Publications
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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
Western U.S. geologic deformation model for use in the U.S. National Seismic Hazard Model 2023
Fault geometry and slip rates are key input data for geologic deformation models, which are a fundamental component of probabilistic seismic hazard analyses (PSHAs). However, geologic sources for PSHA have traditionally been limited to faults with field‐based slip rate constraints, which results in underrepresentation of known, but partially characterized, active faults. Here, we evaluate fault ge
Authors
Alexandra Elise Hatem, Nadine G. Reitman, Richard W. Briggs, Ryan D. Gold, Jessica Ann Thompson Jobe, Reed J. Burgette
Mars Science Laboratory CheMin data from the Glen Torridon region and the significance of lake-groundwater interactions in interpreting mineralogy and sedimentary history
The Glen Torridon (GT) region is positioned in terrains with strong clay mineral signatures, as inferred from orbital spectroscopy. The GT campaign confirmed orbital distinctions with in situ measurements by the Mars Science Laboratory rover, Curiosity, and the CheMin X-ray diffraction instrument with of some of the highest clay mineral abundances to date. Additionally, GT is unique because of dis
Authors
Michael T. Thorpe, T. F. Bristow, E. Rampe, Nicholas Tosca, John P. Grotzinger, Kristen A. Bennett, C. N. Achilles, D. F. Blake, S. J. Chipera, G. Downs, R. T. Downs, S. M. Morrison, V. Tu, N. Castle, P. Craig, D. J. Des Marais, R. M. Hazen, D. W. Ming, R. V. Morris, A. H. Treiman, D. T. Vaniman, A. S. Yen, A. R. Vasavada, Erwin Dehouck, J. Bridges, J.O. Berger, Amy McAdam, T. Peretyazhko, K. Siebach, A. B. Bryk, V. F. Fox, Christopher M. Fedo
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
Sedimentary organics in Glen Torridon, Gale Crater, Mars: Results from the SAM instrument suite and supporting laboratory analyses
The Sample Analysis at Mars (SAM) suite instrument on board NASA's Curiosity rover has characterized the inorganic and organic chemical composition of seven samples from the Glen Torridon (GT) clay-bearing unit. A variety of organic molecules were detected with SAM using pyrolysis (up to ∼850°C) and wet chemistry experiments coupled with evolved gas analysis (EGA) and gas chromatography-mass spect
Authors
Maeva Millan, Amy Williams, Amy McAdam, Jennifer Eigenbrode, A. Steele, C Freissinet, D. P. Glavin, C. Szopa, A. Buch, Roger E. Summons, J. M. T. Lewis, G. M. Wong, C. H. House, B. Sutter, O. McIntosh, A. B. Bryk, H. B. Franz, C. Pozarycki, J. C. Stern, R. Navarro-Gonzalez, R. H. Williams, D. P. Archer, V. Fox, Kristen A. Bennett, S. Teinturier, C. Malespin, S. S. Johnson, P. R. Mahaffy
Geology and stratigraphic correlation of the Murray and Carolyn Shoemaker formations across the Glen Torridon region, Gale crater, Mars
The Glen Torridon (GT) region within Gale crater, Mars, occurs in contact with the southern side of Vera Rubin ridge (VRR), a well-defined geomorphic feature that is comparatively resistant to erosion. Prior to detailed ground-based investigation of GT, its geologic relationship with VRR was unknown. Distinct lithologic subunits within the Jura member (Murray formation), which forms the upper part
Authors
Christopher M. Fedo, Alexander Bryk, Lauren A. Edgar, Kristen A. Bennett, Valerie K. Fox, William E. Dietrich, Steve G. Banham, Sanjeev Gupta, Kathryn M. Stack, Rebecca Williams, John P. Grotzinger, Nathan Stein, Dave Rubin, Gwenael Caravaca, Ray E. Arvidson, Madison N Hughes, Abigail A. Fraeman, Ashwin R. Vasavada, Juergen Schieber, Brad Sutter
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
Comparing root cohesion estimates from three models at a shallow landslide in the Oregon Coast Range
Although accurate root cohesion model estimates are essential to quantify the effect of vegetation roots on shallow slope stability, few means exist to independently validate such model outputs. One validation approach for cohesion estimates is back-calculation of apparent root cohesion at a landslide site with well-documented failure conditions. The catchment named CB1, near Coos Bay, Oregon, USA
Authors
Collin Cronkite-Ratcliff, Kevin M. Schmidt, Charlotte Wirion