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  1. Helen Keller: A Remembrance.

    ERIC Educational Resources Information Center

    Lowenfeld, Berthold

    1980-01-01

    A well-known educator and author in the field of work with the blind recalls times he spent with Helen Keller, including her visit to the California School for the Blind, where he was superintendent, for the consecration of the Helen Keller Building. (Author/SBH)

  2. Who's Helen Keller?

    ERIC Educational Resources Information Center

    Hubbard, Ruth Shagoury

    2003-01-01

    Helen Keller was someone who worked throughout her long life to achieve social change; she was an integral part of many important social movements in the 20th century. Her life story could serve as a fascinating example for children, but most picture books about Keller are silent about her life's work. In this article, the author examines the…

  3. The Helen of Geometry

    ERIC Educational Resources Information Center

    Martin, John

    2010-01-01

    The cycloid has been called the Helen of Geometry, not only because of its beautiful properties but also because of the quarrels it provoked between famous mathematicians of the 17th century. This article surveys the history of the cycloid and its importance in the development of the calculus.

  4. Mt. St. Helens Memories.

    ERIC Educational Resources Information Center

    Sharp, Len

    1992-01-01

    Provides a personal account of one science teacher's participation in a teacher workshop in which teachers learned about volcanic development, types of eruption, geomorphology, plate tectonics, volcano monitoring, and hazards created by volcanoes by examining Mt. St. Helens. Provides a graphic identifying volcanoes active since 1975. (MDH)

  5. 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.

  6. 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

  7. Mt. St. Helens

    NASA Technical Reports Server (NTRS)

    2001-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Figure 1 Movie

    This 3-D anaglyph image of Mt. St. Helens volcano combines the nadir-looking and back-looking band 3 images of ASTER. To view the image in stereo, you will need blue-red glasses. Make sure to look through the red lens with your left eye. Figure 1: This ASTER image of Mt. St. Helens volcano in Washington 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 image is centered at 46.2 degrees north latitude, 122.2 degrees west longitude.

    Movie: 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.

    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.

  8. 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

  9. Helene: A Plastic Model

    NASA Astrophysics Data System (ADS)

    Umurhan, O. M.; Moore, J. M.; Howard, A. D.; Schenk, P.; White, O. L.

    2014-12-01

    Helene, the Saturnian L4 Trojan satellite co-orbiting Dionne and sitting within the E-ring, possesses an unusual morphology characteristic of broad km-scale basins and depressions and a generally smooth surface patterned with streaks and grooves which are indicative of non-typical mass transport. Elevation angles do not appear to exceed 10o at most. The nature and origin of the surface materials forming these grooved patterns is unknown. Given the low surface gravity (<5mm/s2), it hard to imagine how such transport features can come about with such low grades and surface gravities. Preliminary examinations of classical linear and nonlinear mass wasting mechanisms do not appear to reproduce these curious features. A suite of hypothesis that we examine is the possibility that the fine grain material on the surface has been either (i) accreted or (ii) generated as refractory detritus resulting from sublimation of the icy bedrock, and that these materials subsequently mass-waste like a non-Newtonian highly non-linear creeping flow. Modifying the landform evolution model MARSSIM to handle two new mass-wasting mechanism, the first due to glacial-like flow via Glen's Law and the second due to plastic-like flow like a Bingham fluid, we setup and test a number of likely scenarios to explain the observations. The numerical results qualitatively indicate that treating the mass-wasting materials as a Bingham material reproduces many of the qualitative features observed. We also find that in those simulations in which accretion is concomitant with Bingham mass-wasting, the long time-evolution of the surface flow shows intermittency in the total surface activity (defined as total surface integral of the absolute magnitude of the mass-flux). Detailed analyses identify the locations where this activity is most pronounced and we will discuss these and its implications in further detail.

  10. Mount St. Helens aerosol evolution

    NASA Technical Reports Server (NTRS)

    Oberbeck, V. R.; Farlow, N. H.; Fong, W.; Snetsinger, K. G.; Ferry, G. V.; Hayes, D. M.

    1982-01-01

    Stratospheric aerosol samples were collected using a wire impactor during the year following the eruption of Mount St. Helens. Analysis of samples shows that aerosol volume increased for 6 months due to gas-to-particle conversion and then decreased to background levels in the following 6 months.

  11. Mount St. Helens aerosol evolution

    SciTech Connect

    Oberbeck, V.R.; Farlow, N.H.; Fong, W.; Snetsinger, K.G.; Ferry, G.V.; Hayes, D.M.

    1982-09-01

    Stratospheric aerosol samples were collected using a wire impactor during the year following the eruption of Mt. St. Helens. Analysis of samples show that aerosol volume increased for 6 months due to gas-to-particle conversion and then decreased to background levels in the following 6 months.

  12. Mount St. Helens aerosol evolution

    SciTech Connect

    Oberbeck, V.R.; Farlow, N.H.

    1982-08-01

    Stratospheric aerosol samples were collected using a wire impactor during the year following the eruption of Mount St. Helens. Analysis of samples shows that aerosol volume increased for 6 months due to gas-to-particle conversion and then decreased to background levels in the following 6 months.

  13. Mount Saint Helens aerosol evolution

    NASA Technical Reports Server (NTRS)

    Oberbeck, V. R.; Farlow, N. H.; Snetsinger, K. G.; Ferry, G. V.; Fong, W.; Hayes, D. M.

    1982-01-01

    Stratospheric aerosol samples were collected using a wire impactor during the year following the eruption of Mt. St. Helens. Analysis of samples shows that aerosol volume increased for 6 months due to gas-to-particle conversion and then decreased to background levels in the following 6 months.

  14. Helen Coupland 1920-2015.

    PubMed

    Coupland, Terry

    2015-07-22

    Practice nurse Helen Coupland (née Irons) was born in the Rhondda Valley in South Wales, and shared a happy childhood there with her younger brother, Ted. At 17 she became a nursing student at Llwynypia Hospital, Pontypridd, where she excelled in her studies and found her calling. PMID:26198524

  15. Continuous monitoring of Mount St. Helens Volcano

    USGS Publications Warehouse

    Spall, H.

    1980-01-01

    Day by day monitoring of the Mount St. Helens Volcano. These are four scenarios, very different scenarios, that can occur in a average week at Mount St. Helens. Ranging from eruptions of gas and to steam to eruptions of ash and pyroclastic flows to even calm days. This example of monitoring illustrates the differences from day to day volcanic activities at Mount St. Helens

  16. Mount St. Helens: the aftermath

    SciTech Connect

    Flaherty, D.C.

    1983-01-01

    During the May 18, 1980 eruption of Mount St. Helens, ash fell over a 100,000 sq mile area to the east. The Idaho studies showed that, although the ashfall altered the food chains of some forest streams, within a year they fully recovered. The effects of ashfall on lake benthic organisms are still being assessed by sediment sampling. The Montana studies reported on snow avalanche models adapted to mudflows, trophic impact of ash deposits on Montana lakes, and the volcanic ash as nutrient subsidy to sub-alpine lakes. The Oregon studies reported herring and smelt egg and larvae damage due to suspended ash. The drainage patterns in eruption debris were studied along with the filling of Columbia River berths with ash.

  17. Mt. St. Helens and Spirit Lake

    NASA Technical Reports Server (NTRS)

    2002-01-01

    high resolution 1000 pixel-wide image Snow still covered the peaks of the Cascade Ranges in mid-June when the STS-111 crew photographed Mt. St. Helens from the Space Shuttle Endeavour. From their vantage point, the crew observed blast zone from the 1980 eruption of the volcano, the mud-choked North Fork of the Toutle River, and fallen timber that still floats in rafts of logs on Spirit Lake. Continued imagery of the region will document the slow regrowth of the forests. Today, the volcano and surrounding region comprise the Mt. St. Helens National Volcanic Monument which is dedicated to research, education and recreation. For more information visit: Mount St. Helens National Volcanic Monument. Astronaut photograph STS111-371-3 was provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

  18. Reports from Science Mount St. Helens

    NASA Technical Reports Server (NTRS)

    Pollack, James B.

    1981-01-01

    The following reports describe extensive measurements of the properties of the gases and aerosols (particles) in the volcanic clouds produced by the eruptions of Mount St. Helens from March through August 1980. Volcanic material was first injected into the atmosphere on 27 March 1980. This material, as well as that introduced by subsequent eruptions during the next 2 months, was confined to the troposphere. On 18 May the first of several major explosions occurred in which some of the volcanic cloud penetrated well into the stratosphere. The nature of the volcanic activity at Mount St. Helens from the end of March through June was described.

  19. Landsat observations of Mount St. Helens

    NASA Technical Reports Server (NTRS)

    Bohn, C. G.; Bly, B. G.

    1981-01-01

    The eruption of Mount St. Helens on May 18, 1980, and subsequent destruction of approximately 593 square kilometers (229 square miles) of vegetation, clearly provided a unique opportunity for earth-oriented satellite remote sensing systems. Landsat, a relatively high resolution Multispectral Scanner (MSS) system, imaged Mount St. Helens both before and after its major eruption. Digital data have been used to create a damage assessment map and a change detection image. Several classes of timber damage and land cover modification have been developed. Acreages for each class have been tabulated.

  20. 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.

  1. 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,…

  2. 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,…

  3. 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.

  4. 30 Cool Facts about Mount St. Helens

    USGS Publications Warehouse

    Driedger, Carolyn; Liz, Westby; Faust, Lisa; Frenzen, Peter; Bennett, Jeanne; Clynne, Michael

    2010-01-01

    Commemorating the 30th anniversary of the 1980 eruptions of Mount St. Helens 1-During the past 4,000 years, Mount St. Helens has erupted more frequently than any other volcano in the Cascade Range. 2-Most of Mount St. Helens is younger than 3,000 years old (younger than the pyramids of Egypt). 3-Some Native American names that refer to smoke at the volcano include- Lawala Clough, Low-We- Lat-Klah, Low-We-Not- Thlat, Loowit, Loo-wit, Loo-wit Lat-kla, and Louwala-Clough. 4-3,600 years ago-Native Americans abandoned hunting grounds devastated by an enormous eruption four times larger than the May 18, 1980 eruption. 5-1792-Captain George Vancouver named the volcano for Britain's ambassador to Spain, Alleyne Fitzherbert, also known as Baron St. Helens. 6-1975-U.S. Geological Survey geologists forecasted that Mount St. Helens would erupt again, 'possibly before the end of the century.' 7-March 20, 1980-A magnitude 4.2 earthquake signaled the reawakening of the volcano after 123 years. 8-Spring 1980-Rising magma pushed the volcano's north flank outward 5 feet per day. 9-Morning of May 18, 1980- The largest terrestrial landslide in recorded history reduced the summit by 1,300 feet and triggered a lateral blast. 10-Within 3 minutes, the lateral blast, traveling at more than 300 miles per hour, blew down and scorched 230 square miles of forest. 11-Within 15 minutes, a vertical plume of volcanic ash rose over 80,000 feet. 12-Afternoon of May 18, 1980-The dense ash cloud turned daylight into darkness in eastern Washington, causing streetlights to turn on in Yakima and Ritzville. 13-The volcanic ash cloud drifted east across the United States in 3 days and encircled Earth in 15 days. 14-Lahars (volcanic mudflows) filled rivers with rocks, sand, and mud, damaging 27 bridges and 200 homes and forcing 31 ships to remain in ports upstream. 15-The May 18, 1980 eruption was the most economically destructive volcanic event in U.S. history. 16-Small plants and trees beneath winter snow

  5. Crossing the Divide: Helen Keller and Yvonne Pitrois Dialogue on Diversity

    ERIC Educational Resources Information Center

    Hartig, Rachel

    2007-01-01

    How do those who are living with a difference most effectively cross the cultural divide and explain themselves to mainstream society? This is a central question raised by Yvonne Pitrois in her biography of Helen Keller, titled "Une nuit rayonnante: Helen Keller" [A Shining Night: Helen Keller]. Helen Keller responded to Pitrois' book in a…

  6. Electrical impact of Mt. St. Helens

    SciTech Connect

    Stemler, G.E.; Batiste, A.R.

    1981-08-01

    Ash fallout from the Mount Saint Helens eruptions affected high-voltage transmission in a four-state area as volatile gases caused conductivity changes and corrosion. The Bonneville Power Authority (BPA) found that it was possible to maintain electric service except for a few short, localized outages. Cleaning ash from transformers and substations was the first priority. Tests were underway within 48 hours to determine ash characteristics and cleaning procedures. A summary to what happened and what was learned is presented in two lists. (DCK)

  7. Obituary: Helen Dodson Prince, 1905-2002

    NASA Astrophysics Data System (ADS)

    Lindner, Rudi Paul

    2009-01-01

    Helen Dodson Prince, a pioneer in the observation of solar flares, a pioneer in women's rise in the profession of astronomy, and a respected and revered educator of future astronomers, died on 4 February 2002 in Arlington, Virginia. Helen Dodson was born in Baltimore, Maryland, on 31 December 1905. Her parents were Helen Walter and Henry Clay Dodson. Helen went to Goucher College in nearby Towson with a full scholarship in mathematics. She turned to astronomy under the influence of a legendary teacher, Professor Florence P. Lewis, and she graduated in 1927. Funded by grants and private charity, she earned the Ph.D. in astronomy at the University of Michigan under the direction of Heber Doust Curtis in 1933. Dodson taught at Wellesley College from 1933 until 1943, when she went on leave to spend the last three years of World War II at the MIT Radiation Laboratory. She returned to Goucher after the war as professor of astronomy and mathematics, and in 1947 she came back to Michigan both as professor of astronomy and staff member of the McMath-Hulbert Observatory, of which she became associate director. In 1976 she retired from Michigan and spent her later years in Alexandria, Virginia. In 1932 Dodson held the Dean Van Meter fellowship from Goucher; in 1954 she received the Annie Jump Cannon Prize from the AAS; and in 1974 The University of Michigan honored her with its Faculty Distinguished Achievement Award. She published over 130 articles, mostly on her research specialty, solar flares. Dodson's interest in the Sun began at Michigan, although her dissertation was, like so many Michigan dissertations of the era, on stellar spectroscopy, "A Study of the Spectrum of 25 Orionis." She came to Michigan during the establishment and growth of the solar observatory at Lake Angelus, the creation of three gifted and industrious amateurs. Heber Curtis fostered the growth of the McMath-Hulbert enterprise and brought it into the University. Dodson's solar activity grew as a

  8. Helen Keller Centers for Deaf-Blind Youth and Adults.

    ERIC Educational Resources Information Center

    American Annals of the Deaf, 2003

    2003-01-01

    This listing provides directory information for the national Helen Keller Center and its 10 regional offices. The centers provide extensive evaluative and rehabilitation services to people who are deaf and blind. (CR)

  9. Lidar measurements of Mount St. Helens effluents

    NASA Technical Reports Server (NTRS)

    Mccormick, M. P.

    1982-01-01

    Lidar measurements of the worldwide movement of stratospheric aerosols produced by the 18 May 1980 eruption of Mount St. Helens are described. Ground-based and airborne measurements show that the layers below 20 km produced by this eruption moved in an easterly direction while those above 20 km moved in a westerly direction. The effluent at jet stream altitudes of 10 to 12 km circled the globe in about 16 days and the effluent at 23 km (the highest altitude recorded) circled the globe in about 56 days. Mass calculations, using backscatter-to-mass conversion models, indicate that approximately half a million metric tons of new stratospheric material were produced by this eruption. Even though this represents a 200% increase in Northern Hemispheric aerosol, no significant long-term atmospheric temperature change should occur.

  10. In the wake of Mount St Helens

    SciTech Connect

    Nania, J.; Bruya, T.E.

    1982-04-01

    On May 18, 1980, Mount St Helens, Washington State's most active volcano, erupted violently. Volcanic eruptions in recent geologic history have demonstrated tremendous environmental impact and caused significant loss of human life. Volcanic ash expelled during the eruption was deposited on much of eastern Washington and had a profound effect on local air quality. Although ash is relatively inert, analysis revealed a small but significant amount of free crystalline silica, the causative agent of silicosis. The fine particles of ash were of respirable size, and there was a remarkable increase in the volume of respiratory cases seen in emergency departments during the period of high airborne particulate levels. Numerous cases of injury indirectly related to the fall of ash were also seen. The long-term effect of exposure to this volcanic ash is unknown. A prompt, coordinated community medical response is necessary to protect the general population from the potential hazard of exposure to volcanic ash.

  11. 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. PMID:6832120

  12. A visit to Mount St. Helens

    SciTech Connect

    Meadows, D.G.

    1994-04-01

    The May 18, 1980, eruption displaced roughly 2.6 km[sup 3] of rock and devastated more than 500 km[sup 2] of forest, mostly to the north of the mountain. Trees within 10--15 km of the mountain peak were burned and uprooted. Beyond that, high winds and flying debris created a blowdown zone. Up to 150 m of rock and ice covered some areas. Accumulations of ash were measured as much as 330 km from the volcano. Mud flows choked nearby rivers and streams. Two years later, the US Congress established the 44,000-hectare Mount St. Helens National Volcanic Monument. The Act essentially directed the USDA Forest Service to allow the area to recover naturally. The paper reviews what changes the ecosystem has been going through since the eruption and the lessons learned that suggest some new resource management techniques.

  13. In the wake of Mount St Helens.

    PubMed

    Nania, J; Bruya, T E

    1982-04-01

    On May 18, 1980, Mount St Helens, Washington State's most active volcano, erupted violently. Volcanic eruptions in recent geologic history have demonstrated tremendous environmental impact and caused significant loss of human life. Volcanic ash expelled during the eruption was deposited on much of eastern Washington and had a profound effect on local air quality. Although ash is relatively inert, analysis revealed a small but significant amount of free crystalline silica, the causative agent of silicosis. The fine particles of ash were of respirable size, and there was a remarkable increase in the volume of respiratory cases seen in emergency departments during the period of high airborne particulate levels. Numerous cases of injury indirectly related to the fall of ash were also seen. The long-term effect of exposure to this volcanic ash is unknown. A prompt, coordinated community medical response is necessary to protect the general population from the potential hazard of exposure to volcanic ash. PMID:7073033

  14. Helen (Lena) Stavridou Astin (1932-2015).

    PubMed

    Harway, Michele

    2016-09-01

    This article memorializes Helen (Lena) Stavridou Astin, who died at her home October 27, 2015 after a long illness. As only the second woman to earn a doctorate in psychology at the University of Maryland, Lena opened the door for other women. Her 1969 classic book, , was the first to provide data to counteract the belief that highly educated women drop out of the labor force to concentrate on family. Within the American Psychological Association, Lena was the first chair of what became the Committee on Women in Psychology and the second president of the Division on the Psychology of Women (Division 35). She also served on several American Psychological Association governance boards. During her early years, she worked at the National Academy of Science, the Bureau of Social Science Research, and University Research Associates. (PsycINFO Database Record PMID:27571532

  15. Overview Of Mount St. Helens Volcanic Eruption

    NASA Astrophysics Data System (ADS)

    Tilling, Robert I.

    Dormant since 1857, Mount St. Helens Volcano in southwestern Washington stirred from its repose to erupt on March 27, 1980, following a week of premonitory earthquake activity. The eruption was the first in the conterminous United States since the 1914-1921 activity of Lassen Peak, California. The eruptive activity through May 17 was intermittent and relatively mild, but the accompanying seismic activity remained intense. On May 18, a catastrophic eruption, triggered by a magnitude 5.0 earthquake, produced a massive landslide/debris avalanche, a devastating lateral "blast," pyroclastic flows, mudflows, and an ash column that rose more than 20 km into the stratosphere. Winds carried the ash easterly, and more than 7 cm of ash was deposited locally in parts of eastern Washington. The landslide/debris avalanche and associated mudflows caused flooding of the Toutle and Cowlitz River valleys, which carried sediment as far as the confluence with the Columbia, where it choked off the channel to navigation. Smaller but significant explosive eruptions followed in May, June, July, August, and October, 1980, with lava domes being extruded in the crater following the June, August, and October eruptions. Subsequently in December 1980 and February 1981, lava domes were extruded without significant preceding explosive activity. Except for the latter two, each dome was partly or wholly destroyed by succeeding explosive events. Scientists expect similar activity to continue for months or years--possibly even decades. The Mount St. Helens eruptions severely tested the ability of scientists to respond swiftly and effectively in assisting public officials during a geologic disaster. At the same time, they shall continue to provide an unprecedented opportunity for the systematic investigation of volcanic phenomena, and hopefully, the insight to meet possible future eruptions there and elsewhere in the Cascade Range with equal success.

  16. Psychiatric reactions to disaster: the Mount St. Helens experience.

    PubMed

    Shore, J H; Tatum, E L; Vollmer, W M

    1986-05-01

    Following the 1980 Mount St. Helens volcanic eruption, psychiatric reactions were studied in the disaster area and in a control community. Using the new criterion-based diagnostic method for psychiatric epidemiologic research, the Diagnostic Interview Schedule, the authors found a significant prevalence of disaster-related psychiatric disorders. These Mount St. Helens disorders included depression, generalized anxiety, and posttraumatic stress reaction. There was a progressive "dose-response" relationship in the comparison of control, low-exposure, and high-exposure groups. The dose-response pattern occurred among both the bereaved and the property-loss victims. PMID:3963245

  17. Mineral dust transport toward Hurricane Helene (2006)

    NASA Astrophysics Data System (ADS)

    Schwendike, Juliane; Jones, Sarah C.; Vogel, Bernhard; Vogel, Heike

    2016-05-01

    This study investigates the transport of mineral dust from its source regions in West Africa toward the developing tropical cyclone Helene (2006) and diagnoses the resulting properties of the air influencing the tropical cyclonegenesis. The model system COSMO-ART (Consortium for Small-Scale Modelling-Aerosols and Reactive Trace gases) in which the emission and transport of mineral dust as well as the radiation feedback are taken into account, was used. The emission of mineral dust between 9 and 14 September 2006 occurred in association with the relatively strong monsoon flow and northeasterly trade winds, with gust fronts of convective systems over land, and with the Atlantic inflow. Additionally, increased surface wind speed was linked to orographical effects at the Algerian Mountains, Atlas Mountains, and the Hoggar. The dust, as part of the Saharan air layer, is transported at low levels by the monsoon flow, the Harmattan, the northeasterly trade winds, and the monsoon trough, and is transported upward in the convergence zone between Harmattan and monsoon flow, in the baroclinic zone along the West African coastline, and by convection. At around 700 hPa the dust is transported by the African easterly jet. Dry and dust-free air is found to the north-northwest of the developing tropical depression due to descent in an anticyclone. Based on the model data, it was possible to distinguish between dry (from the anticyclone), dry and dusty (from the Harmattan and northeasterly trade winds), and dusty and moist air (from the monsoon flow and in the tropical depression due to convection).

  18. Boise Inc. St. Helens Paper Mill Achieves Significant Fuel Savings

    SciTech Connect

    Not Available

    2008-05-01

    This case study describes how the Boise Inc. paper mill in St. Helens, Oregon, achieved annual savings of approximately 154,000 MMBtu and more than $1 million after receiving a DOE Save Energy Now energy assessment and implementing recommendations to improve the efficiency of its steam system.

  19. Boise Inc. St. Helens Paper Mill Achieves Significant Fuel Savings

    SciTech Connect

    2008-05-01

    This case study describes how the Boise Inc. paper mill in St. Helens, Oregon, achieved annual savings of approximately 154,000 MMBtu and more than $1 million. This was accomplished after receiving a DOE Save Energy Now energy assessment and implementing recommendations to improve the efficiency of its steam system.

  20. Eruptions of Mount St. Helens : Past, present, and future

    USGS Publications Warehouse

    Tilling, Robert I.; Topinka, Lyn J.; Swanson, Donald A.

    1990-01-01

    Mount St. Helens, located in southwestern Washington about 50 miles northeast of Portland, Oregon, is one of several lofty volcanic peaks that dominate the Cascade Range of the Pacific Northwest; the range extends from Mount Garibaldi in British Columbia, Canada, to Lassen Peak in northern California. Geologists call Mount St. Helens a composite volcano (or stratovolcano), a term for steepsided, often symmetrical cones constructed of alternating layers of lava flows, ash, and other volcanic debris. Composite volcanoes tend to erupt explosively and pose considerable danger to nearby life and property. In contrast, the gently sloping shield volcanoes, such as those in Hawaii, typically erupt nonexplosively, producing fluid lavas that can flow great distances from the active vents. Although Hawaiian-type eruptions may destroy property, they rarely cause death or injury. Before 1980, snow-capped, gracefully symmetrical Mount St. Helens was known as the "Fujiyama of America." Mount St. Helens, other active Cascade volcanoes, and those of Alaska form the North American segment of the circum-Pacific "Ring of Fire," a notorious zone that produces frequent, often destructive, earthquake and volcanic activity.

  1. Pulmonary toxicity of Mount St. Helens volcanic ash

    SciTech Connect

    Sanders, C.L.; Gelman, A.; Conklin, A.; Adee, R.R.

    1980-01-01

    The distribution, clearance, translocation and pathobiology of intratracheally instilled (IT) Mount St. Helens volcanic ash samples are discussed and compared with NIOSH quartz and Ritzville sandy loam samples as positive controls and saline as a negative control. Comparisons are also made with similar studies in rats using chrysotile asbestos, beryllium oxide and cadmium oxide.

  2. Learning from Mount St. Helens: Catastrophic Events as Educational Opportunities.

    ERIC Educational Resources Information Center

    Anderson, Jeremy

    1987-01-01

    Maintains that the study of catastrophic events should be given temporary precedence over the normal curriculum in order to help students understand the causes, consequences, and recovery alternatives, deal with trauma, and allay fear of recurrence and feelings of helplessness. Uses the May 1980 eruption of Mount St. Helens to demonstrate how…

  3. Mount St. Helens related aerosol properties from solar extinction measurements

    SciTech Connect

    Michalsky, J.J.; Kleckner, E.W.; Stokes, G.M.

    1980-11-01

    The optical extinction due to the introduction of aerosols and aerosol-precursors into the troposphere and stratosphere during the major eruptive phase of Mount St. Helens, Washington, is quantified. The concentration is on the two-week period centered on the major eruption of 22 July 1980. (ACR)

  4. Mt. St. Helens Seen Close Up on May 18.

    ERIC Educational Resources Information Center

    Stoffel, Dorothy B.; Stoffel, Keith L.

    1980-01-01

    Describes eruption steps in Mt. St. Helens' top surface deformation: constant shaking of earthquakes, minor steaming from vents, and sudden catastrophic eruption. Explosions caused black projectile-laden ash clouds, vertical white steam clouds, and vertical gray ash-laden clouds. (SK)

  5. Blind Rage: An Open Letter to Helen Keller

    ERIC Educational Resources Information Center

    Kleege, Georgina

    2007-01-01

    In a letter addressed to Helen Keller, the author discusses the frustrations of being blind in the modern-day world. She reflects on the seeming pettiness of her complaints next to the difficulties Keller would have faced, especially given all of the new technologies and accommodations available to the blind. She wonders how Keller dealt with her…

  6. Learning Center Guide; Helene Fuld School of Nursing.

    ERIC Educational Resources Information Center

    Rabkin, Frieda H.

    For students at the Helene Fuld School of Nursing, Brooklyn, New York, a guide is provided to services of the school Learning Center. Noncirculating materials are listed and described, including reference books, reserve materials, magazines, the vertical file, and audiovisuals. Borrowing rules and fines are discussed. A guide is provided to the…

  7. Stereo Pair, Mount St Helens, Washington State

    NASA Technical Reports Server (NTRS)

    2002-01-01

    On May 18, 1980, Mount St. Helens catastrophically erupted, causing the worst volcanic disaster in the recorded history of the United States. An earthquake shook loose the northern flank of the volcano, and about 2.8 cubic kilometers (0.67 cubic miles) of rock slid downslope in the world's largest recorded landslide. The avalanche released pressure on the volcano and unleashed a huge explosion, which was directed generally northward. The mountain ultimately lost 227 meters (1314 feet) of its height and devastated about 600 square kilometers (230 square miles) of forest.

    This stereoscopic view combines a Landsat satellite image with a Shuttle Radar Topography Mission elevation model to show the volcanic crater and most of the zone of devastation. Areas now relatively devoid of vegetation appear bright. Note the landslide debris clogging the northern drainages and forming natural dams (or enlarging previously existing ones). Also note the volcanic dome built up within the crater, and the extensive floating debris still present on Spirit Lake (northeast of the crater) 12 years after the eruption.

    This stereoscopic image was generated by draping a Landsat satellite image over a Shuttle Radar Topography Mission digital elevation model. Two differing perspectives were then calculated, one for each eye. They can be seen in 3-D by viewing the left image with the right eye and the right image with the left eye (cross-eyed viewing or by downloading and printing the image pair and viewing them with a stereoscope. When stereoscopically merged, the result is a vertically exaggerated view of Earth's surface in its full three dimensions.

    Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter (98-foot) resolution of most Landsat images and will substantially help in analyzing the large and growing Landsat image archive, managed by the U.S. Geological Survey (USGS).

    Elevation data used in this image was

  8. Anaglyph, Mount St Helens, Washington State

    NASA Technical Reports Server (NTRS)

    2002-01-01

    On May 18, 1980, Mount St. Helens catastrophically erupted, causing the worst volcanic disaster in the recorded history of the United States. An earthquake shook loose the northern flank of the volcano, and about 2.8 cubic kilometers (0.67 cubic miles) of rock slid downslope in the world's largest recorded landslide. The avalanche released pressure on the volcano and unleashed a huge explosion, which was directed generally northward. The mountain ultimately lost 227 meters (1314 feet) of its height and devastated about 600 square kilometers (230 square miles) of forest.

    This anaglyph combines a Landsat satellite image with a Shuttle Radar Topography Mission elevation model to show the volcanic crater and most of the zone of devastation. Areas now relatively devoid of vegetation appear bright. Note the landslide debris clogging the northern drainages and forming natural dams (or enlarging previously existing ones). Also note the volcanic dome built up within the crater, and the extensive floating debris still present on Spirit Lake (northeast of the crater) 12 years after the eruption.

    The stereoscopic effect of this anaglyph was created by first draping a Landsat satellite image over a digital elevation data from the Shuttle Radar Topography Mission (SRTM), and then generating two differing perspectives, one for each eye. When viewed through special glasses, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and cover the right eye with a blue filter.

    Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter (98-foot)resolution of most Landsat images and will substantially help in analyzing the large and growing Landsat image archive, managed by the U.S. Geological Survey (USGS).

    Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space

  9. 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.

  10. Small particles in plumes of Mount St. Helens

    NASA Technical Reports Server (NTRS)

    Rose, W. I.; Chuan, R. L.; Woods, D. C.

    1982-01-01

    Particles in the size range 0.1-25 microns were sampled by aircraft carrying a quartz crystal microcascade in the Mount St. Helens plume on three dates in August and September 1980. Two of the sampling dates represented 'typical' emissions of the volcano between plinian eruptions. One sampling flight was made 1-4 hours before the small plinian eruption of August 7, 1980 when the plume had become discontinuous and visibly darker. The plume sampled on August 7, before the eruption, contained mainly approximately 2-micron diameter silicic glass particles, fragments of the Mount St. Helens magma. The typical plumes sampled on September 22 and August 6 had much smaller concentrations of particles, trimodal size distributions with peaks at 10, 0.4, and 0.1 microns. The particles were largely nonsilicate and apparently represented Cu-Zn oxide (10 micron peak), Al sulfate, chloride, and oxide, and sulfuric acid (smallest size peak).

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

    NASA Astrophysics Data System (ADS)

    Brugman, M. M.; Post, A.

    The cataclysmic eruption of Mount St. Helens May 18, 1980, removed 2.9 sq/km 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 recrystallization of snow and ice surviving on Mount St. Helens could cause and lubricate mud flows and generate outburst floods.

  12. Deformation monitoring at mount st. Helens in 1981 and 1982.

    PubMed

    Chadwick, W W; Swanson, D A; Iwatsubo, E Y; Heliker, C C; Leighley, T A

    1983-09-30

    For several weeks before each eruption of Mount St. Helens in 1981 and 1982, viscous magma rising in the feeder conduit inflated the lava dome and shoved the crater floor laterally against the immobile crater walls, producing ground cracks and thrust faults. The rates of deformation accelerated before eruptions, and thus it was possible to predict eruptions 3 to 19 days in advance. Lack of deformation outside the crater showed that intrusion of magma during 1981 and 1982 was not voluminous. PMID:17759008

  13. Deformation monitoring at Mount St. Helens in 1981 and 1982

    USGS Publications Warehouse

    Chadwick, W.W., Jr.; Swanson, D.A.; Iwatsubo, E.Y.; Heliker, C.C.; Leighley, T.A.

    1983-01-01

    For several weeks before each eruption of Mount St. Helens in 1981 and 1982, viscous magma rising in the feeder conduit inflated the lava dome and shoved the crater floor laterally against the immobile crater walls, producing ground cracks and thrust faults. The rates of deformation accelerated before eruptions, and thus it was possible to predict eruptions 3 to 19 days in advance. Lack of deformation outside the crater showed that intrusion of magma during 1981 and 1982 was not voluminous.

  14. The Challenge of Advocacy: The Different Voices of Helen Keller and Burton Blatt.

    ERIC Educational Resources Information Center

    Smith, J. David

    1997-01-01

    Comparison of the different advocacy roles of Helen Keller and Burton Blatt finds that Helen Keller's role supports the belief in miracles resulting from unconditional and sustained commitments, whereas Burton Blatt's role illustrates the value of a commitment to human rights and human dignity regardless of any expectation of productivity or…

  15. Friendly Letters on the Correspondence of Helen Keller, Anne Sullivan, and Alexander Graham Bell.

    ERIC Educational Resources Information Center

    Blatt, Burton

    1985-01-01

    Excerpts from the letters between Alexander Graham Bell and Anne Sullivan and Helen Keller are given to illustrate the educational and personal growth of Helen Keller as well as the educational philosophy of Bell regarding the education of the deaf blind. (DB)

  16. Isolation and Analysis of Bacteria in Recreational Waters of the Chattahoochee River, Helen, GA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Helen is a tourism destination in the Appalachian Mountains. A popular activity during warm weather is tubing in the Chattahoochee River. This study was to determine the variety of bacteria in the Chattahoochee River in Helen, GA. Eight samples were collected during a 5km tubing trip down the Chatta...

  17. Helene: The Face that Launched a Thousand Slips

    NASA Astrophysics Data System (ADS)

    Moore, J. M.; Howard, A. D.; Schenk, P.; Thomas, P. C.

    2013-12-01

    Helene, (~17.6 km mean radius) is a L4 Trojan co-orbital of Saturn's moon Dione. Its hemisphere features an unusual morphology consisting of broad depressions and a generally smooth surface patterned with streaks and grooves. The streaks appear to be oriented down-gradient, as are the grooves. This pattern suggests intensive mass-wasting as a dominant process on the leading hemisphere. Kilometer-scale impact craters are very sparse on the leading hemisphere other than the degraded km-scale basins defining the overall satellite shape, and many small craters have a diffuse appearance suggesting ongoing mass wasting. Thus mass wasting must dominate surface-modifying processes at present. In fact, the mass wasting appears to have been sufficient in magnitude to narrow the divides between adjacent basins to narrow septa, similar, but in lower relief, to the honeycomb pattern of Hyperion. The prominent groves occur primarily near topographic divides and appear have cut into a broad, slightly lower albedo surface largely conforming to the present topography but elevated a few meters above the smooth surfaces undergoing mass wasting flow. Low ridges and albedo markings on the surface suggest surface flow of materials traveling up to several kilometers. Diffusive mass wasting produces smooth surfaces - such a pattern characterizes most of the low-lying surfaces. The grooves, however, imply that the transport process is advective at those locations where they occur, that is, erosion tends to concentrate along linear pathways separated by divides. In fact, in many places grooves have a fairly regular spacing of 125-160 m, defining a characteristic erosional scale. Several questions are prompted by the unusual morphology of Helene: 1) What is the nature of the surface materials? 2) Are the transport processes gradual or catastrophic motion from one or a few events? 3) What mechanisms drive mass wasting and groove development? 4) Have the formative processes been active in the

  18. 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.

  19. Ocular effects following the volcanic eruptions of Mount St Helens.

    PubMed

    Fraunfelder, F T; Kalina, R E; Buist, A S; Bernstein, R S; Johnson, D S

    1983-03-01

    Three hundred thirty-two ophthalmologists examined 1,523 patients with immediate ocular complaints following the 1980 eruptions of Mount St Helens. Loggers working up to 18 months in environments with high concentrations of volcanic ash were compared with a control group of loggers without volcanic ash contact. Although the ash particles acted as ocular foreign bodies, the small particles were apparently well tolerated for the most part, except for acute irritation. Patients with contact lenses or sicca syndrome had the most frequent ocular complaints. To date, no long-term ocular effects have been noted secondary to volcanic ash exposure. PMID:6830486

  20. Regenerating the blast zone of Mount St. Helens

    SciTech Connect

    Winjum, J.K.; Keatley, J.E.; Stevens, R.G.; Gutzwiler, J.R.

    1986-05-01

    On May 18, 1980 an earthquake beneath the north side of Mt. St. Helens triggered the eruption of this volcano. This eruption caused damage to 160,000 acres of forests, meadows, lakes and streams. This paper discussed the reforestation of approximately 68,000 acres of commercial forest lands owned by Weyerhaeuser Company. This five year operation was the result of the cooperation of a team of research and operations foresters. The progress was reassuring but some areas will require more time before regeneration will be complete.

  1. 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. PMID:15486253

  2. Long-wave stratospheric transmission of Mount St. Helens ejecta

    NASA Technical Reports Server (NTRS)

    Kuhn, P. M.; Haughney, L. C.; Innis, R. C.

    1981-01-01

    The NASA/Ames Research C-141 aircraft underflew the Mount St. Helens ejecta plume in Utah three days after the eruption. Upward-looking 20-40-microns on-board radiometry provided data resulting in a calculated long-wave transmission of 0.93. From this value, an optical depth of 0.073 is inferred. This value is compared with an accepted background, stratospheric infrared optical depth of 0.06. Assumptions on particle size, shortwave albedo, and thermal warming imply little surface temperature change caused by the ejecta on the third day immediately following the eruption.

  3. Long-wave stratospheric transmission of Mount St. Helens ejecta

    SciTech Connect

    Kuhn, P.M.; Haughney, L.C.; Innis, R.C.

    1981-01-01

    The NASA/Ames Research C-141 aircraft underflew the Mount St. Helens ejecta plume in Utah three days after the eruption. Upward-looking 20--40-..mu..m on-board radiometry provided data resulting in a calculated long-wave transmission of 0.93. From this value, an optical depth of 0.073 is inferred. This value is compared with an accepted background, stratospheric infrared optical depth of 0.06. Assumptions on particle size, shortwave albedo, and thermal warming imply little surface temperature change caused by the ejecta on the third day immediately following the eruption.

  4. The Face of Women's Health: Helen Rodriguez-Trias

    PubMed Central

    Wilcox, Joyce

    2002-01-01

    The American Public Health Association has announced that it will establish an award in the name of Helen Rodriguez-Trias, MD, its first Latina president, who died of lung cancer on December 27, 2002. Rodriguez-Trias, a nationally known advocate for underserved communities, was awarded the Presidential Citizens Medal by President Clinton in January 2001 for her work on behalf of children, women, people with AIDS, and the poor. This article is based on a dialogue with Rodriguez-Trias that began in September 2001 and ended December 12, 2001. PMID:11919054

  5. Aspects of child labor in Tonna's "Helen Fleetwood".

    PubMed

    Benziman, Galia

    2011-01-01

    This article explores the unique role of Charlotte Elizabeth Tonna's "Helen Fleetwood" (1841), one of the first social-problem novels, in shaping the concerns and strategies of the genre. Writing at a moment of cultural change in the attitude toward children, Tonna's Blakean vision of child labor as diabolical allows her to offer a daring critique of social institutions. Yet her political vision is inconsistent: although she redeems the working-class child's point of view and rehumanizes this figure, Tonna's staging of child labor as originating in a metaphysical, divine plan leads her to construct children's suffering as a justifiable and even desirable ethos. PMID:22213890

  6. Morphologic Evolution of the Mount St. Helens Crater Area, Washington

    NASA Technical Reports Server (NTRS)

    Beach, G. L.

    1985-01-01

    The large rockslide-avalanche that preceded the eruption of Mount St. Helens on 18 May 1980 removed approximately 2.8 cubic km of material from the summit and north flank of the volcano, forming a horseshoe-shaped crater 2.0 km wide and 3.9 km long. A variety of erosional and depositional processes, notably mass wasting and gully development, acted to modify the topographic configuration of the crater area. To document this morphologic evolution, a series of annual large-scale topographic maps is being produced as a base for comparitive geomorphic analysis. Four topographic maps of the Mount St. Helens crater area at a scale of 1:4000 were produced by the National Mapping Division of the U. S. Geological Survey. Stereo aerial photography for the maps was obtained on 23 October 1980, 10 September 1981, 1 September 1982, and 17 August 1983. To quantify topographic changes in the study area, each topographic map is being digitized and corresponding X, Y, and Z values from successive maps are being computer-compared.

  7. Fluvial sedimentation following Quaternary eruptions of Mount St. Helens, Washington

    SciTech Connect

    Janda, R.J.; Meyer, D.F

    1985-01-01

    Depositional records of convulsive volcanic events at Mount St. Helens are in many places obscured by rapid fluvial erosion and deposition close to the volcano. Some major eruptions are recorded primarily by lahars and alluvium deposited tens of kilometers away. About 35 percent of the distinctive hummocky topography of the 1980 North Fork Toutle debris avalanche deposit now resembles an alluvial fan or a braided glacial outwash plain covered with 10 m or more of alluvium. Deposits of small (20 x 10/sup 6/m/sup 3/) but damaging lahars, such as those generated in the afternoon of 18 May 1980 and on 19 March 1982, have been largely eroded away. Rivers draining rapidly eroding areas surrounding Mount St. Helens presently have sediment yields that are among the highest in the world for nonglaciated streams of comparable size. These sediment loads are capable of causing aggradation-induced flooding in populated areas along the lower Toutle and Cowlitz Rivers. Sediment retention structures and dredging have prevented such flooding. Immediately following prehistoric eruptions, however, coarse-grained volcanic alluvium was deposited in the Cowlitz River to levels more than 1 m above the 1980 mud flow inundation level. Post-1980 rapid landscape modifications and high sediment yields are noteworthy because the eruption-impact area has not yet had a major regional storm and potentially catastrophic breachings of avalanche-impounded lakes have been prevented through engineering measures.

  8. CARBON AND NITROGEN ACCUMULATION AND MICROBIAL ACTIVITY IN MOUNT ST. HELENS PYROCLASTIC SUBSTRATES AFTER 25 YEARS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lupines are important ecosystem engineers, linking above and belowground recovery of Mount St. Helens pyroclastic substrates by increasing soil organic matter and microbial activity and by influencing other biotic processes. Various soil properties were measured in samples collected from locations ...

  9. [Helen of Troy and medicine, a picture of the "Salle des Actes"].

    PubMed

    Lafont, Olivier

    2012-05-01

    The picture of the 17th century, placed upon the great chimney in the "Salle des Actes", is attributed to the painter Simon Vouet or to his co-workers. It depicts a scene extracted from Odyssey by Homer. During their way-back to Greece, after the fall and the fire of Troia, Helen and Menelaus received in Egypt the famous nepenthes from the hands of Polydamna. An inventory of the possessions of the College of Pharmacy mentioned also helenium and moly. Nepenthes was really cited by Homer as a medicine used by Helen, but helenium was only related to Helen by euphony and moly referred to a totally different part of Odyssey and was not linked at all to Helen. This study points out the importance of mythology so far as origins of Pharmacy are concerned. PMID:23045808

  10. 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.

  11. Pyroclastic flow injury. Mount St. Helens, May 18, 1980.

    PubMed

    Parshley, P F; Kiessling, P J; Antonius, J A; Connell, R S; Miller, S H; Green, F H

    1982-05-01

    Three patients who were on the periphery of the pyroclastic flow of the Mount St. Helens eruption on May 18, 1980 were treated for severe thermal and inhalation injuries. Although exposed in identical manner, two patients arrived with heavily colonized burn wounds and developed adult respiratory distress syndrome leading directly to their death, whereas the third patient, with a noncolonized burn wound and little evidence of adult respiratory distress syndrome, survived. Evidence of inhaled ash complicating various stages of adult respiratory distress syndrome was confirmed by energy dispersive roentgenographic analysis. In the Pacific Northwest, Alaska, and the Aleutian Islands, potential for further injuries of this type in even larger numbers exists. Should these occur, those who treat the victims should be aware of the potential for severe inhalation problems in addition to the obvious burns. PMID:7081562

  12. Characterization of aerosols from eruptions of Mount St. Helens

    SciTech Connect

    Chuan, R.L.; Woods, D.C.; McCormick, M.P.

    1981-01-01

    Measurements of mass concentration and size distribution of aerosols from eruptions of Mount St. Helens as well as morphological and elemental analyses were obtained between 7 April and 7 August 1980. In situ measurements were made in early phreatic and later, minor phreatomagmatic eruption clouds near the vent of the volcano and in plumes injected into the stratosphere from the major eruptions of 18 and 25 May. The phreatic aerosol was characterized by an essentially monomodal size distribution dominated by silicate particles larger than 10 micrometers in diameter. The phreatomagmatic eruption cloud was multimodal; the large size mode consisted of silicate particles and the small size modes were made up of mixtures of sulfuric acid and silicate particles. The stratospheric aerosol from the main eruption exhibited a characteristic narrow single mode with particles less than 1 micrometer in diameter and nearly all of the mass made up of sulfuric acid droplets.

  13. Evaluation of mental effects of disaster, Mount St. Helens eruption.

    PubMed

    Shore, J H; Tatum, E L; Vollmer, W M

    1986-03-01

    This psychiatric epidemiology study following the Mount St. Helens volcanic disaster revealed a significant morbidity for psychiatric disorders. The increased prevalence showed a dose response pattern in three population groups. The findings are reported as relative and attributable risk for the two exposed populations as compared to a control group. Patterns of significant risk are presented for sex, age, and for victims with pre-existing physical illness. The research utilized a new criteria-based interview schedule for the identification of psychiatric disorders. The methodology is reviewed in the context of the controversies and assumptions within the field of behavioral response to disaster stress. There are important implications for public health planning and intervention. PMID:3946730

  14. Mount St. Helens related aerosol properties from solar extinction measurements

    NASA Technical Reports Server (NTRS)

    Michalsky, J. J.; Kleckner, E. W.; Stokes, G. M.

    1982-01-01

    A network of solar radiometers, operated on the North American Continent for an average of 2 years before the first major eruption of Mount St. Helens, Washington, continues to collect direct solar data through the eruptive phase of this volcano. The radiometers collect spectral data through 12 interference filters spanning the sensitivity of the photodiode used as detector. The data are collected every 5 minutes in seven filters and every 15 minutes in five additional filters. A variant of the classical Langley method has been used to measure the optical depth of the aerosols as a function of wavelength. The network, which is the nearest station, is located some 180 kilometers east of the volcano, well within range of noticeable effects during much of the minor as well as major activity. The wavelength dependence of the aerosol-optical depth before and after the 22 July 1980 major eruption, which was well characterized because of favorable meteorological conditions is discussed.

  15. Pyroclastic flow injury. Mount St. Helens, May 18, 1980

    SciTech Connect

    Parshley, P.F.; Kiessling, P.J.; Antonius, J.A.; Connell, R.S.; Miller, S.H.; Green, F.H.

    1982-05-01

    Three patients who were on the periphery of the pyroclastic flow of the Mount St. Helens eruption on May 18, 1980 were treated for severe thermal and inhalation injuries. Although exposed in identical manner, two patients arrived with heavily colonized burn wounds and developed adult respiratory distress syndrome leading directly to their death, whereas the third patient, with a noncolonized burn wound and little evidence of adult respiratory distress syndrome, survived. Evidence of inhaled ash complicating various stages of adult respiratory distress syndrome was confirmed by energy dispersive roentgenographic analysis. In the Pacific Northwest, Alaska, and the Aleutian Islands, potential for further injuries of this type in even larger numbers exists. Should these occur, those who treat the victims should be aware of the potential for severe inhalation problems in addition to the obvious burns.

  16. Trajectories of the Mount St. Helens eruption plume

    NASA Technical Reports Server (NTRS)

    Danielsen, E. F.

    1981-01-01

    The plume of the major eruption of Mount St. Helens on May 18, 1980 penetrated 10 to 11 km into the stratosphere, attaining heights of 22 to 23 km. Wind shears rapidly converted the plume from an expanding vertical cone to a thin, slightly inclined lamina. The lamina was extruded zonally in the stratosphere as the lower part moved eastward at jet stream velocities, while the upper part slowly moved westward in the region of nonsteady transition from the westerlies to the summer stratospheric easterlies. Trajectories computed to position the NASA U-2 aircraft for sampling in the plume are described. Plume volume after 8 hours of strong volcanic emission is estimated at 2,000,000 cu km. Only about 1% of this volume is attributed to the volcano; the rest was entrained from the environment.

  17. Trajectories of the Mount St. Helens eruption plume

    SciTech Connect

    Danielsen, E.F.

    1981-01-01

    The plume of the major eruption of Mount St. Helens on 18 May 1980 penetrated 10 to 11 kilometers into the stratosphere, attaining heights of 22 to 23 kilometers. Wind shears rapidly converted the plume from expanding vertical cone to a thin, slightly inclined lamina. The lamina was extruded zonally in the stratosphere as the lower part moved eastward at jet stream velocities, while the upper part slowly moved westward in the region of nonsteady transition from the westerlies to the summer stratospheric easterlies. Trajectories computed to position the NASA U-2 aircraft for sampling in the plume are described. Plume volume after 8 hours of strong volcanic emission is estimated at 2 x 10/sup +6/ cubic kilometers. Only about 1 percent of this volume is attributed to the volcano; the rest was entrained from the environment.

  18. Mount St. Helens: A 30-year legacy of volcanism

    USGS Publications Warehouse

    Vallance, James W.; Gardner, Cynthia A.; Scott, William E.; Iverson, Richard M.; Pierson, Thomas C.

    2010-01-01

    The spectacular eruption of Mount St. Helens on 18 May 1980 electrified scientists and the public. Photodocumentation of the colossal landslide, directed blast, and ensuing eruption column—which reached as high as 25 kilometers in altitude and lasted for nearly 9 hours—made news worldwide. Reconnaissance of the devastation spurred efforts to understand the power and awe of those moments (Figure 1). The eruption remains a seminal historical event—studying it and its aftermath revolutionized the way scientists approach the field of volcanology. Not only was the eruption spectacular, but also it occurred in daytime, at an accessible volcano, in a country with the resources to transform disaster into scientific opportunity, amid a transformation in digital technology. Lives lost and the impact of the eruption on people and infrastructure downstream and downwind made it imperative for scientists to investigate events and work with communities to lessen losses from future eruptions.

  19. Mount St. Helens: A 30-Year Legacy of Volcanism

    NASA Astrophysics Data System (ADS)

    Vallance, James W.; Gardner, Cynthia A.; Scott, William E.; Iverson, Richard M.; Pierson, Thomas C.

    2010-05-01

    The spectacular eruption of Mount St. Helens on 18 May 1980 electrified scientists and the public. Photodocumentation of the colossal landslide, directed blast, and ensuing eruption column—which reached as high as 25 kilometers in altitude and lasted for nearly 9 hours—made news worldwide. Reconnaissance of the devastation spurred efforts to understand the power and awe of those moments (Figure 1). The eruption remains a seminal historical event—studying it and its aftermath revolutionized the way scientists approach the field of volcanology. Not only was the eruption spectacular, but also it occurred in daytime, at an accessible volcano, in a country with the resources to transform disaster into scientific opportunity, amid a transformation in digital technology. Lives lost and the impact of the eruption on people and infrastructure downstream and downwind made it imperative for scientists to investigate events and work with communities to lessen losses from future eruptions.

  20. Inbreeding, eugenics, and Helen Dean King (1869-1955).

    PubMed

    Ogilvie, Marilyn Bailey

    2007-01-01

    Helen Dean King's scientific work focused on inbreeding using experimental data collected from standardized laboratory rats to elucidate problems in human heredity. The meticulous care with which she carried on her inbreeding experiments assured that her results were dependable and her theoretical explanations credible. By using her nearly homozygous rats as desired commodities, she also was granted access to venues and people otherwise unavailable to her as a woman. King's scientific career was made possible through her life experiences. She earned a doctorate from Bryn Mawr College under Thomas Hunt Morgan and spent a productive career at the Wistar Institute of Anatomy and Biology in Philadelphia where she had access to the experimental subjects which made her career possible. In this paper I examine King's work on inbreeding, her participation in the debates over eugenics, her position at the Wistar Institute, her status as a woman working with mostly male scientists, and her involvement with popular science. PMID:18348398

  1. Evaluation of mental effects of disaster, Mount St. Helens eruption.

    PubMed Central

    Shore, J H; Tatum, E L; Vollmer, W M

    1986-01-01

    This psychiatric epidemiology study following the Mount St. Helens volcanic disaster revealed a significant morbidity for psychiatric disorders. The increased prevalence showed a dose response pattern in three population groups. The findings are reported as relative and attributable risk for the two exposed populations as compared to a control group. Patterns of significant risk are presented for sex, age, and for victims with pre-existing physical illness. The research utilized a new criteria-based interview schedule for the identification of psychiatric disorders. The methodology is reviewed in the context of the controversies and assumptions within the field of behavioral response to disaster stress. There are important implications for public health planning and intervention. PMID:3946730

  2. Patterns in Seismicity at Mt St Helens and Mt Unzen

    NASA Astrophysics Data System (ADS)

    Lamb, Oliver; De Angelis, Silvio; Lavallee, Yan

    2014-05-01

    Cyclic behaviour on a range of timescales is a well-documented feature of many dome-forming volcanoes. Previous work on Soufrière Hills volcano (Montserrat) and Volcán de Colima (Mexico) revealed broad-scale similarities in behaviour implying the potential to develop general physical models of sub-surface processes [1]. Using volcano-seismic data from Mt St Helens (USA) and Mt Unzen (Japan) this study explores parallels in long-term behaviour of seismicity at two dome-forming systems. Within the last twenty years both systems underwent extended dome-forming episodes accompanied by large Vulcanian explosions or dome collapses. This study uses a suite of quantitative and analytical techniques which can highlight differences or similarities in volcano seismic behaviour, and compare the behaviour to changes in activity during the eruptive episodes. Seismic events were automatically detected and characterized on a single short-period seismometer station located 1.5km from the 2004-2008 vent at Mt St Helens. A total of 714 826 individual events were identified from continuous recording of seismic data from 22 October 2004 to 28 February 2006 (average 60.2 events per hour) using a short-term/long-term average algorithm. An equivalent count will be produced from seismometer recordings over the later stages of the 1991-1995 eruption at MT Unzen. The event count time-series from Mt St Helens is then analysed using Multi-taper Method and the Short-Term Fourier Transform to explore temporal variations in activity. Preliminary analysis of seismicity from Mt St Helens suggests cyclic behaviour of subannual timescale, similar to that described at Volcán de Colima and Soufrière Hills volcano [1]. Frequency Index and waveform correlation tools will be implemented to analyse changes in the frequency content of the seismicity and to explore their relations to different phases of activity at the volcano. A single station approach is used to gain a fine-scale view of variations in

  3. Linking community and ecosystem development on Mount St. Helens.

    PubMed

    Gill, Richard A; Boie, Jennifer A; Bishop, John G; Larsen, Lindsay; Apple, Jennifer L; Evans, R David

    2006-06-01

    In the two decades following the 1980 eruption of Mount St. Helens in Washington State, the N2-fixing colonizer Lupinus lepidus is associated with striking heterogeneity in plant community and soil development. We report on differences in nutrient availability and plant tissue chemistry between older, dense patches (core) of L. lepidus and more recently established low density patches (edge). In addition, we conducted a factorial nitrogen and phosphorus fertilization experiment in core patches to examine the degree of N and P limitation in early primary succession. We found that there were no significant differences in N or P availability between core and edge L. lepidus patches during the dry summer months, although nutrient availability is very low across the landscape. In the high density patches we found lower tissue N content and higher fiber content in L. lepidus tissue than in the younger edge patches. The addition of nutrients substantially altered plant community composition, with N addition causing an increase in other forb biomass and a corresponding competition-induced decline in L. lepidus biomass. The majority of the positive biomass response came from Hypochaeris radicata. In the second year of the fertilization experiment, the addition of N significantly increased total community biomass while L. lepidus biomass declined by more than 50%. The response of every species other than L. lepidus to N additions suggests that N may be the macronutrient most limiting plant production on Mount St. Helens but that the gains in productivity were somewhat offset by a decline of the dominant species. By the third year of the experiment, L. lepidus began to increase in abundance with P addition. This result suggests co-limitation of the community by N and P. PMID:16463176

  4. The isotopic and chemical evolution of Mount St. Helens

    USGS Publications Warehouse

    Halliday, A.N.; Fallick, A.E.; Dickin, A.P.; Mackenzie, A.B.; Stephens, W.E.; Hildreth, W.

    1983-01-01

    Isotopic and major and trace element analysis of nine samples of eruptive products spanning the history of the Mt. St. Helens volcano suggest three different episodes; (1) 40,000-2500 years ago: eruptions of dacite with ??{lunate}Nd = +5, ??{lunate}Sr = -10, variable ??18O, 206Pb/204Pb ??? 18.76, Ca/Sr ??? 60, Rb/Ba ??? 0.1, La/Yb ??? 18, (2) 2500-1000 years ago: eruptions of basalt, andesite and dacite with ??{lunate}Nd = +4 to +8, ??{lunate}Sr = -7 to -22, variable ??18O (thought to represent melting of differing mantle-crust reservoirs), 206Pb/204Pb = 18.81-18.87, variable Ca/Sr, Rb/Ba, La/Yb and high Zr, (3) 1000 years ago to present day: eruptions of andesite and dacite with ??{lunate}Nd = +6, ??{lunate}Sr = -13, ??18O ???6???, variable 206Pb/204Pb, Ca/Sr ??? 77, Rb/Ba = 0.1, La/Yb ??? 11. None of the products exhibit Eu anomalies and all are LREE enriched. There is a strong correlation between 87Sr/86Sr and differentiation indices. These data are interpreted in terms of a mantle heat source melting young crust bearing zircon and garnet, but not feldspar, followed by intrusion of this crustal reservoir by mantle-derived magma which caused further crustal melting and contaminated the crustal magma system with mafic components. Since 1000 years ago all the eruptions have been from the same reservoir which has displayed a much more gradual re-equilibration of Pb isotopic compositions than other components suggesting that Pb is being transported via a fluid phase. The Nd and Sr isotopic compositions lie along the mantle array and suggest that the mantle underneath Mt. St. Helens is not as depleted as MORB sources. There is no indication of seawater involvement in the source region. ?? 1983.

  5. Catastrophic eruptions of the directed-blast type at Mount St. Helens, bezymianny and Shiveluch volcanoes

    USGS Publications Warehouse

    Bogoyavlenskaya, G.E.; Braitseva, O.A.; Melekestsev, I.V.; Kiriyanov, V. Yu; Dan, Miller C.

    1985-01-01

    This paper describes catastrophic eruptions of Mount St. Helens (1980), Bezymianny (1955-1956), and Shiveluch (1964) volcanoes. A detailed description of eruption stages and their products, as well as the quantitative characteristics of the eruptive process are given. The eruptions under study belong to the directed-blast type. This type is characterized by the catastrophic character of the climatic stage during which a directed blast, accompanied by edifice destruction, the profound ejection of juvenile pyroclastics and the formation of pyroclastic flows, occur. The climatic stage of all three eruptions has similar characteristics, such as duration, kinetic energy of blast (1017-1018 J), the initial velocity of debris ejection, morphology and size of newly-formed craters. But there are also certain differences. At Mount St. Helens the directed blast was preceeded by failure of the edifice and these events produced separable deposits, namely debris avalanche and directed blast deposits which are composed of different materials and have different volumes, thickness and distribution. At Bezymianny, failure did not precede the blast and the whole mass of debris of the old edifice was outburst only by blast. The resulting deposits, represented by the directed blast agglomerate and sand facies, have characteristics of both the debris avalanche and the blast deposit at Mount St. Helens. At Shiveluch directed-blast deposits are represented only by the directed-blast agglomerate; the directed-blast sand facies, or blast proper, seen at Mount St. Helens is absent. During the period of Plinian activity, the total volumes of juvenile material erupted at Mount St. Helens and at Besymianny were roughly comparable and exceeded the volume of juvenile material erupted at Shiveluch, However, the volume of pyroclastic-flow deposits erupted at Mount St. Helens was much less. The heat energy of all three eruptions is comparable: 1.3 ?? 1018, 3.8-4.8 ?? 1018 and 1 ?? 1017 J for

  6. Surtsey and Mount St. Helens: a comparison of early succession rates

    NASA Astrophysics Data System (ADS)

    del Moral, R.; Magnússon, B.

    2013-12-01

    Surtsey and Mount St. Helens are celebrated, but very different volcanoes. Permanent plots allow comparisons that reveal mechanisms that control succession and its rate and suggest general principles. We estimated rates from structure development, species composition using detrended correspondence analysis (DCA), changes in Euclidean distance (ED) of DCA vectors and by principal components analysis (PCA) of DCA. On Surtsey, rates determined from DCA trajectory analyses decreased as follows: gull colony on lava with sand > gull colony on lava, no sand ≫ lava with sand > sand spit > block lava > tephra. On Mount St. Helens, plots on lahar deposits near woodlands were best developed. The succession rates of open meadows declined as follows: Lupinus-dominated pumice > protected ridge with Lupinus > other pumice and blasted sites > isolated lahar meadows > barren plain. Despite the prominent contrasts between the volcanoes, common themes were revealed. Isolation restricted the number of colonists on Surtsey and to a lesser degree on Mount St. Helens. Nutrient input from outside the system was crucial. On Surtsey, seabirds fashioned very fertile substrates, while on Mount St. Helens wind brought a sparse nutrient rain, then Lupinus enhanced fertility to promote succession. Environmental stress limits succession in both cases. On Surtsey, bare lava, compacted tephra and infertile sands restrict development. On Mount St. Helens, exposure to wind and infertility slow succession.

  7. Surtsey and Mount St. Helens: a comparison of early succession rates

    NASA Astrophysics Data System (ADS)

    del Moral, R.; Magnússon, B.

    2014-04-01

    Surtsey and Mount St. Helens are celebrated but very different volcanoes. Permanent plots allow for comparisons that reveal mechanisms that control succession and its rate and suggest general principles. We estimated rates from structure development, species composition using detrended correspondence analysis (DCA), changes in Euclidean distance (ED) of DCA vectors, and by principal components analysis (PCA) of DCA. On Surtsey, rates determined from DCA trajectory analyses decreased as follows: gull colony on lava with sand > gull colony on lava, no sand ≫ lava with sand > sand spit > block lava > tephra. On Mount St. Helens, plots on lahar deposits near woodlands were best developed. The succession rates of open meadows declined as follows: Lupinus-dominated pumice > protected ridge with Lupinus > other pumice and blasted sites > isolated lahar meadows > barren plain. Despite the prominent contrasts between the volcanoes, we found several common themes. Isolation restricted the number of colonists on Surtsey and to a lesser degree on Mount St. Helens. Nutrient input from outside the system was crucial. On Surtsey, seabirds fashioned very fertile substrates, while on Mount St. Helens wind brought a sparse nutrient rain, then Lupinus enhanced fertility to promote succession. Environmental stress limits succession in both cases. On Surtsey, bare lava, compacted tephra and infertile sands restrict development. On Mount St. Helens, exposure to wind and infertility slow succession.

  8. Inclusions in Mount St. Helens dacite erupted from 1980 through 1983

    USGS Publications Warehouse

    Heliker, C.

    1995-01-01

    Inclusions of plutonic, metavolcanic and volcanic rocks are abundant in dacite pumice and lava from the 1980-1986 eruption sequence at Mount St. Helens. Point counts of inclusions exposed in talus blocks from the dome from 1980 through 1983 show that inclusions form approximately 3.5 vol.% of the lava. Eighty-five percent of the inclusions are medium-grained gabbros. The gabbroic inclusions are of four distinct type. The most abundant type is laminated gabbronorite. Various types of gabbroic inclusions, including the laminated gabbronorite, are common in Mount St. Helens lavas of approximately the last 3000 years. This coincides with the interval in which Mount St. Helens first erupted basalt and basaltic andesite lavas. These observations, together with the fact that the gabbroic inclusions are compositionally unlike any of the Tertiary intrusive rocks in the Mount St. Helens area, strongly suggest that the inclusions are related to the introduction of basalt to the Mount St. Helens magmatic system. -from Author

  9. The "Unsavory Researches" of Helen Campbell: A 19th-Century Journalist's Investigation of Urban Women's Poverty.

    ERIC Educational Resources Information Center

    Henry, Susan

    In 1886, the New York "Tribune" ran a series of articles by Helen Campbell, "The Prisoners of Poverty," which investigated the sufferings of working women in New York's slums. Initially a fiction and housekeeping writer, Helen Campbell's home economics orientation first pointed her toward the problems of the poor. In the late 1870s, she wrote a…

  10. Geologic Map of the Helen Planitia Quadrangle (V-52), Venus

    USGS Publications Warehouse

    Lopez, Ivan; Hansen, Vicki L.

    2008-01-01

    The Magellan spacecraft orbited Venus from August 10, 1990, until it plunged into the Venusian atmosphere on October 12, 1994. Magellan Mission objectives included (1) improving the knowledge of the geological processes, surface properties, and geologic history of Venus by analysis of surface radar characteristics, topography, and morphology and (2) improving the knowledge of the geophysics of Venus by analysis of Venusian gravity. The Helen Planitia quadrangle (V-52), located in the southern hemisphere of Venus between lat 25 deg S. and 50 deg S. and between long 240 deg E. and 270 deg E., covers approximately 8,000,000 km2. Regionally, the map area is located at the southern limit of an area of enhanced tectonomagmatic activity and extensional deformation, marked by a triangle that has highland apexes at Beta, Atla, and Themis Regiones (BAT anomaly) and is connected by the large extensional belts of Devana, Hecate, and Parga Chasmata. The BAT anomaly covers approximately 20 percent of the Venusian surface.

  11. Airborne radiological sampling of Mount St. Helens plumes

    SciTech Connect

    Andrews, V.E.

    1981-04-01

    Particulate and gaseous samples for radiologial analyses were collected from the plumes created by eruptions of Mount St. Helens. The sampling aircraft and equipment used are routinely employed in aerial radiological surveillance at the Nevada Test Site by the Environmental Protection Agency's Environmental Monitoring Systems Laboratory in Las Vegas, Nevada. An initial sample set was collected on April 4, 1980, during the period of recurring minor eruptions. Samples were collected again on May 19 and 20 following the major eruption of May 18. The Environmental Protection Agency's Office of Radiation Programs analyzed the samples for uranium and thorium isotopes, radium-226, lead-210, polonium-210, and radon-222. Other laboratories analyzed samples to determine particle size distribution and elemental composition. The only samples containing radioactivity above normal ambient levels were collected on May 20. Polonium-210 concentrations in the plume, determined from a sample collected between 5 and 30 km from the crater, were approximately an order of magnitude above background. Radon-222 concentrations in samples collected from the plume centerline at a distance of 15 km averaged approximately four times the average surface concentrations. The small increases in radioactivity would cause no observable adverse health effects.

  12. Pulmonary response to Mount St. Helens' volcanic ash.

    PubMed

    Vallyathan, V; Mentnech, M S; Tucker, J H; Green, F H

    1983-04-01

    The pulmonary response to a sedimented sample of Mount St. Helens' volcanic ash from the first eruption was studied at 1, 7, 28, 90, and 180 days postintratracheal administration of 1 or 10 mg of ash in specific-pathogen-free rats. One day administration of volcanic ash all animals exhibited a marked inflammatory cell response centered on respiratory bronchioles in which polymorphonuclear leukocytes predominated. At 7 days the reaction was characterized by mononuclear cellular infiltrates. The macrophages within the respiratory bronchioles and alveoli contained intracytoplasmic ash particles. At 28 days the intraalveolar aggregates of mononuclear cells had condensed to form granulomas. Most of the granulomas contained foreign body-type giant cells and some showed central necrosis. The granulomas enlarged in size from 28 days until the termination of the experiment at 180 days with progressive increase in the amount of collagenous tissue. The results of these studies suggest that the volcanic ash may pose a risk for pneumoconiosis in heavily exposed human populations. PMID:6219872

  13. Mount St. Helens plume dispersion based on trajectory analyses

    NASA Technical Reports Server (NTRS)

    Danielsen, E. F.

    1982-01-01

    The major eruption of Mount St. Helens on 18 May 1980, had sufficient energy to traverse the troposphere (9 km above the mountain top) and to penetrate an additional 10 km into the stratosphere. This plume, initially quasi-vertical, rapidly acquired the horizontal momentum of the environmental winds and suffered differential rotation due to a positive speed shear in the troposphere and a negative shear in the stratosphere. Advected rapidly eastward by the undulating jet stream, the lower stratospheric portion of the plume circled the globe at an average speed of approx. 25 m s/l, reentering North America over California in early June. During the same period, the uppermost portion slowly looped over the northwestern United States and then moved westward over the northern Pacific Ocean. Thus, plume dispersion was initiated by the vertical shears of the horizontal winds which converted a nearly vertical plume to a thin, quasi-horizontal, quasi-zonal lamina. Horizontal shears then dispersed the lamina meridionally while small-scale, wave turbulent motions spread it slowly vertically.

  14. Pulmonary toxicity of Mount St. Helens volcanic ash

    SciTech Connect

    Sanders, C.L.; Conklin, A.W.; Gelman, R.A.; Adee, R.R.; Rhoads, K.

    1982-02-01

    The effects of Mount St. Helens volcanic ash, a sandy loam soil, and quartz particles on the lung and mediastinal lymph nodes of Fischer rats were studied at time intervals of up to 109 days after in tratracheal instillation of 40 mg ash, soil, or quartz in a single dose or after multiple doses of ash instilled in seven consecutive weekly doses for a total deposition of 77 mg. Quartz caused early granuloma formation, later fibrosis was also seen in lymph nodes. Volcanic ash caused an ill-defined inflammatory reaction with a few rats showing granuloma formulation, a very limited linear fibrosis, and a moderate lipoproteinosis, and lymph nodes were enlarged with numerous microgranulomas but without reticulin and collagen formation. Pulmonary reactions to soil particles were less intense but similar to those in ash- exposed animals; lymph nodes were not enlarged. No significant clearance of ash was found at 3 months after instillation. Volcanic ash produced a simple pneumoconiosis similar to what has been described for animals and humans living for prolonged periods of time in dusty desert areas of the United States.

  15. Pressure wave generated by the Mount St. Helens eruption

    SciTech Connect

    Banister, J.B.

    1984-06-20

    Histories of the air pressure wave radiated from the eruption of Mount St. Helens on May 18, 1980, were calculated for two models of the eruption cloud expansion. The first considered the wave radiated from an accelerated plane surface, while the second examined the wave radiated from an expanding hemisphere. Two histories of eruption cloud motion based on photographs were used. Peak positive overpressures were about the same for these cloud motion histories of expansion into a hemisphere was assumed. If an accelerated planar source model was used, the peak positive pressures have again about the same value in east and west direction, but values are about half in the north and south direction. Observed peak overpressures at microbarograph stations are somewhat higher than the calculated with the most marked departures at the greater surface ranges. These observed overpressures may have been about half the correct values, however. Microbarograph records show a weaker rarefaction than calculated histories or none at all. This can be explained, in part, by a lack of a real motion coherence in the slowing eruption cloud. If it is also possible the net ash cloud volume increased considerably after its vertical growth ceased and weakened the negative phase as well as lengthening the positive phase.

  16. Measurements of SO2 in the Mount St. Helens debris

    NASA Technical Reports Server (NTRS)

    Kerr, J. B.; Evans, F. J.; Mateer, C. L.

    1982-01-01

    Routine measurements of ozone and SO2 are made with the Dobson and Brewer spectrophotometers at the Atmospheric Environment Service in Downsview Ontario. On May 20 and 21, 1980, large values of column SO2 were observed with both spectrophotometers at the time of passage of the Mount St. Helens debris. Enhanced SO2 values were first observed at 1800Z on May 20. The maximum column amount of SO2 measured was 0.06 cm at 2200 Z. On May 21, SO2 values slowly decreased from 0.03 cm at 1100 Z cm to 0.01 cm at 2000Z. Typical SO2 amounts due to pollution at the Downsview site are approximately 0.003 to 0.005 cm. At the same time of maximum SO2 enhancement, both Dobson and Brewer spectrophotometers measured a 0.040 cm decrease of total ozone. It is not clear whether the decrease of total ozone was caused by the volcanic cloud or natural ozone variability. Air mass trajectories indicate that the altitude of the debris cloud, which passed over Downsview at the time, was between 10 km and 12 km.

  17. Physical and chemical characteristics of Mount St. Helens airborne debris

    NASA Technical Reports Server (NTRS)

    Sedlacek, W. A.; Heiken, G. H.; Mroz, E. J.; Gladney, E. S.; Perrin, D. R.; Leifer, R.; Fisenne, I.; Hinchliffe, L.; Chuan, R. L.

    1982-01-01

    Tephra and aerosols from the May 18, 1980 eruption of Mount St. Helens, Washington were sampled in the lower stratosphere with a WB-57F aircraft. The main body of the plume was intercepted over western Kansas on May 20, 48 hours after the eruption, at an altitude of 15.2 km. Concentrations on filter samples were 26 ng of SO4(-2) of air and 579 ng of ash/g of air. Angular glass pyroclasts ranged in size from 0.5 to 10 microns, with a mean grain of 2 microns. Samples collected at altitudes of 16.7 and 12.5 km had only traces of SO4(-2) and ash. A second flight was flown, 72 hours after the eruption, on May 21. From north Texas to central Wyoming, at an altitude of 15.2 km less than 0.5 to 38 ng of ash/g of air and 1.0 to 2.2 ng of SO4(-2)/g of air were sampled. At an altitude of 18.3 km, from central Wyoming to NW New Mexico, the plume density and character were variable.

  18. Early succession on lahars spawned by Mount St. Helens.

    PubMed

    Del Moral, R

    1998-06-01

    The effects of isolation on primary succession are poorly documented. I monitored vegetation recovery on two Mount St. Helens lahars (mud flows) with different degrees of isolation using contiguous plots. Seventeen years after the eruption, species richness was stable, but cover continued to increase. That isolation affects community structure was confirmed in several ways. The dominance hierarchies of the lahars differed sharply. Detrended correspondence analysis on Lahar I showed a trend related to distance from an adjacent woodland, whereas vegetation on Lahar II was relatively homogeneous. Spectra of growth forms and dispersal types also differed. Lahar I was dominated by species with modest dispersal ability, while Lahar II was dominated by species with better dispersal. Variation between plots should decline through time, a prediction confirmed on Lahar II. Lahar I remained heterogeneous despite having developed significantly higher cover. Here, the increasing distance from the forest has prevented plots from becoming more homogeneous. At this stage of early primary succession, neither lahar is converging towards the species composition of adjacent vegetation. This study shows that isolation and differential dispersal ability combine to determine initial vegetation structure. Stochastic effects resulting from dispersal limitations may resist the more deterministic effects of competition that could lead to floristic convergence. PMID:21684966

  19. Ice Nucleus Characteristics of Mount St. Helens Effluents

    SciTech Connect

    Schnell, R.C.; Pueschel, R.F.; Wellman, D.L.

    1982-12-20

    Aerosols were studied in situ and captured on membrane filters from an aircraft flown around Mount St. Helens during its phreatic period in April 1980. Bulk samples of volcanic ash were collected at ground level 120 km downwind on May 19, 1980 and reaerosolized in a laboratory in ash cloud simulation studies. The aerosol and/or ash samples were tested for ice nucleus (IN) activity using four different IN measurement systems (NCAR acoustical counter, bulk drop freezing, NCAR dynamic thermal diffusion chamber, and filter drop freezing). Although threshold IN activity was observed at -8/sup 0/C in bulk ash, in aerosols there were few IN active at temperatures warmer than -12/sup 0/C. At -12/sup 0/C, IN concentrations were less than 0.4 l/sup -1/ (400 m/sup -3/) even when the aerosol concentrations were as high as 3000 ..mu..g m/sup -3/. At aerosol concentrations of 500 ..mu..g m/sup -3/ and less, the IN content of the ash was below background threshold temperatures of -18/sup 0/C.

  20. SAGE measurements of Mount St. Helens volcanic aerosols

    NASA Technical Reports Server (NTRS)

    Kent, G. S.

    1982-01-01

    The SAGE satellite system was used to make measurements on the optical extinction produced by stratospheric aerosols from the Mount St. Helens eruption. Two periods of observation were analyzed. In the first period (May 21 to 31, 1980), SAGE moved southward from latitude 60 N, and crossed the United States approximately one week after the May 18th eruption. Enhancements in stratospheric extinction were confined to latitudes between about 55 N and 25 N and longitudes between 10 W and 140 W. Individual layers were observed up to altitudes of 23 km. The geographical location of these layers corresponded closely to that expected on the basis of high-altitude meteorological data. During June and much of July, SAGE was, by reason of its geographical position and other orbital characteristics, unable to make further measurements on the northern hemisphere. Between July 19th and August 12th a second southward pass over the northern hemisphere occurred and further observations were made. The volcanic aerosol in the stratosphere was now found to be widely distributed over the hemisphere, the maximum concentrations being north of 50 N. The aerosol showed considerable inhomogeneity and had reached as far south as 15 N but little, if any, had crossed the equator into the southern hemisphere. Individual layers at different heights were still distinguishable. The total stratospheric aerosol loading on this occasion appeared to be greater than in May and corresponded to an increase in global stratospheric mass of between 50 and 100 percent.

  1. Reestablishment of endogonaceae on Mount St. Helens: survival of residuals

    SciTech Connect

    Allen, M.F.; MacMahon, J.A.; Andersen, D.C.

    1984-01-01

    The 18 May 1980 eruption of Mount St. Helens resulted in the burial of relatively well developed soils under variable depths of sterile tephra and ash. During summer 1982, we examined a series of sites and estimated the numbers of spores of Endogonaceae that had been transported from the buried soil to the new ground surface by either abiotic or biotic vectors. There was no difference between spore counts of Endogone spp. or Glomus spp. in the buried soils of forests and clear-cuts; spores were rare in the tephra at any site. In areas featuring less than or equal to 50 cm of tephra, spores were transported to the surface by gophers (in previous clear-cut areas) and by ants (in previous forest and clear-cut habitats). In the Pumice Plain, an area devoid of gophers and ants, erosion exposed spores to the surface. We found no evidence to suggest that endogonaceous fungi grow back up root systems from buried horizons. We hypothesize that small-scale perturbations (erosion, gopher and ant mounds) following the major volcanic disturbance may drive succession by exposing buried mycorrhizal and decomposer fungi. 26 references, 2 figures, 3 tables.

  2. Analysis of Mount St. Helens ash from optical photoelectric photometry

    NASA Technical Reports Server (NTRS)

    Cardelli, J. A.; Ackerman, T. P.

    1983-01-01

    The optical properties of suspended dust particles from the eruption of Mt. St. Helens on July 23, 1980 are investigated using photoelectric observations of standard stars obtained on the 0.76-m telescope at the University of Washington 48 hours after the eruption. Measurements were made with five broad-band filters centered at 3910, 5085, 5480, 6330, and 8050 A on stars of varying color and over a wide range of air masses. Anomalous extinction effects due to the volcanic ash were detected, and a significant change in the wavelength-dependent extinction parameter during the course of the observations was established by statistical analysis. Mean particle size (a) and column density (N) are estimated using the Mie theory, assuming a log-normal particle-size distribution: a = 0.18 micron throughout; N = 1.02 x 10 to the 9th/sq cm before 7:00 UT and 2.33 x 10 to the 9th/sq cm after 8:30 UT on July 25, 1980. The extinction is attributed to low-level, slowly migrating ash, possibly combined with products of gas-to-particle conversion and coagulation.

  3. Improving the intensity of the HELEN Laser at AWE

    NASA Astrophysics Data System (ADS)

    Hopps, Nicholas; Nolan, Jonathan; Girling, Mark; Kopec, Maria; Harvey, Ewan

    2005-04-01

    The HELEN laser is a three-beam, large aperture Nd:glass laser, used for plasma physics studies at the Atomic Weapons Establishment in the UK. Two of the beams nominally deliver 500 J each in 1 ns at the second harmonic (527 nm). The third beam, the "backlighter", has recently been upgraded to operate as a chirped pulse amplification system and it now routinely delivers 70 J to target in 500 fs. Optimal focal spot performance is achieved using a closed-loop adaptive optics system, which ensures good wavefront characteristics, irrespective of whether previous firing of the amplifiers has induced refractive index variations in the laser glass. The system uses a 32 element bimorph mirror with 98 mm aperture, roughly half way through the laser chain. A Shack-Hartman wavefront sensor, positioned at the output of the laser is the diagnostic used to provide feedback to the deformable mirror. Correction of the static and slowly varying aberrations on the beam has been demonstrated. The fast aberrations induced during the flashlamp discharge have been evaluated. The improved focal spot characteristics result in an intensity on target of significantly greater than 1019 Wcm-2.

  4. High accuracy EOS experiments using the AWE HELEN laser

    NASA Astrophysics Data System (ADS)

    Rothman, S. D.; Evans, A. M.

    1998-07-01

    A knowledge of a material's equation-of-state (EOS) is essential for hydrodynamic calculations. Although laser experiments investigate the pressure range between those attainable by gas guns (10Mbar) where no other data exist, it is still advantageous to obtain high accuracy data to discriminate between EOS models which have been compared with gas gun and UGT data to a few percent in pressure. The AWE HELEN laser is being used to obtain high pressure Hugoniot data by the impedance match method. Indirect drive generates pressures up to 10Mbar in the aluminium reference material. Shock velocities are obtained by observing the visible light emitted on break-out from the surface of the target using optical streak cameras. Experiments have been performed on copper and brominated plastic. Attention to target fabrication and metrology, diagnostic calibration, shock uniformity and attenuation and data analysis have enabled us to measure shock velocities to an accuracy of ˜1%.

  5. High Accuracy EOS Experiments Using the AWE HELEN Laser.

    NASA Astrophysics Data System (ADS)

    Rothman, S. D.; Evans, A. M.

    1997-07-01

    A knowledge of a material's equation-of-state (EOS) is essential for hydrodynamic calculations. Although laser experiments investigate the pressure range between those attainable by gas guns (10Mbar) where no other data exist, it is still advantageous to obtain high accuracy data to discriminate between EOS models which have been compared with gas gun and UGT data to a few percent in pressure. The AWE HELEN laser is being used to obtain high pressure Hugoniot data by the impedance match method. Indirect drive generates pressures up to 10Mbar in the aluminium reference material. Shock velocities are obtained by observing the visible light emitted on break-out from the surface of the target using optical streak cameras.Experiments have been performed on copper and brominated plastic.Attention to target fabrication and metrology, diagnostic calibration, shock uniformity and attenuation and data analysis have enabled us to measure shock velocities to an accuracy of 1it intact.

  6. A new tree-ring date for the ``floating island'' lava flow, Mount St. Helens, Washington

    NASA Astrophysics Data System (ADS)

    Yamaguchi, David K.; Hoblitt, Richard P.; Lawrence, Donald B.

    1990-09-01

    Anomalously narrow and missing rings in trees 12 m from Mount St. Helens' “floating island” lava flow, and synchronous growth increases in trees farther from the flow margin, are evidence that this andesitic flow was extruded between late summer 1799 and spring 1800 a.d., within a few months after the eruption of Mount St. Helens' dacitic layer T tephra. For ease of reference, we assign here an 1800 a.d. date to this flow. The new date shows that the start of Mount St. Helens' Goat Rocks eruptive period (1800 1857 a.d.) resembled the recent (1980 1986) activity in both petrochemical trends and timing. In both cases, an initial explosive eruption of dacite was quickly succeeded by the eruption of more mafic lavas; dacite lavas then reappeared during an extended concluding phase of activity. This behavior is consistent with a recently proposed fluid-dynamic model of magma withdrawal from a compositionally zoned magma chamber.

  7. A comparison of constituents of Mount St. Helens eruption clouds with those of some other volcanoes

    NASA Technical Reports Server (NTRS)

    Cadle, R. D.; Heidt, L.

    1982-01-01

    Gases from Mount St. Helens were collected from the eruption clouds using an airplane during the period April 2 to April 8, 1980, and were analyzed for CO2, H2, CH4, and COS. The results were of similar magnitude to those obtained from magmatic eruptions in Central America. Thus, although the eruptions were evidently largely phreatic, magmatic gases may have played a larger role in these early small eruptions than has generally been believed. Electron micrographs of ash particles collected from the Mount St. Helens eruption clouds showed that the particles were for the most part much larger than those from the Central American eruptions.

  8. Comparative physiographic diagrams of Mount St. Helens, Washington, and Crater Lake, Oregon

    USGS Publications Warehouse

    Alpha, Tau Rho; Morley, Jim M.

    1983-01-01

    These physiographic diagrams provide a visual comparison of two Cascade Range volcanoes which have had their tops destroyed in different ways -- Mount St. Helens in 1980, Mount Mazama (whose site is now occupied by Crater Lake) about 6,800 years ago. Both volcanoes are viewed from the north from 30 degrees above the horizon, with no vertical exaggeration. The ground area portrayed in each diagram is equal; the south edge of the Mount St. Helens drawing is lower than that of Crater Lake drawing because elevations drop away toward the south, whereas elevations are more constant at the north and south edges of the Crater Lake diagram. 

  9. Physical and chemical characteristics of Mt. St. Helens airborne debris

    SciTech Connect

    Sedlacek, W.A.; Heiken, G.H.; Mroz, E.J.; Gladney, E.S.; Perrin, D.R.; Leifer, R.; Fisenne, I.; Hinchliffe, L.; Chuan, R.L.

    1980-01-01

    Tephra and aerosols from the May 18, 1980 eruption of Mt. St. Helens, Washington were sampled in the lower stratosphere with a WB-57F aircraft. The main body of the plume was intercepted over western Kansas on May 20, 48 hours after the eruption, at an altitude of 15.2 km. Concentrations on filter samples were 26 ng of SO/sub 4//g of air and 579 ng of ash/g of air. Angular glass pyroclasts ranged in size from 0.5 to 10 ..mu..m, with a mean grain size of 2 ..mu..m. Samples collected at altitudes of 16.7 and 12.5 km had only traces of SO/sub 4/ and ash. A second flight was flown, 72 hours after the eruption, on May 21. From north Texas to central Wyoming, at an altitude of 15.2 km, < 0.5 to 38 ng of ash/g of air and 1.0 to 2.2 ng of SO/sub 4//g of air were sampled. At an altitude of 18.3 km, from central Wyoming to NW New Mexico, the plume density and character were variable. Glassy pyroclasts similar to those sampled on the first flight range in size from 0.5 to 4 ..mu..m dia. Trace element analysis revealed some volatile element enrichment, but far less than previously observed in the plume from St. Augustine Volcano, 1976. Values of /sup 210/Po//sup 210/Pb were 0.7 to 1.32 comparable to the secular equilibrium value of 1.0 and far less than ratios previously reported by Lambert.

  10. Air pressure waves from Mount St. Helens eruptions

    SciTech Connect

    Reed, J.W.

    1987-10-20

    Weather station barograph records as well as infrasonic recordings of the pressure wave from the Mount St. Helens eruption of May 18, 1980, have been used to estimate an equivalent explosion airblast yield for this event. Pressure amplitude versus distance patterns in various directions compared with patterns from other large explosions, such as atmospheric nuclear tests, the Krakatoa eruption, and the Tunguska comet impact, indicate that the wave came from an explosion equivalent of a few megatons of TNT. The extent of tree blowdown is considerably greater than could be expected from such an explosion, and the observed forest damage is attributed to outflow of volcanic material. The pressure-time signature obtained at Toledo, Washington, showed a long, 13-min duration negative phase as well as a second, hour-long compression phase, both probably caused by ejacta dynamics rather than standard explosion wave phenomenology. The peculiar audibility pattern, with the blast being heard only at ranges beyond about 100 km, is explicable by finite amplitude propagation effects. Near the source, compression was slow, taking more than a second but probably less than 5 s, so that it went unnoticed by human ears and susceptible buildings were not damaged. There was no damage as Toledo (54 km), where the recorded amplitude would have broken windows with a fast compression. An explanation is that wave emissions at high elevation angles traveled to the upper stratosphere, where low ambient air pressures caused this energetic pressure oscillation to form a shock wave with rapid, nearly instantaneous compression. Atmospheric refraction then returned part of this wave to ground level at long ranges, where the fast compressions were clearly audible. copyright American Geophysical Union 1987

  11. Counting, accounting, and accountability: Helen Verran's relational empiricism.

    PubMed

    Kenney, Martha

    2015-10-01

    Helen Verran uses the term 'relational empiricism' to describe situated empirical inquiry that is attentive to the relations that constitute its objects of study, including the investigator's own practices. Relational empiricism draws on and reconfigures Science and Technology Studies' traditional concerns with reflexivity and relationality, casting empirical inquiry as an important and non-innocent world-making practice. Through a reading of Verran's postcolonial projects in Nigeria and Australia, this article develops a concept of empirical and political 'accountability' to complement her relational empiricism. In Science and an African Logic, Verran provides accounts of the relations that materialize her empirical objects. These accounts work to decompose her original objects, generating new objects that are more promising for the specific postcolonial contexts of her work. The process of decomposition is part of remaining accountable for her research methods and accountable to the worlds she is working in and writing about. This is a practice of narrating relations and learning to tell better technoscientific stories. What counts as better, however, is not given, but is always contextual and at stake. In this way, Verran acts not as participant-observer, but as participant-storyteller, telling stories to facilitate epistemic flourishing within and as part of a historically located community of practice. The understanding of accountability that emerges from this discussion is designed as a contribution, both practical and evocative, to the theoretical toolkit of Science and Technology Studies scholars who are interested in thinking concretely about how we can be more accountable to the worlds we study. PMID:26630820

  12. Contingency Planning for Natural Disasters: The Mount St. Helens Experience. AIR Forum 1981 Paper.

    ERIC Educational Resources Information Center

    Burns, James A.; Concordia, Louis R.

    The effectiveness of existing contingency planning efforts at five community colleges, three colleges, and five universities during the Mount St. Helens eruptions in 1980 in Washington state was assessed. Planning efforts in the areas of institutional policy, academic policy, business office, physical plant, residence halls, financial aid, and…

  13. Mount st. Helens eruption of 18 may 1980: air waves and explosive yield.

    PubMed

    Donn, W L; Balachandran, N K

    1981-07-31

    Strong atmospheric acoustic-gravity waves were recorded by sensitive microbarographs and seismographs at large distances from the Mount St. Helens eruption of 18 May 1980. Wave signatures were similar to those of waves from large nuclear explosions. Independent theoretical and empirical analyses indicate that the explosive yield of the eruption was approximately 35 megatons. PMID:17794840

  14. Effects on the Mount St. Helens volcanic cloud on turbidity at Ann Arbor, Michigan

    SciTech Connect

    Ryznar, E.; Weber, M.R.; Hallaron, T.S.

    1981-11-01

    Measurements of turbidity were made at the University of Michigan irradiance and metorlogical measurement facility just prior to, during and after the passage of the volcanic cloud from the 18 May 1980 eruption of Mount St. Helens. They were made with a Volz sunphotometer at wavelengths of 500 and 880 nm.

  15. Evolution of Crater Glacier, Mount St. Helens, Washington, September 2006-November 2009

    USGS Publications Warehouse

    Walder, Joseph S.; Schilling, Steven P.; Sherrod, David R.; Vallance, James W.

    2010-01-01

    Lava-dome emplacement through a glacier was observed for the first time during the 2004-08 eruption of Mount St. Helens and documented using photography, photogrammetry, and geodetic measurements. Previously published reports present such documentation through September 2006; this report extends that documentation until November 2009.

  16. 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)

  17. AIRBORNE STUDIES OF THE EMISSIONS FROM THE VOLCANIC ERUPTIONS OF MOUNT ST. HELENS

    EPA Science Inventory

    The concentrations of particles less than 10 micrometers in diameter in the ash emissions from Mount St. Helens have been more than 1000 times greater than those in the ambient air. Mass loadings of particles less than 2 micrometers in diameter were generally several hundred micr...

  18. Atmospheric Effects and Potential Climatic Impact of the 1980 Eruptions of Mount St. Helens

    NASA Technical Reports Server (NTRS)

    Deepak, A. (Editor)

    1982-01-01

    Measurements and studies of the 1980 Mount St. Helens volcanic eruptions and their atmospheric effects and climatic impact are addressed. Specific areas discussed include: (1) nature and impact of volcanic eruptions; (2) in situ measurements of effluents; (3) remote sensing measurements; (4) transport and dispersion of volcanic effluents; (5) chemistry of volcanic effluents; and (6) weather and potential climate impact.

  19. INHALATION STUDIES OF MT. ST. HELENS VOLCANIC ASH IN ANIMALS. 1. INTRODUCTION AND EXPOSURE SYSTEM

    EPA Science Inventory

    Due to the lack of information on the effects of inhaled Mt. St. Helens volcanic ash and its potential interaction with sulfur dioxide (SO2), animal studies were performed to determine the acute and chronic health effects of a short-term exposure. This paper describes the inhalat...

  20. 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.

  1. 78 FR 43064 - Safety Zone; Maritime Heritage Festival Fireworks, St. Helens, OR

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-19

    ... DHS Department of Homeland Security FR Federal Register NPRM Notice of Proposed Rulemaking A... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Maritime Heritage Festival Fireworks, St... establishing a safety zone in St. Helens, OR. This safety zone is necessary to help ensure the safety of...

  2. The structure, dynamics, and chemical composition of noneruptive plumes from Mount St. Helens, 1980-1988

    USGS Publications Warehouse

    McGee, K.A.

    1992-01-01

    From May 1980 to September 1988, more than 1000 fixed-wing aircraft flights were made with a correlation spectrometer to measure the sulfur dioxide flux from Mount St. Helens volcano. These flights also provided valuable data on the structure and dynamics of noneruptive plumes emanating from Mount St. Helens. During 1980 and part of 1981, an infrared spectrometer was also used to measure carbon dioxide emission rates. At distances up to 25 km from Mount St. Helens, plume widths can range up to 20 km or more, with width/thickness ratios from 3 to about 30. Maximum sulfur dioxide concentrations in these plumes depend on wind speed and are typically under 5 ppm and usually 1 ppm or less. Close examination of the plume data reveals that the characteristics of quiescent plumes from Mount St. Helens are strongly affected by certain meteorological conditions such as thermal and wind stratification in the troposphere, as well as by the topography of the volcano. ?? 1992.

  3. Multipass reconfiguration of the HELEN Nd:glass laser at the Atomic Weapons Establishment.

    PubMed

    Norman, Michael J; Andrew, James E; Bett, Thomas H; Clifford, Roger K; England, John E; Hopps, Nicholas W; Parker, Kenneth W; Porter, Kenneth; Stevenson, Mark

    2002-06-20

    The HELEN high-power Nd:glass laser has been rebuilt in a new multipass configuration that requires fewer components to maintain existing performance. This is expected to lead to greater system availability and reduced running costs. We describe the new design, discuss some of the key issues that had to be addressed, and present operational results. PMID:12078672

  4. Meet Helen J. Post-Brown, Director: Sunbeam Child Care Center, Fairmont, West Virginia

    ERIC Educational Resources Information Center

    Exchange: The Early Childhood Leaders' Magazine Since 1978, 2005

    2005-01-01

    This article profiles Helen J. Post-Brown, director of Sunbeam Child Care Center in Fairmont and president of West Virginia Childcare Centers United, and explains how Post-Brown faced the obstacles when managing a child care business. In the fall of 1980, Post-Brown started Sunbeam as a small preschool with 12 children. Over the years, Sunbeam has…

  5. Large-N Nodal Seismic Deployment at Mount St Helens

    NASA Astrophysics Data System (ADS)

    Hansen, S. M.; Schmandt, B.; Vidale, J. E.; Creager, K. C.; Levander, A.; Kiser, E.; Barklage, M.; Hollis, D.

    2014-12-01

    In late July of 2014 over 900 autonomous short period seismometers were deployed within 12 km of the summit crater at Mount St Helens. In concert with the larger iMUSH experiment, these data constitute the largest seismic interrogation of an active volcano ever conducted. The array was deployed along the road and trail system of the national volcanic monument and adjacent regions with an average station spacing of 250 meters and included several station clusters with increased sampling density. The 10 Hz phones recorded the vertical component wavefield continuously at 250 Hz sampling rate over a period of approximately two weeks. During the recording time, the Pacific Northwest Seismic Network detected ~65 earthquakes within the array footprint ranging in magnitude from -0.9 to 1.1, the majority of which were located beneath the crater at less than 10 km depth. In addition to the natural seismicity, 23 explosion sources from the iMUSH active source experiment were recorded, several of which exceeded magnitude 2. Preliminary results for this project will include an expanded event catalog as the array should significantly reduce the detection threshold. The sheer number of instruments allows for stacking of station clusters producing high signal-to-noise beam traces which can be used for event triggering and for creating waveform templates to measure relative travel-times across the array via cross-correlation. The ability of the array to estimate focal mechanisms from event radiation patterns and delineate complex path effects will also be investigated. The density and azimuthal coverage provide by this array offers an excellent opportunity to investigate short-wavelength variations of the seismic wavefield in a complex geologic environment. Previous seismic tomography results suggest the presence of a shallow magma chamber at 1-3 km depth near the region of shallow seismicity as evidenced by a P wave low-velocity anomaly of at least -5.5% [Waite and Moran, 2009

  6. Blast dynamics at Mount St Helens on 18 May 1980

    USGS Publications Warehouse

    Kieffer, S.W.

    1981-01-01

    At 8.32 a.m. on 18 May 1980, failure of the upper part of the north slope of Mount St Helens triggered a lateral eruption ('the blast') that devastated the conifer forests in a sector covering ???500 km2 north of the volcano. I present here a steady flow model for the blast dynamics and propose that through much of the devastated area the blast was a supersonic flow of a complex multiphase (solid, liquid, vapour) mixture. The shape of the blast zone; pressure, temperature, velocity (Mach number) and density distributions within the flow; positions of weak and strong internal shocks; and mass flux, energy flux, and total energy are calculated. The shape of blast zone was determined by the initial areal expansion from the reservoir, by internal expansion and compression waves (including shocks), and by the density of the expanding mixture. The pressure within the flow dropped rapidly away from the source of the blast until, at a distance of ???11 km, the flow became underpressured relative to the surrounding atmosphere. Weak shocks within the flow subparallel to the east and west margins coalesced at about this distance into a strong Mach disk shock, across which the flow velocities would have dropped from supersonic to subsonic as the pressure rose back towards ambient. The positions of the shocks may be reflected in differences in the patterns of felled trees. At the limits of the devastated area, the temperature had dropped only 20% from the reservoir temperature because the entrained solids thermally buffered the flow (the dynamic and thermodynamic effects of the admixture of the surrounding atmosphere and the uprooted forest and soils into the flow are not considered). The density of the flow decreased with distance until, at the limits of the blast zone, 20-25 km from the volcano, the density became comparable with that of the surrounding (dirty) atmosphere and the flow became buoyant and ramped up into the atmosphere. According to the model, the mass flux per

  7. Clast comminution during pyroclastic density current transport: Mt St Helens

    NASA Astrophysics Data System (ADS)

    Dawson, B.; Brand, B. D.; Dufek, J.

    2011-12-01

    Volcanic clasts within pyroclastic density currents (PDCs) tend to be more rounded than those in fall deposits. This rounding reflects degrees of comminution during transport, which produces an increase in fine-grained ash with distance from source (Manga, M., Patel, A., Dufek., J. 2011. Bull Volcanol 73: 321-333). The amount of ash produced due to comminution can potentially affect runout distance, deposit sorting, the volume of ash lofted into the upper atmosphere, and increase internal pore pressure (e.g., Wohletz, K., Sheridan, M. F., Brown, W.K. 1989. J Geophy Res, 94, 15703-15721). For example, increased pore pressure has been shown to produce longer runout distances than non-comminuted PDC flows (e.g., Dufek, J., and M. Manga, 2008. J. Geophy Res, 113). We build on the work of Manga et al., (2011) by completing a pumice abrasion study for two well-exposed flow units from the May 18th, 1980 eruption of Mt St Helens (MSH). To quantify differences in comminution from source, sampling and the image analysis technique developed in Manga et al., 2010 was completed at distances proximal, medial, and distal from source. Within the units observed, data was taken from the base, middle, and pumice lobes within the outcrops. Our study is unique in that in addition to quantifying the degree of pumice rounding with distance from source, we also determine the possible range of ash sizes produced during comminution by analyzing bubble wall thickness of the pumice through petrographic and SEM analysis. The proportion of this ash size is then measured relative to the grain size of larger ash with distance from source. This allows us to correlate ash production with degree of rounding with distance from source, and determine the fraction of the fine ash produced due to comminution versus vent-fragmentation mechanisms. In addition we test the error in 2D analysis by completing a 3D image analysis of selected pumice samples using a Camsizer. We find that the roundness of PDC

  8. Lateral blasts at Mount St. Helens and hazard zonation

    USGS Publications Warehouse

    Crandell, D.R.; Hoblitt, R.P.

    1986-01-01

    Lateral blasts at andesitic and dacitic volcanoes can produce a variety of direct hazards, including ballistic projectiles which can be thrown to distances of at least 10 km and pyroclastic density flows which can travel at high speed to distances of more than 30 km. Indirect effect that may accompany such explosions include wind-borne ash, pyroclastic flows formed by the remobilization of rock debris thrown onto sloping ground, and lahars. Two lateral blasts occurred at a lava dome on the north flank of Mount St. Helens about 1200 years ago; the more energetic of these threw rock debris northeastward across a sector of about 30?? to a distance of at least 10 km. The ballistic debris fell onto an area estimated to be 50 km2, and wind-transported ash and lapilli derived from the lateral-blast cloud fell on an additional lobate area of at least 200 km2. In contrast, the vastly larger lateral blast of May 18, 1980, created a devastating pyroclastic density flow that covered a sector of as much as 180??, reached a maximum distance of 28 km, and within a few minutes directly affected an area of about 550 km2. The May 18 lateral blast resulted from the sudden, landslide-induced depressurization of a dacite cryptodome and the hydrothermal system that surrounded it within the volcano. We propose that lateral-blast hazard assessments for lava domes include an adjoining hazard zone with a radius of at least 10 km. Although a lateral blast can occur on any side of a dome, the sector directly affected by any one blast probably will be less than 180??. Nevertheless, a circular hazard zone centered on the dome is suggested because of the difficulty of predicting the direction of a lateral blast. For the purpose of long-term land-use planning, a hazard assessment for lateral blasts caused by explosions of magma bodies or pressurized hydrothermal systems within a symmetrical volcano could designate a circular potential hazard area with a radius of 35 km centered on the volcano

  9. Double-Difference Earthquake Locations Using imaging Magma Under St. Helens (iMUSH) Data

    NASA Astrophysics Data System (ADS)

    Williams, M. C. B.; Ulberg, C. W.; Creager, K. C.

    2015-12-01

    The imaging Magma Under St. Helens (iMUSH) project deployed a magnetotelluric survey, high-resolution active-source experiment, two-year passive-source experiment, and gathered geochemical-petrological data to better understand the magmatic architecture of Mount St. Helens. A primary goal of the passive source experiment is to create 3-D P-wave and S-wave velocity models under the volcano from the surface to the slab. We use hypoDD, a double-difference algorithm, to gain high-precision relative earthquake locations for several hundred events within tens of kilometers of the Mount St. Helens crater. We use data from the first half (2014 June- 2015 July) of the two-year passive-source component of the iMUSH array recording six hundred useable earthquakes with a high-event density near the volcanic crater. The array includes seventy evenly-spaced broadband seismometers continuously sampling at 50 Hz within a 50 km radius of Mount St. Helens, and is augmented by dozens of permanent network stations. Precise relative earthquake locations are determined for spatially clustered hypocenters using a combination of hand picked P-wave arrivals and high-precision relative times determined by cross correlation of waveforms recorded at a common station for event pairs using a 1-D velocity structure. These high-quality relative times will be used to help constrain seismic tomography models as well. We will interrupt earthquake clusters in the context of emerging 3-D wave-speed models from the active-source and passive-source observations. We are examining the relationship between hypocentral locations and regions of partial melt, as well as the relationship between hypocentral locations and the NNW-SSE trending Saint Helens seismic Zone.

  10. A Gentle Frost: Poet Helen Frost Talks about the Healing Power of Poetry and Her Latest Novel

    ERIC Educational Resources Information Center

    Margolis, Rick

    2006-01-01

    This article presents an interview with poet Helen Frost. Frost talked about how poetry can help at-risk children. She also related the challenges she faced when she wrote her latest book titled "The Braid."

  11. Cataclastic production of volcanic ash at Mount Saint Helens

    NASA Astrophysics Data System (ADS)

    Kennedy, Lori A.; Russell, James K.

    2012-01-01

    The 2004-2008 eruption of Mt. St. Helens (MSH) produced a series of lava domes and spines distinguished by the occurrence of an enveloping carapace of finely comminuted, weakly indurated fault gouge. The fault gouge results from fracture and shear strain, causing comminution of dacite along the conduit walls during ascent. The faulting associated with the formation of gouge is assumed to be the origin of a repetitive microseismicity (i.e., “drumbeat” seismicity) sourced at ∼0.5-1 km depth. The early phases of dome extrusion were attended by several small explosive events producing plumes of volcanic ash derived largely from the fault gouge. Here we present experimental results that establish the requisite conditions for this cataclastic production of volcanic ash at MSH. The experiments are low temperature rock deformation experiments performed on MSH dacite under confining pressures consistent with conduit pressures (0.1, 25, 50, 75 MPa). The first set of experiments ended once a through-going shear fracture was formed; these produced a highly localized fault surface and associated fault gouge. A second set of experiments allowed frictional sliding along the fault surface after failure thereby exploring the role of shear strain on grain size reduction of the gouge. Rock strength increases with confining pressure (from 139 to 722 MPa at 0.1 to 75 MPa). Unconfined loading of the MSH dacite produced several longitudinal fractures with little gouge and a small stress drop (∼120 MPa), whereas 75 MPa experiments produced a near-linear shear fracture, with a stress drop of ∼300 MPa. The amount of gouge and the grain size distribution of the gouge are only weakly affected by the confining pressure. Continued sliding (i.e., shear strain) causes a substantial increase in the amount of gouge but does not increase the number abundance of the finest (<10 μm) particles. Thus, the finest particles are an expression only of the magnitude of the stress drop event

  12. Cataclastic Production of Volcanic Ash at Mount Saint Helens

    NASA Astrophysics Data System (ADS)

    Kennedy, L.; Russell, K.; CentreExperimental Studies of the Lithosphere

    2011-12-01

    The 2004-2008 eruption of Mt. St. Helens (MSH) produced a series of lava domes and spines distinguished by the occurrence of an enveloping carapace of finely comminuted, weakly indurated fault gouge. The fault gouge results from fracture and shear strain, causing comminution of dacite along the conduit walls during ascent. The faulting associated with the formation of gouge is assumed to be the origin of a repetitive microseismicity (i.e., "drumbeat" seismicity) sourced at ~ 0.5 - 1 km depth. The early phases of dome extrusion were attended by several small explosive events producing plumes of volcanic ash derived largely from the fault gouge. Here we present experimental results that establish the requisite conditions for this cataclastic production of volcanic ash at MSH. The experiments are low temperature rock deformation experiments performed on MSH dacite under confining pressures consistent with conduit pressures (0.1, 25, 50, 75 MPa). The first set of experiments ended once a through-going shear fracture was formed; these produced a highly localized fault surface and associated fault gouge. A second set of experiments allowed frictional sliding along the fault surface after failure thereby exploring the role of shear strain on grain size reduction of the gouge. Rock strength increases with confining pressure (from 139-722 MPa at 0.1 to 75 MPa). Unconfined loading of the MSH dacite produced several longitudinal fractures with little gouge and a small stress drop (~120 MPa), whereas 75 MPa experiments produced a near-linear shear fracture, with a stress drop of ~300 MPa. The amount of gouge and the grain size distribution of the gouge are only weakly affected by the confining pressure. Continued sliding (i.e., shear strain) causes a substantial increase in the amount of gouge but does not increase the number abundance of the finest (<10 mm) particles. Thus, the finest particles are an expression only of the magnitude of the stress drop event (fracture) and

  13. Mount St. Helens Lava Domes, Then and Now

    NASA Astrophysics Data System (ADS)

    Fink, J.; Anderson, S. W.

    2004-12-01

    When the Mount St. Helens (MSH) lava dome grew from 1980-1986, little was known about how volatiles, vesicularity or crystallinity were distributed in domes, or about overall patterns of growth. Six years of MSH observations, coupled with comparative petrologic, structural, and analog laboratory studies of domes at Soufriere of St. Vincent, Augustine, Redoubt, Merapi, Montserrat, Santiaguito, and elsewhere have provided a much better foundation for evaluating the 2004 eruptive activity. One of the main goals of the earlier studies was to differentiate intrusive processes from those operating when magma ascends near and onto the volcano's surface. Here we use some of our earlier isotopic, petrographic and remote sensing observations of textures and volatiles to speculate about the processes operating in 2004. We earlier linked variations in lava textures to degassing processes operating during ascent and emplacement. MSH lava was extruded in a relatively dense state. When the water content was high enough, hot, ductile lava beneath the quenched outer rind of the dome vesiculated during surface flow, creating a 1 to 2 meter thick scoriaceous carapace. Post-1983 lavas lacked this scoria because the dome had reached a critical size and strength, resulting in lower short-term eruption rates and extensive degassing of lava en route to the surface. Observations of a dense "fin" in October 2004 suggest that this initial dome-building magma experienced thorough degassing as it broke a new path to the crater floor. We also used hydrogen isotope analyses of water in 1980-86 dome samples to infer degassing processes occurring in the source magma chamber and conduit system. Water content and hydrogen isotopic values of dome samples varied according to texture, position on the flow, and repose period prior to eruption. We saw two trends: (1) lava from lobes emplaced after longer repose intervals were deuterium-enriched, and (2) within individual lobes, relatively dry, smooth

  14. Inclusions in Mount St. Helens dacite erupted from 1980 through 1983

    NASA Astrophysics Data System (ADS)

    Heliker, Christina

    1995-07-01

    Inclusions of plutonic, metavolcanic and volcanic rocks are abundant in dacite pumice and lava from the 1980-1986 eruption sequence at Mount St. Helens. Point counts of inclusions exposed in talus blocks from the dome from 1980 through 1983 show that inclusions form approximately 3.5 vol% of the lava. Eighty-five percent of the inclusions are medium-grained gabbros with an average diameter of 6 cm. Additional rock types include quartz diorite, hornfelsic basalt, dacite, andesite and vein quartz. Disaggregated inclusions are common and define shear planes within the dome. These fragmented inclusions may significantly contaminate analyses of the dacite. The gabbroic inclusions are of four distinct types, all with mineral assemblages consistent with crystallization pressures of less than 9 kb. Textures and major-element compositions indicate that most of the gabbroic inclusions are cumulates. The most abundant inclusion type is laminated gabbronorite, which contains up to 9% interstitial glass, derived from partial melting. The presence of quartz veins and hornblende-bearing veins within sheared zones in the laminated gabbronorite indicates that the source of these inclusions was holocrystalline rock that had been penetrated by water-rich fluids. The gabbronorite contained sufficient water to be susceptible to partial melting when the magma that fed the 1980-1986 eruption sequence was emplaced nearby. Various types of gabbroic inclusions, including the laminated gabbronorite, are common in Mount St. Helens lavas of approximately the last 3000 years. This coincides with the interval in which Mount St. Helens first erupted basalt and basaltic andesite lavas. These observations, together with the fact that the gabbroic inclusions are compositionally unlike any of the Tertiary intrusive rocks in the Mount St. Helens area, strongly suggest that the inclusions are related to the introduction of basalt to the Mount St. Helens magmatic system. The source of the gabbros could

  15. Twins Across the Pacific: A Comparison of Bezymianny Volcano, Russia and Mount St. Helens, USA

    NASA Astrophysics Data System (ADS)

    Thelen, W.

    2006-12-01

    Triggered sector collapse is a common event in the lifetime of a stratovolcano. Classic triggered edifice failures were observed in historic time both at Bezymianny Volcano, Russia and at Mount St. Helens, Washington providing an ideal opportunity for comparison. The volcanic behaviors associated with these eruptions and subsequent dome growth share many striking similarities, including morphology of the dome, despite compositional variations. Bezymianny volcano experienced a sector collapse and associated lateral blast on March 30, 1956. Immediately following, voluminous dome extrusion commenced, punctuated by minor explosive eruptions. Dome growth originated with the extrusion of intact blocks of andesite, forming a structure called the "Nautilus". Beginning in 1977, strong explosive eruptions were occasionally accompanied by lava flows near the top of the dome. Recently, dome growth has been accompanied by powerful plinian and sub-plinian eruptions occurring nearly bi-annually, the most recent having occurred on May 9, 2006. Compositions have become increasingly more mafic over time. A lateral blast and plinian eruption occurred at Mount St. Helens on May 18, 1980, approximately equivalent in landslide and tephra volume to the 1956 eruption of Bezymianny. Like Bezymianny, Mount St. Helens began dome extrusion coupled with minor eruptive activity immediately after the decompression event, but on a smaller volume scale. In addition, the dome at Mount St. Helens exhibited features called "Whalebacks" beginning in 2004, similar to the "Nautilus" seen at Bezymianny. Unlike Bezymianny, the dacitic composition of erupted materials has remained nearly constant or grown slightly more silicic with time and, as of August 2006, Mount St. Helens has not exhibited plinian or sub-plinian eruptions since 1980. Both volcanoes currently exhibit only very shallow seismicity, despite evidence that the magma is coming from much deeper sources. During the summer of 2006, two

  16. The 19 March 1982 Eruption and Lahar at Mount Saint Helens: Implications for Martian Outlfow Channels?

    NASA Technical Reports Server (NTRS)

    Beach, G. L.

    1984-01-01

    A small explosive eruption of Mount St. Helens set into motion an unusually complex series of geomorphic and hydrologic processes that had not previously been described in the literature. This event was unusual in that a laterally-directed eruption dislodged and mobilized a thick snowpack from the surrounding crater floor and walls, resulting in the formation of a temporary lake. Catastrophic release of this self-impounded lake spawned a series of destructive debris avalanches and debris flows that moved rapidly down the volcano's north flank and into the North Toutle River valley. Catastrophic release of volatiles mobilized by volcanic activity has been discussed as a possible mechanism to explain a class of outflow channels on Mars. The eruption of Mount St. Helens provides a unique opportunity to study the deposits and landforms created by such an event; a more detailed field study and examination of Viking photographs of martian outflow channels is underway.

  17. Radio interferometric detection of a traveling ionospheric disturbance excited by the explosion of Mount St. Helens

    NASA Technical Reports Server (NTRS)

    Roberts, D. H.; Rogers, A. E. E.; Allen, B. R.; Bennett, C. L.; Burke, B. F.; Greenfield, P. E.; Lawrence, C. R.; Clark, T. A.

    1982-01-01

    A large-amplitude traveling ionospheric disturbance (TID) was detected over Owens Valley, California, on May 18, 1980, by a highly sensitive very long baseline interferometry (VLBI) radio astronomy experiment. This TID is interpreted as the response of the ionosphere to a gravity wave excited in the neutral atmosphere by the explosion of Mount St. Helens that took place at 1532 UT on that day. A model, invoking the point-excitation of internal gravity waves in an isothermal atmosphere, which fits observations of the TID at several other stations, leads to identification of the features observed in the VLBI data. Small-amplitude higher-frequency changes in the ionosphere were detected for several hours after the passage of the large-amplitude Mount St. Helens TID, but it is not clear whether these were excited by the passage of the gravity wave or were background fluctuations.

  18. Processing and interpretation of microbarograph signals generated by the explosion of Mount St. Helens

    SciTech Connect

    Delclos, C.; Blanc, E. ); Broche, P. ); Glangeaud, F.; Lacoume, J.L. )

    1990-04-20

    Following the eruption of the Mount St. Helens volcano on May 18, 1980, atmospheric waves were recorded by a network of micrographs located over 7,000 km from the source. Analysis of these data requires the use of complex processing techniques based on a high-resolution method to extract the signals produced by the St. Helens source from spurious waves or noise in each record. This facilitates interpretation of the wave trains in terms of propagation modes. It is thus shown that Lamb mode L{sub 0} is present in the low-frequency part of all signals, whereas acoustic modes (more probably A{prime}{sub 2}) are needed to explain all the properties of the high-frequency part, which is clearly observed for a westward and a southward propagation.

  19. Radio interferometric detection of a traveling ionospheric disturbance excited by the explosion of Mount St. Helens

    NASA Astrophysics Data System (ADS)

    Roberts, D. H.; Rogers, A. E. E.; Allen, B. R.; Bennett, C. L.; Burke, B. F.; Greenfield, P. E.; Lawrence, C. R.; Clark, T. A.

    1982-08-01

    A large-amplitude traveling ionospheric disturbance (TID) was detected over Owens Valley, California, on May 18, 1980, by a highly sensitive very long baseline interferometry (VLBI) radio astronomy experiment. This TID is interpreted as the response of the ionosphere to a gravity wave excited in the neutral atmosphere by the explosion of Mount St. Helens that took place at 1532 UT on that day. A model, invoking the point-excitation of internal gravity waves in an isothermal atmosphere, which fits observations of the TID at several other stations, leads to identification of the features observed in the VLBI data. Small-amplitude higher-frequency changes in the ionosphere were detected for several hours after the passage of the large-amplitude Mount St. Helens TID, but it is not clear whether these were excited by the passage of the gravity wave or were background fluctuations.

  20. Airborne aerosol measurements in the quiescent plume of Mount Saint Helens September, 1980

    NASA Technical Reports Server (NTRS)

    Phelan, J. M.; Finnegan, D. L.; Ballantine, D. S.; Zoller, W. H.; Hart, M. A.; Moyers, J. L.

    1982-01-01

    A study of the emissions from the Mt. St. Helens volcano was conducted to obtain data for an assessment of the importance of volcanoes as a global source of volatile trace elements to the atmosphere and to the global biochemical cycles of these elements. Sampling was done on board an Orion P-3 turboprop aircraft modified for tropospheric aerosol and gas sampling. Two filter collection systems were used. Samples were collected on a single flight on September 22, 1980, at which time the volcano was emitting a stable plume to an altitude of between 2 and 3 km. The results regarding the concentrations of aerosols obtained for this mission are presented in a table. Attention is also given to data concerning particulate vs. gas phase sulfur in the Mt. Saint Helens plume, and the estimated volcanic particle flux of selected volatile elements.

  1. Monitoring vegetation recovery patterns on Mount St. Helens using thermal infrared multispectral data

    NASA Technical Reports Server (NTRS)

    Langran, Kenneth J.

    1986-01-01

    The Mount St. Helens 1980 eruption offers an opportunity to study vegetation recovery rates and patterns in a perturbed ecosystem. The eruptions of Mount St. Helens created new surfaces by stripping and implacing large volumes of eroded material and depositing tephra in the blast area and on the flanks of the mountain. Areas of major disturbance are those in the blast zone that were subject to debris avalanche, pyroclastic flows, mudflows, and blowdown and scorched timber; and those outside the blast zone that received extensive tephra deposits. It was observed that during maximum daytime solar heating, surface temperatures of vegetated areas are cooler than surrounding nonvegetated areas, and that surface temperature varies with percent vegetation cover. A method of measuring the relationship between effective radiant temperature (ERT) and percent vegetation cover in the thermal infrared (8 to 12 microns) region of the electromagnetic spectrum was investigated.

  2. Atmospheric Effects and Potential Climatic Impact of the 1980 Eruptions of Mount St. Helens

    SciTech Connect

    Deepak, A.

    1982-10-01

    Measurements and studies of the 1980 Mount St. Helens volcanic eruptions and their atmospheric effects and climatic impact are addressed. Specific areas discussed include: (1) nature and impact of volcanic eruptions, (2) in situ measurements of effluents, (3) remote sensing measurements, (4) transport and dispersion of volcanic effluents, (5) chemistry of volcanic effluents, and (6) weather and potential climate impact. For individual titles, see N83-11535 through N83-11562.

  3. Size distributions and mineralogy of ash particles in the stratosphere from eruptions of Mount St. Helens

    NASA Technical Reports Server (NTRS)

    Farlow, N. H.; Oberbeck, V. R.; Snetsinger, K. G.; Ferry, G. V.; Polkowski, G.; Hayes, D. M.

    1981-01-01

    Samples from the stratosphere obtained by U-2 aircraft after the first three major eruptions of Mount St. Helens contained large globules of liquid acid and ash. Because of their large size, these globules had disappeared from the lower stratosphere by late June 1980, leaving behind only smaller acid droplets. Particle size distributions and mineralogy of the stratospheric ash grains demonstrate inhomogeneity in the eruption clouds.

  4. Filter measurements of stratospheric sulfate and chloride in the eruption plume of Mount St. Helens

    SciTech Connect

    Gandrud, B.W.; Lazrus, A.L.

    1981-01-01

    Five flights of the U-2 aircraft with a filter sampler aboard were flown in the Mount St. Helens debris from 19 May to 17 June 1980. Sulfate concentrations as large as 216 times the expected background were observed. The enhancements of acid chloride vapor were considerably smaller, suggesting an insignificant increase of background values of hydrogen chloride once the plume is well mixed throughout the lower stratosphere.

  5. Carbonyl sulfide and carbon disulfide from the eruptions of Mount St. Helens

    SciTech Connect

    Rasmussen, R.A.; Khalil, M.A.K.; Dalluge, R.W.; Penkett, S.A.; Jones, B.

    1982-01-01

    Ash from the massive 18 May 1980 eruption of Mount St. Helens readily gave off large amounts of carbonyl sulfide and carbon disulfide gases at room temperature. These findings suggest that the sulfur that enhances the Junge sulfate layer in the stratosphere after volcanic eruptions could be carried directly to the upper atmosphere as carbonyl sulfide and carbon disulfide adsorbed on ash particles from major volcanic eruptions.

  6. Trace element composition of the Mount St. Helens plume - Stratospheric samples from the 18 May eruption

    NASA Technical Reports Server (NTRS)

    Vossler, T.; Anderson, D. L.; Aras, N. K.; Phelan, J. M.; Zoller, W. H.

    1981-01-01

    Atmospheric particulate material collected from the stratosphere in the plume of the 18 May 1980 eruption of the Mount St. Helens volcano was quite similar in composition to that of ash that fell to the ground in western Washington. However, there were small but significant differences in concentrations of some elements with altitude, indicating that the stratospheric material was primarily produced from fresh magma, not fragments of the mountain.

  7. Eruption-triggered avalanche, flood, and lahar at mount st. Helens--effects of winter snowpack.

    PubMed

    Waitt, R B; Pierson, T C; Macleod, N S; Janda, R J; Voight, B; Holcomb, R T

    1983-09-30

    An explosive eruption of Mount St. Helens on 19 March 1982 had substantial impact beyond the vent because hot eruption products interacted with a thick snowpack. A blast of hot pumice, dome rocks, and gas dislodged crater-wall snow that avalanched through the crater and down the north flank. Snow in the crater swiftly melted to form a transient lake, from which a destructive flood and lahar swept down the north flank and the North Fork Toutle River. PMID:17759014

  8. A gravity current model for the May 18, 1980 Mount St. Helens plume

    NASA Technical Reports Server (NTRS)

    Bursik, M. I.; Carey, S. N.; Sparks, R. S. J.

    1992-01-01

    Observations of the stratospheric plume from the May 18, 1980 Mount St. Helens eruption suggest that it spread in the crosswind direction as an intrusive gravity current, as it was transported downwind. Grain size analyses of the plinian tephra are consistent with this model, suggesting that to distances of many hundreds of kilometers, turbulent atmospheric diffusion played a secondary role in plume spreading and tephra dispersal.

  9. Absorption of visible radiation by aerosols in the volcanic plume of Mount St. Helens

    NASA Technical Reports Server (NTRS)

    Ogren, J. A.; Charlson, R. J.; Radke, L. F.; Domonkos, S. K.

    1981-01-01

    Samples of particles from Mount St. Helens were collected in both the stratosphere and troposphere for measurement of the light absorption coefficient. Results indicate that the stratospheric dust had a small but finite absorption coefficient ranging up to 2 x 10 to the minus 7 per meter at a wavelength of 0.55 micron, which is estimated to yield an albedo for single scatter of 0.98 or greater. Tropospheric results showed similar high values of an albedo for single scatter

  10. Measurements of cloud condensation nuclei in the stratosphere around the plume of Mount St. Helens

    SciTech Connect

    Rogers, C.F.; Hudson, J.G.; Kocmond, W.C.

    1981-01-01

    Measurements of cloud condensation nuclei were made from small samples of stratospheric air taken from a U-2 aircraft at altitudes ranging from 13 to 19 kilometers. The measured concentrations of nuclei both in and outside the plume from the May and June 1980 eruptions of Mount St. Helens were higher than expected, ranging from about 100 to about 1000 per cubic centimeter active at 1 percent supersaturation.

  11. Histopathological reaction of the lung to Mount St. Helens volcanic ash

    SciTech Connect

    Sanders, C.L.

    1987-06-01

    The pulmonary toxicity of respirable particle size (count median diameter, 0.5 to 1.6 ..mu..m) Mount St. Helens volcanic ash was studied. Total particulate doses of 22 to 77 mg suspended in sterile 0.9% sodium chloride solution were given in 1 to 7 consecutive weekly intratracheal instillations. The lungs and mediastinal lymph nodes were histologically examined at intervals up to 400 days after instillation.

  12. Impact of Mount St. Helens eruption on hydrology and water quality

    SciTech Connect

    Bonelli, J.E.; Taylor, H.E.; Klein, J.M.

    1982-10-01

    The 1980 eruptions of Mount St. Helens in southeast Washington resulted in a pronounced effect on the surface and ground water resources of the state. In response to the volcanic activity, the U.S. Geological Survey intensified statewide surface and ground water sampling programs to determine the nature and magnitude of the volcanic-induced variations. Streams to the east of Mount St. Helens received the major ash fallout. Chemical effects were best noted in smaller streams sampled 60 to 70 miles northeast of Mount St. Helens. The chemical variations observed were pronounced but short lived. Sulfate and chloride increases in anionic composition were prevalent immediately following the eruption however, the original bicarbonate predominance was again attained within several days. Suspended iron and aluminum concentrations were similarly elevated during the period of greatest ash deposition (highest turbidity) however, the dissolved concentrations remained relatively constant. Depressions of pH were minor and short lived. Streams draining to the south, tributaries to the Columbia river, showed little observable changes in water chemistry. Streams draining to the west (Toutle river and its tributaries) were compositionally affected by the various volcanic activities. Chloride and sulfate anion percentage exceeded the bicarbonate percentage up to one month following the eruption period. Streams and lakes sampled in the immediate vicinity of Mount St. Helens, in addition to trace metals, contained organic compounds derived from decomposing wood buried in the debris deposits. This organic material may constitute a significant source of organic compounds to surface and ground water for some time to come.

  13. Absorption of visible radiation by aerosols in the volcanic plume of Mount St. Helens

    SciTech Connect

    Ogren, J.A.; Charlson, R.J.; Radke, L.F.; Domonkos, S.K.

    1981-01-01

    Samples of particles from Mount St. Helens were collected in both the stratosphere and troposhere for measurement of the light absorption coefficient. Results indicate that the stratospheric dust had a small but finite absorption coefficient ranging up to 2 x 10-7 per meter at a wavelength of 0.55 micrometer, which is estimated to yield an albedo for single scatter of 0.98 or greater. Tropospheric results showed similar high values of an albedo for single scatter.

  14. Initial effects of ashfall from mount st. Helens on vegetation in eastern washington and adjacent idaho.

    PubMed

    Mack, R N

    1981-07-31

    Extensive plant damage from the 18 May 1980 eruption of Mount St. Helens was largely restricted to acaulescent andprostrate dicot species in the ashfall area east of the Cascade Range (more than 150 kilometersfrom the vent). Veratrum californicum, a large monocot, displayed widespread stem death through mechanical overloading of the plant's clasping leaves. The ash surface in this area presents new opportunities for both seeds and seed predators. PMID:17794839

  15. Mercury content of equisetum plants around mount st. Helens one year after the major eruption.

    PubMed

    Siegel, B Z; Siegel, S M

    1982-04-16

    The mercury content of young Equisetum plants collected around Mount St. Helens was higher in the direction of Yakima and Toppenish, Washington (northeast to east-northeast), than at any other compass heading and was about 20 times that measured around Portland, Oregon. The increase in substratum mercury was not as pronounced as that in plants but was also higher toward the northeast, the direction taken by the May 1980 volcanic plume. PMID:17832743

  16. Mount St. Helens, Washington, 1980 volcanic eruption: magmatic gas component during the first 16 days

    SciTech Connect

    Stoiber, R.E.; Williams, S.N.; Malinconico, L.L.

    1980-01-01

    Eruption plumes of Mount St. Helens, Washington, showed low rates of sulfur dioxide emission, and ash leachates had low ratios of sulfur to chlorine. These data and the nonvesicularity of ash fragments are indicative of only a small eruptive magmatic component. The low amounts of soluble fluorine on the ashes pose no health problems. Violent magmatic activity is possible, and thus continued geochemical monitoring is advised.

  17. Trace element composition of the Mount St. Helens plume: stratospheric samples from the 18 May eruption

    SciTech Connect

    Vossler, T.; Anderson, D.L.; Aras, N.K.; Phelan, J.M.; Zoller, W.H.

    1981-01-01

    Atmospheric particulate material collected from the stratosphere in plume of the 18 May 1980 eruption of the Mount St. Helens volcano was quite similar in composition to that of ash that fell to the ground in western Washington. However, there were small but significant differences in concentrations of some elements with altitude, indicating that the statospheric material was primarily produced from fresh magma, but fragments of the mountain.

  18. Temporal change in coda wave attenuation observed during an eruption of Mount St. Helens

    SciTech Connect

    Fehler, M.; Roberts, P.; Fairbanks, T.

    1988-05-10

    During the past few years there have been numerous reports of changes in coda wave attenuation occurring before major earthquakes. These observations are important because they may provide insight into stress-related structural changes taking place in the focal region prior to the occurrence of large earthquakes. The results of these studies led us to suspect that temporal changes in coda wave attenuation might also accompany volcanic eruptions. By measuring power decay envelopes for earthquakes at Mount St. Helens recorded before, during, and after an eruption that took place during September 3--6, 1981, we found that coda Q/sup -1/ for frequencies between 6 and 30 Hz was 20--30% higher before the eruption than after. The change is attributed to an increase in the density of open microcracks in the rock associated with inflation of the volcano prior to the eruption. Q/sup -1/ was found to be only weakly dependent on frequency and displayed a slight peak near 10 Hz. The weak frequency dependence is attributed to the dominance of intrinsic attenuation over scattering attenuation, since it is generally accepted that intrinsic attenuation is constant with frequency, whereas scattering attenuation decreases strongly at higher frequencies. The weak frequency dependence of Q/sup -1/ at Mount St. Helens contrasts with results reported for studies in nonvolcanic regions. The peak in Q/sup -1/ near 10 Hz at Mount St. Helens is attributed to the scale length of heterogeneity responsible for generating backscattered waves. Results for nonvolcanic regions have shown this peak to occur near 0.5 Hz. Thus a smaller scale length of heterogeneity is required to explain the 10-Hz peak at Mount St. Helens. copyright American Geophysical Union 1988

  19. Carbonyl sulfide and carbon disulfide from the eruptions of mount st. Helens.

    PubMed

    Rasmussen, R A; Khalil, M A; Dalluge, R W; Penkett, S A; Jones, B

    1982-02-01

    Ash from the massive 18 May 1980 eruption of Mount St. Helens readily gave off large amounts of carbonyl sulfide and carbon disulfide gases at room temperature. These findings suggest that the sulfur that enhances the Junge sulfate layer in the stratosphere after volcanic eruptions could be carried directly to the upper atmosphere as carbonyl sulfide and carbon disulfide adsorbed on ash particles from major volcanic eruptions. PMID:17842402

  20. Size distributions and mineralogy of ash particles in the stratosphere from eruptions of Mount St. Helens

    SciTech Connect

    Farlow, N.H.; Oberbeck, V.R.; Snetsinger, K.G.; Ferry, G.V.; Polkowski, G.; Hayes, D.M.

    1981-01-01

    Samples from the stratosphere obtained by U-2 aircraft after the first three major eruptions of Mount St. Helens contained large globules of liquid acid and ash. Because of their large size, these globules had disappeared from the lower stratosphere by late June 1980, leaving behind only smaller acid droplets. Particle-size distributions and mineralogy of the stratospheric ash grains demonstrate inhomogeneity in the eruption clouds.

  1. Pre-1980 tephra-fall deposits erupted from Mount St. Helens, Washington

    USGS Publications Warehouse

    Mullineaux, Donal R.

    1996-01-01

    More than 100 tephra-fall deposits erupted from Mount St. Helens within about the last 40,000 years are grouped into tephra sets and layers distinguished from each other chiefly by differences in mineral composition and age. The tephra deposits record a complex history of the volcano, form important time-stratigraphic markers, and provide information about probable kinds, frequencies, and magnitudes of future eruptions.

  2. Impact of Mount St. Helens eruption on hydrology and water quality

    NASA Technical Reports Server (NTRS)

    Bonelli, J. E.; Taylor, H. E.; Klein, J. M.

    1982-01-01

    The 1980 eruptions of Mount St. Helens in southeast Washington resulted in a pronounced effect on the surface and ground water resources of the state. In response to the volcanic activity, the U.S. Geological Survey intensified statewide surface and ground water sampling programs to determine the nature and magnitude of the volcanic-induced variations. Streams to the east of Mount St. Helens received the major ash fallout. Chemical effects were best noted in smaller streams sampled 60 to 70 miles northeast of Mount St. Helens. The chemical variations observed were pronounced but short lived. Sulfate and chloride increases in anionic composition were prevalent immediately following the eruption; however, the original bicarbonate predominance was again attained within several days. Suspended iron and aluminum concentrations were similarly elevated during the period of greatest ash deposition (highest turbidity); however, the dissolved concentrations remained relatively constant. Depressions of pH were minor and short lived. Streams draining to the south, tributaries to the Columbia river, showed little observable changes in water chemistry. Streams draining to the west (Toutle river and its tributaries) were compositionally affected by the various volcanic activities. Chloride and sulfate anion percentage exceeded the bicarbonate percentage up to one month following the eruption period. Streams and lakes sampled in the immediate vicinity of Mount St. Helens, in addition to trace metals, contained organic compounds derived from decomposing wood buried in the debris deposits. This organic material may constitute a significant source of organic compounds to surface and ground water for some time to come.

  3. Absorption of visible radiation by aerosols in the volcanic plume of mount st. Helens.

    PubMed

    Ogren, J A; Charlson, R J; Radke, L F; Domonkos, S K

    1981-02-20

    Samples of particles from Mount St. Helens were collected in both the stratosphere and troposphere for measurement of the light absorption coefficient. Results indicate that the stratospheric dust had a small but finite absorption coefficient ranging up to 2 x 10(-7) per meter at a wavelength of 0.55 micrometer, which is estimated to yield an albedo for single scatter of 0.98 or greater. Tropospheric results showed similar high values of an albedo for single scatter. PMID:17740397

  4. Preliminary Shear Velocity Tomography of Mt St Helens, Washington from iMUSH Array

    NASA Astrophysics Data System (ADS)

    Crosbie, K.; Abers, G. A.; Creager, K. C.; Moran, S. C.; Denlinger, R. P.; Ulberg, C. W.

    2015-12-01

    The imaging Magma Under Mount St Helens (iMUSH) experiment will illuminate the crust beneath Mt St Helens volcano. The ambient noise tomography (ANT) component of this experiment measures shear velocity structure, which is more sensitive than P velocity to the presence of melt and other pore fluids. Seventy passive-source broadband seismometers for iMUSH were deployed in the summer of 2014 in a dense array of 100 Km diameter with a 10 km station spacing. We cross correlated ambient noise in 120 s windows and summed the result over many months for pairs of stations. Then frequency-domain methods on these cross correlations are employed to measure the phase velocities (Ekström et al. Geophys Rev Lett, 2009). Unlike velocities attained by group velocity methods, velocities for path lengths as small as one wavelength can be measured, enabling analysis of higher frequency signals and increasing spatial resolution. The minimum station spacing from which signals can be recovered ranges from 12 km at 0.18 Hz, a frequency that dominantly samples the upper crust to 20 km, to 37 km at 0.04 Hz, a frequency sensitive to structure through the crust and uppermost mantle, with lower spacing at higher frequencies. These phase velocities are tomographically inverted to obtain shear velocity maps for each frequency, assuming ray theory. Initial shear velocity maps for frequencies between 0.04-0.18 Hz reveal low-velocity sediments in the Puget Lowland west of Mount St Helens at 0.16-0.18 Hz, and a low velocity zone near 0.10 Hz between Mt Rainier and Mt Adams, east of Mount St Helens. The latter may reflect large-scale crustal plumbing of the arc between volcanic centers. In subsequent analyses these ANT results will be jointly inverted with receiver functions in order to further resolve crustal and upper mantle structure.

  5. Eruption-triggered avalanche, flood, and lahar at Mount St. Helens - Effects of winter snowpack

    USGS Publications Warehouse

    Waitt, R.B., Jr.; Pierson, T.C.; MacLeod, N.S.; Janda, R.J.; Voight, B.; Holcomb, R.T.

    1983-01-01

    An explosive eruption of Mount St. Helens on 19 March 1982 had substantial impact beyond the vent because hot eruption products interacted with a thick snowpack. A blast of hot pumice, dome rocks, and gas dislodged crater-wall snow that avalanched through the crater and down the north flank. Snow in the crater swiftly melted to form a transient lake, from which a destructive flood and lahar swept down the north flank and the North Fork Toutle River.

  6. The Evolution and Role of the Saharan Air Layer During Hurricane Helene (2006)

    NASA Technical Reports Server (NTRS)

    Braun, Scott A.; Sippel, Jason A.; Shie, Chung-Lin; Boller, Ryan A.

    2013-01-01

    The Saharan air layer (SAL) has received considerable attention in recent years as a potential negative influence on the formation and development of Atlantic tropical cyclones. Observations of substantial Saharan dust in the near environment of Hurricane Helene (2006) during the National Aeronautics and Space Administration (NASA) African Monsoon Multidisciplinary Activities (AMMA) Experiment (NAMMA) field campaign led to suggestions about the suppressing influence of the SAL in this case. In this study, a suite of satellite remote sensing data, global meteorological analyses, and airborne data are used to characterize the evolution of the SAL in the environment of Helene and assess its possible impact on the intensity of the storm. The influence of the SAL on Helene appears to be limited to the earliest stages of development, although the magnitude of that impact is difficult to determine observationally. Saharan dust was observed on the periphery of the storm during the first two days of development after genesis when intensification was slow. Much of the dust was observed to move well westward of the storm thereafter, with little SAL air present during the remainder of the storm's lifetime and with the storm gradually becoming a category-3 strength storm four days later. Dry air observed to wrap around the periphery of Helene was diagnosed to be primarily non-Saharan in origin (the result of subsidence) and appeared to have little impact on storm intensity. The eventual weakening of the storm is suggested to result from an eyewall replacement cycle and substantial reduction of the sea surface temperatures beneath the hurricane as its forward motion decreased.

  7. Multi-scale roughness spectra of Mount St. Helens debris flows

    NASA Technical Reports Server (NTRS)

    Austin, Richard T.; England, Anthony W.

    1993-01-01

    A roughness spectrum allows surface structure to be interpreted as a sum of sinusoidal components with differing wavelengths. Knowledge of the roughness spectrum gives insight into the mechanisms responsible for electromagnetic scattering at a given wavelength. Measured spectra from 10-year-old primary debris flow surfaces at Mount St. Helens conform to a power-law spectral model, suggesting that these surfaces are scaling over the measured range of spatial frequencies. Measured spectra from water-deposited surfaces deviate from this model.

  8. A decade of dome growth at Mount St. Helens, 1980-90

    USGS Publications Warehouse

    Swanson, D.A.

    1990-01-01

    The growth of the dacite dome at Mount St. Helens between 1980 and 1986 has been more intensively studied than that of any other dome-building eruption. The growth has been complex in detail, but remarkably regular overall. This paper summarizes some of what has been learned and provides many references to additional information. Whether dome building has ended is an open question, particularly in view of the renewed, though minor, explosive activity of late 1989 and early 1990. -Author

  9. Deposition and dose from the 18 May 1980 eruption of Mount St. Helens

    NASA Technical Reports Server (NTRS)

    Peterson, K. R.

    1982-01-01

    The downwind deposition and radiation doses was calculated for the tropospheric part of the ash cloud from the May 18, 1980 eruption of Mount St. Helens, by using a large cloud diffusion model. The naturally occurring radionnuclides of radium and thorium, whose radon daughters normally seep very slowly from the rocks and soil, were violently released to the atmosphere. The largest dose to an individual from these nuclides is small, but the population dose to those affected by the radioactivity in the ash is about 100 person rem. This population dose from Mount St. Helens is much greater than the annual person rem routinely released by a typical large nuclear power plant. It is estimated that subsequent eruptions of Mount St. Helens have doubled or tripled the person rem calculated from the initial large eruption. The long range global ash deposition of the May 18 eruption is estimated through 1984, by use of a global deposition model. The maximum deposition is nearly 1000 kg square km and occurs in the spring of 1981 over middle latitudes of the Northern Hemisphere.

  10. Eruptive activity at Mount St Helens, Washington, USA, 1984-1988: a gas geochemistry perspective

    USGS Publications Warehouse

    McGee, K.A.; Sutton, A.J.

    1994-01-01

    The results from two different types of gas measurement, telemetered in situ monitoring of reducing gases on the dome and airborne measurements of sulfur dioxide emission rates in the plume by correlation spectrometry, suggest that the combination of these two methods is particularly effective in detecting periods of enhanced degassing that intermittently punctuate the normal background leakage of gaseous effluent from Mount St Helens to the atmosphere. Gas events were recorded before lava extrusion for each of the four dome-building episodes at Mount St Helens since mid-1984. For two of the episodes, precursory reducing gas peaks were detected, whereas during three of the episodes, COSPEC measurements recorded precursory degassing of sulfur dioxide. During one episode (October 1986), both reducing gas monitoring and SO2 emission rate measurements simultaneously detected a large gas release several hours before lava extrusion. Had both types of gas measurements been operational during each of the dome-building episodes, it is thought that both would have recorded precursory signals for all four episodes. Evidence from the data presented herein suggests that increased degassing at Mount St Helens becomes detectable when fresh upward-moving magma is between 2 km and a few hundred meters below the base of the dome and between about 60 and 12 hours before the surface extrusion of lava. ?? 1994 Springer-Verlag.

  11. Distribution of melt beneath Mount St Helens and Mount Adams inferred from magnetotelluric data

    USGS Publications Warehouse

    Hill, G.J.; Caldwell, T.G.; Heise, W.; Chertkoff, D.G.; Bibby, H.M.; Burgess, M.K.; Cull, J.P.; Cas, Ray A.F.

    2009-01-01

    Three prominent volcanoes that form part of the Cascade mountain range in Washington State (USA)Mounts StHelens, Adams and Rainierare located on the margins of a mid-crustal zone of high electrical conductivity1,5. Interconnected melt can increase the bulk conductivity of the region containing the melt6,7, which leads us to propose that the anomalous conductivity in this region is due to partial melt associated with the volcanism. Here we test this hypothesis by using magnetotelluric data recorded at a network of 85 locations in the area of the high-conductivity anomaly. Our data reveal that a localized zone of high conductivity beneath thisvolcano extends downwards to join the mid-crustal conductor. As our measurements were made during the recent period of lava extrusion at Mount St Helens, we infer that the conductivity anomaly associated with the localized zone, and by extension with the mid-crustal conductor, is caused by the presence of partial melt. Our interpretation is consistent with the crustal origin of silicic magmas erupting from Mount St Helens8, and explains the distribution of seismicity observed at the time of the catastrophic eruption in 1980 (refs9, 10). ?? 2009 Macmillan Publishers Limited. All rights reserved.

  12. Proximal ecological effects of the 1980 eruptions of Mount St. Helens

    NASA Technical Reports Server (NTRS)

    Swanson, F. J.

    1988-01-01

    The diversity of ecosystems and volcanic processes involved in the 1980 eruptions of Mount St. Helens, southwest Washington, provide an excellent setting for examining effects of volcanic events on ecosystems. These eruptions included a lateral blast, debris avalanche, mudflows, pyroclastic flows, and airfall tephra. Affected ecosystems within 30 km of the vent were lakes, streams, upland and riparian forest, and meadows. Ecological disturbances imposed by the Mount St. Helens events were predominantly physical, rather than climatic or chemical which are the dominant classes of disturbances considered in analysis of global catastrophes. Analysis of ecosystem response to disturbance should be based on consideration of composition and structure of the predisturbance system in terms that represent potential survivability of organisms, mechanisms in the primary disturbance, initial survivors, secondary disturbances arising from the primary disturbance and the biological responses to secondary disturbances, invasion of the site by new propagules, interactions among secondary disturbance processes and surviving and invading organisms. Predicting ecosystem response to disturbance is enchanced by considering the mechanisms of disturbance rather than type of disturbance. In the 1980 Mount St. Helens events, the disturbance types, involved primarily the mechanisms of sedimentation, heating, and shear stress. Each disturbance type involved one or more mechanisms. Ecosystem response varied greatly across the landscape. Analysis of ecosystem response to disturbance, regardless of type, should include detailed consideration of the properties of individual species, primary and secondary disturbance mechanisms, and their distributions across landscapes.

  13. The dust environment surrounding the E-ring moons Dione, Helene and Polydeuce

    NASA Astrophysics Data System (ADS)

    Moldenhawer, T.; Hoffmann, H.; Seiß, M.; Sachse, M.; Spahn, F.

    2015-10-01

    Compared to the dust clouds around three of the Galilean satellites of Jupiter, no clear Saturnian pendants have been found yet by the CDA detector aboardthe Cassini spacecraft. However, three dust tori and arcs have been detected along the orbits of Pallene, Methone and Anthe in ISS images [1] and the Pallene dust torus was confirmed by in situ CDA measurements [4]. These observations have sparked interest whether the small co-orbital companions to E-ring moons like Dione or Thetys are efficient dust sources. We simulate the motion of dust particles, which originate from hypervelocity impacts of micrometeoroids onto Dione, Helene and Polydeuce [2]. Gravity, Lorentz force, solar radiation pressure and plasma drag are considered for the dynamic evolution of small dust particles. Assuming a steady state distribution, we scale the phase space data with dust production rates based on recent IDP measurements at Saturn [3]. We will present dust particle number densities along the orbits of Dione, Helene and Polydeuce and we will make predictions for the Cassini flybys of Helene and Polydeuce, which take place in the summer and fall this year.

  14. 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.

  15. A new tree-ring date for the "floating island" lava flow, Mount St. Helens, Washington

    USGS Publications Warehouse

    Yamaguchi, D.K.; Hoblitt, R.P.; Lawrence, D.B.

    1990-01-01

    Anomalously narrow and missing rings in trees 12 m from Mount St. Helens' "floating island" lava flow, and synchronous growth increases in trees farther from the flow margin, are evidence that this andesitic flow was extruded between late summer 1799 and spring 1800 a.d., within a few months after the eruption of Mount St. Helens' dacitic layer T tephra. For ease of reference, we assign here an 1800 a.d. date to this flow. The new date shows that the start of Mount St. Helens' Goat Rocks eruptive period (1800-1857 a.d.) resembled the recent (1980-1986) activity in both petrochemical trends and timing. In both cases, an initial explosive eruption of dacite was quickly succeeded by the eruption of more mafic lavas; dacite lavas then reappeared during an extended concluding phase of activity. This behavior is consistent with a recently proposed fluid-dynamic model of magma withdrawal from a compositionally zoned magma chamber. ?? 1990 Springer-Verlag.

  16. Deposition and dose from the May 18, 1980 eruption of Mount St. Helens

    SciTech Connect

    Peterson, K.R.

    1980-11-01

    The downwind deposition and radiation dose have been calculated for the tropospheric part of the ash cloud from the May 18, 1980 eruption of Mount St. Helens, using a large-cloud diffusion model. At that time the naturally occurring radionuclides of radium and thorium, whose radon daughters normally seep very slowly from the rocks and soil, were violently released to the atmosphere. The largest dose to an individual from these nuclides is small (in the microrem range), but the population dose to those affected by the radioactivity in the ash is about 100 person-rem. This population dose from Mount St. Helens is much greater than the annual person-rem routinely released by a typical large nuclear power plant. It is estimated that subsequent eruptions of Mount St. Helens have doubled or tripled the person-rem calculated for the initial large eruption; this total population dose is about the same as the lower-bound estimate of the population dose from the 1979 accident at the Three Mile Island nuclear power plant. The long-range global ash deposition of the May 18 eruption has been estimated through 1984, using a global deposition model. The maximum deposition is nearly 1000 kg/km/sup 2/ and occurs in the spring of 1981 over middle latitudes of the Northern Hemisphere.

  17. Mount St. Helens, 1980 to now—what’s going on?

    USGS Publications Warehouse

    Dzurisin, Daniel; Driedger, Carolyn L.; Faust, Lisa M.

    2013-01-01

    Mount St. Helens seized the world’s attention in 1980 when the largest historical landslide on Earth and a powerful explosive eruption reshaped the volcano, created its distinctive crater, and dramatically modified the surrounding landscape. An enormous lava dome grew episodically in the crater until 1986, when the volcano became relatively quiet. A new glacier grew in the crater, wrapping around and partly burying the lava dome. From 1987 to 2003, sporadic earthquake swarms and small steam explosions indicated that magma (molten rock) was being replenished deep underground. In 2004, steam-and-ash explosions heralded the start of another eruption. A quieter phase of continuous lava extrusion followed and lasted until 2008, building a new dome and doubling the volume of lava on the crater floor. Scientists with the U.S. Geological Survey and University of Washington’s Pacific Northwest Seismograph Network maintain constant watch for signs of renewed activity at Mount St. Helens and other Cascade volcanoes. Now is an ideal time for both actual and virtual visitors to Mount St. Helens to learn more about dramatic changes taking place on and beneath this active volcano.

  18. Catalog of Mount St. Helens 2004 - 2005 Tephra Samples with Major- and Trace-Element Geochemistry

    USGS Publications Warehouse

    Rowe, Michael C.; Thornber, Carl R.; Gooding, Daniel J.; Pallister, John S.

    2008-01-01

    This open-file report presents a catalog of information about 135 ash samples along with geochemical analyses of bulk ash, glass and individual mineral grains from tephra deposited as a result of volcanic activity at Mount St. Helens, Washington, from October 1, 2004 until August 15, 2005. This data, in conjunction with that in a companion report on 2004?2007 Mount St. Helens dome samples by Thornber and others (2008a) are presented in support of the contents of the U.S. Geological Survey Professional Paper 1750 (Sherrod and others, ed., 2008). Readers are referred to appropriate chapters in USGS Professional Paper 1750 for detailed narratives of eruptive activity during this time period and for interpretations of sample characteristics and geochemical data presented here. All ash samples reported herein are currently archived at the David A. Johnston Cascades Volcano Observatory in Vancouver, Washington. The Mount St. Helens 2004?2005 Tephra Sample Catalogue along with bulk, glass and mineral geochemistry are tabulated in 6 worksheets of the accompanying Microsoft Excel file, of2008-1131.xls. Samples in all tables are organized by collection date. Table 1 is a detailed catalog of sample information for tephra deposited downwind of Mount St. Helens between October 1, 2004 and August 18, 2005. Table 2 provides major- and trace-element analyses of 8 bulk tephra samples collected throughout that interval. Major-element compositions of 82 groundmass glass fragments, 420 feldspar grains, and 213 mafic (clinopyroxene, amphibole, hypersthene, and olivine) mineral grains from 12 ash samples collected between October 1, 2004 and March 8, 2005 are presented in tables 3 through 5. In addition, trace-element abundances of 198 feldspars from 11 ash samples (same samples as major-element analyses) are provided in table 6. Additional mineral and bulk ash analyses from 2004 and 2005 ash samples are published in chapters 30 (oxide thermometry; Pallister and others, 2008), 32

  19. Effects of the 1980 eruption of Mount St Helens on the limnological characteristics of selected lakes in western Washington

    USGS Publications Warehouse

    Embrey, S.S.; Dion, N.P.

    1988-01-01

    The 1980 eruption of Mount St. Helens provided the opportunity to study its effect on the physical, chemical, and biological characteristics of lakes near the volcano, and to describe two newly created lakes. Concentrations of dissolved solids and organic carbon, measured in June 1980, had increased from 2 to 30 times those observed in the 1970 's in Spirit, St. Helens, and Venus Lakes. Water in the lakes was altered from preeruption calcium-bicarbonate types to calcium-sulfate, calcium sulfate-chloride, or lake surface, as in St. Helens Lake; transparency in Venus Lake had improved to a depth of 24 ft by 1982. Spirit Lake was anoxic into fall 1980, but had reaerated to 5.2 mg/L of dissolved oxygen by May 1981. Phytoplankton communities in existing lakes in the blast zone in 1980 were primarily green and bluegreen algae; diatoms were sparse until summer 1982. Small numbers of zooplankton in Spirit, St. Helens, and Venus Lakes, compared to numbers in Walupt and Fawn Lakes, may indicate some post-eruption mortality. Rotifers were absent from lakes in the blast zone, but by 1981 were observed in all the lakes. The recovery of the physical, chemical, and biological characteristics of the lakes will depend on stabilization of the surrounding environment and biological processes within each lake. Excluding Spirit Lake, it is estimated that St. Helens Lake would be the slowest to recover and Venus Lake the fastest. (USGS)

  20. 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.

    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.

  1. Large-amplitude traveling ionospheric distrubance produced by the May 18, 1980, explosion of Mount St. Helens

    SciTech Connect

    Roberts, D.H.; Klobuchar, J.A.; Fougere, P.F.; Hendrickson, D.H.

    1982-08-01

    A remarkable long-lived, large-scale traveling ionospheric disturbance (TID), excited by the May 18, 1980, explosion of Mount St. Helens, has been detected in total electron content monitor data. Oscillatory perturbations in the electron column density of the ionosphere with amplitudes about 10% of the nominal daytime content were detected at three stations whose ionospheric penetration points lie between 1610 and 1890 km from Mount St. Helens. Smaller perturbations were detected at five of six additional stations between 3760 and 4950 km away. The period of the TID increased linearly with great-circle distance from Mount St. Helens, ranging from roughly-equal37 min at the nearest station to roughly-equal116 min at the most distant one. The TID persisted for at least four cycles at the three close stations and three cycles at the more distant stations and was qualitatively similar to TID's produced by the low-altitude thermonuclear detonations of the 1960's. The disturbance front of this TID accelerated from an average velocity of roughly-equal350 m/s between Mt. St. Helens and the close stations to an average velocity of roughly-equal550 m/s to the more distant ones.A model based on the free wave response of an isothermal atmosphere to a point disturbance provides a good fit to the data at the three closest stations, but no such model can account for all of the data. Modeling of the long-distance behavior of the Mount St. Helens TID in terms of upper-atmosphere guided gravity waves is complicated by the requirement of exciting them by a ground-level explosion. There was no evidence for a strong supersonic shock wave in the ionosphere. As a result, the Mount St. Helens disturbance may prove to be a cleaner test of detailed theories of the point excitation and propagation of gravity waves in a realistic atmosphere than were TID's excited by thermonuclear weapons.

  2. VP Structure of Mount St. Helens, Washington, USA, imaged with local earthquake tomography

    USGS Publications Warehouse

    Waite, G.P.; Moran, S.C.

    2009-01-01

    We present a new P-wave velocity model for Mount St. Helens using local earthquake data recorded by the Pacific Northwest Seismograph Stations and Cascades Volcano Observatory since the 18 May 1980 eruption. These data were augmented with records from a dense array of 19 temporary stations deployed during the second half of 2005. Because the distribution of earthquakes in the study area is concentrated beneath the volcano and within two nearly linear trends, we used a graded inversion scheme to compute a coarse-grid model that focused on the regional structure, followed by a fine-grid inversion to improve spatial resolution directly beneath the volcanic edifice. The coarse-grid model results are largely consistent with earlier geophysical studies of the area; we find high-velocity anomalies NW and NE of the edifice that correspond with igneous intrusions and a prominent low-velocity zone NNW of the edifice that corresponds with the linear zone of high seismicity known as the St. Helens Seismic Zone. This low-velocity zone may continue past Mount St. Helens to the south at depths below 5??km. Directly beneath the edifice, the fine-grid model images a low-velocity zone between about 2 and 3.5??km below sea level that may correspond to a shallow magma storage zone. And although the model resolution is poor below about 6??km, we found low velocities that correspond with the aseismic zone between about 5.5 and 8??km that has previously been modeled as the location of a large magma storage volume. ?? 2009 Elsevier B.V.

  3. Distribution of Mount St. Helens dust inferred from satellites and meteorological data

    NASA Technical Reports Server (NTRS)

    Laver, J. D.

    1982-01-01

    Visible and infrared pictures from two Geostationary Operational Environmental Satellite Systems satellites, in circular orbits at about 19,000 nautical miles, are available continuously at approximately 30 minute intervals. Still pictures and film loops from this system vividly depict the events associated with the May 18, 1980 eruption of Mount St. Helens. The initial explosion, shock wave, and visible horizontal dust distribution during the following week are readily apparent. Meteorological wind and height fields permit the inference of the vertical distribution of volcanic dust as well as explain the atmospheric behavior which caused the visible and nonvisible dust distribution.

  4. Eruption prediction aided by electronic tiltmeter data at mount st. Helens.

    PubMed

    Dzurisin, D; Westphal, J A; Johnson, D J

    1983-09-30

    Telemetry from electronic tiltmeters in the crater at Mount St. Helens contributed to accurate predictions of all six effusive eruptions from June 1981 to August 1982. Tilting of the crater floor began several weeks before each eruption, accelerated sharply for several days, and then abruptly changed direction a few minutes to days before extrusion began. Each episode of uplift was caused by the intrusion of magma into the lava dome from a shallow source, causing the dome to inflate and eventually rupture. Release of magma pressure and increased surface loading by magma added to the dome combined to cause subsidence just prior to extrusion. PMID:17759009

  5. Characterization of organic contaminants in environmental samples associated with mount St. Helens 1980 volcanic eruption

    USGS Publications Warehouse

    Pereira, W.E.

    1982-01-01

    Volcanic ash, surface-water, and bottom-material samples obtained in the vicinity of Mount St. Helens after the May 18, 1980, eruption were analyzed for organic contaminants by using capillary gas chromatography-mass spectrometry-computer techniques. Classes of compounds identified include n-alkanes, fatty acids, dicarboxylic acids, aromatic acids and aldehydes, phenols, resin acids, terpenes, and insect juvenile hormones. The most probable source of these compounds is from pyrolysis of plant and soil organic matter during and after the eruption. The toxicity of selected compounds and their environmental significance are discussed.

  6. Direct temperature measurements of deposits, Mount St. Helens, Washington, 1980-1981

    USGS Publications Warehouse

    Banks, N.G.; Hoblitt, R.P.

    1996-01-01

    A program of temperature studies of the eruptive products of Mount St. Helens was established May 20, 1980, just 2 days after the catastrophic eruption of May 18. In general, the more recent deposits were emplaced at higher temperatures than the earlier ones. Emplacement temperatures of deposits of the debris avalanche of May 18 ranged from about 70 to 100 deg C, of the directed blast of May 18 from about 100 to 325 deg C (depending on azimuth from the vent), and of the subsequent pumiceous pyroclastic flows from about 300 to 850 deg C. Temperatures of the summit domes were as high as 897 deg C.

  7. 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.

  8. Correlation between atmospheric precipitation and recent explosions at Mount St. Helens, Washington

    USGS Publications Warehouse

    Mastin, L.

    1992-01-01

    Scientists attribute the recent small explosion-like seismic signals at Mount St. Helens to either the geyser-like flashing of superheated groundwater to steam or the release of magmatic gas from the cooling magma system, or both. The contribution of magmaic gas in these events is not currently known. If meteoric water from rain or melting snow is the source, however, we might expect these events to occur most frequently during the rainy season, perhaps even during or immediately following individual storms. 

  9. Predicting eruptions at mount st. Helens, june 1980 through december 1982.

    PubMed

    Swanson, D A; Casadevall, T J; Dzurisin, D; Malone, S D; Newhall, C G; Weaver, C S

    1983-09-30

    Thirteen eruptions of Mount St. Helens between June 1980 and December 1982 were predicted tens of minutes to, more generally, a few hours in advance. The last seven of these eruptions, starting with that of mid-April 1981, were predicted between 3 days and 3 weeks in advance. Precursory seismicity, deformation of the crater floor and the lava dome, and, to a lesser extent, gas emissions provided telltale evidence of forthcoming eruptions. The newly developed capability for prediction reduced risk to life and property and influenced land-use decisions. PMID:17759006

  10. Biological responses of lakes in the mount st. Helens blast zone.

    PubMed

    Wissmar, R C; Devol, A H; Staley, J T; Sedell, J R

    1982-04-01

    Loadings of dissolved organics and suspended particulates from destroyed forests and volcanic debris produced by the 18 May 1980 eruption of Mount St. Helens altered the trophic structure of many blast zone lakes to the extent that anoxic conditions and chemoorganotrophic and chemolithotrophic microorganisms prevailed. High bacterial counts and high adenosine triphosphate concentrations were directly related to enhanced concentrations of dissolved organic carbon, and plankton chlorophyll a was inversely related to light extinction. The recovery of these lakes to the preeruption state appears dependent upon the oxidation of organics and the stabilization of watersheds. PMID:17736249

  11. Problems in the climatology of the 1980 Mount St. Helens eruptions. [surface heat and water budgets

    NASA Technical Reports Server (NTRS)

    Critchfield, H. J.

    1982-01-01

    A brief review of the effects of climate and weather on the 1980 Mount St. Helens eruptions and the subsequent dispersion of ash and gases and the reciprocal influences of the eruptions on climate and climatology is presented. The effects of mesoscale destruction of snow fields and vegetation, a revised mountain profile, and ash deposits are addressed along with impacts on hemispheric climate and disruption of normal climatological observations, in the areas directly affected by the explosions and ashfall. Environmental and economic consequences are also considered.

  12. Chemical changes of lakes within the Mount St. Helens blast zone

    SciTech Connect

    Wissmar, R.C.; Devol, A.H.; Nevissi, A.E.; Sedell, J.R.

    1982-01-01

    Differences in the dissolved chemistry of lakes devastated by the 18 May 1980 eruption of Mount St. Helens are attributable to location relative to the lateral blast trajectory of the eruption and to the emplacement of mineral deposits. Elemental enrichment ratios of pre- and posteruption measurements for Spirit Lake and comparisons of the chemical concentrations and elemental ratios for lakes inside and outside the blast zone reflect the influences of the dissolution of magmatic and lithic deposits. The pH changes were minor because of buffering by carbonic acid and reactions involving mineral alteration, dissolved organics, and biological processes.

  13. Airborne studies of the emissions from the volcanic eruptions of Mount St. Helens

    SciTech Connect

    Hobbs, P.V.; Radke, L.F.; Eltgroth, M.W.; Hegg, D.A.

    1981-01-01

    The concentrations of particles less than 10 micrometers in diameter in the ash emissions from Mount St. Helens have been more than 1000 times greater than those in the ambient air. Mass loadings of particles less than 2 micrometers in diameter were generally several hundred micrograms per cubic meter. In the ash clouds, produced by the large eruption on 18 May 1980, the concentrations of several trace gases generally were low. In other emissions, significant, but variable, concentrations of sulfur gases were measured. The 18 May eruption produced nuees ardentes, lightning flashes, and volcanic hail.

  14. Evaluation of radon progeny from Mount St. Helens eruptions. Final report

    SciTech Connect

    Lepel, E.A.; Olsen, K.B.; Thomas, V.W.; Eichner, F.N.

    1982-09-01

    A network of twelve monitoring sites around Mount St. Helens was established to evaluate possible short-lived radioactivity in the fallen ash. Seven sites were located near major population centers of Washington and Oregon, and five sites were located within 80 km of the volcano. Each site monitored the radioactivity present by the use of thermoluminescent dosimeters which recorded the total exposure to radioactivity over the exposure period. Eruptions occurring on July 22, August 7, and October 16 to 18, 1980 were monitored. No statistically significant quantities of measurable radon daughters were observed.

  15. Chemical changes of lakes within the mount st. Helens blast zone.

    PubMed

    Wissmar, R C; Devol, A H; Nevissi, A E; Sedell, J R

    1982-04-01

    Differences in the dissolved chemistry of lakes devastated by the 18 May 1980 eruption of Mount St. Helens are attributable to location relative to the lateral blast trajectory of the eruption and to the emplacement of mineral deposits. Elemental enrichment ratios of pre- and posteruption measurements for Spirit Lake and comparisons of the chemical concentrations and elemental ratios for lakes inside and outside the blast zone reflect the influences of the dissolution of magmatic and lithic deposits. The pH changes were minor because of buffering by carbonic acid and reactions involving mineral alteration, dissolved organics, and biological processes. PMID:17736248

  16. Measurements of the stratospheric plume from the Mount St. Helens eruption: radioactivity and chemical composition

    SciTech Connect

    Leifer, R.; Hinchliffe, L.; Fisenne, I.; Franklin, H.; Knutson, E.; Olden, M.; Sedlacek, W.; Mroz, E.; Cahill, T.

    1981-11-20

    Gas measurements made in the stratospheric plume from the eruption of Mount St. Helens on 18 May 1980 were not consistent with a reported large injection of radon-222 into the atmosphere. No enrichment in the volatile element polonium was found in filter samples, and the ratio of polonium-210 to lead-210 was not different from background values. Data obtained with an experimental impactor, flown shortly after the eruption, showed an increase of 10/sup 3/ in the stratospheric number concentration of submicrometer sulfate particles compared to concentrations before the eruption.

  17. Remanent magnetization of ash from the 18 May 1980 eruption of Mount St. Helens

    SciTech Connect

    Steele, W.K.

    1981-03-01

    Ash from the May 1980 eruption of Mount St. Helens deposited from air faithfully records the direction of the local geomagnetic field in eastern Washington, whereas ash settled from suspension in water in fluvial environments exhibits significant inclination and current-rotation errors in magnetic direction similar to those reported in other subaqueously deposited sediments. The current-rotation errors are associated with partial alignment of the major axes of magnetic susceptibility in the direction of water currents. Subaerial deposition produces strong stable remanent magnetization in ash with or without postdepositional wetting by rain.

  18. Changes in stratospheric water vapor associated with the Mount St. Helens eruption

    SciTech Connect

    Murcray, D.G.; Murcray, F.J.; Barker, D.B.; Mastenbrook, H.J.

    1981-01-01

    A frost point hygrometer designed for aircraft operation was included in the complement of instruments assembled for the NASA U-2 flights through the plume of Mount St. Helens. Measurements made on the 22 May flight showed the water vapor to be closely associated with the aerosol plume. The water vapor mixing ratio by mass in the plume was as high as 40 x 10/sup -6/. This compares with values of 2 x 10/sup -6/ to 3 x 10/sup -6/ outside of the plume.

  19. Measurements of the stratospheric plume from the mount st. Helens eruption: radioactivity and chemical composition.

    PubMed

    Leifer, R; Hinchliffe, L; Fisenne, I; Franklin, H; Knutson, E; Olden, M; Sedlacek, W; Mroz, E; Cahill, T

    1981-11-20

    Gas measurements made in the stratospheric plume from the eruption of Mount St. Helens on 18 May 1980 were not consistent with a reported large injection of radon-222 into the atmosphere. No enrichment in the volatile element polonium was found in filter samples, and the ratio of polonium-210 to lead-210 was not different from background values. Data obtained with an experimental impactor, flown shortly after the eruption, showed an increase of 10(3) in the stratospheric number concentration of submicrometer sulfate particles compared to concentrations before the eruption. PMID:17782443

  20. The Stars Belong to Everyone: Astronomer and Science Writer Dr. Helen Sawyer Hogg (1905-1993)

    NASA Astrophysics Data System (ADS)

    Cahill, Maria J.

    2011-05-01

    University of Toronto astronomer and science writer Helen Sawyer Hogg (President of the AAVSO 1939-41) served her field through research, teaching, and administrative leadership. Additionally, she reached out to students and the public through her Toronto Star newspaper column entitled "With the Stars" for thirty years; she wrote The Stars Belong to Everyone, a book that speaks to a lay audience; she hosted a successful television series entitled Ideas; and she delivered numerous speeches at scientific conferences, professional women's associations, school programs, libraries, and other venues. This paper will illumine her life and the personal and professional forces that influenced her work.

  1. Terpenoid marker compounds derived from biogenic precursors in volcanic ash from Mount St. Helens, Washington

    USGS Publications Warehouse

    Pereira, W.E.; Rostad, C.E.

    1983-01-01

    A volcanic-ash sample obtained after the 1980 eruption of Mount St. Helens, Washington, was analyzed for cyclic terpenoid organic compounds and polycyclic aromatic hydrocarbons using capillary gas chromatography-mass spectrometry-computer techniques. Various tricyclic diterpenoid acids and hydrocarbons were identified including dehydroabietic acid, dehydroabietin, dehydroabietane, simonellite, and retene. Preliminary evidence indicates that these compounds were derived from forest soils or atmospheric aerosols or both in the vicinity of coniferous forests. A diagenetic scheme involving three possible pathways for the conversion of abietic acid to retene is presented. ?? 1983.

  2. The Stars Belong to Everyone: Astronomer and Science Writer Helen Sawyer Hogg (1905-1993)

    NASA Astrophysics Data System (ADS)

    Cahill, Maria J.

    2012-06-01

    As a scientist and science educator, Helen Sawyer Hogg served astronomy, and especially variable star astronomy, in diverse ways while raising a family. Her long interest in and support of the AAVSO over many years took place in the context of not only that busy scientific and writing career, but also one of personal struggle to achieve parity as a female in a largely male profession. This biographical sketch demonstrates that her path to eventual status as “the Canadian face of astronomy” was both difficult and filled with uncertainty.

  3. Helen Flanders Dunbar, John Dewey, and clinical pragmatism: reflections on method in psychosomatic medicine and bioethics.

    PubMed

    Hart, Curtis W

    2002-01-01

    This article outlines the method utilized by physicians and major figures in the founding of Clinical Pastoral Education, Helen Flanders Dunbar, in her work of 1943, Psychosomatic Diagnosis, and relates it to the currently evolving approach in bioethics known as clinical pragmatism. It assesses Dewey's influence on both Dunbar in psychosomatic medicine and clinical pragmatism in bioethics, and illustrates the breadth of influence of the school of philosophical thought known as pragmatism with which Dewey's name and those of William James and Charles Sanders Pierce are most often identified. PMID:12385140

  4. Eruption prediction aided by electronic tiltmeter data at Mount St. Helens

    USGS Publications Warehouse

    Dzurisin, D.; Westphal, J.A.; Johnson, Daniel J.

    1983-01-01

    Telemetry from electronic tiltmeters in the crater at Mount St. Helens contributed to accurate predictions of all six effusive eruptions from June 1981 to August 1982. Tilting of the crater floor began several weeks before each eruption, accelerated sharply for several days, and then abruptly changed direction a few minutes to days before extrusion began. Each episode of uplift was caused by the intrusion of magma into the lava dome from a shallow source, causing the dome to inflate and eventually rupture. Release of magma pressure and increased surface loading by magma added to the dome combined to cause subsidence just prior to extrusion.

  5. Comparison of Mount Saint Helens volcanic eruption to a nuclear explosion. Technical note

    SciTech Connect

    Gould, K.E.

    1981-01-01

    The phenomena and effects of airblast, ground shock, thermal radiation, cratering and ejecta, and debris cloud and deposition from the eruption of Mt. St. Helens were compared to those that would result from a nuclear explosion to determine if phenomena or effects were analogous and thus might provide useful data for military nuclear weapon effects studies. It is concluded that the phenomena are not analogous. In particular, airblast destruction was caused by clouds of ash driven by subsonic winds, rather than by a supersonic shock wave that would be the damage mechanism of a nuclear explosion. Because of the lack of analogy between the eruption and nuclear explosion phenomena, it appears questionable that any of the effects are analogous; therefore, it is unlikely that anything more of military interest can be gained from studying the effects of the eruption. However, key contacts for further information on the eruption and the associated research studies are given. The comparison of the eruption of Mt. St. Helens to the explosion of a 10- to 20-megaton nuclear weapon is misleading. Such comparisons serve no useful purpose and should be avoided.

  6. Recovery of lakes in the 1980 blast zone of Mount St. Helens

    SciTech Connect

    Wissmar, R.C. )

    1990-11-01

    Over the past 10 years, following the catastrophic 1980 eruption of Mount St. Helens, considerable research has been conducted on altered and newly created lake ecosystems in different depositional regions of the blast zone. Impact and recovery characteristics have been followed for the altered Spirit Lake and two newly created lakes S. F. Castle and Coldwater Lakes. During the 1980 eruption, Spirit Lake was directly impacted by debris avalanches and pyroclastic flows. The unique characteristics of the Mount St. Helens volcanic eruption and geochemistry, such as low inputs of sulfate and high loadings of organics from devastated forests to lakes, combined to form chemical environments favorable to biological activity. Even though weathering, organic and microbial reactions were evidently the important processes regulating alkalinity of these lakes, patterns of changes in pH, total alkalinity, and dissolved organic carbon and changes in microbial assemblages and processes also suggested a sequence of biological reactions that occurred during the early recovery period of 1980 and 1981. The biological recovery of the lakes via succession of microbial reactions suggests a tendency for the higher energy producing reactions to dominate lesser energy producing reactions. As turbid and high suspended particulate matter levels decreased, phytoplankton primary production increased to produce mixed bacteria-phytoplankton-zooplankton communities.

  7. Sediment data for streams near Mount St. Helens, Washington; Volume 1, 1980 water year

    USGS Publications Warehouse

    Dinehart, Randal L.; Ritter, John R.; Knott, J.M.

    1981-01-01

    This report presents fluvial sediment data collected primarily in response to the eruption of Mount St. Helens. To monitor the sediment transported by streams in the Mount St. Helens area and the particle-size distributions of the sediment, the Water Resources Division of the U.S. Geological Survey initially established 18 fluvial sediment stations. In this report, concentrations and discharges of suspended sediment are given for 16 fluvial-sediment stations (5 are in the Toutle River basin) and for 11 miscellaneous sampling sites. Also included are particle-size distributions of suspended sediment and bed material, water discharge, and water temperature for many of the sediment samples. Daily sediment discharges for the period May 18 to September 30 were calculated for Toutle River at Highway 99 near Castle Rock and Cowlitz River at Castel Rock. Over 150 million tons of sediment are estimated to have passed the Toutle River at Highway 99 station on May 18-19, 1980. High concentrations of suspended sediment persisted at several stations throughout the spring and summer of 1980. (USGS)

  8. Posteruption glacier development within the crater of Mount St. Helens, Washington, USA

    USGS Publications Warehouse

    Schilling, S.P.; Carrara, P.E.; Thompson, R.A.; Iwatsubo, E.Y.

    2004-01-01

    The cataclysmic eruption of Mount St. Helens on May 18, 1980, resulted in a large, north-facing amphitheater, with a steep headwall rising 700 m above the crater floor. In this deeply shaded niche a glacier, here named the Amphitheater glacier, has formed. Tongues of ice-containing crevasses extend from the main ice mass around both the east and the west sides of the lava dome that occupies the center of the crater floor. Aerial photographs taken in September 1996 reveal a small glacier in the southwest portion of the amphitheater containing several crevasses and a bergschrund-like feature at its head. The extent of the glacier at this time is probably about 0.1 km2. By September 2001, the debris-laden glacier had grown to about 1 km2 in area, with a maximum thickness of about 200 m, and contained an estimated 120,000,000 m3 of ice and rock debris. Approximately one-third of the volume of the glacier is thought to be rock debris derived mainly from rock avalanches from the surrounding amphitheater walls. The newly formed Amphitheater glacier is not only the largest glacier on Mount St. Helens but its aerial extent exceeds that of all other remaining glaciers combined. Published by University of Washington.

  9. Zircon reveals protracted magma storage and recycling beneath Mount St. Helens

    USGS Publications Warehouse

    Claiborne, L.L.; Miller, C.F.; Flanagan, D.M.; Clynne, M.A.; Wooden, J.L.

    2010-01-01

    Current data and models for Mount St. Helens volcano (Washington, United States) suggest relatively rapid transport from magma genesis to eruption, with no evidence for protracted storage or recycling of magmas. However, we show here that complex zircon age populations extending back hundreds of thousands of years from eruption age indicate that magmas regularly stall in the crust, cool and crystallize beneath the volcano, and are then rejuvenated and incorporated by hotter, young magmas on their way to the surface. Estimated dissolution times suggest that entrained zircon generally resided in rejuvenating magmas for no more than about a century. Zircon elemental compositions reflect the increasing influence of mafic input into the system through time, recording growth from hotter, less evolved magmas tens of thousands of years prior to the appearance of mafic magmas at the surface, or changes in whole-rock geochemistry and petrology, and providing a new, time-correlated record of this evolution independent of the eruption history. Zircon data thus reveal the history of the hidden, long-lived intrusive portion of the Mount St. Helens system, where melt and crystals are stored for as long as hundreds of thousands of years and interact with fresh influxes of magmas that traverse the intrusive reservoir before erupting. ?? 2010 Geological Society of America.

  10. Trioctahedral vermiculite in a 1980 pyroclastic flow, Mt. St. Helens, Washington

    SciTech Connect

    LaManna, J.M.; Ugolini, F.C.

    1987-03-01

    Trioctahedral vermiculite, previously unreported, is an abundant phyllosilicate in a Mt. St. Helens pyroclastic flow that was emplaced during the 18 May 1980 eruption. The response of this mineral to various treatments suggests its layer charge is approximately 0.6 per O/sub 10/(OH)/sub 2/. In the pyroclastic flow, vermiculite is present in samples collected in 1981 from the surface-to-90-cm depth, but it is present only from 5 to 90 cm deep in samples collected in 1983. The apparent depletion in trioctahedral vermiculite of the 1983 surface (0-1.5 cm) is believed to be caused by weathering due to the prevailing acidic rainfall (pH = 4.0-4.6). One crucial problem in tephritic soils is to establish the origin of the 2:1 phyllosilicates. The authors findings show that these layer silicates, possessing different layer charges, were most likely present with the lithic fragments of the ejecta. Consequently trioctahedral vermiculite and the previously reported saponite present in Mt. St. Helens tephra should be considered detrital minerals.

  11. The mechanisms of fine particle generation and electrification during Mount St. Helens volcanic eruption

    NASA Technical Reports Server (NTRS)

    Cheng, R. J.

    1982-01-01

    Microscopical investigation of volcanic ash collected from ground stations during Mount St. Helens eruptions reveal a distinctive bimodel size distribution with high concentrations of particle ranges at (1) 200-100 microns and (2) 20-0.1 microns. Close examination of individual particles shows that most larger ones are solidified magma particles of porous pumice with numerous gas bubbles in the interior and the smaller ones are all glassy fragments without any detectable gas bubbles. Elemental analysis demonstrates that the fine fragments all have a composition similar to that of the larger pumice particles. Laboratory experiments suggest that the formation of the fine fragments is by bursting of glassy bubbles from a partially solidified surface of a crystallizing molten magma particle. The production of gas bubbles is due to the release of absorbed gases in molten magma particles when solubility decreases during phase transition. Diffusion cloud chamber experiments strongly indicate that sub-micron volcanic fragments are highly hygroscopic and extremely active as cloud condensation nuclei. Ice crystals also are evidently formed on those fragments in a supercooled (-20 C) cloud chamber. It has been reported that charge generation from ocean volcanic eruptions is due to contact of molten lava with sea water. This seems to be insufficient to explain the observed rapid and intense lightning activities over Mount St. Helens eruptions. Therefore, a hypothesis is presented here that highly electrically charged fine solid fragments are ejected by bursting of gas bubbles from the surface of a crystallizing molten magma particles.

  12. Democracy and Schooling in California: The Legacy of Helen Heffernan and Corinne Seeds. Historical Studies in Education

    ERIC Educational Resources Information Center

    Weiler, Kathleen

    2011-01-01

    Helen Heffernan and Corinne Seeds were nationally recognized as leaders of the progressive education movement and were key figures in what was probably the most concerted attempt to put the ideals of progressive education into practice in a state-wide system of public education in the United States. This book examines the struggle over public…

  13. Towards a Transactional View of Rhetorical and Feminist Theory: Rereading Helen Cixous's "The Laugh of the Medusa."

    ERIC Educational Resources Information Center

    Biesecker, Barbara A.

    1992-01-01

    Argues that by rereading Helene Cixous's "The Laugh of Medusa" as a rhetoric--that is, an essay which posits what can and must be done by women if they are to intervene effectively in the public sphere through written or oral discourse--both rhetorical and feminist theory and criticism are enriched. (SR)

  14. Impossible Practice and Theories of the Impossible: A Response to Helene Illeris's "Potentials of Togetherness"

    ERIC Educational Resources Information Center

    Kallio-Tavin, Mira

    2014-01-01

    In a recent commentary in "Studies in Art Education," Helene Illeris (2013) discussed the idea of "performative experimental communities" via a critique of visual culture pedagogy and the romanticism of community-oriented art education in Nordic countries. Illeris underpinned her arguments with Jean-Luc Nancy's (1997)…

  15. An investigation of pre-eruptive deformation for the 2004 eruption of Mount St. Helens using persistent scatterer interferometry

    NASA Astrophysics Data System (ADS)

    Welch, M.; Schmidt, D. A.

    2014-12-01

    The volcanoes of the Cascade Range pose a legitimate threat to people living in the Pacific Northwest. Mt St Helens, which erupted in 2004 as a part of a dome building event, is a notable example of this danger. Deformation and seismicity are known indicators of volcanic activity and can provide warning of an imminent eruption. In the weeks leading up to the 2004 eruption, a shallow earthquake swarm was detected under St. Helens, suggesting ongoing deformation with its source beneath the edifice. A campaign GPS survey conducted in 2000 found no evidence of deformation. The sole continuous GPS station that was operational prior to the eruption (located ~9 km away from the crater) began moving only with the onset of the earthquake swarm. Because of the lack of ground based geodetic instruments in the near-field of Mt St Helens at the time of the 2004 eruption, it is unknown whether pre-eruptive deformation occurred on the edifice or solely within crater. InSAR is the only method available to conclusively determine whether the 2004 eruption was preceded by deformation of the edifice. Previous work explored this question using standard 2-pass interferometry, but the results were inconclusive. The main obstacle to implementing InSAR methods in the Cascades region is phase decorrelation due to the presence of both dense forest and snow for most of the year. We revisit the available InSAR data for St. Helens by experimenting with the application of the Persistent Scatterers and Distributed Scatterers processing techniques in order to overcome the decorrelation problem. By using these techniques on the question of Mt St Helens pre-eruptive deformation, we will demonstrate the viability of their application to the entire Northwest region as a low cost, low maintenance, monitoring tool.

  16. Solitary Waves, Magma Migration and Dome Building Eruptions at Mt. St. Helens, Washington

    NASA Astrophysics Data System (ADS)

    Ryan, M. P.; Stanley, B.; Plasker, M.

    2007-12-01

    Solitary waves have first-order attributes that include shape and volume conserving packets of fluid that migrate with characteristic wavelengths, amplitudes, wave numbers, and pulse durations. To ascend through dike-like, magma-filled fractures or sub-circular conduits, the solitary wave pulse duration is directly proportional to the conduit wall region viscosity and inversely proportional to the density contrast that drives the flow. Solitary waves are produced by the collapse of conduit wall rocks following the passage of a magma batch. The 1980-current eruptions at Mt. St. Helens display a variable time-series in their erupted volumes, as well as lava dome \\(or spine\\) heights / volumes and vent flow rates. Inter-eruption repose periods, however, have often shown broad regularity over extended periods. The rhythmic 'beat' of eruptive episodes within a long-lived series and their roughly regular repose periods arises directly from the solitary wave migration mechanism. Composite domes are suggested to be the products of solitary wave incremental additions of dacite, as in the 1980-1983 composite dome resulting from at least 9 such solitary wave-controlled additions. The 18 May 1980 dacite cryptodome may now be interpreted as a composite of several solitary wave-based intrusions leading to the climatic eruption volume. Domes may be either solitary or composite but are built up of one or several batches of evolving magma that ascend individually from the 8 to 1 km depth storage reservoir as solitary waves. Analytical calculations of wave speed, wave length, batch volume, parcel shapes and repose periods reveal the dependence on material properties appropriate for Mt. St. Helens intrusions and dome-building eruptions. Predicted solitary wave volumes and flow rates are in good agreement with observed values for dacitic dome and spine-building eruptions from 1980-1986 and from 2004-2007. Conduit dimensions are inferred to vary over the range R=2 to R=20 m. Magma

  17. Gas emissions and the eruptions of Mount St. Helens through 1982

    SciTech Connect

    Casadevall, T.; Rose, W.; Gerlach, T.; Greenland, L.P.; Ewert, J.; Wunderman, R.; Symonds, R.

    1983-09-30

    The monitoring of gas emissions from Mount St. Helens includes daily airborne measurements of sulfur dioxide in the volcanic plume and monthly sampling of gases from crater fumaroles. The composition of the fumarolic gases has changed slightly since 1980: the water content increased from 90 to 98 percent, and the carbon dioxide concentrations decreased from about 10 to 1 percent. The emission rates of sulfur dioxide and carbon dioxide were at their peak during July and August 1980, decreased rapidly in late 1980, and have remained low and decreased slightly through 1981 and 1982. These patterns suggest steady outgassing of a single batch of magma has been added since mid-1980. The gas data were useful in predicting eruptions in August 1980 and June 1981.

  18. Seismic precursors to the mount st. Helens eruptions in 1981 and 1982.

    PubMed

    Malone, S D; Boyko, C; Weaver, C S

    1983-09-30

    Six categories of seismic events are recognized on the seismograms from stations in the vicinity of Mount St. Helens. Two types of high-frequency earthquakes occur near the volcano and under the volcano at depths of more than 4 kilometers. Medium- and low-frequency earthquakes occur at shallow depths (less than 3 kilometers) within the volcano and increase in number and size before eruptions. Temporal changes in the energy release of the low-frequency earthquakes have been used in predicting all the eruptions since October 1980. During and after eruptions, two types of low-frequency emergent surface events occur, including rockfalls and steam or gas bursts from the lava dome. PMID:17759007

  19. Dynamics of seismogenic volcanic extrusion at Mount St Helens in 2004-05.

    PubMed

    Iverson, Richard M; Dzurisin, Daniel; Gardner, Cynthia A; Gerlach, Terrence M; LaHusen, Richard G; Lisowski, Michael; Major, Jon J; Malone, Stephen D; Messerich, James A; Moran, Seth C; Pallister, John S; Qamar, Anthony I; Schilling, Steven P; Vallance, James W

    2006-11-23

    The 2004-05 eruption of Mount St Helens exhibited sustained, near-equilibrium behaviour characterized by relatively steady extrusion of a solid dacite plug and nearly periodic shallow earthquakes. Here we present a diverse data set to support our hypothesis that these earthquakes resulted from stick-slip motion along the margins of the plug as it was forced incrementally upwards by ascending, solidifying, gas-poor magma. We formalize this hypothesis with a dynamical model that reveals a strong analogy between behaviour of the magma-plug system and that of a variably damped oscillator. Modelled stick-slip oscillations have properties that help constrain the balance of forces governing the earthquakes and eruption, and they imply that magma pressure never deviated much from the steady equilibrium pressure. We infer that the volcano was probably poised in a near-eruptive equilibrium state long before the onset of the 2004-05 eruption. PMID:17122849

  20. The role of mycorrhizal fungi and microsites in primary succession on Mount St. Helens.

    PubMed

    Titus, J; Del Moral, R

    1998-03-01

    This study was designed to examine the role of vesicular-arbuscular mycorrhizae (VAM) and microsites on the growth of pioneer species. Flat, rill, near-rock, and dead lupine microsites were created in plots in barren areas of the Pumice Plain of Mount St. Helens. VAM propagules were added to the soil in half of the plots. Six pioneer species were planted into both VAM and non-VAM inoculated microsites. Plants in dead lupine microsites were greater in biomass than those in flat, rill, and near-rock microsites. Significant effects of VAM on plant biomass did not occur. Microsites continue to be important to plant colonization on the Pumice Plain, but VAM do not yet appear to play an important role. This may be due to limited nutrient availability and the facultatively mycotrophic nature of the colonizing plant species. It is unlikely that VAM play an important role in successional processes in newly emplaced nutrient-poor surfaces. PMID:21684921

  1. Intrusive and extrusive growth of the Mount St Helens lava dome

    NASA Technical Reports Server (NTRS)

    Fink, Jonathan H.; Malin, Michael C.; Anderson, Steven W.

    1990-01-01

    High-resolution, digital topographic maps of the Mount St. Helens dome derived from aerial photographs are used here to make a quantitative assessment of the partitioning of magma into endogenous intrusion and exogenous lobes. The endogenous growth is found to be predictable, which shows that the cooling dome controls its own development independently of such deep-seated factors as magma overpressure and extrusion rate. The observed regular decrease in exogenous growth rate also allows volume prediction. Knowledge of the volume can be used to determine when an ongoing eruptive event should end. Finally, the observed transition from predominantly exogenous to predominantly endogenous growth reflects the increase in crust thickness, which in turn seems to depend on long repose periods rather than some fundamental change in the character of the dome.

  2. Monitoring the 1980-1982 eruptions of mount st. Helens: compositions and abundances of glass.

    PubMed

    Melson, W G

    1983-09-30

    The Mount St. Helens eruptive sequence of 1980 through 1982 reflects the tapping of successively less water-rich, more highly crystallized, and more viscous, highly phyric dacitic magmas. These changes reflect both syn- and preeruption processes. The decreasing water content points to a continued decline in the volume and intensity of explosive pyroclastic activity. This decreasing water content appears to be composed of a long-term trend established during a long period of repose (about 130 years) imposed on short-term trends established during short periods (about 7 to 100 days) of repose between eruptions in the present eruptive cycle. The last two eruptive cycles of this volcano, the T (A.D. 1800) and W cycles (about A. D. 1500), exhibited similar trends. These changes are inferred from a combination of petrographic, bulk chemical, and electron- and ion-microprobe analyses of matrix and melt-inclusion glasses. PMID:17759012

  3. Mount St. Helens dust veil observed at Boulder, Colorado by optical techniques

    NASA Technical Reports Server (NTRS)

    Lerfald, G.

    1982-01-01

    Following the May 18, 1980, eruption of Mount St. Helens, photometric and photograhic observations were taken at Boulder, Colorado, to record the optical effects of volcanic dust atmospherically transported to this area. The instruments used included a narrow-beamwidth solar photometer which recorded solar irradiance in eight narrow-bandwidth channels in the wavelength range 0.3 to 1.1 microns, a solar aureole photometer, and two time-lapse camera systems. The eight-channel solar photometer data have been analyzed to obtain the wavelength dependence of optical thickness. At the longer wavelengths, on May 20, 1980, the optical thickness was as much as nine times that expected from a 'clean atmosphere' model. During the first several days following the eruption, the dust veil sometimes exhibited sufficient spatial structure that its motion can be seen on the time-lapse films. The results of analysis to date are presented and the plans for additional analysis are outlined.

  4. Deep earthquakes beneath mount st. Helens: evidence for magmatic gas transport?

    PubMed

    Weaver, C S; Zollweg, J E; Malone, S D

    1983-09-30

    Small-magnitude earthquakes began beneath Mount St. Helens 40 days before the eruption of 20 March 1982. Unlike earlier preeruption seismicity for this volcano, which had been limited to shallow events (less than 3 kilometers), many of these earthquakes were deep (between 5 and 11 kilometers). The location of these preeruptive events at such depth indicates that a larger volume of the volcanic system was affected prior to the 20 March eruption than prior to any of the earlier dome-building eruptions. The depth-time relation between the deep earthquakes and the explosive onset of the eruption is compatible with the upward migration of magmatic gas released from a separate deep reservoir. PMID:17759013

  5. Petrologic monitoring of 1981 and 1982 eruptive products from mount st. Helens.

    PubMed

    Cashman, K V; Taggart, J E

    1983-09-30

    New material from the dacite lava dome of Mount St. Helens, collected soon after the start of each successive extrusion, is subjected to rapid chemical and petrologic analysis. The crystallinity of the dacite lava produced in 1981 and 1982 is 38 to 42 percent, about 10 percent higher than for products of the explosive 1980 eruptions. This increase in crystallinity accompanies a decrease in the ratio of hornblende to hornblende plus orthopyroxene, which suggests that the volatile-rich, crystal-poor material explosively erupted in 1980 came from the top of a zoned magma chamber and that a lower, volatile-poor and crystal-rich region is now being tapped. The major-element chemistry of the dacite lava has remained essentially constant (62 to 63 percent silica) since August 1980, ending a trend of decreasing silica seen in the products of the explosive eruptions of May through August 1980. PMID:17759011

  6. Gas emissions and the eruptions of mount st. Helens through 1982.

    PubMed

    Casadevall, T; Rose, W; Gerlach, T; Greenland, L P; Ewert, J; Wunderman, R; Symonds, R

    1983-09-30

    The monitoring of gas emissions from Mount St. Helens includes daily airborne measurements of sulfur dioxide in the volcanic plume and monthly sampling of gases from crater fumaroles. The composition of the fumarolic gases has changed slightly since 1980: the water content increased from 90 to 98 percent, and the carbon dioxide concentrations decreased from about 10 to 1 percent. The emission rates of sulfur dioxide and carbon dioxide were at their peak during July and August 1980, decreased rapidly in late 1980, and have remained low and decreased slightly through 1981 and 1982. These patterns suggest steady outgassing of a single batch of magma (with a volume of not less than 0.3 cubic kilometer) to which no significant new magma has been added since mid-1980. The gas data were useful in predicting eruptions in August 1980 and June 1981. PMID:17759010

  7. Hydrogen-isotope evidence for extrusion mechanisms of the Mount St Helens lava dome

    NASA Technical Reports Server (NTRS)

    Anderson, Steven W.; Fink, Jonathan H.

    1989-01-01

    Hydrogen isotope analyses were used to determine water content and deuterium content for 18 samples of the Mount St Helens dome dacite in an attempt to identify the triggering mechanisms for periodic dome-building eruptions of lava. These isotope data, the first ever collected from an active lava dome, suggest a steady-state process of magma evolution combining crystallization-induced volatile production in the chamber with three different degassing mechanisms: closed-system volatile loss in the magma chamber, open-system volatile release during ascent, and kinetically controlled degassing upon eruption at the surface. The data suggest the future dome-building eruptions may require a new influx of volatile-rich magma into the chamber.

  8. Gaseous constituents in the plume from eruptions of Mount St. Helens

    NASA Technical Reports Server (NTRS)

    Inn, E. C. Y.; Vedder, J. F.; Condon, E. P.; Ohara, D.

    1981-01-01

    Measurements in the stratosphere of gaseous constituents in the plume of Mount St. Helens were obtained during five flights of the NASA U-2 aircraft between 19 May and 17 June 1980. Mixing ratios from gas chromatographic measurements on samples acquired about 24 hours after the initial eruption show considerable enhancement over nonvolcanic concentrations for sulfur dioxide (more than 1000 times), methyl chloride (about 10 times), and carbon disulfide (more than 3 times). The mixing ratio of carbonyl sulfide was comparable to nonvolcanic mixing ratios although 3 days later it was enhanced two to three times. Ion chromatography measurements on water-soluble constituents are also reported. Very large concentrations of chloride, nitrate, and sulfate ions were measured, implying large mixing ratios for the water-soluble gaseous constituents from which the anions are derived. Measurements of radon-222 present in the plume are also reported.

  9. Seismic precursors to the Mount St. Helens: Eruptions in 1981 and 1982

    USGS Publications Warehouse

    Malone, S.D.; Boyko, C.; Weaver, C.S.

    1983-01-01

    Six categories of seismic events are recognized on the seismograms from stations in the vicinity of Mount St. Helens. Two types of high-frequency earthquakes occur near the volcano and under the volcano at depths of more than 4 kilometers. Medium- and low-frequency earthquakes occur at shallow depths (less than 3 kilometers) within the volcano and increase in number and size before eruptions. Temporal changes in the energy release of the low-frequency earthquakes have been used in predicting all the eruptions since October 1980. During and after eruptions, two types of low-frequency emergent surface events occur, including rockfalls and steam or gas bursts from the lava dome.

  10. Deep earthquakes beneath Mount St. Helens: Evidence for magmatic gas transport?

    USGS Publications Warehouse

    Weaver, C.S.; Zollweg, J.E.; Malone, S.D.

    1983-01-01

    Small-magnitude earthquakes began beneath Mount St. Helens 40 days before the eruption of 20 March 1982. Unlike earlier preeruption seismicity for this volcano, which had been limited to shallow events (less than 3 kilometers), many of these earthquakes were deep (between 5 and 11 kilometers). The location of these preeruptive events at such depth indicates that a larger volume of the volcanic system was affected prior to the 20 March eruption than prior to any of the earlier dome-building eruptions. The depth-time relation between the deep earthquakes and the explosive onset of the eruption is compatible with the upward migration of magmatic gas released from a separate deep reservoir.

  11. Forward scattering and backscattering of solar radiation by the stratospheric limb after Mount St. Helens eruption

    NASA Technical Reports Server (NTRS)

    Ackerman, M.; Lippens, C.

    1982-01-01

    Stratospheric limb radiance profiles versus altitude of closest approach of the line of sight to the Earth's surface have been measured before and after the Mount St. Helens eruptions by means of photographs taken from a Sun-oriented balloon gondola floating above 35 km altitude over France. Preliminary data were reported for flights in October 1979 and in May and June 1980. The radiance integrated along the line of sight as in-situ radiance (R) can be derived taking into account absorption by ozone and air. The onion peeling inversion method was used to derive the vertical radiance (R) profiles respectively. The values of R were determined in the solar azimuth. The solar elevation angles are chosen larger for the backscattering observation than for the forward scattering observation to deal with as similar illumination conditions as possible despite the Earth's sphericity.

  12. Evaluation of heat flow and its geological implications on Mt. St. Helens

    SciTech Connect

    Grady, T.; Adams, E.; Brown, R.L.; Sato, A.

    1982-04-01

    A study to determine the heat flux pattern in the vicinity of Mt. St. Helens was undertaken as part of a program to evaluate the effects of the eruption on future snowpack conditions in the area. Subsurface temperature and low energy refraction seismic studies were made during the early spring in 1981 to determine both the heat flux in the area of pyroclastic deposition and its potential source. In addition, samples were collected for later laboratory determination of thermal conductivity and diffusivity. Results indicate that the heat flow values in the area of pyroclastic deposition are as large as forty times greater than the heat flow values measured on Mt. Adams and Mt. Hood during the same period. The highest heat flow values appear to coincide with a pumice flow unit on the north side of the mountain.. Comparison with work done on the eruption of Mt. Komagatake indicates that the large heat flow values continue for several years.

  13. Thermal property measurements in a fresh pumice flow at Mt. St. Helens

    SciTech Connect

    Hardee, H.C.

    1981-03-01

    A thermal penetrator that was air dropped into a freshly emplaced pumice flow at Mt. St. Helens yielded information on the in-situ thermal properties of the pumice. The in-situ conductivity-density-specific heat product at a depth of 60 cm was found to be 7.24 x 10/sup -5/ cal/sup 2/cm//sup 4/ s- /sup 0/C/sup 2/ at an average pumice temperature of 200 /sup 0/C. Using this data, values for the average in-situ thermal conductivity (2.9 x 10/sup -4/ cal/cm-s-/sup 0/C) and thermal diffusivity (1.2 x 10/sup -3/ cm/sup 2//s) were estimated. These thermal properties are of use in studies of pumice cooling and in the interpretation of infrared remote sensing data.

  14. In the path of destruction - eyewitness chronicles of Mount St. Helens

    USGS Publications Warehouse

    Waitt, Richard B.

    2015-01-01

    “The air had no oxygen, like being trapped underwater…I was being cremated, the pain unbearable.”-- Jim Scymanky“I was on my knees, my back to the hot wind. It blew me along, lifting my rear so I was up on my hands…It was hot but I didn’t feel burned—until I felt my ears curl.”—Mike HubbardA napping volcano blinked awake in March 1980. Two months later, the mountain roared. Author Richard Waitt was one of the first to arrive following the mountain’s early rumblings. A geologist with intimate knowledge of Mount St. Helens, Waitt delivers a detailed and accurate chronicle of events. The eruption story unfolds through unforgettable, riveting narratives—the heart of a masterful chronology that also delivers engrossing science, history, and journalism.

  15. Gas emissions and the eruptions of Mount St. Helens through 1982

    USGS Publications Warehouse

    Casadevall, T.; Rose, W.; Gerlach, T.; Greenland, L.P.; Ewert, J.; Wunderman, R.; Symonds, R.

    1983-01-01

    The monitoring of gas emissions from Mount St. Helens includes daily airborne measurements of sulfur dioxide in the volcanic plume and monthly sampling of gases from crater fumaroles. The composition of the fumarolic gases has changed slightly since 1980: the water content increased from 90 to 98 percent, and the carbon dioxide concentrations decreased from about 10 to 1 percent. The emission rates of sulfur dioxide and carbon dioxide were at their peak during July and August 1980, decreased rapidly in late 1980, and have remained low and decreased slightly through 1981 and 1982. These patterns suggest steady outgassing of a single batch of magma (with a volume of not less than 0.3 cubic kilometer) to which no significant new magma has been added since mid-1980. The gas data were useful in predicting eruptions in August 1980 and June 1981.

  16. Dynamics of seismogenic volcanic extrusion at Mount St Helens in 2004-05

    USGS Publications Warehouse

    Iverson, R.M.; Dzurisin, D.; Gardner, C.A.; Gerlach, T.M.; LaHusen, R.G.; Lisowski, M.; Major, J.J.; Malone, S.D.; Messerich, J.A.; Moran, S.C.; Pallister, J.S.; Qamar, A.I.; Schilling, S.P.; Vallance, J.W.

    2006-01-01

    The 2004-05 eruption of Mount St Helens exhibited sustained, near-equilibrium behaviour characterized by relatively steady extrusion of a solid dacite plug and nearly periodic shallow earthquakes. Here we present a diverse data set to support our hypothesis that these earthquakes resulted from stick-slip motion along the margins of the plug as it was forced incrementally upwards by ascending, solidifying, gas-poor magma. We formalize this hypothesis with a dynamical model that reveals a strong analogy between behaviour of the magma-plug system and that of a variably damped oscillator. Modelled stick-slip oscillations have properties that help constrain the balance of forces governing the earthquakes and eruption, and they imply that magma pressure never deviated much from the steady equilibrium pressure. We infer that the volcano was probably poised in a near-eruptive equilibrium state long before the onset of the 2004-05 eruption. ??2006 Nature Publishing Group.

  17. Seismic and acoustic recordings of an unusually large rockfall at Mount St. Helens, Washington

    USGS Publications Warehouse

    Moran, S.C.; Matoza, R.S.; Garces, M.A.; Hedlin, M.A.H.; Bowers, D.; Scott, W.E.; Sherrod, D.R.; Vallance, J.W.

    2008-01-01

    On 29 May 2006 a large rockfall off the Mount St. Helens lava dome produced an atmospheric plume that was reported by airplane pilots to have risen to 6,000 m above sea level and interpreted to be a result of an explosive event. However, subsequent field reconnaissance found no evidence of a ballistic field, indicating that there was no explosive component. The rockfall produced complex seismic and infrasonic signals, with the latter recorded at sites 0.6 and 13.4 km from the source. An unusual, very long-period (50 s) infrasonic signal was recorded, a signal we model as the result of air displacement. Two high-frequency infrasonic signals are inferred to result from the initial contact of a rock slab with the ground and from interaction of displaced air with a depression at the base of the active lava dome. Copyright 2008 by the American Geophysical Union.

  18. Magmatic model for the Mount St. Helens blast of May 18, 1980

    SciTech Connect

    Eichelberger, J.C.; Hayes, D.B.

    1982-09-10

    Analytical and numerical solutions to the hydrodynamic equations of motion, constrained by physical properties of juvenile ejecta in the Mount St. Helens blast deposit, were used to investigate magmatic conditions required to produce the initial devastating blast phase of the eruption of May 18, 1980. Evidence that the blast was magmatic includes equivalence in volume of juvenile blast ejecta to preeruption inflation of the cone, substantial vesicularity of this ejecta, and continued vesiculation of large juvenile clasts after eruption. Observed or inferred ejecta velocities of 100 to 250 m/s are shown to require 0.2 to 0.7 wt% water vapor preexisting in magma unloaded by a landslide 200 to 900 m thick. These conditions imply total magmatic water contents of 0.7 to 1.7 wt%, respectively. Such low required water content suggests that volcanic blasts may be regarded as a normal consequence of magma intrusion into an unstable edifice.

  19. Health-hazard-evaluation report MHETA 89-362-2027, Helen Mining Company, Homer City, Pennsylvania

    SciTech Connect

    Ferguson, R.P.

    1990-03-01

    In response to a request from the United Mine Workers of America, an investigation was made of possible hazardous working conditions at the Helen Mining Company, Homer City, Pennsylvania. One of the tipple operators had complained of headaches, dizziness and skin rashes from working with a mixture of solvents used in the float/sink test operation. The solvents included perchloroethylene and dibromomethane. A week prior to receiving the request, the use of dibromomethane had been discontinued. Consequently, on the visit to the site, no traces of dibromomethane were found. After engineering controls were installed, only one of seven personal breathing zone samples detected any perchloroethylene, and that sample was 0.12 parts per million, at the limit of detection. The author concludes that a hazard from perchloroethylene did not exist at the time of the evaluation. The author recommends replacing the rubber/cloth type glove being used with either a Teflon or Viton glove, and enclosing the work table.

  20. Anthropology in a postcolonial colony: Helen I. Safa's contribution to Puerto Rican ethnography.

    PubMed

    Duany, Jorge

    2010-01-01

    This article assesses Helen I. Safa's legacy to anthropological thought in Puerto Rico. The first part of the article locates Safa's research on the Island within a long tradition of fieldwork by U.S. scholars since the early twentieth century. More recent research, conducted mostly by Puerto Rican women anthropologists and other social scientists, has expanded upon Safa's insights on gender and work. The second part of the essay analyzes Safa's major empirical work, The Urban Poor of Puerto Rico: A Study in Development and Inequality. Above all, this book helped overcome the theoretical impasse over the culture of poverty that characterized much of urban anthropology during the 1960s and 1970s. The article concludes with an appraisal of the relevance of Safa's work for the ethnography of contemporary Puerto Rico. PMID:22073441

  1. Was the 18 May 1980 lateral blast at Mt St Helens the product of two explosions?

    USGS Publications Warehouse

    Hoblitt, R.P.

    2000-01-01

    The 18 May 1980 lateral blast at Mt St Helens has been interpreted as the product of a single explosion by some stratigraphers and as two closely spaced explosions by others. The stratigraphic evidence that bears on this question is inconclusive; strata change dramatically over short distances and this complexity provides wide latitude for interpretation. Some independent non-stratigraphic evidence, however, suggests that the blast was the product of two explosions or clusters of explosions. The independent evidence comes from eyewitness accounts and photographs, from satellite sensors, and from seismic records. This paper reviews the pertinent evidence, offers a new interpretation, and concludes that the blast was indeed the product of two explosions or clusters of explosions.

  2. Target diagnostics for commissioning the AWE HELEN Laser Facility 100 TW chirped pulse amplification beam

    NASA Astrophysics Data System (ADS)

    Eagleton, R. T.; Clark, E. L.; Davies, H. M.; Edwards, R. D.; Gales, S.; Girling, M. T.; Hoarty, D. J.; Hopps, N. W.; James, S. F.; Kopec, M. F.; Nolan, J. R.; Ryder, K.

    2006-10-01

    The capability of the HELEN laser at the Atomic Weapons Establishment Aldermaston has been enhanced by the addition of a short-pulse laser beam to augment the twin opposing nanosecond time scale beams. The short-pulse beam utilizes the chirped pulse amplification (CPA) technique and is capable of delivering up to 60J on target in a 500fs pulse, around 100TW, at the fundamental laser wavelength of 1.054μm. During the commissioning phase a number of diagnostic systems have been fielded, these include: x-ray pinhole imaging of the laser heated spot, charged particle time of flight, thermoluminescent dosimeter array, calibrated radiochromic film, and CR39 nuclear track detector. These diagnostic systems have been used to verify the performance of the CPA beam to achieve a focused intensity of around 1019Wcm-2 and to underwrite the facility radiological safety system.

  3. Chronology and pyroclastic stratigraphy of the May 18, 1980, eruption of Mount St. Helens, Washington

    NASA Technical Reports Server (NTRS)

    Criswell, C. William

    1987-01-01

    The eruption of Mount St. Helens on May 18, 1980 can be subdivided into six phases: the paroxysmal phase I, the early Plinian phase II, the early ash flow phase III, the climactic phase IV, the late ash flow phase V, and phase VI, the activity of which consisted of a low-energy ash plume. These phases are correlated with stratigraphic subunits of ash-fall tephra and pyroclastic flow deposits. Sustained vertical discharge of phase II produced evolved dacite with high S/Cl ratios. Ash flow activity of phase III is attributed to decreases in gas content, indicated by reduced S/Cl ratios and increased clast density of the less evolved gray pumice. Climactic events are attributed to vent clearing and exhaustion of the evolved dacite.

  4. Monitoring vegetation recovery patterns on Mount St. Helens using thermal infrared multispectral data

    NASA Technical Reports Server (NTRS)

    Langran, K. J.

    1985-01-01

    The eruptions of Mount St. Helens created new surfaces by stripping and implacing large volumes of eroded material and depositing tephra in the blast area and on the flanks of the mountain. Areas of major disturbance are those in the blast zone that were subject to debris avalanche, pyroclastic flows, mudflows, and blowdown and scorched timber; and those outside the blast zone that received extensive tephra deposits. These zones represent a spectrum of disturbance types and intensities that can be indexed by temperature, impact force, and depth of subsequent deposition. This paper describes an application of NASA's Thermal Infrared Multispectral Scanner (TIMS) in monitoring vegetation recovery patterns in disturbed areas. Preliminary study results indicate a significant correlation between measured effective radiant temperature and vegetated/nonvegetated areas, percent vegetation cover, and vegetation type.

  5. Trophic Interactions during Primary Succession: Herbivores Slow a Plant Reinvasion at Mount St. Helens.

    PubMed

    Fagan; Bishop

    2000-02-01

    Lupines (Lupinus lepidus var. lobbii), the earliest plant colonists of primary successional habitats at Mount St. Helens, were expected to strongly affect successional trajectories through facilitative effects. However, their effects remain localized because initially high rates of reinvasive spread were short lived, despite widespread habitat availability. We experimentally tested whether insect herbivores, by reducing plant growth and fecundity at the edge of the expanding lupine population, could curtail the rate of reinvasion and whether those herbivores had comparable impacts in the older, more successionally advanced core region. We found that removing insect herbivores increased both the areal growth of individual lupine plants and the production of new plants in the edge region, thereby accelerating the lupine's intrinsic rate of increase at the front of the lupine reinvasion. We found no such impacts of herbivory in the core region, where low plant quality or a complex of recently arrived natural enemies may hold herbivores in check. In the context of invasion theory, herbivore-mediated decreases in lupine population growth rate in the edge region translate into decreased rates of lupine spread, which we quantify here using diffusion models. In the Mount St. Helens system, decreased rate of lupine reinvasion will result in reductions in rates of soil formation, nitrogen input, and entrapment of seeds and detritus that are likely to postpone or alter trajectories of primary succession. If the type of spatial subtleties in herbivore effects we found here are common, with herbivory focused on the edge of an expanding plant population and suppressed or ineffective in the larger, denser central region (where the plants might be more readily noticed and studied), then insect herbivores may have stronger impacts on the dynamics of primary succession and plant invasions than previously recognized. PMID:10686163

  6. A continuous record of intereruption velocity change at Mount St. Helens from coda wave interferometry

    NASA Astrophysics Data System (ADS)

    Hotovec-Ellis, A. J.; Gomberg, J.; Vidale, J. E.; Creager, K. C.

    2014-03-01

    In September 2004, Mount St. Helens volcano erupted after nearly 18 years of quiescence. However, it is unclear from the limited geophysical observations when or if the magma chamber replenished following the 1980-1986 eruptions in the years before the 2004-2008 extrusive eruption. We use coda wave interferometry with repeating earthquakes to measure small changes in the velocity structure of Mount St. Helens volcano that might indicate magmatic intrusion. By combining observations of relative velocity changes from many closely located earthquake sources, we solve for a continuous function of velocity changes with time. We find that seasonal effects dominate the relative velocity changes. Seismicity rates and repeating earthquake occurrence also vary seasonally; therefore, velocity changes and seismicity are likely modulated by snow loading, fluid saturation, and/or changes in groundwater level. We estimate hydrologic effects impart stress changes on the order of tens of kilopascals within the upper 4 km, resulting in annual velocity variations of 0.5 to 1%. The largest nonseasonal change is a decrease in velocity at the time of the deep Mw = 6.8 Nisqually earthquake. We find no systematic velocity changes during the most likely times of intrusions, consistent with a lack of observable surface deformation. We conclude that if replenishing intrusions occurred, they did not alter seismic velocities where this technique is sensitive due to either their small size or the finite compressibility of the magma chamber. We interpret the observed velocity changes and shallow seasonal seismicity as a response to small stress changes in a shallow, pressurized system.

  7. A continuous record of intereruption velocity change at Mount St. Helens from coda wave interferometry

    USGS Publications Warehouse

    Hotovec-Ellis, Alicia J.; Gomberg, Joan S.; Vidale, John; Creager, Ken C.

    2014-01-01

    In September 2004, Mount St. Helens volcano erupted after nearly 18 years of quiescence. However, it is unclear from the limited geophysical observations when or if the magma chamber replenished following the 1980–1986 eruptions in the years before the 2004–2008 extrusive eruption. We use coda wave interferometry with repeating earthquakes to measure small changes in the velocity structure of Mount St. Helens volcano that might indicate magmatic intrusion. By combining observations of relative velocity changes from many closely located earthquake sources, we solve for a continuous function of velocity changes with time. We find that seasonal effects dominate the relative velocity changes. Seismicity rates and repeating earthquake occurrence also vary seasonally; therefore, velocity changes and seismicity are likely modulated by snow loading, fluid saturation, and/or changes in groundwater level. We estimate hydrologic effects impart stress changes on the order of tens of kilopascals within the upper 4 km, resulting in annual velocity variations of 0.5 to 1%. The largest nonseasonal change is a decrease in velocity at the time of the deep Mw = 6.8 Nisqually earthquake. We find no systematic velocity changes during the most likely times of intrusions, consistent with a lack of observable surface deformation. We conclude that if replenishing intrusions occurred, they did not alter seismic velocities where this technique is sensitive due to either their small size or the finite compressibility of the magma chamber. We interpret the observed velocity changes and shallow seasonal seismicity as a response to small stress changes in a shallow, pressurized system.

  8. Mass Intrusion at Mount St. Helens (WA) From Temporal Gravity Variations

    NASA Astrophysics Data System (ADS)

    Battaglia, M.; Lisowski, M.; Dzurisin, D.; Poland, M. P.; Schilling, S. P.; Diefenbach, A. K.; Wynn, J.

    2015-12-01

    Repeated high-precision gravity measurements made at Mount St. Helens (WA) have revealed systematic temporal variations in the gravity field several years after the end of the 2004-2008 dome-building eruption. Changes in gravity with respect to a stable reference station 36 km NW of the volcano were measured at 10 sites on the volcanic edifice and at 4 sites far afield (10 to 36 km) from the summit in August 2010, August 2012 and August 2014. After simulating and removing the gravity signal associated with changes in mass of the crater glacier, the local hydrothermal aquifer, and vertical deformation, the residual gravity field observed at sites near the volcano's summit significantly increased with respect to the stable reference site during 2010-2012 (maximum change 48 ± 15 mgal). No significant change was measured during 2012-2014. The pattern of gravity increase is radially symmetrical, with a half-width of about 2.5 km and a point of maximum change centered at the 2004-2008 lava dome. Forward modeling of residual gravity data using the same source geometry, depth, and location as that inferred from geodetic data (a spheroidal source centered 7.5 km beneath the 2004-2008 dome) indicates a mass increase rate of the order of 1011 kg/year. For a reasonable magma density (~2250 kg/m3), the volume rate of magma intrusion beneath the summit region inferred from gravity (~ 0.1 km3/yr) greatly exceeds the volume inferred from inversion of geodetic data (0.001 km3/yr between 2008-2011), suggesting that either magma compressibility or other processes are important aspects of magma storage at Mount St. Helens, or that the data argue for a different source.

  9. The effects of catastrophic ecosystem disturbance: the residual mammals at Mount St. Helens

    USGS Publications Warehouse

    Andersen, Douglas C.; MacMahon, James A.

    1985-01-01

    Individuals that survive the direct effects of community- or ecosystem-level disturbances, i.e., "residuals", can have major roles in determining the rate and pathway of subsequent secondary succession. The explosive eruption of the Mount St. Helens volcano on 19 May 1980 resulted in severe damage to a cast array of animal and plant populations (Edwards and Schwartz, 1981; MacMahon, 1982; Hayward et al., 1982). We apply the term "catastrophic" to this event because of its intensity and the large area (>600 km2) over which successional processes were initiated. We present here the results of surveys for mammals, particularly small mammals (excluding bats), conducted in the Mount St. Helens region during the 40 months following the eruption. Our purpose was to elucidate any patterns in species representation that might exist along a gradient of disturbance "intensity", and thus document which species could potentially influence early plant successional patterns there. We infer whether individuals captured were more likely to have been residuals (or their descendants), or immigrants from areas less affected by the eruption, from consideration of the time span between the eruption and the capture date, the trapping location, and life history data. We also make inferences concerning the animal-environment relationships that led to our survey results, and thereby address the question of the likelihood of other types of disturbance, either natural or anthropogenic, producing similar results. Data concerning survival of Thomomys talpoides, the northern pocket gopher, have been presented elsewhere (Andersen, 1982). Initial results from our studies of the relationships among residual small mammals and plant population dynamics are detailed in MacMahon and Warner (1984), Allen et al. (1984) and Andersen and MacMahon (in press).

  10. Attenuation and Scattering Tomography of the Deep Plumbing System of Mount St. Helens

    NASA Astrophysics Data System (ADS)

    De Siena, L.; Thomas, C.; Waite, G. P.; Moran, S. C.; Klemme, S.

    2014-12-01

    We present a combined 3D P-wave attenuation, 2D S-coda attenuation, and 3D S-coda scattering tomography model of fluid pathways, feeding systems, and sediments below Mount St. Helens (MSH) volcano between depths of 0 and 18 km. High-scattering and high-attenuation shallow anomalies are indicative of magma and fluid-rich zones within and below the volcanic edifice down to 6 km depth, where a high-scattering body outlines the top of a deeper aseismic velocity anomaly. Both the volcanic edifice and these structures induce a combination of strong scattering and attenuation on any seismic wave-field, particularly those recorded on the northern and eastern flanks of the volcanic cone. North of the cone, between depths of 0 and 10 km, a low-velocity, high-scattering, and high-attenuation north-south trending trough is attributed to thick piles of Tertiary marine sediments within the St. Helens Seismic Zone. A laterally-extended 3D scattering contrast at depths of 10 to 14 km is related to the boundary between upper and lower crust, and caused in our interpretation by the large scale interaction of the Siletz terrane with the Cascade arc crust. This contrast presents a low scattering, 4-6 km2 "hole" under the north-eastern flank of the volcano. We infer that this section represents the main path of magma ascent from depths greater than 6 km at MSH, with a small north-east shift in the lower plumbing system of the volcano. We conclude that combinations of different non-standard tomographic methods, and particularly the application of full-waveform tomography to highly heterogeneous media, represent the future of seismic volcano imaging.