Publications
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A microphysically-based approach to modeling emissivity and albedo of the martian seasonal caps
A new model of albedo and emissivity of the martian seasonal caps represented as porous CO2 slabs containing spherical voids and dust particles is described. In the model, a radiative transfer model is coupled with a microphysical model in order to link changes in albedo and emissivity to changes in porosity caused by ice metamorphism. The coupled model is capable of reproducing temporal changes i
Authors
Janusz Eluszkiewicz, Jean-Luc Moncet, Timothy N. Titus, Gary B. Hansen
Remotely triggered earthquakes following moderate mainshocks (or, why California is not falling into the ocean)
On several occasions in recent memory California has experienced apparent clusters of earthquake activity that are too far apart to be considered related according to a classic taxonomy that includes foreshocks, mainshocks, and aftershocks. During a week-long period in July 1986, California experienced the M 6.0 North Palm Springs earthquake, the M 5.5 Oceanside earthquake, and a swarm of smaller
Authors
Susan E. Hough
Preliminary report on the 28 September 2004, M 6.0 Parkfield, California earthquake
The Mw 6.0 Parkfield earthquake struck central California at 17:15:14 UTC on 28 September 2004. The epicenter was located 11 km southeast of the rural town of Parkfield, adjacent to Gold Hill and on the San Andreas Fault (Figure 1). The California Integrated Seismic Network (CISN) reported that the hypocenter was located at 35.819°N, 120.364°W at a depth of 8.8 km. From the distribution of aftersh
Authors
John Langbein, Roger D. Borcherdt, Douglas Dreger, J. Fletcher, Jeanne L Hardebeck, Margaret Hellweg, C. Ji, Malcolm J. S. Johnston, Jessica R. Murray, Robert Nadeau, Michael J. Rymer, Jerome A. Treiman
Advantageous GOES IR results for ash mapping at high latitudes: Cleveland eruptions 2001
The February 2001 eruption of Cleveland Volcano, Alaska allowed for comparisons of volcanic ash detection using two‐band thermal infrared (10–12 μm) remote sensing from MODIS, AVHRR, and GOES 10. Results show that high latitude GOES volcanic cloud sensing the range of about 50 to 65°N is significantly enhanced. For the Cleveland volcanic clouds the MODIS and AVHRR data have zenith angles 6–65 degr
Authors
Yingxin Gu, William I. Rose, D.J. Schneider, G.J.S. Bluth, I.M. Watson
An alternative approach to characterize nonlinear site effects
This paper examines the rationale of a method of nonstationary processing and analysis, referred to as the Hilbert-Huang transform (HHT), for its application to a recording-based approach in quantifying influences of soil nonlinearity in site response. In particular, this paper first summarizes symptoms of soil nonlinearity shown in earthquake recordings, reviews the Fourier-based approach to char
Authors
R.R. Zhang, S. Hartzell, J. Liang, Y. Hu
Interferometric synthetic aperture radar study of Okmok volcano, Alaska, 1992-2003: Magma supply dynamics and postemplacement lava flow deformation
Okmok volcano, located in the central Aleutian arc, Alaska, is a dominantly basaltic complex topped with a 10-km-wide caldera that formed circa 2.05 ka. Okmok erupted several times during the 20th century, most recently in 1997; eruptions in 1945, 1958, and 1997 produced lava flows within the caldera. We used 80 interferometric synthetic aperture radar (InSAR) images (interferograms) to study tran
Authors
Z. Lu, Timothy Masterlark, Daniel Dzurisin
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 tensions that v
Authors
M. Mangan, T. Sisson
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) Collaboration of
Authors
Edward H. Field, N. Gupta, Vipin Gupta, Michael L. Blanpied, Phillip J. Maechling, Thomas H. Jordan
The ubiquitous nature of accessory calcite in granitoid rocks: Implications for weathering, solute evolution, and petrogenesis
Calcite is frequently cited as a source of excess Ca, Sr and alkalinity in solutes discharging from silicate terrains yet, no previous effort has been made to assess systematically the overall abundance, composition and petrogenesis of accessory calcite in granitoid rocks. This study addresses this issue by analyzing a worldwide distribution of more than 100 granitoid rocks. Calcite is found to be
Authors
A. F. White, M. S. Schulz, J. B. Lowenstern, D.V. Vivit, T.D. Bullen
2004 volcanic activity in Alaska and Kamchatka: Summary of events and response of the Alaska Volcano Observatory
No abstract available.
Authors
Christina A. Neal, Robert G. McGimsey, Jim Dixon, Dmitry Melnikov
An assessment of volcanic threat and monitoring capabilities in the United States: Framework for a National Volcano Early Warning System
Executive SummaryNVEWS – a National Volcano Early Warning System – is being formulated by the Consortium of U.S. Volcano Observatories (CUSVO) to establish a proactive, fully integrated, national-scale monitoring effort that ensures the most threatening volcanoes in the United States are properly monitored in advance of the onset of unrest and at levels commensurate with the threats posed. Volcani
Authors
John W. Ewert, Marianne Guffanti, Thomas L. Murray