Publications
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The importance of particulate texture to the flow strength of ice + dust
Preliminary experimental surveys of the flow of dilute mixtures of ice plus hard particulates under planetary conditions indicate a strengthening effect with respect to pure ice, but with dependencies on environmental conditions (temperature, stress, grain size) that vary widely from study to study [1-4]. With the expectation that the textural character of the particulate fraction (size, shape, sp
Authors
W. B. Durham, N. Golding, Laura A. Stern, A. Pathare, D. L. Goldsby, D. Prior
Chemical variations in Yellowknife Bay formation sedimentary rocks analyzed by ChemCam on board the Curiosity rover on Mars
The Yellowknife Bay formation represents a ~5 m thick stratigraphic section of lithified fluvial and lacustrine sediments analyzed by the Curiosity rover in Gale crater, Mars. Previous works have mainly focused on the mudstones that were drilled by the rover at two locations. The present study focuses on the sedimentary rocks stratigraphically above the mudstones by studying their chemical variati
Authors
Nicolas Mangold, Olivier Forni, G. Dromart, K.M. Stack, Roger C. Wiens, Olivier Gasnault, Dawn Y. Sumner, Marion Nachon, Pierre-Yves Meslin, Ryan B. Anderson, Bruce Barraclough, J.F. Bell, G. Berger, D.L. Blaney, J.C. Bridges, F. Calef, Brian R. Clark, Samuel M. Clegg, Agnès Cousin, L. Edgar, Kenneth S. Edgett, B.L. Ehlmann, Cecile Fabre, M. Fisk, John P. Grotzinger, S.C. Gupta, Kenneth E. Herkenhoff, J.A. Hurowitz, J. R. Johnson, Linda C. Kah, Nina L. Lanza, Jeremie Lasue, S. Le Mouélic, Eric Lewin, Michael Malin, Scott M. McLennan, S. Maurice, Noureddine Melikechi, Alissa Mezzacappa, Ralph E. Milliken, H.L. Newsome, A. Ollila, Scott K. Rowland, Violaine Sautter, M.E. Schmidt, S. Schroder, C. D'Uston, Dave Vaniman, R. A. Williams
UCERF3: A new earthquake forecast for California's complex fault system
With innovations, fresh data, and lessons learned from recent earthquakes, scientists have developed a new earthquake forecast model for California, a region under constant threat from potentially damaging events. The new model, referred to as the third Uniform California Earthquake Rupture Forecast, or "UCERF" (http://www.WGCEP.org/UCERF3), provides authoritative estimates of the magnitude, locat
Authors
Edward H. Field
The Mw6.0 24 August 2014 South Napa earthquake
The Mw 6.0 South Napa earthquake, which occurred at 10:20 UTC 24 August 2014 was the largest earthquake to strike the greater San Francisco Bay area since the Mw 6.9 1989 Loma Prieta earthquake. The rupture from this right‐lateral earthquake propagated mostly unilaterally to the north and up‐dip, directing the strongest shaking toward the city of Napa, where peak ground accelerations (PGAs) betwee
Authors
Thomas M. Brocher, Annemarie S. Baltay, Jeanne L. Hardebeck, Fred F. Pollitz, Jessica R. Murray, Andrea L. Llenos, David P. Schwartz, J. Luke Blair, Daniel J. Ponti, James J. Lienkaemper, Victoria E. Langenheim, Timothy E. Dawson, Kenneth W. Hudnut, David R. Shelly, Douglas S. Dreger, John Boatwright, Brad T. Aagaard, David J. Wald, Richard M. Allen, William D. Barnhart, Keith L. Knudsen, Benjamin A. Brooks, Katherine M. Scharer
The comparative limnology of Lakes Nyos and Monoun, Cameroon
Lakes Nyos and Monoun are known for the dangerous accumulation of CO2 dissolved in stagnant bottom water, but the shallow waters that conceal this hazard are dilute and undergo seasonal changes similar to other deep crater lakes in the tropics. Here we discuss these changes with reference to climatic and water-column data collected at both lakes during the years following the gas release disasters
Authors
George Kling, William C Evans, Gregory Tanyileke
Strain accumulation across the Prince William Sound asperity, Southcentral Alaska
The surface velocities predicted by the conventional subduction model are compared to velocities measured in a GPS array (surveyed in 1993, 1995, 1997, 2000, and 2004) spanning the Prince William Sound asperity. The observed velocities in the comparison have been corrected to remove the contributions from postseismic (1964 Alaska earthquake) mantle relaxation. Except at the most seaward monument (
Authors
James C. Savage, Jerry L. Svarc, Michael Lisowski
The data quality analyzer: a quality control program for seismic data
The U.S. Geological Survey's Albuquerque Seismological Laboratory (ASL) has several initiatives underway to enhance and track the quality of data produced from ASL seismic stations and to improve communication about data problems to the user community. The Data Quality Analyzer (DQA) is one such development and is designed to characterize seismic station data quality in a quantitative and automate
Authors
Adam T. Ringler, M.T. Hagerty, James F. Holland, A. Gonzales, Lind S. Gee, J.D. Edwards, David C. Wilson, Adam Baker
Quaternary tephrochronology and deposition in the subsurface Sacramento–San Joaquin Delta, California, U.S.A.
We document characteristics of tephra, including facies and geochemistry, from 27 subsurface sites in the Sacramento-San Joaquin Delta, California, to obtain stratigraphic constraints in a complex setting. Analyzed discrete tephra deposits are correlative with: 1) an unnamed tephra from the Carlotta Formation near Ferndale, California, herein informally named the ash of Wildcat Grade (<~1.450 - >~
Authors
Katherine L. Maier, Emma Gatti, Elmira Wan, Daniel J. Ponti, Mark Pagenkopp, Scott W. Starratt, Holly A. Olson, John Tinsley
Long‐term time‐dependent probabilities for the third Uniform California Earthquake Rupture Forecast (UCERF3)
The 2014 Working Group on California Earthquake Probabilities (WGCEP 2014) presents time-dependent earthquake probabilities for the third Uniform California Earthquake Rupture Forecast (UCERF3). Building on the UCERF3 time-independent model, published previously, renewal models are utilized to represent elastic-rebound-implied probabilities. A new methodology has been developed that solves applica
Authors
Edward H. Field, Glenn P. Biasi, Peter Bird, Timothy E. Dawson, Karen R. Felzer, David A. Jackson, Kaj M. Johnson, Thomas H. Jordan, Christopher Madden, Andrew J. Michael, Kevin Milner, Morgan T. Page, Thomas E. Parsons, Peter Powers, Bruce E. Shaw, Wayne R. Thatcher, Ray J. Weldon, Yuehua Zeng
Mars Reconnaissance Orbiter and Opportunity observations of the Burns formation: crater hopping at Meridiani Planum
Compact Reconnaissance Imaging Spectrometer for Mars hyperspectral (1.0–2.65 µm) along-track oversampled observations covering Victoria, Santa Maria, Endeavour, and Ada craters were processed to 6 m/pixel and used in combination with Opportunity observations to detect and map hydrated Mg and Ca sulfate minerals in the Burns formation. The strongest spectral absorption features were found to be ass
Authors
R.E. Arvidson, J.F. Bell, J.G. Catalano, B. C. Clark, V.K. Fox, Ralf Gellert, J.P. Grotzinger, E.A. Guinness, Kenneth E. Herkenhoff, A.H. Knoll, M.G.A. Lapotre, S. M. McLennan, D. W. Ming, R.V. Morris, S.L. Murchie, K. E. Powell, M. D. Smith, S. W. Squyres, M.J. Wolff, J.J. Wray
The Red Atrapa Sismos (Quake Catcher Network in Mexico): assessing performance during large and damaging earthquakes.
The Quake‐Catcher Network (QCN) is an expanding seismic array made possible by thousands of participants who volunteered time and resources from their computers to record seismic data using low‐cost accelerometers (http://qcn.stanford.edu/; last accessed December 2014). Sensors based on Micro‐Electromechanical Systems (MEMS) technology have rapidly improved over the last few years due to the deman
Authors
Luis A. Dominguez, Battalgazi Yildirim, Allen L. Husker, Elizabeth S. Cochran, Carl Christensen, Victor M. Cruz-Atienza
Revisions to some parameters used in stochastic-method simulations of ground motion
The stochastic method of ground‐motion simulation specifies the amplitude spectrum as a function of magnitude (M) and distance (R). The manner in which the amplitude spectrum varies with M and R depends on physical‐based parameters that are often constrained by recorded motions for a particular region (e.g., stress parameter, geometrical spreading, quality factor, and crustal amplifications), whic
Authors
David Boore, Eric M. Thompson