Rich Briggs
My work focuses on the geology and seismotectonics of large earthquakes, with the goal of understanding how, where, and why they happen.
Research Focus
I characterize active faults for seismic hazard analysis. This requires grappling with structures and processes that control earthquakes. I also work with the USGS National Earthquake Information Center (NEIC) to respond to large earthquakes by conducting rapid field studies and analyzing remote sensing products.
Professional Preparation
BS, Geologic and Environmental Science, Stanford University, 1999
PhD, Geology, Center for Neotectonic Studies, University of Nevada, Reno, 2004
Postdoctoral Scholar, Tectonics Observatory, California Institute of Technology, 2005-2008
Professional Experience
Research Geologist, U.S. Geological Survey, Golden, CO, 2008-present
Geologist, Synergetics Incorporated, Fort Collins, CO (contracted to USGS), 2008
Science and Products
Coseismic slip and early afterslip of the 2015 Illapel, Chile, earthquake: Implications for frictional heterogeneity and coastal uplift
Terrestrial cosmogenic surface exposure dating of glacial and associated landforms in the Ruby Mountains-East Humboldt Range of central Nevada and along the northeastern flank of the Sierra Nevada
Coral 13C/12C records of vertical seafloor displacement during megathrust earthquakes west of Sumatra
Rapid characterization of the 2015 Mw 7.8 Gorkha, Nepal, earthquake sequence and its seismotectonic context
Unusually large tsunamis frequent a currently creeping part of the Aleutian megathrust
Reactivated faulting near Cushing, Oklahoma: Increased potential for a triggered earthquake in an area of United States strategic infrastructure
A random-walk algorithm for modeling lithospheric density and the role of body forces in the evolution of the Midcontinent Rift
On- and off-fault deformation associated with the September 2013 Mw7.7 Balochistan earthquake: Implications for geologic slip rate measurements
Tsunami recurrence in the eastern Alaska-Aleutian arc: A Holocene stratigraphic record from Chirikof Island, Alaska
Updating the USGS seismic hazard maps for Alaska
Beach ridges as paleoseismic indicators of abrupt coastal subsidence during subduction zone earthquakes, and implications for Alaska-Aleutian subduction zone paleoseismology, southeast coast of the Kenai Peninsula, Alaska
High‐resolution trench photomosaics from image‐based modeling: Workflow and error analysis
Science and Products
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Filter Total Items: 57
Coseismic slip and early afterslip of the 2015 Illapel, Chile, earthquake: Implications for frictional heterogeneity and coastal uplift
Great subduction earthquakes are thought to rupture portions of the megathrust, where interseismic coupling is high and velocity-weakening frictional behavior is dominant, releasing elastic deformation accrued over a seismic cycle. Conversely, postseismic afterslip is assumed to occur primarily in regions of velocity-strengthening frictional characteristics that may correlate with lower interseismAuthorsWilliam D. Barnhart, Jessica R. Murray, Richard W. Briggs, Francisco Gomez, Charles P. J. Miles, Jerry L. Svarc, Sebástian Riquelme, Bryan J. StresslerTerrestrial cosmogenic surface exposure dating of glacial and associated landforms in the Ruby Mountains-East Humboldt Range of central Nevada and along the northeastern flank of the Sierra Nevada
Deposits near Lamoille in the Ruby Mountains-East Humboldt Range of central Nevada and at Woodfords on the eastern edge of the Sierra Nevada each record two distinct glacial advances. We compare independent assessments of terrestrial cosmogenic nuclide (TCN) surface exposure ages for glacial deposits that we have determined to those obtained by others at the two sites. At each site, TCN ages of boAuthorsSteven G. Wesnousky, Richard W. Briggs, Marc W. Caffee, Rick J. Ryerson, Robert C. Finkel, Lewis A. OwenCoral 13C/12C records of vertical seafloor displacement during megathrust earthquakes west of Sumatra
The recent surge of megathrust earthquakes and tsunami disasters has highlighted the need for a comprehensive understanding of earthquake cycles along convergent plate boundaries. Space geodesy has been used to document recent crustal deformation patterns with unprecedented precision, however the production of long paleogeodetic records of vertical seafloor motion is still a major challenge. HereAuthorsMichael K. Gagan, Sindia M. Sosdian, Heather Scott-Gagan, Kerry Sieh, Wahyoe S. Hantoro, Danny H. Natawidjaja, Richard W. Briggs, Bambang W. Suwargadi, Hamdi RifaiRapid characterization of the 2015 Mw 7.8 Gorkha, Nepal, earthquake sequence and its seismotectonic context
Earthquake response and related information products are important for placing recent seismic events into context and particularly for understanding the impact earthquakes can have on the regional community and its infrastructure. These tools are even more useful if they are available quickly, ahead of detailed information from the areas affected by such earthquakes. Here we provide an overview ofAuthorsGavin P. Hayes, Richard W. Briggs, William D. Barnhart, William L. Yeck, Daniel E. McNamara, David J. Wald, Jennifer Nealy, Harley M. Benz, Ryan D. Gold, Kishor S. Jaiswal, Kristin Marano, Paul S. Earle, Mike Hearne, Gregory M. Smoczyk, Lisa A. Wald, Sergey SamsonovUnusually large tsunamis frequent a currently creeping part of the Aleutian megathrust
Current models used to assess earthquake and tsunami hazards are inadequate where creep dominates a subduction megathrust. Here we report geological evidence for large tsunamis, occurring on average every 300–340 years, near the source areas of the 1946 and 1957 Aleutian tsunamis. These areas bookend a postulated seismic gap over 200 km long where modern geodetic measurements indicate that the megAuthorsRobert C. Witter, G. A. Carver, Richard W. Briggs, Guy R. Gelfenbaum, R.D. Koehler, SeanPaul M. La Selle, Adrian M. Bender, S.E. Engelhart, E. Hemphill-Haley, Troy D. HillReactivated faulting near Cushing, Oklahoma: Increased potential for a triggered earthquake in an area of United States strategic infrastructure
In October 2014 two moderate-sized earthquakes (Mw 4.0 and 4.3) struck south of Cushing, Oklahoma, below the largest crude oil storage facility in the world. Combined analysis of the spatial distribution of earthquakes and regional moment tensor focal mechanisms indicate reactivation of a subsurface unnamed and unmapped left-lateral strike-slip fault. Coulomb failure stress change calculations usiAuthorsDaniel E. McNamara, Gavin P. Hayes, Harley M. Benz, Robert Williams, Nicole D McMahon, R.C. Aster, Austin F. Holland, T Sickbert, Robert B. Herrmann, Richard W. Briggs, Gregory M. Smoczyk, Eric Bergman, Paul S. EarleA random-walk algorithm for modeling lithospheric density and the role of body forces in the evolution of the Midcontinent Rift
This paper develops a Monte Carlo algorithm for extracting three-dimensional lithospheric density models from geophysical data. Empirical scaling relationships between velocity and density create a 3D starting density model, which is then iteratively refined until it reproduces observed gravity and topography. This approach permits deviations from uniform crustal velocity-density scaling, which prAuthorsWilliam Brower Levandowski, Oliver S. Boyd, Richard W. Briggs, Ryan D. GoldOn- and off-fault deformation associated with the September 2013 Mw7.7 Balochistan earthquake: Implications for geologic slip rate measurements
The 24 September 2013 Mw7.7 Balochistan, Pakistan earthquake ruptured a ~ 200 km-long stretch of the Hoshab fault in southern Pakistan and produced the second-largest lateral surface displacement observed for a continental strike-slip earthquake. We remotely measured surface deformation associated with this event using high-resolution (0.5 m) pre- and post-event satellite optical imagery. We documAuthorsRyan D. Gold, Nadine G. Reitman, Richard W. Briggs, William D. Barnhart, Gavin P. Hayes, Earl M. WilsonTsunami recurrence in the eastern Alaska-Aleutian arc: A Holocene stratigraphic record from Chirikof Island, Alaska
Despite the role of the Alaska-Aleutian megathrust as the source of some of the largest earthquakes and tsunamis, the history of its pre–twentieth century tsunamis is largely unknown west of the rupture zone of the great (magnitude, M 9.2) 1964 earthquake. Stratigraphy in core transects at two boggy lowland sites on Chirikof Island’s southwest coast preserves tsunami deposits dating from the postgAuthorsAlan R. Nelson, Richard W. Briggs, Tina Dura, Simon E. Engelhart, Guy Gelfenbaum, Lee-Ann Bradley, S.L. Forman, Christopher H. Vane, K.A. KelleyUpdating the USGS seismic hazard maps for Alaska
The U.S. Geological Survey makes probabilistic seismic hazard maps and engineering design maps for building codes, emergency planning, risk management, and many other applications. The methodology considers all known earthquake sources with their associated magnitude and rate distributions. Specific faults can be modeled if slip-rate or recurrence information is available. Otherwise, areal sourcesAuthorsCharles Mueller, Richard W. Briggs, Robert L. Wesson, Mark D. PetersenBeach ridges as paleoseismic indicators of abrupt coastal subsidence during subduction zone earthquakes, and implications for Alaska-Aleutian subduction zone paleoseismology, southeast coast of the Kenai Peninsula, Alaska
The Kenai section of the eastern Alaska-Aleutian subduction zone straddles two areas of high slip in the 1964 great Alaska earthquake and is the least studied of the three megathrust segments (Kodiak, Kenai, Prince William Sound) that ruptured in 1964. Investigation of two coastal sites in the eastern part of the Kenai segment, on the southeast coast of the Kenai Peninsula, identified evidence forAuthorsHarvey M. Kelsey, Robert C. Witter, Simon E. Engelhart, Richard W. Briggs, Alan R. Nelson, Peter J. Haeussler, D. Reide CorbettHigh‐resolution trench photomosaics from image‐based modeling: Workflow and error analysis
Photomosaics are commonly used to construct maps of paleoseismic trench exposures, but the conventional process of manually using image‐editing software is time consuming and produces undesirable artifacts and distortions. Herein, we document and evaluate the application of image‐based modeling (IBM) for creating photomosaics and 3D models of paleoseismic trench exposures, illustrated with a case‐AuthorsNadine G. Reitman, Scott E. K. Bennett, Ryan D. Gold, Richard W. Briggs, Christopher DuRoss - Software