Publications
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Age of the Rockland tephra, western USA Age of the Rockland tephra, western USA
The age of the Rockland tephra, which includes an ash-flow tuff south and west of Lassen Peak in northern California and a widespread ash-fall deposit that produced a distinct stratigraphic marker in western North America, is constrained to 565,000 to 610,000 yr by 40Ar/39Ar and U–Pb dating. 40Ar/39Ar ages on plagioclase from pumice in the Rockland have a weighted mean age of 609,000 ±...
Authors
M. A. Lanphere, D.E. Champion, M.A. Clynne, J. B. Lowenstern, A.M. Sarna-Wojcicki, J. L. Wooden
Precise relocation of earthquakes following the 15 June 1991 eruption of Mount Pinatubo (Philippines) Precise relocation of earthquakes following the 15 June 1991 eruption of Mount Pinatubo (Philippines)
The 15 June 1991 climactic eruption of Mount Pinatubo (Philippines) was followed by intense seismicity that remained at a high level for several months. We located 10,839 events recorded between 1 July and mid-December 1991. In contrast to the preeruptive seismicity which was focused in two groups below the summit area, posteruptive events were widely distributed below and around the...
Authors
J. Battaglia, C.H. Thurber, J.-L. Got, C.A. Rowe, R.A. White
Oxidized sulfur-rich mafic magma at Mount Pinatubo, Philippines Oxidized sulfur-rich mafic magma at Mount Pinatubo, Philippines
Basaltic fragments enclosed in andesitic dome lavas and pyroclastic flows erupted during the early stages of the 1991 eruption of Mount Pinatubo, Philippines, contain amphiboles that crystallized during the injection of mafic magma into a dacitic magma body. The amphiboles contain abundant melt inclusions, which recorded the mixing of andesitic melt in the mafic magma and rhyolitic melt...
Authors
J.C.M. de Hoog, K.H. Hattori, R. Hoblitt
Non-double-couple microearthquakes at Long Valley caldera, California, provide evidence for hydraulic fracturing Non-double-couple microearthquakes at Long Valley caldera, California, provide evidence for hydraulic fracturing
Most of 26 small (0.4≲M≲3.1) microearthquakes at Long Valley caldera in mid-1997, analyzed using data from a dense temporary network of 69 digital three-component seismometers, have significantly non-double-couple focal mechanisms, inconsistent with simple shear faulting. We determined their mechanisms by inverting P- and S-wave polarities and amplitude ratios using linear-programming...
Authors
G.R. Foulger, B.R. Julian, D.P. Hill, A.D. Pitt, P.E. Malin, E. Shalev
1999 Volcanic activity in Alaska and Kamchatka: Summary of events and response of the Alaska Volcano Observatory 1999 Volcanic activity in Alaska and Kamchatka: Summary of events and response of the Alaska Volcano Observatory
The Alaska Volcano Observatory (AVO) monitors 41 historically active volcanoes along the Aleutian Arc. Twenty are seismically monitored and for the rest, the AVO monitoring program relies mainly on daily analysis of satellite images, pilot reports, and observations of local residents and ship's crews. In 1999, AVO responded to eruptive activity or suspect volcanic activity at 7 volcanic...
Authors
Robert G. McGimsey, Christina A. Neal, Olga Girina
A 2000-year-long record of climate from the Gulf of California A 2000-year-long record of climate from the Gulf of California
No abstract available.
Authors
John A. Barron, David Bukry, James L. Bischoff
Mechanics of geological materials Mechanics of geological materials
No abstract available.
Authors
Richard M. Iverson
Large floods in the United States: Where they happen and why Large floods in the United States: Where they happen and why
The spatial distribution of large gaged floods throughout the United States shows that the locations of most of the largest flows are related to specific combinations of regional climatology, topography, and basin size. Key factors include the general northward trend of decreasing atmospheric moisture, proximity to oceanic moisture sources such as the Pacific Ocean and the Gulf of Mexico...
Authors
Jim E. O'Connor, John E. Costa
Effects of land subsidence in the Greater Houston Area Effects of land subsidence in the Greater Houston Area
No abstract available.
Authors
Devin L. Galloway, Laura S. Coplin, Steven E. Ingebritsen
The Pu‘u ‘Ō‘ō-Kūpaianaha eruption of Kīlauea Volcano, Hawai‘i: The first 20 years The Pu‘u ‘Ō‘ō-Kūpaianaha eruption of Kīlauea Volcano, Hawai‘i: The first 20 years
The Pu'u 'O'o-Kupaianaha eruption started on January 3, 1983. The ensuing 20-year period of nearly continuous eruption is the longest at Kilauea Volcano since the famous lava-lake activity of the 19th century. No rift-zone eruption in more than 600 years even comes close to matching the duration and volume of activity of these past two decades. Fortunately, such a landmark event came...
When models meet managers: Examples from geomorphology When models meet managers: Examples from geomorphology
No abstract available.
Authors
Peter R. Wilcock, John C. Schmidt, M. Gordon Wolman, William E. Dietrich, DeWitt Dominick, Martin W. Doyle, Gordon E. Grant, Richard M. Iverson, David R. Montgomery, Thomas C. Pierson, Steven P. Schilling, Raymond C. Wilson