Science.gov

Sample records for chan helen meng

  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. 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)

  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. 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…

  6. Replanting St. Helens

    SciTech Connect

    Holbrook, J.J.

    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 50,000 acres of devastated land which was located around the site of the eruption. It also discussed the natural recovery of this area and the reestablishment of ecosystems and rebuilding of habitats by the plants and animals.

  7. Mt. St. Helens

    NASA Image and Video Library

    2001-10-22

    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. 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. http://photojournal.jpl.nasa.gov/catalog/PIA11160

  8. 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.

  9. 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

  10. 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.

  11. Rebuilding Mount St. Helens

    USGS Publications Warehouse

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

    2006-01-01

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

  12. Coal and cremation at the Tschudi burn, Chan Chan, Northern Peru

    USGS Publications Warehouse

    Brooks, W.E.; Galvez, Mora C.; Jackson, J.C.; McGeehin, J.P.; Hood, D.G.

    2008-01-01

    Analyses of a 20-30 cm thick, completely combusted ash at the 25 ?? 70 m Tschudi burn at Chan Chan, northern Peru??, contain 52-55 wt% SiO2, 180-210 ppm zirconium and are consistent with coal ash. Soil geochemistry across the burn showed elevated calcium and phosphorus content, possible evidence for reported human cremation. A calcined, 5 g, 4.5 cm skull fragment recovered from the burn was confirmed as human by protein radioimmunoassay (pRIA). X-ray diffraction showed that the bone had been heated to 520??C. The burn took place c. ad 1312-1438 based on interpretation of a 14C date on carbonized plant tinder. ?? 2008 University of Oxford.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. VIEW OF PIEDMONT AVENUE BETWEEN CHANNING WAY AND DURANT AVENUE. ...

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

    VIEW OF PIEDMONT AVENUE BETWEEN CHANNING WAY AND DURANT AVENUE. 2325 PIEDMONT (MRS. F.W. FISH HOUSE DESIGNED BY CHARLES S. KAISER, 1910. SEEN FROM WEST SIDE OF PIEDMONT LOOKING NORTH. Photograph by Fredrica Drotos and Michael Kelly, July 9, 2006 - Piedmont Way & the Berkeley Property Tract, East of College Avenue between Dwight Way & U.C. Memorial Stadium, Berkeley, Alameda County, CA

  20. VIEW OF PIEDMONT AVENUE TRAFFIC CIRCLE AT INTERSECTION OF CHANNING ...

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

    VIEW OF PIEDMONT AVENUE TRAFFIC CIRCLE AT INTERSECTION OF CHANNING WAY. SEEN FROM NE CORNER LOOKING SW. Photograph by Fredrica Drotos and Michael Kelly, July 9, 2006 - Piedmont Way & the Berkeley Property Tract, East of College Avenue between Dwight Way & U.C. Memorial Stadium, Berkeley, Alameda County, CA

  1. VIEW OF PIEDMONT AVENUE TRAFFIC CIRCLE AT INTERSECTION OF CHANNING ...

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

    VIEW OF PIEDMONT AVENUE TRAFFIC CIRCLE AT INTERSECTION OF CHANNING WAY VIEW OF 2401 PIEDMONT, ALPHA EPSILON PHI HOUSE BY RATCLIFF & RATCLIFF, 1958. SEEN FROM NW CORNER LOOKING SE. Photograph by Brian Grogan, July 8, 2007 - Piedmont Way & the Berkeley Property Tract, East of College Avenue between Dwight Way & U.C. Memorial Stadium, Berkeley, Alameda County, CA

  2. DETAIL VIEW OF SIDEWALKS AND TREES ON CHANNING WAY AT ...

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

    DETAIL VIEW OF SIDEWALKS AND TREES ON CHANNING WAY AT INTERSECTION OF PIEDMONT AVENUE WITH 2395 PIEDMONT, SIGMA PI HOUSE BY FREDERICK H. REIMERS, 1928, LOOKING NW. Photograph by Fredrica Drotos and Michael Kelly, July 9, 2006 - Piedmont Way & the Berkeley Property Tract, East of College Avenue between Dwight Way & U.C. Memorial Stadium, Berkeley, Alameda County, CA

  3. VIEW OF PIEDMONT AVENUE TRAFFIC CIRCLE AT INTERSECTION OF CHANNING ...

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

    VIEW OF PIEDMONT AVENUE TRAFFIC CIRCLE AT INTERSECTION OF CHANNING WAY. SEEN FROM SW CORNER TOWARDS 2395 PIEDMONT, SIGMA PI HOUSE BY FREDERICK H. REIMERS, 1928. LOOKING NORTH. Photograph by Brian Grogan, July 8, 2007 - Piedmont Way & the Berkeley Property Tract, East of College Avenue between Dwight Way & U.C. Memorial Stadium, Berkeley, Alameda County, CA

  4. VIEW OF PIEDMONT AVENUE AT CHANNING WAY. NOTE LANDSCAPE FEATURES ...

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

    VIEW OF PIEDMONT AVENUE AT CHANNING WAY. NOTE LANDSCAPE FEATURES PRIOR TO RECONSTRUCTION AND NEW CURBING AS SEEN IN PHOTOGRAPH NO. CA-2-8. LOOKING NE. Photograph by Fredrica Drotos and Michael Kelly, July 9, 2006 - Piedmont Way & the Berkeley Property Tract, East of College Avenue between Dwight Way & U.C. Memorial Stadium, Berkeley, Alameda County, CA

  5. The Story behind the Catalyst: Channing Club Vs. the Board of Regents of TTU

    ERIC Educational Resources Information Center

    Duemer, Lee S.; Bankes, Paul; Boss, Jeffrey; Cochran, Amanda; McCrary, Jaci; Salazar, Dora

    2005-01-01

    The lawsuit Channing Club vs. The Board of Regents of Texas Tech University, 1970 has been used as a legal precedent in many student press censorship cases. A thorough understanding of Channing has become increasingly important since Hazelwood and other related decisions. Though Channing has been frequently cited in the literature, comparatively…

  6. The Story behind the Catalyst: Channing Club Vs. the Board of Regents of TTU

    ERIC Educational Resources Information Center

    Duemer, Lee S.; Bankes, Paul; Boss, Jeffrey; Cochran, Amanda; McCrary, Jaci; Salazar, Dora

    2005-01-01

    The lawsuit Channing Club vs. The Board of Regents of Texas Tech University, 1970 has been used as a legal precedent in many student press censorship cases. A thorough understanding of Channing has become increasingly important since Hazelwood and other related decisions. Though Channing has been frequently cited in the literature, comparatively…

  7. Restructuring Graduate Engineering Education: The M.Eng. Program at Cornell.

    ERIC Educational Resources Information Center

    Cady, K. Bingham; And Others

    1988-01-01

    Discusses the restructuring of the graduate program to accommodate emerging fields in engineering. Notes half of the graduate degrees Cornell grants each year are M.Eng. degrees. Offers 12 specialties: aerospace, agriculture, chemical, civil, electrical, mechanical and nuclear engineering; computer science, engineering physics; geological…

  8. Restructuring Graduate Engineering Education: The M.Eng. Program at Cornell.

    ERIC Educational Resources Information Center

    Cady, K. Bingham; And Others

    1988-01-01

    Discusses the restructuring of the graduate program to accommodate emerging fields in engineering. Notes half of the graduate degrees Cornell grants each year are M.Eng. degrees. Offers 12 specialties: aerospace, agriculture, chemical, civil, electrical, mechanical and nuclear engineering; computer science, engineering physics; geological…

  9. CHANS-Net: Opportunities for the bigger picture in hydrology

    NASA Astrophysics Data System (ADS)

    Nichols, S.

    2012-12-01

    CHANS-Net: International Network of Research on Coupled Human and Natural Systems is an NSF-funded effort that facilitates communication and collaboration among scholars from around the world who are interested in coupled human and natural systems (CHANS) (e.g., coupled human-environment systems, social-ecological systems, ecological-economic systems, population-environment systems) and who strive to find sustainable solutions that both benefit the environment and enable people to thrive. Reaching across research boundaries to study coupled human and natural systems has been documented to put genuine sustainability in reach. But the design also is more challenging as a researcher ventures into unfamiliar disciplines. The network is striving to build a supportive community of researchers to enhance collaboration and partnerships and offer examples of best practices. CHANS-Net researchers have found that seemingly unconnected issues, divorce and the environment for example, are interrelated and affect each other in ways that we are only just beginning to understand.

  10. CHANS-Net: Opportunities in the Bigger Picture

    NASA Astrophysics Data System (ADS)

    Depolo, J. M.

    2012-12-01

    CHANS-Net: International Network of Research on Coupled Human and Natural Systems is an NSF-funded effort that facilitates communication and collaboration among scholars from around the world who are interested in coupled human and natural systems (CHANS) (e.g., coupled human-environment systems, social-ecological systems, ecological-economic systems, population-environment systems) and who strive to find sustainable solutions that both benefit the environment and enable people to thrive. Reaching across research boundaries to study coupled human and natural systems has been documented to put genuine sustainability in reach. But the design also is more challenging as a researcher ventures into unfamiliar disciplines. The network is striving to build a supportive community of researchers to enhance collaboration and partnerships and offer examples of best practices. CHANS-Net researchers have found that seemingly unconnected issues, divorce and the environment for example, are interrelated and affect each other in ways that we are only just beginning to understand.

  11. 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.

  12. Chan Teaching and Learning: An Aesthetic Analysis of Its Educational Import

    ERIC Educational Resources Information Center

    Meng, Lingqi; Uhrmacher, P. Bruce

    2014-01-01

    This study examines the sudden enlightenment sect of Chan (or Zen in Japanese terms) in order to understand various aspects of teaching and learning in the Buddhist tradition in China. To unravel Chan's educational import, we analyze its aesthetic features through a Western lens in order to highlight significant aspects of the teaching/learning…

  13. A Life in Research, an Adventure in Creativity: An Interview with David W. Chan

    ERIC Educational Resources Information Center

    Henshon, Suzanna E.

    2011-01-01

    This article presents an interview with David W. Chan, founding director of the Program for the Gifted and Talented at the Chinese University of Hong Kong. Chan has worked at the university for nearly 30 years, first in the Department of Psychiatry and then in the Department of Educational Psychology. Currently, he is also an adjunct professor of…

  14. A Response to Ling-chi Wang, Elaine Kim, and Sucheng Chan.

    ERIC Educational Resources Information Center

    Takaki, Ronald

    1990-01-01

    Replies to every criticism in the foregoing essays of Ling-chi Wang, Elaine Kim, and Sucheng Chan. Endorses Chan's call for more in-depth research. Explains that the size of the book and the number of sources prevented closer annotation in the first edition. (DM)

  15. Mount St. Helens Volcano, WA, USA

    NASA Technical Reports Server (NTRS)

    1992-01-01

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

  16. 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,…

  17. 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,…

  18. Making sense of Mount St. Helens

    Treesearch

    Steve. Nash

    2010-01-01

    The eruption of Mount St. Helens in 1980 resulted in "a grand experiment that you could never have gotten anybody to fund," says Forest Service ecologist Charles Crisafulli. "Everything's new. It's a new landform." Unlike most misbehaving volcanoes, this one provided an accessible laboratory right along the Interstate-5 corridor, with the...

  19. Midwives in China: 'jie sheng po' to 'zhu chan shi'.

    PubMed

    Harris, Amanda; Belton, Suzanne; Barclay, Lesley; Fenwick, Jenny

    2009-04-01

    We explore the position of midwifery in contemporary China, and draw on fieldwork conducted in Shanxi and Sichuan Provinces during 2005 and 2006, the available literature in English and to a lesser extent in Mandarin. We also explore the historical antecedents to the present-day professional status, practices and position within the health-care system of midwifery in China. We consider the effect on midwifery of the place of biomedicine in the modernising project of the post-reform State, the shift of birth from the private to the public domain, the rise of the medical profession, the medicalisation of birth and the increasing use of technology, and trace changes in the nature of relations between midwives, doctors and the State from Imperial China to the present day. In particular, we examine the changes that have occurred as midwifery has moved from the arena of the lay practitioner ('jie sheng po') to the professional ('zhu chan shi'). We draw out and critique some ways that midwives act to differentiate themselves and lay claim to a variant body of practice-based knowledge, yet question the capacity of midwifery in China today to assert, in any substantial way, a professional identity that distinguishes it from medical obstetric practice.

  20. Analysis of caspase3 activation in ChanSu-induced apoptosis of ASTC-a-1 cells by fluorescence techniques

    NASA Astrophysics Data System (ADS)

    Sun, Lei; Chen, Tongsheng; Wang, Longxiang; Wang, Huiying

    2008-02-01

    ChanSu(CS), a traditional Chinese medicine, is composed of many chemical compoments. It is isolated from the dried white secretion of the auricular and skin glands of toads, and it has been widely used for treating the heart diseases and other systemic illnesses. However, it is difficult to judge antitumor effect of agents derived from ChanSu and the underlying mechanism of ChanSu inducing cell apoptosis is still unclear. This report was performed to explore the inhibitory effect and mechanism of ChanSu on human lung adenocarcinoma cells (ASTC-a-1). Fluorescence emission spectra and fluorescence resonance energy transfer (FRET) were used to study the caspase-3 activation during the ChanSu-induced human lung adenocarcinoma (ASTC-a-1) cell apoptosis. CCK-8 was used to assay the inhibition of ChanSu on the cell viability. The cells expressing stably with SCAT3 was used to examine if caspase-3 was activated by ChanSu using acceptor photobleaching technique. Our data showed that treatment of ASTC-a-1 cell with ChanSu resulted in the inhibition of viability and induction of apoptosis in a dose-dependent manner and the SCAT3 was almost cleaved 24 h after ChanSu treatment, implying that ChanSu induced cell apoptosis via a caspase-3-dependent death pathway. Our findings extend the knowledge about the cellular signaling mechanisms mediating ChanSu-induced apoptosis.

  1. 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.

  2. Mount St. Helens and Kilauea volcanoes

    USGS Publications Warehouse

    Barrat, J.

    1989-01-01

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

  3. 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

  4. 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…

  5. Comment on 'Mapping the dayside ionosphere to the magnetosphere according to particle precipitation characteristics' by Newell and Meng

    NASA Technical Reports Server (NTRS)

    Lockwood, M.; Smith, M. F.

    1993-01-01

    Newell and Meng (1992) present maps of the occurrence probability of various classifications of particle precipitation as seen in the dayside topside ionosphere. It is argued that these are maps of the magnetospheric regions, a contention with which their critics disagree. The latter conclude that, because of convection, any one population of particles seen at low altitudes will have originated from a wide variety of locations, and particle characteristics cannot be mapped back to those in the magnetosphere without detailed knowledge of both the convection and magnetic field. Steplike boundaries between the regions will arise from nonsteady-state conditions and cannot be envisaged as steady-state magnetospheric boundaries between two plasma populations. In their reply Newell and Meng contend that convection does not move plasma from the LLBL into the cusp. Most of the LLBL plasma comes from the magnetosheath, so the direction of plasma transfer is in the other direction.

  6. The Evaluation of Physical Stillness with Wearable Chest and Arm Accelerometer during Chan Ding Practice

    PubMed Central

    Chang, Kang-Ming; Chun, Yu-Teng; Chen, Sih-Huei; Lu, Luo; Su, Hsiao-Ting Jannis; Liang, Hung-Meng; Santhosh, Jayasree; Ching, Congo Tak-Shing; Liu, Shing-Hong

    2016-01-01

    Chan Ding training is beneficial to health and emotional wellbeing. More and more people have taken up this practice over the past few years. A major training method of Chan Ding is to focus on the ten Mailuns, i.e., energy points, and to maintain physical stillness. In this article, wireless wearable accelerometers were used to detect physical stillness, and the created physical stillness index (PSI) was also shown. Ninety college students participated in this study. Primarily, accelerometers used on the arms and chest were examined. The results showed that the PSI values on the arms were higher than that of the chest, when participants moved their bodies in three different ways, left-right, anterior-posterior, and hand, movements with natural breathing. Then, they were divided into three groups to practice Chan Ding for approximately thirty minutes. Participants without any Chan Ding experience were in Group I. Participants with one year of Chan Ding experience were in Group II, and participants with over three year of experience were in Group III. The Chinese Happiness Inventory (CHI) was also conducted. Results showed that the PSI of the three groups measured during 20–30 min were 0.123 ± 0.155, 0.012 ± 0.013, and 0.001 ± 0.0003, respectively (p < 0.001 ***). The averaged CHI scores of the three groups were 10.13, 17.17, and 25.53, respectively (p < 0.001 ***). Correlation coefficients between PSI and CHI of the three groups were −0.440, −0.369, and −0.537, respectively (p < 0.01 **). PSI value and the wearable accelerometer that are presently available on the market could be used to evaluate the quality of the physical stillness of the participants during Chan Ding practice. PMID:27447641

  7. The Evaluation of Physical Stillness with Wearable Chest and Arm Accelerometer during Chan Ding Practice.

    PubMed

    Chang, Kang-Ming; Chun, Yu-Teng; Chen, Sih-Huei; Lu, Luo; Su, Hsiao-Ting Jannis; Liang, Hung-Meng; Santhosh, Jayasree; Ching, Congo Tak-Shing; Liu, Shing-Hong

    2016-07-20

    Chan Ding training is beneficial to health and emotional wellbeing. More and more people have taken up this practice over the past few years. A major training method of Chan Ding is to focus on the ten Mailuns, i.e., energy points, and to maintain physical stillness. In this article, wireless wearable accelerometers were used to detect physical stillness, and the created physical stillness index (PSI) was also shown. Ninety college students participated in this study. Primarily, accelerometers used on the arms and chest were examined. The results showed that the PSI values on the arms were higher than that of the chest, when participants moved their bodies in three different ways, left-right, anterior-posterior, and hand, movements with natural breathing. Then, they were divided into three groups to practice Chan Ding for approximately thirty minutes. Participants without any Chan Ding experience were in Group I. Participants with one year of Chan Ding experience were in Group II, and participants with over three year of experience were in Group III. The Chinese Happiness Inventory (CHI) was also conducted. Results showed that the PSI of the three groups measured during 20-30 min were 0.123 ± 0.155, 0.012 ± 0.013, and 0.001 ± 0.0003, respectively (p < 0.001 ***). The averaged CHI scores of the three groups were 10.13, 17.17, and 25.53, respectively (p < 0.001 ***). Correlation coefficients between PSI and CHI of the three groups were -0.440, -0.369, and -0.537, respectively (p < 0.01 **). PSI value and the wearable accelerometer that are presently available on the market could be used to evaluate the quality of the physical stillness of the participants during Chan Ding practice.

  8. 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)

  9. 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

  10. Silent Illumination: A Study on Chan (Zen) Meditation, Anxiety, and Musical Performance Quality

    ERIC Educational Resources Information Center

    Lin, Peter; Chang, Joanne; Zemon, Vance; Midlarsky, Elizabeth

    2008-01-01

    This study investigated the effects of Chan (Zen) meditation on musical performance anxiety and musical performance quality. Nineteen participants were recruited from music conservatories and randomly assigned to either an eight-week meditation group or a wait-list control group. After the intervention, all participants performed in a public…

  11. Spatially Nonlinear Interdependence of Alpha-Oscillatory Neural Networks under Chan Meditation

    PubMed Central

    Chang, Chih-Hao

    2013-01-01

    This paper reports the results of our investigation of the effects of Chan meditation on brain electrophysiological behaviors from the viewpoint of spatially nonlinear interdependence among regional neural networks. Particular emphasis is laid on the alpha-dominated EEG (electroencephalograph). Continuous-time wavelet transform was adopted to detect the epochs containing substantial alpha activities. Nonlinear interdependence quantified by similarity index S(X∣Y), the influence of source signal Y on sink signal X, was applied to the nonlinear dynamical model in phase space reconstructed from multichannel EEG. Experimental group involved ten experienced Chan-Meditation practitioners, while control group included ten healthy subjects within the same age range, yet, without any meditation experience. Nonlinear interdependence among various cortical regions was explored for five local neural-network regions, frontal, posterior, right-temporal, left-temporal, and central regions. In the experimental group, the inter-regional interaction was evaluated for the brain dynamics under three different stages, at rest (stage R, pre-meditation background recording), in Chan meditation (stage M), and the unique Chakra-focusing practice (stage C). Experimental group exhibits stronger interactions among various local neural networks at stages M and C compared with those at stage R. The intergroup comparison demonstrates that Chan-meditation brain possesses better cortical inter-regional interactions than the resting brain of control group. PMID:24489583

  12. Spatially Nonlinear Interdependence of Alpha-Oscillatory Neural Networks under Chan Meditation.

    PubMed

    Lo, Pei-Chen; Chang, Chih-Hao

    2013-01-01

    This paper reports the results of our investigation of the effects of Chan meditation on brain electrophysiological behaviors from the viewpoint of spatially nonlinear interdependence among regional neural networks. Particular emphasis is laid on the alpha-dominated EEG (electroencephalograph). Continuous-time wavelet transform was adopted to detect the epochs containing substantial alpha activities. Nonlinear interdependence quantified by similarity index S(X∣Y), the influence of source signal Y on sink signal X, was applied to the nonlinear dynamical model in phase space reconstructed from multichannel EEG. Experimental group involved ten experienced Chan-Meditation practitioners, while control group included ten healthy subjects within the same age range, yet, without any meditation experience. Nonlinear interdependence among various cortical regions was explored for five local neural-network regions, frontal, posterior, right-temporal, left-temporal, and central regions. In the experimental group, the inter-regional interaction was evaluated for the brain dynamics under three different stages, at rest (stage R, pre-meditation background recording), in Chan meditation (stage M), and the unique Chakra-focusing practice (stage C). Experimental group exhibits stronger interactions among various local neural networks at stages M and C compared with those at stage R. The intergroup comparison demonstrates that Chan-meditation brain possesses better cortical inter-regional interactions than the resting brain of control group.

  13. The clinical and experimental studies of ChanLe Chongji for reducing bleeding after abortion.

    PubMed

    Zhao, R; Ding, Y; Hu, Y

    1999-01-01

    This report presents the results of the clinical and experimental studies conducted to determine the effectiveness of ChanLe Chongji, a Chinese medicine. ChanLe Chongji is believed to promote uterine contraction, stop bleeding, resist bacteria and diminish inflammation. The clinical study was done on 100 women with the following characteristics: under 35 years old; in good health; no contraindication to mifepristone and prostaglandin; normal menses for the past 3 months; not more than 49 days after amenorrhea; intrauterine pregnancy diagnosed by urine human chorionic gonadotropin or ultrasonography. These women were divided into two groups (treated group and control group). An experimental portion of the study included kunming mice weighing 25-30 g and on Wistar rats weighing 180-230 g. The results of the clinical study revealed that the mean bleeding period in the treated group was 8.4 days, while it was 13.3 days in the control group. The mean complete abortion rate was 95% in the treated group and 88% in the control group. A pharmacodynamic test was conducted during the animal experimental portion to comprehend the mechanism of hemostasis. It showed that ChanLe Chongji could increase uterine contraction and stop bleeding; maximal dosage also demonstrated that ChanLe Chongji was safe in clinical use.

  14. Silent Illumination: A Study on Chan (Zen) Meditation, Anxiety, and Musical Performance Quality

    ERIC Educational Resources Information Center

    Lin, Peter; Chang, Joanne; Zemon, Vance; Midlarsky, Elizabeth

    2008-01-01

    This study investigated the effects of Chan (Zen) meditation on musical performance anxiety and musical performance quality. Nineteen participants were recruited from music conservatories and randomly assigned to either an eight-week meditation group or a wait-list control group. After the intervention, all participants performed in a public…

  15. Rapid weakening of Typhoon Chan-Hom (2015) in a monsoon gyre

    NASA Astrophysics Data System (ADS)

    Liang, Jia; Wu, Liguang; Gu, Guojun; Liu, Qingyuan

    2016-08-01

    A monsoon gyre is a low-frequency cyclonic circulation over the western North Pacific, which plays important roles in tropical cyclone formation and motion. This study shows that the interaction between a monsoon gyre and a tropical cyclone can lead to a sudden weakening of the tropical cyclone through an observational analysis of Typhoon Chan-Hom (2015). Typhoon Chan-Hom (2015) initially moved westward along ~10°N and sharply turned northeastward in the Philippine Sea at 0000 UTC 3 July. Its intensity decreased by 10.3 m s-1 within 12 h during the sudden northward turn. Such a rapid weakening event was failed to predict in all of the operational forecasts. It is found that Chan-Hom was coalescing with a large-scale monsoon gyre on the intraseasonal (15-30 day) timescale, while it experienced the sudden track change and rapid intensity weakening. The weak and loosely organized convection on the eastern side of the monsoon gyre at 1200 UTC 2 July rapidly enhanced into the well-organized convection within 6 h. The strong convection maintaining from 1800 UTC 2 July to 0600 UTC 3 July enhanced inflows outside the radius of 500 km from the tropical cyclone center, which prevented the inward transportation of mass and moisture into Chan-Hom, leading to the collapsing of the eastern part of the eyewall. As a result, Chan-Hom underwent the rapid weakening even under a large-scale environment favorable for intensification. The study suggests that the rapid weakening of a tropical cyclone can result from its interaction with a monsoon gyre.

  16. 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)

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Data analysis of the high frequency surface wave radar during typhoon Chan-hom

    NASA Astrophysics Data System (ADS)

    Li, Cheng; Wang, Hui; Gao, Jia; Li, Huan; Wang, Guosong; Pan, Song; Fan, Wenjing; Liu, Kexiu; Zhao, Chen; Qi, Anxiang

    2017-01-01

    Multi-frequency high frequency radar with small circular array was deployed in Zhujiajian and Shengshan to detect the winds, waves, and currents in the overlapping area operationally in 2007. No. 1509 typhoon Chan-hom landed in the coastal areas of Jujiajian, and then moved north by east, passing the radar detection area. This paper compared the radar observed data to anchored-buoy observed data and ASCAT satellite remote sensing large area wind data respectively. The results of comparison indicated that radar basically reflected the real distribution of wind and current of Zhoushan area during typhoon Chan-hom, showing the radar is qualified to detect the winds and currents under complex marine conditions.

  2. Normal Vector Projection Method used for Convex Optimization of Chan-Vese Model for Image Segmentation

    NASA Astrophysics Data System (ADS)

    Wei, W. B.; Tan, L.; Jia, M. Q.; Pan, Z. K.

    2017-01-01

    The variational level set method is one of the main methods of image segmentation. Due to signed distance functions as level sets have to keep the nature of the functions through numerical remedy or additional technology in an evolutionary process, it is not very efficient. In this paper, a normal vector projection method for image segmentation using Chan-Vese model is proposed. An equivalent formulation of Chan-Vese model is used by taking advantage of property of binary level set functions and combining with the concept of convex relaxation. Threshold method and projection formula are applied in the implementation. It can avoid the above problems and obtain a global optimal solution. Experimental results on both synthetic and real images validate the effects of the proposed normal vector projection method, and show advantages over traditional algorithms in terms of computational efficiency.

  3. Fu-Chan Wei—Surgeon, Innovator, and Leader of the Legendary Chang Gung Microsurgery Center

    PubMed Central

    AL Deek, Nidal Farhan

    2016-01-01

    Fu-Chan Wei is a world-renowned plastic and reconstructive surgeon. He is clearly one of the most influential and innovative surgeons in the history of plastic surgery. The Taiwanese legend is the innovator of the osteoseptocutaneous fibula flap, which revolutionized the reconstruction of composite bone and soft tissue defects in the jaw and extremities. He has pioneered several perforator flaps, including the free style variety. He has taken toe-to-hand microsurgical transplantation to a whole new level. He is not only recognized for his surgical skills and clinical innovations, but also for his vision, leadership, and teaching. The establishment and development of the famous Microsurgery Center at Chang Gung Memorial Hospital is unparalleled anywhere. The international fellowship program in microsurgery there remains the envy of all microsurgical trainees. Dr. Wei and his colleagues have trained and influenced more than 1,500 surgeons from all over the world. The aim of this video article is to share what we learned by interviewing Fu-Chan Wei at Chang Gung. The story of Fu Chan Wei, his colleagues, and the development of the Microsurgery Center in Taiwan is worth knowing. PMID:27757352

  4. 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.

  5. 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).

  6. 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…

  7. Volcano ecology: flourishing on the flanks of Mount St. Helens

    Treesearch

    Rhonda Mazza; Charlie Crisafulli

    2016-01-01

    Mount St. Helens’ explosive eruption on May 18, 1980, was a pivotal moment in the field of disturbance ecology. The subsequent sustained, integrated research effort has shaped the development of volcano ecology, an emerging field of focused research. Excessive heat, burial, and impact force are some of the disturbance mechanisms following an eruption. They are also...

  8. 25 years of ecological change at Mount St. Helens.

    Treesearch

    V.H. Dale; C.M. Crisafulli; F.J. Swanson

    2005-01-01

    18 May 2005 marks the 25th anniversary of the massive eruption of Mount St. Helens. This eruption involved diverse geological processes (1) that disturbed forests, meadows, lakes, an drivers (2) (see the figure). A huge landslide and searing flows of hot gases and pumic framents (pyroclastic flows) inundated 60 km2 of land, obliterating...

  9. 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)

  10. Forest development following mudflow deposition, Mount St. Helens, Washington

    Treesearch

    Marc H. Weber; Keith S. Hadley; Peter M. Frenzen; Jerry F. Franklin

    2006-01-01

    Volcanic mudflows are locally important disturbance agents in the Pacific Northwest rarely studied within the context of forest succession. We describe 18 years (1981–1999) of forest development on the Muddy River mudflow deposit following the 1980 eruption of Mount St. Helens using permanent plot data collected along two transects traversing the Cedar Flats river...

  11. 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)

  12. Mount St. Helens 30 years later: a landscape reconfigured.

    Treesearch

    Rhonda Mazza

    2010-01-01

    On May 18, 1980, after two months of tremors, Mount St. Helens erupted spectacularly and profoundly changed a vast area surrounding the volcano. The north slope of the mountain catastrophically failed, forming the largest landslide witnessed in modern times. The largest lobe of this debris avalanche raced 14 miles down the Toutle River...

  13. 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.

  14. Mount St. Helens: Still erupting lessons 31 years later

    Treesearch

    Rhonda Mazza; Charlie Crisafulli; Fred Swanson

    2011-01-01

    The massive volcanic eruption of Mount St. Helens 31 years ago provided the perfect backdrop for studying the earliest stages of forest development. Immediately after the eruption, some areas of the blast area were devoid of life. On other parts of the volcanic landscape, many species survived, although their numbers were greatly reduced. Reassembly began at many...

  15. 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…

  16. 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…

  17. 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)

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

    PubMed

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

    1975-02-07

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

  19. 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.

  20. 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.

  1. 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.

  2. Apoptosis induction of human lung carcinoma cells by Chan Su (Venenum Bufonis) through activation of caspases.

    PubMed

    Yun, Hye Ri; Yoo, Hwa Seung; Shin, Dong Yeok; Hong, Su Hyun; Kim, Jong-Hwan; Cho, Chong Kwan; Choi, Yung Hyun

    2009-09-01

    Chan Su is a traditional Chinese medicine prepared from the dried white secretion of the auricular and skin glands of toads, and has been used as an oriental drug for the treatment of a number of diseases, including cancer. In this study, the potential of Chan Su (skin of Venenum Bufonis) to induce apoptosis in human lung carcinoma A549 cells was investigated. Treatment of A549 cells with skin of Venenum Bufonis resulted in the inhibition of cell growth and viability and the induction of apoptosis, which was shown by trypan blue counts, MTT assay, DAPI staining and flow cytometry analysis. The increase in apoptosis that was induced by skin of Venenum Bufonis was correlated with down-regulation of anti-apoptotic Bcl-2 expression, up-regulation of pro-apoptotic Fas ligand and death receptor 4, and a decrease in the mitochondrial membrane potential. Skin of Venenum Bufonis treatment induced the proteolytic activation of caspases and a concomitant degradation of poly(ADP-ribose)-polymerase and beta-catenin protein. Cleavage of Bid and a down-regulation of the inhibitor of apoptosis family proteins were also observed in skin of Venenum Bufonis-treated A549 cells. Data from this study indicates that SVB induces the apoptosis of A549 cells through a signaling cascade of death receptor-mediated extrinsic and mitochondria-mediated intrinsic caspase pathways.

  3. A Novel Small-Molecule Inhibitor of the Mycobacterium tuberculosis Demethylmenaquinone Methyltransferase MenG Is Bactericidal to Both Growing and Nutritionally Deprived Persister Cells.

    PubMed

    Sukheja, Paridhi; Kumar, Pradeep; Mittal, Nisha; Li, Shao-Gang; Singleton, Eric; Russo, Riccardo; Perryman, Alexander L; Shrestha, Riju; Awasthi, Divya; Husain, Seema; Soteropoulos, Patricia; Brukh, Roman; Connell, Nancy; Freundlich, Joel S; Alland, David

    2017-02-14

    Active tuberculosis (TB) and latent Mycobacterium tuberculosis infection both require lengthy treatments to achieve durable cures. This problem has partly been attributable to the existence of nonreplicating M. tuberculosis "persisters" that are difficult to kill using conventional anti-TB treatments. Compounds that target the respiratory pathway have the potential to kill both replicating and persistent M. tuberculosis and shorten TB treatment, as this pathway is essential in both metabolic states. We developed a novel respiratory pathway-specific whole-cell screen to identify new respiration inhibitors. This screen identified the biphenyl amide GSK1733953A (DG70) as a likely respiration inhibitor. DG70 inhibited both clinical drug-susceptible and drug-resistant M. tuberculosis strains. Whole-genome sequencing of DG70-resistant colonies identified mutations in menG (rv0558), which is responsible for the final step in menaquinone biosynthesis and required for respiration. Overexpression of menG from wild-type and DG70-resistant isolates increased the DG70 MIC by 4× and 8× to 30×, respectively. Radiolabeling and high-resolution mass spectrometry studies confirmed that DG70 inhibited the final step in menaquinone biosynthesis. DG70 also inhibited oxygen utilization and ATP biosynthesis, which was reversed by external menaquinone supplementation. DG70 was bactericidal in actively replicating cultures and in a nutritionally deprived persistence model. DG70 was synergistic with the first-line TB drugs isoniazid, rifampin, and the respiratory inhibitor bedaquiline. The combination of DG70 and isoniazid completely sterilized cultures in the persistence model by day 10. These results suggest that MenG is a good therapeutic target and that compounds targeting MenG along with standard TB therapy have the potential to shorten TB treatment duration.IMPORTANCE This study shows that MenG, which is responsible for the last enzymatic step in menaquinone biosynthesis, may be a

  4. Effect of Chinese medicines Chan Su, Asian ginseng, Siberian ginseng, and American ginseng on a new digoxin immunoassay based on luminescent oxygen channeling technology.

    PubMed

    Dasgupta, Amitava; Syklawer, Erica; Johnson, Myrtle; Hwang, Shen-An; Boyd, Sydney A; Actor, Jeffrey K

    2011-10-01

    Chan Su, Asian ginseng, Siberian ginseng, and American ginseng are known to interfere with various digoxin immunoassays. Recently, a homogeneous sequential chemiluminescent assay for digoxin based on the luminescent oxygen channeling technology (LOCI digoxin) for application on the Dimension and Vista platform has been introduced into the market. The effects of interference by Chan Su and various ginsengs on this new immunoassay have not yet been reported. Aliquots of a drug-free serum pool were supplemented with Chan Su, Asian ginseng, Siberian ginseng, and American ginseng representing the expected in vivo concentrations after normal usage and cases of overdose. Serum digoxin concentrations were measured using the LOCI digoxin assay on the Vista 1500 analyzer. We also prepared 3 digoxin pools from patients receiving digoxin. Two digoxin pools were supplemented with these traditional medicines to investigate their effect on serum digoxin measurements. Mice were fed Chan Su extract to determine the potential of in vivo derived interfering factors. The possibility of eliminating interference of Chan Su on serum digoxin measurement was also investigated, by measuring free digoxin concentration after supplementing aliquots of the third digoxin pool with various amounts of Chan Su extract. A clinically significant interference by Chan Su with serum digoxin measurement was observed using the LOCI digoxin assay. The various ginsengs demonstrated negligible effects. In addition, apparent digoxin concentrations were observed in sera of mice after feeding them with Chan Su; the half-life of digoxin-like immunoreactive components was approximately 1 hour. Moreover, serum digoxin concentrations were significantly elevated in the presence of Chan Su, whereas the various ginsengs exhibited no effect. Monitoring free digoxin can only partly eliminate the interference of Chan Su in serum digoxin measurement. Chan Su interferes with serum digoxin measurement using the LOCI Digoxin

  5. Coastal evolution between two giant rivers: The Chan May embayment in central Vietnam

    NASA Astrophysics Data System (ADS)

    Gouramanis, C.; Switzer, A.; Bristow, C.; Pham, D. T.; Mauz, B.; Pile, J.; Doan, L. D.; Hoang, Q. D.; Ngo, C. K.; Dao, N.; Polivka, P.; Soria, L.; Lee, Y.; Sloss, C.; Hoang, L. V.

    2015-12-01

    The coastal landscapes of Vietnam are dominated in the north and south by the very large Red and Mekong rivers. Central Vietnam, in contrast, has few large rivers that flow to the coastal zone. This coupled with the high relief (>1500 m) of the granitic Truong Son Range and shallow gradient continental shelf, has produced two different coastal geomorphologies. The first is a shallow basin infilled with a sequence of parallel, arcuate beach ridges, and the second includes the development of shore-parallel spits and coastal lagoons. All systems are Holocene in age and we present evidence of the Holocene evolution of the northward-facing, beach ridge strandplain located in the Chan May embayment, approximately 35 km north of Danang. This embayment is relatively small (5 km long at the beach and with a beach ridge sequence that spans 11 km from the modern beach to the base of the Truong Son Range) compared to other beach ridge strandplains to the north and south and serves as an analogue for the evolution of these larger systems. The Holocene evolution of the embayment was resolved using Ground Penetrating Radar (GPR), high-resolution sedimentological analysis and quartz Optically Stimulated Luminescence were used to investigate the internal stratigraphy and chronological development of the beach ridges at Chan May. The strandplain contains uniform, clean quartz-rich sediment interspersed by thin heavy mineral rich bands forming shallow-gradient beach ridges that have steadily prograded seaward during the regression after the mid-Holocene sea level highstand. As the beach ridges prograded seaward, a small river feeding directly from the Truong Son Range meandered across the strandplain and significantly modified the embayment. Recently, the river has become much reduced due to anthropogenic modification of the river and landscape. Prior to the Holocene marine highstand, the area was similarly characterized by a surface of prograding beach ridges that were eroded by

  6. 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

  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. Wavelet-based improved Chan-Vese model for image segmentation

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaoli; Zhou, Pucheng; Xue, Mogen

    2016-10-01

    In this paper, a kind of image segmentation approach which based on improved Chan-Vese (CV) model and wavelet transform was proposed. Firstly, one-level wavelet decomposition was adopted to get the low frequency approximation image. And then, the improved CV model, which contains the global term, local term and the regularization term, was utilized to segment the low frequency approximation image, so as to obtain the coarse image segmentation result. Finally, the coarse segmentation result was interpolated into the fine scale as an initial contour, and the improved CV model was utilized again to get the fine scale segmentation result. Experimental results show that our method can segment low contrast images and/or inhomogeneous intensity images more effectively than traditional level set methods.

  10. A Novel Small-Molecule Inhibitor of the Mycobacterium tuberculosis Demethylmenaquinone Methyltransferase MenG Is Bactericidal to Both Growing and Nutritionally Deprived Persister Cells

    PubMed Central

    Sukheja, Paridhi; Kumar, Pradeep; Mittal, Nisha; Li, Shao-Gang; Singleton, Eric; Russo, Riccardo; Perryman, Alexander L.; Shrestha, Riju; Awasthi, Divya; Husain, Seema; Soteropoulos, Patricia; Brukh, Roman; Connell, Nancy; Freundlich, Joel S.

    2017-01-01

    ABSTRACT Active tuberculosis (TB) and latent Mycobacterium tuberculosis infection both require lengthy treatments to achieve durable cures. This problem has partly been attributable to the existence of nonreplicating M. tuberculosis “persisters” that are difficult to kill using conventional anti-TB treatments. Compounds that target the respiratory pathway have the potential to kill both replicating and persistent M. tuberculosis and shorten TB treatment, as this pathway is essential in both metabolic states. We developed a novel respiratory pathway-specific whole-cell screen to identify new respiration inhibitors. This screen identified the biphenyl amide GSK1733953A (DG70) as a likely respiration inhibitor. DG70 inhibited both clinical drug-susceptible and drug-resistant M. tuberculosis strains. Whole-genome sequencing of DG70-resistant colonies identified mutations in menG (rv0558), which is responsible for the final step in menaquinone biosynthesis and required for respiration. Overexpression of menG from wild-type and DG70-resistant isolates increased the DG70 MIC by 4× and 8× to 30×, respectively. Radiolabeling and high-resolution mass spectrometry studies confirmed that DG70 inhibited the final step in menaquinone biosynthesis. DG70 also inhibited oxygen utilization and ATP biosynthesis, which was reversed by external menaquinone supplementation. DG70 was bactericidal in actively replicating cultures and in a nutritionally deprived persistence model. DG70 was synergistic with the first-line TB drugs isoniazid, rifampin, and the respiratory inhibitor bedaquiline. The combination of DG70 and isoniazid completely sterilized cultures in the persistence model by day 10. These results suggest that MenG is a good therapeutic target and that compounds targeting MenG along with standard TB therapy have the potential to shorten TB treatment duration. PMID:28196957

  11. Satellite Observations of the Mt. St. Helens Eruption of 18 May 1980.

    DTIC Science & Technology

    1981-08-21

    and doubtless corresponded to the establishment of the Plinian column which dominated the later eruption period. Although the motion of overlying ash...AO-A1GS 784 AEROSPACE CORP EL SEGUNDO CA SPACE SCIENCES LAB F/B 8/7 SATELLITE OBSERVATIONS OF THE MT. ST. HELENS ERUPTION OF SB MAT--ETCIU)AUG 81 C J... Eruption of Mt. St. Helens Mt. St. Helens Satellite Observations Eruption Chronology Volcanic Eruptions 20. ABSTRACT (Continue on reverse side If

  12. A Chinese Chan-based mind-body intervention for patients with depression.

    PubMed

    Chan, Agnes S; Wong, Queenie Y; Sze, Sophia L; Kwong, Patrick P K; Han, Yvonne M Y; Cheung, Mei-Chun

    2012-12-15

    Given the recent growing interest and encouraging findings in studies of alternative treatments for depression, the present randomized controlled trial study aimed to compare the effect of a newly developed Chinese Chan-based Dejian Mind-Body Intervention (DMBI) with the Cognitive Behavioral Therapy (CBT) on improving depressive symptoms in patients with depression. Seventy-five participants diagnosed with major depressive disorder were randomly assigned to receive either 10-session CBT or DMBI, or placed on a waitlist. Pre-post measurements included record of anti-depressants treatment, ratings by psychiatrists who were blinded to the experimental design and self-report on mood measures, and performance in a cognitive test tapping concentration ability. Both the CBT and DMBI groups demonstrated significantly reduced overall depressive syndrome after intervention at large effect size (0.93-1.10). Furthermore, the DMBI group (p<0.05), but not the CBT or waitlist groups, demonstrated significant reduction in intake of anti-depressants, and significant improvement in specific depression-related symptoms including difficulty in concentration (p=0.002), and problems in gastrointestinal health (p=0.02) and overall sleep quality (p<0.001). This study has provided some evidence for the short-term effect of the DMBI on Chinese population. Its long-term effect on a larger sample and on Caucasian population warrants further investigation. The present findings suggest that a Chinese Chan-based Mind-Body intervention has positive effects on improving mood and health conditions of individuals with depression. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. 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.

  14. 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.

  15. 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).

  16. Imaging the Mount St. Helens Magmatic Systems using Magnetotellurics

    NASA Astrophysics Data System (ADS)

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

    2009-05-01

    A detailed magnetotelluric survey of Mount St. Helens shows that a conduit like zone of high electrical conductivity beneath the volcano is connected to a larger zone of high conductivity at 15 km depth that extends eastward to Mount Adams. We interpret this zone to be a region of connected melt that acts as the reservoir for the silicic magma being extruded at the time of the magnetotelluric survey. This interpretation is consistent with a mid-crustal origin for the silicic component of the Mount St. Helens' magmas and provides an elegant explanation for a previously unexplained feature of the seismicity observed at the time of the catastrophic eruption in 1980. This zone of high mid-crustal conductivity extends northwards to near Mount Rainier suggesting a single region of connected melt comparable in size to the largest silicic volcanic systems known.

  17. Helen Wingate: pioneering a woman's role in urology.

    PubMed

    Ramsey, S; Aitchison, M

    2007-02-01

    When the British Association of Urological Surgeons was founded in 1945, 2 female founder members registered. One of these was Helen Wingate, Associate Specialist in Urology at Glasgow Royal Infirmary and Consultant Urologist and General Surgeon at Redlands Hospital for Women, and a pioneer of women in urology. The early days of urology as a specialty at Glasgow Royal Infirmary, and the pioneering role played by Dr Wingate as a female consultant in a new surgical speciality are described in this article.

  18. Lead 210 and polonium 210 in Mount St. Helens ash

    NASA Astrophysics Data System (ADS)

    Nevissi, A. E.

    1984-07-01

    During the Mount St. Helens eruptions, lead 210 and polonium 210 were measured in volcanic ash samples. Polonium 210 was consistently higher than lead 210 in all samples, with the 210Po/210Pb ratios ranging from 2 to 12. The overequilibrium of the ratios is due to the enrichment of polonium compounds in the volcanic gases from hot magma relative to less volatile lead compounds.

  19. 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.

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

    USGS Publications Warehouse

    Chadwick, W.W.; 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.

  1. Fitness Assessment Comparison Between the "Jackie Chan Action Run" Videogame, 1-Mile Run/Walk, and the PACER.

    PubMed

    Haddock, Bryan; Siegel, Shannon; Costa, Pablo; Jarvis, Sarah; Klug, Nicholas; Medina, Ernie; Wilkin, Linda

    2012-06-01

    The purpose of this study was to examine whether a correlation existed among the scores of the "Jackie Chan Studio Fitness(™) Action Run" active videogame (XaviX(®), SSD Company, Ltd., Kusatsu, Japan), the 1-mile run/walk, and Progressive Aerobic Cardiovascular Endurance Run (PACER) aerobic fitness tests of the FITNESSGRAM(®) (The Cooper Institute, Dallas, TX) in order to provide a potential alternative testing method for days that are not environmentally desirable for outdoor testing. Participants were a convenience sample from physical education classes of students between the ages of 10 and 15 years. Participants (n=108) were randomly assigned to one of three groups with the only difference being the order of testing. The tests included the "Jackie Chan Action Run" active videogame, the 1-mile run/walk, and the PACER. Testing occurred on three different days during the physical education class. Rating of perceived exertion (RPE) was reported. Significant correlations (r=-0.598 to 0.312) were found among the three aerobic fitness tests administered (P<0.05). The RPE for the "Jackie Chan Action Run" was lower than the RPE for the 1-mile run/walk and the PACER (3.81±1.89, 5.93±1.77, and 5.71±2.14, respectively). The results suggest that the "Jackie Chan Action Run" test could be an alternative to the 1-mile run/walk and PACER, allowing physical education teachers to perform aerobic fitness testing in an indoor setting that requires less space. Also, children may be more willing to participate in the "Jackie Chan Action Run" based on the lower RPE.

  2. Ecological responses to the 1980 eruptions of Mount St. Helens: forward and preface.

    Treesearch

    Virginia H. Dale; Frederick J. Swanson; Charles M. Crisafulli

    2005-01-01

    When Mount St. Helens erupted on May 18, 1980, it did more than just reconfigure a large piece of Cascadian landscape. It also led to dramatic revisions in our perspectives on disturbances, secondary succession, and forestry practices. The Mount St. Helens landscape turned out to be a far more complex place than the "moonscape" that it initially appeared to...

  3. 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)

  4. 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)

  5. 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…

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

    USDA-ARS?s Scientific Manuscript database

    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...

  7. A Chinese Chan-based Mind-Body Intervention Improves Memory of Older Adults

    PubMed Central

    Chan, Agnes S.; Cheung, Winnie K.; Yeung, Michael K.; Woo, Jean; Kwok, Timothy; Shum, David H. K.; Yu, Ruby; Cheung, Mei-chun

    2017-01-01

    There is growing interest in the adoption of lifestyle interventions to remediate age-related declines in memory functioning and physical and psychological health among older adults. This study aimed to investigate whether a Chinese Chan-based lifestyle intervention, the Dejian Mind-Body Intervention (DMBI), leads to positive benefits for memory functioning in older adults. Fifty-six adults aged 60 years or older with subjective memory complaints (SMC) were randomly assigned to receive the DMBI or a control intervention (i.e., a conventional memory intervention; MI) once a week for 10 weeks; 48 of the adults completed the intervention. Participants’ verbal and visual memory functioning before and after the intervention were compared. In addition, changes in the participants’ subjective feelings about their memory performance and physical and psychological health after the intervention were examined. The results showed that both the DMBI and MI resulted in significant improvements in both verbal and visual memory functioning and that the extent of the improvements was correlated with participants’ level of performance at baseline. In addition, compared to the MI group, the DMBI group had significantly greater improvements in subjective physical and psychological health after the intervention. In summary, the present findings support the potential of the DMBI as an alternative lifestyle intervention for improving memory functioning, subjective physical and psychological health of older adults with SMC. PMID:28659789

  8. 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

  9. First record of Puerulus mesodontus Chan, Ma & Chu, 2013 (Crustacea, Decapoda, Achelata, Palinuridae) from south of Java, Indonesia.

    PubMed

    Wardiatno, Yusli; Hakim, Agus Alim; Mashar, Ali; Butet, Nurlisa Alias; Adrianto, Luky; Farajallah, Achmad

    2016-01-01

    Three specimens of Puerulus mesodontus Chan, Ma & Chu, 2013 (Crustacea, Decapoda, Achelata, Palinuridae) were collected from Palabuhanratu Bay, southern Java, Indonesia. There is no previous record on the presence of the species in Indonesia. This finding represents the first record of this species in Java, Indonesia, and confirms that the species is present in the Indian Ocean. The morphological characters of the species are described. This paper contains a new distribution record of a lobster species from Indonesian waters.

  10. Critical Examination of the Article Impulse Noise Injury Prediction Based on the Cochlear Energy by Zagadou, Chan, Ho, and Shelly

    DTIC Science & Technology

    2017-04-01

    matched the human ear’s characteristics and thereby improved the model’s performance in calculating various transfer functions. The goal was...Energy by Zagadou, Chan, Ho, and Shelly by G Richard Price and Joel T Kalb Human Research and Engineering Directorate, ARL Charles R Jokel US...Kalb, and Charles R Jokel 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) US

  11. The Chandra Planetary Nebula Survey (ChanPlaNS). II. X-Ray Emission from Compact Planetary Nebulae

    NASA Astrophysics Data System (ADS)

    Freeman, M.; Montez, R., Jr.; Kastner, J. H.; Balick, B.; Frew, D. J.; Jones, D.; Miszalski, B.; Sahai, R.; Blackman, E.; Chu, Y.-H.; De Marco, O.; Frank, A.; Guerrero, M. A.; Lopez, J. A.; Zijlstra, A.; Bujarrabal, V.; Corradi, R. L. M.; Nordhaus, J.; Parker, Q. A.; Sandin, C.; Schönberner, D.; Soker, N.; Sokoloski, J. L.; Steffen, M.; Toalá, J. A.; Ueta, T.; Villaver, E.

    2014-10-01

    We present results from the most recent set of observations obtained as part of the Chandra X-ray observatory Planetary Nebula Survey (ChanPlaNS), the first comprehensive X-ray survey of planetary nebulae (PNe) in the solar neighborhood (i.e., within ~1.5 kpc of the Sun). The survey is designed to place constraints on the frequency of appearance and range of X-ray spectral characteristics of X-ray-emitting PN central stars and the evolutionary timescales of wind-shock-heated bubbles within PNe. ChanPlaNS began with a combined Cycle 12 and archive Chandra survey of 35 PNe. ChanPlaNS continued via a Chandra Cycle 14 Large Program which targeted all (24) remaining known compact (R neb <~ 0.4 pc), young PNe that lie within ~1.5 kpc. Results from these Cycle 14 observations include first-time X-ray detections of hot bubbles within NGC 1501, 3918, 6153, and 6369, and point sources in HbDs 1, NGC 6337, and Sp 1. The addition of the Cycle 14 results brings the overall ChanPlaNS diffuse X-ray detection rate to ~27% and the point source detection rate to ~36%. It has become clearer that diffuse X-ray emission is associated with young (lsim 5 × 103 yr), and likewise compact (R neb <~ 0.15 pc), PNe with closed structures and high central electron densities (ne >~ 1000 cm-3), and is rarely associated with PNe that show H2 emission and/or pronounced butterfly structures. Hb 5 is one such exception of a PN with a butterfly structure that hosts diffuse X-ray emission. Additionally, two of the five new diffuse X-ray detections (NGC 1501 and NGC 6369) host [WR]-type central stars, supporting the hypothesis that PNe with central stars of [WR]-type are likely to display diffuse X-ray emission.

  12. Deep long-period earthquakes (DLPs) beneath Mount St. Helens

    NASA Astrophysics Data System (ADS)

    Han, J.; Vidale, J. E.; Schmidt, D. A.; Creager, K. C.; Houston, H.

    2016-12-01

    Volcanic deep long-period earthquakes (DLPs), located in the mid- to lower-crust and uppermost mantle, have been observed for a long time but remain poorly understood. Several hypotheses have been proposed to explain these DLPs, including dehydration embrittlement, the flow of magma and/or magmatic fluid, and the cooling of magma. We use seismic data from the iMUSH experiment (imaging Magma Under St Helens) and the nearby PNSN permanent network to study the DLPs beneath Mount St. Helens. Catalog DLPs are taken as templates to search for repeating events that were too small to be routinely detected. For the period 2007 to 2015, we have detected 239 DLPs, compared to only 17 events that were previously in the catalog. Three templates from the catalog are isolated one-offs, while all other templates produced matches, identifying loci of repeated activity. Many of the DLPs occur as bursts or swarms within tens of seconds to several minutes. Overall, the detected DLPs show long-term episodic bursts of activity with a recurrence period of roughly fourteen months. Several, but not all, episodes are temporally correlated with the subduction zone tremor and slow slip (ETS) west of St. Helens, which is also seen on GPS records. Several of these episodes also show a plausible connection with shallow seismicity. Preliminary analysis shows an elevated rate of DLPs at times of compressional volumetric tidal stress, suggesting their possible association with magmatic and/or fluid activity. We are stacking waveforms of the detected events for the iMUSH broadband stations and analyzing their waveform amplitude and polarization, to understand the focal mechanism of DLPs. We also hope to understand the complicated multipathing and attenuation associated with the midcrust directly under the volcano.

  13. 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.

  14. "Validation of WRF Forecasts for the Development of Hurricane Helene"

    NASA Astrophysics Data System (ADS)

    Folmer, M. J.; Pasken, R. W.; Anderson, B. E.

    2008-12-01

    Each year, about 50 African Easterly Waves (AEWs) move off the West African coast and traverse the tropical Atlantic. Of these 50 AEWs, ten to fifteen may develop into tropical storms and half of that number may develop into hurricanes. With an increase in the number and intensity of tropical cyclones in the Atlantic over the past few years, questions have arisen on the effects of the Saharan Air Layer (SAL) and its interaction with tropical cyclogenesis. It is known that when tropical cyclones interact with SAL they have a hard time sustaining development due to a decrease in moisture content, and an overabundance of cloud condensation nuclei (CCN). When tropical cyclones move away from the SAL, rapid intensification has been noted. Numerical simulations using the WRF in concert with the NAMMA data are being conducted to better understand the interaction of AEWs with the SAL For these studies to be useful, a measure of the simulation accuracy is needed. Multiple simulations using different cumulus, boundary layer, and microphysics parameterization schemes were conducted to identify the parameterization schemes necessary to adequately model the development of the tropical cyclones off western Africa. Hurricane Helene was chosen for these simulations because of the wealth of data collected during the NAMMA field campaign in 2006. The goal is to simulate the evolution of Helene from an AEW into a tropical storm and then into hurricane as accurately as possible. This has been done using domains of 36km, 12km, and 4km. The 4km domain has shown to be an important facet of these simulations as it has handled the cumulus parameter much better than the 36km and 12km alone. These simulations will then be used to explore the effects of the SAL on Helene in hopes of gaining a better understanding of this intricate interaction.

  15. Air pressure waves from Mount St. Helens eruptions

    NASA Astrophysics Data System (ADS)

    Reed, Jack W.

    1987-10-01

    Infrasonic recordings of the pressure wave from the Mount St. Helens (MSH) eruption on May 18, 1980, together with the weather station barograph records were used to estimate an equivalent explosion airblast yield for this eruption. Pressure wave amplitudes versus distance patterns were found to be comparable with patterns found for a small-scale nuclear explosion, the Krakatoa eruption, and the Tunguska comet impact, indicating that the MSH wave came from an explosion equivalent of about 5 megatons of TNT. The peculiar audibility pattern reported, with the blast being heard only at ranges beyond about 100 km, is explained by consideration of finite-amplitude shock propagation developments.

  16. 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.

  17. 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.

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

    PubMed

    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-microm 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.

  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.

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. Comparison between Dione' and Helene' surfaces using Cassini VIMS

    NASA Astrophysics Data System (ADS)

    Scipioni, F.; Tosi, F.; Capaccioni, F.; Cerroni, P.; Filacchione, G.; Federico, C.

    2012-04-01

    With 1122 km in diameter, Dione is the second largest inner moon of Saturn. The Voyager spacecrafts observed Dione in 1980 and revealed a complex surface structure. Afterwards, Dione was closely observed by the Cassini-Huygens spacecraft from 2004 to 2011. Dione's surface is composed primarily by water ice with minor abundances of volatiles such as CO2 and CN. The satellite's surface can be divided into some distinct classes: most notably, heavily cratered terrains and less cratered plains. Most of Dione's surface is covered by the heavily cratered terrains, located mainly in the trailing hemisphere and crossed by high-albedo wispy streaks. The origin of the dark material that covers the heavily cratered terrains is still unknown, while wispy units are likely tectonic features. Helene is a Dione's trojan moonlet, which orbits around Saturn in Dione's lagrangian point L4. The Visual and Infrared Mapping Spectrometer (VIMS) instrument onboard the Cassini Orbiter is able to acquire hyperspectral cubes in the overall spectral range from 0.35 to 5.1 μm. We have selected 76 VIMS cubes of Dione in the IR range between 0.85 and 5.1 μm. These data show at the same time a spatial resolution better than 100 km and a good S/N ratio. We have normalized all of the spectra at λ=2.23 μm in order to minimize photometric effects due to different observation conditions. To emphasize the existence of spectral units, we have applied the supervised clustering technique Spectral Angle Mapper (SAM) to the infrared spectra of each cube. A classification method applied to hyperspectral data shows up to be crucial to understand geochemical processes taking place on the icy satellites' surfaces, and, in this particular case, to investigate the possible presence on the surface of Dione of non water-ice materials, such as methane and ammonia. Some classes show also a peculiar trend with respect to the phase angle, possibly related to surface structure. Moreover, the use of this technique

  5. Comparison of Mount Saint Helens Volcanic Eruption to a Nuclear Explosion.

    DTIC Science & Technology

    1981-01-01

    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...Dist v SECTION 1 INTRODUCTION I’ Eruption of steam and ash from Mt . St. Helens in the state of Washing- ton began on 27 March 1980, following a week of...Analysis Center on nuclear weapons effects operated by General Electric-TEMPO, to conduct a quick-look study on the Mt . St. Helens eruptions and their

  6. Deep long-period earthquakes (DLPs) beneath Mount St. Helens

    NASA Astrophysics Data System (ADS)

    Han, J.; Vidale, J. E.; Schmidt, D. A.; Creager, K. C.; Houston, H.

    2015-12-01

    The volcanic deep long-period earthquakes (DLPs) have been observed for a long time but remain poorly understood. Hypotheses associated with magmatic process have been proposed for the mechanisms of these DLPs, including dehydration embrittlement, flow of magma and/or magmatic fluid and cooling of magma. DLPs are commonly characterized by weak signal on the waveforms, deficiency in high-frequency energy, long-duration coda and their rare occurrence. They are located at 10-35 km depth, which are the mid- to lower-crust and/or uppermost mantle. The imaging Magma Under St Helens (iMUSH) experiment began in late June 2014, and since then the broadband seismometers have recorded six DLPs, two of which are also captured by dense array of Nodal stations. We use the iMUSH data and seismic data from nearby network stations to study the DLPs beneath St. Helens. Catalog DLPs are taken as templates to search for repeating events that might be too small to be detected otherwise. So far, we have searched for cross-station correlation detections for four template DLPs for the period 2007 to 2015. Three of the four seems to be isolated one-offs, while the fourth has at least 56 repetitions, three times more than were already in the catalog, and hints of many more. Many of the DLPs have several bursts within tens of seconds or several minutes. Overall the DLPs show an episodic activity with a period of roughly sixteen months. Several, but not all, episodes are temporally correlated with the subduction zone tremor activity west of St. Helens (Figure 1), which we are still investigating. We are locating these detections, and preliminary results suggest concentrated loci within a distance of one or two kilometers. We will conduct correlations between all detections, search farther back in time, and search with other templates as well, to better characterize their timeline and fine-scale geometry and analyze the waveforms to understand their physical mechanisms and the complicated

  7. [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.

  8. SU-C-207B-03: A Geometrical Constrained Chan-Vese Based Tumor Segmentation Scheme for PET

    SciTech Connect

    Chen, L; Zhou, Z; Wang, J

    2016-06-15

    Purpose: Accurate segmentation of tumor in PET is challenging when part of tumor is connected with normal organs/tissues with no difference in intensity. Conventional segmentation methods, such as thresholding or region growing, cannot generate satisfactory results in this case. We proposed a geometrical constrained Chan-Vese based scheme to segment tumor in PET for this special case by considering the similarity between two adjacent slices. Methods: The proposed scheme performs segmentation in a slice-by-slice fashion where an accurate segmentation of one slice is used as the guidance for segmentation of rest slices. For a slice that the tumor is not directly connected to organs/tissues with similar intensity values, a conventional clustering-based segmentation method under user’s guidance is used to obtain an exact tumor contour. This is set as the initial contour and the Chan-Vese algorithm is applied for segmenting the tumor in the next adjacent slice by adding constraints of tumor size, position and shape information. This procedure is repeated until the last slice of PET containing tumor. The proposed geometrical constrained Chan-Vese based algorithm was implemented in Matlab and its performance was tested on several cervical cancer patients where cervix and bladder are connected with similar activity values. The positive predictive values (PPV) are calculated to characterize the segmentation accuracy of the proposed scheme. Results: Tumors were accurately segmented by the proposed method even when they are connected with bladder in the image with no difference in intensity. The average PPVs were 0.9571±0.0355 and 0.9894±0.0271 for 17 slices and 11 slices of PET from two patients, respectively. Conclusion: We have developed a new scheme to segment tumor in PET images for the special case that the tumor is quite similar to or connected to normal organs/tissues in the image. The proposed scheme can provide a reliable way for segmenting tumors.

  9. First record of Puerulus mesodontus Chan, Ma & Chu, 2013 (Crustacea, Decapoda, Achelata, Palinuridae) from south of Java, Indonesia

    PubMed Central

    Hakim, Agus Alim; Mashar, Ali; Butet, Nurlisa Alias; Adrianto, Luky; Farajallah, Achmad

    2016-01-01

    Abstract Background Three specimens of Puerulus mesodontus Chan, Ma & Chu, 2013 (Crustacea, Decapoda, Achelata, Palinuridae) were collected from Palabuhanratu Bay, southern Java, Indonesia. There is no previous record on the presence of the species in Indonesia. This finding represents the first record of this species in Java, Indonesia, and confirms that the species is present in the Indian Ocean. The morphological characters of the species are described. New information This paper contains a new distribution record of a lobster species from Indonesian waters. PMID:27099562

  10. LANDSLIDE DAMMED LAKES AT MOUNT ST. HELENS, WASHINGTON.

    USGS Publications Warehouse

    Meyer, William; Sabol, Martha A.; Schuster, Robert; ,

    1986-01-01

    The collapse of the north face of Mount St. Helens on May 18, 1980, and the debris avalanche that resulted blocked outflow from Spirit Lake and Coldwater and South Fork Castle Creeks. Spirit Lake began to increase in size and lakes began to form in the canyons of Coldwater and South Fork Castle Creeks. Coldwater and Castle Lakes would have overtopped their respective blockages in late 1981 or early 1982. Catastrophic flooding would have occurred from the breakout of Coldwater Lake while serious flooding probably would have resulted from the breakout of Castle Lake. As a result, the level of both lakes was stabilized with spillways in 1981. The three blockages are stable against liquefaction and gravitationally induced slope failure. The existence of groundwater in the blockages was observed in piezometers installed between 1981 and 1983. Groundwater mounds with water levels above lake level exist under the crest of all of the blockages.

  11. 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.

  12. Trajectories of the mount st. Helens eruption plume.

    PubMed

    Danielsen, E F

    1981-02-20

    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 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 x 10(6) cubic kilometers. Only about 1 percent of this volume is attributed to the volcano; the rest was entrained from the environment.

  13. 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.

  14. 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.

  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. 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.

  17. 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.

  18. 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.

  19. Characterization of aerosols from eruptions of mount st. Helens.

    PubMed

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

    1981-02-20

    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.

  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.

  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. Volatiles of Mount St. Helens and their origins

    USGS Publications Warehouse

    Barnes, I.

    1984-01-01

    Analyses have been made of gases in clouds apparently emanating from Mount St. Helens. Despite appearances, most of the water in these clouds does not issue from the volcano. Even directly above a large fumarole ??D and ?? 18O data indicate that only half the water can come from the volcano. Isotopic and chemical evidence also shows the steam in the volcano (-33.0 per mol ??D) from which a condensate of 0.2 N HCI was obtained is not a major cause of the explosions. The steam in the volcano is derived from a metamorphic brine in the underlying Tertiary meta andesite. The gas that caused the explosive eruptions is carbon dioxide. ?? 1984.

  3. Mount St. Helens Project. Cowlitz River Levee Systems, 2009 Level of Flood Protection Update Summary

    DTIC Science & Technology

    2010-02-04

    mountainous region between Mount St. Helens and Mt. Rainier to the Columbia River at Longview, WA. The upstream-most levee is at Castle Rock where a... Mount St. Helens Project Cowlitz River Levee Systems 2009 Level of Flood Protection Update Summary Cowlitz River at Longview...Kelso, Washington February 4, 2010 Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the

  4. Mount St. Helens Long-Term Sediment Management Plan for Flood Risk Reduction

    DTIC Science & Technology

    2010-06-01

    includes three major lakes : Castle, Coldwater, and Spirit (see Figure 1). The area affected by potential flooding varies from bottomland along the...the Mount St. Helens project are described below. a. Spirit Lake Outlet Tunnel . Spirit Lake is located about 5 miles north of Mount St. Helens...see Figure 1). By 1982, water in Spirit Lake was rising dangerously high behind a debris dam left by the eruption. A sudden break in the debris

  5. 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.

  6. 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.

  7. 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.

  8. Observations of volcanic tremor at Mt. St. Helens volcano

    SciTech Connect

    Fehler, M.

    1982-06-25

    Digital recordings of ground motion during tremor episodes accompanying eruptions at Mt. 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 .9 and 1.1 Hz. the relative amplitudes of the two peaks changes between tremor episodes and during single tremor episodes and show 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 path effect of tremor waveforms is small since there are no peaks in the spectra of waveforms recorded during tectonic earthquakes occurring in the vicinity of Mt. St. Helens. Amplitudes of ground motion varies between .11 ..mu..m and 4.7 ..mu..m. Seismic moment rates during the two eruptions are calculated using the model of Aki et al. (1977) and found to vary between 6 x 10/sup 18/ and 1 x 10/sup 20/ dynes cm sec/sup -1/ which are larger than values found by Aki et al. (1977) who studied amplitudes of shallow tremor events recorded during the October, 1963 eruption of Kilauea volcano in Hawaii. 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.

  9. A Chinese chan-based mind-body intervention improves sleep on patients with depression: a randomized controlled trial.

    PubMed

    Chan, Agnes S; Wong, Queenie Y; Sze, Sophia L; Kwong, Patrick P K; Han, Yvonne M Y; Cheung, Mei-chun

    2012-01-01

    Sleep disturbance is a common problem associated with depression, and cognitive-behavioral therapy (CBT) is a more common behavioral intervention for sleep problems. The present study compares the effect of a newly developed Chinese Chan-based intervention, namely Dejian mind-body intervention (DMBI), with the CBT on improving sleep problems of patients with depression. Seventy-five participants diagnosed with major depressive disorder were randomly assigned to receive 10 weekly sessions of CBT or DMBI, or placed on a waitlist. Measurements included ratings by psychiatrists who were blinded to the experimental design, and a standardized questionnaire on sleep quantity and quality was obtained before and after the 10-week intervention. Results indicated that both the CBT and DMBI groups demonstrated significantly reduced sleep onset latency and wake time after sleep onset (effect size range = 0.46-1.0, P ≤ 0.05) as compared to nonsignificant changes in the waitlist group (P > 0.1). Furthermore, the DMBI group, but not the CBT or waitlist groups, demonstrated significantly reduced psychiatrist ratings on overall sleep problems (effect size = 1.0, P = 0.00) and improved total sleep time (effect size = 0.8, P = 0.05) after treatment. The present findings suggest that a Chinese Chan-based mind-body intervention has positive effects on improving sleep in individuals with depression.

  10. A Chinese Chan-Based Mind-Body Intervention Improves Sleep on Patients with Depression: A Randomized Controlled Trial

    PubMed Central

    Chan, Agnes S.; Wong, Queenie Y.; Sze, Sophia L.; Kwong, Patrick P. K.; Han, Yvonne M. Y.; Cheung, Mei-chun

    2012-01-01

    Sleep disturbance is a common problem associated with depression, and cognitive-behavioral therapy (CBT) is a more common behavioral intervention for sleep problems. The present study compares the effect of a newly developed Chinese Chan-based intervention, namely Dejian mind-body intervention (DMBI), with the CBT on improving sleep problems of patients with depression. Seventy-five participants diagnosed with major depressive disorder were randomly assigned to receive 10 weekly sessions of CBT or DMBI, or placed on a waitlist. Measurements included ratings by psychiatrists who were blinded to the experimental design, and a standardized questionnaire on sleep quantity and quality was obtained before and after the 10-week intervention. Results indicated that both the CBT and DMBI groups demonstrated significantly reduced sleep onset latency and wake time after sleep onset (effect size range = 0.46–1.0, P ≤ 0.05) as compared to nonsignificant changes in the waitlist group (P > 0.1). Furthermore, the DMBI group, but not the CBT or waitlist groups, demonstrated significantly reduced psychiatrist ratings on overall sleep problems (effect size = 1.0, P = 0.00) and improved total sleep time (effect size = 0.8, P = 0.05) after treatment. The present findings suggest that a Chinese Chan-based mind-body intervention has positive effects on improving sleep in individuals with depression. PMID:22623888

  11. 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

  12. 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.

  13. 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.

  14. 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

  15. 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.

  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. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Impact on agriculture of the mount st. Helens eruptions.

    PubMed

    Cook, R J; Barron, J C; Papendick, R I; Williams, G J

    1981-01-02

    Ash from Mount St. Helens has fallen over a diverse agricultural area, with deposits of up to 30 kilograms per square meter. Crop losses in eastern Washington are estimated at about $100 million in 1980-about 7 percent of the normal crop value in the affected area and less than was expected initially. Production of wheat, potatoes, and apples will be normal or above normal because the favorable conditions for growth of these crops since the ashfall helped offset the losses. Alfalfa hay was severely lodged under the weight of the ash, but ash-contaminated hay is apparently nontoxic when eaten by livestock. The ash as an abrasive is lethal to certain insects, such as bees and grasshoppers, but populations are recovering. The ash has increased crop production costs by necessitating machinery repairs and increased tillage. On soil, the ash reduces water infiltration, increases surface albedo, and may continue to affect water runoff, erosion, evaporation, and soil temperature even when tilled into the soil. Ash on plant leaves reduced photosynthesis by up to 90 percent. Most plants have tended to shed the ash. With the possible exception of sulfur, the elements in the ash are either unavailable or present in very low concentrations; and no significant contribution to the nutrient status of soils is expected.

  3. 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.

  4. 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.

  5. Volcanic Plume Above Mount St. Helens Detected with GPS

    NASA Astrophysics Data System (ADS)

    Houlié, N.; Briole, P.; Nercessian, A.; Murakami, M.

    2005-07-01

    Eruptions can produce not only flows of incandescent material along the slopes of a volcano but also ash plumes in the troposphere [Sparks et al., 1997] that can threaten aircraft flying in the vicinity [Fisher et al., 1997]. To protect aircraft, passengers, and crews, the International Civil Aviation Organization and the World Meteorological Organization created eight Volcanic Ash Advisory Centers (VAAC, http://www.ssd.noaa.gov/VAAC/vaac.html) around the globe with the goal of tracking volcanic plumes and releasing eruption alerts to airports, pilots, and companies. Currently, the VAAC monitoring system is based mostly on the monitoring systems of any local volcano observatories and on real-time monitoring of data acquired by meteorological satellites. In the case of the 18 August 2000 eruption of the Miyakejima volcano in Japan, Houlié et al. [2005] showed that the Global Positioning System(GPS) might be used as an additional tool for monitoring volcanic plumes. The present article indicates that the 9 March 2005 eruption of Mount St. Helens, Washington, also produced detectable anomalies in GPS data.>

  6. 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.

  7. 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.

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

    USGS Publications Warehouse

    Doukas, Michael P.

    1990-01-01

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

  9. Development of patient-derived xenograft models from a spontaneously immortal low-grade meningioma cell line, KCI-MENG1.

    PubMed

    Michelhaugh, Sharon K; Guastella, Anthony R; Varadarajan, Kaushik; Klinger, Neil V; Parajuli, Prahlad; Ahmad, Aamir; Sethi, Seema; Aboukameel, Amro; Kiousis, Sam; Zitron, Ian M; Ebrahim, Salah A; Polin, Lisa A; Sarkar, Fazlul H; Bollig-Fischer, Aliccia; Mittal, Sandeep

    2015-07-15

    There is a paucity of effective therapies for recurrent/aggressive meningiomas. Establishment of improved in vitro and in vivo meningioma models will facilitate development and testing of novel therapeutic approaches. A primary meningioma cell line was generated from a patient with an olfactory groove meningioma. The cell line was extensively characterized by performing analysis of growth kinetics, immunocytochemistry, telomerase activity, karyotype, and comparative genomic hybridization. Xenograft models using immunocompromised SCID mice were also developed. Histopathology of the patient tumor was consistent with a WHO grade I typical meningioma composed of meningothelial cells, whorls, and occasional psammoma bodies. The original tumor and the early passage primary cells shared the standard immunohistochemical profile consistent with low-grade, good prognosis meningioma. Low passage KCI-MENG1 cells were composed of two cell types with spindle and round morphologies, showed linear growth curve, had very low telomerase activity, and were composed of two distinct unrelated clones on cytogenetic analysis. In contrast, high passage cells were homogeneously round, rapidly growing, had high telomerase activity, and were composed of a single clone with a near triploid karyotype containing 64-66 chromosomes with numerous aberrations. Following subcutaneous and orthotopic transplantation of low passage cells into SCID mice, firm tumors positive for vimentin and progesterone receptor (PR) formed, while subcutaneous implant of high passage cells yielded vimentin-positive, PR-negative tumors, concordant with a high-grade meningioma. Although derived from a benign meningioma specimen, the newly-established spontaneously immortal KCI-MENG1 meningioma cell line can be utilized to generate xenograft tumor models with either low- or high-grade features, dependent on the cell passage number (likely due to the relative abundance of the round, near-triploid cells). These human

  10. Source parameters of microearthquakes at Mount St Helens (USA)

    USGS Publications Warehouse

    Tusa, Giuseppina; Brancato, Alfonso; Gresta, Stefano; Malone, Stephen D.

    2006-01-01

    We estimate the source parameters for a selection of microearthquakes that occurred at Mount St Helens in the period 1995–1998. Excluding the activity of 2004 September, this time period includes the most intense episode of earthquake activity since the last dome-building eruption in 1986 October. 200 seismograms were processed to obtain seismic moments, source radii, stress drops and average fault slip. The source parameters were determined from the spectral analysis of P waves, after correction for attenuation and site effects. In particular, P-wave quality (Qp) and site (S) factors have been previously calculated in the frequency ranges 2–7 Hz and 18–30 Hz. Because it was impossible to perform corrections for Qp and S over the whole spectrum we applied a new approach, based on the notion of ‘holed spectrum’, to estimate spectral parameters. The term ‘holed spectrum’ indicates a spectrum lacking corrected spectral amplitude values at certain frequencies. We carried out a statistical study to verify that dealing with the ‘holed spectrum’ does not lead to significant differences in the estimates of spectral parameters. We also investigated the dependence of spectral parameters (low-frequency level, corner frequency and high-frequency decay) on the bandwidth of spectral hole, and defined the threshold values for three different spectral models. Displacement ‘holed spectra’, corrected by attenuation and site response, are then used to determine spectral parameters in order to calculate seismic source parameters. Seismic moments range from 1017 to 1019 dyne-cm, source dimensions from 100 to 350 m, and average fault slip from 0.003 to 0.1 cm. Self-similarity seems to break down in that stress drops are very low (0.1–1 bars). We postulate that seismicity is associated with a brittle shear failure mechanism occurring in a highly heterogeneous material under a relatively low stress regime.

  11. 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

  12. 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.

  13. 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.

  14. Seismic evidence for a cold serpentinized mantle wedge beneath Mount St Helens

    PubMed Central

    Hansen, S. M.; Schmandt, B.; Levander, A.; Kiser, E.; Vidale, J. E.; Abers, G. A.; Creager, K. C.

    2016-01-01

    Mount St Helens is the most active volcano within the Cascade arc; however, its location is unusual because it lies 50 km west of the main axis of arc volcanism. Subduction zone thermal models indicate that the down-going slab is decoupled from the overriding mantle wedge beneath the forearc, resulting in a cold mantle wedge that is unlikely to generate melt. Consequently, the forearc location of Mount St Helens raises questions regarding the extent of the cold mantle wedge and the source region of melts that are responsible for volcanism. Here using, high-resolution active-source seismic data, we show that Mount St Helens sits atop a sharp lateral boundary in Moho reflectivity. Weak-to-absent PmP reflections to the west are attributed to serpentinite in the mantle-wedge, which requires a cold hydrated mantle wedge beneath Mount St Helens (<∼700 °C). These results suggest that the melt source region lies east towards Mount Adams. PMID:27802263

  15. 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…

  16. EPA Brownfields Grant Will Aid City of St. Helens with Plans to Revitalize Waterfront Area

    EPA Pesticide Factsheets

    (Seattle - March 17, 2015) The City of St. Helens, Oregon has been selected to receive a $200,000 Brownfields Area-Wide Planning (AWP) grant from EPA to help move towards the goal of revitalizing a former industrial property along the Columbia River waterf

  17. An Interview: Helen B. Landgarten, MA, MFCC, A.T.R.-BC, HLM.

    ERIC Educational Resources Information Center

    Warren, Linda A.

    1995-01-01

    An interview with Helen B. Landgarten, a pioneer in art psychotherapy, addresses how she came to work in this field, her training, her experience with Jungian therapy, current approaches to training art therapists, her own painting, and the role of the American Art Therapy Association today. (DB)

  18. 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…

  19. Mt. St. Helens ash in lakes in the Lower Grand Coulee, Washington State

    SciTech Connect

    Edmondson, W.T.; Litt, A.H.

    1983-01-01

    In 1979, an experiment to assess the effects of an introduced predator, cutthroat trout (Salmo clarki henshawi), on the biota of two alkaline lakes, Soap Lake and Lake Lenore, in Washington was initiated. This report discusses the effects of the Mt. St. Helens eruption and associated ash fall on the experiment. (ACR)

  20. Using Microcomputer Game-Simulation Experiments to Study Family Response to Mt. St. Helens Eruptions.

    ERIC Educational Resources Information Center

    Ekker, Knut; And Others

    1988-01-01

    Explains how computerized game-simulation experiments were conducted to ascertain responses to the 1980 eruptions of Mt. St. Helens (Washington). Results indicate different aspects of individual preferences and family decisions with respect to relocation: (1) highly consistent in the game simulation; (2) responsive to the simulated threat; and (3)…

  1. The rule of time and chance: Mount St. Helens and its legacy of knowledge.

    Treesearch

    Sally. Duncan

    2001-01-01

    When Mount St. Helens blew in 1980 it took with it some old ideas that have surprised scientists over the intervening 20 years. Traditional wisdom about ecological succession, survival, and disturbance regimes was moved aside by discoveries of the power of time and chance as environmental agents. Theories about recovery and restoration also have been revised in the...

  2. I Do and I Understand (Glen Helen Workshop: April 29-May 1, 1971).

    ERIC Educational Resources Information Center

    Pinson, Rosie Barajas; And Others

    During the teacher workshop conducted at the Glen Helen Outdoor Education Center at Yellow Springs, Ohio, oral language techniques, Mexican American culture, and outdoor education were given high priority in training teachers to serve migrant children effectively. Four of the workshop presentations have been adapted for this publication. One of…

  3. 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.

  4. 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)

  5. 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.

  6. Seismic evidence for a cold serpentinized mantle wedge beneath Mount St Helens.

    PubMed

    Hansen, S M; Schmandt, B; Levander, A; Kiser, E; Vidale, J E; Abers, G A; Creager, K C

    2016-11-01

    Mount St Helens is the most active volcano within the Cascade arc; however, its location is unusual because it lies 50 km west of the main axis of arc volcanism. Subduction zone thermal models indicate that the down-going slab is decoupled from the overriding mantle wedge beneath the forearc, resulting in a cold mantle wedge that is unlikely to generate melt. Consequently, the forearc location of Mount St Helens raises questions regarding the extent of the cold mantle wedge and the source region of melts that are responsible for volcanism. Here using, high-resolution active-source seismic data, we show that Mount St Helens sits atop a sharp lateral boundary in Moho reflectivity. Weak-to-absent PmP reflections to the west are attributed to serpentinite in the mantle-wedge, which requires a cold hydrated mantle wedge beneath Mount St Helens (<∼700 °C). These results suggest that the melt source region lies east towards Mount Adams.

  7. 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.

  8. 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.

  9. Novel peach flower types in a segregating population from ‘Helen Borchers’

    USDA-ARS?s Scientific Manuscript database

    Several new peach (Prunus persica) flower types were discovered in an F2 segregating population from an open-pollinated, non-showy-flowered F1 seedling of ‘Helen Borchers’, a double-flowered ornamental cultivar. The novel flower types were white and red single-flowered, non-showy blooms, as well as ...

  10. 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…

  11. Could Separate Be Equal? Helene Lange and Women's Education in Imperial Germany.

    ERIC Educational Resources Information Center

    Albisetti, James C.

    1982-01-01

    Helene Lange worked to obtain equal educational opportunities for women in Germany at the end of the nineteenth century. She tried to improve teacher training for women, enhance the curriculum in girls' high schools, and increase professional training opportunities for women. (AM)

  12. Posteruption arthropod succession on the Mount St. Helens volcano: the ground-dwelling beetle fauna (Coleoptera).

    Treesearch

    R.R. Parmenter; C.M. Crisafulli; N. Korbe; G. Parsons; M. Edgar; J.A. MacMahon

    2005-01-01

    The 1980 eruptions of Mount St. Helens created a complex mosaic of disturbance types over a 600 km2 area. From 1980 through 2000 we monitored beetle species relative abundance and faunal composition of assemblages at undisturbed reference sites and in areas subjected to tephra-fall, blowdown, and pyroclastic flow volcanic disturbance. We...

  13. The Larry Jarret House Program at the Helen Beebe Speech and Hearing Center.

    ERIC Educational Resources Information Center

    Goldberg, Donald M.; Talbot, Pamela J.

    1993-01-01

    The Larry Jarret House is a one-week in-residence program of the Helen Beebe Speech and Hearing Center in Easton, Pennsylvania, for parents of children with hearing impairments. The program is designed to help parents maximize their child's use of residual hearing in daily life situations to develop spoken language. (JDD)

  14. Seismic evidence for a cold serpentinized mantle wedge beneath Mount St Helens

    NASA Astrophysics Data System (ADS)

    Hansen, S. M.; Schmandt, B.; Levander, A.; Kiser, E.; Vidale, J. E.; Abers, G. A.; Creager, K. C.

    2016-11-01

    Mount St Helens is the most active volcano within the Cascade arc; however, its location is unusual because it lies 50 km west of the main axis of arc volcanism. Subduction zone thermal models indicate that the down-going slab is decoupled from the overriding mantle wedge beneath the forearc, resulting in a cold mantle wedge that is unlikely to generate melt. Consequently, the forearc location of Mount St Helens raises questions regarding the extent of the cold mantle wedge and the source region of melts that are responsible for volcanism. Here using, high-resolution active-source seismic data, we show that Mount St Helens sits atop a sharp lateral boundary in Moho reflectivity. Weak-to-absent PmP reflections to the west are attributed to serpentinite in the mantle-wedge, which requires a cold hydrated mantle wedge beneath Mount St Helens (<~700 °C). These results suggest that the melt source region lies east towards Mount Adams.

  15. Sediment-discharge characteristics of the Toutle River following the Mount St. Helens eruption

    USGS Publications Warehouse

    Culbertson, J.K.; Dinehart, R.L.

    1982-01-01

    Dinehart, R.L., Culbertson, J.K., 1982, Sediment-discharge characteristics of the Toutle River following the Mount St. Helens eruption, [abs.]: in Proceedings from the Conference on Mount St. Helens— Effects on water resources: State of Washington Water Research Center, p. 149.

  16. 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…

  17. 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.

  18. Rhetoric, Possibility, and Women's Status in Ancient Athens: Gorgias' and Isocrates' Encomiums of Helen.

    ERIC Educational Resources Information Center

    Biesecker, Susan L.

    1992-01-01

    Critiques teleological narrative structures implicit in the work of some classical historians, adopting instead a multilayered historiographical method. Argues that a law instituted in 451/450 B.C.E. by Pericles opened up a possibility for resisting women's exclusion from the public sphere. Reads Gorgias' and Isocrates' speeches on Helen of Troy…

  19. 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.

  20. 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

  1. 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

  2. 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

  3. 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.

  4. An application of Chan-Vese method used to determine the ROI area in CT lung screening

    NASA Astrophysics Data System (ADS)

    Prokop, Paweł; Surtel, Wojciech

    2016-09-01

    The article presents two approaches of determining the ROI area in CT lung screening. First approach is based on a classic method of framing the image in order to determine the ROI by using a MaZda tool. Second approach is based on segmentation of CT images of the lungs and reducing the redundant information from the image. Of the two approaches of an Active Contour, it was decided to choose the Chan-Vese method. In order to determine the effectiveness of the approach, it was performed an analysis of received ROI texture and extraction of textural features. In order to determine the effectiveness of the method, it was performed an analysis of the received ROI textures and extraction of the texture features, by using a Mazda tool. The results were compared and presented in the form of the radar graphs. The second approach proved to be effective and appropriate and consequently it is used for further analysis of CT images, in the computer-aided diagnosis of sarcoidosis.

  5. 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."

  6. Lithium Systematics Revealed in Samples from ODP Leg 204 (Hydrate Ridge): A Tribute to Lui-Heung Chan

    NASA Astrophysics Data System (ADS)

    Torres, M. E.; Chan, L.; Ungerer, A.

    2008-12-01

    Changes in chemical and isotopic composition of interstitial fluids with depth have shown to be powerful tracers of fluid sources and migration patterns, an area of research pioneered by Lui-Heung Chan. It was due to her expertise and passion to unravel key geochemical processes in accretionary margins that we pursued lithium analyses in sediment and pore waters recovered by drilling on Hydrate Ridge during ODP Leg 204. The data reveals several important processes associated with lithium systematics in marine sediments. Specifically: 1) Lithium is consumed at shallow sequences, probably resulting from an interplay of reactions involving alteration of volcanogenic material that occurs simultaneously with release of light lithium from clay sites by exchange with ammonium, as shown previously for the Costa Rica margin. 2) Release of light lithium at depth is consistent with that previously reported in deep sequences of accretionary margins along the Pacific Rim, and likely occurs during clay alteration reactions that precede illitization. 3) An increase in dissolved lithium, associated with anomalously light lithium isotopic composition in a high permeability zone (Horizon A) document migration of aqueous fluids along this horizon, which is thought to act as a methane pathway feeding massive gas hydrate deposits at the seafloor. 4) Analyses of fluids collected from zones of massive hydrate formation at the summit sites reveal that there is no isotopic fractionation of lithium during gas hydrate formation. Lui's life long dedication to precise and accurate measurements of lithium isotopes forms the cornerstone to our understanding of lithium geochemistry and led to important new perspectives on a wide range of natural processes. The rigor of her analytical approaches, the influence of her publications, the patience and dedication to train others and her contagious enthusiasm will be sorely missed. She had a tremendous influence in the personal and professional lives of

  7. Geologic Map of Mount St. Helens, Washington Prior to the 1980 Eruption

    USGS Publications Warehouse

    Hopson, Clifford A.

    2008-01-01

    It is rare that a geologic map exists for a volcano prior to such a catastrophic modification as that produced by the eruption of Mount St. Helens in 1980. As such, this map provides an important historical record of the volcano prior to that eruption. The map has not been reviewed or checked for conformity to USGS editorial standards or stratigraphic nomenclature, and it has not been digitized. This version of the map is unchanged from that submitted to the USGS for publication shortly after the 1980 eruption of Mount St. Helens and includes unresolved inconsistencies with the subsequently published work of Crandell (1987) and Mullineaux (1996). Nevertheless, it is the most accurate available depiction of the pre-1980 edifice and is published here for comparison with more recent geologic mapping and historical perspectives.

  8. 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.

  9. 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.

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

    USGS Publications Warehouse

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

    2005-01-01

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

  11. 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.

  12. 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.

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

    SciTech Connect

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

  14. 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.

  15. Size distributions and mineralogy of ash particles in the stratosphere from eruptions of mount st. Helens.

    PubMed

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

    1981-02-20

    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 in-homogeneity in the eruption clouds.

  16. 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.

  17. 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.

  18. The relationship between Maude Abbott and Helen Taussig: connecting the historical dots.

    PubMed

    Evans, William N

    2008-12-01

    The literature has scant documentation of the relationship between the important founders of paediatric cardiology, Maude Abbott and Helen Taussig. Recently discovered entries in the diaries kept by Maude Abbott provide evidence for a close connection between them. Further evidence suggests that their association was complex, and influenced by outside factors, such as their difference in age and era-related notoriety. In this review, I attempt to define more clearly the relationship between these two early icons of paediatric cardiology.

  19. 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.

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

    USGS Publications Warehouse

    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.

  1. 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.

  2. 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

    1982-02-05

    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.

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. The mount st. Helens volcanic eruption of 18 may 1980: minimal climatic effect.

    PubMed

    Robock, A

    1981-06-19

    An energy-balance numerical climate model was used to simulate the effects of the Mount St. Helens volcanic eruption of 18 May 1980. The resulting surface temperature depression is a maximum of 0.1 degrees C in the winter in the polar region, but is an order of magnitude smaller than the observed natural variability from other effects and will therefore be undetectable.

  10. Measurements of cloud condensation nuclei in the stratosphere around the plume of mount st. Helens.

    PubMed

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

    1981-02-20

    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. 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.

  12. 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.

  13. 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.

  14. Mount st. Helens, washington, 1980 volcanic eruption: magmatic gas component during the first 16 days.

    PubMed

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

    1980-06-13

    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.

  15. 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.

  16. Filter measurements of stratospheric sulfate and chloride in the eruption plume of mount st. Helens.

    PubMed

    Gandrud, B W; Lazrus, A L

    1981-02-20

    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.

  17. Rayleigh wave tomography of Mount St. Helens, Washington from ambient seismic noise

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Lin, F. C.; Farrell, J.; Schmandt, B.

    2015-12-01

    Mount St. Helens is the most active volcano of the Cascade range in the Western U.S. Given its recent eruptions in 1980 and 2005, it is clear that magma transport has recently occurred in the shallow crust beneath the volcanic edifice. A dense seismic array was deployed around Mount St. Helens for two weeks in summer 2014. The array was composed of 904 vertical-component 10-Hz geophones distributed within 20 km of the caldera. We cross-correlated all the seismic ambient noise data from this array to measure Rayleigh wave travel times and invert for the seismic shear velocity structure beneath the volcano. Clear Rayleigh waves are observed between 2 to 5 sec period in most directions and the signal is particularly strong in the Southwest-Northeast direction likely caused by ocean waves off the west coast of Washington State. We applied frequency-time analysis to measure phase velocity dispersions for all available station pairs, and we applied surface wave tomography for each period to determine 2-D Rayleigh wave phase velocity maps between 2 to 5 second period. Finally, we inverted these maps for a preliminary 3D velocity model from surface to 5 km depth. The model shows a low-velocity anomaly beneath the center of the caldera. This anomaly could be related to shallow magma storage beneath Mount St. Helens as well as the highly fractured rock of the volcanic edifice. Further analysis of short period surface wave propagation will improve understanding of upper crustal structure beneath Mount St. Helens and how it is linked to supply of silicate melts and volatiles from greater depths.

  18. 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.

  19. 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.

  20. Trace element composition of the mount st. Helens plume: stratospheric samples from the 18 may eruption.

    PubMed

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

    1981-02-20

    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.

  1. 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.

  2. 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.

  3. Sequence of pumiceous tephra layers and the late quaternary environmental record near mount st. Helens.

    PubMed

    Heusser, C J; Heusser, L E

    1980-11-28

    Tephra in lake beds within 40 kilometers of Mount St. Helens was deposited an average of once every 2,700 years over the past 35,000 years, for a total of 13 layers. Times of deposition span the period of the Fraser Glaciation and intervals before and after it, and include the series of climates prevailing when vegetation west of the Cascade Range shifted between a park-tundra type and the modern western hemlock forest.

  4. 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.

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

    USGS Publications Warehouse

    Pierson, Thomas C.

    1999-01-01

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

  6. VLF electromagnetic investigations of the crater and central dome of Mount St. Helens, Washington

    USGS Publications Warehouse

    Towle, J.N.

    1983-01-01

    A very low frequency (VLF) electromagnetic induction survey in the crater of Mount St. Helens has identified several electrically conductive structures that appear to be associated with thermal anomalies and ground water within the crater. The most interesting of these conductive structures lies beneath the central dome. It is probably a partial melt of dacite similar to that comprising the June 1981 lobe of the central dome. ?? 1983.

  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. 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.

  9. 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.

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

    USGS Publications Warehouse

    Waitt, R.B.; 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.

  11. Mount St. Helens, Washington Feasibility Report & Environmental Impact Statement. Volume 1: Main Report

    DTIC Science & Technology

    1984-12-01

    Council Longview Chamber of Commerce Longview Fibre Company Longview Treatment Plant (Water Dept.) Pacific Northwest Waterways Association Port of...occupancy, repeated clearcut logging and slash treatment , and the effects of the Mount St. Helens ~udflow account for the lack of substantial cultural...prior treatment . e. Aquatic Ecosystem and Organism Determinations. The aquatic ecosystem at the project site was destroyed by the mudflows of the May

  12. 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.

  13. Mount St. Helens: A case study of managing for change in wildland recreation

    NASA Astrophysics Data System (ADS)

    Ewert, Alan

    1990-03-01

    Mount St. Helens provides an interesting case study of a forest and wildland area that has been radically altered in recent history. As a result of volcanic activity, the recreation environment has changed with respect to the setting, climbing opportunities, and motivations for mountaineering. An evaluation process using both qualitative and quantitative methods was developed to determine what the motivations, demographic characteristics, and preferred management techniques were for the posteruption Mount St. Helens mountain-climbing visitor. Results suggest that changes have occurred in the “new” or posteruption climbing visitor. These changes have not all been congruent with those anticipated by management. For example, the climbing visitor is now less interested in climbing opportunities and more concerned with seeing the crater and other volcanic-related features. This article discusses the findings of this research in light of how resource managers might consider the issue of visitor changes in both demands and types of uses. For example, determining quota numbers based on sociological determinants (e.g., desire for solitude) need to be firmly grounded in who the visitors actually are rather than who they were. Consequently, management tools such as the Recreational Opportunity Spectrum (ROS) and Limits of Acceptable Change (LAC) may need to be altered to accommodate a changing resource or visitor base. These and other findings have implications for the future management practices of the Mount St. Helens area and other environments where the recreation resources have undergone rapid and profound change.

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

    NASA Astrophysics Data System (ADS)

    Hill, Graham J.; Caldwell, T. Grant; Heise, Wiebke; Chertkoff, Darren G.; Bibby, Hugh M.; Burgess, Matt K.; Cull, James P.; Cas, Ray A. F.

    2009-11-01

    Three prominent volcanoes that form part of the Cascade mountain range in Washington State (USA)-Mounts St Helens, Adams and Rainier-are located on the margins of a mid-crustal zone of high electrical conductivity. Interconnected melt can increase the bulk conductivity of the region containing the melt, 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 this volcano 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 Helens, and explains the distribution of seismicity observed at the time of the catastrophic eruption in 1980 (refs 9, 10).

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Holocene geomagnetic secular variation recorded by volcanic deposits at Mount St. Helens, Washington

    USGS Publications Warehouse

    Hagstrum, J.T.; Hoblitt, R.P.; Gardner, C.A.; Gray, T.E.

    2002-01-01

    A compilation of paleomagnetic data from volcanic deposits of Mount St. Helens is presented in this report. The database is used to determine signature paleomagnetic directions of products from its Holocene eruptive events, to assign sampled units to their proper eruptive period, and to begin the assembly of a much larger database of paleomagnetic directions from Holocene volcanic rocks in western North America. The paleomagnetic results from Mount St. Helens are mostly of high quality, and generally agree with the division of its volcanic deposits into eruptive episodes based on previous geologic mapping and radiocarbon dates. The Muddy River andesite's paleomagnetic direction, however, indicates that it is more likely part of the Pine Creek eruptive period rather than the Castle Creek period. In addition, the Two-Fingers andesite flow is more likely part of the Middle Kalama eruptive period and not part of the Goat Rocks period. The paleomagnetic data from Mount St. Helens and Mount Hood document variation in the geomagnetic field's pole position over the last ~2,500 years. A distinct feature of the new paleosecular variation (PSV) record, similar to the Fish Lake record (Oregon), indicates a sudden change from rapid clockwise movement of the pole about the Earth's spin axis to relatively slow counterclockwise movement at ???800 to 900 years B.P.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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)

  7. A Randomized Controlled Neurophysiological Study of a Chinese Chan-Based Mind-Body Intervention in Patients with Major Depressive Disorder

    PubMed Central

    Chan, Agnes S.; Han, Yvonne M. Y.; Sze, Sophia L.; Wong, Queenie Y.

    2013-01-01

    Our previous studies have reported the therapeutic effects of 10-session Chinese Chan-based Dejian mind-body interventions (DMBI) in reducing the intake of antidepressants, improving depressive symptoms, and enhancing the attentional abilities of patients with depression. This study aims to explore the possible neuroelectrophysiological mechanisms underlying the previously reported treatment effects of DMBI in comparison with those of cognitive behavioral therapy (CBT). Seventy-five age-, gender-, and education-matched participants with depression were randomly assigned to receive either CBT or DMBI or placed on a waitlist. Eyes-closed resting EEG data were obtained individually before and after 10 weeks. After intervention, the DMBI group demonstrated significantly enhanced frontal alpha asymmetry (an index of positive mood) and intra- and interhemispheric theta coherence in frontoposterior and posterior brain regions (an index of attention). In contrast, neither the CBT nor the waitlist group showed significant changes in EEG activity patterns. Furthermore, the asymmetry and coherence indices of the DMBI group were correlated with self-reported depression severity levels and performance on an attention test, respectively. The present findings provide support for the effects of a Chinese Chan-based mind-body intervention in fostering human brain states that can facilitate positive mood and an attentive mind. PMID:24489591

  8. Lidar observations of the Mount St. Helens eruption clouds over mid-Europe, May to July 1980

    NASA Astrophysics Data System (ADS)

    Reiter, R.; Jaeger, H.; Carnuth, W.; Funk, W.

    1980-12-01

    Three violent eruptions of the Mount St. Helens volcano on 18 and 24 May and 13 June terminated the period of background aerosol prevailing in the stratosphere since the end of 1976, after the decay of the volcanic aerosols injected by the Fuego eruption in 1974. The Mt. St. Helens eruption cloud arrived over mid-Europe on 26 May. The subsequent formation of a multi-layered aerosol structure between 12 and 24 km could be observed by the ground-based lidar at Garmisch-Partenkirchen. The highest altitude of 24 km was reached on 30 June, the maximum scattering ratio of 4.8 at 21 km on 14 July. The scattering ratios observed indicate that the St. Helens eruption is comparable to that of Fuego in 1974.

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

    USGS Publications Warehouse

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

    2008-01-01

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

  10. 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.

  11. Systematic detection of seismic events at Mount St. Helens with an ultra-dense array

    NASA Astrophysics Data System (ADS)

    Meng, X.; Hartog, J. R.; Schmandt, B.; Hotovec-Ellis, A. J.; Hansen, S. M.; Vidale, J. E.; Vanderplas, J.

    2016-12-01

    During the summer of 2014, an ultra-dense array of 900 geophones was deployed around the crater of Mount St. Helens and continuously operated for 15 days. This dataset provides us an unprecedented opportunity to systematically detect seismic events around an active volcano and study their underlying mechanisms. We use a waveform-based matched filter technique to detect seismic events from this dataset. Due to the large volume of continuous data ( 1 TB), we performed the detection on the GPU cluster Stampede (https://www.tacc.utexas.edu/systems/stampede). We build a suite of template events from three catalogs: 1) the standard Pacific Northwest Seismic Network (PNSN) catalog (45 events); 2) the catalog from Hansen&Schmandt (2015) obtained with a reverse-time imaging method (212 events); and 3) the catalog identified with a matched filter technique using the PNSN permanent stations (190 events). By searching for template matches in the ultra-dense array, we find 2237 events. We then calibrate precise relative magnitudes for template and detected events, using a principal component fit to measure waveform amplitude ratios. The magnitude of completeness and b-value of the detected catalog is -0.5 and 1.1, respectively. Our detected catalog shows several intensive swarms, which are likely driven by fluid pressure transients in conduits or slip transients on faults underneath the volcano. We are currently relocating the detected catalog with HypoDD and measuring the seismic velocity changes at Mount St. Helens using the coda wave interferometry of detected repeating earthquakes. The accurate temporal-spatial migration pattern of seismicity and seismic property changes should shed light on the physical processes beneath Mount St. Helens.

  12. 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.

  13. ICT Action School Development at Helen Parkhurst Dalton School, Part II

    NASA Astrophysics Data System (ADS)

    Hogenbirk, Pieter; van de Braak, Peter

    The paper presents the progress of the action plan for improvement of the ICT usage at the Helen Parkhurst Dalton School for secondary education. At the start of the described action period in 2007 the ICT-usage in education was assessed through an review performed by a group of European inspectors. This assessment formed the basis for a continuous development in the school for promoting and improving the usage of ICT. This was done by addressing the observed weaknesses with special measures, and continuing the action plans which were already put in place. For four main points of criticism the following measures were taken.

  14. Overview of the tectonic setting and recent studies of eruptions of Mount St. Helens, Washington

    NASA Astrophysics Data System (ADS)

    Weaver, Craig S.; Malone, Stephen D.

    1987-09-01

    Mount St. Helens lies along the western front of the Cascade Range between Mount Rainier, Washington, and Mount Hood, Oregon. This is an area of transition, both geologically and geophysically. North of Mount Rainier, late Cenozoic volcanism is limited to the major stratovolcanoes, whereas south of Mount Hood the volcanic cover from both stratovolcanoes and monogenetic vents is nearly continuous for 300 km. The dominant stratovolcanoes in the southern Washington Cascade Range are physio-graphically similar to those in the North Cascades, but the volcanic cover is similar to the Oregon Cascades. A saddle occurs in the Bouguer gravity data over the Columbia River, interrupting a west-east gravity gradient observed along the rest of the Oregon Cascade Range. Heat flow values are intermediate, being lower than those observed in Oregon but higher than those observed north of Mount Rainier. Seismicity is mostly concentrated along the St. Helens zone (SHZ), and all crustal earthquakes greater than magnitude 5 since 1960 in Washington and northern Oregon have occurred between Mount Rainier and Mount Hood. Little seismicity is known within the Cascade Range south of Mount Hood, and few earthquakes occur within the North Cascades of Washington. Magnetotelluric studies indicate a conductor within the area bounded by Mount Rainier, Mount Adams, and Mount St. Helens, and the conductor is interpreted as an east dipping, compressed marine terrain in the upper plate. Mount St. Helens is located at a dextral offset in the SHZ where the SHZ intersects a set of older, mapped fractures that are preferentially aligned with the contemporary regional principal stress direction. Aeromagnetic and gravity data suggest the presence of an intrusive body beneath the volcano; petrogenesis studies favor multiple intrusions of small batches of magma into the shallow volcanic system. Studies of pyroclastic flows indicate that turbulence within the head of pyroclastic flows may be important for the

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Changes in stratospheric water vapor associated with the mount st. Helens eruption.

    PubMed

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

    1981-02-20

    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(-6). This compares with values of 2 x 10(-6) to 3 x 10(-6) outside of the plume.

  5. Airborne studies of the emissions from the volcanic eruptions of mount st. Helens.

    PubMed

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

    1981-02-20

    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 nuées ardentes, lightning flashes, and volcanic hail.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

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

    PubMed

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

    1982-04-09

    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.

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

    PubMed

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

    1982-04-09

    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.

  14. Measurements of the stratospheric plume from the Mount St. Helens eruption - Radioactivity and chemical composition

    NASA Astrophysics Data System (ADS)

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

    1981-11-01

    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 to the 3rd in the stratospheric number concentration of submicrometer sulfate particles compared to concentrations before the eruption.

  15. 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.

  16. 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.

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

    NASA Astrophysics Data System (ADS)

    Nathenson, M.

    2015-12-01

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

  18. 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. 

  19. Particle geochemistry of volcanic plumes of Etna and Mount St. Helens

    NASA Astrophysics Data System (ADS)

    Varekamp, Johan C.; Thomas, Ellen; Germani, Mark; Buseck, Peter R.

    1986-11-01

    Particles in volcanic plumes include vapor condensates and reaction products of ash with vapors or condensed liquids, in addition to abundant silicate particles. In the 1980 Mount St. Helens plume we detected abundant (Na, K) Cl crystals as well as Ca sulfates, the latter commonly as overgrowths on ash or anthropogenic particles. Many of the chloride particles contained zinc and cadmium. High-temperature fumarolic incrustations showed strong enrichments of arsenic, zinc, alkalis, and iron. At Etna we did not detect chloride crystals but found abundant Al, Fe, and Ca sulfates. Sulfuric acid droplets were ubiquitous in both plumes. Bulk analyses of fumarole incrustations at Etna showed an enrichment in the rare earth elements (REE). The chemical and textural data of the plume particles indicate that chloride particles form relatively early and react later with sulfuric acid droplets to form sulfates. At Etna, aluminum as well as some REE are probably transported as volatile fluorine compounds. The differences in plume chemistry between Etna and Mount St. Helens are most likely related to differences in F/Cl ratios of the vapors. Based on the abundance of particulate chlorine in plumes, we suggest that only a small fraction of the total chlorine released during an eruption might reach the stratosphere in the vapor phase.

  20. Precipitation Data for the Mount St. Helens Area, Washington--1981-86

    USGS Publications Warehouse

    Uhrich, Mark A.

    1990-01-01

    This report is a compilation of precipitation data from U.S. Geological Survey telemetered 'Early Flood Warning' sites near Mount St. Helens, Washington, and from telemetered hydrologic data sites in the Toutle River and Muddy River basins for the years 1981-86. It also includes precipitation data for 1981-86 from non-telemetered recording rain gages established near the debris-avalanche blockages of Spirit Lake, Coldwater Lake, and Castle Lake. Daily values (midnight to midnight) are listed by station and calendar year for 32 sites. Hourly data, where available, are presented for the storm that generated the highest peak discharge in the North Fork Toutle River each water year. Instrumentation includes 25 tipping-bucket, and 7 weighing-bucket rain gages all without windshields. The seven sites with weighing-bucket gages were the only U.S. Geological Survey sites at which snowfall was measured. Additional snowfall measurements for the same time period in the Mount St. Helens area were collected by the National Weather Service, the U.s. Soil Conservation Service, and the U.S. Army Corps of Engineers and also are presented in this report.

  1. Legionella sainthelensi: a new species of Legionella isolated from water near Mt. St. Helens.

    PubMed Central

    Campbell, J; Bibb, W F; Lambert, M A; Eng, S; Steigerwalt, A G; Allard, J; Moss, C W; Brenner, D J

    1984-01-01

    Six strains of a new species, Legionella sainthelensi, were isolated from freshwater in areas affected by the volcanic eruptions of Mt. St. Helens in the state of Washington. Strains of L. sainthelensi are culturally and biochemically similar to other legionellae. They grow on buffered charcoal yeast agar but not on media that lack cysteine. They are gram-negative, nonsporeforming, motile rods that are positive in reactions for catalase, oxidase, gelatin liquefaction, and beta-lactamase. They are negative in reactions for urease, hydrolysis of hippurate, reduction of nitrates, fermentation of glucose, and blue-white autofluorescence. Their cell wall fatty acid composition is qualitatively similar to those of other legionellae, with 50 to 62% branched-chain fatty acids. They contain the isobranched-chain 14- and 16-carbon acids and anteisobranched-chain 15- and 17-carbon acids and relatively large amounts of straight-chain 16-carbon acid. All strains of L. sainthelensi contain approximately equal amounts of ubiquinones Q9, Q10, Q11, and Q12, a pattern similar to those of Legionella bozemanii, Legionella dumoffi, and Legionella longbeachae. Serological cross-reactions were observed between L. sainthelensi, both serogroups of L. longbeachae, and Legionella oakridgensis. Three strains of L. sainthelensi were greater than 90% related by DNA hybridization. The type strain of L. sainthelensi, Mt. St. Helens 4, was 36% related to the type strain of L. longbeachae and 3 to 14% related to the other nine described Legionella species. PMID:6712210

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Water fact sheet; evolution of sediment yield from Mount St. Helens, Washington, 1980-1993

    USGS Publications Warehouse

    Costa, John E.

    1994-01-01

    The most enduring geological consequence of the eruption of Mount St. Helens, Washington, on May 18, 1980, and the most costly single element in the recovery effort, has been the persistent downstream sedimentation caused by erosion of the approximately 3 cubic kilometers (km3) of sediment deposited on the landscape surrounding the volcano. Most of the sediment was associated with the emplacement of a 2.8 km3 debris avalanche in the upper part of the watershed of the North Fork Toutle River, and debris flows in the channels of the South Fork Toutle River, Pine Creek, Swift Creek, and Muddy River. An additional 0.2-0.3 km3 of volcanic material was emplaced by pyroclastic flows, blasts, and ash fall. Part of this vast quantity of volcaniclastic sediment has been subsequently eroded by runoff and streamflow. This brief report summarizes the changes in sediment yield at five locations around Mount St. Helens in the first 13 years following the May 18, 1980 eruption.

  7. 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.

  8. 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.

  9. 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)

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

    USGS Publications Warehouse

    Crandell, Dwight Raymond; Mullineaux, Donal Ray

    1978-01-01

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

  11. Source mechanism of the May 18, 1980, Mount St. Helens eruption from regional surface waves

    NASA Astrophysics Data System (ADS)

    Burger, Roy W.; Langston, Charles A.

    1985-08-01

    A reference source equalization method using regional surface waves from the Mount St. Helens eruption of May 18, 1980, and the Elk Lake event of February 14, 1981, was used to determine the St. Helens eruption source time history. The time domain deconvolution signals display a complex series of pulses lasting 250 s. An initial pulse was isolated and was found to have a smoothly varying two-lobed radiation pattern for both Love and Rayleigh waves, suggesting a near-horizontal point force directed south consistent with previous results. The initial southward force corresponds to the acceleration of the landslide in a northern direction about 5-10 s after the triggering earthquake. Lateral forces were isolated 70-140 s later, consistent with the occurrence of the large lateral blast and the slide changing its direction down the Toutle River Valley. There also appears to be significant source activity between 140 and 250 s after the initial pulse. This later activity exhibits forces in the northwest-southeast azimuth and may correspond to the final deceleration of the landslide. Several vertical pulses were located between 10-60 and 100-120 s after the eruption began. Much of the vertical force represents the two sets of explosions which occurred during the eruption.

  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. Genetic structure among coastal tailed frog populations of Mount St. Helens is moderated by post-disturbance management

    Treesearch

    Stephen F. Spear; Charles M. Crisafulli; Andrew. Storfer

    2012-01-01

    Catastrophic disturbances often provide “natural laboratories” that allow for greater understanding of ecological processes and response of natural populations. The 1980 eruption of the Mount St. Helens volcano in Washington, USA, provided a unique opportunity to test biotic effects of a large-scale stochastic disturbance, as well as the influence of post-disturbance...

  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. 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)

  16. Mount St. Helens: biological responses following the 1980 eruptions — an indexed bibliography and research abstracts (1980 - 93).

    Treesearch

    Peter M. Frenzen; Anne M. Delano

    1994-01-01

    The May 18, 1980, eruption of Mount St. Helens in Washington is possibly the best documented geological event in history. The bibliography displays the results of 13 years of biological and related research in a convenient, indexed format. Our intent is to facilitate collaboration between scientists contemplating new research initiatives and experienced investigators...

  17. Educating Black Girls in the Early 20th Century: The Pioneering Work of Nannie Helen Burroughs (1879-1961)

    ERIC Educational Resources Information Center

    Bair, Sarah D.

    2008-01-01

    Using social education as a theoretical framework, this article examines the educational theories of Nannie Helen Burroughs (1883-1961), founder of the National Training School for Women and Girls in 1909, and discusses the social studies curriculum at her school. Burroughs's papers reveal her efforts to build a curriculum that blended practical,…

  18. 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)…

  19. Mount St. Helens ash and mud: Chemical properties and effects on germination and establishment of trees and browse plants.

    Treesearch

    M.A. Radwan; Dan L. Campbell

    1981-01-01

    Chemical properties of ash and mud from the 1980 volcanic eruption of Mount St. Helens and their effect on germination and seedling production of selected plants were studied. The volcanic materials were low in some important nutrients and cation exchange capacity, and they adversely affected seedling production. Catsear, a preferred wildlife browse, and lodgepole pine...

  20. 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…

  1. 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.

  2. Shear Velocity Structure of the Mount St. Helens Region from the iMUSH array

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

    The imaging Magma Under Mount St. Helens (iMUSH) experiment was designed to illuminate the deep magmatic plumbing system of this arc volcano. The 70-element iMUSH broadband array was deployed for 2 years with 10 km station spacing and a 100 km aperture. We image shear velocity structure using ambient noise tomography (ANT). Rayleigh wave phase velocities at 0.05 to 0.18 Hz are calculated from cross correlations of ambient noise on vertical channels for seismic station pairs. The minimum resolvable wavelength ranges from 33 km at 0.18 Hz to 60 km at 0.05 Hz, with sensitivity throughout the crust and uppermost mantle. Phase velocity maps show a high velocity zone beneath and west of Mount St Helens (MSH) and a low velocity zone beneath Mount Adams, 50 km east, at all frequencies. Beamforming of background noise in subarrays confirms the absolute phase velocities determined by ANT and overall E-W trends, within 0.15 km/s. The ANT phase velocity maps are inverted for shear velocities (Vs) at each 0.1 by 0.1 degree map pixel. At 0-5 km depth a low velocity feature is imaged several tens of km NW of MSH. It lies adjacent to the northwestern portion of the St. Helens seismic zone, and to sediments just west of the ancestral Cascades. Crust at 10-30 km depth has high Vs (> 3.8 km/s) west of MSH and lower Vs (< 3.5 km/s) to the east with the boundary directly beneath MSH and the lowest Vs beneath Mount Adams. At mantle depths this pattern reverses, and Vs is around 4.2 km/s beneath and west of MSH compared to >4.6 km/s to the east. The crustal velocity pattern resembles that expected of crustal temperature variations between the cold forearc and hot volcanic crust. Furthermore, the faster velocities west of MSH may delineate the mafic Siletzia terrane, whose eastern extent is unclear. Lower velocities NE of MSH correlate with the southern Washington Cascades electromagnetic conductor, suggesting a common origin. In the upper mantle, lower velocities west of MSH are

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

    NASA Astrophysics Data System (ADS)

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

    2004-08-01

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

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

    USGS Publications Warehouse

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

    2008-01-01

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

  5. 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.

  6. 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.

  7. Petrologic monitoring of 1981 and 1982 eruptive products from Mount St. Helens

    USGS Publications Warehouse

    Cashman, K.V.; Taggart, J.E.

    1983-01-01

    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.

  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. 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.

  10. 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.

  11. 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.

  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. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2008-10-01

    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.

  15. Didymus the blind: an unknown precursor of Louis Braille and Helen Keller.

    PubMed

    Lascaratos, J; Marketos, S

    1994-01-01

    The present study presents the case of Didymus the Blind, worthy author, philosopher and theologian of the 4th century AD. Blinded by ophthalmia at the age of four years, Didymus succeeded in achieving great learning in the philosophical and natural sciences. He began his education by using a system which was remarkably like Braille, that is reading letters engraved into the surface of wood by touch and subsequently furthering his knowledge by listening. This learning process of Didymus the Blind appears as the precursor of Louis Braille who invented the educational system of reading embossed dots by touch. Like Didymus, Braille lost his vision in infancy (at three years of age). Another parallel of Didymus' career and written works is found in the example and achievements of Helen Keller.

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

    NASA Astrophysics Data System (ADS)

    Walter, Thomas R.

    2011-08-01

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

  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. 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.

  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. 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.

  1. Atmospheric oscillations after the May 18, 1980 eruption of Mount St. Helens

    NASA Astrophysics Data System (ADS)

    Bolt, Bruce A.; Tanimoto, Toshiro

    Air waves corresponding both to direct (A1) and antipodean (A2) travel paths were clearly recorded on a sensitive microbarograph at Berkeley after the violent eruption of Mount St. Helens on May 18, 1980 (see Figure 1). These unusual complementary recordings throw light on the acoustic energy released as compared with Krakatoa [Strachey, 1888], atmospheric oscillations and their attenuation, and the directive properties of the phreatic blast. The principal explosive eruptions followed closely on an earthquake, Richter magnitude 4.9, origin time 1532 GMT, centered near the volcano. Atmospheric waves and associated magnetic perturbations [Fougere and Tsacoyeanes, 1980] from these eruptions were recorded by microbarographs, seismographs, and magnetometers around the world. In particular, Ritsema [1980] has published records of the A1 atmospheric wave train and the A2 wave (called B1 by him) recorded at De Bilt, Holland. The A2 waves at De Bilt, however, are barely visible on the paper record.

  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. 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.

  4. 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.

  5. 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.

  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.

  7. 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.

  8. 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.

  9. 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.

  10. Gaseous constituents in the plume from eruptions of mount st. Helens.

    PubMed

    Inn, E C; Vedder, J F; Condon, E P; O'hara, D

    1981-02-20

    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.

  11. 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.

  12. 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.

  13. 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.

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

    USGS Publications Warehouse

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

    2010-01-01

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

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

    USGS Publications Warehouse

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

    1989-01-01

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

  16. 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.

  17. 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.

  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. Attenuation and scattering tomography of the deep plumbing system of Mount St. Helens

    USGS Publications Warehouse

    De Siena, Luca; Thomas, Christine; Waite, Greg P.; Moran, Seth C.; Klemme, Stefan

    2014-01-01

    We present a combined 3-D P wave attenuation, 2-D S coda attenuation, and 3-D 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 deeper aseismic velocity anomalies. Both the volcanic edifice and these structures induce a combination of strong scattering and attenuation on any seismic wavefield, 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 3-D 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 northeastern 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 nonstandard tomographic methods, leading toward full-waveform tomography, represent the future of seismic volcano imaging.

  20. Vapor transfer prior to the October 2004 eruption of Mount St. Helens, Washington

    USGS Publications Warehouse

    Kent, A.J.R.; Blundy, J.; Cashman, K.V.; Copper, K.M.; Donnelly, C.; Pallister, J.S.; Reagan, M.; Rowe, M.C.; Thornber, C.R.

    2007-01-01

    Dome lavas from the 2004 eruption of Mount St. Helens show elevated Li contents in plagioclase phenocrysts at the onset of dome growth in October 2004. These cannot be explained by variations in plagioclase-melt partitioning, but require elevated Li contents in coexisting melt, a fact confirmed by measurements of Li contents as high as 207 ??g/g in coexisting melt inclusions. Similar Li enrichment has been observed in material erupted prior to and during the climactic May 1980 eruption, and is likewise best explained via pre-eruptive transfer of an exsolved alkali-rich vapor phase derived from deeper within the magma transport system. Unlike 1980, however, high Li samples from 2004 show no evidence of excess (210Pb)/(226 Ra), implying that measurable Li enrichments may occur despite significant differences in the timing and/or extent of magmatic degassing. Diffusion modeling shows that Li enrichment occurred within -1 yr before eruption, and that magma remained Li enriched until immediately before eruption and cooling. This short flux time and the very high Li contents in ash produced by phreatomagmatic activity prior to the onset of dome extrusion suggest that vapor transfer and accumulation were associated with initiation of the current eruption. Overall, observation of a high Li signature in both 1980 and 2004 dacites indicates that Li enrichment may be a relatively common phenomenon, and may prove useful for petrologic monitoring of Mount St. Helens and other silicic volcanoes. Lithium diffusion is also sufficiently rapid to constrain vapor transfer on similar time scales to short-lived radionuclides. ?? 2007 Geological Society of America.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Attenuation and scattering tomography of the deep plumbing system of Mount St. Helens

    NASA Astrophysics Data System (ADS)

    De Siena, Luca; Waite, Greg; Moran, Seth; Klemme, Stephan; Thomas, Christine

    2014-05-01

    We present a combined 3D P-wave attenuation, 2D S-coda attenuation, and 3D S-coda scattering tomography model of magmatic/fluid chambers, 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 cumulates within and below the volcanic edifice down to 6 km depth. These structures induce a combination of resonant-scattering and strong attenuation on any seismic wave-field recorded north and east 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 inferred to lie within the Saint Helens Seismic Zone (SHZ). 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 larger than 6 km at MSH. The images suggest a small north-east shift in the lower plumbing system of the volcano as well as the absence of any large melt sill extending between depths of 0 and 18 km. 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.

  7. Attenuation and scattering tomography of the deep plumbing system of Mount St. Helens

    NASA Astrophysics Data System (ADS)

    De Siena, Luca; Thomas, Christine; Waite, Greg; Moran, Seth; Klemme, Stephan

    2015-04-01

    We present a combined 3-D P wave attenuation, 2-D S coda attenuation, and 3-D 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 deeper aseismic velocity anomalies. Both the volcanic edifice and these structures induce a combination of strong scattering and attenuation on any seismic wavefield, 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 3-D 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 northeastern 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 nonstandard tomographic methods, leading toward full-waveform tomography, represent the future of seismic volcano imaging.

  8. 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.

    2014-11-01

    We present a combined 3-D P wave attenuation, 2-D S coda attenuation, and 3-D 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 deeper aseismic velocity anomalies. Both the volcanic edifice and these structures induce a combination of strong scattering and attenuation on any seismic wavefield, 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 3-D 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 northeastern 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 nonstandard tomographic methods, leading toward full-waveform tomography, represent the future of seismic volcano imaging.

  9. Magma Intrusion at Mount St. Helens, Washington, from Temporal Gravity Variations

    NASA Astrophysics Data System (ADS)

    Battaglia, Maurizio; Lisowski, Mike; Dzursin, Dan; Poland, Mike; Schilling, Steve; Diefenbach, Angie; Wynn, Jeff

    2017-04-01

    Mount St. Helens is a stratovolcano in the Pacific Northwest region of the United States, best known for its explosive eruption in May 1980 - deadliest and most economically destructive volcanic event in US history. Volcanic activity renewed in September 2004 with a dome forming eruption that lasted until 2008. This eruption was surprising because the preceding four years had seen the fewest earthquakes and no significant deformation since the 1980-86 eruption ended. After the dome forming eruption ended in July 2008, the volcano seismic activity and deformation went back to background values. Time-dependent gravimetric measurements can detect subsurface processes long before magma flow leads to earthquakes or other eruption precursors. A high-precision gravity monitoring network (referenced to a base station 36 km NW of the volcano) was set up at Mount St Helens in 2010. Measurements were made at 12 sites on the volcano (at altitudes between 1200 and 2350 m a.s.l.) and 4 sites far afield during the summers of 2010, 2012, and 2014. The repeated gravity measurements revealed an increase in gravity between 2010 and 2014. Positive residual gravity anomalies remained after accounting for changes in surface height, in the Crater Glacier, and in the shallow hydrothermal aquifer. The pattern of residual gravity changes, with a maximum of 57±12 μGal from 2010 to 2014, is radially symmetric and centered on the 2004-08 lava dome. Inversion of the residual gravity signal points to a source 2.5-4 km beneath the crater floor (i.e., in the magma conduit that fed eruptions in 1980-86 and 2004-08). We attribute the gravity increase to re-inflation of the magma plumbing system following the 2004-8 eruption. Recent seismic activity (e.g., the seismic swarm of March 2016) has been interpreted as a response to the slow recharging of the volcano magma chamber.

  10. 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).

  11. Catalog of Mount St. Helens 2004-2007 Dome Samples with Major- and Trace-Element Chemistry

    USGS Publications Warehouse

    Thornber, Carl R.; Pallister, John S.; Rowe, Michael C.; McConnell, Siobhan; Herriott, Trystan M.; Eckberg, Alison; Stokes, Winston C.; Cornelius, Diane Johnson; Conrey, Richard M.; Hannah, Tammy; Taggart, Joseph E.; Adams, Monique; Lamothe, Paul J.; Budahn, James R.; Knaack, Charles M.

    2008-01-01

    Sampling and analysis of eruptive products at Mount St. Helens is an integral part of volcano monitoring efforts conducted by the U.S. Geological Survey?s Cascades Volcano Observatory (CVO). The objective of our eruption sampling program is to enable petrological assessments of pre-eruptive magmatic conditions, critical for ascertaining mechanisms for eruption triggering and forecasting potential changes in eruption behavior. This report provides a catalog of near-vent lithic debris and new dome-lava collected during 34 intra-crater sampling forays throughout the October 2004 to October 2007 (2004?7) eruptive interval at Mount St. Helens. In addition, we present comprehensive bulk-rock geochemistry for a time-series of representative (2004?7) eruption products. This data, along with that in a companion report on Mount St. Helens 2004 to 2006 tephra by Rowe and others (2008), are presented in support of the contents of the U.S. Geological Survey Professional Paper 1750 (Sherrod and others, eds., 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. The suite of rock samples related to the 2004?7 eruption of Mount St. Helens and presented in this catalog are archived at the David A. Johnson Cascades Volcano Observatory, Vancouver, Wash. The Mount St. Helens 2004?7 Dome Sample Catalogue with major- and trace-element geochemistry is tabulated in 3 worksheets of the accompanying Microsoft Excel file, of2008-1130.xls. Table 1 provides location and sampling information. Table 2 presents sample descriptions. In table 3, bulk-rock major and trace-element geochemistry is listed for 44 eruption-related samples with intra-laboratory replicate analyses of 19 dacite lava samples. A brief overview of the collection methods and lithology of dome samples is given below as an aid to deciphering the dome sample

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

    USGS Publications Warehouse

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

    2008-01-01

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

  13. Ambient airborne solids concentrations including volcanic ash at Hanford, Washington sampling sites subsequent to the Mount St. Helens eruption

    NASA Technical Reports Server (NTRS)

    Sehmel, G. A.

    1982-01-01

    Airborne solids concentrations were measured on a near daily basis at two Hanford, Washington sites after the eruption of Mount St. Helens on May 18, 1980. These sites are about 211 km east of Mount St. Helens. Collected airborne solids included resuspended volcanic ash plus normal ambient solids. Average airborne solids concentrations were greater at the Hanford meteorological station sampling site which is 24 km northwest of the Horn Rapids dam sampling site. These increased concentrations reflect the sampling site proximity to greater ash fallout depths. Both sites are in low ash fallout areas although the Hanford meteorological station site is closer to the greater ash fallout areas. Airborne solids concentrations were decreased by rain, but airborne solids concentrations rapidly increased as surfaces dried. Airborne concentrations tended to become nearly the same at both sampling sites only for July 12 and 13.

  14. Multiphase-flow numerical modeling of the 18 May 1980 lateral blast at Mount St. Helens, USA

    USGS Publications Warehouse

    Ongaro, T.E.; Widiwijayanti, C.; Clarke, A.B.; Voight, B.; Neri, A.

    2011-01-01

    Volcanic lateral blasts are among the most spectacular and devastating of natural phenomena, but their dynamics are still poorly understood. Here we investigate the best documented and most controversial blast at Mount St. Helens (Washington State, United States), on 18 May 1980. By means of three-dimensional multiphase numerical simulations we demonstrate that the blast front propagation, fi nal runout, and damage can be explained by the emplacement of an unsteady, stratifi ed pyroclastic density current, controlled by gravity and terrain morphology. Such an interpretation is quantitatively supported by large-scale observations at Mount St. Helens and will infl uence the defi nition and predictive mapping of hazards on blast-dangerous volcanoes worldwide. ?? 2011 Geological Society of America.

  15. Deep long-period earthquakes under Mount St. Helens captured with dense recordings by iMUSH

    NASA Astrophysics Data System (ADS)

    Vidale, J. E.; Moran, S. C.; Creager, K. C.; Levander, A.; Malone, S. D.; Sisson, T. W.; Hotovec-Ellis, A. J.; Schmandt, B.

    2014-12-01

    Mysteries abound regarding the mechanism generating deep-long-period earthquakes (DLPs). DLPs are most commonly associated with the process of magma ascent from a deep source to a crustal reservoir, and plausible ideas include dehydration embrittlement, sluggish faulting, gurgling flow of magmatic fluids, and cooling of relic magma conduits. By good fortune, at least four DLPs occurred since the imaging Magma Under St Helens (iMUSH) experiment began in late June 2014. The DLPs were captured by 70 broadband seismometers in the passive array, and several were also recorded by the 3500 short-period seismometers deployed for the active experiment. These lower crust/upper mantle events were 20-35 km deep, offset less than 15 km from the crater, and have the low-frequency, long-duration reverberative waveforms, and lower crust/upper mantle locations characteristic of DLPs. One DLP had numerous bursts across ~100s, and two others consisted of two bursts within a minute. These are similar to the 19 DLPs seen beneath Mount St. Helens (MSH) previously [Nichols et al., 2011, JVGR]. We will also use these DLPs as templates in the search for others that are too small to be found otherwise. DLPs at MSH occur beneath the St. Helens Seismic Zone, proposed to be the block boundary between the Southern Washington Cascades Conductor and Siletzia rocks to the west. This actively-slipping and weak structural boundary could enhance the ability of magmatic fluids to reach the surface, and the co-located DLPs provide evidence for such fluid migration. We plan to investigate the frequency content, time evolution, spatial location, and clustering of DLPs under Mount St. Helens to shed light on the underlying physics and implications for shallower activity.

  16. Total sulfur dioxide emissions and pre-eruption vapor-saturated magma at Mount St. Helens, 1980-88

    SciTech Connect

    Gerlach, T.M.; McGee, K.A.

    1994-12-15

    SO{sub 2} from explosive volcanism can cause significant climatic and atmospheric impacts, but the source of the sulfur is controversial. TOMS, COSPEC, and ash leachate data for Mount St. Helens from the time of the climactic eruption on 18 May 1980 to the final stages of non-explosive degassing in 1988 give a total SO{sub 2} emission of 2 Mt. COSPEC data show a sharp drop in emission rate that was apparently controlled by a decreasing rate of magma supply. A total SO{sub 2} emission of only 0.08 Mt is estimated from melt inclusion data and the conventional assumption that the main sulfur source was pre-eruption melt; commonly invoked sources of {open_quotes}excess sulfur{close_quotes} (anhydrite decomposition, basaltic magma, and degassing of non-erupted magma) are unlikely in this case. Thus melt inclusions may significantly underestimate SO{sub 2} emissions and impacts of explosive volcanism on climate and the atmosphere. Measured CO{sub 2} emissions, together with the H{sub 2}O content of melt inclusions and experimental solubility data, indicate the Mount St. Helens dacite was vapor-saturated at depth prior to ascent and suggest that a vapor phase was the main source of sulfur for the 2-Mt of SO{sub 2}. A vapor source is consistent with experimental studies on the Mount St. Helens dacite and removes the need for a much debated shallow magma body. 23 refs., 3 figs.

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

    SciTech Connect

    Smith, D.R.

    1984-01-01

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

  18. Environmental Impact of the Helen, Research, and Chicago Mercury Mines on Water, Sediment, and Biota in the Upper Dry Creek Watershed, Lake County, California

    USGS Publications Warehouse

    Rytuba, James J.; Hothem, Roger L.; May, Jason T.; Kim, Christopher S.; Lawler, David; Goldstein, Daniel; Brussee, Brianne E.

    2009-01-01

    The Helen, Research, and Chicago mercury (Hg) deposits are among the youngest Hg deposits in the Coast Range Hg mineral belt and are located in the southwestern part of the Clear Lake volcanic field in Lake County, California. The mine workings and tailings are located in the headwaters of Dry Creek. The Helen Hg mine is the largest mine in the watershed having produced about 7,600 flasks of Hg. The Chicago and Research Hg mines produced only a small amount of Hg, less than 30 flasks. Waste rock and tailings have eroded from the mines, and mine drainage from the Helen and Research mines contributes Hg-enriched mine wastes to the headwaters of Dry Creek and contaminate the creek further downstream. The mines are located on federal land managed by the U.S. Bureau of Land Management (USBLM). The USBLM requested that the U.S. Geological Survey (USGS) measure and characterize Hg and geochemical constituents in tailings, sediment, water, and biota at the Helen, Research, and Chicago mines and in Dry Creek. This report is made in response to the USBLM request to conduct a Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA - Removal Site Investigation (RSI). The RSI applies to removal of Hg-contaminated mine waste from the Helen, Research, and Chicago mines as a means of reducing Hg transport to Dry Creek. This report summarizes data obtained from field sampling of mine tailings, waste rock, sediment, and water at the Helen, Research, and Chicago mines on April 19, 2001, during a storm event. Further sampling of water, sediment, and biota at the Helen mine area and the upper part of Dry Creek was completed on July 15, 2003, during low-flow conditions. Our results permit a preliminary assessment of the mining sources of Hg and associated chemical constituents that could elevate levels of monomethyl Hg (MMeHg) in the water, sediment, and biota that are impacted by historic mining.

  19. Geologic Map of the Saint Helens Quadrangle, Columbia County, Oregon, and Clark and Cowlitz Counties, Washington

    USGS Publications Warehouse

    Evarts, Russell C.

    2004-01-01

    The Saint Helens 7.5' quadrangle is situated in the Puget-Willamette Lowland approximately 35 km north Portland, Oregon. The lowland, which extends from Puget Sound into west-central Oregon, is a complex structural and topographic trough that lies between the Coast Range and the Cascade Range. Since late Eocene time, Cascade Range has been the locus of a discontinuously active volcanic arc associated with underthrusting of oceanic lithosphere beneath the North American continent along the Cascadia Subduction Zone. The Coast Range occupies the forearc position within the Cascadia arc-trench system and consists of a complex assemblage of Eocene to Miocene volcanic and marine sedimentary rocks. The Saint Helens quadrangle lies in the northern part of the Portland Basin, a roughly 2000-km2 topographic and structural depression. It is the northernmost of several sediment-filled structural basins that collectively constitute the Willamette Valley segment of the Puget-Willamette Lowland (Beeson and others, 1989; Swanson and others, 1993; Yeats and others, 1996). The rhomboidal basin is approximately 70 km long and 30 km wide, with its long dimension oriented northwest. The Columbia River flows west and north through the Portland Basin at an elevation near sea level and exits through a confined bedrock valley less than 2.5 km wide about 16 km north of Saint Helens. The flanks of the basin consist of Eocene through Miocene volcanic and sedimentary rocks that rise to elevations exceeding 2000 ft (610 m). Seismic-reflection profiles (L.M. Liberty, written commun., 2003) and lithologic logs of water wells (Swanson and others, 1993; Mabey and Madin, 1995) indicate that as much as 550 m of late Miocene and younger sediments have accumulated in the deepest part of the basin near Vancouver. Most of this basin-fill material was carried in from the east by the Columbia River but contributions from streams draining the adjacent highlands are locally important. The Portland Basin has

  20. Mount Saint Helens, Washington, USA, SRTM Perspective: Shaded Relief and Colored Height

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Mount Saint Helens is a prime example of how Earth's topographic form can greatly change even within our lifetimes. The mountain is one of several prominent volcanoes of the Cascade Range that stretches from British Columbia, Canada, southward through Washington, Oregon, and into northern California. Mount Adams (left background) and Mount Hood (right background) are also seen in this view, which was created entirely from elevation data produced by the Shuttle Radar Topography Mission.

    Prior to 1980, Mount Saint Helens had a shape roughly similar to other Cascade peaks, a tall, bold, irregular conic form that rose to 2950 meters (9677 feet). However, the explosive eruption of May 18, 1980, caused the upper 400 meters (1300 feet) of the mountain to collapse, slide, and spread northward, covering much of the adjacent terrain (lower left), leaving a crater atop the greatly shortened mountain. Subsequent eruptions built a volcanic dome within the crater, and the high rainfall of this area lead to substantial erosion of the poorly consolidated landslide material.

    Eruptions at Mount Saint Helens subsided in 1986, but renewed volcanic activity here and at other Cascade volcanoes is inevitable. Predicting such eruptions still presents challenges, but migration of magma within these volcanoes often produces distinctive seismic activity and minor but measurable topographic changes that can give warning of a potential eruption.

    Three visualization methods were combined to produce this image: shading of topographic slopes, color coding of topographic height, and then projection into a perspective view. The shade image was derived by computing topographic slope in the northeast-southwest (left to right) direction, so that northeast slopes appear bright and southwest slopes appear dark. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow and tan, to white at the highest elevations. The perspective

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

    USGS Publications Warehouse

    Glicken, Harry

    1996-01-01

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

  2. Effects of lava-dome emplacement on the Mount St. Helens crater glacier

    NASA Astrophysics Data System (ADS)

    Walder, J. S.; Schilling, S. P.; Denlinger, R. P.; Vallance, J. W.

    2004-12-01

    Since the end of the 1981-1986 episode of lava-dome growth at Mount St. Helens, an unusual glacier has grown rapidly within the crater of the volcano. The glacier, which is fed primarily by avalanching from the crater walls, contains about 30% rock debris by volume, has a maximum thickness of about 220 m and a volume of about 120 million cubic m, and forms a crescent that wraps around the old lava dome on both east and west sides. The new (October 2004) lava dome in the south of the crater began to grow centered roughly on the contact between the old lava dome and the glacier, in the process uplifting both ice and old dome rock. As the new dome is spreading to the south, the adjacent glacier is bulging upward. Firn layers on the outer flank of the glacier bulge have been warped upward almost vertically. In contrast, ice adjacent to the new dome has been thoroughly fractured. The overall style of deformation is reminiscent of that associated with salt-dome intrusion. Drawing an analogy to sand-box experiments, we suggest that the glacier is being deformed by high-angle reverse faults propagating upward from depth. Comparison of Lidar images of the glacier from September 2003 and October 2004 reveals not only the volcanogenic bulge but also elevated domains associated with the passage of kinematic waves, which are caused by glacier-mass-balance perturbations and have nothing to do with volcanic activity. As of 25 October 2004, growth of the new lava dome has had negligible hydrological consequences. Ice-surface cauldrons are common consequences of intense melting caused by either subglacial eruptions (as in Iceland) or subglacial venting of hot gases (as presently taking place at Mount Spurr, Alaska). However, there has been a notable absence of ice-surface cauldrons in the Mount St. Helens crater glacier, aside from a short-lived pond formed where the 1 October eruption pierced the glacier. We suggest that heat transfer to the glacier base is inefficient because

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

    NASA Astrophysics Data System (ADS)

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

    1983-06-01

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

  4. Completion of the 16 station Plate Boundary Observatory (PBO) network on Mt. St. Helens, WA

    NASA Astrophysics Data System (ADS)

    Austin, K.; Hafner, K.; Fengler, K.; Doelger, S.

    2006-12-01

    The Plate Boundary Observatory (PBO), part of the larger NSF-funded EarthScope project, is completing year 3 of the installation phase of 852 continuously operating GPS stations in the Western United States. Some of these GPS stations are focused specifically on centers of volcanic activity. Mt. St. Helens is one of these volcanic areas of interest in the Pacific Northwest (PNW) region. The PNW region will complete the installation of a 16 station GPS network on Mt. St. Helens during September 2006. This work also includes the co-location and installation of tiltmeters at four of the existing GPS sites. Network upgrades will be completed to handle the increase in data flow from the new GPS stations as well as the data from the tiltmeters and strainmeters. New GPS site installations include six helicopter accessible sites, and three drive to sites on the south flank of the mountain. Higher elevation sites will be outfitted with an eight battery, three solar panel power array to keep the stations operational during winter months. The remaining sites use a four battery, three solar panel array that has proved sufficient at other GPS locations over the past 2 winters. All stations will communicate via one of 2 radio networks set up on the mountain. The northern radio network transmits data for ten stations through a microwave connection at the Johnston Ridge observatory that also provides communications for PBO strainmeter, tiltmeter and CVO equipment. The remaining 10 stations on the south side of the mountain, are relayed through a hub at Washington State University's Vancouver Campus that is also providing data services for CVO. Results from analysis of data from both PBO and USGS GPS stations on the mountain, show a radially inward and downward motion, with the maximum vertical offsets high on the mountain and the maximum horizontal offsets located at distances of 5-10km from the crater. Displacements are small over the 2004-present eruption with a maximum of 3cm

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

    USGS Publications Warehouse

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

    1982-01-01

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

  6. Investigating microseismicity and crustal structure beneath Mount St. Helens with a 900-geophone array

    NASA Astrophysics Data System (ADS)

    Schmandt, B.; Hansen, S. M.; Kiser, E.; Levander, A.; Wang, Y.; Lin, F. C.

    2015-12-01

    During Summer 2014 we deployed ~900 cable-free seismographs within ~12 km of Mount St. Helens. Each seismograph contained a 10-Hz geophone and recorded continuously for two weeks with a sample rate of 250 Hz. The array temporarily provides a major increase in spatial coverage compared to the 10-station long-term monitoring array, but each of the geophone has a high noise floor compared to the force-feedback sensors of the long-term array that is part of the Pacific Northwest Seismic Network (PNSN). We are investigating the utility of the geophone array for source and structural analyses using ambient noise, high-frequency microseismicity, deep long-period seismicity, and 23 controlled sources from the concurrent iMUSH active source project. Surface waves extracted from ambient noise cross-correlation have adequate signal to noise ratios for upper crustal tomography using frequencies ~0.2-0.5 Hz. Efforts to extract higher frequency body waves with interferometry are ongoing and include focusing on time periods with stronger high frequency noise or coda from controlled sources and earthquakes. Continuous back-projection of the array data into the 3-D subsurface was used to automatically detect and locate high-frequency (>5 Hz) microseismicity extending down to ~M-2, with a completeness magnitude of ~0.3. Two deep crustal low frequency earthquakes (<5 Hz) detected by PNSN occurred during our survey. We relocated these events and are using them to optimize back-projection parameters and create matched filters to search for additional deep low frequency seismicity. One of the deep low frequency events locates at approximately Moho depth using back-projection of S-wave energy and S-P times from dense geophone sub-arrays. This event occurs just southeast of Mount St. Helens in an area where controlled source refraction tomography images anomalously slow lower crust and common midpoint stacking images a bright Moho indicative of a locally high impedance contrast between

  7. Subsurface Imaging at Mount St. Helens with a Large-N Geophone Array

    NASA Astrophysics Data System (ADS)

    Hansen, S. M.; Schmandt, B.; Levander, A.; Kiser, E.; Vidale, J. E.; Moran, S. C.

    2015-12-01

    The 900-instrument Mount St. Helens nodal array recorded continuous data for approximately two weeks in the summer of 2014 and provides a remarkable opportunity to interrogate the structure beneath an active arc volcano. Two separate imaging techniques are applied to constrain both the distribution of microseismicity and subsurface velocity structure. Reverse-time source imaging is applied to the 10 km3 region beneath the volcanic edifice where most of cataloged seismicity occurred during the experiment. These efforts resulted in an order of magnitude increase in earthquake detections over the normal monitoring operations of the Pacific Northwest Seismic Network. Earthquake locations resolve a narrow, ≤1 km wide, vertical lineament of seismicity that extends from the surface to 4 km depth directly beneath the summit crater, consistent with the historical event distribution of Waite and Moran[2009]. This feature is interpreted as a fracture network that acts as a conduit connecting an underlying magma chamber to the surface. Moho imaging is achieved using the near-offset (< 30 km) PmP phase generated by the iMUSH active source shots that occurred during the deployment. The PmP arrivals are enhanced using short-term-average over long-term-average processing and then migrated using a 3D velocity model. The observed Moho depths range from 35-40 km with a slight eastward deepening across the Mt St Helens fracture zone. Significant variations are observed in the Moho reflectivity. Large amplitude PmP energy is observed in shots originating from the north and east whereas shots from the south-west display little-to-no PmP energy. The region above the reflective Moho is approximately coincident with areas displaying reduced lower-crustal velocities in the initial iMUSH tomography models and may therefore contain fluids and/or partial melt. Additional evidence for lower crustal fluids in this region is provided by deep-long-period (DLP) events which have historically been

  8. Magma reservoirs from the upper crust to the Moho inferred from high-resolution Vp and Vs models beneath Mount St. Helens, Cascades, USA

    NASA Astrophysics Data System (ADS)

    Kiser, Eric; Levander, Alan; Zelt, Colin; Palomeras, Imma; Schmandt, Brandon; Hansen, Steven; Creager, Kenneth; Ulberg, Carl

    2016-04-01

    Mount St. Helens is currently the most active volcano along the Cascadia arc. Though several studies investigated the magmatic system beneath Mount St. Helens following the May 18, 1980 eruption, tomographic imaging of the system has been limited to ~10 km depth due to the distribution of earthquakes in the region. This has made it difficult to estimate the volume of the shallow magma reservoir beneath the volcano, the regions of magma entry into the lower crust, and the connectivity of this magma system throughout the crust. The latter is particularly interesting as one interpretation of the Southern Washington Cascades Conductor (SWCC) suggests that the Mount St Helens and Mount Adams volcanic systems are connected in the middle crust (Hill et al., 2009). The multi-disciplinary iMUSH (imaging Magma Under St. Helens) project is designed to investigate these and other fundamental questions associated with Mount St. Helens. Here we present the first high-resolution 2D Vp and Vs models derived from travel-time data from the iMUSH 3D active-source seismic experiment. The experiment consisted of ~6000 seismograph stations which recorded 23 explosions and hundreds of local earthquakes. Directly beneath Mount St. Helens, we observe a high Vp/Vs body, inferred to be the upper/middle crustal magma reservoir, between 4 and 13 km depth. We observe a second high Vp/Vs body, likely of magmatic origin, at roughly the same depth beneath Indian Heaven Volcanic Field, which last erupted 9 ka. Southeast of Mount St. Helens is a low Vp column extending from the middle crust, ~15 km depth, to the Moho at ~40 km depth. A cluster of deep long-period events, typically associated with injection of magma, occurs at the northwestern boundary of this low Vp column. We interpret this as the middle-lower crust magma reservoir. In the lower crust, high Vp features bound the magma reservoir directly beneath Mount St. Helens and the Indian Heaven Volcanic Field. One explanation for these high Vp

  9. Bimodal Density Distribution of Cryptodome Dacite from the 1980 Eruption of Mount St. Helens, Washington

    USGS Publications Warehouse

    Hoblitt, R.P.; Harmon, R.S.

    1993-01-01

    The explosion of a cryptodome at Mount St. Helens in 1980 produced two juvenile rock types that are derived from the same source magma. Their differences-color, texture and density-are due only to vesicularity differences. The vesicular gray dacite comprises bout 72% of the juvenile material; the black dacite comprises the other 28%. The density of juvenile dacite is bimodally distributed, with peaks at 1.6 g cm-3 (gray dacite) and 2.3 g cm-3 (black dacite). Water contents, deuterium abundances, and the relationship of petrographic structures to vapor-phase crystals indicate both rock types underwent pre-explosion subsurface vesiculation and degassing. The gray dacite underwent a second vesiculation event, probably during the 18 May explosion. In the subsurface, gases probably escaped through interconnected vesicles into the permeable volcanic edifice. We suggest that nonuniform degassing of an initially homogeneous magma produced volatile gradients in the cryptodome and that these gradients were responsible for the density bimodality. That is, water contents less than about 0.2-0.4 wt% produced vesicle growth rates that were slow in comparison to the pyroclast cooling rates; greater water contents produced vesicle growth rates that were fast in comparison to cooling rates. In this scheme, the dacite densities are bimodally distributed simply because, following decompression on 18 May 1980, one clast population vesiculated while the other did not. For clasts that did vesiculate, vesicle growth continued until it was arrested by fragmentation. ?? 1993 Springer-Verlag.

  10. Yellow Cat revisited: a review of Helen Cannon's selenium indicator plants

    SciTech Connect

    Arp, G.K.

    1983-03-01

    In the late 1940s, Helen Cannon of the USGS conducted her famous studies on the association of plants to selenium. She used this association for detection of sedimentary uranium deposits on the Colorado plateau. Cannon demonstrated that locoweeds (Astragalus) from the Yellow Cat area of the Thompson district in eastern Utah did reflect the presence of selenium-rich uranium deposits by their colonization of the soils over the deposits. During the subsequent 30 years, Cannon's work has repeatedly been cited as a classic example of the use of indicator geobotany in mineral exploration. During the same 30-year period, geobotanical techniques have not found wide utilization as an exploration tool. Further, Cannon's work has not been demonstrated elsewhere to any extent. In 1980, the author returned to Yellow Cat to see what changes, if any, may have transpired at the site. The author also wanted to gather insight into why geobotanical methods have not gained wider acceptance and perhaps determine why subsequent work is so rare. Results of this study support Cannon's basic work. The results also suggest that the methods are ecologically sound and have applicability to modern mineral exploration programs. Limitations to the method are also discussed, along with some speculation as to why geobotanical methods have not seen wider application.

  11. Secondary hydroeruptions in pyroclastic-flow deposits: Examples from Mount St. Helens

    USGS Publications Warehouse

    Moyer, T.C.; Swanson, D.A.

    1987-01-01

    Secondary hydroeruptions occur in pyroclastic-flow deposits when water or ice is trapped beneath hot pyroclastic debris and rapidly heated to steam. These eruptions display various styles of activity including fumarolic degassing, tephra fountaining, and explosive cratering. The deposits, which occupy the layer 3 stratigraphic position on the top of pyroclastic-flow units, can be distinguished from ash-cloud material by lateral thickness variation, clast composition, and other sedimentary features. The ejecta of secondary hydroeruptions comprise a subset of hydrovolcanic pyroclastic deposits. A small secondary hydroeruption observed on the Mount St. Helens pumice plain in 1981 produced tephra that was emplaced ballistically, by deposition from base surges, and by fallout from an eruption column. Stratigraphic descriptions and grain-size analysis of the ejecta from several secondary craters on the pumice plain demonstrate that the bedforms produced by a hydroeruption change with crater diameter. In particular, craters of small diameter are surrounded by interbedded ripple-laminated ash horizons and nonstratified, fines-depleted units; large craters have ejecta ramparts comprised of coarse dunes and antidunes. These bedform changes are related to a progressive increase in eruptive energy, which produces base surges of greater power and eruptive columns of greater height. We suggest that the style of activity displayed during a secondary hydroeruption is controlled by both the total thermal energy of the system and the permeability of the pyroclastic overburden. ?? 1987.

  12. Erosional furrows formed during the lateral blast at Mount St. Helens, May 18, 1980

    USGS Publications Warehouse

    Kieffer, S.W.; Sturtevant, B.

    1988-01-01

    Nearly horizontal, quasi-periodic erosional features of 7-m average transverse wavelength and of order 100-m length occur in scattered locations from 3.5 to 9 km from the crater at Mount St. Helens under deposits of the lateral blast of May 18, 1980. We attribute the erosional features to scouring by longitudinal vortices resulting from flow instabilities induced by complex topography, namely, by streamline curvature in regions of reattachment downstream of sheltered regions, and by the cross-flow component of flow subparallel to ridge crests. The diameter of the vortices and their transverse spacing, inferred from the distance between furrows, are taken to be of the order of the boundary layer thickness. The inferred boundary layer thickness (???14 m at 9 km from the source of the blast) is consistent with the running length from the mountain to the furrow locations. The orientation of furrows induced by the cross-flow instability can be used to measure the upwash angle and estimate the flow Mach number: at the central ridge of Spirit Lake the Mach number is inferred to have been about 2.5, and the flow velocity approximately 235 m/s. -from Authors

  13. Digital database of channel cross-section surveys, Mount St. Helens, Washington

    USGS Publications Warehouse

    Mosbrucker, Adam R.; Spicer, Kurt R.; Major, Jon J.; Saunders, Dennis R.; Christianson, Tami S.; Kingsbury, Cole G.

    2015-08-06

    Stream-channel cross-section survey data are a fundamental component to studies of fluvial geomorphology. Such data provide important parameters required by many open-channel flow models, sediment-transport equations, sediment-budget computations, and flood-hazard assessments. At Mount St. Helens, Washington, the long-term response of channels to the May 18, 1980, eruption, which dramatically altered the hydrogeomorphic regime of several drainages, is documented by an exceptional time series of repeat stream-channel cross-section surveys. More than 300 cross sections, most established shortly following the eruption, represent more than 100 kilometers of surveyed topography. Although selected cross sections have been published previously in print form, we present a comprehensive digital database that includes geospatial and tabular data. Furthermore, survey data are referenced to a common geographic projection and to common datums. Database design, maintenance, and data dissemination are accomplished through a geographic information system (GIS) platform, which integrates survey data acquired with theodolite, total station, and global navigation satellite system (GNSS) instrumentation. Users can interactively perform advanced queries and geospatial time-series analysis. An accuracy assessment provides users the ability to quantify uncertainty within these data. At the time of publication, this project is ongoing. Regular database updates are expected; users are advised to confirm they are using the latest version.

  14. Erosion by flowing lava: Geochemical evidence in the Cave Basalt, Mount St. Helens, Washington

    USGS Publications Warehouse

    Williams, D.A.; Kadel, S.D.; Greeley, R.; Lesher, C.M.; Clynne, M.A.

    2004-01-01

    We sampled basaltic lava flows and underlying dacitic tuff deposits in or near lava tubes of the Cave Basalt, Mount St. Helens, Washington to determine whether the Cave Basalt lavas contain geochemical evidence of substrate contamination by lava erosion. The samples were analyzed using a combination of wavelength-dispersive X-ray fluorescence spectrometry and inductively-coupled plasma mass spectrometry. The results indicate that the oldest, outer lava tube linings in direct contact with the dacitic substrate are contaminated, whereas the younger, inner lava tube linings are uncontaminated and apparently either more evolved or enriched in residual liquid. The most heavily contaminated lavas occur closer to the vent and in steeper parts of the tube system, and the amount of contamination decreases with increasing distance downstream. These results suggest that erosion by lava and contamination were limited to only the initially emplaced flows and that erosion was localized and enhanced by vigorous laminar flow over steeper slopes. After cooling, the initial Cave Basalt lava flows formed an insulating lining within the tubes that prevented further erosion by later flows. This interpretation is consistent with models of lava erosion that predict higher erosion rates closer to sources and over steeper slopes. A greater abundance of xenoliths and xenocrysts relative to xenomelts in hand samples indicates that mechanical erosion rather than thermal erosion was the dominant erosional process in the Cave Basalt, but further sampling and petrographic analyses must be performed to verify this hypothesis. ?? Springer-Verlag 2003.

  15. Time variations of aerosols in the stratosphere following Mount St. Helens eruptions

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    Samples of stratospheric aerosols collected with U-2 aircraft for several months following the first three major eruptions of Mount St. Helens were analyzed for ash and liquid acid content. Ash grain sizes and compositions vary depending on collection altitude, location within the drifting cloud, and days following their injection. s computers Size distributions of ash particles vary with altitude. Generally small particles are depleted more rapidly at low altitudes (12 km) than at higher altitudes (17-18 km). Although samples collected 1 day after the first eruption of May 18, 1980, were dry, flow marks on the aircraft indicated parts of the cloud contained heavy acid concentrations. Indeed, all other samples obtained within 1 to 4 days after later eruptions (May 25 and June 12, 1980) were covered with copious amounts of liquid acid. Proportions of liquid to ash varied considerably depending on sampling location and cloud age. Because the acid-coated ash globules were large, they rapidly fell from the stratosphere until, by late June 1980, only a residue of acid droplets remained. Size distributions and concentrations of these droplets varied considerably.

  16. Temporal changes in stress preceding the 2004-2008 eruption of Mount St. Helens, Washington

    USGS Publications Warehouse

    Lehto, H.L.; Roman, D.C.; Moran, S.C.

    2010-01-01

    The 2004-2008 eruption of Mount St. Helens (MSH), Washington, was preceded by a swarm of shallow volcano-tectonic earthquakes (VTs) that began on September 23, 2004. We calculated locations and fault-plane solutions (FPS) for shallow VTs recorded during a background period (January 1999 to July 2004) and during the early vent-clearing phase (September 23 to 29, 2004) of the 2004-2008 eruption. FPS show normal and strike-slip faulting during the background period and on September 23; strike-slip and reverse faulting on September 24; and a mixture of strike-slip, reverse, and normal faulting on September 25-29. The orientation of ??1 beneath MSH, as estimated from stress tensor inversions, was found to be sub-horizontal for all periods and oriented NE-SW during the background period, NW-SE on September 24, and NE-SW on September 25-29. We suggest that the ephemeral ~90?? change in ??1 orientation was due to intrusion and inflation of a NE-SW-oriented dike in the shallow crust prior to the eruption onset. ?? 2010 Elsevier B.V.

  17. Geologic map of the Sasquatch Steps area, north flank of Mount St. Helens, Washington

    USGS Publications Warehouse

    Hausback, Brian P.

    2000-01-01

    The 1980 eruption of Mount St. Helens resulted in both new volcanic deposits and deeply incised exposures into pre-1980 deposits. These exposures were produced by excavation of the crater by the 1980 landslides and lateral explosion as well as the subsequent erosion of Step and Loowit creeks by northerly stream flow out of the horseshoe-shaped crater. The map covers the area known as the Sasquatch Steps (commonly called the Steps), which lies between the Pumice Plain on the north and the lowermost portion of the crater on the south. Rapid alluvial aggradation at the base of the Steps is presently burying some of the lowest exposures, and erosion is stripping many of the upland deposits. The stratigraphic sequence exposed in the map area includes deposits from the eruptive periods listed in table 1 (Crandell, 1987). Assignment of deposits to the various eruptive periods is based on lithology and ferromagnesian-mineral suites typical for each of the eruptive periods (Mullineaux and Crandell, 1981; Mullineaux, 1986), as well as three 14 C dates from wood found in the deposits. Faults displayed on the map are largely confined to the older part of the stratigraphic section. These older units are highly shattered, with an extremely complicated fracture pattern, and it is only possible to show the largest and most distinctive of these structures at the map scale. Interpretation of the stratigraphy and structure of this area is given in Hausback and Swanson (1990).

  18. Precursor gases of aerosols in the Mount St. Helens eruption plumes at stratospheric altitudes

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    Nineteen stratospheric samples from the eruption plumes of Mount St. Helens were collected in five flight experiments. The plume samples were collected at various altitudes from 13.1 to 20.7 km by using the Ames cryogenic sampling system on board the NASA U-2 aircraft. The enriched, cryogenically collected samples were analyzed by chromatography. The concentrations of aerosols precursor gases (OCS, SO2, and CS2), CH3Cl, N2O, CF2Cl2, and CFCl3 were measured by gas chromatography. Large enhancement of the mixing ratio of SO2 and moderate enhancement of CS2 and OCS were found in the plume samples compared with similar measurement under pre-volcanic conditions. A fast decay rate of the SO2 mixing ratio in the plume was observed. Measurement of Cl(-), SO2(2-), and NO3(-) by ion chromatography was also carried out on water solutions prepared from the plume samples. The results obtained with this technique imply large mixing ratios of HCl, (NO + NO2 + HNO3), and SO2, in which these constituents are the respective sources of the anions. Measurement of the Rn222 concentration in the plume was made. Other stratospheric constituents in the plume samples, such as H2O, CO2, CH4, and CO, were also observed.

  19. Geospatial and statistical analysis of volcanic ash leachate data from Mt. St. Helens

    NASA Astrophysics Data System (ADS)

    Ayris, P. M.; Delmelle, P.; Pereira, B.; Damby, D. E.; Durant, A. J.; Maters, E. C.; Dingwell, D. B.

    2014-12-01

    Upon contact with water, freshly-fallen volcanic ash releases a pulse of readily soluble material, derived from dissolution of S-, Cl- and F-bearing salts formed on ash surfaces during transport through the volcanic eruption plume. Analysis of leachate solutions can provide insight into the spatial and temporal variations in surface salt loadings, and hence the processes by which they were emplaced, and the hazards which they may induce upon mobilisation within receiving environments. However, excluding a small number of publications from the 1970's and 1980's, leachate studies are often limited by the use of small datasets with an uncertain capacity to adequately represent their parent ash deposit. Here we illustrate the significance of such limitations through the compilation and interrogation of a database of 96 published leachate compositions from 6 studies which investigated the May 18th, 1980 eruption of Mt. St. Helens. Utilising statistical analysis techniques, we removed outliers and biases between studies by linear transformation in order to produce a useable ash leachate dataset. The corrected data were mapped by kriging method to derive the spatial distribution of soluble S and Cl concentrations downwind of the volcano. Our treatment highlighted spatial trends in leachate data which may reflect various volcanic and atmospheric processes. In order to be able to disentangle these processes, we emphasise the need to obtain a homogeneous spatial distribution when sampling ash for leaching purposes, and to conduct those analyses according to a standardized protocol.

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

    USGS Publications Warehouse

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

    2005-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

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

  2. Analysis of seismic body waves excited by the Mount St. Helens eruption of May 18, 1980

    NASA Technical Reports Server (NTRS)

    Kanamori, H.; Given, J. W.; Lay, T.

    1984-01-01

    Seismic body waves which were excited by eruption of Mt. St. Helens, and recorded by the Global Digital Seismographic Network (GDSN) stations are analyzed to determine the nature and the time sequence of the events associated with the eruption. The polarity of teleseismic P waves (period 20 sec) is identical at six stations which are distributed over a wide azimuthal range. This observation, together with a very small S to P amplitude ratio (at 20 sec), suggests that the source is a nearly vertical single force that represents the counter force of the eruption. The time history of the vertical force suggests two distinct groups of events, about two minutes apart, each consisting of several subevents with a duration of about 25 sec. The magnitude of the force is approximately 2.6 to the 17th power dyne. This vertical force is in contrast with the long period (approximately 150 sec) southward horizontal single force which was determined by a previous study and interpreted to be due to the massive landslide. Previously announced in STAR as N83-15968

  3. Analysis of seismic body waves excited by the Mount Saint Helens eruption of May 18, 1980

    NASA Technical Reports Server (NTRS)

    Kanamori, H.; Given, J. W.; Lay, T.

    1982-01-01

    Seismic body waves which were excited by eruption of Mt. St. Helens, and recorded by the Global Digital Seismographic Network (GDSN) stations are analyzed to determine the nature and the time sequence of the events associated with the eruption. The polarity of teleseismic P waves (period 20 sec) is identical at six stations which are distributed over a wide azimuthal range. This observation, together with a very small S to P amplitude ratio (at 20 sec), suggests that the source is a nearly vertical single force that represents the counter force of the eruption. The time history of the vertical force suggests two distinct groups of events, about two minutes apart, each consisting of several subevents with a duration of about 25 sec. The magnitude of the force is approximately 2.6 to the 17th power dyne. this vertical force is in contrast with the long period (approximately 150 sec) southward horizontal single force which was determined by a previous study and interpreted to be due to the massive landslide.

  4. Ash loading and insolation at Hanford, Washington during and after the eruption of Mount St. Helens

    NASA Technical Reports Server (NTRS)

    Laulainen, N. S.

    1982-01-01

    The effects of volcanic ash suspended in the atmosphere on the incident solar radiation was monitored at the Hanford Meteorological Station (HMS) subsequent to the major eruption of Mount St. Helens on May 18, 1980. Passage of the ash plume over Hanford resulted in a very dramatic decrease of solar radiation intensity to zero. A reduction in visibility to less than 1 km was observed, as great quantities of ash fell out of the plume onto the ground. Ash loading in the atmosphere remained very high for several days following the eruption, primarily as a result of resuspension from the surface. Visibilities remained low (2 to 8 km) during this period. Estimates of atmospheric turbidity were made from the ratio of diffuse-to-direct solar radiation; these turbidities were used to estimate extinction along a horizontal path, a quantity which can be related to visibility. Comparisons of observed and estimated visibilities were very good, in spite of the rather coarse approximations used in the estimates. Atmospheric clarity and visibility improved to near pre-eruption conditions following a period of rain showers. The diffuse-to-direct ratio of solar radiation provided a useful index for estimating volcanic ash loading of the atmosphere.

  5. Source Mechanism of Tiny Long-Period Events at Mount St. Helens in July 2005

    NASA Astrophysics Data System (ADS)

    Matoza, R. S.; Chouet, B. A.; Dawson, P. B.; Shearer, P. M.; Haney, M. M.; Waite, G. P.; Moran, S. C.; Mikesell, T. D.

    2015-12-01

    Long-period (LP, 0.5-5 Hz) seismicity is a recognized signature of unrest and eruption at volcanoes worldwide. The characteristic seismicity during the sustained dome-building phase of the 2004-2008 eruption of Mount St. Helens (MSH), USA was cyclic LP "drumbeating". However, accompanying the LP drumbeating was a near-continuous, randomly occurring series of tiny LP seismic events (LP "subevents"), which may hold important additional information on the mechanism of seismogenesis at restless volcanoes. We employ template matching, phase-weighted stacking, and full-waveform inversion to image the source mechanism of one multiplet of these LP subevents at MSH in July 2005. We apply network-based template matching to 8 days of continuous velocity waveform data from 29 June to 7 July 2005. We stack waveforms for high-quality triggers at each station and component, using a combination of linear and phase-weighted stacking to produce clean stacks for use in waveform inversion. The derived source mechanism points to the volumetric oscillation (~10 m3) of a subhorizontal crack located at shallow depth (~30 m) in an area to the south of Crater Glacier in the southern portion of the breached MSH crater. A possible excitation mechanism is the sudden condensation of metastable steam from a shallow pressurized hydrothermal system as it encounters cool meteoric water in the outer parts of the edifice.

  6. Four-year prospective study of the respiratory effects of volcanic ash from Mt. St. Helens

    SciTech Connect

    Buist, A.S.; Vollmer, W.M.; Johnson, L.R.; Bernstein, R.S.; McCamant, L.E.

    1986-04-01

    This report describes the 4-yr follow-up of 712 loggers exposed over an extended period to varying levels of fresh volcanic ash from the 1980 eruptions of Mt. St. Helens. Concerns related to the irritant effect the ash might have on the airways and also to its fibrogenic potential if exposures were intense and continued over many years. Our subjects were divided into 3 groups: high, low, and no exposure. Baseline testing was begun in June 1980, 1 month after the major eruption, and follow-up testing continued on an annual basis through 1984; 88% of the loggers have been tested at least 3 times. Analysis of lung function data showed that a significant, exposure-related decline in FEV1 occurred during the first year after the eruption. The decline was short-lived, however, and by 1984 the differences between exposure groups were no longer significant. Self-reported symptoms of cough, phlegm, and wheeze showed a similar pattern. No ash-related changes were seen in chest roentgenograms taken in 1980 and in 1984. Our findings are consistent with the hypothesis that the inhaled ash caused mucus hypersecretion and/or airway inflammation that reversed when the exposure levels decreased. The ash levels to which the loggers were exposed were low compared with permissible occupational levels for nuisance dusts, but generally higher than the total suspended particulate levels permissible in ambient air.

  7. Drainage evolution in the debris avalanche deposits near Mount Saint Helens, Washington

    NASA Technical Reports Server (NTRS)

    Beach, G. L.; Dzurisin, D.

    1984-01-01

    The 18 May 1980 eruption of Mount St. Helens was initiated by a massive rockslide-debris avalanche which completely transformed the upper 25 km of the North Fork Toutle River valley. The debris was generated by one of the largest gravitational mass movements ever recorded on Earth. Moving at an average velocity of 35 m/s, the debris avalanche buried approximately 60 sq km of terrain to an average depth of 45 m with unconsolidated, poorly sorted volcaniclastic material, all within a period of 10 minutes. Where exposed and unaltered by subsequent lahars and pyroclastic flows, the new terrain surface was characterized predominantly by hummocks, closed depressions, and the absence of an identifiable channel network. Following emplacement of the debris avalanche, a complex interrelationship of fluvial and mass wasting processes immediately began operating to return the impacted area to an equilibrium status through the removal of material (potential energy) and re-establishment of graded conditions. In an attempt to chronicle the morphologic evolution of this unique environmental setting, a systematic series of interpretative maps of several selected areas was produced. These maps, which document the rate and character of active geomorphic processes, are discussed.

  8. Ambient noise tomography across Mount St. Helens using a dense seismic array

    NASA Astrophysics Data System (ADS)

    Wang, Yadong; Lin, Fan-Chi; Schmandt, Brandon; Farrell, Jamie

    2017-06-01

    We investigated upper crustal structure with data from a dense seismic array deployed around Mount St. Helens for 2 weeks in the summer of 2014. Interstation cross correlations of ambient seismic noise data from the array were obtained, and clear fundamental mode Rayleigh waves were observed between 2.5 and 5 s periods. In addition, higher-mode signals were observed around 2 s period. Frequency-time analysis was applied to measure fundamental mode Rayleigh wave phase velocities, which were used to invert for 2-D phase velocity maps. An azimuth-dependent traveltime correction was implemented to mitigate potential biases introduced due to an inhomogeneous noise source distribution. Reliable phase velocity maps were only obtained between 3 and 4 s periods due to limitations imposed by the array aperture and higher-mode contamination. The phase velocity tomography results, which are sensitive to structure shallower than 6 km depth, reveal an 10-15% low-velocity anomaly centered beneath the volcanic edifice and peripheral high-velocity anomalies that likely correspond to cooled igneous intrusions. We suggest that the low-velocity anomaly reflects the high-porosity mixture of lava and ash deposits near the surface of the edifice, a highly fractured magmatic conduit and hydrothermal system beneath the volcano, and possibly a small contribution from silicate melt.

  9. Mt. St. Helens: Influence of Magmatic Activity on the Biogeochemistry of Thermal Springs

    NASA Astrophysics Data System (ADS)

    Montross, S. N.; Skidmore, M.; Abrahamson, I. S.

    2005-12-01

    Mt St. Helens erupted explosively in 1980, and the intense heat of this event effectively sterilized the crater. The crater is filled with significant ash and volcanic debris and the crater environment has limited vegetation despite relatively abundant water, from rainfall and snowmelt. However, microorganisms thrive in the hot springs that have developed in the crater since the 1980 eruption in this otherwise biologically hostile environment. Channelized drainages exiting the crater contain numerous hot spring sources which result from thermal heating of meteoric water and gain solutes from water-rock interactions. These solutes are important inputs for the microbial communities found within the crater thermal systems. Water samples collected in August 2004 and August 2005 from thermal springs in Step Canyon allow the opportunity to assess the effects of recent magmatic activity in the crater since September 2004, on the aqueous chemistry and microbiology of thermal spring water. We have investigated the composition of microbial communities in crater hot spring ecosystems by identifying small subunit ribosomal RNA sequences amplified directly from extracted genomic DNA. Initial screening of cloned DNA (16S rRNA gene sequence) by restriction fragment length polymorphism and sequencing indicates moderate microbial diversity in this environment with representatives from the domains Bacteria and Archaea. The presentation will examine relationships between the aqueous geochemistry and the microbial communities and temporal changes in these related to the recent magmatic activity.

  10. Why did Alfred Blalock and Helen Taussig not receive the nobel prize?

    PubMed

    Hansson, Nils; Schlich, Thomas

    2015-06-01

    From the 1940s to the 1960s, the number of cardiac surgeons nominated for the Nobel Prize for Physiology or Medicine grew rapidly. These nominations pinpoint major developments ranging from the first closed extracardiac operations to the era of complete intracardiac repair and treatment of congenital heart diseases. The aim of this article is to present the motivations for the numerous Nobel Prize nominations for the cardiac surgeon Alfred Blalock and the pediatric cardiologist Helen B. Taussig, and to show why the Nobel committee finally chose not to award them for the development of the Blalock-Taussig shunt. The authors have gathered and analyzed files on Blalock and Taussig from the Nobel Prize archive for Physiology and Medicine in Solna, Sweden. More than forty scholars, primarily from the United States and Europe, nominated Blalock and Taussig for the Nobel Prize for Physiology or Medicine. Such a strong transatlantic support is rare for nominated surgeons. The authors discuss why the number of Nobel Prize nominations for cardiac surgeons in general reached a climax around the 1950s and formulate open research questions on why relatively few surgeons have received the prestigious prize for the development of surgical procedures. © 2015 Wiley Periodicals, Inc.

  11. Mount St. Helens Ash from the 18 May 1980 Eruption: Chemical, Physical, Mineralogical, and Biological Properties

    NASA Astrophysics Data System (ADS)

    Fruchter, Jonathan S.; Robertson, David E.; Evans, John C.; Olsen, Khris B.; Lepel, Elwood A.; Laul, Jagdish C.; Abel, Keith H.; Sanders, Ronald W.; Jackson, Peter O.; Wogman, Ned S.; Perkins, Richard W.; van Tuyl, Harold H.; Beauchamp, Raymond H.; Shade, John W.; Leland Daniel, J.; Erikson, Robert L.; Sehmel, George A.; Lee, Richard N.; Robinson, Alfred V.; Moss, Owen R.; Briant, James K.; Cannon, William C.

    1980-09-01

    Samples of ash from the 18 May 1980 eruption of Mount St. Helens were collected from several locations in eastern Washington and Montana. The ash was subjected to a variety of analyses to determine its chemical, physical, mineralogical, and biological characteristics. Chemically, the ash samples were of dacitic composition. Particle size data showed bimodal distributions and differed considerably with location. However, all samples contained comparable amounts of particles less than 3.5 micrometers in diameter (respirable fraction). Mineralogically, the samples ranged from almost totally glassy to almost totally crystalline. Crystalline samples were dominated by plagioclase feldspar (andesine) and orthopyroxene (hypersthene), with smaller amounts of titanomagnetite and hornblende. All but one of the samples contained from less than 1 percent to 3 percent free crystalline silica (quartz, trydimite, or cristobalite) in both the bulk samples and 1 to 2 percent in the fractions smaller than 3.5 micrometers. The long-lived natural radionuclide content of the ash was comparable to that of crustal material; however, relatively large concentrations of short-lived radon daughters were present and polonium-210 content was inversely correlated with particle size. In vitro biological tests showed the ash to be nontoxic to alveolar macrophages, which are an important part of the lungs' natural clearance mechanism. On the basis of a substantial body of data that has shown a correlation between macrophage cytotoxicity and fibrogenicity of minerals, the ash is not predicted to be highly fibrogenic.

  12. GOES weather satellite observations and measurements of the May 18, 1980, Mount St. Helens eruption

    NASA Technical Reports Server (NTRS)

    Holasek, R. E.; Self, S.

    1995-01-01

    We demonstrate the use of Geostationary Operational Environmental Satellite (GOES) images of the May 18, 1980, Mount St. Helens volcanic plume in providing details of the dynamics and changing character of this major explosive eruption. Visible and thermal infrared (IR) data from a sequence of images at 30-min intervals from 0850 to 1720 Local Time (LT) give information on dispersal and plume top temperature. Initial visible and IR images at 0850 show the top of a spreading co-ignimbrite-like umbrella plume and an overshooting column emerging from it, both rising off the ground-hugging pyroclastic gravity flow generated by the opening directed blast. The overshooting column had a minimum temperature significantly colder than local ambient atmosphere, indicating substantial undercooling, and a maximum altitude of 31 +/- 2 km at 0920. This large plume system then formed a high-velocity, radially spreading, gravitationally driven current before becoming advected in the wind field at an average downwind velocity of 29 m/s. Reflectance values from visible GOES data change from lower to higher during periods of transition from darker toned Plinian to lighter toned co-ignimbrite plumes indicating that in this case satellite data resolved changes in eruptive style from plumes with a coarser to a finer dominant particle size.

  13. Sediment yield following severe volcanic disturbance - A two-decade perspective from Mount St. Helens

    USGS Publications Warehouse

    Major, J.J.; Pierson, T.C.; Dinehart, R.L.; Costa, J.E.

    2000-01-01

    Explosive volcanic eruptions perturb water and sediment fluxes in watersheds; consequently, posteruption sediment yields can exceed pre-eruption yields by several orders of magnitude. Annual suspended-sediment yields following the catastrophic 1980 Mount St. Helens eruption were as much as 500 times greater than typical background level, and they generally declined nonlinearly for more than a decade. Although sediment yields responded primarily to type and degree of disturbance, streamflow fluctuations significantly affected sediment-yield trends. Consecutive years (1995-1999) of above-average discharge reversed the nonlinear decline and rejuvenated yields to average values measured within a few years of the eruption. After 20 yr, the average annual suspended-sediment yield from the 1980 debris-avalanche deposit remains 100 times (104 Mg [megagrams]/km2) above typical background level (~102 Mg/km2). Within five years of the eruption, annual yields from valleys coated by lahar deposits roughly plateaued, and average yields remain about 10 times (103 Mg/km2) above background level. Yield from a basin devastated solely by a blast pyroclastic current diminished to background level within five years. These data demonstrate long-term instability of eruption-generated detritus, and show that effective mitigation measures must remain functional for decades.

  14. Interaction of Mount St. Helens' volcanic ash with cells of the respiratory epithelium.

    PubMed

    Adler, K B; Mossman, B T; Butler, G B; Jean, L M; Craighead, J E

    1984-12-01

    Respirable-sized dust from the Mount St. Helens (MSH) eruption of Spring 1980, and minerals similar to the major components of the volcanic ash, were examined comparatively for interactions with epithelial cells of rodent respiratory airways in vitro. MSH dust, Na feldspar, cristobalite, and alpha-quartz, in concentrations of 0.4 to 40 mg/ml, had neither significant effects on mucin release by tracheal explants nor acute toxic effects after exposure for 2 hr. Long-term incubation (1 and 3 weeks) of explants after a 1-hr exposure to MSH dust failed to elicit widespread toxic or proliferative changes in airway epithelial cells. In contrast, long-term exposure to Na feldspar, cristobalite, and alpha-quartz caused significant toxicity to the explants, although metaplastic changes were not observed. Ultrastructural evidence of associations (e.g., phagocytosis) between particulates and respiratory epithelium was not observed. The results of these studies suggest that volcanic ash from MSH interacts minimally with cells of the respiratory mucosa.

  15. Influence of Mount St. Helens volcanic ash on alfalfa growth and nutrient uptake

    SciTech Connect

    Mahler, R.L.

    1984-01-01

    Concern has been expressed that large amounts of volcanic ash from the May 18, 1980 eruption of Mount St. Helens may have created potential nutritional problems associated with forage production in northern Idaho and eastern Washington to the extent that adjustments need to be made in soil test correlation data. The objectives of this greenhouse study were to : (1) determine the effect of varying amounts of volcanic ash mixed into soils of northern Idaho on total alfalfa biomass production, and (2) to determine the effect of various soil/ash mixtures on the nutrient concentrations of P, K, S, Ca, Mg, Mn and Zn in alfalfa. Alfalfa was grown in eight different northern Idaho soils amended with differing levels of volcanic ash (0, 20, 35, 50 and 75%) in the greenhouse. The alfalfa seeds were inoculated and fertilizer P and S were added to all treatments. Total plant biomass and P, K, S, Ca, Mg, Mn and Zn plant concentrations were measured. The eight were pooled for analysis and it was found that increasing amounts of volcanic ash increased alfalfa biomass production. Plant P, S, Ca, Mg and Zn concentrations also increased with increasing levels of ash. Conversely, increasing levels of ash resulted in lower alfalfa tissue K and Mn concentrations. 13 references, 7 figures.

  16. Airborne aerosol measurements in the quiescent plume of Mount St. Helens: September, 1980

    SciTech Connect

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

    1982-09-01

    Atmospheric particulate matter and condensed volatile species were collected in the quiescent plume of Mount St. Helens volcano in Sept. 1980 using air filter systems mounted aboard a NASA turbo-prop P-3 aircraft. Concentrations of 27 elements were determined by instrumental neutron activation analysis and ion chromotagraphy. The volatile elements Cl, Br, F, Zn, W, In, S, Cd, Se, Sb, Hg, As and Au were enriched relative to bulk ash emitted during the earlier eruptions by factors of 50 to 20,000. Particulate S concentrations were approx.3 ..mu..g/m/sup 3/ and accounted for 6% of the total plume sulfur. Gas-phase Hg concentrations were 2.5 to 16 ng/m/sup 3/. Fluxes of elements were estimated by normalizing elemental concentrations to the concurrently measured total sulfur flux. Emission rates vary from 3500 kg/day for particulate Cl to 3 kg/day for Au, with substantial quantities of the enriched elements Zn, As, Hg, Sb, Se, and Cd also being released. Estimated global fluxes of these elements from volcanoes to the atmosphere are in reasonable agreement with other literature estimates.

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

    PubMed

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

    1981-01-01

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

  18. The 1980 eruptions of Mount St. Helens - Physical and chemical processes in the stratospheric clouds

    NASA Technical Reports Server (NTRS)

    Turco, R. P.; Toon, O. B.; Whitten, R. C.; Hamill, P.; Keesee, R. G.

    1983-01-01

    The large and diverse set of observational data collected in the high-altitude plumes of the May 18, May 25, and June 13, 1980 eruptions is organized and analyzed with a view to discerning the processes at work. The data serve to guide and constrain detailed model simulations of the volcanic clouds. For this purpose, use is made of a comprehensive one-dimensional model of stratospheric sulfate aerosols, sulfur precursor gases, and volcanic ash and dust. The model takes into account gas-phase and condensed-phase (heterogeneous) chemistry in the clouds, aerosol nucleation and growth, and cloud expansion. Computational results are presented for the time histories of the gaseous species concentrations, aerosol size distributions, and ash burdens of the eruption clouds. Also investigated are the long-term buildup of stratospheric aerosols in the Northern Hemisphere and the persistent effects of injected chlorine and water vapor on stratospheric ozone. It is concluded that SO2, water vapor, and ash were probably the most important substances injected into the stratosphere by the Mount St. Helens volcano, both with respect to their widespread effects on composition and their effect on climate.

  19. Vegetation patterns 25 years after the eruption of Mount St. Helens, Washington, USA.

    PubMed

    Del Moral, Roger; Lacher, Iara L

    2005-12-01

    In 2004, we surveyed the vegetation on Mount St. Helens to document changes since 1992. We asked how communities differentiate and if they develop predictable relationships with local environments. We sought evidence from links between species and environment and changes in community structure in 271 250-m(2) plots. The habitats of the seven community types (CTs) overlapped broadly. Ordination methods demonstrated weak correlations among species distributions and location, elevation, and surface variables. Comparisons to 1992 by habitat demonstrated a large increase in plant cover and substantial development of vegetation structure. Pioneer species declined while mosses increased proportionately leading to more pronounced dominance hierarchies in most habitats. In Lupinus colonies, dominance declined, and diversity increased due to the increased abundance of formerly rare species. On once barren sites, dominance increased, but diversity changed slightly, which suggested the incipient development of competitive hierarchies. Weak correlations between vegetation and the environment suggested that initially stochastic establishment patterns had not yet been erased by deterministic factors. A vegetation mosaic that is loosely controlled by environmental factors may produce different successional trajectories that lead to alternative stable communities in similar habitats. This result has implications for restoration planning.

  20. Comparative in vitro cytotoxicity of volcanic ashes from Mount St. Helens, El Chichon, and Galunggung.

    PubMed

    Vallyathan, V; Robinson, V; Reasor, M; Stettler, L; Bernstein, R

    1984-01-01

    Dry sedimented volcanic ash samples from each of three widely separated volcanoes of the "Circum Pacific" region have been subjected to mineralogic analysis and in vitro tests for cytotoxicity. The ash samples from the three different volcanoes varied in particle size, surface area, and concentration of silica. Total crystalline silica in the respirable fraction of ashes was 1.5% (Mount St. Helens, Moses Lake); 1.36% (Galunggung, Bandung-1); 1.95% (Gallunggung, Bandung-2); and 1.72% (El Chichon, Tuxtla). Hemolysis as an index of cytotoxicity was measured by in vitro tests on sheep blood erythrocytes and indicated wide differences in hemolytic activity among ash samples. Alveolar macrophage cytosolic (lactate dehydrogenase) and lysosomal (beta-glucuronidase and beta-N-acetyl glucosaminidase) enzymes were measured as an index of cellular integrity following dust exposure. Hemolysis and release of enzymes from alveolar macrophages were greater with volcanic ash from Galunggung (Bandung-1) and El Chichon (Tuxtla) than the other ashes. Although crystalline silica induced an effect similar to volcanic ash from Galunggung (Bandung-1) on the release of enzymes from alveolar macrophages, the hemolytic potency of silica was much greater. Light and electron microscopic observations of dust-exposed alveolar macrophages indicated that the ash particles were readily phagocytized. These results indicate that volcanic ash is moderately cytotoxic and that exposure may lead to overt reactions and the exacerbation of preexisting chronic inflammatory processes.

  1. Mount St. Helens ash fall in the Bull Run watershed, Oregon, May-June 1980

    SciTech Connect

    Shulters, M.V.; Clifton, D.G.

    1980-07-01

    On May 25-26, May 30-June 2, and June 12-13, 1980, strong, high-altitude winds from the north occurred during periods of volcanic-ash eruption at Mount St. Helens in southwestern Washington. As a result, ash fell in the Bull Run watershed, Oregon, some 50 miles to the south, the principal water-supply source for the Portland area. Samples from precipitation collectors and from stream sites in the Bull Run watershed were collected on several dates during May and June 1980. Analyses were made and are tabulated for pH, conductivity, acidity, sulfate, and nitrate plus nitrite. Field pH values of the precipitation ranged from 4.0 to 5.6 pH units and the stream samples from 6.7 to 7.5 units. Particle-size analyses for ash samples collected in the Bull Run watershed and Portland, Oregon, are also shown. Volcanic events, precipitation and high-altitude speeds for northerly winds are given for May 18-June 15, 1980. 6 references, 5 figures, 3 tables.

  2. Mount St. Helens ash from the 18 May 1980 eruption: chemical, physical, mineralogical, and biological properties

    SciTech Connect

    Fruchter, J.S.; Robertson, D.E.; Evans, J.C.

    1980-09-05

    Samples of ash from the 18 May 1980 eruption of Mount St. Helens were collected from several locations in eastern Washington and Montana. The ash was subjected to a variety of analyses to determine its chemical, physical, mineralogical, and biological characteristics. Chemically, the ash samples were of dacitic composition. Particle size data showed bimodal distributions and differed considerably with location. However, all samples contained comparable amounts of particles less than 3.5 micrometers in diameter (respirable fraction). Mineralogically, the samples ranged from almost totally glassy to almost totally crystalline. Crystalline samples were dominated by plagioclase feldspar (andesine) and orthopyroxene (hypersthene), with smaller amounts of titanomagnetite and hornblende. All but one of the samples contained from less than 1% to 3% free crystalline silica (quartz, trydimite, or cristobalite) in both the bulk samples and 1 to 2% in the fractions smaller than 3.5 micrometers. The long-lived natural radionuclide content of the ash was comparable to that of crustal material; however, relatively large concentrations of short-lived radon daughters were present and polonium-210 content was inversely correlated with particle size. In vitro biological tests showed the ash to be nontoxic to alveolar macrophages, which are an important pat of the lungs' natural clearance mechanism. On the basis of a substantial body of data that has shown a correlation between macrophage cytotoxicity and fibrogenicity of minerals, the ash is not predicted to be highly fibrogenic.

  3. Colonization genetics of an animal-dispersed plant (Vaccinium membranaceum) at Mount St Helens, Washington.

    PubMed

    Yang, S; Bishop, J G; Webster, M S

    2008-02-01

    Population founding and spatial spread may profoundly influence later population genetic structure, but their effects are difficult to quantify when population history is unknown. We examined the genetic effects of founder group formation in a recently founded population of the animal-dispersed Vaccinium membranaceum (black huckleberry) on new volcanic deposits at Mount St Helens (Washington, USA) 24 years post-eruption. Using amplified fragment length polymorphisms and assignment tests, we determined sources of the newly founded population and characterized genetic variation within new and source populations. Our analyses indicate that while founders were derived from many sources, about half originated from a small number of plants that survived the 1980 eruption in pockets of remnant soil embedded within primary successional areas. We found no evidence of a strong founder effect in the new population; indeed genetic diversity in the newly founded population tended to be higher than in some of the source regions. Similarly, formation of the new population did not increase among-population genetic variance, and there was no evidence of kin-structured dispersal in the new population. These results indicate that high gene flow among sources and long-distance dispersal were important processes shaping the genetic diversity in this young V. membranaceum population. Other species with similar dispersal abilities may also be able to colonize new habitats without significant reduction in genetic diversity or increase in differentiation among populations.

  4. Impact of mount st. Helens eruption on bacteriology of lakes in the blast zone.

    PubMed

    Staley, J T; Lehmicke, L G; Palmer, F E; Peet, R W; Wissmar, R C

    1982-03-01

    Lakes lying within the blast zone of Mount St. Helens showed dramatic increases in heterotrophic bacterial numbers after the eruption of 18 May 1980. The total microscopic counts of bacteria in some of the most severely affected lakes were more than 10 cells per ml, an order of magnitude above the counts in outlying control lakes. Likewise, the numbers of viable bacteria reached levels of more than 10 cells per ml, compated with fewer than 10 cells per ml in control lakes. The CPS medium used for enumeration provided growth of up to 81.5% of the bacteria during sampling of one of the blast zone lakes. The high numbers of bacteria and the efficacy of the viable enumeration procedure are evidence that the lakes have been transformed rapidly from oligotrophy to eutrophy due to the eruption and its aftermath. Organic material leached from the devastated forest vegetation is thought to be responsible for the enrichment of heterotrophs. Total coliform bacteria were found in all of the blast zone lakes, and some lakes contained fecal coliform bacteria. Klebsiella pneumoniae was the predominant total coliform and was also identified as one of the fecal coliform bacteria, although Escherichia coli was the predominant species in that category. Our data indicate that bacterial populations peaked in the outer blast zone lakes in the summer of 1980 and in most of the inner lakes during the summer of 1981.

  5. Acute effects of volcanic ash from Mount Saint Helens on lung function in children.

    PubMed

    Buist, A S; Johnson, L R; Vollmer, W M; Sexton, G J; Kanarek, P H

    1983-06-01

    To evaluate the acute effects of volcanic ash from Mt. St. Helens on the lung function of children, we studied 101 children 8 to 13 yr of age who were attending a 2-wk summer camp for children with diabetes mellitus in an area where about 1.2 cm of ash had fallen after the June 12, 1980, eruption. The outcome variables used were forced vital capacity, forced expiratory volume in one second, their ratio and mean transit time. Total and respirable dust levels were measured using personal sampling pumps. The children were tested on arrival and twice (early morning [A.M.] and late afternoon [P.M.]) every second or third day during the session. A within-day effect was measured by the P.M./A.M. ratio for the lung function variables; a between-day effect was measured by the change in the P.M. measurements over the 2 wk of camp. We found no strong evidence of either a within-day or a between-day effect on lung function, even in a subgroup of children who had preexisting lung disease or symptoms, despite daytime dust/ash levels that usually exceeded the Environmental Protection Agency's significant harm level for particulate matter.

  6. Mount st. Helens ash from the 18 may 1980 eruption: chemical, physical, mineralogical, and biological properties.

    PubMed

    Fruchter, J S; Robertson, D E; Evans, J C; Olsen, K B; Lepel, E A; Laul, J C; Abel, K H; Sanders, R W; Jackson, P O; Wogman, N S; Perkins, R W; VAN Tuyl, H H; Beauchamp, R H; Shade, J W; Daniel, J L; Erikson, R L; Sehmel, G A; Lee, R N; Robinson, A V; Moss, O R; Briant, J K; Cannon, W C

    1980-09-05

    Samples of ash from the 18 May 1980 eruption of Mount St. Helens were collected from several locations in eastern Washington and Montana. The ash was subjected to a variety of analyses to determine its chemical, physical, mineralogical, and biological characteristics. Chemically, the ash samples were of dacitic composition. Particle size data showed bimodal distributions and differed considerably with location. However, all samples contained comparable amounts of particles less than 3.5 micrometers in diameter (respirable fraction). Mineralogically, the samples ranged from almost totally glassy to almost totally crystalline. Crystalline samples were dominated by plagioclase feldspar (andesine) and orthopyroxene (hypersthene), with smaller amounts of titanomagnetite and hornblende. All but one of the samples contained from less than 1 percent to 3 percent free crystalline silica (quartz, trydimite, or cristobalite) in both the bulk samples and 1 to 2 percent in the fractions smaller than 3.5 micrometers. The long-lived natural radionuclide content of the ash was comparable to that of crustal material; however, relatively large concentrations of short-lived radon daughters were present and polonium-210 content was inversely correlated with particle size. In vitro biological tests showed the ash to be nontoxic to alveolar macrophages, which are an important part of the lungs' natural clearance mechanism. On the basis of a substantial body of data that has shown a correlation between macrophage cytotoxicity and fibrogenicity of minerals, the ash is not predicted to be highly fibrogenic.

  7. Equisetum plants and the cycling of mercury at Mount St. Helens

    SciTech Connect

    Siegel, B.Z.; Siegel, S.M.; Horsky, S.J.

    1984-03-01

    Samples of Equisetum arvense collected in July 1982 at nine stations around Mount St. Helens have increased by 63-158 ppb in mercury content since the last sampling at the same locations in June 1981. Associated soils show little change by comparison. Unlike the highly directional pattern of June 1981, suggestive of the plume vector of the major 1980 eruption, the July 1982 distribution is more diffuse. It seems consistent with a continuous and extended mercury output distributed around the compass by seasonal and local wind variation. Mercury in follow-up samples at four stations in Sept 1982 had decreased 20-91 ppb without significant soil change. The authors propose that these variations are based on a predominat atmospheric source of plant mercury, the episodic character of volcanic mercury emission into the atmosphere, and relatively steady rates of volatilization of mercury from the plants. Calculated loss rates in the field samples agree well with measured rates of mercury release by Equisetum in the laboratory.

  8. GOES weather satellite observations and measurements of the May 18, 1980, Mount St. Helens eruption

    NASA Technical Reports Server (NTRS)

    Holasek, R. E.; Self, S.

    1995-01-01

    We demonstrate the use of Geostationary Operational Environmental Satellite (GOES) images of the May 18, 1980, Mount St. Helens volcanic plume in providing details of the dynamics and changing character of this major explosive eruption. Visible and thermal infrared (IR) data from a sequence of images at 30-min intervals from 0850 to 1720 Local Time (LT) give information on dispersal and plume top temperature. Initial visible and IR images at 0850 show the top of a spreading co-ignimbrite-like umbrella plume and an overshooting column emerging from it, both rising off the ground-hugging pyroclastic gravity flow generated by the opening directed blast. The overshooting column had a minimum temperature significantly colder than local ambient atmosphere, indicating substantial undercooling, and a maximum altitude of 31 +/- 2 km at 0920. This large plume system then formed a high-velocity, radially spreading, gravitationally driven current before becoming advected in the wind field at an average downwind velocity of 29 m/s. Reflectance values from visible GOES data change from lower to higher during periods of transition from darker toned Plinian to lighter toned co-ignimbrite plumes indicating that in this case satellite data resolved changes in eruptive style from plumes with a coarser to a finer dominant particle size.

  9. Potential impact of dust aerosols on the pre-Helene (2006) mesoscale convective vortex

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Sokolik, I. N.; Curry, J. A.

    2011-12-01

    The potential impact of dust aerosols on the early development of Hurricane Helene (2006) was examined using the Weather Research and Forecasting (WRF) and WRF-Chem model. The goal of this study is to examine the extent to which dust aerosols can influence the intensity, track, and structure of a developing TC through the microphysical and radiation processes. Remote sensing observations from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), CloudSat, Moderate Resolution Imaging Spectroradiometer (MODIS), and Tropical Rainfall Measuring Mission (TRMM) were utilized to examine the distributions and characteristics of dust particles, hydrometeors, cloud top temperature, latent heat release and precipitation, as well as to constrain and evaluate the model simulations. The WRF simulations were conducted by implementing an ice nucleation parameterization accounting for the deliquescent heterogeneous freezing (DHF) mode. The DHF mode refers to the freezing process for internally mixed aerosols with soluble and insoluble species that can serve as both cloud condensation nuclei (CCN) and ice nuclei (IN), such as dust. Simulations showed the tendency of DHF mode to promote ice formation at lower altitudes in strong updraft cores, increase the local latent heat release, and produce more low clouds and less high clouds. Further more, a series of WRF-Chem simulations were conducted, which includes aerosol emission scheme, a radiative transfer scheme accounting for aerosol optical properties, and a dual moment microphysics scheme that will account for environmental aerosols as nuclei. Differences between the results from WRF and WRF-Chem simulations were examined.

  10. Impact of dust aerosols on Hurricane Helene's early development through the deliquescent heterogeneous freezing mode

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Sokolik, I. N.; Curry, J. A.

    2011-05-01

    An ice nucleation parameterization accounting for the deliquescent heterogeneous freezing (DHF) mode was implemented into the Weather Research Forecast (WRF) model. The DHF mode refers to the freezing process for internally mixed aerosols with soluble and insoluble species that can serve as both cloud condensation nuclei (CCN) and ice nuclei (IN), such as dust. A modified version of WRF was used to examine the effect of Saharan dust on the early development of Hurricane Helene (2006) via acting as CCN and IN. The WRF simulations showed the tendency of DHF mode to promote ice formation at lower altitudes in strong updraft cores, increase the local latent heat release, and produce more low clouds and less high clouds. The inclusion of dust acting as CCN and IN through the DHF mode modified the storm intensity, track, hydrometeor distribution, cloud top temperature (hence the storm radiative energy budget), and precipitation and latent heat distribution. However, changes in storm intensity, latent heating rate, and total precipitation exhibit nonlinear dependence on the dust concentration. Improvement in the representation of atmospheric aerosols and cloud microphysics has the potential to contribute to better prediction of tropical cyclone development.

  11. Changes in the organic material in lakes in the blast zone of Mount St. Helens, Washington

    USGS Publications Warehouse

    McKnight, Diane M.; Klein, John M.; Wissmar, Robert C.

    1984-01-01

    During several periods of volcanic-ash eruption at Mount St. Helens, Wash., (March 30, May 25-26, May 30-June 2, and June 12-13, 1980) strong winds from the north occurred at high altitudes. As a result, the volcanic ash fell some 50 miles to the south in the Bull Run watershed, the principal water-supply source for the metropolitan area of Portland, Oreg. Water samples collected from three stream sites within the watershed were compared with samples collected during the same season in previous years. No detectable changes were noted in chemical characteristics. Precipitation samples collected immediately after the June 12-13 ash fall ranged in specific conductance from 20 to 41 micromhos per centimeter at 25C and in pH from 4.0 to 4.3 pH units. Stream samples collected during the May-June period ranged in specific conductance from 18 to 28 micromhos per centimeter at 25C and in pH from 6.7 to 7.5 pH units. Volcanic-ash samples were collected and analyzed for particle size, chemical composition, and weight. Significant differences in particle size of ash were found in samples from two separate eruptions. (USGS)

  12. Helen Primrose LeVesconte: occupational therapy clinician, educator, and maker of history.

    PubMed

    Friedland, Judith; Rais, Hadassah

    2005-06-01

    The Canadian history of our profession is not well known and our identity is thought to suffer as a result. Helen Primrose LeVesconte (7896-1982) is one pioneer in our development whose story has not been told. Our purpose is to explore LeVesconte's life and work in order to expand knowledge of our roots and thereby strengthen our identity. Using interpretive biography methods we draw on LeVesconte's own writings, articles written about her, and archival documents to describe turning point moments in her life and to display meaningful patterns in her work. LeVesconte's work as a clinician and her role and reputation as an educator, show her to have been a strong and visionary leader. Her views on the client's role, the importance of the therapist-client relationship, prevention, community-based programs, and vocational rehabilitation are of particular interest. Because LeVesconte educated over 1,850 students while director of the occupational therapy program at the University of Toronto, her influence has been felt throughout the country. Her perspective is compared to current practice; and questions are raised as to aspects of her legacy and philosophy that might now be reconsidered.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  14. Ash loading and insolation at Hanford, Washington during and after the eruption of Mount St. Helens

    NASA Technical Reports Server (NTRS)

    Laulainen, N. S.

    1982-01-01

    The effects of volcanic ash suspended in the atmosphere on the incident solar radiation was monitored at the Hanford Meteorological Station (HMS) subsequent to the major eruption of Mount St. Helens on May 18, 1980. Passage of the ash plume over Hanford resulted in a very dramatic decrease of solar radiation intensity to zero. A reduction in visibility to less than 1 km was observed, as great quantities of ash fell out of the plume onto the ground. Ash loading in the atmosphere remained very high for several days following the eruption, primarily as a result of resuspension from the surface. Visibilities remained low (2 to 8 km) during this period. Estimates of atmospheric turbidity were made from the ratio of diffuse-to-direct solar radiation; these turbidities were used to estimate extinction along a horizontal path, a quantity which can be related to visibility. Comparisons of observed and estimated visibilities were very good, in spite of the rather coarse approximations used in the estimates. Atmospheric clarity and visibility improved to near pre-eruption conditions following a period of rain showers. The diffuse-to-direct ratio of solar radiation provided a useful index for estimating volcanic ash loading of the atmosphere.

  15. Hydrothermal circulation at Mount St. Helens determined by self-potential measurements

    USGS Publications Warehouse

    Bedrosian, P.A.; Unsworth, M.J.; Johnston, M.J.S.

    2007-01-01

    The distribution of hydrothermal circulation within active volcanoes is of importance in identifying regions of hydrothermal alteration which may in turn control explosivity, slope stability and sector collapse. Self-potential measurements, indicative of fluid circulation, were made within the crater of Mount St. Helens in 2000 and 2001. A strong dipolar anomaly in the self-potential field was detected on the north face of the 1980-86 lava dome. This anomaly reaches a value of negative one volt on the lower flanks of the dome and reverses sign toward the dome summit. The anomaly pattern is believed to result from a combination of thermoelectric, electrokinetic, and fluid disruption effects within and surrounding the dome. Heat supplied from a cooling dacite magma very likely drives a shallow hydrothermal convection cell within the dome. The temporal stability of the SP field, low surface recharge rate, and magmatic component to fumarole condensates and thermal waters suggest the hydrothermal system is maintained by water vapor exsolved from the magma and modulated on short time scales by surface recharge. ?? 2006 Elsevier B.V. All rights reserved.

  16. Emplacement of a silicic lava dome through a crater glacier: Mount St Helens, 2004-06

    USGS Publications Warehouse

    Walder, J.S.; LaHusen, R.G.; Vallance, J.W.; Schilling, S.P.

    2007-01-01

    The process of lava-dome emplacement through a glacier was observed for the first time after Mount St Helens reawakened in September 2004. The glacier that had grown in the crater since the cataclysmic 1980 eruption was split in two by the new lava dome. The two parts of the glacier were successively squeezed against the crater wall. Photography, photogrammetry and geodetic measurements document glacier deformation of an extreme variety, with strain rates of extraordinary magnitude as compared to normal alpine glaciers. Unlike normal temperate glaciers, the crater glacier shows no evidence of either speed-up at the beginning of the ablation season or diurnal speed fluctuations during the ablation season. Thus there is evidently no slip of the glacier over its bed. The most reasonable explanation for this anomaly is that meltwater penetrating the glacier is captured by a thick layer of coarse rubble at the bed and then enters the volcano's groundwater system rather than flowing through a drainage network along the bed.

  17. Mount St. Helens eruptions: the acute respiratory effects of volcanic ash in a North American community.

    PubMed

    Baxter, P J; Ing, R; Falk, H; Plikaytis, B

    1983-01-01

    After the May 18, 1980 volcanic eruption of Mount St. Helens, increases were observed in the number of patients who, because of asthma or bronchitis, sought medical care at emergency rooms of major hospitals in areas of ashfall. An interview study of 39 asthma and 44 bronchitis patients who became sick during the 4 wk following the eruption and who attended the emergency rooms of two major hospitals in Yakima, Washington, and of healthy matched controls indicated that a history of asthma, and possibly of bronchitis, were risk factors for contracting respiratory problems. The interview study also indicated that the main exacerbating factor was the elevated level of airborne total suspended particulates (in excess of 30,000 micrograms/m3) after the eruption. An interview study of 97 patients who had chronic lung disease and who lived in the same area as the above-mentioned patients, but who did not go to a hospital, showed that the ashfall exacerbated the condition in about one-third of these. Emergency planners and their geologist advisers should be aware that special preventive measures are justified for people with a history of asthma or chronic lung disease who live in communities at risk to volcanic ashfalls.

  18. Chan-Yu-Bao-Yuan-Tang and 5-fluorouracil synergistically induce apoptosis by means of the caspase-3 signaling pathway in lung and cervical cancer cells.

    PubMed

    Zeng, Fang; Liu, Xiaoguang; Li, Yuncheng; Chen, Gang; Wang, Yekai; Zhou, Shiquan; Zhu, Wangyu; Huang, Yanyan; Zhou, Jiehang; Li, Shibo; Zhang, Yongkui

    2011-01-01

    Previous clinical studies have shown the safety and efficacy of the traditional Chinese medicinal herbal aqueous extract Chan-Yu-Bao-Yuan-Tang (CYBYT) for the treatment of lung and cervical cancer patients. Used in combination with 5-fluorouracil (5-Fu), CYBYT has been observed to be particularly effective in cancer treatment. Herein, the combined anticancer effect and the underlying mechanisms of 5-Fu and CYBYT in the human lung cancer cell line A549 and the human cervical cancer cell line HeLa were investigated in vitro. The MTT assay, Annexin V-FITC staining and Western blotting were applied to identify cell viability, the stages of apoptosis and the expression of signaling proteins, respectively. The results indicated that CYBYT and 5-Fu, alone or in combination, significantly inhibited proliferation and induced marked apoptosis in A549 and HeLa cells, but had no significant inhibitory effects on normal human IMR-90 fibroblasts. The rate of mid and late apoptosis or necrosis was greater after 5-Fu treatment compared to treatment with CYBYT or the combination of agents; however, the early apoptotic rate showed opposite results. CYBYT and 5-Fu, alone or in combination, up-regulated cleaved caspase-3 expression in a time-dependent manner, with CYBYT being more effective than 5-Fu. Taken together, our data show that the pro-apoptotic activity of the two-drug combination was much stronger than that of CYBYT or 5-Fu alone; CYBYT combined with 5-Fu had synergistic effects at lower concentrations and promoted apoptosis, while the combined treatment also decreased the cytotoxic side effects of 5-Fu.

  19. Timing of degassing and plagioclase growth in lavas erupted from Mount St. Helens, 2004-2005, from 210Po-210Pb-226Ra disequilibria: Chapter 37 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Reagan, Mark K.; Cooper, Kari M.; Pallister, John S.; Thornber, Carl R.; Wortel, Matthew; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    Disequilibrium between 210Po, 210Pb, and 226Ra was measured on rocks and plagioclase mineral separates erupted during the first year of the ongoing eruption of Mount St. Helens. The purpose of this study was to monitor the volatile fluxing and crystal growth that occurred in the weeks, years, and decades leading up to eruption. Whole-rock samples were leached in dilute HCl to remove 210Po precipitated in open spaces. Before leaching, samples had variable initial (210Po) values, whereas after leaching, the groundmasses of nearly all juvenile samples were found to have had (210Po) ≈ 0 when they erupted. Thus, most samples degassed 210Po both before and after the magmas switched from open- to closed-system degassing. All juvenile samples have (210Pb)/(226Ra) ratios within 2 δ of equilibrium, suggesting that the magmas involved in the ongoing eruption did not have strong, persistent fluxes of 222Rn in or out of magmas during the decades and years leading to eruption. These equilibrium values also require a period of at least a century after magma generation and the last significant differentiation of the Mount St. Helens dacites. Despite this, the elevated (210Pb)/(226Ra) value measured in a plagioclase mineral separate from lava erupted in 2004 suggests that a significant proportion of this plagioclase grew within a few decades of eruption. The combined dataset suggests that for most 2004-5 lavas, the last stage of open-system degassing of the dacite magmas at Mount St. Helens is confined to the period between 1-2 years and 1-2 weeks before eruption, whereas plagioclase large enough to be included in the mineral separate grew around the time of the 1980s eruption or earlier.

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

    USGS Publications Warehouse

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

    2008-01-01

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

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

    USGS Publications Warehouse

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

    2008-01-01

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

  2. GeoGirls: A Geology and Geophysics Field Camp for Middle School Girls at Mount St. Helens

    NASA Astrophysics Data System (ADS)

    Samson, C.; Allstadt, K.; Melander, S.; Groskopf, A.; Driedger, C. L.; Westby, E.

    2015-12-01

    The August 2015 GeoGirls program was a project designed to inspire girls to gain an appreciation and enthusiasm for Earth sciences using Mount St. Helens as an outdoor volcanic laboratory. Occupations in the field of science and engineering tend to be held by more males than females. One way to address this is to introduce girls to possible opportunities within the geosciences and encourage them to learn more about the dynamic environment in which they live. In 2015, the GeoGirls program sought to accomplish this goal through organizing a five day-long field camp for twenty middle school-aged girls, along with four high school-aged mentors and two local teachers. This group explored Mount St. Helens guided by female scientists from the USGS Cascade Volcano Observatory (CVO), the Mount St. Helens Institute (MSHI), UNAVCO, Boise State, Georgia Tech, University of Washington and Oregon State University. To introduce participants to techniques used by volcanologists, the girls participated in hands-on experiments and research projects focusing on seismology, GPS, terrestrial lidar, photogrammetry, water and tephra. Participants also learned to collect samples, analyze data and use microscopes. Through this experience, participants acquired strategies for conducting research by developing hypotheses, making observations, thinking critically and sharing their findings with others. The success of the GeoGirls program was evaluated by participant and parent survey questionnaires, which allowed assessment of overall enthusiasm and interest in pursuing careers in the geosciences. The program was free to participants and was run jointly by MSHI and CVO and funded by NSF, the American Association of University Women, the Association for Women Geoscientists, the Association of Environmental & Engineering Geologists and private donors. The program will run again in the summer of 2016.

  3. How useful is the Helen Keller food frequency chart in the determination of the vitamin A status in pregnancy?

    PubMed

    Eigbefoh, J O; Okpere, E E; Ande, B; Asonye, C

    2005-02-01

    Vitamin A deficiency sub clinical or overt, is associated with adverse maternal, fetal and neonatal outcome. This is also true for an excess of vitamin A. The challenge in pregnancy is to detect sub clinical vitamin A deficiency in patients for whom supplements or dietary manipulation will be of benefit. This was a cross sectional case controlled study at the University of Benin Teaching Hospital to compare the Helen Keller Food Frequency Chart with biochemical methods in the determination of vitamin A status in pregnancy. Data was collected from Antenatal patients (142). Using serum Biochemistry three categories of patient were recognized. Patients with normal vitamin A levels (N=100 women with blood vitamin A within two standard deviation of the mean) Twenty-four women (24) had low vitamin A levels (N=24, patients with blood vitamin A level at less than 2 standard deviation below the mean). Eighteen patients (18) had high vitamin A levels (patients with blood vitamin A levels at greater than two standard deviation above the mean). All recruited patients had a dietary assessment using the Helen Keller Food Frequency Chart. The Helen Keller Food Frequency Chart (HKFFC) was found to have a high degree of sensitivity (74.5%) and a high specificity (75%) in detection of patients with vitamin A deficiency. The positive predictive value was 93.62%. The low negative predictive rate of 37.5% however implies that a positive test is more important than a negative test. The HKFFC was unable to differentiate patients with normal or high vitamin A levels. Dietary assessment with the HKFFC is a cheap effective method to detect sub clinical vitamin A deficiency in pregnancy. It is an easy cost effective screening tool to select patients for whom dietary manipulation and or vitamin A supplementation may be beneficial.

  4. Local Earthquake P-wave Tomography at Mount St. Helens with the iMUSH Broadband Array

    NASA Astrophysics Data System (ADS)

    Ulberg, C. W.; Creager, K. C.; Moran, S. C.; Abers, G. A.; Crosbie, K.; Crosson, R. S.; Denlinger, R. P.; Thelen, W. A.; Hansen, S. M.; Schmandt, B.; Kiser, E.; Levander, A.; Bachmann, O.

    2016-12-01

    We deployed 70 broadband seismometers in the summer of 2014 to image the seismic velocity structure beneath Mount St. Helens (MSH), Washington, as part of the collaborative imaging Magma Under St. Helens (iMUSH) project. Our goal is to illuminate the MSH magmatic system by integrating all portions of the iMUSH experiment, including active- and passive-source tomography, ambient-noise tomography, seismicity, receiver functions, magnetotellurics, and petrology. The broadband array has a diameter of 100 km centered on MSH with an average station spacing of 10 km, and was deployed through summer 2016. It is augmented by dozens of permanent stations in the area. We determine P-wave arrival times and also incorporate picks from the permanent network. There were more than 250 local events during the first year of iMUSH broadband recording, which have provided over 11,000 high-quality arrival times. The iMUSH experiment included 23 active shots in 2014 that were recorded with good signal-to-noise ratios across the entire array. Direct raypaths from local earthquakes and active shots reach 15-20 km depth beneath MSH. We use the program struct3DP to iteratively invert travel times to obtain a 3-D seismic velocity model and relocate hypocenters. Travel times are computed using a 3-D eikonal-equation solver. We are expanding our analysis to include S-wave arrivals from local events. The preliminary 3-D model shows low P-wave speeds along the St. Helens seismic zone, striking NNW-SSE of MSH from near the surface to where we lose resolution at 15-20km depth. This seismic zone coincides with a sharp boundary in Moho reflectivity that has been interpreted as the eastern boundary of a serpentinized mantle wedge (Hansen et al, 2016, submitted). We speculate that the seismic zone and low wave speeds are related to fluids rising from the eastern boundary of the wedge.

  5. Experimental phase equilibria of a Mount St. Helens rhyodacite: a framework for interpreting crystallization paths in degassing silicic magmas

    NASA Astrophysics Data System (ADS)

    Riker, Jenny M.; Blundy, Jonathan D.; Rust, Alison C.; Botcharnikov, Roman E.; Humphreys, Madeleine C. S.

    2015-07-01

    We present isothermal (885 °C) phase equilibrium experiments for a rhyodacite from Mount St. Helens (USA) at variable total pressure (25-457 MPa) and fluid composition (XH2Ofl = 0.6-1.0) under relatively oxidizing conditions (NNO to NNO + 3). Run products were characterized by SEM, electron microprobe, and SIMS. Experimental phase assemblages and phase chemistry are consistent with those of natural samples from Mount St. Helens from the last 4000 years. Our results emphasize the importance of pressure and melt H2O content in controlling phase proportions and compositions, showing how significant textural and compositional variability may be generated in the absence of mixing, cooling, or even decompression. Rather, variations in the bulk volatile content of magmas, and the potential for fluid migration relative to surrounding melts, mean that magmas may take varied trajectories through pressure-fluid composition space during storage, transport, and eruption. We introduce a novel method for projecting isothermal phase equilibria into CO2-H2O space (as conventionally done for melt inclusions) and use this projection to interpret petrological data from Mount St. Helens dacites. By fitting the experimental data as empirical functions of melt water content, we show how different scenarios of isothermal magma degassing (e.g., water-saturated ascent, vapor-buffered ascent, and vapor fluxing) can have quite different textural and chemical consequences. We explore how petrological data might be used to infer degassing paths of natural magmas and conclude that melt CO2 content is a much more useful parameter in this regard than melt H2O.

  6. Identifying Water on Mt. Baker and Mt. St. Helens, WA with Geophysics: Implications for Volcanic Landslide Hazards

    NASA Astrophysics Data System (ADS)

    Finn, C.; Bedrosian, P.; Wisniewski, M.; Deszcz-Pan, M.

    2015-12-01

    Groundwater position, abundance, and flow rates within a volcano affect the transmission of fluid pressure, transport of mass and heat and formation of mechanically weak hydrothermal alteration influencing the stability of volcanoes. In addition, eruptions can shatter volcanic rocks, weakening the edifice. Helicopter magnetic and electromagnetic (HEM) data collected over Mt. Baker and Mt. St. Helens volcanoes reveal the distribution of water, shattered volcanic rocks and hydrothermal alteration essential to evaluating volcanic landslide hazards. These data, combined with geological mapping and rock property measurements, indicate the presence of localized <100 m thick zones of water-saturated hydrothermally altered rock beneath Sherman Crater and the Dorr Fumarole Fields at Mt. Baker. Nuclear magnetic resonance data indicate that the hydrothermal clays contain ~50% bound water with no evidence for free water ponded beneath the ice. The HEM data suggest water-saturated fresh volcanic rocks from the surface to the detection limit (~100 m) over the entire summit of Mt. Baker (below the ice). A 50-100 m thick high resistivity layer (>1500 ohm-m) corresponding to domes, debris avalanche, volcanic rocks and glaciers mantles the crater at Mt. St. Helens. Shallow low resistivity layers corresponding to fresh, cold water and hot brines are observed below the high resistivity surface in EM data. Shallow ground water mainly concentrates in shattered dome material in the crater of Mt. St. Helens. Aeromagnetic data indicate the location of basalts sandwiched between debris avalanche deposits and shattered dome material. The combination of the EM and magnetic data help map the location of the shattered dome material that is considered to be the failure surface for the 1980 debris avalanche. The EM data image the regional groundwater table near the base of the volcano. The geophysical identification of groundwater and weak layers constrain landslide hazards assessments.

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

    SciTech Connect

    Fehler, M.; Chouet, B.

    1982-01-01

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

  8. Magma reservoirs from the upper crust to the Moho inferred from high-resolution Vp and Vs models beneath Mount St. Helens

    NASA Astrophysics Data System (ADS)

    Kiser, E.; Palomeras, I.; Levander, A.; Zelt, C. A.; Harder, S. H.; Schmandt, B.; Hansen, S. M.; Creager, K. C.; Ulberg, C. W.

    2015-12-01

    Seismic investigations following the 1980 eruption of Mount St. Helens have led to a detailed model of the magmatic and tectonic structure directly beneath the volcano. These studies suffer from limited resolution below ~10 km, making it difficult to estimate the volume of the shallow magma reservoir beneath the volcano, the regions of magma entry into the lower crust, and the connectivity of this magma system throughout the crust. The latter is particularly interesting as one interpretation of the Southern Washington Cascades Conductor (SWCC) suggests that the Mount St Helens and Mount Adams volcanic systems are connected in the crust (Hill et al., 2009). The multi-disciplinary iMUSH (imaging Magma Under St. Helens) project is designed to investigate these and other fundamental questions associated with Mount St. Helens. Here we present the first high-resolution 2D Vp and Vs models derived from travel-time data from the iMUSH 3D active-source seismic experiment. Significant lateral heterogeneity exists in both the Vp and Vs models. Directly beneath Mount St. Helens we observe a high Vp/Vs body, inferred to be the upper/middle crustal magma reservoir, between 4 and 13 km depth. Southeast of this body is a low Vp column extending from the Moho to approximately 15 km depth. A cluster of low frequency events, typically associated with injection of magma, occurs at the northwestern boundary of this low Vp column. Much of the recorded seismicity between the shallow high Vp/Vs body and deep low Vp column took place in the months preceding and hours following the May 18, 1980 eruption. This may indicate a transient migration of magma between these two reservoirs associated with this eruption. Outside of the inferred magma bodies that feed Mount St. Helens, we observe several other interesting velocity anomalies. In the lower crust, high Vp features bound the low Vp column. One explanation for these features is the presence of lower crustal cumulates associated with

  9. Measurements of the imaginary part of the refractive index between 300 and 700 nanometers for mount st. Helens ash.

    PubMed

    Patterson, E M

    1981-02-20

    The absorption properties, expressed as a wavelength-dependent imaginary index of refraction, of the Mount St. Helens ash from the 18 May 1980 eruption were measured between 300 and 700 nanometers by diffuse reflectance techniques. The measurements were made for both surface and stratospheric samples. The stratospheric samples show imaginary index values that decrease from approximately 0.01 to 0.02 at 300 nanometers to about 0.0015 at 700 nanometers. The surface samples show less wavelength variation in imaginary refractive index over this spectral range.

  10. A comparison of thermal observations of mount st. Helens before and during the first week of the initial 1980 eruption.

    PubMed

    Lawrence, W S; Qamar, A; Moore, J; Kendrick, G

    1980-09-26

    Before and during the first week of the March-April 1980 eruptions of Mount St. Helens, Washington, infrared thermal surveys were conducted to monitor the thermal activity of the volcano. The purpose was to determine if an increase in thermal activity had taken place since an earlier airborne survey in 1966. Nine months before the eruption there was no evidence of an increase in thermal activity. The survey during the first week of the 1980 eruptions indicated that little or no change in thermal activity had taken place up to 4 April. Temperatures of ejected ash and steam were low and never exceeded 15 degrees C directly above the vent.

  11. Composition of the mount st. Helens ashfall in the moscow-pullman area on 18 may 1980.

    PubMed

    Hooper, P R; Herrick, I W; Laskowski, E R; Knowles, C R

    1980-09-05

    Mineralogical and chemical analyses of the ashfall from Mount St. Helens on 18 May 1980 indicate that there were two distinct ashes. The early dark ash is composed principally of plagioclase and lithic fragments of plagioclase and glass with titanium-rich magnetite and some basaltic hornblende and orthopyroxene. The later pale ash, four-fifths by weight of the whole fallout, is 80 percent glass with plagioclase as the principal crystalline phase. Quartz and potassium feldspar are rare to absent in both ashes. Chemical analyses of nine ash fractions and of the glass in each type emphasize the differences between the two ash types and their chemical homogeneity.

  12. Measurements of the imaginary part of the refractive index between 300 and 700 nanometers for Mount St. Helens ash

    SciTech Connect

    Patterson, E.M.

    1981-01-01

    The absorption properties, expressed as a wavelength-dependent imaginary index of refraction, of the Mount St. Helens ash from the 18 May 1980 eruption were measured between 300 and 700 nanometers by diffuse reflectance techniques. The measurements were made for both surface and stratospheric samples. The stratospheric samples show imaginary index values that decrease from approximately 0.01 to 0.02 at 300 nanometers to about 0.0015 at 700 nanometers. The surface samples show less wavelength variation in imaginary refractive index over this spectral range.

  13. Trace metals in the Columbia River Estuary following the 18 May 1980 eruption of Mount St. Helens

    SciTech Connect

    Riedel, G.F.; Wilson, S.L.; Holton, R.L.

    1984-10-01

    Dissolved and suspended concentrations of cadmium, copper, iron, manganese, nickel, lead, and zinc were measured in the Columbia River Estuary following the 18 May 1980 eruption of Mount St. Helens. Soluble concentrations of these trace elements were not substantially elevated by the influx of volcanic ash and mud into the estuary during this period, except for somewhat higher than usual concentrations of manganese and copper. A laboratory experiment indicates that manganese leached from volcanic debris in fresh water and in the transition from fresh to slightly saline water probably caused the elevated Mn leaching from the material into fresh water.

  14. Amphibole trace elements as indicators of magmatic processes at Mount St. Helens

    NASA Astrophysics Data System (ADS)

    Hampel, T. R.; Rowe, M. C.; Kent, A.; Thornber, C. R.

    2011-12-01

    Amphibole has the capability of incorporating a wide variety of trace elements resulting from a range of magmatic processes. Prior studies have used trace elements such as Li and Cu in amphibole to investigate volatile mobility associated with magma ascent regarding the 2004-2008 eruption of Mount St. Helens (Rowe et al. 2008). In order to investigate magmatic processes associated with the 2004-2008 eruption of Mount St. Helens we have measured a range of fluid-mobile trace elements in conjunction with major element compositions of amphibole phenocrysts in dacite lava. Major elements and volatiles (Cl, F) were measured by electron microprobe analysis at Washington State University and trace elements (Li, Sc, Co, Cu, Zn, Sr, Y, Zr, Mo, Ag, Sn, Sb, Te, Ba, Ce, W, and Pb) were analyzed by laser ablation (LA)-ICP-MS at Oregon State University. Amphibole crystallization temperatures were calculated after Ridolfi et al. (2010). Core to rim transects were measured by electron microprobe to evaluate volatile concentrations and temperature profiles across individual phenocrysts. Core temperatures from 17 days and 226 days post eruption are consistently hotter than the rim temperatures 997 to 881 degrees C, respectively. Amphiboles from the end of the eruption (811 days post eruption) appear to be more complex, with phenocrysts having both increasing and decreasing temperatures toward the rims. The overall calculated temperature range of the amphiboles at the end of the eruption is 1022 to 919 degrees C. There is much diversity in the concentrations of Li and Cu within the phenocrysts in both the samples and throughout the eruption. Concentrations steadily increase in the beginning of the eruption then drop dramatically toward the middle, slowly increase toward the end eruption. Overall concentrations of Sr, Sb, Co, Sn, Mo, Ba, Ce, Sc, and Y do not change over the course of the eruption but do vary sample to sample. Preliminary data for Zn, Sb, Ag, and W suggest the

  15. Hydrometeor-enhanced tephra sedimentation: Constraints from the 18 May 1980 eruption of Mount St. Helens

    USGS Publications Warehouse

    Durant, A.J.; Rose, William I.; Sarna-Wojcicki, A. M.; Carey, Steven; Volentik, A.C.M.

    2009-01-01

    Uncertainty remains on the origin of distal mass deposition maxima observed in many recent tephra fall deposits. In this study the link between ash aggregation and the formation of distal mass deposition maxima is investigated through reanalysis of tephra fallout from the Mount St. Helens 18 May 1980 (MSH80) eruption. In addition, we collate all the data needed to model distal ash sedimentation from the MSH80 eruption cloud. Four particle size subpopulations were present in distal fallout with modes at 2.2 ??, 4.2 ??, 5.9 ??, and 8.3 ??. Settling rates of the coarsest subpopulation closely matched predicted single-particle terminal fall velocities. Sedimentation of particles <100 ??m was greatly enhanced, predominantly through aggregation of a particle subpopulation with modal diameter 5.9 ?? 0.2 ?? (19 ?? 3 ??m). Mammatus on the MSH80 cloud provided a mechanism to transport very fine ash particles, with predicted atmospheric lifetimes of days to weeks, from the upper troposphere to the surface in a matter of hours. In this mechanism, ash particles initiate ice hydrometeor formation high in the troposphere. Subsequently, the volcanic cloud rapidly subsides as mammatus develop from increased particle loading and cloud base sublimation. Rapid fallout occurs as the cloud passes through the melting level in a process analogous to snowflake aggregation. Aggregates sediment en masse and form the distal mass deposition maxima observed in many recent volcanic ash fall deposits. This work provides a data resource that will facilitate tephra sedimentation modeling and allow model intercomparisons. Copyright 2009 by the American Geophysical Union.

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

    USGS Publications Warehouse

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

    2008-01-01

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

  17. Mount St. Helens: Controlled-source audio-frequency magnetotelluric (CSAMT) data and inversions

    USGS Publications Warehouse

    Wynn, Jeff; Pierce, Herbert A.

    2015-01-01

    The apparent conductivity (or its inverse, apparent resistivity) measured by a geoelectrical system is caused by several factors. The most important of these are water-filled rock porosity and the presence of water-filled fractures; however, rock type and minerals (for instance, sulfides and clay content) also contribute to apparent conductivity. In situations with little recharge (for instance, in arid regions), variations in ionic content of water occupying pore space and fractures sampled by the measurement system must also be factored in (Wynn, 2006). Variations in ionic content may also be present in hydrothermal fluids surrounding volcanoes in wet regions. In unusual cases, temperature may also affect apparent conductivity (Keller, 1989; Palacky, 1989). There is relatively little hydrothermal alteration (and thus fewer clay minerals that might add to the apparent conductivity) in the eruptive products of Mount St. Helens (Reid and others, 2010), so conductors observed in the Fischer, Occam, and Marquardt inversion results later in this report are thus believed to map zones with significant water content. Geoelectrical surveys thus have the potential to reveal subsurface regions with significant groundwater content, including perched and regional aquifers. Reid and others (2001) and Reid (2004) have suggested that groundwater involvement may figure in both the scale and the character of some if not all volcanic edifice collapse events. Ongoing research by the U.S. Geological Survey (USGS) and others aims to better understand the contribution of groundwater to both edifice pore pressure and rock alteration as well as its direct influence on eruption processes by violent interaction with magma (Schmincke, 1998).

  18. Investigations of sacrificial and plasma mirrors on the HELEN laser CPA beam

    NASA Astrophysics Data System (ADS)

    Andrew, James E.; Comley, Andrew J.

    2007-01-01

    The performance of sacrificial and plasma mirrors has been investigated on the HELEN laser chirped pulse amplification [CPA] beam line. Sacrificial mirrors are initially highly reflective surfaces that degrade during the course of a pulsed laser experiment. They are being considered for protecting the off axis parabolic surfaces used to focus CPA lasers from plasma physics target generated debris and shrapnel. Plasma mirrors are initially low reflectivity surfaces that transmit low intensity beams but produce a reflecting plasma surface during the course of the laser pulse. They are being investigated to prevent prepulse effects in plasma physics experiments and increase the contrast ratio of the incident laser beam.The sacrificial mirrors were operated at 45 degrees angle of incidence and an average input beam diameter of ~14 mm with intensities in the range 8 TW/cm2 to 44 TW/cm2. Dielectric protected silver and gold coatings as well as dielectric multi layers were studied as the mirror surfaces for directing all of the short pulse [500fs] laser beams onto tantalum foil targets of 10 microns thickness. Proton emissions from the foils monitored by radiochromic film were used to evaluate the beam irradiance achieved from the mirror surfaces. Glass witness plates were used to evaluate debris and shrapnel emissions from the mirror surfaces, the diagnostics and the target foils. The plasma mirrors were operated in a similar configuration but with beam diameters of ~8mm and irradiances of 57 TW/cm2 to 235 TW/cm2. Uncoated and sol gel anti-reflection coated fused silica were used as the high intensity mirror surfaces. The influence of surface coating on laser damage morphology will be described as well as post shot inspection of debris distributions.

  19. The 2004–2008 dome-building eruption at Mount St. Helens, Washington: Epilogue

    USGS Publications Warehouse

    Dzurisin, Daniel; Moran, Seth C.; Lisowski, Michael; Schilling, Steve P.; Anderson, Kyle R.; Werner, Cynthia A.

    2015-01-01

    The 2004–2008 dome-building eruption at Mount St. Helens ended during winter 2007–2008 at a time when field observations were hampered by persistent bad weather. As a result, recognizing the end of the eruption was challenging—but important for scientists trying to understand how and why long-lived eruptions end and for public officials and land managers responsible for hazards mitigation and access restrictions. In hindsight, the end of the eruption was presaged by a slight increase in seismicity in December 2007 that culminated on January 12–13, 2008, with a burst of more than 500 events, most of which occurred in association with several tremor-like signals and a spasmodic burst of long-period earthquakes. At about the same time, a series of regular, localized, small-amplitude tilt events—thousands of which had been recorded during earlier phases of the eruption—came to an end. Thereafter, seismicity declined to 10–20 events per day until January 27–28, when a spasmodic burst of about 50 volcano-tectonic earthquakes occurred over a span of 3 h. This was followed by a brief return of repetitive “drumbeat” earthquakes that characterized much of the eruption. By January 31, however, seismicity had declined to 1–2 earthquakes per day, a rate similar to pre-eruption levels. We attribute the tilt and seismic observations to convulsive stagnation of a semisolid magma plug in the upper part of the conduit. The upward movement of the plug ceased when the excess driving pressure, which had gradually decreased throughout the eruption as a result of reservoir deflation and increasing overburden from the growing dome, was overcome by increasing friction as a result of cooling and crystallization of the plug.

  20. Cessation of the 2004-2008 Dome-Building Eruption at Mount St. Helens, Washington

    NASA Astrophysics Data System (ADS)

    Moran, S. C.; Dzurisin, D.; Lisowski, M.; Schilling, S. P.; Anderson, K. R.; Werner, C. A.

    2015-12-01

    The 2004-2008 dome-building eruption at Mount St. Helens ended during the winter of 2007-2008 at a time when field observations were hampered by persistent bad weather. As a result, recognizing the end of the eruption was challenging. Also challenging was the fact that signs of continued eruption were increasingly subtle — earthquakes were small, deformation signals tiny, gas content close to background — and observing these phenomena was critically dependent on recordings and measurements made close (< 2 km) to the vent. In hindsight, the end of the eruption was presaged by a slight increase in seismicity in December 2007 that culminated on January 12-13, 2008, with a flurry of more than 500 events, most of which occurred in association with several tremor-like signals and a spasmodic burst of long-period earthquakes. At about the same time, a series of regular, localized, small-amplitude tilt events — thousands of which had been recorded during earlier phases of the eruption — came to an end. Thereafter, seismicity declined to 10-20 events per day until January 27-28, when a spasmodic burst of about 50 volcano-tectonic earthquakes occurred over a span of 3 hours. This was followed by a brief return of repetitive "drumbeat" earthquakes that characterized much of the eruption. By January 31, seismicity had declined to 1-2 earthquakes per day, a rate similar to pre-eruption levels. We attribute the tilt and seismic observations to progressive stagnation of an increasingly stiffened plug of magma in the upper part of the conduit. Upward movement of the plug ceased when the excess driving pressure, which had gradually decreased throughout the eruption as a result of reservoir deflation and increasing overburden from the growing dome, was overcome by increasing sidewall friction as a result of cooling and crystallization of the plug.

  1. Plant reestablishment 15 years after the debris avalanche at Mount St Helens, Washington.

    PubMed

    Dale, Virginia H; Adams, Wendy M

    2003-09-01

    Vegetation has slowly reestablished on the debris avalanche deposit in the 15 years after the 1980 eruption of Mount St. Helens that created a 60-km(2) debris avalanche, the largest landslide in recorded history. There has been a gradual increase in species richness and cover, but only 61% of the species present on the mountain before the eruption have established on the debris avalanche deposit. Plant cover averages 38% and is extremely patchy. Life form composition changed over successional time, because part of the avalanche deposit was invaded by introduced plant species aerially seeded to reduce erosion, the site offers the opportunity to compare successional processes occurring with and without introduced species. Long-term recovery trends and effects of nonnative species on succession are important to understand since plant reestablishment practices often rely on nonnative species for enhancing vegetation recovery of denuded sites along road sides, strip mines, or other human-generated clearing. Fifteen years after the eruption and 10 years since the invasion by introduced species, plots invaded by nonnative species had greater vegetation cover and more native plant richness than plots that were not inundated. Significantly greater mortality of conifers occurred in the plots dominated by introduced species shortly after the invasion of those species, but no difference in conifer mortality occurred in the last 5 years. Even so, the plots dominated by introduced species still have fewer conifer trees. Thus, the short-term pulse of conifer mortality after the invasion of introduced species may have long-term effects on the recovery of the dominant vegetation. It will likely be decades before there is 100% plant cover on the debris avalanche deposit and a century or more before full recovery of the vegetation system.

  2. The 2004-2008 dome-building eruption at Mount St. Helens, Washington: epilogue

    NASA Astrophysics Data System (ADS)

    Dzurisin, Daniel; Moran, Seth C.; Lisowski, Michael; Schilling, Steve P.; Anderson, Kyle R.; Werner, Cynthia

    2015-10-01

    The 2004-2008 dome-building eruption at Mount St. Helens ended during winter 2007-2008 at a time when field observations were hampered by persistent bad weather. As a result, recognizing the end of the eruption was challenging—but important for scientists trying to understand how and why long-lived eruptions end and for public officials and land managers responsible for hazards mitigation and access restrictions. In hindsight, the end of the eruption was presaged by a slight increase in seismicity in December 2007 that culminated on January 12-13, 2008, with a burst of more than 500 events, most of which occurred in association with several tremor-like signals and a spasmodic burst of long-period earthquakes. At about the same time, a series of regular, localized, small-amplitude tilt events—thousands of which had been recorded during earlier phases of the eruption—came to an end. Thereafter, seismicity declined to 10-20 events per day until January 27-28, when a spasmodic burst of about 50 volcano-tectonic earthquakes occurred over a span of 3 h. This was followed by a brief return of repetitive "drumbeat" earthquakes that characterized much of the eruption. By January 31, however, seismicity had declined to 1-2 earthquakes per day, a rate similar to pre-eruption levels. We attribute the tilt and seismic observations to convulsive stagnation of a semisolid magma plug in the upper part of the conduit. The upward movement of the plug ceased when the excess driving pressure, which had gradually decreased throughout the eruption as a result of reservoir deflation and increasing overburden from the growing dome, was overcome by increasing friction as a result of cooling and crystallization of the plug.

  3. Inter-Eruption Evolution of Mount St. Helens Tracked by Coda Wave Interferometry

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    Mount St. Helens (MSH) erupted in 2004 after 18 years of quiescence, but the spatio-temporal movement underground of the magma that erupted at the surface remains a mystery. Swarms of deep (3-8 km) seismicity consistent with magmatic recharge beneath MSH occurred in 1989-1991 and 1995-1998, coincident with steam explosions and anomalous CO2 emission, respectively. Ground deformation observed between 1982 and 1991 was similarly consistent with magma recharge. However, there was no measurable ground deformation between 1991 and 2004. This evidence suggests that magma recharge likely took place during the 1989-1991 swarm, or alternatively, that it had already been mostly loaded to further erupt at the end of the 1980-1986 eruption. On other volcanoes, small changes in seismic wavespeed have been observed prior to eruptions and coincident with possible intrusions of fluids. Seismic velocity changes may have also occurred at MSH, and we speculate that the nature of these changes could provide additional constraints on how the system evolved leading up to the 2004 eruption. We compared the waveforms of thousands of pairs of repeating high frequency (>5 Hz) earthquakes in the PNSN catalog that occurred beneath the volcano's summit between the last explosion in 1986 and the onset of eruption in 2004. We measure temporal changes in repeater coda arrivals and interpret them in terms of possible changes in seismic structure and/or source processes using coda wave interferometry. Preliminary results show many pairs of coda waves have linearly increasing or decreasing lag with time within the waveforms, indicative of systematic wavespeed changes. If attributed to shear velocity variations alone, they would need to be as large as 2% spread over several years and change most around the times of increased deep seismicity.

  4. Airborne thermal infrared imaging of the 2004-2005 eruption of Mount St. Helens

    NASA Astrophysics Data System (ADS)

    Schneider, D. J.; Vallance, J. W.; Logan, M.; Wessels, R.; Ramsey, M.

    2005-12-01

    A helicopter-mounted forward-looking infrared imaging radiometer (FLIR) documented the explosive and effusive activity at Mount St. Helens during the 2004-2005 eruption. A gyrostabilzed gimbal controlled by a crew member houses the FLIR radiometer and an optical video camera attached at the lower front of the helicopter. Since October 1, 2004 the system has provided an unprecedented data set of thermal and video dome-growth observations. Flights were conducted as frequently as twice daily during the initial month of the eruption (when changes in the crater and dome occurred rapidly), and have been continued on a tri-weekly basis during the period of sustained dome growth. As with any new technology, the routine use of FLIR images to aid in volcano monitoring has been a learning experience in terms of observation strategy and data interpretation. Some of the unique information that has been derived from these data to date include: 1) Rapid identification of the phreatic nature of the early explosive phase; 2) Observation of faulting and associated heat flow during times of large scale deformation; 3) Venting of hot gas through a short lived crater lake, indicative of a shallow magma source; 4) Increased heat flow of the crater floor prior to the initial dome extrusion; 5) Confirmation of new magma reaching the surface; 6) Identification of the source of active lava extrusion, dome collapse, and block and ash flows. Temperatures vary from ambient, in areas insulated by fault gouge and talus produced during extrusion, to as high as 500-740 degrees C in regions of active extrusion, collapse, and fracturing. This temperature variation needs to be accounted for in the retrieval of eruption parameters using satellite-based techniques as such features are sub-pixel size in satellite images.

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

    USGS Publications Warehouse

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

    2008-01-01

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

  6. Effects of lava-dome growth on the crater glacier of Mount St. Helens, Washington: Chapter 13 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Walder, Joseph S.; Schilling, Steve P.; Vallance, James W.; LaHusen, Richard G.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    The process of lava-dome emplacement through a glacier was observed for the first time as the 2004-6 eruption of Mount St. Helens proceeded. The glacier that had grown in the crater since the cataclysmic 1980 eruption was split in two by the new lava dome. The two parts of the glacier were successively squeezed against the crater wall. Photography, photogrammetry, and geodetic measurements document glacier deformation of an extreme variety, with strain rates of extraordinary magnitude as compared to normal temperate alpine glaciers. Unlike such glaciers, the Mount St. Helens crater glacier shows no evidence of either speed-up at the beginning of the ablation season or diurnal speed fluctuations during the ablation season. Thus there is evidently no slip of the glacier over its bed. The most reasonable explanation for this anomaly is that meltwater penetrating the glacier is captured by a thick layer of coarse rubble at the bed and then enters the volcano’s groundwater system rather than flowing through a drainage network along the bed. Mechanical consideration of the glacier-squeeze process also leads to an estimate for the driving pressure applied by the growing lava dome.

  7. Mount St Helens eruptions, May 18 to June 12, 1980. An overview of the acute health impact.

    PubMed

    Baxter, P J; Ing, R; Falk, H; French, J; Stein, G F; Bernstein, R S; Merchant, J A; Allard, J

    1981-12-04

    Thirty-five known deaths were caused by the landslide and lateral blast of the May 18 eruption of Mount St Helens and at least 23 persons are missing. In 18 of 23 cases that reached autopsy, asphyxiation from ash inhalation was the cause of death. A rapidly established hospital surveillance system detected increases in the number of emergency room (ER) visits and admissions for asthma and bronchitis in communities with the heaviest ashfall after the May 18 eruption and the eruptions on May 25 and June 12. There were also increases in the number of ER visits for ash-related eye complaints in some areas. laboratory studies indicated that the May 18 ash was not acutely toxic, but the respirable portion contained 3% to 7% of crystalline free silica, a potential pneumoconiosis hazard to certain heavily exposed occupational groups. Continuing volcanic activity of Mount St Helens and future eruption of other volcanoes in the Cascade Range may pose a variety of health hazards, including blast, ashfalls, flooding, damage to public utilities, and possible psychosocial effects.

  8. Ambient Airborne Solids Concentrations Including Volcanic Ash at Hanford, Washington Sampling Sites Subsequent to the Mount St. Helens Eruption

    SciTech Connect

    Sehmel, G.A.

    1982-12-20

    A major eruption of Mount St. Helens occurred on May 18, 1980. Subsequently, airborne solid concentrations were measured as a function of time at two sites within the southern edge of the fallout plume about 211 km east of Mount St. Helens. This ash was a source for investigating area-wide resuspension. Rain had a variable effect on decreasing airborne concentrations from resuspension. From 0.5 to 1.5 cm of rain were required to significantly reduce airborne solid concentrations through July. For a more aged resuspension source in September, a rain of 2.0 cm had a negligible effect. A monthly average threshold-wind speed for resuspension was defined as 3.6 m/s. For monthly-average wind speeds less than the threshold wind speed, monthly-average airborne concentrations tended to decrease with time. A decrease was recorded between September and October. For this 4-month time period, the half-life was on the order of 50 days, corresponding to a weathering rate of 5.1 year/sup -1/.

  9. Evaluation of physical health effects due to volcanic hazards: crystalline silica in Mount St. Helens volcanic ash.

    PubMed

    Dollberg, D D; Bolyard, M L; Smith, D L

    1986-03-01

    This investigation has shown that crystalline silica has been identified as being present in the Mount St. Helens volcanic ash at levels of 3 to 7 per cent by weight. This identification has been established using X-ray powder diffraction, infrared spectrophotometry, visible spectrophotometry, electron microscopy, and Laser Raman spectrophotometry. Quantitative analysis by IR, XRD, and visible spectrophotometry requires a preliminary phosphoric acid digestion of the ash sample to remove the plagioclase silicate material which interferes with the determination by these methods. Electron microscopic analysis as well as Laser Raman spectrophotometric analysis of the untreated ash confirms the presence of silica and at levels found by the XRD and IR analysis of the treated samples. An interlaboratory study of volcanic ash samples by 15 laboratories confirms the presence and levels of crystalline silica. Although several problems with applying the digestion procedure were observed in this hastily organized supply, all laboratories employing the digestion procedure reported the presence of crystalline silica. These results unequivocally put to rest the question of the presence of silica in the volcanic ash from eruptions of Mount St. Helens in 1980.

  10. The mechanics of ground deformation precursory to dome-building extrusions at Mount St. Helens 1981-1982.

    USGS Publications Warehouse

    Chadwick, W.W.; Archuleta, R.J.; Swanson, D.A.

    1988-01-01

    Detailed monitoring at Mount St. Helens since 1980 has enabled prediction of the intermittent eruptive activity (mostly dome growth) with unprecedented success. During 1981 and 1982, accelerating deformation of the crater floor around the vent (including radial cracks, thrust faults, and ground tilt) was the earliest indicator of impending activity. The magnitude of the shear stress required to match observed dipslacements (1-7 MPa) is inversely proportional to the conduit diameter (estimated to be 25-100 m). The most probable source of this shear stress is the flow of viscous magma up to the conduit and into the lava dome. A model is proposed in which the accelerating deformation, beginning as much as 4 weeks before extrusions, is caused by the increasing velocity of ascending magma in the conduit. This model is examined by using deformation data of the dome before four extrusions in 1981 and 1982 to estimate the volumetric flow rate through the conduit. This flow rate and an estimate of the effective viscosity of the magma enable calculation of an ascent velocity and an applied shear stress that, again, depend on the conduit diameter. The results of these calculations are consistent with the finite element experiments and show that the proposed model is feasible. Precursory deformation like that measured at Mount St. Helens should be observable at similar volcanoes elsewhere because it is caused by the fundamental process of magma ascent.-from Authors

  11. Evaluation of physical health effects due to volcanic hazards: crystalline silica in Mount St. Helens volcanic ash

    SciTech Connect

    Dollberg, D.D.; Balyard, M.L.; Smith, D.L.

    1986-03-01

    This investigation has shown that crystalline silica has been identified as being present in the Mount St. Helens volcanic ash at levels of 3 to 7 per cent by weight. This identification has been established using X-ray powder diffraction, infrared spectrophotometry, visible spectrophotometry, electron microscopy, and Laser Raman spectrophometry. Quantitative analysis by IR, XRD, and visible spectrophotometry requires a preliminary phosphoric acid digestion of the ash sample to remove the plagioclase silicate material which interferes with the determination by these methods. Electron microscopic analysis as well as Laser Raman spectrophotometric analysis of the untreated ash confirms the presence of silica and at levels found by the XRD and IR analysis of the treated samples. An interlaboratory study of volcanic ash samples by 15 laboratories confirms the presence and levels of crystalline silica. Although several problems with applying the digestion procedure were observed in this hastily organized study, all laboratories employed the digestion procedure reported the presence of crystalline silica. These results unequivocally put to rest the question of the presence of silica in the volcanic ash from eruptions of Mount St. Helens in 1980.

  12. Commentary on: "On the Need for a Specialist Service within the Generic Hospital Setting" by Robyn A. Wallace and Helen Beange (2008)

    ERIC Educational Resources Information Center

    Kerr, Michael

    2008-01-01

    This commentary discusses whether a sufficient case has been made for specialism in hospital services as a viable alternative to existing generic services. The impact of developments in specialist care such as those outlined by Robyn A. Wallace and Helen Beange should be assessed as a means of reducing inequality. In particular, model services…

  13. An Overview of the Project on the Imaging and Full-Text Retrieval of the Ava Helen and Linus Pauling Papers at the Oregon State University Libraries.

    ERIC Educational Resources Information Center

    Krishnamurthy, Ramesh S.; Mead, Clifford S.

    1995-01-01

    Presents plan of Oregon State University Libraries to convert all paper documents from the Ava Helen and Linus Pauling archives to digital format. The scope, goals, tasks and objectives set by the project coordinators are outlined, and issues such as protection of equipment, access, copyright and management are discussed. (JKP)

  14. Commentary on: "On the Need for a Specialist Service within the Generic Hospital Setting" by Robyn A. Wallace and Helen Beange (2008)

    ERIC Educational Resources Information Center

    Kerr, Michael

    2008-01-01

    This commentary discusses whether a sufficient case has been made for specialism in hospital services as a viable alternative to existing generic services. The impact of developments in specialist care such as those outlined by Robyn A. Wallace and Helen Beange should be assessed as a means of reducing inequality. In particular, model services…

  15. Little Black Sambo: A Closer Look. A History of Helen Bannerman's The Story of Little Black Sambo and its Popularity/Controversy in the United States.

    ERIC Educational Resources Information Center

    Yuill, Phyllis J.

    Surprisingly little research has been done on Little Black Sambo and the meager material is often contradictory. This study examines the origins of the book and traces its history in the United States through its overlapping periods of popularity and controversy. The story of Little Black Sambo, written in 1898 by Helen Bannerman, a white English…

  16. Plagioclase in Dacites of the Current Mt. St. Helens Eruption: Constraints for Magma Origin and Dynamics

    NASA Astrophysics Data System (ADS)

    Streck, M. J.; Broderick, C.; Thornber, C. R.; Clynne, M. A.; Pallister, J. S.

    2005-12-01

    The current, now year-long eruption of Mt. St. Helens is remarkable for a variety of reasons. Nearly solid, gas-poor dacite lava is extruding at the surface. Earthquakes are limited to the upper 3 km with most occurring less than 1 km below the surface; no deeper seismicity has been observed. Emissions of SO2, H2S, CO2 are extremely low, suggesting eruption of degassed magma. No direct evidence for mingling of more mafic magma has been observed. We investigated plagioclase crystals in 2004-5 dacite and 1980-86 dacite dome rocks to shed light on the nature and origin of the current magma. Polarized light and Nomarski microscopy in combination with detailed microprobe traverses were used to characterize single plagioclase crystals, focusing on areas near their rims. In addition, we mapped all plagioclase crystals within an area of ~1/3 of each thin section and grouped them according to easily distinguishable mineral features. Although labor-intensive, this new approach was devised to generate data statistically significant enough to compare plagioclase crystal populations of crystal-rich samples. Mappable features within crystals include: i) zones of acicular opx microlitic inclusions (commonly occurring near the rim), ii) resorption surfaces, iii) spatial association of i) and ii). Our key results from the crystal mapping indicate that sequential samples of 2004/5 have remained comparable, but are distinct from 1980-86 dacite dome samples. We interpret this result as strong evidence that the 2004-5 dacite is new magma and not 'left-over' 1980's dacite. The most interesting result from combining compositional profiling with texture is that acicular opx inclusions occur at the lowest observed An content of 40-33 regardless of position within crystal and that overgrowth on resorption surfaces are typically 10-20 mol% higher in An than within opx-rich zones resulting in single to multiple oscillations of An content towards the rim. These features could possibly be

  17. Evaluation of gas data from high-temperature fumaroles at Mount St. Helens, 1980-1982

    USGS Publications Warehouse

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

    1986-01-01

    The Mount St. Helens fumarole gases show linear composition trends during periods of noneruptive degassing between September 1980 and October 1981. The trends are characterized by increasing H2O and decreasing CO2 and sulfur. Maximum fumarole temperatures also show a linear decrease during this period. High-temperature fumarole gases collected from the crater and dome between September 1980 and July 1982 are all H2O-rich (> 90%) with 1-10% CO2 and small amounts of H2S, SO2, H2, CO, HC, and HF. Trace amounts of COS and S2 are present, and occasional observations of minor CH4 appear to result from contamination or low-temperature reactions in sample vessels. The O2 fugacities of the gases remain near Ni-NiO during cooling. The low sulfur content of the gases obviates the need for extensive gas-rock oxygen exchange to maintain fO2's near Ni-NiO. A detailed thermodynamic analysis of 50 gas samples collected between September 1980 and December 1981 led to improved compositions for 22 samples. The gases were initially in a state of equilibrium, but disequilibrium modifications from atmospheric oxidation of H2 and, to a lesser extent, CO occurred within the upper portions of the fumarole vents. The last temperatures of equilibrium for the fumarole gases range from 800??C to 650??C and are nearly always higher than the collection temperatures. No evidence was found of disequilibrium admixture of surface waters; if such modifications of the fumarole gases occurred, the water must have been added at depth and have reequilibrated with the other gas species at magmatic or near-magmatic temperatures. The highest quality analytical data are obtained by field gas chromatograph measurements and from caustic soda bottle samples. Samples collected in evacuated bottles or by pumping through double stopcock tubes tend to be severely deficient in sulfur due to post-collection reactions between H2S and SO2. It is also necessary to infer the water content of the latter samples. ?? 1986.

  18. Integrating field and numerical techniques to understand the dynamics of pyroclastic density currents: Mount St Helens

    NASA Astrophysics Data System (ADS)

    Brand, B. D.; Dufek, J.; Mackaman-lofland, C. A.; Pollock, N.

    2011-12-01

    The 9 hour, May 18th, 1980 eruption of Mount St Helens (MSH) is one of the best studied explosive volcanic eruptions within the past 100 years. Observations of plume height, combined with subsequent studies of ash dispersal, provide key constraints to the temporally varying mass flux from throughout the day on May 18th (Carey, S., Sigurdsson, H., Gardner, J.E., Criswell, W. J Volcanol Geotherm Res, 43: 99-112). An increase in eruptive intensity through the afternoon resulted in the generation of many pyroclastic density currents (PDCs), which filled in the pumice plain just north of the volcano. Deeply incised drainages provide new, extensive exposures that contain important information about the currents that produced them. Numerical models provide a framework to integrate field observations such as particle size, sorting, rounding and maximum lithic size versus distance from the vent, improving the general understanding of transport and deposition in PDCs. Thus visual observations and estimates of mass flux, detailed measurements of recently exposed strata, and multiphase numerical modeling are being combined to better constrain the dynamics of the PDCs produced on May 18th. Five flow units have been identified along the large western drainage of the pumice plain, each of which have intricate vertical and lateral facies changes and complex cross-cutting relationships away from source. Field relationships and the presence of pre-existing obstacles are used to back out flow direction and gain insight into PDC emplacement mechanisms. A few of the currents produced during the afternoon of May 18 were energetic enough to entrain dense lithic clasts, 10's of centimeters in diameter, and transport them 10's of meters downstream. Deposit features in these areas show a concentration of blocks at the base of flow units and evidence for self-channelization, suggesting the increased bulk density of the current and channelization resulted in an enhanced vertical density

  19. The source of infrasound associated with long-period events at mount St. Helens

    USGS Publications Warehouse

    Matoza, R.S.; Garces, M.A.; Chouet, B.A.; D'Auria, L.; Hedlin, M.A.H.; De Groot-Hedlin, C.; Waite, G.P.

    2009-01-01

    During the early stages of the 2004-2008 Mount St. Helens eruption, the source process that produced a sustained sequence of repetitive long-period (LP) seismic events also produced impulsive broadband infrasonic signals in the atmosphere. To assess whether the signals could be generated simply by seismic-acoustic coupling from the shallow LP events, we perform finite difference simulation of the seismo-acoustic wavefield using a single numerical scheme for the elastic ground and atmosphere. The effects of topography, velocity structure, wind, and source configuration are considered. The simulations show that a shallow source buried in a homogeneous elastic solid produces a complex wave train in the atmosphere consisting of P/SV and Rayleigh wave energy converted locally along the propagation path, and acoustic energy originating from , the source epicenter. Although the horizontal acoustic velocity of the latter is consistent with our data, the modeled amplitude ratios of pressure to vertical seismic velocity are too low in comparison with observations, and the characteristic differences in seismic and acoustic waveforms and spectra cannot be reproduced from a common point source. The observations therefore require a more complex source process in which the infrasonic signals are a record of only the broadband pressure excitation mechanism of the seismic LP events. The observations and numerical results can be explained by a model involving the repeated rapid pressure loss from a hydrothermal crack by venting into a shallow layer of loosely consolidated, highly permeable material. Heating by magmatic activity causes pressure to rise, periodically reaching the pressure threshold for rupture of the "valve" sealing the crack. Sudden opening of the valve generates the broadband infrasonic signal and simultaneously triggers the collapse of the crack, initiating resonance of the remaining fluid. Subtle waveform and amplitude variability of the infrasonic signals as

  20. Spatial analysis of Mount St. Helens tephra leachate compositions: implications for future sampling strategies.

    PubMed

    Ayris, P M; Delmelle, P; Pereira, B; Maters, E C; Damby, D E; Durant, A J; Dingwell, D B

    Tephra particles in physically and chemically evolving volcanic plumes and clouds carry soluble sulphate and halide salts to the Earth's surface, ultimately depositing volcanogenic compounds into terrestrial or aquatic environments. Upon leaching of tephra in water, these salts dissolve rapidly. Previous studies have investigated the spatial and temporal variability of tephra leachate compositions during an eruption in order to gain insight into the mechanisms of gas-tephra interaction which emplace those salts. However, the leachate datasets analysed are typically small and may poorly represent the natural variability and complexity of tephra deposits. Here, we have conducted a retrospective analysis of published leachate analyses from the 18 May 1980 eruption of Mount St. Helens, Washington, analysing the spatial structure of the concentrations and relative abundances of soluble Ca, Cl, Na and S across the deposits. We have identified two spatial features: (1) concentrated tephra leachate compositions in blast deposits to the north of the volcano and (2) low S/Cl and Na/Cl ratios around the Washington-Idaho border. By reference to the bulk chemistry and granulometry of the deposit and to current knowledge of gas-tephra interactions, we suggest that the proximal enrichments are the product of pre-eruptive gas uptake during cryptodome emplacement. We speculate that the low S/Cl and Na/Cl ratios reflect a combination of compositional dependences on high-temperature SO2 uptake and preferential HCl uptake by hydrometeor-tephra aggregates, manifested in terrestrial deposits by tephra sedimentation and fallout patterns. However, despite our interrogation of the most exhaustive tephra leachate dataset available, it has become clear in this effort that more detailed insights into gas-tephra interaction mechanisms are prevented by the prevalent poor temporal and spatial representativeness of the collated data and the limited characterisation of the tephra deposits. Future

  1. Spatial analysis of Mount St. Helens tephra leachate compositions: implications for future sampling strategies

    NASA Astrophysics Data System (ADS)

    Ayris, P. M.; Delmelle, P.; Pereira, B.; Maters, E. C.; Damby, D. E.; Durant, A. J.; Dingwell, D. B.

    2015-07-01

    Tephra particles in physically and chemically evolving volcanic plumes and clouds carry soluble sulphate and halide salts to the Earth's surface, ultimately depositing volcanogenic compounds into terrestrial or aquatic environments. Upon leaching of tephra in water, these salts dissolve rapidly. Previous studies have investigated the spatial and temporal variability of tephra leachate compositions during an eruption in order to gain insight into the mechanisms of gas-tephra interaction which emplace those salts. However, the leachate datasets analysed are typically small and may poorly represent the natural variability and complexity of tephra deposits. Here, we have conducted a retrospective analysis of published leachate analyses from the 18 May 1980 eruption of Mount St. Helens, Washington, analysing the spatial structure of the concentrations and relative abundances of soluble Ca, Cl, Na and S across the deposits. We have identified two spatial features: (1) concentrated tephra leachate compositions in blast deposits to the north of the volcano and (2) low S/Cl and Na/Cl ratios around the Washington-Idaho border. By reference to the bulk chemistry and granulometry of the deposit and to current knowledge of gas-tephra interactions, we suggest that the proximal enrichments are the product of pre-eruptive gas uptake during cryptodome emplacement. We speculate that the low S/Cl and Na/Cl ratios reflect a combination of compositional dependences on high-temperature SO2 uptake and preferential HCl uptake by hydrometeor-tephra aggregates, manifested in terrestrial deposits by tephra sedimentation and fallout patterns. However, despite our interrogation of the most exhaustive tephra leachate dataset available, it has become clear in this effort that more detailed insights into gas-tephra interaction mechanisms are prevented by the prevalent poor temporal and spatial representativeness of the collated data and the limited characterisation of the tephra deposits. Future

  2. Investigation into the erosive capacity of pyroclastic density currents at Mount Saint Helens, Washington (USA)

    NASA Astrophysics Data System (ADS)

    Pollock, N. M.; Brand, B. D.

    2012-12-01

    Two fundamental aspects of PDC dynamics that remain poorly understood are the primary control(s) on substrate erosion and the effect of erosion on downstream flow dynamics. The gap in understanding reflects the lack of sufficient field exposures with evidence for these processes. In the 32 years since the May 18th, 1980 eruption of Mount St Helens (MSH), kilometers of new outcrops have been exposed throughout the PDC and debris avalanche hummock deposits that provide substantial evidence of substrate erosion and entrainment by the PDCs produced throughout the afternoon of the eruption. Field observations include a reappearance of large lithics (>1 m) in PDC deposits at distances of 4-5 km from the vent, suggesting that these lithics were entrained locally. For this study, detailed componentry and roundness analyses are utilized to determine the source of lithics in PDC deposits and to quantify the erosive capacity of the PDCs at MSH. Comparison of componentry data from the PDC deposits with debris avalanche deposits ~200 m upstream indicate that >50% of the lithics were locally entrained. The entrainment of these lithics appears to have significantly altered the dynamics of the current as contacts between flow units change from purely depositional upstream from the hummocks to erosive and scouring following the entrainment of dense lithics. This evidence suggests that the capacity of a PDC to behave erosively could be a self-perpetuating process; entrainment of dense lithics at the base of the current results in an increased density gradient, which in turn enhances a current's ability to continue to erode. In addition, the presence of locally entrained lithics at various heights within a single flow unit and within close proximity to the source of the lithics suggests both a progressive entrainment of the substrate as well as a progressive aggradation of the deposits, depending on localized flow conditions. While erosion may have initially occurred due to the

  3. Modelling spatiotemporal change using multidimensional arrays Meng

    NASA Astrophysics Data System (ADS)

    Lu, Meng; Appel, Marius; Pebesma, Edzer

    2017-04-01

    The large variety of remote sensors, model simulations, and in-situ records provide great opportunities to model environmental change. The massive amount of high-dimensional data calls for methods to integrate data from various sources and to analyse spatiotemporal and thematic information jointly. An array is a collection of elements ordered and indexed in arbitrary dimensions, which naturally represent spatiotemporal phenomena that are identified by their geographic locations and recording time. In addition, array regridding (e.g., resampling, down-/up-scaling), dimension reduction, and spatiotemporal statistical algorithms are readily applicable to arrays. However, the role of arrays in big geoscientific data analysis has not been systematically studied: How can arrays discretise continuous spatiotemporal phenomena? How can arrays facilitate the extraction of multidimensional information? How can arrays provide a clean, scalable and reproducible change modelling process that is communicable between mathematicians, computer scientist, Earth system scientist and stakeholders? This study emphasises on detecting spatiotemporal change using satellite image time series. Current change detection methods using satellite image time series commonly analyse data in separate steps: 1) forming a vegetation index, 2) conducting time series analysis on each pixel, and 3) post-processing and mapping time series analysis results, which does not consider spatiotemporal correlations and ignores much of the spectral information. Multidimensional information can be better extracted by jointly considering spatial, spectral, and temporal information. To approach this goal, we use principal component analysis to extract multispectral information and spatial autoregressive models to account for spatial correlation in residual based time series structural change modelling. We also discuss the potential of multivariate non-parametric time series structural change methods, hierarchical modelling, and extreme event detection methods to model spatiotemporal change. We show how array operations can facilitate expressing these methods, and how the open-source array data management and analytics software SciDB and R can be used to scale the process and make it easily reproducible.

  4. Isotopic Insights Into the Degassing and Secondary Hydration Rates of Volcanic Glass From the 1980 Eruptions of Mount St. Helens

    NASA Astrophysics Data System (ADS)

    Seligman, A. N.; Bindeman, I. N.; Van Eaton, A. R.; Hoblitt, R. P.

    2016-12-01

    Following eruption, volcanic glass undergoes hydration in its depositional environment, which overprints the history of magmatic degassing recorded in the glass. However, the rates of secondary hydration of volcanic glass used for paleoclimate studies are poorly constrained. Here, we present our results of a natural experiment using products of the 1980 eruptions of Mount St. Helens. We measured the δD of extracted water and the δ18O of the bulk glass of samples collected during the dry summer months of 1980 and compared them with material resampled in August of 2015. Results demonstrate that only samples collected from the subsurface near gas escape pipes show elevated water concentrationss (near 2.0 wt.%) and low δD (-110 to -130 ‰) and δ18O (6.0 to 6.6 ‰) values, and that the initial process of secondary hydration is not always a simple addition of low δD waters at ambient temperature. On average, the 2015 surface samples have slightly higher water contents (0.1-0.2 wt.%) and similar δ18O (6.8 - 6.9 ‰) to those collected in 1980. Given the moderate vesicularity of the samples and the slow rate of surface temperature diffusion, we attribute these observations to hydration during cooling, with only little exchange after. We also compare our results to rapidly quenched air fall pumice from the May 18th eruption, which shows moderate δD values (-74 ‰) and water concentrations (0.3 wt.%) that are closer to those for the 1980 samples. Surprisingly, the 2015 surface samples show higher δD values (+15 ‰), which we attribute to any of four possibilities: (1) evaporation or (2) degassing of underlying deposits; (3) exchange of hydrogen with local vegetation; and/or (4) microlite crystallization that aided diffusion of water. Reconstructed δD-H2O trends for the Mount St. Helens samples collected in 1980 support previous studies proposing that exsolved volatiles were trapped within a rapidly rising magma that degassed at shallow depths. The dacitic Mount

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

    USGS Publications Warehouse

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

    1986-01-01

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

  6. Separating long-term deformation cycles and atmospheric signals at Mount St. Helens using PS-InSAR

    NASA Astrophysics Data System (ADS)

    Welch, M.

    2015-12-01

    Since its eruption in 1980, Mount St. Helens has experienced multiple inflation-deflation cycles associated with dome building eruptions. During the most recent dome-building episode, which spanned 2004 to 2008, GPS recorded the transition from pre-eruptive inflation to co-eruptive deflation and a final transition back to inflation. Such observations provide important constraints on the timing and mechanics of cyclic magma recharge and extrusion. Currently, the subtle surface deformation signal at St Helens is monitored primarily by ground based geodetic techniques like GPS. Satellite-based InSAR has the potential to substantially augment these techniques by providing spatially continuous, precise measurements of surface displacements, and may also reveal other volcanic or surficial processes too localized to be detected by ground based methods. Traditional interferometry is challenging to apply to volcanoes in the Cascades. Widespread phase decorrelation caused by persistent snow cover and dense vegetation, combined with large, elevation dependent atmospheric phase delays, mask or make deformation signals difficult to detect. By applying StaMPS, a Persistent Scatterers (PS) technique, phase decorrelation is mitigated by utilizing only the pixels with the highest, statistically derived, signal to noise ratio. However, atmospheric water vapor, which delays the radar signal, remains problematic, particularly on the volcano edifice. To assess the bias imposed by the atmosphere, we perform a series of sensitivity tests using a suite of methods including several that rely on the linear or power-law correlation of phase delay to topography and knowledge of the spatial scale of the signal. We also apply methods that calculate wet and dry phase delay from atmospheric reanalysis datasets such as ERA-Interim provided by the ECMWF. SAR data from the ERS, Envisat, and ALOS satellites, along with newer datasets, are processed with these tools to create a time series spanning

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

    NASA Astrophysics Data System (ADS)

    Gerlach, Terrence M.; Casadevall, Thomas J.

    1986-05-01

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

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

    USGS Publications Warehouse

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

    2008-01-01

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

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

    USGS Publications Warehouse

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

    2008-01-01

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

  10. Extrusion rate of the Mount St. Helens lava dome estimated from terrestrial imagery, November 2004-December 2005: Chapter 12 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Major, Jon J.; Kingsbury, Cole G.; Poland, Michael P.; LaHusen, Richard G.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    Oblique, terrestrial imagery from a single, fixed-position camera was used to estimate linear extrusion rates during sustained exogenous growth of the Mount St. Helens lava dome from November 2004 through December 2005. During that 14-month period, extrusion rates declined logarithmically from about 8-10 m/d to about 2 m/d. The overall ebbing of effusive output was punctuated, however, by episodes of fluctuating extrusion rates that varied on scales of days to weeks. The overall decline of effusive output and finer scale rate fluctuations correlated approximately with trends in seismicity and deformation. Those correlations portray an extrusion that underwent episodic, broad-scale stick-slip behavior superposed on the finer scale, smaller magnitude stick-slip behavior that has been hypothesized by other researchers to correlate with repetitive, nearly periodic shallow earthquakes.

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

    USGS Publications Warehouse

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

    2008-01-01

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

  12. Mass Intrusion at Mount St. Helens (WA) Between 2010 and 2014 from Temporal Gravity Variations Mass Intrusion at Mount St. Helens (WA) Between 2010 and 2014 from Temporal Gravity Variations

    NASA Astrophysics Data System (ADS)

    Battaglia, M.; Lisowski, M.; Dzurisin, D.; Poland, M. P.

    2014-12-01

    Repeated high-precision gravity measurements made at Mount St. Helens (WA) have revealed systematic temporal variations in the gravity field several years after the 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 in the summit region and at 4 sites far afield (10 to 36 km) from the summit in August 2010 and August 2012. After removing the gravity signal associated with changes in mass of the crater glacier and the local (perched) hydrothermal aquifer, the gravity field observed at sites near the volcano's summit significantly increased with respect to sites far from the summit (maximum change 146 ±7 μgal). The pattern of gravity increase is radially symmetrical, with a half-width around 3 km and a point of maximum change centered 1.5 km NW of the 2004-2008 lava dome. Inversion of residual gravity data using the same source geometry, depth and location inferred from geodetic data (a spheroidal source centered 7.5 km beneath the 2004-2008 dome) indicates a mass increase of about 1012 kg. For a reasonable magma density (~2250 kg/m3), the volume of magma intrusion beneath the summit region inferred from gravity exceeds the volume inferred from inversion of geodetic data, suggesting that magma compressibility and other processes are important aspects of magma storage at Mount St. Helens. A third survey will be completed in August 2014, and we will present results of those measurements in the context of the 2010-2012 gravity changes.

  13. Explosive tephra emissions of Mount St. Helens, 1989-1991: the violent escape of magmatic gas following storms?

    USGS Publications Warehouse

    Mastin, L.G.

    1994-01-01

    From 24 August 1989 until 18 June 1991, Mount St. Helens produced at least 28 shallow, explosion-like seismic events with signatures similar to those produced by gas explosions on the dome during the mid 1980s. At least six were accompanied by violent emission of non-juvenile tephra, ejection of blocks of rock nearly 1 km from the vent, and avalanching of debris off the north side of the dome. All six confirmed emissions and most (although not all) other seismic events took place hours to days after storms. The short delay between storms and emissions suggests that the events that follow storms originate at very shallow depth, probably within the dome itself. Although the exact causal mechanism is not known, it is speculated that slope instability or accelerated growth of cooling fractures following storms may have released gas trapped within or at the base of the dome. -from Author

  14. Chemistry of thermal waters and mineralogy of the new deposits at Mount St. Helens: a preliminary report

    SciTech Connect

    Dethier, D.P.; Frank, D.; Peavear, D.R.

    1980-12-01

    After May 18, 1980 eruption of Mount St. Helens, Washington, interactions between the hot deposits and shallow ground water produced ephemeral phreatic eruptions and thermal ponds and streams. In early June water and sediment samples were collected from about 20 sites in the devastated zone to study the initial alteration of the new deposits, and the effects of the eruption on water chemistry. The levels of certain trace elements in thermal waters, and whether these mineralized waters were reaching the North Fork Toutle River in appreciable quantities were studied. Collection and analysis procedures, the mineralogy of the new deposits, and the chemistry of the thermal waters are discussed. Finally, the chemistry of water from different deposits is compared, alteration reactions suggested by the water chemistry, and the mineralogy of the deposits is discussed.

  15. Rates and processes of channel development and recovery following the 1980 eruption of Mount St. Helens, Washington

    USGS Publications Warehouse

    Meyer, D.F.; Martinson, H.A.

    1989-01-01

    Stream channel development in response to the eruption of Mount St. Helens on 18 May 1980, resulted in some of the largest sediment yields documented anywhere on earth. Development of new channels on the 2.7 km3 debris-avalanche deposit in the North Fork Toutle River caused net erosion of as much as 1.3 X 105 t km-2 annually. The principal effect of the blast on channels throughout the 550 km2 devastated area was the subsequent rapid delivery of sand- and silt-size sediment eroded from hillslopes. Since 1984, instability and sedimentation in lahar and blast-affected channels have been within the range of pre-1980 levels. -from Authors

  16. The mount st. Helens volcanic eruption of 18 may 1980: large short-term surface temperature effects.

    PubMed

    Robock, A; Mass, C

    1982-05-07

    The surface temperature effects of the 18 May 1980 eruption of Mount St. Helens Volcano were examinedfor 1 day immediately after the eruption; 24-hour temperature differences and Model Output Statistics errors as well as the detailed temporal evolution of surface temperature at selected stations were used. During the daytime hours immediately after the eruption, the temperature was suppressed by the volcanic plume by as much as 8 degrees C. That night, low-level volcanic dust produced temperature enhancements of up to 8 degrees C. These effects quickly diminished the next day as the volcanic dust cloud dissipated and moved toward the east. The net local effect of the eruption appears to be warming, in contrast to cooling which might be expected over climatic time scales.

  17. Growth of cells in culture treated with the soluble component of volcanic ash from Mount St. Helens.

    PubMed

    Hosick, H L; Carrington, C A; Angello, J C; Zamora, P O

    1982-12-01

    Volcanic ash was collected immediately after the eruption of Mount St. Helens on May 18, 1980. This ash was extracted with water. The elemental composition of the extracted portion was determined by atomic absorption spectrometry. The aqueous extract was applied at high concentrations (up to 37.5 micrograms/ml) to non-confluent mixed cultures of mouse lung cells. Even after treatment for up to 10 days, cell number was typically unaffected by the ash extract. Cell viability was also unaltered, and no grossly observable changes were noted in the cells by light microscopy. We conclude that the water-soluble portion of the ash we tested does not markedly affect growth of the cells most at risk, those of the lung.

  18. Automated detection and location of microseismicity at Mount St. Helens with a large-N geophone array

    NASA Astrophysics Data System (ADS)

    Hansen, Steven M.; Schmandt, Brandon

    2015-09-01

    In the summer of 2014 a dense array of 904 geophones was deployed at Mount St. Helens along the road and trail system within 15 km distance of the summit crater. The array recorded continuous data for approximately 2 weeks and presents an unprecedented seismic observation of an active volcano. A reverse-time imaging method is applied to short-term-average over long-term-average time series data to automatically detect and locate microseismicity. These efforts resulted in an order of magnitude increase in earthquake detections over the normal monitoring operations of the Pacific Northwest Seismic Network. Earthquake locations resolve a narrow, ≤1 km wide, vertical lineament of seismicity which extends from the surface to 4 km depth directly beneath the summit crater. This feature is interpreted as a fracture network that acts as a conduit connecting an underlying magma chamber to the surface.

  19. Fluoride distribution and biological availability in the fallout from mount st. Helens, 18 to 21 may 1980.

    PubMed

    Taves, D R

    1980-12-19

    Concentrations of fluoride in the ash fallout in central Washington from the 18 May 1980 eruption of Mount St. Helens varied severalfold, but none are high enough to constitute any immediate hazard to animal life. The heaviest fallout (Moses Lake) contained 113 parts per million (ppm) of acid-labile fluoride, but of this only 11 ppm was water-soluble and 20 ppm was available to rats. The fluoride concentrations in the urine of cattle feeding for 4 days on hay contaminated with this ash were essentially normal. Samples of ash from other areas generally had higher concentrations of acid-labile fluoride but lower concentrations of water-soluble fluoride. The concentration of water-soluble fluoride was inversely correlated with the coarseness of the fallout.

  20. Development of a multidisciplinary plan for evaluation of the long-term health effects of the Mount St. Helens eruptions

    SciTech Connect

    Buist, A.S.; Martin, T.R.; Shore, J.H.; Butler, J.; Lybarger, J.A.

    1986-03-01

    The emphasis of this article is on the approach that was taken to evaluating the chronic or delayed effects of the volcanic eruptions of Mount St. Helens in 1980. This strategy has been very successful and may be useful as a model for addressing the possible health effects of other environmental hazards. The steps in this process were: 1) identification of the physical and physicochemical characteristics of the hazard; 2) formation of hypotheses about biologically plausible effects of the hazard on human health; and 3) development of a plan for evaluating the health effects and, were possible, for controlling or minimizing adverse health effects. The third step involved a multidisciplinary group that included public health officials, medical specialists, and research scientists, including a geologist.