Geologic Hazards Science Center
Publications
Localized fault-zone dilatancy and surface inelasticity of the 2019 Ridgecrest earthquakes
Earthquakes produce a spectrum of elastic and inelastic deformation processes that are reflected across various length and time scales. While elasticity has long dominated research assumptions in active tectonics, increasing interest has focused on the inelastic characteristics of earthquakes, particularly those of the surface fault rupture zone...
Barnhart, William D.; Gold, Ryan D.; Hollingsworth, James Identifying the greatest earthquakes of the past 2000 years at the Nehalem River Estuary, Northern Oregon Coast, USA
We infer a history of three great megathrust earthquakes during the past 2000 years at the Nehalem River estuary based on the lateral extent of sharp (≤3 mm) peat-mud stratigraphic contacts in cores and outcrops, coseismic subsidence as interpreted from fossil diatom assemblages and reconstructed with foraminiferal assemblages using a Bayesian...
Nelson, Alan R.; Hawkes, Andrea D.; Sawai, Yuki; Engelhart, Simon E.; Witter, Robert C.; Grant-Walter, Wendy C.; Bradley, Lee-Ann; Dura, Tina; Cahill, Niamh; Horton, Benajamin P. Selecting three components of ground motions from Conditional Spectra for multiple stripe analyses
For complex structures where the seismic response depends appreciably on the vertical (V) component of ground motion (GM) (e.g., base-isolated buildings, long-span bridges, dams, nuclear power plants), incremental dynamic analysis (IDA) is commonly utilized to estimate seismic risk, where the V components of GM are selected and scaled based on the...
Kwong, Neal (Simon) S; Jaiswal, Kishor; Luco, Nicolas; Baker, J.W. Simultaneous observations of geoelectric and geomagnetic fields produced by magnetospheric ULF waves
Geomagnetic perturbations (BGEO) related to magnetospheric ultralow frequency (ULF) waves induce electric fields within the conductive Earth—geoelectric fields (EGEO)—that in turn drive geomagnetically induced currents. Though numerous past studies have examined ULF wave BGEO from a space weather perspective, few studies have linked ULF...
Hartinger, M. D.; Shih, X. R.; Lucas, G.; Murphy, Benjamin Scott; Kelbert, Anna; Baker, J.B.H.; Rigler, E. Joshua; Bedrosian, Paul A.
Geomagnetism Program research plan, 2020–2024
The Geomagnetism Program of the U.S. Geological Survey (USGS) monitors geomagnetic field variation through operation of a network of observatories across the United States and its territories, and it pursues scientific research needed to estimate and assess geomagnetic and geoelectric hazards. Over the next five years (2020–2024 inclusive) and in...
Love, Jeffrey J.; Kelbert, Anna; Murphy, Benjamin S.; Rigler, E. Joshua; Lewis, Kristen A.
Earthquake information products and tools from the Advanced National Seismic System (ANSS)
This Fact Sheet describes post-earthquake products and tools provided by the Advanced National Seismic System (ANSS) through the U.S. Geological Survey Earthquake Hazards Program. The focus is on products that provide situational awareness immediately after significant earthquakes.
Wald, Lisa A. Measuring basal force fluctuations of debris flows using seismic recordings and empirical green's functions
We present a novel method for measuring the fluctuating basal normal and shear stresses of debris flows by using along‐channel seismic recordings. Our method couples a simple parameterization of a debris flow as a seismic source with direct measurements of seismic path effects using empirical Green's functions generated with a force hammer. We...
Allstadt, Kate; Farin, Maxime; Iverson, Richard M.; Obryk, Maciej; Kean, Jason W.; Tsai, Victor C.; Rapstine, Thomas D; Logan, Matthew The recurrence interval of post-fire debris-flow generating rainfall in the southwestern United States
In the southwestern United States, post-fire debris flows commonly initiate during short bursts of intense rainfall. To date, the frequency of the rainfall rates has not been quantified. Here, we combine an existing database of debris-flow occurrences and corresponding peak storm intensities with a geospatial library of rainfall recurrence...
Staley, Dennis M.; Kean, Jason W.; Rengers, Francis K. Hillslopes in humid-tropical climates aren’t always wet: Implications for hydrologic response and landslide initiation in Puerto Rico, USA
The devastating impacts of the widespread flooding and landsliding in Puerto Rico following the September 2017 landfall of Hurricane Maria highlight the increasingly extreme atmospheric disturbances and enhanced hazard potential in mountainous humid‐tropical climate zones. Long‐standing conceptual models for hydrologically driven hazards in Puerto...
Thomas, Matthew A.; Mirus, Benjamin B.; Smith, Joel B. Landslides after wildfire: Initiation, magnitude, and mobility
In the semiarid Southwestern USA, wildfires are commonly followed by runoff-generated debris flows because wildfires remove vegetation and ground cover, which reduces soil infiltration capacity and increases soil erodibility. At a study site in Southern California, we initially observed runoff-generated debris flows in the first year following...
Rengers, Francis K.; McGuire, Luke; Oakley, Nina S.; Kean, Jason W.; Staley, Dennis M.; Tang, Hui
Adjusted geomagnetic data—Theoretical basis and validation
Adjusted geomagnetic data are magnetometer measurements with provisional correction factors applied such that vector quantities are oriented in a local Cartesian frame in which the X axis points north, the Y axis points east, and the Z axis points down. These correction factors are determined from so-called absolute measurements, which are “ground...
Rigler, E. Joshua; Claycomb, Abram E.
Calibration of the U.S. Geological Survey National Crustal Model
The U.S. Geological Survey National Crustal Model (NCM) is being developed to include spatially varying estimates of site response in seismic hazard assessments. Primary outputs of the NCM are continuous velocity and density profiles from the Earth’s surface to the mantle transition zone at 410-kilometer (km) depth for each location on a 1-km grid...
Boyd, Oliver S.