Publications
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Shallow faulting and folding in the epicentral area of the 1886 Charleston, South Carolina, earthquake Shallow faulting and folding in the epicentral area of the 1886 Charleston, South Carolina, earthquake
The moment magnitude (Mw�w) ∼7 earthquake that struck Charleston, South Carolina, on 31 August 1886 is the largest historical earthquake in the United States east of the Appalachian Mountains. The fault(s) that ruptured during this earthquake has never been conclusively identified, and conflicting fault models have been proposed. Here we interpret reprocessed seismic reflection...
Authors
Thomas L. Pratt, Anjana K. Shah, R.C Counts, J. Wright Horton,, M.C. Chapman
Rainfall triggering of post-fire debris flows over a 28-year period near El Portal, California, USA Rainfall triggering of post-fire debris flows over a 28-year period near El Portal, California, USA
Wildfires frequently affect the steep hillslopes near El Portal, California (United States), a small community established during the California Gold Rush in the mid-1800s. In addition to the historical significance of El Portal, State Route 140 (SR 140) is a major transportation and economic corridor connecting the San Joaquin Valley to Yosemite National Park (YNP). In 2019, an...
Authors
Jerome V. De Graff, Dennis M. Staley, Greg M. Stock, Kellen Takenaka, Alan L. Gallegos, Chad K. Neptune
Partitioning ground motion uncertainty when conditioned on station data Partitioning ground motion uncertainty when conditioned on station data
Rapid estimation of earthquake ground shaking and proper accounting of associated uncertainties in such estimates when conditioned on strong‐motion station data or macroseismic intensity observations are crucial for downstream applications such as ground failure and loss estimation. The U.S. Geological Survey ShakeMap system is called upon to fulfill this objective in light of increased...
Authors
Davis T. Engler, Charles Worden, Eric M. Thompson, Kishor S. Jaiswal
How similar was the 1983 Mw 6.9 Borah Peak earthquake rupture to its surface-faulting predecessors along the northern Lost River fault zone (Idaho, USA)? How similar was the 1983 Mw 6.9 Borah Peak earthquake rupture to its surface-faulting predecessors along the northern Lost River fault zone (Idaho, USA)?
We excavated trenches at two paleoseismic sites bounding a trans-basin bedrock ridge (the Willow Creek Hills) along the northern Lost River fault zone to explore the uniqueness of the 1983 Mw 6.9 Borah Peak earthquake compared to its prehistoric predecessors. At the Sheep Creek site on the southernmost Warm Springs section, two earthquakes occurred at 9.8−14.0 ka (95% confidence) and 6.5...
Authors
Christopher B. DuRoss, Richard W. Briggs, Ryan D. Gold, Alexandra Elise Hatem, Austin John Elliott, Jaime Delano, Ivan Medina-Cascales, Harrison J. Gray, Shannon A. Mahan, Sylvia Nicovich, Zachery Lifton, Emily J. Kleber, Greg N. McDonald, Adam Hiscock, Mike Bunds, Nadine G. Reitman
Ground failure triggered by the 7 January 2020 M6.4 Puerto Rico earthquake Ground failure triggered by the 7 January 2020 M6.4 Puerto Rico earthquake
The 7 January 2020 M 6.4 Puerto Rico earthquake, the mainshock of an extended earthquake sequence, triggered significant ground failure. In this study, we detail the ground failure that occurred based largely on a postearthquake field reconnaissance campaign that we conducted. We documented more than 300 landslides, mainly rock falls that were concentrated in areas where peak ground...
Authors
Kate E. Allstadt, Eric M. Thompson, Desiree Bayouth Garcia, Edwin Irizarry Brugman, K. Stephen Hughes, Robert G. Schmitt
Ready for real time: Performance of Global Navigation Satellite System in 2019 Mw 7.1 Ridgecrest, California, rapid response products Ready for real time: Performance of Global Navigation Satellite System in 2019 Mw 7.1 Ridgecrest, California, rapid response products
Global Navigation Satellite Systems (GNSSs) have undergone notable advancement in the last few decades, leading to the availability of a dataset with capabilities well beyond its original intended purpose. The proliferation of high‐rate (1 Hz or greater) GNSS receivers in areas of seismological interest now allows for routine consideration of dynamic earthquake ground motions, with...
Authors
Dara Elyse Goldberg, Kirstie Lafon Haynie
Seismic background noise levels across the continental United States from USArray Transportable Array: The influence of geology and geography Seismic background noise levels across the continental United States from USArray Transportable Array: The influence of geology and geography
Since 2004, the most complete estimate of background noise levels across the continental U.S. was attained using 61 broadband seismic stations to calculate power spectral density (PSD) probability density functions. To improve seismic noise estimates across the U.S., we examine vertical component seismic data from the EarthScope USArray Transportable Array seismic network that rolled...
Authors
Robert E. Anthony, Adam T. Ringler, David C. Wilson
Portable optically stimulated luminescence age map of a paleoseismic exposure Portable optically stimulated luminescence age map of a paleoseismic exposure
The quality and quantity of geochronologic data used to constrain the history of major earthquakes in a region exerts a first-order control on the accuracy of seismic hazard assessments that affect millions of people. However, evaluations of geochronological data are limited by uncertainties related to inherently complex depositional processes that may vary spatially and temporally. To...
Authors
Christopher B. DuRoss, Ryan D. Gold, Harrison J. Gray, Sylvia R. Nicovich
Open-source resources help navigate new IM regulations Open-source resources help navigate new IM regulations
The revision of federal safety regulations for integrity management of gas transmission pipelines to require explicit consideration of seismicity increases the importance for operators to be actively identifying high-consequence areas (HCAs), evaluating seismic-related threats, and choosing a risk model to support risk management decisions. To ensure equal access to information by both...
Authors
N. Simon Kwong, Kishor S. Jaiswal, J. W. Baker, Nico Luco, K. A. Ludwig, Vasey J. Stephens
Seismic site characterization with shear wave (SH) reflection and refraction methods Seismic site characterization with shear wave (SH) reflection and refraction methods
Reflection and critically refracted seismic methods use traveltime measurements of body waves propagating between a source and a series of receivers on the ground surface to calculate subsurface velocities. Body wave energy is refracted or reflected at boundaries where there is a change in seismic impedance, defined as the product of material density and seismic velocity. This article...
Authors
James A. Hunter, Heather L. Crow, William J. Stephenson, Andre J.-M. Pugin, Robert Williams, James B. Harris, Jackson K. Odum, Edward W Woolery
An assessment of uncertainties in VS profiles obtained from microtremor observations in the phased 2018 COSMOS blind trials An assessment of uncertainties in VS profiles obtained from microtremor observations in the phased 2018 COSMOS blind trials
Site response is a critical consideration when assessing earthquake hazards. Site characterization is key to understanding site effects as influenced by seismic site conditions of the local geology. Thus, a number of geophysical site characterization methods were developed to meet the demand for accurate and cost-effective results. As a consequence, a number of studies have been...
Authors
Michael W. Asten, Alan Yong, Sebastiano Foti, Koichi Hayashi, Antony J. Martin, William J. Stephenson, John F. Cassidy, Jacie Coleman, Robert L. Nigbor, Silvia Castellaro, Kosuke Chimoto, Ikuo Cho, Cecile Cornou, Takumi Hayashida, Manuel Hobiger, Chun-Hsiang Kuo, Albert Macau, E. Diego Mercerat, Sheri Molnar, Passakorn Pananont, Marco Pilz, Nakhorn Poovarodom, Esteban Saez, Marc Wathelet, Hiroaki Yamanaka, Toshiaki Yokoi, Don Zhao
Landslides triggered by the 2002 M 7.9 Denali Fault earthquake, Alaska, USA Landslides triggered by the 2002 M 7.9 Denali Fault earthquake, Alaska, USA
The 2002 M 7.9 Denali earthquake in Alaska, USA, was the largest inland earthquake in North America in nearly 150 years. The earthquake involved oblique thrusting but mostly strike-slip motion, and faults ruptured the ground surface over 330 km. Fault rupture occurred in a rugged, mountainous, subarctic environment with extensive permafrost and variable glaciation, geology, and...
Authors
William H. Schulz