Publications
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Late Holocene slip rate of the Mojave section of the San Andreas Fault near Palmdale, California
The geologic slip rate on the Mojave section of the San Andreas fault is poorly constrained, despite its importance for understanding earthquake hazard, apparent discrepancies between geologic and geodetic slip rates along this fault section, and long‐term fault interactions in southern California. Here, we use surficial geologic mapping, excavations, and radiocarbon and luminescence dating to qua
Authors
Elaine Young, Eric Cowgill, Katherine Scharer, Emery Anderson-Merritt, Amanda Keen-Zebert, Ray J. Weldon
Electrical properties of carbon dioxide hydrate: Implications for monitoring CO2 in the gas hydrate stability zone
CO2 and CH4 clathrate hydrates are of keen interest for energy and carbon cycle considerations. While both typically form on Earth as cubic structure I (sI), we find that pure CO2 hydrate exhibits over an order of magnitude higher electrical conductivity (σ) than pure CH4 hydrate at geologically relevant temperatures. The conductivity was obtained from frequency-dependent impedance (Z) measurement
Authors
Laura A. Stern, S. Constable, Ryan Lu, Wyatt L. Du Frane, J. Murray Roberts
Seismic and geodetic analysis of rupture characteristics of the 2020 Mw 6.5 Monte Cristo Range, Nevada, earthquake
The largest earthquake since 1954 to strike the state of Nevada, United States, ruptured on 15 May 2020 along the Monte Cristo range of west‐central Nevada. The Mw 6.5 event involved predominantly left‐lateral strike‐slip faulting with minor normal components on three aligned east–west‐trending faults that vary in strike by 23°. The kinematic rupture process is determined by joint inversion of Glo
Authors
Chengli Liu, Thorne Lay, Fred Pollitz, Jiao Xu, Xiong Xiong
NGA-East Ground-Motion Characterization model part I: Summary of products and model development
In this article, we present an overview of the research project NGA-East, Next Generation Attenuation for Central and Eastern North America (CENA), and summarize the key methodology and products. The project was tasked with developing a new ground motion characterization (GMC) model for CENA. The final NGA-East GMC model includes a set of 17 median ground motion models (GMMs) for peak ground accel
Authors
Christine A. Goulet, Yousef Bozorgnia, Nicolas Kuehn, Linda Al Atik, Robert Youngs, Robert Graves, Gail M. Atkinson
Selection of random vibration theory procedures for the NGA-East project and ground-motion modeling
Traditional ground-motion models (GMMs) are used to compute pseudo-spectral acceleration (PSA) from future earthquakes and are generally developed by regression of PSA using a physics-based functional form. PSA is a relatively simple metric that correlates well with the response of several engineering systems and is a metric commonly used in engineering evaluations; however, characteristics of the
Authors
Albert R. Kottke, Norman A. Abrahamson, David Boore, Yousef Bozorgina, Christine A. Goulet, Justin Hollenback, Tadahiro Kishida, Olga-Joan Ktenidou, Ellen Rathje, Walt Silva, Eric M. Thompson, Xiaoyue Wang
Wastewater disposal has not significantly altered the regional stress state in southern Kansas
Wastewater disposal is primarily responsible for the increased seismicity rate since ~2013 in southern Kansas. Previous work that used shear wave splitting (SWS) in southern Kansas interpreted a ~90º temporal rotation in the fast polarization direction and attributed it to increased pore pressures resulting from fluid injection. However, this interpreted rotation coincided with a change in the sta
Authors
Robert Skoumal, Elizabeth S. Cochran
Coastal Tree-Ring Records for Paleoclimate and Paleoenvironmental Applications in North America
For more than a century, tree-ring research has identified relationships between climatic and ecological conditions and tree growth to describe past environments and constrain future ecosystem vulnerabilities. Tree-ring records are frequently used as environmental proxies that extend knowledge of past climate and ecology on millennial scales. Many of the most pressing global change questions facin
Authors
Clay Tucker, Jessie K. Pearl
Evaluating spectral ratio methods for characterizing fundamental resonance peaks on flat sediments: An example from the Atlantic Coastal Plain, Eastern United States
Damaging ground motions from the 2011 Mw 5.8 Virginia earthquake were likely increased due to site amplification from the unconsolidated sediments of the Atlantic Coastal Plain (ACP), highlighting the need to understand site response on these widespread strata along the coastal regions of the eastern United States. The horizontal‐to‐vertical spectral ratio (HVSR) method, using either earthquake si
Authors
Lisa Sue Schleicher, Thomas L. Pratt
Earthquake source mechanisms and stress field variations associated with wastewater-induced seismicity in southern Kansas, USA
The strong increase of seismicity rates in the contiguous USA over the last 10 years is linked to the injection of huge amounts of wastewater from oil and gas production in unconventional hydrocarbon reservoirs. We calculated 549 moment tensors of induced earthquakes (MW ≤ 4.9) in southern Kansas to study their source mechanisms and their relation to injection activity. Seventeen percent of the ev
Authors
Amandine Amemotou, Patricia Martinez-Garzon, Grzegorz Kwiatek, Justin Rubinstein, Marco Bohnhoff
Exploring GPS observations of postseismic deformation following the 2012 MW7.8 Haida Gwaii and 2013 MW7.5 Craig, Alaska Earthquakes: Implications for viscoelastic Earth structure
The Queen Charlotte-Fairweather Fault (QC-FF) system off the coast of British Columbia and southeast Alaska is a highly active dextral strike-slip plate boundary that accommodates ∼50 mm/yr of relative motion between the Pacific and North America plates. Nine MW ≥ 6.7 earthquakes have occurred along the QC-FF system since 1910, including a MS(G-R)8.1 event in 1949. Two recent earthquakes, the Octo
Authors
Katherine A. Guns, Fred Pollitz, Thorne Lay, Han Yue
Strength recovery and sealing under hydrothermal conditions
While there is significant evidence for healing in natural faults, geothermal reservoirs, and lab experiments, the thermal, hydraulic, mechanical, and chemical interactions that influence healing are poorly understood. We present preliminary results of triaxial slide-hold-slide experiments to constrain rates and mechanisms of healing. Experiments were conducted on gouge composed of Westerly granit
Authors
Tamara Nicole Jeppson, David A. Lockner, Brian D. Kilgore, Nicholas M. Beeler, Joshua M. Taron
Creep on the Sargent Fault over the past 50 yr from alignment arrays with implications for slip transfer between the Calaveras and San Andreas Faults, California
The 55‐km‐long Sargent fault connects the creeping Calaveras fault with the locked San Andreas fault through the Santa Cruz Mountains west of Gilroy, California. The position of the Sargent fault between these two faults may have implications for slip transfer and strain accumulation between a creeping and locked fault. The detection and measurement of creep on the Sargent fault would indicate whe
Authors
Daniel Mongovin, Belle E. Philibosian