Publications
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An updated global earthquake catalogue for stable continental regions: Reassessing the correlation with ancient rifts An updated global earthquake catalogue for stable continental regions: Reassessing the correlation with ancient rifts
We present an updated global earthquake catalogue for stable continental regions (SCRs; i.e. intraplate earthquakes) that is available on the Internet. Our database contains information on location, magnitude, seismic moment and focal mechanisms for over 1300 M (moment magnitude) ≥ 4.5 historic and instrumentally recorded crustal events. Using this updated earthquake database in...
Authors
S.M. Schulte, Walter D. Mooney
The controlling effect of viscous dissipation on magma flow in silicic conduits The controlling effect of viscous dissipation on magma flow in silicic conduits
Nearly all volcanic conduit models assume that flow is Newtonian and isothermal. Such models predict that, during high-flux silicic eruptions, gradients in pressure with depth increase upward as magma accelerates and becomes more viscous, leading to extremely low pressure and fragmentation at a depth of kilometers below the surface. In this paper I show that shear heating, also known as...
Authors
L.G. Mastin
Thermal infrared and visual observations of a water ice lag in the Mars southern summer Thermal infrared and visual observations of a water ice lag in the Mars southern summer
We present thermal infrared and visual evidence for the existence of water ice lags in the early southern summer. The observed H2O‐ice lags lay in and near a chasma and appears to survive between 6–8 sols past the sublimation of the CO2. Possible sources of the H2O that compose the lag are (1) atmospheric H2O that is incorporated into the seasonal cap during condensation, (2) cold...
Authors
Timothy N. Titus
Regulation of landslide motion by dilatancy and pore pressure feedback Regulation of landslide motion by dilatancy and pore pressure feedback
A new mathematical model clarifies how diverse styles and rates of landslide motion can result from regulation of Coulomb friction by dilation or contraction of water‐saturated basal shear zones. Normalization of the model equations shows that feedback due to coupling between landslide motion, shear zone volume change, and pore pressure change depends on a single dimensionless parameter...
Authors
R.M. Iverson
The Zamama-Thor region of Io: Insights from a synthesis of mapping, topography, and Galileo spacecraft data The Zamama-Thor region of Io: Insights from a synthesis of mapping, topography, and Galileo spacecraft data
We have studied data from the Galileo spacecraft's three remote sensing instruments (Solid-State Imager (SSI), Near-Infrared Mapping Spectrometer (NIMS), and Photopolarimeter-Radiometer (PPR)) covering the Zamama–Thor region of Io's antijovian hemisphere, and produced a geomorphological map of this region. This is the third of three regional maps we are producing from the Galileo...
Authors
David A. Williams, Laszlo P. Keszthelyi, Paul M. Schenk, Moses P. Milazzo, Rosaly Lopes, Julie A. Rathbun, Ronald Greeley
Mars exploration rover geologic traverse by the spirit rover in the plains of Gusev crater, Mars Mars exploration rover geologic traverse by the spirit rover in the plains of Gusev crater, Mars
The Spirit rover completed a 2.5 km traverse across gently sloping plains on the floor of Gusev crater from its location on the outer rim of Bonneville crater to the lower slopes of the Columbia Hills, Mars. Using the Athena suite of instruments in a transect approach, a systematic series of overlapping panoramic mosaics, remote sensing observations, surface analyses, and trenching...
Authors
L.S. Crumpler, S. W. Squyres, R. E. Arvidson, J.F. Bell, D. Blaney, N.A. Cabrol, P. R. Christensen, D.J. DesMarais, J.D. Farmer, R. Fergason, M.P. Golombek, F.D. Grant, J. A. Grant, R. Greeley, B. Hahn, Kenneth E. Herkenhoff, J.A. Hurowitz, A.T. Knudson, G. A. Landis, R. Li, J. Maki, H.Y. McSween, D. W. Ming, J.E. Moersch, M.C. Payne, J.W. Rice, L. Richter, S. W. Ruff, M. Sims, S.D. Thompson, N. Tosca, A. Wang, P. Whelley, S.P. Wright, M.B. Wyatt
THEMIS VIS and IR observations of a high-altitude Martian dust devil THEMIS VIS and IR observations of a high-altitude Martian dust devil
The Mars Odyssey Thermal Emission Imaging System (THEMIS) imaged a Martian dust devil in both visible and thermal-infrared wavelengths on January 30, 2004. We believe this is the first documented infrared observation of an extraterrestrial dust devil, and the highest to be directly observed at more than 16 kilometers above the equatorial geoid of Mars. This dust devil measured over 700...
Authors
Glen Cushing, Timothy N. Titus, Phillip R. Christensen
Source process of a long-period event at Kilauea volcano, Hawaii Source process of a long-period event at Kilauea volcano, Hawaii
We analyse a long-period (LP) event observed by a dense seismic network temporarily operated at Kilauea volcano, Hawaii, in 1996. We systematically perform spectral analyses, waveform inversions and forward modeling of the LP event to quantify its source process. Spectral analyses identify two dominant spectral frequencies at 0.6 and 1.3 Hz with associated Q values in the range 10-20...
Authors
Hiroyuki Kumagai, B. A. Chouet, P.B. Dawson
Evolution of melt-vapor surface tension in silicic volcanic systems: Experiments with hydrous melts Evolution of melt-vapor surface tension in silicic volcanic systems: Experiments with hydrous melts
We evaluate the melt‐vapor surface tension (σ) of natural, water‐saturated dacite melt at 200 MPa, 950–1055°C, and 4.8–5.7 wt % H2O. We experimentally determine the critical supersaturation pressure for bubble nucleation as a function of dissolved water and then solve for σ at those conditions using classical nucleation theory. The solutions obtained give dacite melt‐vapor surface...
Authors
M. Mangan, T. Sisson
Magma generation at a large, hyperactive silicic volcano (Taupo, New Zealand) revealed by U-Th and U-Pb systematics in zircons Magma generation at a large, hyperactive silicic volcano (Taupo, New Zealand) revealed by U-Th and U-Pb systematics in zircons
Young (
Authors
B. L. A. Charlier, C. J. N. Wilson, J. B. Lowenstern, S. Blake, P.W. van Calsteren, J.P. Davidson
Source mechanism of Vulcanian degassing at Popocatépetl Volcano, Mexico, determined from waveform inversions of very long period signals Source mechanism of Vulcanian degassing at Popocatépetl Volcano, Mexico, determined from waveform inversions of very long period signals
The source mechanism of very long period (VLP) signals accompanying volcanic degassing bursts at Popocatépetl is analyzed in the 15–70 s band by minimizing the residual error between data and synthetics calculated for a point source embedded in a homogeneous medium. The waveforms of two eruptions (23 April and 23 May 2000) representative of mild Vulcanian activity are well reproduced by...
Authors
Bernard A. Chouet, Phillip B. Dawson, Alejandra Arciniega-Ceballos
Log of Trench 04A across the Hayward Fault at Tyson's Lagoon (Tule Pond), Fremont, Alameda County, California Log of Trench 04A across the Hayward Fault at Tyson's Lagoon (Tule Pond), Fremont, Alameda County, California
This publication makes available a detailed trench log (sheets 1 and 2) of a 110-m trench we excavated in 2004 across a tectonic sag pond in the Hayward fault zone. Also included are revised stratigraphic unit descriptions from this fifth field season of subsurface investigation of the Hayward fault at Tyson's Lagoon (Tule Pond). Preliminary findings based on fieldwork done in 2000 have...
Authors
James J. Lienkaemper, Patrick L. Williams, Robert R. Sickler, Thomas E. Fumal