Publications
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Testing the ShakeAlert earthquake early warning system using synthesized earthquake sequences
We test the behavior of the United States (US) West Coast ShakeAlert earthquake early warning (EEW) system during temporally close earthquake pairs to understand current performance and limitations. We consider performance metrics based on source parameter and ground‐motion forecast accuracy, as well as on alerting timeliness. We generate ground‐motion times series for synthesized earthquake seque
Authors
Maren Böse, Jennifer Andrews, Colin T O'Rourke, Deborah L. Kilb, Angela Lux, Julian Bunn, Jeffrey McGuire
Spatially continuous models of aleatory variability in seismic site response for southern California
We develop an empirical, spatially continuous model for the single-station within-event (ϕSS) component of earthquake ground motion variability in the Los Angeles area. ϕSS represents event-to-event variability in site response or remaining variability due to path effects not captured by ground motion models. Site-specific values of ϕSS at permanent seismic network stations were estimated during o
Authors
Grace Alexandra Parker, Annemarie S. Baltay, Eric M. Thompson
Performance of NGA-East GMMs and site amplification models relative to CENA ground motions
We investigate bias in ground motions predicted for Central and Eastern North America (CENA) using ground motion models (GMMs) combined with site amplification models developed in the NGA-East project. Bias is anticipated because of de-coupled procedures used in the development of the GMMs and site amplification models. The NGA-East GMMs were mainly calibrated by adjusting CENA data to a reference
Authors
Maria E. Ramos-Sepulveda, Grace Alexandra Parker, Meibai Li, Okan Ilhan, Youssef M. A. Hashash, Ellen Rathje, Jonathan P. Stewart
Estimates of kappa in the San Francisco Bay area
Site characterization is a critical component of seismic hazards studies, especially in the development and use of ground motion models (GMMs). One such parameter, kappa (Κ0), represents local site attenuation and effectively describes regional variations in ground motion [1]. However, estimates of Κ0 are limited. We estimate the site parameter Κ0 for 296 broadband and accelerometer stations in th
Authors
Tara A. Nye, Valerie J. Sahakian, E.L. King, Annemarie S. Baltay, Alexis Klimasewski
Earthquake early warning: Toward modeling optimal protective actions
Over the past few years early earthquake warning systems have been incorporated into earthquake preparation efforts in many locations around the globe. These systems provide an excellent opportunity for advanced warning of ground shaking and other hazards associated with earthquakes. This study aims to optimize this advanced warning for individuals inside a building when the alert is received. A c
Authors
M. Wood, X. Zhang, X. Zhao, Sara McBride, Nicolas Luco, D. Baldwin, T. Covas
2018 M7.1 Anchorage and 2021 M7.2 Nippes, Haiti earthquake case studies for Virtual Earthquake Reconnaissance Team (VERT) activation protocols, policies, and procedures to gather earthquake response footage
The collection of online videos and imagery to use in disaster reconnaissance is increasing in frequency, due to accessibility of platforms and the ubiquitous nature of smartphones and recording devices. In this short article, we explore the processes, goals, and utility of Virtual Emergency Reconnaissance Teams (VERTs) to collect footage and imagery of geohazards (earthquakes, volcanoes, tsunamis
Authors
Sara McBride, J. Bellizzi, S. Gin, G. Henry, D. F. Sumy, D. Baldwin, E. Fischer
Update on the Center for Engineering Strong-Motion Data (CESMD)
he Center for Engineering Strong-Motion Data (CESMD), an internationally utilized joint center of the U.S. Geological Survey (USGS) and the California Geological Survey (CGS), provides a unified access point for earthquake strong-motion records and station metadata from the CGS California Strong-Motion Instrumentation Program (CSMIP), the USGS National Strong-Motion Project (NSMP), the USGS Advanc
Authors
L. Hagos, H. Haddadi, Lisa Sue Schleicher, Jamison Haase Steidl, Lind Gee, M. Dhar
Western U.S. deformation models for the 2023 update to the U.S. National Seismic Hazard Model
This report describes geodetic and geologic information used to constrain deformation models of the 2023 update to the National Seismic Hazard Model (NSHM), a set of deformation models to interpret these data, and their implications for earthquake rates in the western United States. Recent updates provide a much larger data set of Global Positioning System crustal velocities than used in the 2014
Authors
Fred Pollitz, Eileen L. Evans, Edward H. Field, Alexandra Elise Hatem, Elizabeth H. Hearn, Kaj M Johnson, Jessica R. Murray, Peter M. Powers, Zheng-Kang Shen, Crystal Wespestad, Yuehua Zeng
GPS velocity field of the Western United States for the 2023 National Seismic Hazard Model update
Global Positioning System (GPS) velocity solutions of the western United States (WUS) are compiled from several sources of field networks and data processing centers for the 2023 U.S. Geological Survey National Seismic Hazard Model (NSHM). These solutions include both survey and continuous‐mode GPS velocity measurements. I follow the data processing procedure of Parsons et al. (2013) for the Unifo
Authors
Yuehua Zeng
Viscoelastic fault-based model of crustal deformation for the 2023 update to the U.S. National Seismic Hazard Model
The 2023 update to the National Seismic Hazard (NSHM) model is informed by several deformation models that furnish geodetically estimated fault slip rates. Here I describe a fault‐based model that permits estimation of long‐term slip rates on discrete faults and the distribution of off‐fault moment release. It is based on quantification of the earthquake cycle on a viscoelastic model of the seismo
Authors
Fred Pollitz
Earthquakes in the shadows: Why aftershocks occur at surprising locations
For decades there has been a debate about the relative effects of dynamic versus static stress triggering of aftershocks. According to the static Coulomb stress change hypothesis, aftershocks should not occur in stress shadows—regions where static Coulomb stress has been reduced. We show that static stress shadows substantially influence aftershock occurrence following three M ≥ 7 California mains
Authors
Jeanne L. Hardebeck, Ruth A. Harris
Using machine learning techniques with incomplete polarity datasets to improve earthquake focal mechanism determination
Earthquake focal mechanisms are traditionally produced using P‐wave first‐motion polarities and commonly require well‐recorded seismicity. A recent approach that is less dependent on high signal‐to‐noise exploits similar waveforms to produce relative polarity measurements between earthquake pairs. Utilizing these relative polarity measurements, it is possible to produce composite focal mechanisms
Authors
Robert Skoumal, David R. Shelly, Jeanne L. Hardebeck