Publications
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Dynamic rupture modeling of the transition from thrust to strike-slip motion in the 2002 Denali fault earthquake, Alaska Dynamic rupture modeling of the transition from thrust to strike-slip motion in the 2002 Denali fault earthquake, Alaska
We use three-dimensional dynamic (spontaneous) rupture models to investigate the nearly simultaneous ruptures of the Susitna Glacier thrust fault and the Denali strike-slip fault. With the 1957 Mw 8.3 Gobi-Altay, Mongolia, earthquake as the only other well-documented case of significant, nearly simultaneous rupture of both thrust and strike-slip faults, this feature of the 2002 Denali...
Authors
Brad T. Aagaard, G. Anderson, K.W. Hudnut
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
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
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
Pancam multispectral imaging results from the Spirit Rover at Gusev crater Pancam multispectral imaging results from the Spirit Rover at Gusev crater
Panoramic Camera images at Gusev crater reveal a rock-strewn surface interspersed with high- to moderate-albedo fine-grained deposits occurring in part as drifts or in small circular swales or hollows. Optically thick coatings of fine-grained ferric iron-rich dust dominate most bright soil and rock surfaces. Spectra of some darker rock surfaces and rock regions exposed by brushing or...
Authors
J.F. Bell, S. W. Squyres, R. E. Arvidson, H.M. Arneson, D. Bass, D. Blaney, N. Cabrol, W. Calvin, J. Farmer, W. H. Farrand, W. Goetz, M. Golombek, J. A. Grant, R. Greeley, E. Guinness, A. G. Hayes, M.Y.H. Hubbard, Kenneth E. Herkenhoff, M. J. Johnson, J. R. Johnson, J. Joseph, K.M. Kinch, M.T. Lemmon, R. Li, M.B. Madsen, J.N. Maki, M. Malin, E. McCartney, S. McLennan, H.Y. McSween, D. W. Ming, J.E. Moersch, R.V. Morris, E.Z.N. Dobrea, T. J. Parker, J. Proton, J. W. Rice, F. Seelos, J. Soderblom, Laurence A. Soderblom, J. N. Sohl-Dickstein, R.J. Sullivan, M.J. Wolff, A. Wang
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
Comparison of USGS and DLR topographic models of Comet Borrelly and photometric applications Comparison of USGS and DLR topographic models of Comet Borrelly and photometric applications
Stereo analysis of images obtained during the 2001 flyby of Comet Borrelly by NASA's Deep Space 1 (DS1) probe allows us to quantify the shape and photometric behavior of the nucleus. The shape is complex, with planar facets corresponding to the dark, mottled regions of the surface whereas the bright, smooth regions are convexly curved. The photometric as well as textural differences...
Authors
Randolph L. Kirk, Elpitha Howington-Kraus, Laurence A. Soderblom, Bernd Giese, Jurgen Oberst
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
Soils of eagle crater and Meridiani Planum at the opportunity Rover landing site Soils of eagle crater and Meridiani Planum at the opportunity Rover landing site
The soils at the Opportunity site are fine-grained basaltic sands mixed with dust and sulfate-rich outcrop debris. Hematite is concentrated in spherules eroded from the strata. Ongoing saltation exhumes the spherules and their fragments, concentrating them at the surface. Spherules emerge from soils coated, perhaps from subsurface cementation, by salts. Two types of vesicular clasts may...
Authors
Laurence A. Soderblom, R. C. Anderson, R. E. Arvidson, J.F. Bell, N.A. Cabrol, W. Calvin, P. R. Christensen, B. C. Clark, T. Economou, B.L. Ehlmann, W. H. Farrand, D. Fike, Ralf Gellert, T.D. Glotch, M.P. Golombek, R. Greeley, J.P. Grotzinger, Kenneth E. Herkenhoff, D.J. Jerolmack, J. R. Johnson, B. Jolliff, C. Klingelhofer, A.H. Knoll, Z.A. Learner, R. Li, M. C. Malin, S. M. McLennan, H.Y. McSween, D. W. Ming, R.V. Morris, J. W. Rice, L. Richter, R. Rieder, D. Rodionov, C. Schroder, F.P. Seelos, J.M. Soderblom, S. W. Squyres, R. Sullivan, W.A. Watters, C.M. Weitz, M.B. Wyatt, A. Yen, J. Zipfel
Holocene reef accretion: southwest Molokai, Hawaii, U.S.A. Holocene reef accretion: southwest Molokai, Hawaii, U.S.A.
Two reef systems off south Molokai, Hale O Lono and Hikauhi (separated by only 10 km), show strong and fundamental differences in modern ecosystem structure and Holocene accretion history that reflect the influence of wave-induced near-bed shear stresses on reef development in Hawaii. Both sites are exposed to similar impacts from south, Kona, and trade-wind swell. However, the Hale O...
Authors
Mary S. Engels, Charles H. Fletcher, Michael E. Field, Curt D. Storlazzi, Eric E. Grossman, John J.B. Rooney, Christopher L. Conger, Craig Glenn
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