Publications
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Argon geochronology of late Pleistocene to Holocene Westdahl volcano, Unimak Island, Alaska Argon geochronology of late Pleistocene to Holocene Westdahl volcano, Unimak Island, Alaska
High-precision 40Ar/39Ar geochronology of selected lavas from Westdahl Volcano places time constraints on several key prehistoric eruptive phases of this large active volcano. A dike cutting old pyroclastic-flow and associated lahar deposits from a precursor volcano yields an age of 1,654+/-11 k.y., dating this precursor volcano as older than early Pleistocene. A total of 11...
Authors
Andrew T. Calvert, Richard B. Moore, Robert G. McGimsey
2003 volcanic activity in Alaska and Kamchatka: Summary of events and response of the Alaska Volcano Observatory 2003 volcanic activity in Alaska and Kamchatka: Summary of events and response of the Alaska Volcano Observatory
The Alaska Volcano Observatory (AVO) monitors the more than 40 historically active volcanoes of the Aleutian Arc. Of these, 24 were considered monitored in real time with short-period seismic instrument networks as of the end of 2003. The AVO core monitoring program also includes daily analysis of satellite imagery, observation over flights, and compilation of pilot reports and reports...
Authors
Robert G. McGimsey, Christina A. Neal, Olga Girina
Landslide hazards: A national threat Landslide hazards: A national threat
Landslides occur and can cause damage in all 50 States. Severe storms, earthquakes, volcanic activity, coastal wave attack, and wildfires can cause widespread slope instability. Landslide danger may be high even as emergency personnel are providing rescue and recovery services. To address landslide hazards, several questions must be considered: Where and when will landslides occur? How...
Authors
Water Resources Division U.S. Geological Survey
InSAR studies of Alaska volcanoes InSAR studies of Alaska volcanoes
Interferometric synthetic aperture radar (InSAR) is a remote sensing technique capable of measuring ground surface deformation with sub-centimeter precision and spatial resolution in tens-ofmeters over a large region. This paper describes basics of InSAR and highlights our studies of Alaskan volcanoes with InSAR images acquired from European ERS-l and ERS-2, Canadian Radarsat-l, and...
Authors
Zhong Lu, Chuck Wicks, Daniel Dzurisin, John A. Power
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
Rainfall-induced landslides in Puerto Rico: An overview Rainfall-induced landslides in Puerto Rico: An overview
Rainfall-induced landslides are common in Puerto Rico (PR). The presence of steep slopes in mountainous terrain, coupled with weathered soils and intense rainfall, leads to severe slope-stability problems throughout the island. Episodic triggering events such as hurricanes and earthquakes further exacerbate these problems. All physiographic provinces of the island have experienced...
Authors
M.A. Pando, M.E. Ruiz, M. C. Larsen
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
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
Water alteration of rocks and soils on Mars at the Spirit rover site in Gusev crater Water alteration of rocks and soils on Mars at the Spirit rover site in Gusev crater
Gusev crater was selected as the landing site for the Spirit rover because of the possibility that it once held a lake. Thus one of the rover's tasks was to search for evidence of lake sediments. However, the plains at the landing site were found to be covered by a regolith composed of olivine-rich basaltic rock and wind-blown 'global' dust. The analyses of three rock interiors exposed...
Authors
L.A. Haskin, A. Wang, B.L. Jolliff, H.Y. McSween, B. C. Clark, D.J. Des Marais, S. M. McLennan, N.J. Tosca, J.A. Hurowitz, J.D. Farmer, A. Yen, S. W. Squyres, R. E. Arvidson, G. Klingelhofer, C. Schroder, P.A. De Souza, D. W. Ming, Ralf Gellert, J. Zipfel, J. Bruckner, J.F. Bell, Kenneth E. Herkenhoff, P. R. Christensen, S. Ruff, D. Blaney, S. Gorevan, N.A. Cabrol, L. Crumpler, J. Grant, L. Soderblom
Pitted cones and domes on Mars: Observations in Acidalia Planitia and Cydonia Mensae using MOC, THEMIS, and TES data Pitted cones and domes on Mars: Observations in Acidalia Planitia and Cydonia Mensae using MOC, THEMIS, and TES data
Domes and cones with summit pits located in Acidalia Planitia and Cydonia Mensae were studied using MOC and THEMIS images and a TES‐derived thermal inertia map. North of 40.5°N latitude, the features have a dome‐like morphology, and south of that latitude, the morphology is more cone‐like. Layering is apparent in the summit craters of fresher looking southern cones, and asymmetric aprons...
Authors
William H. Farrand, Lisa R. Gaddis, Laszlo P. Keszthelyi
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
Hazard calculations for the WGCEP-2002 earthquake forecast using OpenSHA and distributed object technologies Hazard calculations for the WGCEP-2002 earthquake forecast using OpenSHA and distributed object technologies
We present seismic-hazard calculations for what is arguably the most sophisticated earthquake forecast ever developed—the model by the 2002 Working Group on California Earthquake Probabilities (2003), or WGCEP-2002 as referred to hereafter. These calculations have been made possible by developments in both OpenSHA (Field et al., 2003) and the Information Technology Research (ITR)...
Authors
Edward H. Field, N. Gupta, Vipin Gupta, Michael L. Blanpied, Phillip J. Maechling, Thomas H. Jordan