Publications
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Toppling analysis of the Echo Cliffs precariously balanced rock Toppling analysis of the Echo Cliffs precariously balanced rock
Toppling analysis of a precariously balanced rock (PBR) can provide insight into the nature of ground motion that has not occurred at that location in the past and, by extension, can constrain peak ground motions for use in engineering design. Earlier approaches have targeted 2D models of the rock or modeled the rock–pedestal contact using spring‐damper assemblies that require...
Authors
Swetha Veeraraghavan, Kenneth W. Hudnut, Swaminathan Krishnan
Geologic controls on submarine slope failure along the central U.S. Atlantic margin: Insights from the Currituck Slide Complex Geologic controls on submarine slope failure along the central U.S. Atlantic margin: Insights from the Currituck Slide Complex
Multiple styles of failure, ranging from densely spaced, mass transport driven canyons to the large, slab-type slope failure of the Currituck Slide, characterize adjacent sections of the central U.S. Atlantic margin that appear to be defined by variations in geologic framework. Here we use regionally extensive, deep penetration multichannel seismic (MCS) profiles to reconstruct the...
Authors
Jenna C. Hill, Daniel S. Brothers, Bradley K. Craig, Uri S. ten Brink, Jason D. Chaytor, Claudia Flores
Solving for source parameters using nested array data: A case study from the Canterbury, New Zealand earthquake sequence Solving for source parameters using nested array data: A case study from the Canterbury, New Zealand earthquake sequence
The seismic spectrum can be constructed by assuming a Brune spectral model and estimating the parameters of seismic moment (M0), corner frequency (fc), and high-frequency site attenuation (κ). Using seismic data collected during the 2010–2011 Canterbury, New Zealand, earthquake sequence, we apply the non-linear least-squares Gauss–Newton method, a deterministic downhill optimization...
Authors
Corrie Neighbors, Elizabeth S. Cochran, Kenneth Ryan, Anna E. Kaiser
Evidence for coseismic subsidence events in a southern California coastal saltmarsh Evidence for coseismic subsidence events in a southern California coastal saltmarsh
Paleoenvironmental records from a southern California coastal saltmarsh reveal evidence for repeated late Holocene coseismic subsidence events. Field analysis of sediment gouge cores established discrete lithostratigraphic units extend across the wetland. Detailed sediment analyses reveal abrupt changes in lithology, percent total organic matter, grain size, and magnetic susceptibility
Authors
Robert Leeper, Brady P. Rhodes, Matthew E. Kirby, Katherine M. Scharer, Joseph A. Carlin, Eileen Hemphill-Haley, Simona Avnaim-Katav, Glen M. MacDonald, Scott W. Starratt, Angela Aranda
Large earthquakes and creeping faults Large earthquakes and creeping faults
Faults are ubiquitous throughout the Earth's crust. The majority are silent for decades to centuries, until they suddenly rupture and produce earthquakes. With a focus on shallow continental active-tectonic regions, this paper reviews a subset of faults that have a different behavior. These unusual faults slowly creep for long periods of time and produce many small earthquakes. The...
Authors
Ruth A. Harris
Ground-rupturing earthquakes on the northern Big Bend of the San Andreas Fault, California, 800 A.D. to Present Ground-rupturing earthquakes on the northern Big Bend of the San Andreas Fault, California, 800 A.D. to Present
Paleoseismic data on the timing of ground-rupturing earthquakes constrain the recurrence behavior of active faults and can provide insight on the rupture history of a fault if earthquakes dated at neighboring sites overlap in age and are considered correlative. This study presents the evidence and ages for 11 earthquakes that occurred along the Big Bend section of the southern San...
Authors
Katherine M. Scharer, Ray J. Weldon, Glenn Biasi, Ashley Streig, Thomas E. Fumal
CO2 diffusion into pore spaces limits weathering rate of an experimental basalt landscape CO2 diffusion into pore spaces limits weathering rate of an experimental basalt landscape
Basalt weathering is a key control over the global carbon cycle, though in situ measurements of carbon cycling are lacking. In an experimental, vegetation-free hillslope containing 330 m3 of ground basalt scoria, we measured real-time inorganic carbon dynamics within the porous media and seepage flow. The hillslope carbon flux (0.6–5.1 mg C m–2 h–1) matched weathering rates of natural...
Authors
Joost van Haren, Katerina Dontsova, Greg A. Barron-Gafford, Peter A. Troch, Jon Chorover, Stephen B. DeLong, David D. Breshears, Travis E. Huxman, Jon D. Pelletier, Scott Saleska, Xubin Zeng, Joaquin Ruiz
Subsurface volatile content of martian double-layer ejecta (DLE) craters Subsurface volatile content of martian double-layer ejecta (DLE) craters
Excess ice is widespread throughout the martian mid-latitudes, particularly in Arcadia Planitia, where double-layer ejecta (DLE) craters also tend to be abundant. In this region, we observe the presence of thermokarstically-expanded secondary craters that likely form from impacts that destabilize a subsurface layer of excess ice, which subsequently sublimates. The presence of these...
Authors
Donna Viola, Alfred S. McEwen, Colin M. Dundas, Shane Byrne
Broadband seismic noise attenuation versus depth at the Albuquerque Seismological Laboratory Broadband seismic noise attenuation versus depth at the Albuquerque Seismological Laboratory
Seismic noise induced by atmospheric processes such as wind and pressure changes can be a major contributor to the background noise observed in many seismograph stations, especially those installed at or near the surface. Cultural noise such as vehicle traffic or nearby buildings with air handling equipment also contributes to seismic background noise. Such noise sources fundamentally...
Authors
Charles R. Hutt, Adam T. Ringler, Lind Gee
Recalibration of the Mars Science Laboratory ChemCam instrument with an expanded geochemical database Recalibration of the Mars Science Laboratory ChemCam instrument with an expanded geochemical database
The ChemCam Laser-Induced Breakdown Spectroscopy (LIBS) instrument onboard the Mars Science Laboratory (MSL) rover Curiosity has obtained > 300,000 spectra of rock and soil analysis targets since landing at Gale Crater in 2012, and the spectra represent perhaps the largest publicly-available LIBS datasets. The compositions of the major elements, reported as oxides (SiO2, TiO2, Al2O3...
Authors
Samuel M. Clegg, Roger C. Wiens, Ryan B. Anderson, Olivier Forni, Jens Frydenvang, Jeremie Lasue, Agnes Cousin, Valerie Payre, Tommy Boucher, M. Darby Dyar, Scott M. McLennan, Richard V. Morris, Trevor G. Graff, Stanley A Mertzman, Bethany L. Ehlmann, Ines Belgacem, Horton E. Newsom, Ben C. Clark, Noureddine Melikechi, Alissa Mezzacappa, Rhonda E. McInroy, Ronald Martinez, Patrick J. Gasda, Olivier Gasnault, Sylvestre Maurice
Unusual geologic evidence of coeval seismic shaking and tsunamis shows variability in earthquake size and recurrence in the area of the giant 1960 Chile earthquake Unusual geologic evidence of coeval seismic shaking and tsunamis shows variability in earthquake size and recurrence in the area of the giant 1960 Chile earthquake
An uncommon coastal sedimentary record combines evidence for seismic shaking and coincident tsunami inundation since AD 1000 in the region of the largest earthquake recorded instrumentally: the giant 1960 southern Chile earthquake (Mw 9.5). The record reveals significant variability in the size and recurrence of megathrust earthquakes and ensuing tsunamis along this part of the Nazca...
Authors
M. Cisternas, E Garrett, Robert L. Wesson, T. Dura, L. L Ely
Systematic comparisons between PRISM version 1.0.0, BAP, and CSMIP ground-motion processing Systematic comparisons between PRISM version 1.0.0, BAP, and CSMIP ground-motion processing
A series of benchmark tests was run by comparing results of the Processing and Review Interface for Strong Motion data (PRISM) software version 1.0.0 to Basic Strong-Motion Accelerogram Processing Software (BAP; Converse and Brady, 1992), and to California Strong Motion Instrumentation Program (CSMIP) processing (Shakal and others, 2003, 2004). These tests were performed by using the...
Authors
Erol Kalkan, Christopher Stephens