced to create a 'natural' color image, where the vegetation appears green. The topography has been exaggerated 2 times to enhance the appearance of the relief. Landsat7 aquired an image of Mt. St. Helens on August 22, 1999. Image and animation courtesy NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.

  14. The Pleistocene eruptive history of Mount St. Helens, Washington, from 300,000 to 12,800 years before present: Chapter 28 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Clynne, Michael A.; Calvert, Andrew T.; Wolfe, Edward W.; Evarts, Russell C.; Fleck, Robert J.; Lanphere, Marvin A.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    Preliminary petrographic analysis of these older rocks suggests that the volcano’s magmatic system was simpler during the Ape Canyon stage than during subsequent stages and that the magmatic system has evolved from relatively simple to more complex as the volcano matured. Compositional cycles as envisioned by C.A. Hopson and W.G. Melson for the Spirit Lake stage probably did not occur during the Ape Canyon stage but developed later during the Cougar and Swift Creek stages.

  15. Instrumentation in remote and dangerous settings; examples using data from GPS “spider” deployments during the 2004-2005 eruption of Mount St. Helens, Washington: Chapter 16 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    LaHusen, Richard G.; Swinford, Kelly J.; Logan, Matthew; Lisowski, Michael; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    Self-contained, single-frequency GPS instruments fitted on lightweight stations suitable for helicopter-sling payloads became a critical part of volcano monitoring during the September 2004 unrest and subsequent eruption of Mount St. Helens. Known as “spiders” because of their spindly frames, the stations were slung into the crater 29 times from September 2004 to December 2005 when conditions at the volcano were too dangerous for crews to install conventional equipment. Data were transmitted in near-real time to the Cascades Volcano Observatory in Vancouver, Washington. Each fully equipped unit cost about $2,500 in materials and, if not destroyed by natural events, was retrieved and redeployed as needed. The GPS spiders have been used to track the growth and decay of extruding dacite lava (meters per day), thickening and accelerated flow of Crater Glacier (meters per month), and movement of the 1980-86 dome from pressure and relaxation of the newly extruding lava dome (centimeters per day).

  16. Rapid response of a hydrologic system to volcanic activity: Masaya volcano, Nicaragua

    USGS Publications Warehouse

    Pearson, S.C.P.; Connor, C.B.; Sanford, W.E.

    2008-01-01

    Hydrologic systems change in response to volcanic activity, and in turn may be sensitive indicators of volcanic activity. Here we investigate the coupled nature of magmatic and hydrologic systems using continuous multichannel time series of soil temperature collected on the flanks of Masaya volcano, Nicaragua, one of the most active volcanoes in Central America. The soil temperatures were measured in a low-temperature fumarole field located 3.5 km down the flanks of the volcano. Analysis of these time series reveals that they respond extremely rapidly, on a time scale of minutes, to changes in volcanic activity also manifested at the summit vent. These rapid temperature changes are caused by increased flow of water vapor through flank fumaroles during volcanism. The soil temperature response, ~5 °C, is repetitive and complex, with as many as 13 pulses during a single volcanic episode. Analysis of the frequency spectrum of these temperature time series shows that these anomalies are characterized by broad frequency content during volcanic activity. They are thus easily distinguished from seasonal trends, diurnal variations, or individual rainfall events, which triggered rapid transient increases in temperature during 5% of events. We suggest that the mechanism responsible for the distinctive temperature signals is rapid change in pore pressure in response to magmatism, a response that can be enhanced by meteoric water infiltration. Monitoring of distal fumaroles can therefore provide insight into coupled volcanic-hydrologic-meteorologic systems, and has potential as an inexpensive monitoring tool.

  17. Geothermal activity and energy of the Yakedake volcano, Gifu-Nagano, Japan

    SciTech Connect

    Iriyama, Jun

    1996-12-31

    The temperature of the most active solfatara in the summit crater of the Yakedake volcano (altitude 2,455 m Gifu-Nagano, Japan) was 92.2 and 129.4{degrees}C in September 1995 and in October 1994, respectively. The temperature of solfatara in the northern summit dome at an altitude of 2,240 to 2,270 m ranged from 68.2 to 92.5{degrees}C in September 1995. The water sample from a crater pond, Shoga-ike, located on the summit, showed a pH and electrical conductivity of 4.38 and 42.2 {mu}S/cm in October 1991, 4.35 and 42.4 {mu}S/cm in September 1992, 4.11 and 76.6 {mu}S/cm in October 1994, and 4.30 and 45.1 {mu}S/cm in September 1995, respectively. In 1960, the water sample from the same pond showed the pH and electrical conductivity of 3.7 and 80.8 {mu}S/cm, respectively. Although the values of pH and electrical conductivity in 1994 approached to the values at the volcano`s pre-eruption in 1960, the eruption in the summit dome did not occur in 1995. However, a large steam explosion occurred in the Nakanoyu area of the southeastern Mountainside of the volcano. The geothermal energy within the summit dome at an altitude of 2,050 to 2,455 m of the Yakedake volcano is calculated, using new data, to be about 4.8 x 10{sup 17} J, which represents a thermal power output of 5.1 x 10{sup 2} MW{sub th} averaged over 30 yrs.

  18. Laboratory simulation of volcano seismicity.

    PubMed

    Benson, Philip M; Vinciguerra, Sergio; Meredith, Philip G; Young, R Paul

    2008-10-10

    The physical processes generating seismicity within volcanic edifices are highly complex and not fully understood. We report results from a laboratory experiment in which basalt from Mount Etna volcano (Italy) was deformed and fractured. The experiment was monitored with an array of transducers around the sample to permit full-waveform capture, location, and analysis of microseismic events. Rapid post-failure decompression of the water-filled pore volume and damage zone triggered many low-frequency events, analogous to volcanic long-period seismicity. The low frequencies were associated with pore fluid decompression and were located in the damage zone in the fractured sample; these events exhibited a weak component of shear (double-couple) slip, consistent with fluid-driven events occurring beneath active volcanoes.

  19. The Activity Of The Colima Volcano From 1999 To The 2003

    NASA Astrophysics Data System (ADS)

    Suarez-Plascencia, C.; Nuñez-Cornu, F.; Reyes-Davila, G.; Diaz-Torres, J.

    2004-12-01

    The Colima Volcano has shown intense activity since the 10th of February 1999. This explosive activity of 1999 and 2000 generated an elliptical crater of 260 x 265 m, which began to be filled in by a Dome from October 2001, at February 2002 the volume of the Dome was of approximately 2x106 m3 spreading over the edges of the crater and starting to flow during the following 11 months, in this period small lobes formed on the flanks of the volcano. Constants landslides originated in these lobes filled ravines of San Antonio, El Cordovan, El Muerto, El Cafesito and Atenquique (subsequent to the earthquake of January of the 2003) with non consolidated materials, increasing the hazard of lahares during the rainy season. Beginning February 2003 the explosive activity increased, most significantly from April to August, when the plumes reached heights over 2000 meters above the crater, occasionally small pyroclastic flows were observed. The explosive events continue to date. We mapped the most significant morphological changes produced at the summit by the activity described, using three photogrammetric flights conducted by INEGI (2003) and CARTODATA (2002 and 2003). These were data complemented by a very large number of photographs taken on helicopter flights undertaken during these months. Both the photographs and the digital mapping have provided detailed information to quantify the geomorphologic evolution of the superior section of the volcano, in the course of the last five years.

  20. Analysis of the seismicity activity of the volcano Ceboruco, Nayarit, Mexico

    NASA Astrophysics Data System (ADS)

    Rodriguez-Ayala, N. A.; Nunez-Cornu, F. J.; Escudero, C. R.; Zamora-Camacho, A.; Gomez, A.

    2014-12-01

    The Ceboruco is a stratovolcano is located in the state of Nayarit,Mexico (104 ° 30'31 .25 "W, 21 ° 7'28 .35" N, 2280msnm). This is an volcano active, as part of the Trans-Mexican Volcanic Belt, Nelson (1986) reports that it has had activity during the last 1000 years has averaged eruptions every 125 years or so, having last erupted in 1870, currently has fumarolic activity. In the past 20 years there has been an increase in the population and socio-economic activities around the volcano (Suárez Plascencia, 2013); which reason the Ceboruco study has become a necessity in several ways. Recent investigations of seismicity (Rodríguez Uribe et al., 2013) have classified the earthquakes in four families Ceboruco considering the waveform and spectral features. We present analysis included 57 days of seismicity from March to October 2012, in the period we located 97 events with arrivals of P and S waves clear, registered in at least three seasons, three components of the temporal network Ceboruco volcano.

  1. Seismicity at Uturuncu Volcano, Bolivia: Volcano-Tectonic Earthquake Swarms Triggered by the 2010 Maule, Chile Earthquake and Non-Triggered Background Activity

    NASA Astrophysics Data System (ADS)

    Christensen, D. H.; Chartrand, Z. A.; Jay, J.; Pritchard, M. E.; West, M. E.; McNutt, S. R.

    2010-12-01

    We find that the 270 ky dormant Uturuncu Volcano in SW Bolivia exhibits relatively high rates of shallow, volcano-tectonic seismicity that is dominated by swarm-like activity. We also document that the 27 February 2010 Mw 8.8 Maule, Chile earthquake triggered an exceptionally high rate of seismicity in the seconds to days following the main event. Although dormant, Uturuncu is currently being studied due to its large-scale deformation rate of 1-2 cm/yr uplift as revealed by InSAR. As part of the NASA-funded Andivolc project to investigate seismicity of volcanoes in the central Andes, a seismic network of 15 stations (9 Mark Products L22 short period and 6 Guralp CMG40T intermediate period sensors) with an average spacing of about 10 km was installed at Uturuncu from April 2009 to April 2010. Volcano-tectonic earthquakes occur at an average rate of about 3-4 per day, and swarms of 5-60 events within a span of minutes to hours occur a few times per month. Most of these earthquakes are located close to the summit at depths near and above sea level. The largest swarm occurred on 28 September 2009 and consisted of 60 locatable events over a time span of 28 hours. The locations of volcano-tectonic earthquakes at Uturuncu are oriented in a NW-SE trend, which matches the dominant orientation of regional faults and suggests a relationship between the fault system at Uturuncu and the regional tectonics of the area; a NW-SE trending fault beneath Uturuncu may serve to localize stresses that are accumulating over the broad area of uplift. Based on automated locations, the maximum local magnitude of these events is approximately M = 4 and the average magnitude is approximately M = 2. An initial estimate of the b-value is about b = 1.2. The Mw 8.8 Maule earthquake on 27 February 2010 triggered hundreds of local volcano-tectonic events at Uturuncu. High-pass filtering of the long period surface waves reveals that the first triggered events occurred with the onset of the Rayleigh

  2. Long-term explosive degassing and debris flow activity at West Mata submarine volcano

    NASA Astrophysics Data System (ADS)

    Dziak, R. P.; Bohnenstiehl, D. R.; Baker, E. T.; Matsumoto, H.; Caplan-Auerbach, J.; Embley, R. W.; Merle, S. G.; Walker, S. L.; Lau, T.-K.; Chadwick, W. W.

    2015-03-01

    West Mata is a 1200 m deep submarine volcano where explosive boninite eruptions were observed in 2009. The acoustic signatures from the volcano's summit eruptive vents Hades and Prometheus were recorded with an in situ (~25 m range) hydrophone during ROV dives in May 2009 and with local (~5 km range) moored hydrophones between December 2009 and August 2011. The sensors recorded low frequency (1-40 Hz), short duration explosions consistent with magma bubble bursts from Hades, and broadband, 1-5 min duration signals associated with episodes of fragmentation degassing from Prometheus. Long-term eruptive degassing signals, recorded through May 2010, preceded a several month period of declining activity. Degassing episodes were not recorded acoustically after early 2011, although quieter effusive eruption activity may have continued. Synchronous optical measurements of turbidity made between December 2009 and April 2010 indicate that turbidity maxima resulted from occasional south flank slope failures triggered by the collapse of accumulated debris during eruption intervals.

  3. Seismic activity related to the degassing of the Gorely volcano (Kamchatka)

    NASA Astrophysics Data System (ADS)

    Abramenkov, S. S.; Shapiro, N.; Koulakov, I.; Abkadyirov, I.; Frank, W.; Jakovlev, A.

    2015-12-01

    We analyzed continuous seismic records from a temporary network of 21 broadband seismograph that we installed in Gorely volcano (Kamchatka, Russia) between August 2013 and August 2014. During the studied period, the activity of Gorely was characterized by a sustained gas emission. We developed a source scanning algorithm based on summation of seismogram envelopes to automatically detect seismic events characterized by emerging signals without clear arrivals of P or S waves. With the help of this method, we detected and located numerous events originated from the vicinity of the main crater and caused by the volcano degassing. We then studied variations in spatio-temporal distribution of this seismic emission to characterize the evolution of the volcanic activity.

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

    NASA Astrophysics Data System (ADS)

    Stern, Robert J.; Bibee, L. D.

    1984-05-01

    Esmeralda Bank is the southernmost active volcano in the Izu-Volcano-Mariana Arc. This submarine volcano is one of the most active vents in the western Pacific. It has a total volume of about 27 km3, rising to within 30 m of sea level. Two dredge hauls from Esmeralda recovered fresh, nearly aphyric, vesicular basalts and basaltic andesites and minor basaltic vitrophyre. These samples reflect uniform yet unusual major and trace element chemistries. Mean abundances of TiO2 (1.3%) and FeO* (12.6%) are higher and CaO (9.2%) and Al2O3 (15.1%) are lower than rocks of similar silica content from other active Mariana Arc volcanoes. Mean incompatible element ratios K/Rb (488) and K/Ba (29) of Esmeralda rocks are indistinguishable from those of other Mariana Arc volcanoes. On a Ti-Zr plot, Esmeralda samples plot in the field of oceanic basalts while other Mariana Arc volcanic rocks plot in the field for island arcs. Incompatible element ratios K/Rb and K/Ba and isotopic compositions of Sr (87Sr/86Sr=0.70342 0.70348), Nd (ɛND=+7.6 to +8.1), and O(δ18O=+5.8 to +5.9) are incompatible with models calling for the Esmeralda source to include appreciable contributions from pelagic sediments or fresh or altered abyssal tholeiite from subduction zone melting. Instead, incompatible element and isotopic ratios of Esmeralda rocks are similar to those of intra-plate oceanic islands or “hot-spot” volcanoes in general and Kilauean tholeiites in particular. The conclusion that the source for Esmeralda lavas is an ocean-island type mantle reservoir is preferred. Esmeralda Bank rare earth element patterns are inconsistent with models calling for residual garnet in the source region, but are adequately modelled by 7 10% equilibrium partial melting of spinel lherzolite. This is supported by consideration of the results of melting experiments at 20 kbars, 1,150° C with CO2 and H2O as important volatile components. These experiments further indicate that low MgO (4.1%), MgO/FeO*(0.25) and

  5. Shrimp Populations on Northwest Rota, an Active Volcano of the Mariana Volcanic Arc

    NASA Astrophysics Data System (ADS)

    Tunnicliffe, V.; Juniper, S. K.; Limén, H.; Jones, W. J.; Vrijenhoek, R.; Webber, R.; Eerkes-Medrano, D.

    2004-12-01

    NW Rota-1 is a submarine volcano that manifested active volcanic and hydrothermal activity during submersible surveys in March 2004 (see Embley et al.). Substratum on the volcano summit (520 m depth) was entirely basalt outcrop or variously-sized ejecta lying near the angle of repose. While no fauna inhabited the rim of the volcanic pit, patches of shrimp were located within 25 m and on the nearby summit. Two species are present. Opaepele cf. loihi shows few morphological differences from either a nearby population on Eifuku Volcano (see Chadwick et al.) at 1700 m depth or from the type locality in Hawaii. A molecular comparison of COI sequences of 13 specimens found little difference from two Hawaiian sequences. Video observations detail frequent feeding activity using spatulate chelipeds to trim microbial filaments as the cephalothorax sways across the substratum. The second species is an undescribed Alvinocaris. Juveniles of this species appear to form clusters distinct from Opaepele where they also graze on filaments. Sparse adults of Alvinocaris range up to 5.5 cm long and display aggressive behaviour moving through patches of smaller shrimp. Densities of Opaepele were highest on sloping rock walls (over 500 per sq.m.) whereas adult Alvinocaris were more abundant on rubble. This division may reflect food preference: microbial filaments versus polychaetes and meiofauna. Characterization of particulates from these substrata was conducted using visual sorting and stable isotope composition. As Alvinocaris matures, the chelipeds enlarge, enabling a greater predatory capacity. Measurements of Opaepele from digital in situ images reveal a population structure suggesting a recent recruitment. Average size is significantly smaller than the Eifuku population and no egg-bearing females were collected. The disjunct range of this species where it occurs on active volcanoes 6000 km apart is puzzling. Further work on intermediate sites and into the reproductive strategy of

  6. Cellular immune responses and phagocytic activity of fishes exposed to pollution of volcano mud.

    PubMed

    Risjani, Yenny; Yunianta; Couteau, Jerome; Minier, Christophe

    2014-05-01

    Since May 29, 2006, a mud volcano in the Brantas Delta of the Sidoarjo district has emitted mud that has inundated nearby villages. Pollution in this area has been implicated in detrimental effects on fish health. In fishes, leukocyte and phagocytic cells play a vital role in body defenses. We report for the first time the effect of "LUSI" volcano mud on the immune systems of fish in the Brantas Delta. The aim of this study was to find biomarkers to allow the evaluation of the effects of volcanic mud and anthropogenic pollution on fish health in the Brantas Delta. The study took places at the Brantas Delta, which was polluted by volcano mud, and at reference sites in Karangkates and Pasuruan. Leukocyte numbers were determined using a Neubauer hemocytometer and a light microscope. Differential leukocyte counts were determined using blood smears stained with May Grunwald-Giemsa, providing neutrophil, lymphocyte and monocyte counts. Macrophages were taken from fish kidney, and their phagocytic activity was measured. In vitro analyses revealed that leukocyte and differential leukocyte counts (DLC) were higher in Channa striata and Chanos chanos caught from the polluted area. Macrophage numbers were higher in Oreochromis mossambicus than in the other species, indicating that this species is more sensitive to pollution. In areas close to volcanic mud eruption, all specimens had lower phagocytic activity. Our results show that immune cells were changed and phagocytic activity was reduced in the polluted area indicating cytotoxicity and alteration of the innate immune system in fishes exposed to LUSI volcano mud and anthropogenic pollution.

  7. Use of digital aerophotogrammetry to determine rates of lava dome growth, Mount St. Helens, Washington, 2004-2005: Chapter 8 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Schilling, Steve P.; Thompson, Ren A.; Messerich, James A.; Iwatsubo, Eugene Y.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    Successful application of aerophotogrammetry was possible during the critical earliest parts of the eruption because we had baseline data and photogrammetric infrastructure in place before the eruption began. The vertical aerial photographs, including the DEMs and calculations derived from them, were one of the most widely used data sets collected during the 2004-5 eruption, as evidenced in numerous contributions to this volume. These data were used to construct photogeologic maps, deformation vector fields, and profiles of the evolving dome and glacier. Extruded volumes and rates proved to be critical parameters to constrain models and hypotheses of eruption dynamics and thus helped to assess volcano hazards.

  8. Trace element and Pb isotope composition of plagioclase from dome samples from the 2004-2005 eruption of Mount St. Helens, Washington: Chapter 35 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Kent, Adam J.R.; Rowe, Michael C.; Thornber, Carl R.; Pallister, John S.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    Plagioclase crystals from gabbronorite inclusions in three dacite samples have markedly different trace-element and Pbisotope compositions from those of plagioclase phenocrysts, despite having a similar range of anorthite contents. Inclusions show some systematic differences from each other but typically have higher Ti, Ba, LREE, and Pb and lower Sr and have lower 208Pb/206Pb and 207Pb/206Pb ratios than coexisting plagioclase phenocrysts. The compositions of plagioclase from inclusions cannot be related to phenocryst compositions by any reasonable petrologic model. From this we suggest that they are unlikely to represent magmatic cumulates or restite inclusions but instead are samples of mafic Tertiary basement from beneath the volcano.

  9. Ground survey of active Central American volcanoes in November - December 1973

    NASA Technical Reports Server (NTRS)

    Stoiber, R. E. (Principal Investigator); Rose, W. I., Jr.

    1974-01-01

    The author has identified the following significant results. Thermal anomalies at two volcanoes, Santiaguito and Izalco, have grown in size in the past six months, based on repeated ground survey. Thermal anomalies at Pacaya volcano have became less intense in the same period. Large (500 m diameter) thermal anomalies exist at 3 volcanoes presently, and smaller scale anomalies are found at nine other volcanoes.

  10. Applications of geophysical methods to volcano monitoring

    USGS Publications Warehouse

    Wynn, Jeff; Dzurisin, Daniel; Finn, Carol A.; Kauahikaua, James P.; Lahusen, Richard G.

    2006-01-01

    The array of geophysical technologies used in volcano hazards studies - some developed originally only for volcano monitoring - ranges from satellite remote sensing including InSAR to leveling and EDM surveys, campaign and telemetered GPS networks, electronic tiltmeters and strainmeters, airborne magnetic and electromagnetic surveys, short-period and broadband seismic monitoring, even microphones tuned for infrasound. They include virtually every method used in resource exploration except large-scale seismic reflection. By “geophysical ” we include both active and passive methods as well as geodetic technologies. Volcano monitoring incorporates telemetry to handle high-bandwith cameras and broadband seismometers. Critical geophysical targets include the flux of magma in shallow reservoir and lava-tube systems, changes in active hydrothermal systems, volcanic edifice stability, and lahars. Since the eruption of Mount St. Helens in Washington State in 1980, and the eruption at Pu’u O’o in Hawai’i beginning in 1983 and still continuing, dramatic advances have occurred in monitoring technology such as “crisis GIS” and lahar modeling, InSAR interferograms, as well as gas emission geochemistry sampling, and hazards mapping and eruption predictions. The on-going eruption of Mount St. Helens has led to new monitoring technologies, including advances in broadband Wi-Fi and satellite telemetry as well as new instrumentation. Assessment of the gap between adequate monitoring and threat at the 169 potentially dangerous Holocene volcanoes shows where populations are dangerously exposed to volcanic catastrophes in the United States and its territories . This paper focuses primarily on Hawai’ian volcanoes and the northern Pacific and Cascades volcanoes. The US Geological Survey, the US National Park System, and the University of Utah cooperate in a program to monitor the huge Yellowstone volcanic system, and a separate observatory monitors the restive Long Valley

  11. Capturing the fingerprint of Etna volcano activity in gravity and satellite radar data.

    PubMed

    Del Negro, Ciro; Currenti, Gilda; Solaro, Giuseppe; Greco, Filippo; Pepe, Antonio; Napoli, Rosalba; Pepe, Susi; Casu, Francesco; Sansosti, Eugenio

    2013-10-30

    Long-term and high temporal resolution gravity and deformation data move us toward a better understanding of the behavior of Mt Etna during the June 1995 - December 2011 period in which the volcano exhibited magma charging phases, flank eruptions and summit crater activity. Monthly repeated gravity measurements were coupled with deformation time series using the Differential Synthetic Aperture Radar Interferometry (DInSAR) technique on two sequences of interferograms from ERS/ENVISAT and COSMO-SkyMed satellites. Combining spatiotemporal gravity and DInSAR observations provides the signature of three underlying processes at Etna: (i) magma accumulation in intermediate storage zones, (ii) magmatic intrusions at shallow depth in the South Rift area, and (iii) the seaward sliding of the volcano's eastern flank. Here we demonstrate the strength of the complementary gravity and DInSAR analysis in discerning among different processes and, thus, in detecting deep magma uprising in months to years before the onset of a new Etna eruption.

  12. Alaska Volcano Observatory

    USGS Publications Warehouse

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

    2008-01-01

    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.

  13. Review of eruptive activity at Tianchi volcano, Changbaishan, northeast China: implications for possible future eruptions

    NASA Astrophysics Data System (ADS)

    Wei, Haiquan; Liu, Guoming; Gill, James

    2013-04-01

    One of the largest explosive eruptions in the past several thousand years occurred at Tianchi volcano, also known as Changbaishan, on the China-North Korea border. This historically active polygenetic central volcano consists of three parts: a lower basaltic shield, an upper trachytic composite cone, and young comendite ash flows. The Millennium Eruption occurred between 938 and 946 ad, and was preceded by two smaller and chemically different rhyolitic pumice deposits. There has been at least one additional, small eruption in the last three centuries. From 2002 to 2005, seismicity, deformation, and the helium and hydrogen gas contents of spring waters all increased markedly, causing regional concern. We attribute this event to magma recharge or volatile exhalation or both at depth, followed by two episodes of addition of magmatic fluids into the overlying aquifer without a phreatic eruption. The estimated present magma accumulation rate is too low by itself to account for the 2002-2005 unrest. The most serious volcanic hazards are ash eruption and flows, and lahars. The available geological information and volcano monitoring data provide a baseline for comprehensive assessment of future episodes of unrest and possible eruptive activity.

  14. Passive vs. active degassing modes at an open-vent volcano (Stromboli, Italy)

    NASA Astrophysics Data System (ADS)

    Tamburello, G.; Aiuppa, A.; Kantzas, E. P.; McGonigle, A. J. S.; Ripepe, M.

    2012-12-01

    We report here on a UV-camera based field experiment performed on Stromboli volcano during 7 days in 2010 and 2011, aimed at obtaining the very first simultaneous assessment of all the different forms (passive and active) of SO2 release from an open-vent volcano. Using the unprecedented spatial and temporal resolution of the UV camera, we obtained a 0.8 Hz record of the total SO2 flux from Stromboli over a timeframe of ∼14 h, which ranged between 0.4 and 1.9 kg s-1 around a mean value of 0.7 kg s-1 and we concurrently derived SO2 masses for more than 130 Strombolian explosions and 50 gas puffs. From this, we show erupted SO2 masses have a variability of up to one order of magnitude, and range between 2 and 55 kg (average ∼20 kg), corresponding to a time integrated flux of 0.05±0.01 kg s-1. Our experimental constraints on individual gas puff mass (0.03-0.42 kg of SO2, averaging 0.19 kg) are the first of their kind, equating to an emission rate ranging from 0.02 to 0.27 kg s-1. On this basis, we conclude that puffing is two times more efficient than Strombolian explosions in the magmatic degassing process, and that active degassing (explosions+puffing) accounts for ∼23% (ranging from 10% to 45%) of the volcano's total SO2 flux, e.g., passive degassing between the explosions contributes the majority (∼77%) of the released gas. We furthermore integrate our UV camera gas data for the explosions and puffs, with independent geophysical data (infrared radiometer data and very long period seismicity), to offer key and novel insights into the degassing dynamics within the shallow conduit systems of this open-vent volcano.

  15. The Pacific Northwest; linkage between earthquake and volcano hazards

    USGS Publications Warehouse

    Crosson, R.S.

    1990-01-01

    The Pacific Northwest (Oregon, Washington, and northern California) is experiencing rapid industrial and population growth. The same conditions that make the region attractive- close proximity to both mountains and oceans, volcanoes and spectacular inland waters- also present significant geologic hazards that are easily overlooked in the normal timetable of human activities. The catastrophic eruption of Mount St. Helens 10 years ago serves as a dramatic reminder of the forces of nature that can be unleashed through volcanism. other volcanoes such as  mount Rainier, a majestic symbol of Washington, or Mount hood in Oregon, lie closer to population centers and could present far greater hazards should they become active. Earthquakes may affect even larger regions, prodcuging more cumulative damage. 

  16. Estimating eruption temperature from thermal emission spectra of lava fountain activity in the Erta'Ale (Ethiopia) volcano lava lake: Implications for observing Io's volcanoes

    USGS Publications Warehouse

    Davies, A.G.; Keszthelyi, L.; McEwen, A.S.

    2011-01-01

    We have analysed high-spatial-resolution and high-temporal-resolution temperature measurements of the active lava lake at Erta'Ale volcano, Ethiopia, to derive requirements for measuring eruption temperatures at Io's volcanoes. Lava lakes are particularly attractive targets because they are persistent in activity and large, often with ongoing lava fountain activity that exposes lava at near-eruption temperature. Using infrared thermography, we find that extracting useful temperature estimates from remote-sensing data requires (a) high spatial resolution to isolate lava fountains from adjacent cooler lava and (b) rapid acquisition of multi-color data. Because existing spacecraft data of Io's volcanoes do not meet these criteria, it is particularly important to design future instruments so that they will be able to collect such data. Near-simultaneous data at more than two relatively short wavelengths (shorter than 1 ??m) are needed to constrain eruption temperatures. Resolving parts of the lava lake or fountains that are near the eruption temperature is also essential, and we provide a rough estimate of the required image scale. ?? 2011 by the American Geophysical Union.

  17. Estimating eruption temperature from thermal emission spectra of lava fountain activity in the Erta'Ale (Ethiopia) volcano lava lake: Implications for observing Io's volcanoes

    USGS Publications Warehouse

    Davies, Ashley G.; Keszthelyi, Laszlo P.; McEwen, Alfred S.

    2011-01-01

    We have analysed high-spatial-resolution and high-temporal-resolution temperature measurements of the active lava lake at Erta'Ale volcano, Ethiopia, to derive requirements for measuring eruption temperatures at Io's volcanoes. Lava lakes are particularly attractive targets because they are persistent in activity and large, often with ongoing lava fountain activity that exposes lava at near-eruption temperature. Using infrared thermography, we find that extracting useful temperature estimates from remote-sensing data requires (a) high spatial resolution to isolate lava fountains from adjacent cooler lava and (b) rapid acquisition of multi-color data. Because existing spacecraft data of Io's volcanoes do not meet these criteria, it is particularly important to design future instruments so that they will be able to collect such data. Near-simultaneous data at more than two relatively short wavelengths (shorter than 1 μm) are needed to constrain eruption temperatures. Resolving parts of the lava lake or fountains that are near the eruption temperature is also essential, and we provide a rough estimate of the required image scale.

  18. Head-mounted active noise control system with virtual sensing technique

    NASA Astrophysics Data System (ADS)

    Miyazaki, Nobuhiro; Kajikawa, Yoshinobu

    2015-03-01

    In this paper, we apply a virtual sensing technique to a head-mounted active noise control (ANC) system we have already proposed. The proposed ANC system can reduce narrowband noise while improving the noise reduction ability at the desired locations. A head-mounted ANC system based on an adaptive feedback structure can reduce noise with periodicity or narrowband components. However, since quiet zones are formed only at the locations of error microphones, an adequate noise reduction cannot be achieved at the locations where error microphones cannot be placed such as near the eardrums. A solution to this problem is to apply a virtual sensing technique. A virtual sensing ANC system can achieve higher noise reduction at the desired locations by measuring the system models from physical sensors to virtual sensors, which will be used in the online operation of the virtual sensing ANC algorithm. Hence, we attempt to achieve the maximum noise reduction near the eardrums by applying the virtual sensing technique to the head-mounted ANC system. However, it is impossible to place the microphone near the eardrums. Therefore, the system models from physical sensors to virtual sensors are estimated using the Head And Torso Simulator (HATS) instead of human ears. Some simulation, experimental, and subjective assessment results demonstrate that the head-mounted ANC system with virtual sensing is superior to that without virtual sensing in terms of the noise reduction ability at the desired locations.

  19. Io’s active volcanoes during the New Horizons era: Insights from New Horizons imaging

    NASA Astrophysics Data System (ADS)

    Rathbun, J. A.; Spencer, J. R.; Lopes, R. M.; Howell, R. R.

    2014-03-01

    In February 2007, the New Horizons spacecraft flew by the Jupiter system, obtaining images of Io, the most volcanically active body in the Solar System. The Multicolor Visible Imaging Camera (MVIC), a four-color (visible to near infrared) camera, obtained 17 sets of images. The Long-Range Reconnaissance Imager (LORRI), a high-resolution panchromatic camera, obtained 190 images, including many of Io eclipsed by Jupiter. We present a complete view of the discrete point-like emission sources in all images obtained by these two instruments. We located 54 emission sources and determined their brightnesses. These observations, the first that observed individual Ionian volcanoes on short timescales of seconds to minutes, demonstrate that the volcanoes have stable brightnesses on these timescales. The active volcanoes Tvashtar (63N, 124W) and E. Girru (22N, 245W) were observed by both LORRI and MVIC, both in the near-infrared (NIR) and methane (CH4) filters. Tvashtar was additionally observed in the red filter, which allowed us to calculate a color temperature of approximately 1200 K. We found that, with some exceptions, most of the volcanoes frequently active during the Galileo era continued to be active during the New Horizons flyby. We found that none of the seven volcanoes observed by New Horizons multiple times over short timescales showed substantial changes on the order of seconds and only one, E. Girru exhibited substantial variation over minutes to days, increasing by 25% in just over an hour and decreasing by a factor of 4 over 6 days. Observations of Tvashtar are consistent with a current eruption similar to previously observed eruptions and are more consistent with the thermal emission of a lava flow than the fire fountains inferred from the November 1999 observations. These data also present new puzzles regarding Ionian volcanism. Since there is no associated surface change or low albedo feature that could be identified nearby, the source of the emission from

  20. Understanding how active volcanoes work: a contribution from synchrotron X-ray computed microtomography

    NASA Astrophysics Data System (ADS)

    Polacci, M.; Baker, D. R.; Mancini, L.

    2009-04-01

    Volcanoes are complex systems that require the integration of many different geoscience disciplines to understand their behaviour and to monitor and forecast their activity. In the last two decades an increasing amount of information on volcanic processes has been obtained by studying the textures and compositions of volcanic rocks. Five years ago we started a continuing collaboration with the SYRMEP beamline of Elettra Sincrotrone, a third generation synchrotron light source near Trieste, Italy, with the goal of performing high-resolution, phase-contrast X-ray tomographic scans and reconstructing 3-D digital volumes of volcanic specimens. These volumes have been then used for the visualization of the internal structure of rocks and for the quantification of rock textures (i.e., vesicle and crystal volume fraction, individual vesicle volumes and shapes, vesicle connectivity, vesicle volume distributions, permeability simulations etc.). We performed tomographic experiments on volcanic products erupted from different hazardous volcanic systems in Italy and around the world: Campi Flegrei, Stromboli, Etna (Southern Italy), Villarrica (Chile), Yasur and Ambrym (Vanuatu Islands). As an example, we used the results of these studies to constrain the dynamics of vesiculation and degassing in basaltic (Polacci et al., 2006; Burton et al., 2007; Colò et al., 2007; Andronico et al., 2008; Polacci et al., 2008a) and trachytic (Piochi et al., 2008) magmas. A better knowledge of how gas is transported and lost from magmas has led us in turn to draw new implications on the eruptive style of these active, hazardous volcanoes (Polacci et al., 2008b). Work in progress consists of optimizing our procedure by establishing a precise protocol that will enable us to quantitatively study the 3-D texture and composition of rocks in a statistically representative way. Future work will concentrate on the study of the spatial relations between phases (crystals, vesicles and glass) in rocks

  1. 1997 volcanic activity in Alaska and Kamchatka: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Wallace, Kristi L.

    1999-01-01

    The Alaska Volcano Observatory (AVO) monitors over 40 historically active volcanoes along the Aleutian Arc. Twenty are seismically monitored and for the rest, the AVO monitoring program relies mainly on pilot reports, observations of local residents and ship crews, and daily analysis of satellite images. In 1997, AVO responded to eruptive activity or suspect volcanic activity at 11 volcanic centers: Wrangell, Sanford, Shrub mud volcano, Iliamna, the Katmai group (Martin, Mageik, Snowy, and Kukak volcanoes), Chiginagak, Pavlof, Shishaldin, Okmok, Cleveland, and Amukta. Of these, AVO has real-time, continuously recording seismic networks at Iliamna, the Katmai group, and Pavlof. The phrase “suspect volcanic activity” (SVA), used to characterize several responses, is an eruption report or report of unusual activity that is subsequently determined to be normal or enhanced fumarolic activity, weather-related phenomena, or a non-volcanic event. In addition to responding to eruptive activity at Alaska volcanoes, AVO also disseminated information for the Kamchatkan Volcanic Eruption Response Team (KVERT) about the 1997 activity of 5 Russian volcanoes--Sheveluch, Klyuchevskoy, Bezymianny, Karymsky, and Alaid (SVA). This report summarizes volcanic activity and SVA in Alaska during 1997 and the AVO response, as well as information on the reported activity at the Russian volcanoes. Only those reports or inquiries that resulted in a “significant” investment of staff time and energy (here defined as several hours or more for reaction, tracking, and follow-up) are included. AVO typically receives dozens of reports throughout the year of steaming, unusual cloud sightings, or eruption rumors. Most of these are resolved quickly and are not tabulated here as part of the 1997 response record.

  2. Forecasts and predictions of eruptive activity at Mount St. Helens, USA: 1975-1984

    USGS Publications Warehouse

    Swanson, D.A.; Casadevall, T.J.; Dzurisin, D.; Holcomb, R.T.; Newhall, C.G.; Malone, S.D.; Weaver, C.S.

    1985-01-01

    Public statements about volcanic activity at Mount St. Helens include factual statements, forecasts, and predictions. A factual statement describes current conditions but does not anticipate future events. A forecast is a comparatively imprecise statement of the time, place, and nature of expected activity. A prediction is a comparatively precise statement of the time, place, and ideally, the nature and size of impending activity. A prediction usually covers a shorter time period than a forecast and is generally based dominantly on interpretations and measurements of ongoing processes and secondarily on a projection of past history. The three types of statements grade from one to another, and distinctions are sometimes arbitrary. Forecasts and predictions at Mount St. Helens became increasingly precise from 1975 to 1982. Stratigraphic studies led to a long-range forecast in 1975 of renewed eruptive activity at Mount St. Helens, possibly before the end of the century. On the basis of seismic, geodetic and geologic data, general forecasts for a landslide and eruption were issued in April 1980, before the catastrophic blast and landslide on 18 May 1980. All extrusions except two from June 1980 to the end of 1984 were predicted on the basis of integrated geophysical, geochemical, and geologic monitoring. The two extrusions that were not predicted were preceded by explosions that removed a substantial part of the dome, reducing confining pressure and essentially short-circuiting the normal precursors. ?? 1985.

  3. Sulfur dioxide emissions from la soufriere volcano, st. Vincent, west indies.

    PubMed

    Hoff, R M; Gallant, A J

    1980-08-22

    During the steady-state period of activity of La Soufriere Volcano in 1979, the mass emissions of sulfur dioxide into the troposphere amounted to a mean value of 339 +/- 126 metric tons per day. This value is similar to the sulfur dioxide emissions of other Central American volcanoes but less than those measured at Mount Etna, an exceptionally strong volcanic source of sulfur dioxide.

  4. Sulfur dioxide emissions from La Soufriere Volcano, St. Vincent, West Indies

    SciTech Connect

    Hoff, R.M.; Gallant, A.J.

    1980-08-22

    During the steady-state period of activity of La Soufriere Volcano in 1979, the mass emissions of sulfur dioxide into the troposphere amounted to a mean value of 339 +- 126 metric tons per day. This value is similar to the sulfur dioxide emissions of other Central American volcanoes but less than those measured at Mount Etna, an exceptionally strong volcanic source of sulfur dioxide.

  5. Sex differences in the inhibition by ATD of testosterone-activated mounting behavior in guinea pigs.

    PubMed

    Roy, M M; Goy, R W

    1988-09-01

    Adult male and female guinea pigs from a genetically heterogeneous stock were gonadectomized and tested for mounting behavior before and during various treatments with testosterone cypionate (TC) alone or in combination with an aromatase inhibitor, 1,4,6-androstatriene-3,17-dione (ATD). ATD was implanted subdermally in Silastic capsules (either 1 or 2 in females; 2 or 3 in males). In females 2 capsules of ATD completely blocked the behavioral effects of TC, and 1 capsule was an effective blocker in 58% of the females. The blocking effect was reversed by injection of diethylstilbestrol. In males, there was no measurable effect of ATD on mounting activity even when 3 capsules were implanted. Moreover, the TC induction of higher components of male sexual behavior (intromission and ejaculation) was also not impaired by ATD. Results are interpreted as indicating that either the process of male sexual differentiation or the male genotype eliminates the requirement for aromatization in androgenic activation of sexual behavior.

  6. Stratigraphic constraints for explosive activity in the past 100 ka at Etna Volcano, Italy

    NASA Astrophysics Data System (ADS)

    Coltelli, Mauro; Del Carlo, Paola; Vezzoli, Luigina

    2000-08-01

    The pyroclastic deposits of Etna have been correlated over the whole volcanic edifice for the first time, allowing the construction of a continuous record of tephra-producing events, which extends from approximately 100 ka to the Present. In this interval, five main periods of explosive activity have been identified: (a) 100-ka strombolian to subplinian activity; (b) 80- to 100-ka plinian benmoreitic activity; (c) 16- to 80-ka strombolian to subplinian from basaltic to mugearitic activity; (d) 15.5- to 15-ka plinian benmoreitic activity accompanying the caldera-forming eruptions of the Ellittico Volcano; and (e) the most recent 13-ka basaltic explosive activity of strombolian and subplinian type of the present edifice that also includes the 122-B.C. plinian eruption. This study results in a semi-quantitative and in some cases quantitative definition of the intensity and chronology of the explosive activity at Etna. Moreover, this work gives a new significance to the volcanic hazards of Etna, a volcano generally considered to be the site of gentle effusive eruptions.

  7. Holocene eruptive activity of El Chichon volcano, Chiapas, Mexico

    NASA Technical Reports Server (NTRS)

    Tilling, R. I.; Rubin, M.; Sigurdsson, H.; Carey, S.; Duffield, W. A.; Rose, W. I.

    1984-01-01

    Geologic and radiometric-age data indicate that El Chichon was frequently and violently active during the Holocene, including eruptive episodes about 600, 1250, and 1700 years ago and several undated, older eruptions. These episodes, involving explosive eruptions of sulfur-rich magma and associated domegrowth processes, were apparently separated by intervals of approximately 350 to 650 years. Some of El Chichon's eruptions may correlate with unusual atmospheric phenomena around A.D. 1300 and possibly A.D. 623.

  8. Holocene eruptive activity of El Chichon volcano, Chiapas, Mexico

    NASA Astrophysics Data System (ADS)

    Tilling, R. I.; Rubin, M.; Sigurdsson, H.; Carey, S.; Duffield, W. A.; Rose, W. I.

    1984-05-01

    Geologic and radiometric-age data indicate that El Chichon was frequently and violently active during the Holocene, including eruptive episodes about 600, 1250, and 1700 years ago and several undated, older eruptions. These episodes, involving explosive eruptions of sulfur-rich magma and associated domegrowth processes, were apparently separated by intervals of approximately 350 to 650 years. Some of El Chichon's eruptions may correlate with unusual atmospheric phenomena around A.D. 1300 and possibly A.D. 623.

  9. Chemical evolution of thermal springs at Arenal Volcano, Costa Rica: Effect of volcanic activity, precipitation, seismic activity, and Earth tides

    NASA Astrophysics Data System (ADS)

    López, D. L.; Bundschuh, J.; Soto, G. J.; Fernández, J. F.; Alvarado, G. E.

    2006-09-01

    Arenal Volcano in NW Costa Rica, Central America has been active during the last 37 years. However, only relatively low temperature springs have been identified on its slopes with temperatures less than around 60 °C. The springs are clustered on the NE and NW slopes of the volcano, close to contacts between the recent and older volcanic products or at faults that intercept the volcano. This volcano is located in a rain forest region with annual rainfall averaging around 5 m. During the last 15 years, the temperature and chemical composition of 4 hot springs and 2 cold springs have been monitored approximately every 3 months. In addition, two more thermal sites were identified recently and sampled, as well as two boreholes located on a fault NE of the volcano. Scatter plots of chemical species such as Cl and B suggest that the waters in these discharges belong to the same aquifer with a saline end member similar to Río Tabacón at the beginning of the study period (1990) and the deeper borehole (B-2) in 2004. The waters of Quebrada Bambú and Quebrada Fría represent a more dilute end member. Both long-term (over the 15 years) and short-term or seasonal decreases in concentration and steady or decreasing temperature are noted in NW springs. Springs located at the NE show increasing temperatures and ion concentrations, except for bicarbonate that has decreased in concentration for all the springs. This behavior is likely associated with a shallow source for the solutes and heat for this aquifer. To the NW the early lavas and pyroclastic flows have been cooling down, decreasing the contribution of leaching products to the infiltrating waters. To the NE, pyroclastic flows to the N during the last decade are contributing increasing concentrations of solutes and heat throughout water infiltration and circulation within the faults and the surficial drainage that has a NE regional trend. For the short-term or seasonal variations, concentrations of chemical constituents

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

    USGS Publications Warehouse

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

    1988-01-01

    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

  11. Methanogenic diversity and activity in hypersaline sediments of the centre of the Napoli mud volcano, Eastern Mediterranean Sea.

    PubMed

    Lazar, Cassandre Sara; Parkes, R John; Cragg, Barry A; L'Haridon, Stéphane; Toffin, Laurent

    2011-08-01

    Submarine mud volcanoes are a significant source of methane to the atmosphere. The Napoli mud volcano, situated in the brine-impacted Olimpi Area of the Eastern Mediterranean Sea, emits mainly biogenic methane particularly at the centre of the mud volcano. Temperature gradients support the suggestion that Napoli is a cold mud volcano with moderate fluid flow rates. Biogeochemical and molecular genetic analyses were carried out to assess the methanogenic activity rates, pathways and diversity in the hypersaline sediments of the centre of the Napoli mud volcano. Methylotrophic methanogenesis was the only significant methanogenic pathway in the shallow sediments (0-40 cm) but was also measured throughout the sediment core, confirming that methylotrophic methanogens could be well adapted to hypersaline environments. Hydrogenotrophic methanogenesis was the dominant pathway below 50 cm; however, low rates of acetoclastic methanogenesis were also present, even in sediment layers with the highest salinity, showing that these methanogens can thrive in this extreme environment. PCR-DGGE and methyl coenzyme M reductase gene libraries detected sequences affiliated with anaerobic methanotrophs (mainly ANME-1) as well as Methanococcoides methanogens. Results show that the hypersaline conditions in the centre of the Napoli mud volcano influence active biogenic methane fluxes and methanogenic/methylotrophic diversity.

  12. Timing of degassing and plagioclase growth in lavas erupted from Mount St. Helens, 2004-2005, from 210Po-210Pb-226Ra disequilibria: Chapter 37 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Reagan, Mark K.; Cooper, Kari M.; Pallister, John S.; Thornber, Carl R.; Wortel, Matthew; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    Disequilibrium between 210Po, 210Pb, and 226Ra was measured on rocks and plagioclase mineral separates erupted during the first year of the ongoing eruption of Mount St. Helens. The purpose of this study was to monitor the volatile fluxing and crystal growth that occurred in the weeks, years, and decades leading up to eruption. Whole-rock samples were leached in dilute HCl to remove 210Po precipitated in open spaces. Before leaching, samples had variable initial (210Po) values, whereas after leaching, the groundmasses of nearly all juvenile samples were found to have had (210Po) ≈ 0 when they erupted. Thus, most samples degassed 210Po both before and after the magmas switched from open- to closed-system degassing. All juvenile samples have (210Pb)/(226Ra) ratios within 2 δ of equilibrium, suggesting that the magmas involved in the ongoing eruption did not have strong, persistent fluxes of 222Rn in or out of magmas during the decades and years leading to eruption. These equilibrium values also require a period of at least a century after magma generation and the last significant differentiation of the Mount St. Helens dacites. Despite this, the elevated (210Pb)/(226Ra) value measured in a plagioclase mineral separate from lava erupted in 2004 suggests that a significant proportion of this plagioclase grew within a few decades of eruption. The combined dataset suggests that for most 2004-5 lavas, the last stage of open-system degassing of the dacite magmas at Mount St. Helens is confined to the period between 1-2 years and 1-2 weeks before eruption, whereas plagioclase large enough to be included in the mineral separate grew around the time of the 1980s eruption or earlier.

  13. Monitoring eruption activity from temporal stress changes at Mt. Ontake volcano, Japan

    NASA Astrophysics Data System (ADS)

    Terakawa, T.; Kato, A.; Yamanaka, Y.; Maeda, Y.; Horikawa, S.; Matsuhiro, K.; Okuda, T.

    2015-12-01

    On 27 September 2014, Mt. Ontake in Japan produced a phreatic (steam type) eruption with a Volcanic Explosivity Index value of 2 after being dormant for seven years. The local stress field around volcanoes is the superposition of the regional stress field and stress perturbations related to volcanic activity. Temporal stress changes over periods of weeks to months are generally attributed to volcanic processes. Here we show that monitoring temporal changes in the local stress field beneath Mt. Ontake, using focal mechanism solutions of volcano-tectonic (VT) earthquakes, is an effective tool for assessing the state of volcanic activity. We estimated focal mechanism solutions of 157 VT earthquakes beneath Mt. Ontake from August 2014 to March 2015, assuming that the source was double-couple. Pre-eruption seismicity was dominated by normal faulting with east-west tension, whereas most post-eruption events were reverse faulting with east-west compression. The misfit angle between observed slip vectors and those derived theoretically from the regional (i.e., background) stress pattern is used to evaluate the deviation of the local stress field, or the stress perturbation related to volcanic activity. The moving average of misfit angles tended to exceed 90° before the eruption, and showed a marked decrease immediately after the eruption. This indicates that during the precursory period the local stress field beneath Mt. Ontake was rotated by stress perturbations caused by the inflation of magmatic/hydrothermal fluids. Post-eruption events of reverse faulting acted to shrink the volcanic edifice after expulsion of volcanic ejecta, controlled by the regional stress field. The misfit angle is a good indicator of the state of volcanic activity. The monitoring method by using this indicator is applicable to other volcanoes and may contribute to the mitigation of volcanic hazards.

  14. Structural-optical integrated analysis on the large aperture mirror with active mounting

    NASA Astrophysics Data System (ADS)

    Ren, Zhiyuan; Zhu, Jianqiang; Liu, Zhigang

    2016-11-01

    Deformation of the large aperture mirror caused by the external environment load seriously affects the optical performance of the optical system, and there is a limit to develop the shape quality of large aperture mirror with traditional mounting method. It is effective way to reduce the optical mirror distortion with active support method, and the structural-optical integrated method is the effective means to assess the merits of the mounting for large aperture mirror. Firstly, we proposes a new support scheme that uses specific boundary constraints on the large lens edges and imposes flexible torque to resist deformation induced by gravity to improve surface quantity of large aperture mirror. We calculate distortion of the large aperture mirror at the edges of the flexible torque respectively with the finite element method; secondly, we extract distortion value within clear aperture of the mirror with MATLAB, solve the corresponding Zernike polynomial coefficients; lastly, we obtain the peak-valley value (PV) and root mean square value (RMS) with optical-structural integrated analysis . The results for the 690x400x100mm mirror show that PV and RMS values within the clear aperture with 0.4MPa torques than the case without applying a flexible torque reduces 82.7% and 72.9% respectively. The active mounting on the edge of the large aperture mirror can greatly improve the surface quality of the large aperture mirror.

  15. Mount St. Helens

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) image of Mount St. Helens was captured one week after the March 8, 2005, ash and steam eruption, the latest activity since the volcano's reawakening in September 2004. The new lava dome in the southeast part of the crater is clearly visible, highlighted by red areas where ASTER's infrared channels detected hot spots from incandescent lava. The new lava dome is 155 meters (500 feet) higher than the old lava dome, and still growing.

    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: 21.9 by 24.4 kilometers (13.6 by 15.1 miles) Location: 46.2 degrees North latitude, 122.2 degrees West longitude Orientation: North at top Image Data: ASTER bands 8, 3, and 1 Original Data Resolution

  16. Effects of lava-dome growth on the crater glacier of Mount St. Helens, Washington: Chapter 13 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Walder, Joseph S.; Schilling, Steve P.; Vallance, James W.; LaHusen, Richard G.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    The process of lava-dome emplacement through a glacier was observed for the first time as the 2004-6 eruption of Mount St. Helens proceeded. The glacier that had grown in the crater since the cataclysmic 1980 eruption was split in two by the new lava dome. The two parts of the glacier were successively squeezed against the crater wall. Photography, photogrammetry, and geodetic measurements document glacier deformation of an extreme variety, with strain rates of extraordinary magnitude as compared to normal temperate alpine glaciers. Unlike such glaciers, the Mount St. Helens crater glacier shows no evidence of either speed-up at the beginning of the ablation season or diurnal speed fluctuations during the ablation season. Thus there is evidently no slip of the glacier over its bed. The most reasonable explanation for this anomaly is that meltwater penetrating the glacier is captured by a thick layer of coarse rubble at the bed and then enters the volcano’s groundwater system rather than flowing through a drainage network along the bed. Mechanical consideration of the glacier-squeeze process also leads to an estimate for the driving pressure applied by the growing lava dome.

  17. Mount Vesuvius: 2000 years of volcanological observations

    NASA Astrophysics Data System (ADS)

    Scandone, Roberto; Giacomelli, Lisetta; Gasparini, Paolo

    1993-11-01

    Mount Vesuvius had eruptions ranging between VEI 5+ to 0-1 during the last 2000 years. Infrequent explosive eruptions are recorded during the period 79 AD to 1631. Since the violent explosive eruption of 1631, the volcano has been in persistent activity, rebuilding the morphology that it had before that eruption. A succession of explosive and effusive eruptions occurred until 1944, with a predominance of short and violent episodes until 1872 and longer effusive eruptions since that date. Two factors mainly controlled the character of volcanic activity during this period: (1) the strength of the cone, which allowed, in the earlier period, an easy fracturing, rapid drainage, and pressure release of the magma column; (2) the interaction between magma and water, which enhanced the explosivity of several eruptions. The volcano appears to have reached a stage of quiescence because it finally attained a shape of equilibrium in which the height of the mountain is sufficient to counterbalance the buoyancy of the magma.

  18. Coulomb stress analysis of West Halmahera earthquake mw=7.2 to mount Soputan and Gamalama volcanic activities

    NASA Astrophysics Data System (ADS)

    Sinaga, G. H. D.; Zarlis, M.; Sitepu, M.; Prasetyo, R. A.; Simanullang, A.

    2017-02-01

    West Halmahera is the convergency of three plates, namely the Philippines plate, the Eurasian plate, and the Pasific plate. The location of the West Halmahera is located in the thress plates, so the Western Halmahera potentially earthquake-prone areas. Some events increased activity of Mount Soputan and Mount Gamalama preceded by a massive earthquake. This research was conducted in the BMKG Region I Medan. This research uses Coulomb Stress Model. Coulomb Stress Model was used to show increasing and decreasing stress consequence from earthquake in the area of West Halmahera. Data such as the earthquake magnitude, earthquake depth, and Focal Mechanism required as input models. The data obtained from BMKG, Global CMT, and PVMBG. The result of data analyzed show an increase in the coulomb stress distribution at Mount Soputan 0.023 bar and 0.007 bar in mountain Gamalama. This stress followed by increased volcanic activity of the mount Soputan and mount Gamalama with freatic eruption type.

  19. International Collaboration on Building Local Technical Capacities for Monitoring Volcanic Activity at Pacaya Volcano, Guatemala.

    NASA Astrophysics Data System (ADS)

    Escobar-Wolf, R. P.; Chigna, G.; Morales, H.; Waite, G. P.; Oommen, T.; Lechner, H. N.

    2015-12-01

    Pacaya volcano is a frequently active and potentially dangerous volcano situated in the Guatemalan volcanic arc. It is also a National Park and a major touristic attraction, constituting an important economic resource for local municipality and the nearby communities. Recent eruptions have caused fatalities and extensive damage to nearby communities, highlighting the need for risk management and loss reduction from the volcanic activity. Volcanic monitoring at Pacaya is done by the Instituto Nacional de Sismologia, Vulcanologia, Meteorologia e Hidrologia (INSIVUMEH), instrumentally through one short period seismic station, and visually by the Parque Nacional Volcan de Pacaya y Laguna de Calderas (PNVPLC) personnel. We carry out a project to increase the local technical capacities for monitoring volcanic activity at Pacaya. Funding for the project comes from the Society of Exploration Geophysicists through the Geoscientists Without Borders program. Three seismic and continuous GPS stations will be installed at locations within 5 km from the main vent at Pacaya, and one webcam will aid in the visual monitoring tasks. Local educational and outreach components of the project include technical workshops on data monitoring use, and short thesis projects with the San Carlos University in Guatemala. A small permanent exhibit at the PNVPLC museum or visitor center, focusing on the volcano's history, hazards and resources, will also be established as part of the project. The strategy to involve a diverse group of local collaborators in Guatemala aims to increase the chances for long term sustainability of the project, and relies not only on transferring technology but also the "know-how" to make that technology useful. Although not a primary research project, it builds on a relationship of years of joint research projects at Pacaya between the participants, and could be a model of how to increase the broader impacts of such long term collaboration partnerships.

  20. What drives centuries-long polygenetic scoria cone activity at Barren Island volcano?

    NASA Astrophysics Data System (ADS)

    Sheth, Hetu

    2014-12-01

    Barren Island in the Andaman Sea is an active mafic stratovolcano, which had explosive and effusive eruptions, followed by caldera formation, in prehistoric time (poorly dated). A scoria cone within the caldera, marking volcanic resurgence, was active periodically from 1787 to 1832 (the historic eruptions). Since 1991, the same scoria cone has produced six eruptions, commonly including lava flows. Links between Barren Island's eruptions and giant earthquakes (such as the 26 December 2004 Great Sumatra megathrust earthquake) have been suggested, though there is no general correlation between them. The ≥ 227-year-long activity of the scoria cone, named here Shanku ("cone"), is normally driven by purely magmatic processes. I present a "source to surface" model for Barren Island and Shanku, including the source region, deeper and shallow magma chambers, volcanotectonics, dyking from magma chambers, and eruptions and eruptive style as controlled by crustal stresses, composition and volatile content. Calculations show that dykes ~ 0.5 m thick and a few hundred meters long, originating from shallow-level magma chambers (~ 5 km deep), are suitable feeders of the Shanku eruptions. Shanku, a polygenetic scoria cone (at least 13 eruptions since 1787), has three excellent analogues, namely Anak Krakatau (40 eruptions since 1927), Cerro Negro (23 eruptions since 1850), and Yasur (persistent activity for the past hundreds of years). This is an important category of volcanoes, gradational between small "monogenetic" scoria cones and larger "polygenetic" volcanoes.

  1. Source mechanism of very-long-period signals accompanying dome growth activity at Merapi volcano, Indonesia

    USGS Publications Warehouse

    Hidayat, D.; Chouet, B.; Voight, B.; Dawson, P.; Ratdomopurbo, A.

    2002-01-01

    Very-long-period (VLP) pulses with period of 6-7s, displaying similar waveforms, were identified in 1998 from broadband seismographs around the summit crater. These pulses accompanied most of multiphase (MP) earthquakes, a type of long-period event locally defined at Merapi Volcano. Source mechanisms for several VLP pulses were examined by applying moment tensor inversion to the waveform data. Solutions were consistent with a crack striking ???70?? and dipping ???50?? SW, 100m under the active dome, suggest pressurized gas transport involving accumulation and sudden release of 10-60 m3 of gas in the crack over a 6s interval.

  2. Systems analysis of the installation, mounting, and activation of emergency locator transmitters in general aviation aircraft

    NASA Technical Reports Server (NTRS)

    Hall, D. S.

    1980-01-01

    A development program was developed to design and improve the Emergency Locator Transmitter (ELT) transmitter and to improve the installation in the aircraft and its activation subsystem. There were 1135 general aviation fixed wing aircraft accident files reviewed. A detailed description of the damage to the aircraft was produced. The search aspects of these accidents were studied. As much information as possible about the ELT units in these cases was collected. The data should assist in establishing installation and mounting criteria, better design standards for activation subsystems, and requirements for the new ELT system design in the area of crashworthiness.

  3. Mantle to surface gas triggers of magmatic activity at Erebus volcano, Antarctica

    NASA Astrophysics Data System (ADS)

    Oppenheimer, C.; Moretti, R.; Kyle, P.

    2009-04-01

    Intraplate volcanoes are associated with extensional tectonics, mantle upwelling and high heat flow. Erupted magmas have an alkaline nature and are rich in volatiles, especially CO2, that are inherited from fluid-rich magmatic sources in the mantle. Localized alkaline centers emit gas fluxes that exceed what can be sustained by the rates of magma erupted. At Mount Erebus this dichotomy is evidenced by open-path Fourier transform infrared (FTIR) spectroscopy of gases released from the lava lake. Different gas signatures are associated with explosive and non-explosive gas emissions, representative of volatile contents and redox conditions that identify the overlap between shallow and deep degassing sources. We show that this multiple signature of magma degassing provides a unique probe for magma differentiation and transfer of CO2-rich oxidized fluids from lithospheric roots up to the surface, and show how these processes operate in time and space. Magma deeper than 4 km equilibrates under vapour buffered conditions, whereas shallower magmas allow deep, CO2-rich fluids to accumulate and prior to release either via open-system degassing conditions and reduced oxidation states, or as volatile-enriched, phonolitic blobs that preserve the deep oxidized signature, and ascend as a closed-system to explode at the surface during Strombolian phases.

  4. A Discussion of Zero Spring Rate Mechanisms Used for the Active Isolation Mount Experiment

    NASA Technical Reports Server (NTRS)

    Teter, John E., Jr.

    1999-01-01

    In the summer of 1995 the Structural Dynamics Branch at NASA Langley Research Center set out to conceive a small, lightweight, low frequency isolation mount that could be used for spaceflight experiments. The Engineering Design Branch undertook the task of developing the isolation mount. This report describes the engineering process that led to three phases of a study entitled "Active Isolation Mounts" (AIM). A zero spring rate mechanism was used to achieve low fundamental frequencies for a payloads in the 1 to 10 pound range. It worked by balancing both a positive and a negative stiffness so that the net result was a small positive stiffness. The study demonstrated devices that could reduce the initial corner frequency by a factor of six for brief periods and a factor of two for extended periods. The designs were relatively simple and minimized weight, volume, and power. They could be scaled down and they were made of spaceflight compatible materials. All designs offered the ability to continuously vary the fundamental frequency. Yet, the goal of reducing the frequency by an order of magnitude was not achieved because the systems were too unstable at low frequencies. There was a trade between performance and stability.

  5. Control of seismic and operational vibrations of rotating machines using semi-active mounts

    NASA Astrophysics Data System (ADS)

    Rana, R.; Soong, T. T.

    2004-06-01

    A dual isolation problem for rotating machines consists of isolation of housing structures from the machine vibrations and protection of machines during an earthquake to maintain their functionality. Desirable characteristics of machine mounts for the above two purposes can differ significantly due to difference in nature of the excitation and performance criteria in the two situations. In this paper, relevant response quantities are identified that may be used to quantify performance and simplified models of rotating machines are presented using which these relevant response quantities may be calculated. Using random vibration approach with a stationary excitation, it is shown that significant improvement in seismic performance is achievable by proper mount design. Results of shaking table experiments performed with a realistic setup using a centrifugal pump are presented. It is concluded that a solution to this dual isolation problem lies in a semi-active mount capable switching its properties from ‘operation-optimum’ to ‘seismic-optimum’ at the onset of a seismic event.

  6. Very Long Period Seismicity Accompanying Increasing Shallower Activity at Cotopaxi Volcano

    NASA Astrophysics Data System (ADS)

    Arias, G.; Molina Polania, C. I.; Ruiz, M. C.; Kumagai, H.; Hernandez, S.; Plain, M.; Mothes, P. A.; Yepez, M.; Barrington, C.; Hidalgo, S.

    2015-12-01

    Cotopaxi is an andesitic stratovolcano, located in the highland region of Ecuador, which renewed its activity in April 2015, showing an increased number of volcano-tectonic (VT), long-period (LP), very long period events (VLP), and tremors. The VLP events were recorded in several episodes between 2002 and 2014, and have been interpreted as volumetric changes due to the release of gas and subsequent pressure drop and recovery in the magma intrusion. The two peaks of VLP seismicity in June 2002 and April 2015 preceded an increase of surficial activity (fumarolic increase) and the deformation data during those episodes suggested a small intrusion of magma beneath the volcano.Using polarization analysis, we found that most of these events were located at 2-3 km depth beneath the volcano summit, while the deformation data suggests the intrusion is deeper (5-10 km deep). Using tiltmeter data, Mogi point source modelling on successive periods of inflation and deflation show a significant shallowing of sources since the end of May 2015, matching the recent very large spike in SO2 emissions (~3000 t/d). From mid-February until the gas emission spikes in May 2015, Mogi source modelling has indicated inflation/deflation events at 11 to 10 km depth, having shallowed to a depth of between 8 and 7 km after the SO2 emission increase. Shallow source volumes suggested by deformation indicate values of 4 - 31x106 m3, with the most recent, most shallow inflation currently at 8x106 m3.

  7. Water chemistry of lakes related to active and inactive Mexican volcanoes

    NASA Astrophysics Data System (ADS)

    Armienta, María Aurora; Vilaclara, Gloria; De la Cruz-Reyna, Servando; Ramos, Silvia; Ceniceros, Nora; Cruz, Olivia; Aguayo, Alejandra; Arcega-Cabrera, Flor

    2008-12-01

    Water chemistry of crater lakes, maars and water reservoirs linked to some Mexican volcanoes within and outside the Mexican Volcanic Belt has been determined for several years and examined regarding environmental and volcanic factors. All the analyzed lakes are relatively small with a maximum depth of 65 m, and are located in regions with different climates, from semi-arid to very humid, with altitudes ranging from 100 to more than 4000 m a.s.l. Crater lakes in active volcanoes (El Chichón, Popocatépetl) have very low pH, moderate to high temperatures and major ion concentrations varying with the level of volcanic unrest. Lakes in sub-arid and temperate-arid regions (like maars in Puebla and Guanajuato states) show high alkalinity and pH, with bicarbonate/carbonate, chloride, sodium and magnesium as predominant ions. Lakes located in humid climates (Central Michoacán and Veracruz state) have low mineralization and near-neutral pH values. In general, conservative dissolved ions and conductivity appear to be mostly controlled by precipitation/evaporation and by the ionic concentration of groundwater inputs. Calcium, magnesium, sulfate concentrations and pH are strongly influenced by volcanic-rock or volcanic gas interactions with water. The influence of low-level volcanic activity on crater lakes may be obscured by water-rock interactions, and climatic factors. One of the aims of this paper is to define the relative influence of these factors searching for a reference frame to recognize the early volcanic precursors in volcano-related lakes.

  8. Extrusion rate of the Mount St. Helens lava dome estimated from terrestrial imagery, November 2004-December 2005: Chapter 12 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Major, Jon J.; Kingsbury, Cole G.; Poland, Michael P.; LaHusen, Richard G.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    Oblique, terrestrial imagery from a single, fixed-position camera was used to estimate linear extrusion rates during sustained exogenous growth of the Mount St. Helens lava dome from November 2004 through December 2005. During that 14-month period, extrusion rates declined logarithmically from about 8-10 m/d to about 2 m/d. The overall ebbing of effusive output was punctuated, however, by episodes of fluctuating extrusion rates that varied on scales of days to weeks. The overall decline of effusive output and finer scale rate fluctuations correlated approximately with trends in seismicity and deformation. Those correlations portray an extrusion that underwent episodic, broad-scale stick-slip behavior superposed on the finer scale, smaller magnitude stick-slip behavior that has been hypothesized by other researchers to correlate with repetitive, nearly periodic shallow earthquakes.

  9. Spontaneous Potential Anomalies on Active Volcanoes: New Time and Spatial Series from Masaya, Telica, and Cerro Negro, Nicaragua

    NASA Astrophysics Data System (ADS)

    Lehto, H.; Pearson, S.; Connor, C.; Sanford, W.; Saballos, A.

    2006-12-01

    Considerable effort worldwide has gone into monitoring heat and mass transfer at active volcanoes because such information may provide clues about changes in volcanic activity and impending eruptions. Here we present new time and spatial series of spontaneous potential (SP) anomalies from Masaya and Telica volcanoes, and spatial series collected at Cerro Negro volcano. Our primary purpose is to investigate correlations between more easily and cheaply monitored SP and CO2 gas flux, measured by an infrared CO2 analysis system. SP data were collected using nonpolarizing Pb-PbCL2 electrodes that we constructed following the approach of Petiau. Mapping at both Masaya, and Cerro Negro reveals broad correlations between SP anomalies and CO2 flux through soils. In addition, we monitored temperature, barometric pressure, and rainfall at one minute intervals from May-August, 2006 at Masaya and Telica volcanoes. During this period it is clear that SP responds to changes in volcanic activity, with transient anomalies of 75 mV as well as atmospheric forcing due to rainfall, producing anomalies of 56 mV and related phenomena. Preliminary lab experiments provide further details of the electrokinetic origin of these SP anomalies. Our preliminary work supports the idea that large and inexpensive networks of electrodes might track changes in SP anomalies associated with changes in mass flow at active volcanoes.

  10. Mount St. Helens Rebirth

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The catastrophic eruption of Mt. St. Helens 20 years ago today (on May 18, 1980), ranks among the most important natural events of the twentieth century in the United States. Because Mt. St. Helens is in a remote area of the Cascades Mountains, only a few people were killed by the eruption, but property damage and destruction totaled in the billions of dollars. Mount St. Helens is an example of a composite or stratovolcano. These are explosive volcanoes that are generally steep-sided, symmetrical cones built up by the accumulation of debris from previous eruptions and consist of alternating layers of lava flows, volcanic ash and cinder. Some of the most photographed mountains in the world are stratovolcanoes, including Mount Fuji in Japan, Mount Cotopaxi in Ecuador, Mount Hood in Oregon, and Mount Rainier in Washington. The recently erupting Mount Usu on the island of Hokkaido in Japan is also a stratovolcano. Stratovolcanoes are characterized by having plumbing systems that move magma from a chamber deep within the Earth's crust to vents at the surface. The height of Mt. St. Helens was reduced from about 2950 m (9677 ft) to about 2550 m (8364 ft) as a result of the explosive eruption on the morning of May 18. The eruption sent a column of dust and ash upwards more than 25 km into the atmosphere, and shock waves from the blast knocked down almost every tree within 10 km of the central crater. Massive avalanches and mudflows, generated by the near-instantaneous melting of deep snowpacks on the flanks of the mountain, devastated an area more than 20 km to the north and east of the former summit, and rivers choked with all sorts of debris were flooded more than 100 km away. The area of almost total destruction was about 600 sq. km. Ash from the eruption cloud was rapidly blown to the northeast and east producing lightning which started many small forest fires. An erie darkness caused by the cloud enveloped the landscape more than 200 km from the blast area, and ash

  11. Dendrogeomorphic reconstruction of lahar activity and triggers: Shiveluch volcano, Kamchatka Peninsula, Russia

    NASA Astrophysics Data System (ADS)

    Salaorni, E.; Stoffel, M.; Tutubalina, O.; Chernomorets, S.; Seynova, I.; Sorg, A.

    2017-01-01

    Lahars are highly concentrated, water-saturated volcanic hyperconcentrated flows or debris flows containing pyroclastic material and are a characteristic mass movement process on volcanic slopes. On Kamchatka Peninsula (Russian Federation), lahars are widespread and may affect remote settlements. Historical records of past lahar occurrences are generally sparse and mostly limited to events which damaged infrastructure on the slopes or at the foot of volcanoes. In this study, we present a tree-ring-based reconstruction of spatiotemporal patterns of past lahar activity at Shiveluch volcano. Using increment cores and cross sections from 126 Larix cajanderi trees, we document 34 events covering the period AD 1729-2012. Analyses of the seasonality of damage in trees reveal that 95% of all lahars occurred between October and May and thus point to the predominant role of the sudden melt of the snow cover by volcanic material. These observations suggest that most lahars were likely syn-eruptive and that lahar activity is largely restricted to periods of volcanic activity. By contrast, rainfall events do not seem to play a significant role in lahar triggering.

  12. Ultra-high Resolution Mapping of the Inner Crater of the Active Kick'em Jenny Volcano

    NASA Astrophysics Data System (ADS)

    Hart, L.; Scott, C.; Tominaga, M.; Smart, C.; Vaughn, I.; Roman, C.; Carey, S.; German, C. R.; Participants, T.

    2015-12-01

    We conducted high-resolution geological characterization of a 0.015km^2 region of the inner crater of the most active submarine volcano in the Caribbean, Kick'em Jenny, located 8 km off Grenada in the Lesser Antilles Island Arc. We obtained digital still images and microbathymetery at an altitude of 3 m from the seafloor by using stereo cameras and a BlueView system mounted on Remotely Operated Vehicle (ROV) Hercules during the NA054 cruise on E/V Nautilus (Sept. - Oct. 2014). The seafloor images were processed to construct 2-D photo mosaics of the survey area using Standard Hercules Imaging Suite. We systematically classified the photographed seafloor geology based on the distribution of seafloor morphology and the observable rock fragment and outcrop sizes. The center of the crater floor shows a smooth, coherent texture with little variation in sea floor morphology. From immediately outside this area toward the crater rim, we observe an extensive area covered with outcrops, small rocks, and sediment: and within this area, (1) the north section is partially covered by uneven outcrops with elongated lineaments and a course, rugged seafloor with individual rock fragments observable; (2) the middle section contains high variability and heterogeneity in seafloor morphology in a non-systematic manner; and (3) overall, the southern most section displays subdued seafloor features both in space and variability compared to the other areas. The distributions of rock fragments were classified into four distinct sizes. We observe: (i) little variation in size distribution near the center of the crater floor; and (ii) rock fragment size increasing toward the rim of the crater. To obtain a better understanding of the link between variation in seafloor morphology, rock size distribution, and other in situ processes, we compare our observations on the digital photo mosaic to bathymetry data and ROV visuals (e.g. vents and bacterial mats).

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

    PubMed Central

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

    2006-01-01

    Submersible exploration of the Samoan hotspot revealed a new, 300-m-tall, volcanic cone, named Nafanua, in the summit crater of Vailulu’u seamount. Nafanua grew from the 1,000-m-deep crater floor in <4 years and could reach the sea surface within decades. Vents fill Vailulu’u crater with a thick suspension of particulates and apparently toxic fluids that mix with seawater entering from the crater breaches. Low-temperature vents form Fe oxide chimneys in many locations and up to 1-m-thick layers of hydrothermal Fe floc on Nafanua. High-temperature (81°C) hydrothermal vents in the northern moat (945-m water depth) produce acidic fluids (pH 2.7) with rising droplets of (probably) liquid CO2. The Nafanua summit vent area is inhabited by a thriving population of eels (Dysommina rugosa) that feed on midwater shrimp probably concentrated by anticyclonic currents at the volcano summit and rim. The moat and crater floor around the new volcano are littered with dead metazoans that apparently died from exposure to hydrothermal emissions. Acid-tolerant polychaetes (Polynoidae) live in this environment, apparently feeding on bacteria from decaying fish carcasses. Vailulu’u is an unpredictable and very active underwater volcano presenting a potential long-term volcanic hazard. Although eels thrive in hydrothermal vents at the summit of Nafanua, venting elsewhere in the crater causes mass mortality. Paradoxically, the same anticyclonic currents that deliver food to the eels may also concentrate a wide variety of nektonic animals in a death trap of toxic hydrothermal fluids. PMID:16614067

  14. Acoustic Recordings of Strombolian and Subplinian Activity at Shishaldin Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Caplan-Auerbach, J.; McNutt, S. R.; Vergniolle, S.; Boichu, M.

    2002-05-01

    New data from a pressure sensor provide a detailed perspective on the 1999 eruption of Shishaldin volcano, Alaska. The eruption was well monitored by a 6-station seismic network and frequent satellite passes, but visual observations were minimal. To refine our interpretation of the 1999 eruption we investigate acoustic data recorded on a pressure sensor 6.5 km north of Shishaldin. Three types of acoustic signals were identified, representing different types of eruptive behavior. On April 19, 1999 the pressure sensor recorded a monotonic (2-3 Hz) hum that grew in amplitude for more than 13 hours. At 19:35 UTC on April 19, the humming signal abruptly ended and seismic tremor amplitude increased dramatically. Four minutes later, a broadband (1-15 Hz) signal was recorded on both the pressure sensor and the seismometers, suggesting the onset of the main Subplinian phase. The Subplinian phase appears in the acoustic record as a 50-min broadband signal, over which several low-frequency bursts are superimposed. The final acoustic phase detected by the pressure sensor was a series of discrete pulses, interpreted to be strong Strombolian gas explosions. The strongest explosions, recorded on April 23rd were associated with a small, ash-poor plume and strong seismic tremor. In time series, these events are similar to gas explosions observed at other volcanoes such as Stromboli and Karymsky, but are of lower frequency (1-2 Hz) and are 1-2 orders of magnitude (up to 60 Pa at 6.5 km) larger. Waveform modeling allows us to constrain the size and overpressure of the bubbles, as well as the amount of gas and magma released during the Strombolian phase of the eruption. The acoustic data may be used to investigate the change from Strombolian activity to Subplinian, and back to Strombolian. The 1999 Shishaldin eruption shows that pressure sensors can serve as an excellent complement to traditional means of monitoring remote volcanoes.

  15. Origin and distribution of thiophenes and furans in gas discharges from active volcanoes and geothermal systems.

    PubMed

    Tassi, Franco; Montegrossi, Giordano; Capecchiacci, Francesco; Vaselli, Orlando

    2010-03-31

    The composition of non-methane organic volatile compounds (VOCs) determined in 139 thermal gas discharges from 18 different geothermal and volcanic systems in Italy and Latin America, consists of C(2)-C(20) species pertaining to the alkanes, alkenes, aromatics and O-, S- and N-bearing classes of compounds. Thiophenes and mono-aromatics, especially the methylated species, are strongly enriched in fluids emissions related to hydrothermal systems. Addition of hydrogen sulphide to dienes and electrophilic methylation involving halogenated radicals may be invoked for the formation of these species. On the contrary, the formation of furans, with the only exception of C(4)H(8)O, seems to be favoured at oxidizing conditions and relatively high temperatures, although mechanisms similar to those hypothesized for the production of thiophenes can be suggested. Such thermodynamic features are typical of fluid reservoirs feeding high-temperature thermal discharges of volcanoes characterised by strong degassing activity, which are likely affected by conspicuous contribution from a magmatic source. The composition of heteroaromatics in fluids naturally discharged from active volcanoes and geothermal areas can then be considered largely dependent on the interplay between hydrothermal vs. magmatic contributions. This implies that they can be used as useful geochemical tools to be successfully applied in both volcanic monitoring and geothermal prospection.

  16. Development of an automatic volcanic ash sampling apparatus for active volcanoes

    NASA Astrophysics Data System (ADS)

    Shimano, Taketo; Nishimura, Takeshi; Chiga, Nobuyuki; Shibasaki, Yoshinobu; Iguchi, Masato; Miki, Daisuke; Yokoo, Akihiko

    2013-12-01

    We develop an automatic system for the sampling of ash fall particles, to be used for continuous monitoring of magma ascent and eruptive dynamics at active volcanoes. The system consists of a sampling apparatus and cameras to monitor surface phenomena during eruptions. The Sampling Apparatus for Time Series Unmanned Monitoring of Ash (SATSUMA-I and SATSUMA-II) is less than 10 kg in weight and works automatically for more than a month with a 10-kg lead battery to obtain a total of 30 to 36 samples in one cycle of operation. The time range covered in one cycle varies from less than an hour to several months, depending on the aims of observation, allowing researchers to target minute-scale fluctuations in a single eruptive event, as well as daily to weekly trends in persistent volcanic activity. The latest version, SATSUMA-II, also enables control of sampling parameters remotely by e-mail commands. Durability of the apparatus is high: our prototypes worked for several months, in rainy and typhoon seasons, at windy and humid locations, and under strong sunlight. We have been successful in collecting ash samples emitted from Showa crater almost everyday for more than 4 years (2008-2012) at Sakurajima volcano in southwest Japan.

  17. Relationship between fumarole gas composition and eruptive activity at Galeras Volcano, Colombia

    SciTech Connect

    Fischer, T.P.; Williams, S.N.; Arehart, G.B.; Sturchio, N.C.

    1996-06-01

    Forecasting volcanic eruptions is critical to the mitigation of hazards for the millions of people living dangerously close to active volcanoes. Volcanic gases collected over five years from Galeras Volcano, Colombia, and analyzed for chemical and isotopic composition show the effects of long-term degassing of the magma body and a gradual decline in sulfur content of the gases. In contrast, short-term (weeks), sharp variations are the precursors to explosive eruptions. Selective absorption of magmatic SO{sub 2} and HCl due to interaction with low-temperature geothermal waters allows the gas emissions to become dominated by CO{sub 2}. Absorption appears to precede an eruption because magmatic volatiles are slowed or retained by a sealing carapace, reducing the total flux of volatiles and allowing the hydrothermal volatiles to dominate gas emissions. Temporal changes in gas compositions were correlated with eruptive activity and provide new evidence bearing on the mechanism of this type of `pneumatic` explosive eruptions. 18 refs., 5 figs.

  18. Carbonado-like diamond from the Avacha active volcano in Kamchatka, Russia

    NASA Astrophysics Data System (ADS)

    Kaminsky, Felix V.; Wirth, Richard; Anikin, Leonid P.; Morales, Luiz; Schreiber, Anja

    2016-11-01

    In addition to a series of finds of diamond in mafic volcanic and ultramafic massive rocks in Kamchatka, Russia, a carbonado-like diamond aggregate was identified in recent lavas of the active Avacha volcano. This aggregate differs from 'classic carbonado' by its location within an active volcanic arc, well-formed diamond crystallites, and cementing by Si-containing aggregates rather than sintering. The carbonado-like aggregate contains inclusions of Mn-Ni-Si-Fe alloys, native β-Mn, tungsten and boron carbides, which are uncommon for both carbonado and monocrystalline diamonds. Mn-Ni-Si-Fe alloys, trigonal W2C and trigonal B4C are new mineral species that were not previously found in the natural environment. The formation of the carbonado-like diamond aggregate started with formation at 850-1000 °C of tungsten and boron carbides, Mn-Ni-Si-Fe alloys and native β-Mn, which were used as seeds for the subsequent crystallization of micro-sized diamond aggregate. In the final stage, the diamond aggregate was cemented by amorphous silica, tridymite, β-SiC, and native silicon. The carbonado-like aggregate was most likely formed at near-atmospheric pressure conditions via the CVD mechanism during the course or shortly after one of the volcanic eruption pulses of the Avacha volcano. Volcanic gases played a great role in the formation of the carbonado-like aggregate.

  19. Origin and Distribution of Thiophenes and Furans in Gas Discharges from Active Volcanoes and Geothermal Systems

    PubMed Central

    Tassi, Franco; Montegrossi, Giordano; Capecchiacci, Francesco; Vaselli, Orlando

    2010-01-01

    The composition of non-methane organic volatile compounds (VOCs) determined in 139 thermal gas discharges from 18 different geothermal and volcanic systems in Italy and Latin America, consists of C2–C20 species pertaining to the alkanes, alkenes, aromatics and O-, S- and N-bearing classes of compounds. Thiophenes and mono-aromatics, especially the methylated species, are strongly enriched in fluids emissions related to hydrothermal systems. Addition of hydrogen sulphide to dienes and electrophilic methylation involving halogenated radicals may be invoked for the formation of these species. On the contrary, the formation of furans, with the only exception of C4H8O, seems to be favoured at oxidizing conditions and relatively high temperatures, although mechanisms similar to those hypothesized for the production of thiophenes can be suggested. Such thermodynamic features are typical of fluid reservoirs feeding high-temperature thermal discharges of volcanoes characterised by strong degassing activity, which are likely affected by conspicuous contribution from a magmatic source. The composition of heteroaromatics in fluids naturally discharged from active volcanoes and geothermal areas can then be considered largely dependent on the interplay between hydrothermal vs. magmatic contributions. This implies that they can be used as useful geochemical tools to be successfully applied in both volcanic monitoring and geothermal prospection. PMID:20480029

  20. Monitoring Monitoring Evolving Activity at Popocatepetl Volcano, Mexico, 2000-2001

    NASA Astrophysics Data System (ADS)

    Martin-DelPozzo, A.; Aceves, F.; Bonifaz, R.; Humberto, S.

    2001-12-01

    After 6 years of small eruptions, activity at Mexico's 5,452m high Popocatepetl Volcano in central Mexico, peaked in the December 2000-January 2001 eruptions. Precursors included an important increase in seismicity as well as in magmatic components of spring water and small scale deformation which resulted in growth of a new crater dome from January 16 on. Evacuation of the towns nearest the volcano over Christmas was decided because of the possibility of pyroclastic flows. During the previous years, crater dome growth, contraction and explosive clearing has dominated the activity. The January 22 eruption produced an eruption column approximately 17km high with associated pyroclastic flows. Ejecta was composed of both basic and evolved scoria and pumice and dome lithics. A large proportion of the juvenile material was intermediate between these 2 endmenbers (59-63percent SiO2 and 3.5 to 5.5 MgO) consistent with a small basic pulse entering a more evolved larger batch of magma. The January eruption left a large pit which has been partially infilled by another crater dome this August 2001.

  1. How caldera collapse shapes the shallow emplacement and transfer of magma in active volcanoes

    NASA Astrophysics Data System (ADS)

    Corbi, F.; Rivalta, E.; Pinel, V.; Maccaferri, F.; Bagnardi, M.; Acocella, V.

    2015-12-01

    Calderas are topographic depressions formed by the collapse of a partly drained magma reservoir. At volcanic edifices with calderas, eruptive fissures can circumscribe the outer caldera rim, be oriented radially and/or align with the regional tectonic stress field. Constraining the mechanisms that govern this spatial arrangement is fundamental to understand the dynamics of shallow magma storage and transport and evaluate volcanic hazard. Here we show with numerical models that the previously unappreciated unloading effect of caldera formation may contribute significantly to the stress budget of a volcano. We first test this hypothesis against the ideal case of Fernandina, Galápagos, where previous models only partly explained the peculiar pattern of circumferential and radial eruptive fissures and the geometry of the intrusions determined by inverting the deformation data. We show that by taking into account the decompression due to the caldera formation, the modeled edifice stress field is consistent with all the observations. We then develop a general model for the stress state at volcanic edifices with calderas based on the competition of caldera decompression, magma buoyancy forces and tectonic stresses. These factors control: 1) the shallow accumulation of magma in stacked sills, consistently with observations; 2) the conditions for the development of circumferential and/or radial eruptive fissures, as observed on active volcanoes. This top-down control exerted by changes in the distribution of mass at the surface allows better understanding of how shallow magma is transferred at active calderas, contributing to forecasting the location and type of opening fissures.

  2. Seismic image of a CO2 reservoir beneath a seismically active volcano

    USGS Publications Warehouse

    Julian, B.R.; Pitt, A.M.; Foulger, G.R.

    1998-01-01

    Mammoth Mountain is a seismically active volcano 200 000 to 50 000 years old, situated on the southwestern rim of Long Valley caldera, California. Since 1989 it has shown evidence of unrest in the form of earthquake swarms (Hill et al. 1990), volcanic 'long-period' earthquakes (Pitt and Hill 1994), increased output of magmatic 3He (Sorey et al. 1993) and the emission of about 500 tonnes day-1 of CO2 (Farrar et al. 1995; Hill 1996; M. Sorey, personal communication, 1997) which has killed trees and poses a threat to human safety. Local-earthquake tomography shows that in mid-1989 areas of subsequent tree-kill were underlain by extensive regions where the ratio of the compressional and shear elastic-wave speeds Vp/VS was about 9% lower than in the surrounding rocks. Theory (Mavko and Mukerji 1995), experiment (Ito, DeVilbiss and Nur 1979) and experience at other geothermal/volcanic areas (Julian et al. 1996) and at petroleum reservoirs (Harris et al. 1996) indicate that Vp/VS is sensitive to pore-fluid compressibility, through its effect on Vp. The observed Vp/VS anomaly is probably caused directly by CO2, and seismic Vp/VS tomography is thus a promising tool for monitoring gas concentration and movement in volcanoes, which may in turn be related to volcanic activity.

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

    NASA Astrophysics Data System (ADS)

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

    2009-05-01

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

  4. Indigenous Uses and Pharmacological Activity of Traditional Medicinal Plants in Mount Taibai, China

    PubMed Central

    Chang, Na; Luo, Ziwen; Song, Huiying

    2017-01-01

    This study was carried out to investigate the indigenous use and pharmacological activity of traditional medicinal plants of Mount Taibai, China. Pharmacological data were collected by conducting informal interviews with local experienced doctors practicing traditional Chinese medicine and via open-ended questionnaires on villagers. We conclude that the residents of Mt. Taibai possess rich pharmacological knowledge. This study may help identify high-value traditional medicinal plant species, promote economic development associated with local medicinal plants, and increase awareness from government departments. PMID:28303162

  5. Santorini Volcano

    USGS Publications Warehouse

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

    1999-01-01

    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.

  6. The structure of the Campanian Plain and the activity of the Neapolitan volcanoes (Italy)

    NASA Astrophysics Data System (ADS)

    Scandone, Roberto; Bellucci, Francesca; Lirer, Lucio; Rolandi, Giuseppe

    1991-08-01

    The central Campanian Plain is dominated by the structural depression of Acerra whose origin is tectonic, but may have been enlarged and further depressed after the eruption of the Campanian Ignimbrite (42-25 ka). The deposits of the Campanian Ignimbrite are possibly the results of multiple eruptions with huge pyroclastic deposits that covered all the Campanian Plain. The more recent activity of Vesuvius, Campi Flegrei and Procida occurred on the borders of Acerra depression and resulted from a reactivation of regional faults after the Campanian Ignimbrite cycle. The activity of Vesuvius produced the building of a stratovolcano mostly by effusive and plinian explosive eruptions. The Campi Flegrei area, on the contrary, was dominated by the eruption of the Neapolitan Yellow Tuff at 12 ka that produced a caldera collapse of the Gulf of Pozzuoli. The caldera formation controlled the emplacement of the recent activity of Campi Flegrei and the new volcanoes were formed only within the caldera or along its rim.

  7. Deep structure and volcanic activity of Mount Elbrus and a portion of the Elbrus-Tyrnyauz valley: Geological and geophysical data

    NASA Astrophysics Data System (ADS)

    Rogozhin, E. A.; Gorbatikov, A. V.; Kharazova, Yu. V.; Stepanova, M. Yu.; Nikolaev, A. V.

    2016-11-01

    A microseismic sounding profile was made along the Baksan River valley from the eastern summit of Elbrus volcano to the southern edge of town Tyrnyauz. The geological section along the profile presents the structural features of the subaerial structure of Mount Elbrus and magmatic chambers, which are traced to a depth of 40 km or more as a subvertical chain. Along the profile, deep-seated faults, well correlated with their morphological manifestations on the surface, were identified. Under the southern edge of town Tyrnyauz, a low-velocity region, comparable in size to Elbrus volcano, was interpreted as the cooling volcanic structure. The results obtained were correlated with the data available on the geology and geomorphology of the area of study, as well as data obtained earlier during independent studies of Elbrus volcano.

  8. Overview of the 2004 to 2006, and continuing, eruption of Mount St. Helens, Washington: Chapter 1 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Scott, William E.; Sherrod, David R.; Gardner, Cynthia A.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    Rapid onset of unrest at Mount St. Helens on September 23, 2004, initiated an uninterrupted lava-dome-building eruption that continues to the time of writing this overview (spring 2006) for a volume of papers focused on this eruption. About three weeks of intense seismic unrest and localized surface uplift, punctuated by four brief explosions, constituted a ventclearing phase, during which there was a frenzy of media attention and considerable uncertainty regarding the likely course of the eruption. The third week exhibited lessened seismicity and only minor venting of steam and ash, but rapid growth of the uplift, or welt, south of the 1980-86 lava dome proceeded as magma continued to push upward. Crystalrich dacite (~65 weight percent SiO2) lava first appeared at the surface on October 11, 2004, beginning the growth of a complex lava dome of uniform chemical composition accompanied by persistent but low levels of seismicity, rare explosions, low gas emissions, and frequent rockfalls. Petrologic studies suggest that the dome lava is chiefly of 1980s vintage, but with an admixed portion of new dacite. Alternatively, it may derive from a part of the magma chamber not tapped by 1980s eruptions. Regardless, detailed investigations of crystal chemistry, melt inclusions, and isotopes reveal a complex magmatic history. Largely episodic extrusion between 1980 and 1986 produced a relatively symmetrical lava dome composed of stubby lobes. In contrast, continuous extrusion at mean rates of about 5 m3/s in autumn 2004 to 3/s in early 2006 has produced an east-west ridge of three mounds with total volume about equal to that of the old dome. During much of late 2004 to summer 2005, a succession of spines, two recumbent and one steeply sloping and each mantled by striated gouge, grew to nearly 500 m in length in the southeastern sector of the 1980 crater and later disintegrated into two mounds. Since then, growth has been concentrated in the southwestern sector, producing a

  9. Recent uplift and hydrothermal activity at Tangkuban Parahu volcano, west Java, Indonesia

    USGS Publications Warehouse

    Dvorak, J.; Matahelumual, J.; Okamura, A.T.; Said, H.; Casadevall, T.J.; Mulyadi, D.

    1990-01-01

    Tangkuban Parahu is an active stratovolcano located 17 km north of the city of Bandung in the province west Java, Indonesia. All historical eruptive activity at this volcano has been confined to a complex of explosive summit craters. About a dozen eruptions-mostly phreatic events- and 15 other periods of unrest, indicated by earthquakes or increased thermal activity, have been noted since 1829. The last magmatic eruption occurred in 1910. In late 1983, several small phreatic explosions originated from one of the summit craters. More recently, increased hydrothermal and earthquake activity occurred from late 1985 through 1986. Tilt measurements, using a spirit-level technique, have been made every few months since February 1981 in the summit region and along the south and east flanks of the volcano. Measurements made in the summit region indicated uplift since the start of these measurements through at least 1986. From 1981 to 1983, the average tilt rate at the edges of the summit craters was 40-50 microradians per year. After the 1983 phreatic activity, the tilt rate decreased by about a factor of five. Trilateration surveys across the summit craters and on the east flank of the volcano were conducted in 1983 and 1986. Most line length changes measured during this three-year period did not exceed the expected uncertainty of the technique (4 ppm). The lack of measurable horizontal strain across the summit craters seems to contradict the several years of tilt measurements. Using a point source of dilation in an elastic half-space to model tilt measurements, the pressure center at Tangkuban Parahu is located about 1.5 km beneath the southern part of the summit craters. This is beneath the epicentral area of an earthquake swarm that occurred in late 1983. The average rate in the volume of uplift from 1981 to 1983 was 3 million m3 per year; from 1983 to 1986 it averaged about 0.4 million m3 per year. Possible causes for this uplift are increased pressure within a very

  10. Social studies of volcanology: knowledge generation and expert advice on active volcanoes

    NASA Astrophysics Data System (ADS)

    Donovan, Amy; Oppenheimer, Clive; Bravo, Michael

    2012-04-01

    This paper examines the philosophy and evolution of volcanological science in recent years, particularly in relation to the growth of volcanic hazard and risk science. It uses the lens of Science and Technology Studies to examine the ways in which knowledge generation is controlled and directed by social forces, particularly during eruptions, which constitute landmarks in the development of new technologies and models. It also presents data from a survey of volcanologists carried out during late 2008 and early 2009. These data concern the felt purpose of the science according to the volcanologists who participated and their impressions of the most important eruptions in historical time. It demonstrates that volcanologists are motivated both by the academic science environment and by a social concern for managing the impact of volcanic hazards on populations. Also discussed are the eruptions that have most influenced the discipline and the role of scientists in policymaking on active volcanoes. Expertise in volcanology can become the primary driver of public policy very suddenly when a volcano erupts, placing immense pressure on volcanologists. In response, the epistemological foundations of volcanology are on the move, with an increasing volume of research into risk assessment and management. This requires new, integrated methodologies for knowledge collection that transcend scientific disciplinary boundaries.

  11. Fiber Bragg grating strain sensors to monitor and study active volcanoes

    NASA Astrophysics Data System (ADS)

    Sorrentino, Fiodor; Beverini, Nicolò; Carbone, Daniele; Carelli, Giorgio; Francesconi, Francesco; Gambino, Salvo; Giacomelli, Umberto; Grassi, Renzo; Maccioni, Enrico; Morganti, Mauro

    2016-04-01

    Stress and strain changes are among the best indicators of impending volcanic activity. In volcano geodesy, borehole volumetric strain-meters are mostly utilized. However, they are not easy to install and involve high implementation costs. Advancements in opto-electronics have allowed the development of low-cost sensors, reliable, rugged and compact, thus particularly suitable for field application. In the framework of the EC FP7 MED-SUV project, we have developed strain sensors based on the fiber Bragg grating (FBG) technology. In comparison with previous implementation of the FBG technology to study rock deformations, we have designed a system that is expected to offer a significantly higher resolution and accuracy in static measurements and a smooth dynamic response up to 100 Hz, implying the possibility to observe seismic waves. The system performances are tailored to suit the requirements of volcano monitoring, with special attention to power consumption and to the trade-off between performance and cost. Preliminary field campaigns were carried out on Mt. Etna (Italy) using a prototypal single-axis FBG strain sensor, to check the system performances in out-of-the-lab conditions and in the harsh volcanic environment (lack of mains electricity for power, strong diurnal temperature changes, strong wind, erosive ash, snow and ice during the winter time). We also designed and built a FBG strain sensor featuring a multi-axial configuration which was tested and calibrated in the laboratory. This instrument is suitable for borehole installation and will be tested on Etna soon.

  12. Vein networks in hydrothermal systems provide constraints for the monitoring of active volcanoes.

    PubMed

    Cucci, Luigi; Di Luccio, Francesca; Esposito, Alessandra; Ventura, Guido

    2017-12-01

    Vein networks affect the hydrothermal systems of many volcanoes, and variations in their arrangement may precede hydrothermal and volcanic eruptions. However, the long-term evolution of vein networks is often unknown because data are lacking. We analyze two gypsum-filled vein networks affecting the hydrothermal field of the active Lipari volcanic Island (Italy) to reconstruct the dynamics of the hydrothermal processes. The older network (E1) consists of sub-vertical, N-S striking veins; the younger network (E2) consists of veins without a preferred strike and dip. E2 veins have larger aperture/length, fracture density, dilatancy, and finite extension than E1. The fluid overpressure of E2 is larger than that of E1 veins, whereas the hydraulic conductance is lower. The larger number of fracture intersections in E2 slows down the fluid movement, and favors fluid interference effects and pressurization. Depths of the E1 and E2 hydrothermal sources are 0.8 km and 4.6 km, respectively. The decrease in the fluid flux, depth of the hydrothermal source, and the pressurization increase in E2 are likely associated to a magma reservoir. The decrease of fluid discharge in hydrothermal fields may reflect pressurization at depth potentially preceding hydrothermal explosions. This has significant implications for the long-term monitoring strategy of volcanoes.

  13. Capturing the fingerprint of Etna volcano activity in gravity and satellite radar data

    PubMed Central

    Negro, Ciro Del; Currenti, Gilda; Solaro, Giuseppe; Greco, Filippo; Pepe, Antonio; Napoli, Rosalba; Pepe, Susi; Casu, Francesco; Sansosti, Eugenio

    2013-01-01

    Long-term and high temporal resolution gravity and deformation data move us toward a better understanding of the behavior of Mt Etna during the June 1995 – December 2011 period in which the volcano exhibited magma charging phases, flank eruptions and summit crater activity. Monthly repeated gravity measurements were coupled with deformation time series using the Differential Synthetic Aperture Radar Interferometry (DInSAR) technique on two sequences of interferograms from ERS/ENVISAT and COSMO-SkyMed satellites. Combining spatiotemporal gravity and DInSAR observations provides the signature of three underlying processes at Etna: (i) magma accumulation in intermediate storage zones, (ii) magmatic intrusions at shallow depth in the South Rift area, and (iii) the seaward sliding of the volcano's eastern flank. Here we demonstrate the strength of the complementary gravity and DInSAR analysis in discerning among different processes and, thus, in detecting deep magma uprising in months to years before the onset of a new Etna eruption. PMID:24169569

  14. Kolumbo submarine volcano (Greece): An active window into the Aegean subduction system.

    PubMed

    Rizzo, Andrea Luca; Caracausi, Antonio; Chavagnac, Valèrie; Nomikou, Paraskevi; Polymenakou, Paraskevi N; Mandalakis, Manolis; Kotoulas, Georgios; Magoulas, Antonios; Castillo, Alain; Lampridou, Danai

    2016-06-17

    Submarine volcanism represents ~80% of the volcanic activity on Earth and is an important source of mantle-derived gases. These gases are of basic importance for the comprehension of mantle characteristics in areas where subaerial volcanism is missing or strongly modified by the presence of crustal/atmospheric components. Though, the study of submarine volcanism remains a challenge due to their hazardousness and sea-depth. Here, we report (3)He/(4)He measurements in CO2-dominated gases discharged at 500 m below sea level from the high-temperature (~220 °C) hydrothermal system of the Kolumbo submarine volcano (Greece), located 7 km northeast off Santorini Island in the central part of the Hellenic Volcanic Arc (HVA). We highlight that the mantle below Kolumbo and Santorini has a (3)He/(4)He signature of at least 7.0 Ra (being Ra the (3)He/(4)He ratio of atmospheric He equal to 1.39×10(-6)), 3 Ra units higher than actually known for gases-rocks from Santorini. This ratio is also the highest measured across the HVA and is indicative of the direct degassing of a Mid-Ocean-Ridge-Basalts (MORB)-like mantle through lithospheric faults. We finally highlight that the degassing of high-temperature fluids with a MORB-like (3)He/(4)He ratio corroborates a vigorous outgassing of mantle-derived volatiles with potential hazard at the Kolumbo submarine volcano.

  15. High-resolution seismic structure analysis of an active submarine mud volcano area off SW Taiwan

    NASA Astrophysics Data System (ADS)

    Lin, Hsiao-Shan; Hsu, Shu-Kun; Tsai, Wan-Lin; Tsai, Ching-Hui; Lin, Shin-Yi; Chen, Song-Chuen

    2015-04-01

    In order to better understand the subsurface structure related to an active mud volcano MV1 and to understand their relationship with gas hydrate/cold seep formation, we conducted deep-towed side-scan sonar (SSS), sub-bottom profiler (SBP), multibeam echo sounding (MBES), and multi-channel reflection seismic (MCS) surveys off SW Taiwan from 2009 to 2011. As shown in the high-resolution sub-bottom profiler and EK500 sonar data, the detailed structures reveal more gas seeps and gas flares in the study area. In addition, the survey profiles show several submarine landslides occurred near the thrust faults. Based on the MCS results, we can find that the MV1 is located on top of a mud diapiric structure. It indicates that the MV1 has the same source as the associated mud diapir. The blanking of the seismic signal may indicate the conduit for the upward migration of the gas (methane or CO2). Therefore, we suggest that the submarine mud volcano could be due to a deep source of mud compressed by the tectonic convergence. Fluids and argillaceous materials have thus migrated upward along structural faults and reach the seafloor. The gas-charged sediments or gas seeps in sediments thus make the seafloor instable and may trigger submarine landslides.

  16. Kolumbo submarine volcano (Greece): An active window into the Aegean subduction system

    PubMed Central

    Rizzo, Andrea Luca; Caracausi, Antonio; Chavagnac, Valèrie; Nomikou, Paraskevi; Polymenakou, Paraskevi N.; Mandalakis, Manolis; Kotoulas, Georgios; Magoulas, Antonios; Castillo, Alain; Lampridou, Danai

    2016-01-01

    Submarine volcanism represents ~80% of the volcanic activity on Earth and is an important source of mantle-derived gases. These gases are of basic importance for the comprehension of mantle characteristics in areas where subaerial volcanism is missing or strongly modified by the presence of crustal/atmospheric components. Though, the study of submarine volcanism remains a challenge due to their hazardousness and sea-depth. Here, we report 3He/4He measurements in CO2–dominated gases discharged at 500 m below sea level from the high-temperature (~220 °C) hydrothermal system of the Kolumbo submarine volcano (Greece), located 7 km northeast off Santorini Island in the central part of the Hellenic Volcanic Arc (HVA). We highlight that the mantle below Kolumbo and Santorini has a 3He/4He signature of at least 7.0 Ra (being Ra the 3He/4He ratio of atmospheric He equal to 1.39×10−6), 3 Ra units higher than actually known for gases-rocks from Santorini. This ratio is also the highest measured across the HVA and is indicative of the direct degassing of a Mid-Ocean-Ridge-Basalts (MORB)-like mantle through lithospheric faults. We finally highlight that the degassing of high-temperature fluids with a MORB-like 3He/4He ratio corroborates a vigorous outgassing of mantle-derived volatiles with potential hazard at the Kolumbo submarine volcano. PMID:27311383

  17. Kolumbo submarine volcano (Greece): An active window into the Aegean subduction system

    NASA Astrophysics Data System (ADS)

    Rizzo, Andrea Luca; Caracausi, Antonio; Chavagnac, Valèrie; Nomikou, Paraskevi; Polymenakou, Paraskevi N.; Mandalakis, Manolis; Kotoulas, Georgios; Magoulas, Antonios; Castillo, Alain; Lampridou, Danai

    2016-06-01

    Submarine volcanism represents ~80% of the volcanic activity on Earth and is an important source of mantle-derived gases. These gases are of basic importance for the comprehension of mantle characteristics in areas where subaerial volcanism is missing or strongly modified by the presence of crustal/atmospheric components. Though, the study of submarine volcanism remains a challenge due to their hazardousness and sea-depth. Here, we report 3He/4He measurements in CO2–dominated gases discharged at 500 m below sea level from the high-temperature (~220 °C) hydrothermal system of the Kolumbo submarine volcano (Greece), located 7 km northeast off Santorini Island in the central part of the Hellenic Volcanic Arc (HVA). We highlight that the mantle below Kolumbo and Santorini has a 3He/4He signature of at least 7.0 Ra (being Ra the 3He/4He ratio of atmospheric He equal to 1.39×10‑6), 3 Ra units higher than actually known for gases-rocks from Santorini. This ratio is also the highest measured across the HVA and is indicative of the direct degassing of a Mid-Ocean-Ridge-Basalts (MORB)-like mantle through lithospheric faults. We finally highlight that the degassing of high-temperature fluids with a MORB-like 3He/4He ratio corroborates a vigorous outgassing of mantle-derived volatiles with potential hazard at the Kolumbo submarine volcano.

  18. Volcanic activity observed from continuous seismic records in the region of the Klyuchevskoy group of volcanoes

    NASA Astrophysics Data System (ADS)

    Shapiro, N.; Droznin, D.; Droznina, S.; Senyukov, S.; Chebrov, V.; Gordeev, E.; Frank, W.

    2014-12-01

    We analyze continuous seismic records from 18 permanent stations operated in vicinity of the Klyuchevskoy group of volcanos (Kamchatka, Russia) during the period between 2009 and 2014. We explore the stability of the inter-station cross-correlation to detect different periods of sustained emission from seismic energy. The main idea of this approach is that cross-correlation waveforms computed from a wavefield emitted by a seismic source from a fixed position remain stable during the period when this source is acting. The detected periods of seismic emission correspond to different episodes of activity of volcanoes: Klyuchevskoy, Tolbachik, Shiveluch, and Kizimen. For Klyuchevskoy and Tolbachik whose recent eruptions are mostly effusive, the detected seismic signals correspond to typical volcanic tremor, likely caused by degassing processes. For Shiveluch and Kizimen producing more silicic lavas, the observed seismic emission often consists of many repetitive long period (LP) seismic events that might be related to the extrusion of viscous magmas. We develop an approach for automatic detection of these individual LP events in order to characterize variations of their size and recurrence in time.

  19. Volcanic activity observed from continuous seismic records in the region of the Klyuchevskoy group of volcanoes

    NASA Astrophysics Data System (ADS)

    Shapiro, N.; Droznin, D.; Droznina, S.; Senyukov, S.; Chebrov, V.; Gordeev, E.; Frank, W.

    2015-12-01

    We analyze continuous seismic records from 18 permanent stations operated in vicinity of the Klyuchevskoy group of volcanos (Kamchatka, Russia) during the period between 2009 and 2014. We explore the stability of the inter-station cross-correlation to detect different periods of sustained emission from seismic energy. The main idea of this approach is that cross-correlation waveforms computed from a wavefield emitted by a seismic source from a fixed position remain stable during the period when this source is acting. The detected periods of seismic emission correspond to different episodes of activity of volcanoes: Klyuchevskoy, Tolbachik, Shiveluch, and Kizimen. For Klyuchevskoy and Tolbachik whose recent eruptions are mostly effusive, the detected seismic signals correspond to typical volcanic tremor, likely caused by degassing processes. For Shiveluch and Kizimen producing more silicic lavas, the observed seismic emission often consists of many repetitive long period (LP) seismic events that might be related to the extrusion of viscous magmas. We develop an approach for automatic detection of these individual LP events in order to characterize variations of their size and recurrence in time.

  20. Identification and evolution of the juvenile component in 2004-2005 Mount St. Helens ash: Chapter 29 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Rowe, Michael C.; Thornber, Carl R.; Kent, Adam J.R.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    Petrologic studies of volcanic ash are commonly used to identify juvenile volcanic material and observe changes in the composition and style of volcanic eruptions. During the 2004-5 eruption of Mount St. Helens, recognition of the juvenile component in ash produced by early phreatic explosions was complicated by the presence of a substantial proportion of 1980-86 lava-dome fragments and glassy tephra, in addition to older volcanic fragments possibly derived from crater debris. In this report, we correlate groundmass textures and compositions of glass, mafic phases, and feldspar from 2004-5 ash in an attempt to identify juvenile material in early phreatic explosions and to distinguish among the various processes that generate and distribute ash. We conclude that clean glass in the ash is derived mostly from nonjuvenile sources and is not particularly useful for identifying the proportion of juvenile material in ash samples. High Li contents (>30 μg/g) in feldspars provide a useful tracer for juvenile material and suggest an increase in the proportion of the juvenile component between October 1 and October 4, 2004, before the emergence of hot dacite on the surface of the crater on October 11, 2004. The presence of Li-rich feldspar out of equilibrium (based on Liplagioclase/melt partitioning) with groundmass and bulk dacite early in the eruption also suggests vapor enrichment in the initially erupted dacite. If an excess vapor phase was, indeed, present, it may have provided a catalyst to initiate the eruption. Textural and compositional comparisons between dome fault gouge and the ash produced by rockfalls, rock avalanches, and vent explosions indicate that the fault gouge is a likely source of ash particles for both types of events. Comparison of the ash from vent explosions and rockfalls suggests that the fault gouge and new dome were initially heterogeneous, containing a mixture of conduit and crater debris and juvenile material, but became increasingly

  1. Late Holocene phases of dome growth and Plinian activity at Guagua Pichincha volcano (Ecuador)

    NASA Astrophysics Data System (ADS)

    Robin, Claude; Samaniego, Pablo; Le Pennec, Jean-Luc; Mothes, Patricia; van der Plicht, Johannes

    2008-09-01

    Since the eruption which affected Quito in AD 1660, Guagua Pichincha has been considered a hazardous volcano. Based on field studies and twenty 14C dates, this paper discusses the eruptive activity of this volcano, especially that of the last 2000 years. Three major Plinian eruptions with substantial pumice discharge occurred in the 1st century, the 10th century, and in AD 1660. The ages of organic paleosols and charcoal from block-and-ash flow and fallout deposits indicate that these eruptions occurred near the end of 100 to 200 year-long cycles of discontinuous activity which was comprised of dome growth episodes and minor pumice fallouts. The first cycle took place from ~ AD 1 to 140. The second one developed during the 9th and 10th centuries, lasted 150-180 yr, and included the largest Plinian event, with a VEI of 5. The third, historic cycle, about 200 yr in duration, includes pyroclastic episodes around AD 1450 and AD 1500, explosive activity between AD 1566 and AD 1582, possible precursors of the 1660 eruption in the early decades of the 17th century, and finally the 1660 eruption (VEI 4). A fourth event probably occurred around AD 500, but its authenticity requires confirmation. The Plinian events occurred at the end of these cycles which were separated by repose periods of at least 300 yr. Older volcanic activity of similar type occurred between ~ 4000 and ~ 3000 yr BP. Because ash fallout and related mudflows represent a serious hazard for Quito's metropolitan area, the significance of the increasing phreatic activity observed from 1981 to 1998, and the 1999-2001 magmatic episode of dome growth and collapse are discussed. These probably represent a short step in a longer evolution which may result in a major Plinian event in the future decades or in the next century, comparable to that which occurred during the 1st, 10th, and 17th centuries.

  2. Turtles to Terabytes: The Ongoing Revolution in Volcano Geodesy

    NASA Astrophysics Data System (ADS)

    Dzurisin, D.

    2015-12-01

    Volcano geodesy is in the midst of a revolution. GPS and InSAR, together with extensive ground-based sensor networks, have enabled major advances in understanding how and why volcanoes deform. Surveying techniques that produced a few bytes of information per benchmark per year have been replaced by continuously operating deformation networks and imaging radar satellites that generate terabytes of data at resolutions unattainable only a few decades ago. These developments have enabled more detailed assessments of volcano hazards, more accurate forecasts of volcanic activity, and better insights into how volcanoes behave over a variety of spatial and temporal scales. Forty years ago, repeated leveling surveys showed that the floor of the Yellowstone caldera had risen more than 70 cm in the past 5 decades. Today a network of GPS stations tracks surface movements continuously with millimeter-scale accuracy and the entire deformation field is imaged frequently by a growing number of SAR satellites, revealing a far more complex style of deformation than was recognized previously. At Mount St. Helens, the 1980-1986 eruption taught us that a seemingly quiescent volcano can suddenly become overtly restless, and that accurate eruption predictions are possible at least in some limited circumstances given sufficient observations. The lessons were revisited during the volcano's 2004-2008 eruption, during which a new generation of geodetic sensors and methods detected a range of co-eruptive changes that enabled new insights into the volcano's magma storage and transport system. These examples highlight volcano deformation styles and scales that were unknown just a few decades ago but now have been revealed by a growing number of data types and modeling methods. The rapid evolution that volcano geodesy is currently experiencing provides an ongoing challenge for geodesists, while also demonstrating that geodetic unrest is common, widespread, and illuminating. Vive la révolution!

  3. Subglacial melting associated with activity at Bárdarbunga volcano, Iceland, explored using numerical reservoir simulations

    NASA Astrophysics Data System (ADS)

    Reynolds, Hannah I.; Gudmundsson, Magnús T.; Högnadóttir, Thórdís

    2015-04-01

    Increased seismic activity was observed within the caldera of Bárdarbunga, a central volcano beneath Vatnajökull glacier, on 16 August 2014. The seismicity traced the path of a lateral dyke, initially propagating to the south east of the volcano, before changing course and continuing beyond the northern extent of the glacier. A short fissure eruption occurred at the site of the Holuhraun lavas on 29 August, lasting for approximately 5 hours and producing less than 1 million cubic meters of lava, before recommencing in earnest on 31 August with the large effusive eruption, which is still ongoing at the time of writing. The glacier surface has been monitored aerially since the onset of heightened seismic activity, and the caldera and dyke propagation path surveyed using radar profiling. Ice cauldrons are shallow depressions which form on the glacier surface due to basal melting, as a manifestation of heat flux from below; the melting ice acts as a calorimeter, allowing estimations of heat flux magnitude to be made. Several cauldrons were observed outside the caldera, two to the south east of Bárdarbunga, and three located above the path of the dyke under the Dyngjujökull outlet glacier. The cauldrons range in volume from approximately 0.001 km3 to 0.02 km3. We present time series data of the development and evolution of these cauldrons, with estimates of the heat flux magnitudes involved. The nature of the heat source required to generate the aforementioned cauldrons is not obvious and two scenarios are explored: 1) small subglacial eruptions; or 2) increased geothermal activity induced by the dyke intrusion. We investigate these scenarios using analytical and finite element modelling, considering the surface heat flux produced, and timescales and spatial extent of associated surface anomalies. A range of permeabilities has been explored. It is found that an intrusion of a dyke or sill into rocks where the groundwater is near or at the boiling point curve can

  4. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2005

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Estes, Steve; McNutt, Stephen R.

    2006-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at historically active volcanoes in Alaska since 1988 (Figure 1). The primary objectives of the seismic program are the real-time seismic monitoring of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog presents calculated earthquake hypocenters and seismic phase arrival data, and details changes in the seismic monitoring program for the period January 1 through December 31, 2005.The AVO seismograph network was used to monitor the seismic activity at thirty-two volcanoes within Alaska in 2005 (Figure 1). The network was augmented by two new subnetworks to monitor the Semisopochnoi Island volcanoes and Little Sitkin Volcano. Seismicity at these volcanoes was still being studied at the end of 2005 and has not yet been added to the list of permanently monitored volcanoes in the AVO weekly update. Following an extended period of monitoring to determine the background seismicity at the Mount Peulik, Ukinrek Maars, and Korovin Volcano, formal monitoring of these volcanoes began in 2005. AVO located 9,012 earthquakes in 2005.Monitoring highlights in 2005 include: (1) seismicity at Mount Spurr remaining above background, starting in February 2004, through the end of the year and into 2006; (2) an increase in seismicity at Augustine Volcano starting in May 2005, and continuing through the end of the year into 2006; (3) volcanic tremor and seismicity related to low-level strombolian activity at Mount Veniaminof in January to March and September; and (4) a seismic swarm at Tanaga Volcano in October and November.This catalog includes: (1) descriptions and locations of seismic instrumentation deployed in the field in 2005; (2) a

  5. Volcanic hazards at Mount Rainier, Washington

    USGS Publications Warehouse

    Crandell, Dwight Raymond; Mullineaux, Donal Ray

    1967-01-01

    Mount Rainier is a large stratovolcano of andesitic rock in the Cascade Range of western Washington. Although the volcano as it now stands was almost completely formed before the last major glaciation, geologic formations record a variety of events that have occurred at the volcano in postglacial time. Repetition of some of these events today without warning would result in property damage and loss of life on a catastrophic scale. It is appropriate, therefore, to examine the extent, frequency, and apparent origin of these phenomena and to attempt to predict the effects on man of similar events in the future. The present report was prompted by a contrast that we noted during a study of surficial geologic deposits in Mount Rainier National Park, between the present tranquil landscape adjacent to the volcano and the violent events that shaped parts of that same landscape in the recent past. Natural catastrophes that have geologic causes - such as eruptions, landslides, earthquakes, and floods - all too often are disastrous primarily because man has not understood and made allowance for the geologic environment he occupies. Assessment of the potential hazards of a volcanic environment is especially difficult, for prediction of the time and kind of volcanic activity is still an imperfect art, even at active volcanoes whose behavior has been closely observed for many years. Qualified predictions, however, can be used to plan ways in which hazards to life and property can be minimized. The prediction of eruptions is handicapped because volcanism results from conditions far beneath the surface of the earth, where the causative factors cannot be seen and, for the most part, cannot be measured. Consequently, long-range predictions at Mount Rainier can be based only on the past behavior of the volcano, as revealed by study of the deposits that resulted from previous eruptions. Predictions of this sort, of course, cannot be specific as to time and locale of future events, and

  6. Dynamics of seismogenic volcanic extrusion resisted by a solid surface plug, Mount St. Helens, 2004-2005: Chapter 21 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Iverson, Richard M.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    The 2004-5 eruption of Mount St. Helens exhibited sustained, near-equilibrium behavior characterized by nearly steady extrusion of a solid dacite plug and nearly periodic occurrence of shallow earthquakes. Diverse data support the hypothesis that these earthquakes resulted from stick-slip motion along the margins of the plug as it was forced incrementally upward by ascending, solidifying, gas-poor magma. I formalize this hypothesis with a mathematical model derived by assuming that magma enters the base of the eruption conduit at a steady rate, invoking conservation of mass and momentum of the magma and plug, and postulating simple constitutive equations that describe magma and conduit compressibilities and friction along the plug margins. Reduction of the model equations reveals a strong mathematical analogy between the dynamics of the magma-plug system and those of a variably damped oscillator. Oscillations in extrusion velocity result from the interaction of plug inertia, a variable upward force due to magma pressure, and a downward force due to the plug weight. Damping of oscillations depends mostly on plug-boundary friction, and oscillations grow unstably if friction exhibits rate weakening similar to that observed in experiments. When growth of oscillations causes the extrusion rate to reach zero, however, gravity causes friction to reverse direction, and this reversal instigates a transition from unstable oscillations to self-regulating stick-slip cycles. The transition occurs irrespective of the details of rate-weakening behavior, and repetitive stick-slip cycles are, therefore, robust features of the system’s dynamics. The presence of a highly compressible elastic driving element (that is, magma containing bubbles) appears crucial for enabling seismogenic slip events to occur repeatedly at the shallow earthquake focal depths (8 N. These results imply that the system’s self-regulating behavior is not susceptible to dramatic change--provided that the

  7. 2005 Volcanic Activity in Alaska, Kamchatka, and the Kurile Islands: Summary of Events and Response of the Alaska Volcano Observatory

    USGS Publications Warehouse

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

    2008-01-01

    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.

  8. Chlorine isotopes of thermal springs in arc volcanoes for tracing shallow magmatic activity

    NASA Astrophysics Data System (ADS)

    Li, Long; Bonifacie, Magali; Aubaud, Cyril; Crispi, Olivier; Dessert, Céline; Agrinier, Pierre

    2015-03-01

    The evaluation of the status of shallow magma body (i.e., from the final intrusion stage, to quiescence, and back to activity), one of the key parameters that trigger and sustain volcanic eruptions, has been challenging in modern volcanology. Among volatile tracers, chlorine (Cl) uniquely exsolves at shallow depths and is highly hydrophilic. Consequently, Cl enrichment in volcanic gases and thermal springs has been proposed as a sign for shallow magmatic activities. However, such enrichment could also result from numerous other processes (e.g., water evaporation, dissolution of old chloride mineral deposits, seawater contamination) that are unrelated to magmatic activity. Here, based on stable isotope compositions of chloride and dissolved inorganic carbon, as well as previous published 3He/4He data obtained in thermal springs from two recently erupted volcanoes (La Soufrière in Guadeloupe and Montagne Pelée in Martinique) in the Lesser Antilles Arc, we show that the magmatic Cl efficiently trapped in thermal springs displays negative δ37Cl values (≤ - 0.65 ‰), consistent with a slab-derived origin but distinct from the isotope compositions of chloride in surface reservoirs (e.g. seawater, local meteoric waters, rivers and cold springs) displaying common δ37Cl values of around 0‰. Using this δ37Cl difference as an index of magmatic Cl, we further examined thermal spring samples including a 30-year archive from two thermal springs in Guadeloupe covering samples from its last eruption in 1976-1977 to 2008 and an island-wide sampling event in Martinique in 2008 to trace the evolution of magmatic Cl in the volcanic hydrothermal systems over time. The results show that magmatic Cl can be rapidly flushed out of the hydrothermal systems within <30 to 80 years after the eruption, much quicker than other volatile tracers such as CO2 and noble gases, which can exsolve at greater depths and constantly migrate to the surface. Because arc volcanoes often have well

  9. The Pulse of the Volcano: Discovery of Episodic Activity at Prometheus on Io

    NASA Technical Reports Server (NTRS)

    Davies, A. G.

    2003-01-01

    The temporal behaviour of thermal output from a volcano yields valuable clues to the processes taking place at and beneath the surface. Galileo Near Infrared Mapping Spectrometer (NIMS) data show that the ionian volcanoes Prometheus and Amirani have significant thermal emission in excess of nonvolcanic background emission in every geometrically appropriate NIMS observation. The 5 micron brightness of these volcanoes shows considerable variation from orbit to orbit. Prometheus in particular exhibits an episodicity that yields valuable constraints to the mechanisms of magma supply and eruption. This work is part of an on-going study to chart and quantify the thermal emission of Io's volcanoes, determine mass eruption rates, and note eruption style.

  10. Icelandic Volcanoes Geohazard Supersite and FUTUREVOLC: role of interferometric synthetic aperture radar to identify renewed unrest and track magma movement beneath the most active volcanoes in Iceland

    NASA Astrophysics Data System (ADS)

    Parks, Michelle; Dumont, Stéphanie; Spaans, Karsten; Drouin, Vincent; Sigmundsson, Freysteinn; Hooper, Andrew; Michalczewska, Karolina; Ófeigsson, Benedikt

    2014-05-01

    FUTUREVOLC is an integrated volcano monitoring project, funded by the European Commission (FP7) and led by the University of Iceland and the Icelandic Meteorological Office (IMO). The project is a European collaborative effort, comprising 26 partners, aimed at integrating ground based and satellite observations for improved monitoring and evaluation of volcanic hazards. Iceland has also recently been declared a Geohazard Supersite by the Committee on Earth Observation Satellites, based on its propensity for relatively frequent eruptions and their potentially hazardous, long ranging effects. Generating a long-term time series of ground displacements is key to gaining a better understanding of sub-volcanic processes, including the detection of new melt and migration of magma within the crust. The focus of the FUTUREVOLC deformation team is to generate and interpret an extended time series of high resolution deformation measurements derived from InSAR observations, in the vicinity of the four most active volcanoes in Iceland: Grímsvötn, Katla, Hekla and Bárdarbunga. A comprehensive network of continuous deformation monitoring equipment, led by IMO and collaborators, is already deployed at these volcanoes, including GPS, tilt and borehole strainmeters. InSAR observations are complementary to field based measurements and their high spatial resolution assists in resolving the geometry and location of the source of the deformation. InSAR and tilt measurements at Hekla indicate renewed melt supply to a sub-volcanic reservoir after the last eruption in 2000. Recent deformation studies utilising data spanning this eruption, have provided insight into the shallow plumbing system which may explain the large reduction in eruption repose interval following the 1970 eruption. Although InSAR and GPS observations at Katla volcano (between 2001 and 2009) suggest no indication of magma induced deformation outside the ice-cap, it is possible that a small flood at Mýrdalsjökull in

  11. Geology of the Ugashik-Mount Peulik Volcanic Center, Alaska

    USGS Publications Warehouse

    Miller, Thomas P.

    2004-01-01

    The Ugashik-Mount Peulik volcanic center, 550 km southwest of Anchorage on the Alaska Peninsula, consists of the late Quaternary 5-km-wide Ugashik caldera and the stratovolcano Mount Peulik built on the north flank of Ugashik. The center has been the site of explosive volcanism including a caldera-forming eruption and post-caldera dome-destructive activity. Mount Peulik has been formed entirely in Holocene time and erupted in 1814 and 1845. A large lava dome occupies the summit crater, which is breached to the west. A smaller dome is perched high on the southeast flank of the cone. Pyroclastic-flow deposits form aprons below both domes. One or more sector-collapse events occurred early in the formation of Mount Peulik volcano resulting in a large area of debris-avalanche deposits on the volcano's northwest flank. The Ugashik-Mount Peulik center is a calcalkaline suite of basalt, andesite, dacite, and rhyolite, ranging in SiO2 content from 51 to 72 percent. The Ugashik-Mount Peulik magmas appear to be co-genetic in a broad sense and their compositional variation has probably resulted from a combination of fractional crystallization and magma-mixing. The most likely scenario for a future eruption is that one or more of the summit domes on Mount Peulik are destroyed as new magma rises to the surface. Debris avalanches and pyroclastic flows may then move down the west and, less likely, east flanks of the volcano for distances of 10 km or more. A new lava dome or series of domes would be expected to form either during or within some few years after the explosive disruption of the previous dome. This cycle of dome disruption, pyroclastic flow generation, and new dome formation could be repeated several times in a single eruption. The volcano poses little direct threat to human population as the area is sparsely populated. The most serious hazard is the effect of airborne volcanic ash on aircraft since Mount Peulik sits astride heavily traveled air routes connecting the U

  12. Broadband seismic monitoring of active volcanoes using deterministic and stochastic approaches

    NASA Astrophysics Data System (ADS)

    Kumagai, H.; Nakano, M.; Maeda, T.; Yepes, H.; Palacios, P.; Ruiz, M. C.; Arrais, S.; Vaca, M.; Molina, I.; Yamashina, T.

    2009-12-01

    We systematically used two approaches to analyze broadband seismic signals observed at active volcanoes: one is waveform inversion of very-long-period (VLP) signals in the frequency domain assuming possible source mechanisms; the other is a source location method of long-period (LP) and tremor using their amplitudes. The deterministic approach of the waveform inversion is useful to constrain the source mechanism and location, but is basically only applicable to VLP signals with periods longer than a few seconds. The source location method uses seismic amplitudes corrected for site amplifications and assumes isotropic radiation of S waves. This assumption of isotropic radiation is apparently inconsistent with the hypothesis of crack geometry at the LP source. Using the source location method, we estimated the best-fit source location of a VLP/LP event at Cotopaxi using a frequency band of 7-12 Hz and Q = 60. This location was close to the best-fit source location determined by waveform inversion of the VLP/LP event using a VLP band of 5-12.5 s. The waveform inversion indicated that a crack mechanism better explained the VLP signals than an isotropic mechanism. These results indicated that isotropic radiation is not inherent to the source and only appears at high frequencies. We also obtained a best-fit location of an explosion event at Tungurahua when using a frequency band of 5-10 Hz and Q = 60. This frequency band and Q value also yielded reasonable locations for the sources of tremor signals associated with lahars and pyroclastic flows at Tungurahua. The isotropic radiation assumption may be valid in a high frequency range in which the path effect caused by the scattering of seismic waves results in an isotropic radiation pattern of S waves. The source location method may be categorized as a stochastic approach based on the nature of scattering waves. We further applied the waveform inversion to VLP signals observed at only two stations during a volcanic crisis

  13. Noble gas isotopic ratios from historical lavas and fumaroles at Mount Vesuvius (southern Italy): constraints for current and future volcanic activity

    NASA Astrophysics Data System (ADS)

    Tedesco, Dario; Nagao, Keisuke; Scarsi, Paolo

    1998-12-01

    Helium, neon and argon isotope ratios have been analysed from phenocrysts of eleven lava samples belonging to the last eruptive cycle of Mount Vesuvius (1631 until 1944). The phenocrysts separates include pyroxene ( N=10) and olivine ( N=1). All phenocryst samples show similarly low gas contents (He, Ne and Ar ˜10 -10 cm 3/g). 3He/ 4He ratios, 5.3-2.11 Ra, are generally low if compared to those typical of the MORB and those of the European Subcontinental Mantle (ESCM), respectively R/ Ra 8.5±1 and 6.0-6.5. A decreasing trend is found from 1631 to 1796, while a more homogeneous set of data is obtained for more recent eruptions, as evidenced by an average R/ Ra value of 2.85. Neon ratios ( 21Ne/ 22Ne and 20Ne/ 22Ne) strongly differ from those typically found on volcanoes and suggest that a crustal component has been added in the source region to Mt. Vesuvius magmas. Argon ratios ( 40Ar/ 36Ar and 38Ar/ 36Ar) have values similar to the atmosphere and are well correlated. The low 40Ar/ 36Ar ratio (max. 302) is, however, in the range of the 40Ar/ 36Ar ratios obtained from several lava samples at other Italian volcanoes and might be considered to have a deep origin. Two hypothesis have been discussed: (1) a deep argon-like-air source, due to subduction of air-rich sediments and/or (2) a preferential loss of Ar, in comparison to lighter noble gases, from silicic melts. Helium isotopic analysis of gas samples recently collected from crater and submarine fumaroles are similar to those of lavas belonging to the final part of this eruptive cycle. This result supports the idea that no new juvenile fluids from the source region have been injected into the magmatic reservoir during the 1631-1944 eruptive cycle and, more importantly, until 1993. Both sets of data help to understand the genesis of these fluids and to constrain the current activity of the volcano.

  14. Volcanomagnetic signals associated with the quasi-continuous activity of the andesitic Merapi volcano, Indonesia: 1990-1995

    NASA Astrophysics Data System (ADS)

    Zlotnicki, J.; Bof, M.

    Merapi volcano in Java island (Indonesia) is an andesitic stratovolcano which presents long periods of effusive activity during which an endogeneous dome is continuously growing. The viscous lava dome gives rise to unstable blocks which collapse or turn into pyroclastic flows. When the volcano does not exhibit any surface activity, the overpressure within the volcano slowly increases. Depending on the quietness duration, the unrest of the volcano can start with an explosive phase during which the former dome is partly destroyed. Magnetic variations of different time constant are observed during the 1990-1995 period which includes one gas plume emission on August 26, 1990 and two eruptions on January 20, 1992 and on November 22, 1994. Compared with other types of active volcanoes, the observed volcanomagnetic variations are very small, at the most a few nanoteslas (nT). To discriminate the variations associated with the global activity from the signals correlated with each unrest phase, one has to dissociate the different time constant variations over the six-year time span. When long-term trends are removed from the magnetic field in each station of the network, an outstanding correlation between all the magnetic differences is emphasised. The midterm variations point out 2 cycles of activity which fit the stress field evolution within the edifice leading to the 1992 and 1994 eruptions. A new cycle has started in May 1995. In every identified cycle, rapid volcanomagnetic signals are well associated with stress field changes (May 1991, September 1991, February 1993, December 1993, …). Some of the volcanomagnetic variations are short-term precursory signals as the three months decrease, up to 1.3 nT, preceding the 1992 eruption. The comparison between magnetic data, seismicity and surface phenomena implies that the midterm volcanomagnetic variations associated with the cycles of Merapi activity are of piezomagnetic origin.

  15. Active mud volcanoes on the continental slope of the Canadian Beaufort Sea

    NASA Astrophysics Data System (ADS)

    Paull, C. K.; Dallimore, S. R.; Caress, D. W.; Gwiazda, R.; Melling, H.; Riedel, M.; Jin, Y. K.; Hong, J. K.; Kim, Y.-G.; Graves, D.; Sherman, A.; Lundsten, E.; Anderson, K.; Lundsten, L.; Villinger, H.; Kopf, A.; Johnson, S. B.; Hughes Clarke, J.; Blasco, S.; Conway, K.; Neelands, P.; Thomas, H.; Côté, M.

    2015-09-01

    Morphologic features, 600-1100 m across and elevated up to 30 m above the surrounding seafloor, interpreted to be mud volcanoes were investigated on the continental slope in the Beaufort Sea in the Canadian Arctic. Sediment cores, detailed mapping with an autonomous underwater vehicle, and exploration with a remotely operated vehicle show that these are young and actively forming features experiencing ongoing eruptions. Biogenic methane and low-chloride, sodium-bicarbonate-rich waters are extruded with warm sediment that accumulates to form cones and low-relief circular plateaus. The chemical and isotopic compositions of the ascending water indicate that a mixture of meteoric water, seawater, and water from clay dehydration has played a significant role in the evolution of these fluids. The venting methane supports extensive siboglinid tubeworms communities and forms some gas hydrates within the near seafloor. We believe that these are the first documented living chemosynthetic biological communities in the continental slope of the western Arctic Ocean.

  16. Volcanogenic fluorine in rainwater around active degassing volcanoes: Mt. Etna and Stromboli Island, Italy.

    PubMed

    Bellomo, S; D'Alessandro, W; Longo, M

    2003-01-01

    Many studies have assessed the strong influence of volcanic activity on the surrounding environment. This is particularly true for strong gas emitters such as Mt. Etna and Stromboli volcanoes. Among volcanic gases, fluorine compounds are potentially very harmful. Fluorine cycling through rainwater in the above volcanic areas was studied analysing more than 400 monthly bulk samples. Data indicate that only approximately 1% of fluorine emission through the plume is deposited on the two volcanic areas by meteoric precipitations. Although measured bulk rainwater fluorine fluxes are comparable to and sometimes higher than in heavily polluted areas, their influence on the surrounding vegetation is limited. Only annual crops, in fact, show some damage that could be an effect of fluorine deposition, indicating that long-living endemic plant species or varieties have developed some kind of resistance.

  17. Attaining high-resolution eruptive histories for active arc volcanoes with argon geochronology

    NASA Astrophysics Data System (ADS)

    Calvert, A. T.

    2012-04-01

    Geochronology of active arc volcanoes commonly illuminates eruptive behavior over tens to hundreds of thousands of years, lengthy periods of repose punctuated by short eruptive episodes, and spatial and compositional changes with time. Despite the >1 Gyr half-life of 40K, argon geochronology is an exceptional tool for characterizing Pleistocene to Holocene eruptive histories and for placing constraints on models of eruptive behavior. Reliable 40Ar/39Ar ages of calc-alkaline arc rocks with rigorously derived errors small enough (± 500 to 3,000 years) to constrain eruptive histories are attainable using careful procedures. Sample selection and analytical work in concert with geologic mapping and stratigraphic studies are essential for determining reliable eruptive histories. Preparation, irradiation and spectrometric techniques have all been optimized to produce reliable, high-precision results. Examples of Cascade and Alaska/Aleutian eruptive histories illustrating duration of activity from single centers, eruptive episodicity, and spatial and compositional changes with time will be presented: (1) Mt. Shasta, the largest Cascade stratovolcano, has a 700,000-year history (Calvert and Christiansen, 2011 Fall AGU). A similar sized and composition volcano (Rainbow Mountain) on the Cascade axis was active 1200-950 ka. The eruptive center then jumped west 15 km to the south flank of the present Mt. Shasta and produced a stratovolcano from 700-450 ka likely rivaling today's Mt. Shasta. The NW portion of that edifice failed in an enormous (>30 km3) debris avalanche. Vents near today's active summit erupted 300-135 ka, then 60-15 ka. A voluminous, but short-lived eruptive sequence occurred at 11 ka, including a summit explosion producing a subplinian plume, followed by >60 km3 andesite-dacite Shastina domes and flows, then by the flank dacite Black Butte dome. Holocene domes and flows subsequently rebuilt the summit and flowed to the north and east. (2) Mt. Veniaminof on

  18. Developments in analysis of basaltic ash applied to recent activity at Etna and Stromboli volcanoes

    NASA Astrophysics Data System (ADS)

    Lautze, N. C.; Taddeucci, J.; Andronico, D.; Tornetta, L.; Cannata, C.; Houghton, B. F.; Cristaldi, A.

    2009-12-01

    Advances in analytical techniques coupled with recent high levels of activity at Etna and Stromboli have offered a unique opportunity to sample and analyze of basaltic ash particles. We have performed new micro-scale analysis of basaltic ash from a variety of eruptive conditions: a weak ash-producing event at Etna on 11 November 2006, ash emission, paroxysmal explosions and lava-sea water interaction during the 2007 eruptive crisis of Stromboli volcano, and finally more typical Strombolian activity in 2008 at Stromboli. Etna samples were collected at eight locations between 2 and 20 km from source. Stromboli samples were collected between 28 February and 19 March 2007, and from single explosions in September 2008. A JEOL JSM 6500 Field Emission Scanning Electron Microprobe (FE-SEM) was used to image and quantify millimeter- to submicron-scale features of ash particles. Beside qualitative observation of the particles, semi-automated FE-SEM data include particle morphoscopy (area, perimeter, compactness, equivalent diameter) and surface chemistry. The morphoscopy data can be compared to grain size data collected by conventional techniques, while the surface chemistry data can be considered a proxy for component analysis, more typically performed using a binocular microscope, as it reflects the degree of crystallinity and alteration of the particles. Preliminary data indicate that insight into the particle source and eruptive dynamics of both volcanoes can be obtained from detailed analysis of the ash. In particular, the different sources of ash at Stromboli have highly distinctive alteration signatures, while the Etna samples exemplify the potential of the approach to discern subtle differences in ash particles from the same plume collected at different locations, thus outlining relatively small-scale plume zonations.

  19. How caldera collapse shapes the shallow emplacement and transfer of magma in active volcanoes

    NASA Astrophysics Data System (ADS)

    Corbi, Fabio; Rivalta, Eleonora; Pinel, Virginie; Maccaferri, Francesco; Bagnardi, Marco; Acocella, Valerio

    2016-04-01

    Calderas are topographic depressions formed by the collapse of a partly drained magma reservoir. At volcanic edifices with calderas, eruptive fissures can circumscribe the outer caldera rim, be oriented radially and/or align with the regional tectonic stress field. Constraining the mechanisms that govern this spatial arrangement is fundamental to understand the dynamics of shallow magma storage and transport and evaluate volcanic hazard. Here we use numerical models to show that the previously unappreciated unloading effect of caldera formation may contribute significantly to the stress budget of a volcano. We first test this hypothesis against the ideal case of Fernandina, Galápagos, where previous models only partly explained the peculiar pattern of circumferential and radial eruptive fissures and the geometry of the intrusions determined by inverting the deformation data. We show that by taking into account the decompression due to the caldera formation, the modeled edifice stress field is consistent with all the observation. We then develop a general model for the stress state at volcanic edifices with calderas based on the competition of caldera decompression, magma buoyancy forces and tectonic stresses. These factors control the shallow accumulation of magma in stacked sills, consistently with observations as well as the conditions for the development of circumferential and/or radial eruptive fissures, as observed on active volcanoes. This top-down control exerted by changes in the distribution of mass at the surface allows better understanding of how shallow magma is transferred at active calderas, contributing to forecasting the location and type of opening fissures.

  20. Seismicity and eruptive activity at Fuego Volcano, Guatemala: February 1975 -January 1977

    USGS Publications Warehouse

    Yuan, A.T.E.; McNutt, S.R.; Harlow, D.H.

    1984-01-01

    We examine seismic and eruptive activity at Fuego Volcano (14??29???N, 90?? 53???W), a 3800-m-high stratovolcano located in the active volcanic arc of Guatemala. Eruptions at Fuego are typically short-lived vulcanian eruptions producing ash falls and ash flows of high-alumina basalt. From February 1975 to December 1976, five weak ash eruptions occurred, accompanied by small earthquake swarms. Between 0 and 140 (average ??? 10) A-type or high-frequency seismic events per day with M > 0.5 were recorded during this period. Estimated thermal energies for each eruption are greater by a factor of 106 than cumulative seismic energies, a larger ratio than that reported for other volcanoes. Over 4000 A-type events were recorded January 3-7, 1977 (cumulative seismic energy ??? 109 joules), yet no eruption occurred. Five 2-hour-long pulses of intense seismicity separated by 6-hour intervals of quiescence accounted for the majority of events. Maximum likelihood estimates of b-values range from 0.7 ?? 0.2 to 2.1 ?? 0.4 with systematically lower values corresponding to the five intense pulses. The low values suggest higher stress conditions. During the 1977 swarm, a tiltmeter located 6 km southeast of Fuego recorded a 14 ?? 3 microradian tilt event (down to SW). This value is too large to represent a simple change in the elastic strain field due to the earthquake swarm. We speculate that the earthquake swarm and tilt are indicative of subsurface magma movement. ?? 1984.

  1. Volcano infrasound: A review

    NASA Astrophysics Data System (ADS)

    Johnson, Jeffrey Bruce; Ripepe, Maurizio

    2011-09-01

    Exploding volcanoes, which produce intense infrasound, are reminiscent of the veritable explosion of volcano infrasound papers published during the last decade. Volcano infrasound is effective for tracking and quantifying eruptive phenomena because it corresponds to activity occurring near and around the volcanic vent, as opposed to seismic signals, which are generated by both surface and internal volcanic processes. As with seismology, infrasound can be recorded remotely, during inclement weather, or in the dark to provide a continuous record of a volcano's unrest. Moreover, it can also be exploited at regional or global distances, where seismic monitoring has limited efficacy. This paper provides a literature overview of the current state of the field and summarizes applications of infrasound as a tool for better understanding volcanic activity. Many infrasound studies have focused on integration with other geophysical data, including seismic, thermal, electromagnetic radiation, and gas spectroscopy and they have generally improved our understanding of eruption dynamics. Other work has incorporated infrasound into volcano surveillance to enhance capabilities for monitoring hazardous volcanoes and reducing risk. This paper aims to provide an overview of volcano airwave studies (from analog microbarometer to modern pressure transducer) and summarizes how infrasound is currently used to infer eruption dynamics. It also outlines the relative merits of local and regional infrasound surveillance, highlights differences between array and network sensor topologies, and concludes with mention of sensor technologies appropriate for volcano infrasound study.

  2. Iceland Volcano

    Atmospheric Science Data Center

    2013-04-23

    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 ...

  3. Long-term monitoring on active volcanoes. Time relationship between surface variations of temperature and changes of energy release from magmatic sources, verified by multi-parameter and interdisciplinary comparisons

    NASA Astrophysics Data System (ADS)

    Diliberto, I. S.; Bellomo, S.; Camarda, M.; D'Alessandro, W.; Gagliano Candela, E.; Gagliano, A. L.; Longo, M.; Pisciotta, F.; Pecoraino, G.; Vita, F.

    2015-12-01

    The longest records of temperature data from active volcanoes in southern Italy are presented. One dataset comes from continuous monitoring of fumaroles temperature of la Fossa cone of Vulcano (Aeolian Islands), it runs from 1990 to 2014, but the first measurements started in 1984. Another dataset is from thermal aquifers of Mount Etna volcano, since 1989 the acquisition period has been one month, more recently data with hourly frequency are registered on the continuous monitoring network. Both monitoring systems are still ongoing. In 1984 at Vulcano the monitoring of fumaroles suffered of a pioneering approach, our technicians faced for the first time with extreme condition, absence of energy power, temperature range covering up to 2 order of magnitude (from normal ambient to several hundreds °C), steam, corrosive acidic fluids released by fumaroles (Sulphur and Chlorine compounds, Carbon dioxide). The experience matured in the high temperature fumarole field of Vulcano can be useful to support new surveillance programs on other volcanoes around the world. Time series analysis applied to fumaroles temperature highlighted the cyclic character of the main observed variations and major trends, lasting some years. Long term monitoring allowed comparisons of many temperature subsets with other validated geochemical and geophysical dataseries and highlighted common source mechanisms accounting for endogenous processes. Changes in the magma source and/or seismo-tectonic activity are the primary causes of the main time variations. A similar comparative approach has been applied to time series of temperature data recorded on Etna volcano. Time relationships have been found with the eruptive activity, particularly with the emission rates of volcanic products, although the monitoring sites are far from the eruptive vents. The collected data show confirmation about the effectiveness of the geochemical approach to follow in real time changes from the source, even being far

  4. International Volcanological Field School in Kamchatka and Alaska: Experiencing Language, Culture, Environment, and Active Volcanoes

    NASA Astrophysics Data System (ADS)

    Eichelberger, J. C.; Gordeev, E.; Ivanov, B.; Izbekov, P.; Kasahara, M.; Melnikov, D.; Selyangin, O.; Vesna, Y.

    2003-12-01

    The Kamchatka State University of Education, University of Alaska Fairbanks, and Hokkaido University are developing an international field school focused on explosive volcanism of the North Pacific. An experimental first session was held on Mutnovsky and Gorely Volcanoes in Kamchatka during August 2003. Objectives of the school are to:(1) Acquaint students with the chemical and physical processes of explosive volcanism, through first-hand experience with some of the most spectacular volcanic features on Earth; (2) Expose students to different concepts and approaches to volcanology; (3) Expand students' ability to function in a harsh environment and to bridge barriers in language and culture; (4) Build long-lasting collaborations in research among students and in teaching and research among faculty in the North Pacific region. Both undergraduate and graduate students from Russia, the United States, and Japan participated. The school was based at a mountain hut situated between Gorely and Mutnovsky Volcanoes and accessible by all-terrain truck. Day trips were conducted to summit craters of both volcanoes, flank lava flows, fumarole fields, ignimbrite exposures, and a geothermal area and power plant. During the evenings and on days of bad weather, the school faculty conducted lectures on various topics of volcanology in either Russian or English, with translation. Although subjects were taught at the undergraduate level, lectures led to further discussion with more advanced students. Graduate students participated by describing their research activities to the undergraduates. A final session at a geophysical field station permitted demonstration of instrumentation and presentations requiring sophisticated graphics in more comfortable surroundings. Plans are underway to make this school an annual offering for academic credit in the Valley of Ten Thousand Smokes, Alaska and in Kamchatka. The course will be targeted at undergraduates with a strong interest in and

  5. A forward modeling approach to relate geophysical observables at active volcanoes to deep magma dynamics

    NASA Astrophysics Data System (ADS)

    Montagna, C. P.; Longo, A.; Papale, P.; Vassalli, M.; Saccorotti, G.; Cassioli, A.

    2010-12-01

    Geophysical signals usually recorded at active volcanoes mainly consist of i) seismicity - high frequency volcano-tectonic events, volcanic tremor, and LP, VLP, and ULP events, ii) ground displacement, and iii) gravity changes. These signals are inverted to constrain the characteristics of the underground signal source, usually under the simplifying assumptions of point source or small volume homogeneous source with simple geometry. We have instead designed a forward approach, that complements the more classical inverse approaches, whereby magma chamber dynamics are numerically solved for compressible-to-incompressible multi-component magmas in geometrically complex systems constituted by one or more magma chambers connected through dykes. Our new code, that we named GALES (GAlerkin LEast Squares), solves the complex time-space-dependent dynamics of convection and mixing of magmas with different composition and properties, and reveals patterns of overpressure much more complex than commonly assumed in inverse analyses. Time-space-dependent stress distributions computed along the rigid magma-wall boundaries are employed as boundary conditions in either numerical simulations of wave propagation through the rock system by taking into account wall rock heterogeneities and topographic surface, or semi-analytical solutions of the Green’s functions in homogeneous infinite space. Ground displacement computed at the topographic surface ranges from the seismic to the quasi-static frequency band. Density variations associated to the simulated magma convection dynamics are instead employed to determine the corresponding gravity change at the surface. Seismicity, ground deformation, and gravity changes associated to deep magma dynamics are therefore computed as a function of time at different points on the Earth’s surface. Performed numerical simulations involve cases with largely different magma/dyke size, geometry and depth, and magma compositions from basaltic to

  6. Instrumental neutron activation analysis data for cloud-water particulate samples, Mount Bamboo, Taiwan

    USGS Publications Warehouse

    Lin, Neng-Huei; Sheu, Guey-Rong; Wetherbee, Gregory A.; Debey, Timothy M.

    2013-01-01

    Cloud water was sampled on Mount Bamboo in northern Taiwan during March 22-24, 2002. Cloud-water samples were filtered using 0.45-micron filters to remove particulate material from the water samples. Filtered particulates were analyzed by instrumental neutron activation analysis (INAA) at the U.S. Geological Survey National Reactor Facility in Denver, Colorado, in February 2012. INAA elemental composition data for the particulate materials are presented. These data complement analyses of the aqueous portion of the cloud-water samples, which were performed earlier by the Department of Atmospheric Sciences, National Central University, Taiwan. The data are intended for evaluation of atmospheric transport processes and air-pollution sources in Southeast Asia.

  7. Nicaraguan Volcanoes

    Atmospheric Science Data Center

    2013-04-18

    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 ...

  8. Linking observations at active volcanoes to physical processes through conduit flow modelling

    NASA Astrophysics Data System (ADS)

    Thomas, Mark; Neuberg, Jurgen

    2010-05-01

    Low frequency seismic events observed on volcanoes such as Soufriere hills, Montserrat may offer key indications about the state of a volcanic system. To obtain a better understanding of the source of these events and of the physical processes that take place within a volcano it is necessary to understand the conditions of magma a depth. This can be achieved through conduit flow modelling (Collier & Neuberg, 2006). 2-D compressible Navier-Stokes equations are solved through a Finite Element approach, for differing initial water and crystal contents, magma temperatures, chamber overpressures and geometric shapes of conduit. In the fully interdependent modelled system each of these variables has an effect on the magma density, viscosity, gas content, and also the pressure within the flow. These variables in turn affect the magma ascent velocity and the overall eruption dynamics of an active system. Of particular interest are the changes engendered in the flow by relativity small variations in the conduit geometry. These changes can have a profound local effect of the ascent velocity of the magma. By restricting the width of 15m wide, 5000m long vertical conduit over a 100m distance a significant acceleration of the magma is seen in this area. This has implications for the generation of Low-Frequency (LF) events at volcanic systems. The strain-induced fracture of viscoelastic magma or brittle failure of melt has been previously discussed as a possible source of LF events by several authors (e.g. Tuffen et al., 2003; Neuberg et al., 2006). The location of such brittle failure however has been seen to occur at relativity shallow depths (<1000m), which does not agree with the location of recorded LF events. By varying the geometry of the conduit and causing accelerations in the magma flow, localised increases in the shear strain rate of up to 30% are observed. This provides a mechanism of increasing the depth over witch brittle failure of melt may occur. A key observable

  9. Organic geochemical signatures controlling methane outgassing at active mud volcanoes in the Canadian Beaufort Sea

    NASA Astrophysics Data System (ADS)

    DongHun, Lee; YoungKeun, Jin; JungHyun, Kim; Heldge, Niemann; JongKu, Gal; BoHyung, Choi

    2016-04-01

    Based on the water column acoustic anomalies related to active methane (CH4) venting, numerous active Mud Volcanoes (MVs) were recently identified at ~282, ~420, and ~740 m water depths on the continental slope of the Canadian Beaufort Sea (Paull et al., 2015). While geophysical aspects such as the multibeam bathymetric mapping are thoroughly investigated, biogeochemical processes controlling outgassing CH4 at the active MVs are not well constrained. Here, we investigated three sediment cores from the active MVs and one sediment core from a non-methane influenced reference site recovered during the ARA-05C expedition with the R/V ARAON in 2014. We analyzed lipid biomarkers and their stable carbon isotopic values (δ13C) in order to determine key biogeochemical processes involved in CH4 cycling in the MV sediments. Downcore CH4 and sulphate (SO42-) concentration measurements revealed a distinct sulfate-methane transition zone (SMTZ) at the shallow sections of the cores (15 - 45 cm below seafloor (cm bsf) at 282 m MV, 420 m MV, and 740 m MV). The most abundant diagnostic lipid biomarkers in the SMTZ were sn-2-hydroxyarchaeol (-94‰) and archaeol (-66‰) with the sn-2-hydroxyarchaeol: archaeol ratio of 1.1 to 5, indicating the presence of ANME-2 or -3. However, we also found substantial amounts of monocyclic biphytane-1 (BP-1, -118‰), which is rather indicative for ANME-1. Nevertheless, the concentration of sn-2-hydroxyarchaeol was 2-fold higher than any other archaeal lipids, suggesting a predominant ANME-2 or -3 rather than ANME-1 as a driving force for the anaerobic methane oxidation (AOM) in these systems. We will further investigate the microbial community at the active MVs using nucleic acid (RNA and DNA) sequence analyses in near future. Our study provides first biogeochemical data set of the active MVs in the Canadian Beaufort Sea, which helps to better understand CH4 cycling mediated in these systems. Reference Paull, C.K., et al. (2015), Active mud

  10. Living with Volcanoes: Year Eleven Teaching Resource Unit.

    ERIC Educational Resources Information Center

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

    2000-01-01

    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)

  11. Micro-earthquake signal analysis and hypocenter determination around Lokon volcano complex

    SciTech Connect

    Firmansyah, Rizky; Nugraha, Andri Dian; Kristianto

    2015-04-24

    Mount Lokon is one of five active volcanoes which is located in the North Sulawesi region. Since June 26{sup th}, 2011, standby alert set by the Center for Volcanology and Geological Hazard Mitigation (CVGHM) for this mountain. The Mount Lokon volcano erupted on July 4{sup th}, 2011 and still continuously erupted until August 28{sup th}, 2011. Due to its high seismic activity, this study is focused to analysis of micro-earthquake signal and determine the micro-earthquake hypocenter location around the complex area of Lokon-Empung Volcano before eruption phase in 2011 (time periods of January, 2009 up to March, 2010). Determination of the hypocenter location was conducted with Geiger Adaptive Damping (GAD) method. We used initial model from previous study in Volcan de Colima, Mexico. The reason behind the model selection was based on the same characteristics that shared between Mount Lokon and Colima including andesitic stratovolcano and small-plinian explosions volcanian types. In this study, a picking events was limited to the volcano-tectonics of A and B types, hybrid, long-period that has a clear signal onset, and local tectonic with different maximum S – P time are not more than three seconds. As a result, we observed the micro-earthquakes occurred in the area north-west of Mount Lokon region.

  12. Experimental and analytical study of secondary path variations in active engine mounts

    NASA Astrophysics Data System (ADS)

    Hausberg, Fabian; Scheiblegger, Christian; Pfeffer, Peter; Plöchl, Manfred; Hecker, Simon; Rupp, Markus

    2015-03-01

    Active engine mounts (AEMs) provide an effective solution to further improve the acoustic and vibrational comfort of passenger cars. Typically, adaptive feedforward control algorithms, e.g., the filtered-x-least-mean-squares (FxLMS) algorithm, are applied to cancel disturbing engine vibrations. These algorithms require an accurate estimate of the AEM active dynamic characteristics, also known as the secondary path, in order to guarantee control performance and stability. This paper focuses on the experimental and theoretical study of secondary path variations in AEMs. The impact of three major influences, namely nonlinearity, change of preload and component temperature, on the AEM active dynamic characteristics is experimentally analyzed. The obtained test results are theoretically investigated with a linear AEM model which incorporates an appropriate description for elastomeric components. A special experimental set-up extends the model validation of the active dynamic characteristics to higher frequencies up to 400 Hz. The theoretical and experimental results show that significant secondary path variations are merely observed in the frequency range of the AEM actuator's resonance frequency. These variations mainly result from the change of the component temperature. As the stability of the algorithm is primarily affected by the actuator's resonance frequency, the findings of this paper facilitate the design of AEMs with simpler adaptive feedforward algorithms. From a practical point of view it may further be concluded that algorithmic countermeasures against instability are only necessary in the frequency range of the AEM actuator's resonance frequency.

  13. Cotopaxi volcano's unrest and eruptive activity in 2015: mild awakening after 73 years of quiescence

    NASA Astrophysics Data System (ADS)

    Hidalgo, Silvana; Bernard, Benjamin; Battaglia, Jean; Gaunt, Elizabeth; Barrington, Charlotte; Andrade, Daniel; Ramón, Patricio; Arellano, Santiago; Yepes, Hugo; Proaño, Antonio; Almeida, Stefanie; Sierra, Daniel; Dinger, Florian; Kelly, Peter; Parra, René; Bobrowski, Nicole; Galle, Bo; Almeida, Marco; Mothes, Patricia; Alvarado, Alexandra

    2016-04-01

    Cotopaxi volcano (5,897 m) is located 50 km south of Quito, the capital of Ecuador. The most dangerous hazards of this volcano are the devastating lahars that can be generated by the melting of its ice cap during pyroclastic flow-forming eruptions. The first seismic station was installed in 1976. Cotopaxi has been monitored by the Instituto Geofísico (Escuela Politécnica Nacional) since 1983. Presently the monitoring network is comprised of 11 broadband and 5 short period seismometers, 4 scanning DOAS, 1 infrared and 5 visible cameras, 7 DGPS, 5 tiltmeters, 11 AFM (lahar detectors) and a network of ashmeters. Due to the recent unrest, the monitoring of the volcano has been complemented by campaign airborne Multi-GAS and thermal IR measurements and ground-based mobile DOAS and stationary solar FTIR. After 73 years of quiescence, the first sign of unrest was a progressive increase in the amplitude of transient seismic events in April 2015. Since May 20, an increase in SO2 emissions from ˜500 t/d to ˜3 kt/day was detected followed by the appearance of seismic tremor on June 4. Both SO2 emissions of up to 5 kt/day and seismic tremor were observed until August 14 when a swarm of volcano-tectonic earthquakes preceded the first phreatic explosions. These explosions produced ash and gas columns reaching up to 9 km above the crater. The ash fall produced by the opening phase covered over 500 km2 with a submillimetric deposit corresponding to a mass of 1.65E+8 kg (VEI 1). During this period of explosions, SO2 emission rates up to 24 kt/day were observed, the highest thus far. The ash was dominantly hydrothermally altered and oxidized lithic fragments, hydrothermal minerals (alunite, gypsum), free crystals of plagioclase and pyroxenes, and little juvenile material. Unrest continued after August 14, with three episodes of ash emission. However, the intensity of ash fallout, average seismic amplitude, and SO2 emissions during each successive episode progressively decreased

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

    USGS Publications Warehouse

    Tilling, Robert I.; Heliker, Christina; Swanson, Donald A.

    2010-01-01

    Viewing an erupting volcano is a memorable experience, one that has inspired fear, superstition, worship, curiosity, and fascination since before the dawn of civilization. In modern times, volcanic phenomena have attracted intense scientific interest, because they provide the key to understanding processes that have created and shaped more than 80 percent of the Earth's surface. The active Hawaiian volcanoes have received special attention worldwide because of their frequent spectacular eruptions, which often can be viewed and studied with relative ease and safety. In January 1987, the Hawaiian Volcano Observatory (HVO), located on the rim of Kilauea Volcano, celebrated its 75th Anniversary. In honor of HVO's Diamond Jubilee, the U.S. Geological Survey (USGS) published Professional Paper 1350 (see list of Selected Readings, page 57), a comprehensive summary of the many studies on Hawaiian volcanism by USGS and other scientists through the mid-1980s. Drawing from the wealth of data contained in that volume, the USGS also published in 1987 the original edition of this general-interest booklet, focusing on selected aspects of the eruptive history, style, and products of two of Hawai'i's active volcanoes, Kilauea and Mauna Loa. This revised edition of the booklet-spurred by the approaching Centennial of HVO in January 2012-summarizes new information gained since the January 1983 onset of Kilauea's Pu'u 'O'o-Kupaianaha eruption, which has continued essentially nonstop through 2010 and shows no signs of letup. It also includes description of Kilauea's summit activity within Halema'uma'u Crater, which began in mid-March 2008 and continues as of this writing (late 2010). This general-interest booklet is a companion to the one on Mount St. Helens Volcano first published in 1984 and revised in 1990 (see Selected Readings). Together, these publications illustrate the contrast between the two main types of volcanoes: shield volcanoes, such as those in Hawai'i, which generally

  15. Volcano hazards at Newberry Volcano, Oregon

    USGS Publications Warehouse

    Sherrod, David R.; Mastin, Larry G.; Scott, William E.; Schilling, Steven P.

    1997-01-01

    Newberry volcano is a broad shield volcano located in central Oregon. It has been built by thousands of eruptions, beginning about 600,000 years ago. At least 25 vents on the flanks and summit have been active during several eruptive episodes of the past 10,000 years. The most recent eruption 1,300 years ago produced the Big Obsidian Flow. Thus, the volcano's long history and recent activity indicate that Newberry will erupt in the future. The most-visited part of the volcano is Newberry Crater, a volcanic depression or caldera at the summit of the volcano. Seven campgrounds, two resorts, six summer homes, and two major lakes (East and Paulina Lakes) are nestled in the caldera. The caldera has been the focus of Newberry's volcanic activity for at least the past 10,000 years. Other eruptions during this time have occurred along a rift zone on the volcano's northwest flank and, to a lesser extent, the south flank. Many striking volcanic features lie in Newberry National Volcanic Monument, which is managed by the U.S. Forest Service. The monument includes the caldera and extends along the northwest rift zone to the Deschutes River. About 30 percent of the area within the monument is covered by volcanic products erupted during the past 10,000 years from Newberry volcano. Newberry volcano is presently quiet. Local earthquake activity (seismicity) has been trifling throughout historic time. Subterranean heat is still present, as indicated by hot springs in the caldera and high temperatures encountered during exploratory drilling for geothermal energy. This report describes the kinds of hazardous geologic events that might occur in the future at Newberry volcano. A hazard-zonation map is included to show the areas that will most likely be affected by renewed eruptions. In terms of our own lifetimes, volcanic events at Newberry are not of day-to-day concern because they occur so infrequently; however, the consequences of some types of eruptions can be severe. When Newberry

  16. Thermal radiance observations of an active lava flow during the June 1984 eruption of Mount Etna

    SciTech Connect

    Pieri, D.C.; Glaze, L.S.; Abrams, M.J. )

    1990-10-01

    The thermal budget of an active lava flow observed on 20 June 1984 from the Southeast crater of Mount Etna, Sicily, Italy, was analyzed from data taken by the Landsat Thematic Mapper. The Thematic Mapper images constitute one of the few satellite data sets of sufficient spatial and spectral resolution to allow calibrated measurements on the distribution and intensity of thermal radiation from active lava flows. Using radiance data from two reflective infrared channels, we can estimate the temperature and areas of the hottest parts of the active flow, which correspond to hot (>500{degree}C) fractures or zones at the flow surface. Using this techniques, we estimate that only 10%-20% of the total radiated thermal power output is emitted by hot zones or fractures, which constitute less than 1% of the observed surface area. Generally, it seems that only where hot fractures or zones constitute greater than about 1% of the surface area of the flow will losses from such features significantly reduce internal flow temperatures. Using our radiance observations as boundary conditions for a multicomponent thermal model of flow interior temperature, we infer that, for the parts of this flow subject to analysis, the boundary layer and flow thickness effects dominate over radiant zones in controlling the depression of core temperature.

  17. The heartbeat of the volcano: The discovery of episodic activity at Prometheus on Io

    USGS Publications Warehouse

    Davies, A.G.; Wilson, L.; Matson, D.; Leone, G.; Keszthelyi, L.; Jaeger, W.

    2006-01-01

    The temporal signature of thermal emission from a volcano is a valuable clue to the processes taking place both at and beneath the surface. The Galileo Near Infrared Mapping Spectrometer (NIMS) observed the volcano Prometheus, on the jovian moon Io, on multiple occasions between 1996 and 2002. The 5 micron (??m) brightness of this volcano shows considerable variation from orbit to orbit. Prometheus exhibits increases in thermal emission that indicate episodic (though non-periodic) effusive activity in a manner akin to the current Pu'u 'O'o-Kupaianaha (afterwards referred to as the Pu'u 'O'o) eruption of Kilauea, Hawai'i. The volume of material erupted during one Prometheus eruption episode (defined as the interval from minimum thermal emission to peak and back to minimum) from 6 November 1996 to 7 May 1997 is estimated to be ???0.8 km3, with a peak instantaneous volumetric flux (effusion rate) of ???140 m3 s-1, and an averaged volumetric flux (eruption rate) of ???49 m3 s-1. These quantities are used to model subsurface structure, magma storage and magma supply mechanisms, and likely magma chamber depth. Prometheus appears to be supplied by magma from a relatively shallow magma chamber, with a roof at a minimum depth of ???2-3 km and a maximum depth of ???14 km. This is a much shallower depth range than sources of supply proposed for explosive, possibly ultramafic, eruptions at Pillan and Tvashtar. As Prometheus-type effusive activity is widespread on Io, shallow magma chambers containing magma of basaltic or near-basaltic composition and density may be common. This analysis strengthens the analogy between Prometheus and Pu'u 'O'o, at least in terms of eruption style. Even though the style of eruption appears to be similar (effusive emplacement of thin, insulated, compound pahoehoe flows) the scale of activity at Prometheus greatly exceeds current activity at Pu'u 'O'o in terms of volume erupted, area covered, and magma flux. Whereas the estimated magma chamber at

  18. A Fluorescein Tracer Release Experiment in the Hydrothermally Active Crater of Vailulu'u Volcano, Samoa

    NASA Astrophysics Data System (ADS)

    Hart, S. R.; Staudigel, H.; Workman, R.; Koppers, A.; Girard, A.

    2001-12-01

    Vailulu'u (Rockne) volcano marks the active end of the Samoa hotspot chain. The volcano is 4400 meters high, with a summit crater 2000 meters wide by 400 meters deep and summit peaks reaching to within 600 meters of the sea surface. The crater is hydrothermally active, as witnessed by intense particulate concentrations in the water column (values to 1.4 NTU's), a particulate smog ``halo'' surrounding the summit and extending out many kilometers, high Mn concentrations and 3He/4He ratios (values to 3.8 ppb and 8.6 Ra, respectively), and bottom-water temperature anomalies of 0.5oC. Basalts from the crater have been dated in the range 5-50 years, and likely reflect eruptions associated with a 1995 earthquake swarm. On April 3, 2001, we released a 20 kg point-source charge of fluorescein dye 30 meters above the 975m deep crater floor. The dye was dissolved in a 180 liter mixture of propanol and water, adjusted to a density 1.3 per mil heavier than the ambient water at the release depth. Released from a rubberized bag by means of a galvanic link. First detection of the released dye was 39 hours after the deployment; the dye was in a 50 meter thick layer, with a concentration peak at 900 meters (relative to the release depth of 945m). Tracking was carried out by a CTD-based fluorometer operated in tow-yo mode from the U.S.C.G. Icebreaker Polar Sea. The detection limit was 25 picograms/gram, and the maximum detected concentration was 18,000 pg/g (if evenly dispersed in the lower 150 meters of water in the crater, the expected concentration would be approx. 130 pg/g). While the dye pool was only surveyed for 4 days due to ship-transit constraints, significant horizontal and vertical dispersion was apparent. Vertical dispersion velocities were typically 0.05 cm/sec; horizontal velocities were typically higher by a factor of 10. An approximate diapycnal or eddy diffusivity, K, can be calculated from the rate of vertical spreading of the dye layer: K = Z2/2(t-t0), where Z is

  19. Seismic body wave separation in volcano-tectonic activity inferred by the Convolutive Independent Component Analysis

    NASA Astrophysics Data System (ADS)

    Capuano, Paolo; De Lauro, Enza; De Martino, Salvatore; Falanga, Mariarosaria; Petrosino, Simona

    2015-04-01

    One of the main challenge in volcano-seismological literature is to locate and characterize the source of volcano/tectonic seismic activity. This passes through the identification at least of the onset of the main phases, i.e. the body waves. Many efforts have been made to solve the problem of a clear separation of P and S phases both from a theoretical point of view and developing numerical algorithms suitable for specific cases (see, e.g., Küperkoch et al., 2012). Recently, a robust automatic procedure has been implemented for extracting the prominent seismic waveforms from continuously recorded signals and thus allowing for picking the main phases. The intuitive notion of maximum non-gaussianity is achieved adopting techniques which involve higher-order statistics in frequency domain., i.e, the Convolutive Independent Component Analysis (CICA). This technique is successful in the case of the blind source separation of convolutive mixtures. In seismological framework, indeed, seismic signals are thought as the convolution of a source function with path, site and the instrument response. In addition, time-delayed versions of the same source exist, due to multipath propagation typically caused by reverberations from some obstacle. In this work, we focus on the Volcano Tectonic (VT) activity at Campi Flegrei Caldera (Italy) during the 2006 ground uplift (Ciaramella et al., 2011). The activity was characterized approximately by 300 low-magnitude VT earthquakes (Md < 2; for the definition of duration magnitude, see Petrosino et al. 2008). Most of them were concentrated in distinct seismic sequences with hypocenters mainly clustered beneath the Solfatara-Accademia area, at depths ranging between 1 and 4 km b.s.l.. The obtained results show the clear separation of P and S phases: the technique not only allows the identification of the S-P time delay giving the timing of both phases but also provides the independent waveforms of the P and S phases. This is an enormous

  20. Very shallow dyke intrusion and potential slope failure imaged by ground deformation: The 28 December 2014 eruption on Mount Etna

    NASA Astrophysics Data System (ADS)

    Bonforte, Alessandro; Guglielmino, Francesco

    2015-04-01

    On 28 December 2014, eruptive activity resumed at Mount Etna with fire fountain activity feeding two lava flows on the eastern and southwestern upper flanks of the volcano. Unlike all previous summit activity, this eruption produced clear deformation at the summit of the volcano. GPS displacements and Sentinel-1A ascending interferograms were calculated in order to image the ground deformation pattern accompanying the eruption. The displacements observed by GPS depict a local ground deformation pattern, affecting only the upper part of the volcano. Despite snow cover on the summit, differential interferometry synthetic aperture radar (DInSAR) data allowed obtaining more detail on the ground deformation pattern on the upper eastern side of the volcano. Three-dimensional GPS displacements inversion located a very shallow NE-SW intrusion just beneath the New Southeast Crater. However, this model cannot justify all the deformation observed by DInSAR thus revealing a gravitational failure of the lava flow field.

  1. Integrating science and education during an international, multi-parametric investigation of volcanic activity at Santiaguito volcano, Guatemala

    NASA Astrophysics Data System (ADS)

    Lavallée, Yan; Johnson, Jeffrey; Andrews, Benjamin; Wolf, Rudiger; Rose, William; Chigna, Gustavo; Pineda, Armand

    2016-04-01

    In January 2016, we held the first scientific/educational Workshops on Volcanoes (WoV). The workshop took place at Santiaguito volcano - the most active volcano in Guatemala. 69 international scientists of all ages participated in this intensive, multi-parametric investigation of the volcanic activity, which included the deployment of seismometers, tiltmeters, infrasound microphones and mini-DOAS as well as optical, thermographic, UV and FTIR cameras around the active vent. These instruments recorded volcanic activity in concert over a period of 3 to 9 days. Here we review the research activities and present some of the spectacular observations made through this interdisciplinary efforts. Observations range from high-resolution drone and IR footage of explosions, monitoring of rock falls and quantification of the erupted mass of different gases and ash, as well as morphological changes in the dome caused by recurring explosions (amongst many other volcanic processes). We will discuss the success of such integrative ventures in furthering science frontiers and developing the next generation of geoscientists.

  2. Living with volcanoes

    USGS Publications Warehouse

    Wright, Thomas L.; Pierson, Thomas C.

    1992-01-01

    The 1980 cataclysmic eruption of Mount St. Helens (Lipman and Mullineaux, 1981) in southwestern Washington ushered in a decade marked by more worldwide volcanic disasters and crises than any other in recorded history. Volcanoes killed more people (over 28,500) in the 1980's than during the 78 years following 1902 eruption of Mount Pelee (Martinique). Not surprisingly, volcanic phenomena and attendant hazards received attention from government authorities, the news media, and the general public. As part of this enhanced global awareness of volcanic hazards, the U.S. Geological Survey (Bailey and others, 1983) in response to the eruptions or volcanic unrest during the 1980's at Mount St. Helens and Redoubt are still erupting intermittently, and the caldera unrest at Long Valley also continues, albeit less energetically than during the early 1980's.

  3. Subsurface mass migration at active volcanoes: what we learnt from the VOLUME project

    NASA Astrophysics Data System (ADS)

    Saccorotti, G.; Volume Team

    2009-04-01

    Movements of multiphase fluids beneath active volcanoes are generally detected at the surface in terms of changes in geophysical and geochemical observables. The prompt detection and interpretation of such signals thus represent a crucial step toward the short-term evaluation of volcanic hazard. Funded through the European 6th framework program, the VOLUME project joined 19 institutions from 6 EU and 5 extra-european countries under the common goal of improving our understanding of how subsurface mass movement manifests itself at the surface, in turn revealing the significance of such movements as precursors to impending eruptions. We integrated high-end experimental procedures with a robust modeling framework to address some of the most relevant issues of modern, quantitative volcanology. In particular, our studies focused on: (i) Unrevealing the complex interplay between hydrothermal and magmatic fluids in generating the observed geophysical / geochemical signals, (ii) Detailing the location, geometry and dynamics of magma pathways and storage zones (iii) Probing variations of the elastic parameters of volcanic media in response to stress changes induced by mass migration, and (iv) Developing a robust computational framework for forward-modelling the geophysical observables resulting from the dynamics of multiphase magmatic systems. VOLUME activities developed at both european and extra-european volcanoes. We present here the most striking results obtained at two italian test-sites, namely Etna and Campi Flegrei, for which we had available data sets of unprecedented sensitivity and temporal resolution. Results from Etna include a) mapping of the shallow plumbing system from Moment-Tensor inversion of broadband seismic signal, b) the detection of deep magma intrusion from inversion of joint gravity-tremor anomalies; c) the measurement of changes in both elastic anisotropy and seismic velocity concomitant to the waning stage of the 2002 NE flank lava effusion; and

  4. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2012

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Haney, Matthew M.; Parker, Tom; Searcy, Cheryl; Prejean, Stephanie

    2013-01-01

    Between January 1 and December 31, 2012, the Alaska Volcano Observatory located 4,787 earthquakes, of which 4,211 occurred within 20 kilometers of the 33 volcanoes monitored by a seismograph network. There was significant seismic activity at Iliamna, Kanaga, and Little Sitkin volcanoes in 2012. Instrumentation highlights for this year include the implementation of the Advanced National Seismic System Quake Monitoring System hardware and software in February 2012 and the continuation of the American Recovery and Reinvestment Act work in the summer of 2012. The operational highlight was the removal of Mount Wrangell from the list of monitored volcanoes. This catalog includes hypocenters, magnitudes, and statistics of the earthquakes located in 2012 with the station parameters, velocity models, and other files used to locate these earthquakes.

  5. Using Satellite Data to Characterize the Temporal Thermal Behavior of an Active Volcano: Mount St. Helens, WA

    NASA Technical Reports Server (NTRS)

    Vaughan, R. Greg; Hook, Simon J.

    2006-01-01

    ASTER thermal infrared data over Mt. St Helens were used to characterize its thermal behavior from Jun 2000 to Feb 2006. Prior to the Oct 2004 eruption, the average crater temperature varied seasonally between -12 and 6 C. After the eruption, maximum single-pixel temperature increased from 10 C (Oct 2004) to 96 C (Aug 2005), then showed a decrease to Feb 2006. The initial increase in temperature was correlated with dome morphology and growth rate and the subsequent decrease was interpreted to relate to both seasonal trends and a decreased growth rate/increased cooling rate, possibly suggesting a significant change in the volcanic system. A single-pixel ASTER thermal anomaly first appeared on Oct 1, 2004, eleven hours after the first eruption - 10 days before new lava was exposed at the surface. By contrast, an automated algorithm for detecting thermal anomalies in MODIS data did not trigger an alert until Dec 18. However, a single-pixel thermal anomaly first appeared in MODIS channel 23 (4 um) on Oct 13, 12 days after the first eruption - 2 days after lava was exposed. The earlier thermal anomaly detected with ASTER data is attributed to the higher spatial resolution (90 m) compared with MODIS (1 m) and the earlier visual observation of anomalous pixels compared to the automated detection method suggests that local spatial statistics and background radiance data could improve automated detection methods.

  6. ASTER Images Mt. Usu Volcano

    NASA Technical Reports Server (NTRS)

    2000-01-01

    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

  7. Nyiragonga Volcano

    NASA Technical Reports Server (NTRS)

    2001-01-01

    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 satelli