Publications
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Decompression experiments identify kinetic controls on explosive silicic eruptions Decompression experiments identify kinetic controls on explosive silicic eruptions
Eruption intensity is largely controlled by decompression‐induced release of water‐rich gas dissolved in magma. It is not simply the amount of gas that dictates how forcefully magma is propelled upwards during an eruption, but also the rate of degassing, which is partly a function of the supersaturation pressure (ΔPcritical) triggering gas bubble nucleation. High temperature and pressure
Authors
M. T. Mangan, T. W. Sisson, W.B. Hankins
Ultra-high chlorine in submarine Kı̄lauea glasses: Evidence for direct assimilation of brine by magma Ultra-high chlorine in submarine Kı̄lauea glasses: Evidence for direct assimilation of brine by magma
Basaltic glass grains from the submarine south flank of Kı̄lauea, Hawai′i, have Cl concentrations of 0.01–1.68 wt%, the latter being the highest Cl content yet recorded for a Hawaiian glass. The high-Cl glass grains are products of brine assimilation by tholeiite magma. The glasses are grains in a sandstone clast from bedded breccias draping the southwestern margin of Kı̄lauea’s...
Authors
Michelle L. Coombs, Thomas W. Sisson, Jun-Ichi Kimura
Growth and collapse of Waianae volcano, Hawaii, as revealed by exploration of its submarine flanks Growth and collapse of Waianae volcano, Hawaii, as revealed by exploration of its submarine flanks
Wai‘anae Volcano comprises the western half of O‘ahu Island, but until recently little was known about the submarine portion of this volcano. Seven new submersible dives, conducted in 2001 and 2002, and multibeam bathymetry offshore of Wai‘anae provide evidence pertaining to the overall growth of the volcano's edifice as well as the timing of collapses that formed the Wai‘anae slump...
Authors
Michelle L. Coombs, David A. Clague, Gregory F. Moore, Brian L. Cousens
The Rock Elm meteorite impact structure, Wisconsin: Geology and shock-metamorphic effects in quartz The Rock Elm meteorite impact structure, Wisconsin: Geology and shock-metamorphic effects in quartz
The Rock Elm structure in southwest Wisconsin is an anomalous circular area of highly deformed rocks, ∼6.5 km in diameter, located in a region of virtually horizontal undeformed sedimentary rocks. Shock-produced planar microstructures (PMs) have been identified in quartz grains in several lithologies associated with the structure: sandstones, quartzite pebbles, and breccia. Two distinct...
Authors
B.M. French, W.S. Cordua, J. B. Plescia
Role of a large marine protected area for conserving landscape attributes of sand habitats on Georges Bank (NW Atlantic) Role of a large marine protected area for conserving landscape attributes of sand habitats on Georges Bank (NW Atlantic)
Mobile fishing gear reduces seafloor habitat complexity through the removal of structure-building fauna, e.g. emergent organisms that create pits and burrows, as well as by smoothing of sedimentary bedforms (e.g. sand ripples). In this study, we compared the relative abundance of microhabitat features (the scale at which individual fish associate with seafloor habitat) inside and outside...
Authors
J. Lindholm, P. Auster, P. Valentine
The opportunity Rover's Athena science investigation at Meridiani Planum, Mars The opportunity Rover's Athena science investigation at Meridiani Planum, Mars
The Mars Exploration Rover Opportunity has investigated the landing site in Eagle crater and the nearby plains within Meridiani Planum. The soils consist of fine-grained basaltic sand and a surface lag of hematite-rich spherules, spherule fragments, and other granules. Wind ripples are common. Underlying the thin soil layer, and exposed within small impact craters and troughs, are flat...
Authors
S. W. Squyres, R. E. Arvidson, J.F. Bell, J. Bruckner, N.A. Cabrol, W. Calvin, M. H. Carr, P. R. Christensen, B. C. Clark, L. Crumpler, D.J. Des Marais, C. D'Uston, T. Economou, J. Farmer, W. Farrand, W. Folkner, M. Golombek, S. Gorevan, J. A. Grant, R. Greeley, J. Grotzinger, L. Haskin, Kenneth E. Herkenhoff, S. Hviid, J. Johnson, G. Klingelhofer, A.H. Knoll, G. Landis, M. Lemmon, R. Li, M.B. Madsen, M. C. Malin, S. M. McLennan, H.Y. McSween, D. W. Ming, J. Moersch, R.V. Morris, T. Parker, J. W. Rice, L. Richter, R. Rieder, M. Sims, M. Smith, P. Smith, Laurence A. Soderblom, R. Sullivan, H. Wanke, T. Wdowiak, M. Wolff, A. Yen
Radiated energy and the rupture process of the Denali fault earthquake sequence of 2002 from broadband teleseismic body waves Radiated energy and the rupture process of the Denali fault earthquake sequence of 2002 from broadband teleseismic body waves
Displacement, velocity, and velocity-squared records of P and SH body waves recorded at teleseismic distances are analyzed to determine the rupture characteristics of the Denali fault, Alaska, earthquake of 3 November 2002 (MW 7.9, Me 8.1). Three episodes of rupture can be identified from broadband (∼0.1–5.0 Hz) waveforms. The Denali fault earthquake started as a MW 7.3 thrust event...
Authors
G. L. Choy, J. Boatwright
The Spirit Rover's Athena science investigation at Gusev crater, Mars The Spirit Rover's Athena science investigation at Gusev crater, Mars
The Mars Exploration Rover Spirit and its Athena science payload have been used to investigate a landing site in Gusev crater. Gusev is hypothesized to be the site of a former take, but no clear evidence for lacustrine sedimentation has been found to date. Instead, the dominant lithology is basalt, and the dominant geologic processes are impact events and eolian transport. Many rocks...
Authors
S. W. Squyres, R. E. Arvidson, J.F. Bell, J. Bruckner, N.A. Cabrol, W. Calvin, M. H. Carr, P. R. Christensen, B. C. Clark, L. Crumpler, D.J. Des Marais, C. D'Uston, T. Economou, J. Farmer, W. Farrand, W. Folkner, M. Golombek, S. Gorevan, J. A. Grant, R. Greeley, J. Grotzinger, L. Haskin, Kenneth E. Herkenhoff, S. Hviid, J. Johnson, G. Klingelhofer, A. Knoll, G. Landis, M. Lemmon, R. Li, M.B. Madsen, M. C. Malin, S. M. McLennan, H.Y. McSween, D. W. Ming, J. Moersch, R.V. Morris, T. Parker, J. W. Rice, L. Richter, R. Rieder, M. Sims, M. Smith, P. Smith, Laurence A. Soderblom, R. Sullivan, H. Wanke, T. Wdowiak, M. Wolff, A. Yen
Rhyodacites of Kulshan caldera, North Cascades of Washington: Postcaldera lavas that span the Jaramillo Rhyodacites of Kulshan caldera, North Cascades of Washington: Postcaldera lavas that span the Jaramillo
Kulshan caldera (4.5×8 km), at the northeast foot of Mount Baker, is filled with rhyodacite ignimbrite (1.15 Ma) and postcaldera lavas and is only the third Quaternary caldera identified in the Cascade arc. A gravity traverse across the caldera yields a steep-sided, symmetrical, complete Bouguer anomaly of −16 mGal centered over the caldera. Density considerations suggest that the...
Authors
W. Hildreth, M. A. Lanphere, D.E. Champion, J. Fierstein
Dispersal scaling from the world's rivers Dispersal scaling from the world's rivers
Although rivers provide important biogeochemical inputs to oceans, there are currently no descriptive or predictive relationships of the spatial scales of these river influences. Our combined satellite, laboratory, field and modeling results show that the coastal dispersal areas of small, mountainous rivers exhibit remarkable self-similar scaling relationships over many orders of...
Authors
J.A. Warrick, D.A. Fong
Shear wave velocity, seismic attenuation, and thermal structure of the continental upper mantle Shear wave velocity, seismic attenuation, and thermal structure of the continental upper mantle
Seismic velocity and attenuation anomalies in the mantle are commonly interpreted in terms of temperature variations on the basis of laboratory studies of elastic and anelastic properties of rocks. In order to evaluate the relative contributions of thermal and non-thermal effects on anomalies of attenuation of seismic shear waves, Q−1s, and seismic velocity, Vs, we compare global maps of...
Authors
I.M. Artemieva, M. Billien, J.-J. Leveque, Walter D. Mooney
The coefficient of friction of chrysotile gouge at seismogenic depths The coefficient of friction of chrysotile gouge at seismogenic depths
We report new strength data for the serpentine mineral chrysotile at effective normal stresses, σn between 40 and 200 MPa in the temperature range 25°-280°C. Overall, the coefficient of friction, μ (= shear stress/effective normal stress) of water-saturated chrysotile gouge increases both with increasing temperature and σn, but the rates vary and the temperature-related increases begin...
Authors
Diane E. Moore, D.A. Lockner, H. Tanaka, K. Iwata