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
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
Evolving magma storage conditions beneath Mount St. Helens inferred from chemical variations in melt inclusions from the 1980-1986 and current (2004-2006) eruptions Evolving magma storage conditions beneath Mount St. Helens inferred from chemical variations in melt inclusions from the 1980-1986 and current (2004-2006) eruptions
Major element, trace element, and volatile concentrations in 187 glassy melt inclusions and 25 groundmass glasses from the 1980-86 eruption of Mount St. Helens are presented, together with 103 analyses of touching FE-Ti oxide pairs from the same samples. These data are used to evaluate the temporal evolution of the magmatic plumbing system beneath the volcano during 1980-86 and so...
Authors
Jon Blundy, Katharine V. Cashman, Kim Berlo
Use of thermal infrared imaging for monitoring renewed dome growth at Mount St. Helens, 2004 Use of thermal infrared imaging for monitoring renewed dome growth at Mount St. Helens, 2004
A helicopter-mounted thermal imaging radiometer documented the explosive vent-clearing and effusive phases of the eruption of Mount St. Helens in 2004. A gyrostabilized gimbal controlled by a crew member housed the radiometer and an optical video camera attached to the nose of the helicopter. Since October 1, 2004, the system has provided thermal and video observations of dome growth...
Authors
David J. Schneider, James W. Vallance, Rick L. Wessels, Matthew Logan, Michael S. Ramsey
From dome to dust: shallow crystallization and fragmentation of conduit magma during the 2004-2006 dome extrusion of Mount St. Helens, Washington From dome to dust: shallow crystallization and fragmentation of conduit magma during the 2004-2006 dome extrusion of Mount St. Helens, Washington
An unusual feature of the 2004-6 eruptive activity of Mount St. Helens has been the continuous growth of successive spines that are mantled by thick fault gouge. Fault gouge formation requires, first, solidification of ascending magma within the conduit, then brittle fragmentation and cataclastic flow. We document these processes through field relations, hand samples, and thin-section
Authors
Katharine V. Cashman, Carl R. Thornber, John S. Pallister
Chemistry, mineralogy, and petrology of amphibole in Mount St. Helens 2004-2006 dacite Chemistry, mineralogy, and petrology of amphibole in Mount St. Helens 2004-2006 dacite
Textural, compositional, and mineralogical data are reported and interpreted for a large population of clinoamphibole phenocrysts in 22 samples from the seven successive dacite spines erupted at Mount St. Helens between October 2004 and January 2006. Despite the uniformity in bulk composition of magma erupted since 2004, there is striking textural and compositional diversity among...
Authors
Carl R. Thornber, John S. Pallister, Heather Lowers, Michael C. Rowe, Charlie Mandeville, Gregory P. Meeker
Frictional properties of the Mount St. Helens gouge Frictional properties of the Mount St. Helens gouge
Frictional properties of gouge bounding the solid dacite plug that extruded at Mount St. Helens during 2004 and 2005 may have caused stick-slip upward motion of the plug and associated seismicity. Laboratory experiments were performed with a ring-shear device to test the dependence of the peak and steady-state frictional strength of the gouge on shearing rate and hold time. A remolded...
Authors
Peter L. Moore, Neal R. Iverson, Richard M. Iverson
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
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
Evolving magma storage conditions beneath Mount St. Helens inferred from chemical variations in melt inclusions from the 1980-1986 and current (2004-2006) eruptions Evolving magma storage conditions beneath Mount St. Helens inferred from chemical variations in melt inclusions from the 1980-1986 and current (2004-2006) eruptions
Major element, trace element, and volatile concentrations in 187 glassy melt inclusions and 25 groundmass glasses from the 1980-86 eruption of Mount St. Helens are presented, together with 103 analyses of touching FE-Ti oxide pairs from the same samples. These data are used to evaluate the temporal evolution of the magmatic plumbing system beneath the volcano during 1980-86 and so...
Authors
Jon Blundy, Katharine V. Cashman, Kim Berlo
Use of thermal infrared imaging for monitoring renewed dome growth at Mount St. Helens, 2004 Use of thermal infrared imaging for monitoring renewed dome growth at Mount St. Helens, 2004
A helicopter-mounted thermal imaging radiometer documented the explosive vent-clearing and effusive phases of the eruption of Mount St. Helens in 2004. A gyrostabilized gimbal controlled by a crew member housed the radiometer and an optical video camera attached to the nose of the helicopter. Since October 1, 2004, the system has provided thermal and video observations of dome growth...
Authors
David J. Schneider, James W. Vallance, Rick L. Wessels, Matthew Logan, Michael S. Ramsey
From dome to dust: shallow crystallization and fragmentation of conduit magma during the 2004-2006 dome extrusion of Mount St. Helens, Washington From dome to dust: shallow crystallization and fragmentation of conduit magma during the 2004-2006 dome extrusion of Mount St. Helens, Washington
An unusual feature of the 2004-6 eruptive activity of Mount St. Helens has been the continuous growth of successive spines that are mantled by thick fault gouge. Fault gouge formation requires, first, solidification of ascending magma within the conduit, then brittle fragmentation and cataclastic flow. We document these processes through field relations, hand samples, and thin-section
Authors
Katharine V. Cashman, Carl R. Thornber, John S. Pallister
Chemistry, mineralogy, and petrology of amphibole in Mount St. Helens 2004-2006 dacite Chemistry, mineralogy, and petrology of amphibole in Mount St. Helens 2004-2006 dacite
Textural, compositional, and mineralogical data are reported and interpreted for a large population of clinoamphibole phenocrysts in 22 samples from the seven successive dacite spines erupted at Mount St. Helens between October 2004 and January 2006. Despite the uniformity in bulk composition of magma erupted since 2004, there is striking textural and compositional diversity among...
Authors
Carl R. Thornber, John S. Pallister, Heather Lowers, Michael C. Rowe, Charlie Mandeville, Gregory P. Meeker
Frictional properties of the Mount St. Helens gouge Frictional properties of the Mount St. Helens gouge
Frictional properties of gouge bounding the solid dacite plug that extruded at Mount St. Helens during 2004 and 2005 may have caused stick-slip upward motion of the plug and associated seismicity. Laboratory experiments were performed with a ring-shear device to test the dependence of the peak and steady-state frictional strength of the gouge on shearing rate and hold time. A remolded...
Authors
Peter L. Moore, Neal R. Iverson, Richard M. Iverson
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.