Publications
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Late Pleistocene granodiorite source for recycled zircon and phenocrysts in rhyodacite lava at Crater Lake, Oregon Late Pleistocene granodiorite source for recycled zircon and phenocrysts in rhyodacite lava at Crater Lake, Oregon
Rhyodacite tephra and three lavas erupted ∼27 ka, interpreted to be early leaks from the climactic magma chamber of Mount Mazama, contain ubiquitous resorbed crystals (antecrysts) that were recycled from young granodiorite and related plutonic rocks of the same magmatic system. The shallow composite pluton is represented by blocks ejected in the 7.7-ka climactic eruption that formed...
Authors
C. R. Bacon, J. B. Lowenstern
Repeating coupled earthquakes at Shishaldin Volcano, Alaska Repeating coupled earthquakes at Shishaldin Volcano, Alaska
Since it last erupted in 1999, Shishaldin Volcano, Aleutian Islands, Alaska, has produced hundreds to thousands of long-period (1-2 Hz; LP) earthquakes every day with no other sign of volcanic unrest. In 2002, the earthquakes also exhibited a short-period (4-7 Hz; SP) signal occurring between 3 and 15 s before the LP phase. Although the SP phase contains higher frequencies than the LP...
Authors
J. Caplan-Auerbach, T. Petersen
DUCKS: Low cost thermal monitoring units for near-vent deployment DUCKS: Low cost thermal monitoring units for near-vent deployment
During 1999 we designed and tested a thermal monitoring system to provide a cheap, robust, modular, real-time system capable of surviving the hostile conditions encountered proximal to active volcanic vents. In November 2000 the first system was deployed at Pu'u 'O'o (Kilauea, Hawai'i) to target persistently active vents. Aside from some minor problems, such as sensor damage due to...
Authors
A. Harris, D. Pirie, K. Horton, H. Garbeil, E. Pilger, H. Ramm, R. Hoblitt, C. Thornber, M. Ripepe, E. Marchetti, P. Poggi
An integrated view of the chemistry and mineralogy of martian soils An integrated view of the chemistry and mineralogy of martian soils
The mineralogical and elemental compositions of the martian soil are indicators of chemical and physical weathering processes. Using data from the Mars Exploration Rovers, we show that bright dust deposits on opposite sides of the planet are part of a global unit and not dominated by the composition of local rocks. Dark soil deposits at both sites have similar basaltic mineralogies, and...
Authors
A. S. Yen, Ralf Gellert, C. Schroder, R.V. Morris, J.F. Bell, A.T. Knudson, B. C. Clark, D. W. Ming, J.A. Crisp, R. E. Arvidson, D. Blaney, J. Bruckner, P. R. Christensen, D.J. DesMarais, P.A. De Souza, T.E. Economou, A. Ghosh, B.C. Hahn, Kenneth E. Herkenhoff, L.A. Haskin, J.A. Hurowitz, B.L. Joliff, J. R. Johnson, G. Klingelhofer, M.B. Madsen, S. M. McLennan, H.Y. McSween, L. Richter, R. Rieder, D. Rodionov, Laurence A. Soderblom, S. W. Squyres, N.J. Tosca, A. Wang, M. Wyatt, J. Zipfel
Estimation of regional material yield from coastal landslides based on historical digital terrain modelling Estimation of regional material yield from coastal landslides based on historical digital terrain modelling
High-resolution historical (1942) and recent (1994) digital terrain models were derived from aerial photographs along the Big Sur coastline in central California to measure the long-term volume of material that enters the nearshore environment. During the 52-year measurement time period, an average of 21 000 ?? 3100 m3 km-1 a-1 of material was eroded from nine study sections distributed...
Authors
C.J. Hapke
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
Catastrophic precipitation-triggered lahar at Casita volcano, Nicaragua: Occurrence, bulking and transformation Catastrophic precipitation-triggered lahar at Casita volcano, Nicaragua: Occurrence, bulking and transformation
A catastrophic lahar began on 30 October 1998, as hurricane precipitation triggered a small flank collapse of Casita volcano, a complex and probably dormant stratovolcano. The initial rockslide‐debris avalanche evolved on the flank to yield a watery debris flood with a sediment concentration less than 60 per cent by volume at the base of the volcano. Within 2·5 km, however, the watery flow...
Authors
K. M. Scott, J.W. Vallance, N. Kerle, J.L. Macias, W. Strauch, G. Devoli
New constraints on mechanisms of remotely triggered seismicity at Long Valley Caldera New constraints on mechanisms of remotely triggered seismicity at Long Valley Caldera
Regional-scale triggering of local earthquakes in the crust by seismic waves from distant main shocks has now been robustly documented for over a decade. Some of the most thoroughly recorded examples of repeated triggering of a single site from multiple, large earthquakes are measured in geothermal fields of the western United States like Long Valley Caldera. As one of the few natural...
Authors
E. E. Brodsky, S. G. Prejean
Surface deformation associated with the March 1996 earthquake swarm at Akutan Island, Alaska, revealed by C-band ERS and L-band JERS radar interferometry Surface deformation associated with the March 1996 earthquake swarm at Akutan Island, Alaska, revealed by C-band ERS and L-band JERS radar interferometry
In March 1996, an intense earthquake swarm beneath Akutan Island, Alaska, was accompanied by extensive ground cracking but no eruption of Akutan volcano. Radar interferograms produced from L-band JERS-1 and C-band ERS-1/2 images show uplift associated with the swarm by as much as 60 cm on the western part of the island. The JERS-1 interferogram has greater coherence, especially in areas...
Authors
Z. Lu, C. Wicks, O. Kwoun, J.A. Power, D. Dzurisin
Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2004 Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2004
The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at historically active volcanoes in Alaska since 1988. The primary objectives of the seismic program are the real-time seismic...
Authors
James P. Dixon, Scott D. Stihler, John A. Power, Guy Tytgat, Steve Estes, Stephanie Prejean, John J. Sanchez, Rebecca Sanches, Stephen R. McNutt, John Paskievitch
Argon dating at and near Medicine Lake volcano, California: Results and data Argon dating at and near Medicine Lake volcano, California: Results and data
No abstract available.
Authors
Julie M. Donnelly-Nolan, Marvin A. Lanphere
Locations and descriptions of gravity, box, and push cores collected in San Francisco Bay between January and February, 1990 and 1991 Locations and descriptions of gravity, box, and push cores collected in San Francisco Bay between January and February, 1990 and 1991
A project to study San Francisco Bay sediments collected over 300 sediment gravity cores; six push cores, and three box cores in San Francisco Bay during the years 1990-91. The purpose of the sampling effort is to establish a database on the Holocene sediment history of the bay. The samples described and mapped are the first effort to catalog and present the data collected. Thus far the...
Authors
Roberto J. Anima, H. Edward Clifton, Carol Reiss, Florence L. Wong