Publications
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Seismicity rate change at the Coso Geothermal Field following the July 2019 Ridgecrest M7.1 earthquake
Many geothermal and volcanic regions experience remote and regional triggering following large earthquakes. The transient or permanent changes in stresses acting on faults and fractures can lead to changes in seismicity rates following either the passage of teleseismic waves or the permanent change in stresses following regional events. One such region of prevalent triggering is the Coso Geotherma
Authors
Joern Kaven
Real-time performance of the PLUM earthquake early warning method during the 2019 M6.4 and M7.1 Ridgecrest, California, Earthquakes
We evaluate the timeliness and accuracy of ground‐motion‐based earthquake early warning (EEW) during the July 2019 M6.4 and 7.1 Ridgecrest earthquakes. In 2018, we began retrospective and internal real‐time testing of the propagation of local undamped motion (PLUM) method for earthquake warning in California, Oregon, and Washington, with the potential that PLUM might one day be included in the Sha
Authors
Sarah E. Minson, Jessie Kate Saunders, Julian Bunn, Elizabeth S. Cochran, Annemarie S. Baltay, Deborah L. Kilb, Mitsuyuki Hoshiba, Yuki Kodera
When source and path components trade off in ground-motion prediction equations
Current research on ground‐motion models (also known as ground‐motion prediction equations [GMPEs]) and their uncertainties focus on the separate contributions of source, path, and site to both median values and their variability. Implicit here is the assumption that the event term, path term, and site term reflect only properties of the source, path, and site, respectively. Events with larger str
Authors
Annemarie S. Baltay, Lauren S. Abrahams, Thomas C. Hanks
Minimal clustering of injection-induced earthquakes observed with a large-n seismic array
The clustering behavior of injection‐induced earthquakes is examined using one month of data recorded by the LArge‐n Seismic Survey in Oklahoma (LASSO) array. The 1829‐node seismic array was deployed in a 25 km×32 km area of active saltwater disposal in northern Oklahoma between 14 April and 10 May 2016. Injection rates in the study area are nearly constant around the time of the deployment. We
Authors
Elizabeth S. Cochran, A. Wickham-Piotrowski, K. Kemna, R. M Harrington, S. Dougherty, A. Pena Castro
Peak ground velocity spatial variability revealed by dense seismic array in southern California
Understanding and modeling variability of ground motion is essential for building accurate and precise ground motion prediction equations, which can net site‐specific characterization and reduced hazard levels. Here, we explore the spatial variability in peak ground velocity (PGV) at Sage Brush Flats along the San Jacinto Fault in southern California. We use data from a dense array (0.6 x 0.6 km2,
Authors
Christopher E Johnson, Debi Kilb, Annemarie S. Baltay, Frank Vernon
Late Quaternary slip rates on the Sierra Madre fault zone and paleoseismic evidence on the size and frequency of past ruptures
The Sierra Madre fault zone is a south-vergent, active reverse fault that accommodates shortening between basins on the northern margin of the Los Angeles region and the San Gabriel Mountains. The preservation of late Quaternary alluvial fill and fan surfaces in the hanging wall of the fault provides evidence of long-term uplift. Surface rupture from the 1971 Mw 6.6 San Fernando earthquake and evi
Authors
Reed J. Burgette, Katherine Scharer, Scott Lindvall
Abundant spontaneous and dynamically triggered submarine landslides in the Gulf of Mexico
Submarine landslides that occur offshore are common along the U.S. continental margins. These mass wasting events can trigger tsunamis and hence potentially devastate coastal communities and damage offshore infrastructure. However, the initiation and failure processes of submarine landslides are poorly understood. Here, we identify and locate 85 previously unknown submarine landslides in the Gulf
Authors
Wenyuan Fan, Jeffrey McGuire, Peter M. Shearer
Active steady-state creep on a nontectonic normal fault in southeast Utah: Implications for strain release in a rapidly deforming salt system
Characterizing short-term temporal variations of fault creep provides insight into the evolution, mechanics, and strength of fault systems. Using spirit leveling and an extensome- ter, we measured surface displacement of a fault southwest of the Needles District, Canyon- lands National Park, Utah, where extension is driven by differential unloading of a subsur- face salt layer due to incision of t
Authors
Katherine Kravitz, Karl Mueller, Roger Bilham, Maureen A. L. Walton
Ground failure triggered by shaking during the November 30, 2018, magnitude 7.1 Anchorage, Alaska, earthquake
We developed an initial inventory of ground failure features from the November 30, 2018, magnitude 7.1 Anchorage earthquake. This inventory of 153 features is from ground-based observations soon after the earthquake (December 5–10) that include the presence or absence of liquefaction, landslides, and individual crack traces of lateral spreads and incipient landslides. This is not a complete invent
Authors
Alex R. R. Grant, Randall W. Jibson, Robert C. Witter, Kate E. Allstadt, Eric M. Thompson, Adrian M. Bender
Aseismic transient slip on the Gofar transform fault, East Pacific Rise
Oceanic transform faults display a unique combination of seismic and aseismic slip behavior, including a large globally averaged seismic deficit, and the local occurrence of repeating magnitude (M) ∼6∼6 earthquakes with abundant foreshocks and seismic swarms, as on the Gofar transform of the East Pacific Rise and the Blanco Ridge in the northeast Pacific Ocean. However, the underlying mechanisms t
Authors
Yajing Liu, Jeffrey McGuire, Mark Behn
2018 U.S. Geological Survey–California Geological Survey fault-imaging surveys across the Hollywood and Santa Monica Faults, Los Angeles County, California
We acquired multiple types of seismic data across the Hollywood Fault in Hollywood, Calif., and the Santa Monica Fault in Beverly Hills, Calif., in May and June 2018. On the basis of our data, we infer near-surface locations of various traces of these faults.From two separate profiles across the Hollywood Fault, we evaluated multiple seismic datasets and models, including guided-wave data, tomogra
Authors
Rufus D. Catchings, Janis Hernandez, Mark R. Goldman, Joanne H. Chan, Robert R. Sickler, Brian Olson, Coyn J. Criley
Coseismic and post-seismic gravity disturbance induced by seismic sources using a 2.5-D spectral element method
I present a prescription for computing free-air coseismic and post-seismic gravity changes induced by seismic sources in a viscoelastic earth model. I assume a spherical earth geometry and a 2.5-D calculation, that is, 3-D motions that satisfy the equations of quasi-static equilibrium on a 2-D viscoelastic structure. The prescription permits application to regional gravity computations where a 2-D
Authors
Fred Pollitz