Publications
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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
Reaction rim growth on olivine in silicic melts: Implications for magma mixing Reaction rim growth on olivine in silicic melts: Implications for magma mixing
Finely crystalline amphibole or pyroxene rims that form during reaction between silicic host melt and cognate olivine xenocrysts, newly introduced during magma mixing events, can provide information about the timing between mixing and volcanic eruptions. We investigated rim growth experimentally by placing forsteritic olivine in rhyolitic and rhyodacitic melts for times between 25 and...
Authors
Michelle L. Coombs, James E. Gardner
Stress field variations in the Swiss Alps and the northern Alpine foreland derived from inversion of fault plane solutions Stress field variations in the Swiss Alps and the northern Alpine foreland derived from inversion of fault plane solutions
This study is devoted to a systematic analysis of the state of stress of the central European Alps and northern Alpine foreland in Switzerland based on focal mechanisms of 138 earthquakes with magnitudes between 1 and 5. The most robust feature of the results is that the azimuth of the minimum compressive stress, S3, is generally well constrained for all data subsets and always lies in...
Authors
U. Kastrup, M.L. Zoback, N. Deichmann, Kenneth F. Evans, D. Giardini, A.J. Michael
Evidence for liquefaction identified in peeled slices of Holocene deposits along the Lower Columbia River, Washington Evidence for liquefaction identified in peeled slices of Holocene deposits along the Lower Columbia River, Washington
Peels made from 10 geoslices beneath a riverbank at Washington's Hunting Island, 45 km inland from the Pacific coast, aid in identifying sand that liquefied during prehistoric earthquakes of estimated magnitude 8-9 at the Cascadia subduction zone. Each slice was obtained by driving sheetpile and a shutter plate to depths of 6-8 m. The resulting sample, as long as 8 m, had a trapezoidal...
Authors
K. Takada, B.F. Atwater
Surface changes on Io during the Galileo mission Surface changes on Io during the Galileo mission
A careful survey of Galileo SSI global monitoring images revealed more than 80 apparent surface changes that took place on Io during the 5 year period of observation, ranging from giant plume deposits to subtle changes in the color or albedo of Patera surfaces. Explosive volcanic activity was discovered at four previously unrecognized centers: an unnamed patera to the south of Karei that...
Authors
Paul E. Geissler, Alfred McEwen, Cynthia B. Phillips, Laszlo P. Keszthelyi, John Spencer
The role of water in gas hydrate dissociation The role of water in gas hydrate dissociation
When raised to temperatures above the ice melting point, gas hydrates release their gas in well-defined, reproducible events that occur within self-maintained temperature ranges slightly below the ice point. This behavior is observed for structure I (carbon dioxide, methane) and structure II gas hydrates (methane-ethane, and propane), including those formed with either H2O- or D2O-host...
Authors
S. Circone, L.A. Stern, S. H. Kirby
The final Galileo SSI observations of Io: Orbits G28-I33 The final Galileo SSI observations of Io: Orbits G28-I33
We present the observations of Io acquired by the Solid State Imaging (SSI) experiment during the Galileo Millennium Mission (GMM) and the strategy we used to plan the exploration of Io. Despite Galileo's tight restrictions on data volume and downlink capability and several spacecraft and camera anomalies due to the intense radiation close to Jupiter, there were many successful SSI...
Authors
Elizabeth P. Turtle, Laszlo P. Keszthelyi, Alfred S. McEwen, Jani Radebaugh, Moses P. Milazzo, Damon P. Simonelli, Paul E. Geissler, David A. Williams, Jason Perry, Windy L. Jaeger, Kenneth P. Klaasen, H. Herbert Breneman, Tilmann Denk, Cynthia B. Phillips
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
Crustal structure of the northern margin of the eastern Tien Shan, China, and its tectonic implications for the 1906 M~7.7 Manas earthquake Crustal structure of the northern margin of the eastern Tien Shan, China, and its tectonic implications for the 1906 M~7.7 Manas earthquake
The Tien Shan orogenic belt is the most active intracontinental mountain belt in the world. We describe an 86-km-long N–S-trending deep seismic reflection profile (which passes through the southern Junggar basin) located on the northeastern Tien Shan piedmont. Two distinct anticlines beneath the northern margin of the Tien Shan are clearly imaged in the seismic section. In addition, we...
Authors
Chun-Yong Wang, Zhu-En Yang, Hai Luo, Walter D. Mooney
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
Localization and physical properties experiments conducted by Spirit at Gusev crater Localization and physical properties experiments conducted by Spirit at Gusev crater
The precise location and relative elevation of Spirit during its traverses from the Columbia Memorial station to Bonneville crater were determined with bundle-adjusted retrievals from rover wheel turns, suspension and tilt angles, and overlapping images. Physical properties experiments show a decrease of 0.2% per Mars solar day in solar cell output resulting from deposition of airborne...
Authors
R. E. Arvidson, R. C. Anderson, P. Bartlett, J.F. Bell, D. Blaney, P. R. Christensen, P. Chu, L. Crumpler, K. Davis, B.L. Ehlmann, R. Fergason, M.P. Golombek, S. Gorevan, J. A. Grant, R. Greeley, E.A. Guinness, A. F. C. Haldemann, Kenneth E. Herkenhoff, J. Johnson, G. Landis, R. Li, R. Lindemann, H. McSween, D. W. Ming, T. Myrick, L. Richter, F.P. Seelos, S. W. Squyres, R.J. Sullivan, A. Wang, Jim Wilson