William E Scott
In retirement I am working on completing a geologic map of Mount Hood volcano, Oregon.
Science and Products
Filter Total Items: 70
Extrusion rate of the Mount St. Helens lava dome estimated from terrestrial imagery, November 2004-December 2005 Extrusion rate of the Mount St. Helens lava dome estimated from terrestrial imagery, November 2004-December 2005
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...
Authors
Jon J. Major, Cole G. Kingsbury, Michael P. Poland, Richard G. LaHusen
Trace element and Pb isotope composition of plagioclase from dome samples from the 2004-2005 eruption of Mount St. Helens, Washington Trace element and Pb isotope composition of plagioclase from dome samples from the 2004-2005 eruption of Mount St. Helens, Washington
We report the results of in-situ laser ablation ICP–MS analyses of anorthite content, trace-element (Li, Ti, Sr, Ba, La, Pr, Ce, Nd, Eu, Pb) concentrations, and Pb-isotope compositions in plagioclase from eight dome-dacite samples collected from the 2004-5 eruption of Mount St. Helens and, for comparison, from three dome samples from 1981-85. For 2004-5 samples, plagioclase phenocrysts...
Authors
Adam J. R. Kent, Michael C. Rowe, Carl R. Thornber, John S. Pallister
238U-230Th-226Ra Disequilibria in Dacite and Plagioclase from the 2004–2005 Eruption of Mount St. Helens 238U-230Th-226Ra Disequilibria in Dacite and Plagioclase from the 2004–2005 Eruption of Mount St. Helens
Uranium-series disequilibria in whole-rock samples and mineral separates provide unique insights into the time scales and processes of magma mixing, storage, and crystallization. We present 238U- 230Th-226Ra data for whole-rock dacite and gouge samples and for plagioclase separated from two dacite samples, all erupted from Mount St. Helens between October 2004 and April 2005. We also...
Authors
Kari M. Cooper, Carrie T. Donnelly
Constraints on the size, overpressure, and volatile content of the Mount St. Helens magma system from geodetic and dome-growth measurements during the 2004-2006+ eruption Constraints on the size, overpressure, and volatile content of the Mount St. Helens magma system from geodetic and dome-growth measurements during the 2004-2006+ eruption
During the ongoing eruption at Mount St. Helens, Washington, lava has extruded continuously at a rate that decreased from ~7-9 m3 /s in October 2004 to 1-2 m3 /s by December 2005. The volume loss in the magma reservoir estimated from the geodetic data, 1.6-2.7×10 7 m3 , is only a few tens of percent of the 7.5×10 7 m3 volume that had erupted by the end of 2005.
Authors
Larry G. Mastin, Evelyn Roeloffs, Nick M. Beeler, James E. Quick
Growth of the 2004-2006 lava-dome complex at Mount St. Helens, Washington Growth of the 2004-2006 lava-dome complex at Mount St. Helens, Washington
The eruption of Mount St. Helens from 2004 to 2006 has comprised extrusion of solid lava spines whose growth patterns were shaped by a large space south of the 1980-86 dome that was occupied by the unique combination of glacial ice, concealed subglacial slopes, the crater walls, and relics of previous spines. The eruption beginning September 2004 can be divided (as of April 2006) into...
Authors
James W. Vallance, David J. Schneider, Steve P. Schilling
Radar interferometry observations of surface displacements during pre- and coeruptive periods at Mount St. Helens, Washington, 1992-2005 Radar interferometry observations of surface displacements during pre- and coeruptive periods at Mount St. Helens, Washington, 1992-2005
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...
Authors
Michael P. Poland, Zhong Lu
Non-USGS Publications**
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
Filter Total Items: 70
Extrusion rate of the Mount St. Helens lava dome estimated from terrestrial imagery, November 2004-December 2005 Extrusion rate of the Mount St. Helens lava dome estimated from terrestrial imagery, November 2004-December 2005
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...
Authors
Jon J. Major, Cole G. Kingsbury, Michael P. Poland, Richard G. LaHusen
Trace element and Pb isotope composition of plagioclase from dome samples from the 2004-2005 eruption of Mount St. Helens, Washington Trace element and Pb isotope composition of plagioclase from dome samples from the 2004-2005 eruption of Mount St. Helens, Washington
We report the results of in-situ laser ablation ICP–MS analyses of anorthite content, trace-element (Li, Ti, Sr, Ba, La, Pr, Ce, Nd, Eu, Pb) concentrations, and Pb-isotope compositions in plagioclase from eight dome-dacite samples collected from the 2004-5 eruption of Mount St. Helens and, for comparison, from three dome samples from 1981-85. For 2004-5 samples, plagioclase phenocrysts...
Authors
Adam J. R. Kent, Michael C. Rowe, Carl R. Thornber, John S. Pallister
238U-230Th-226Ra Disequilibria in Dacite and Plagioclase from the 2004–2005 Eruption of Mount St. Helens 238U-230Th-226Ra Disequilibria in Dacite and Plagioclase from the 2004–2005 Eruption of Mount St. Helens
Uranium-series disequilibria in whole-rock samples and mineral separates provide unique insights into the time scales and processes of magma mixing, storage, and crystallization. We present 238U- 230Th-226Ra data for whole-rock dacite and gouge samples and for plagioclase separated from two dacite samples, all erupted from Mount St. Helens between October 2004 and April 2005. We also...
Authors
Kari M. Cooper, Carrie T. Donnelly
Constraints on the size, overpressure, and volatile content of the Mount St. Helens magma system from geodetic and dome-growth measurements during the 2004-2006+ eruption Constraints on the size, overpressure, and volatile content of the Mount St. Helens magma system from geodetic and dome-growth measurements during the 2004-2006+ eruption
During the ongoing eruption at Mount St. Helens, Washington, lava has extruded continuously at a rate that decreased from ~7-9 m3 /s in October 2004 to 1-2 m3 /s by December 2005. The volume loss in the magma reservoir estimated from the geodetic data, 1.6-2.7×10 7 m3 , is only a few tens of percent of the 7.5×10 7 m3 volume that had erupted by the end of 2005.
Authors
Larry G. Mastin, Evelyn Roeloffs, Nick M. Beeler, James E. Quick
Growth of the 2004-2006 lava-dome complex at Mount St. Helens, Washington Growth of the 2004-2006 lava-dome complex at Mount St. Helens, Washington
The eruption of Mount St. Helens from 2004 to 2006 has comprised extrusion of solid lava spines whose growth patterns were shaped by a large space south of the 1980-86 dome that was occupied by the unique combination of glacial ice, concealed subglacial slopes, the crater walls, and relics of previous spines. The eruption beginning September 2004 can be divided (as of April 2006) into...
Authors
James W. Vallance, David J. Schneider, Steve P. Schilling
Radar interferometry observations of surface displacements during pre- and coeruptive periods at Mount St. Helens, Washington, 1992-2005 Radar interferometry observations of surface displacements during pre- and coeruptive periods at Mount St. Helens, Washington, 1992-2005
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...
Authors
Michael P. Poland, Zhong Lu
Non-USGS Publications**
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.