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U.S. Geological Survey - Geologic Hazards Science Center

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A model of the lower seismogenic depth distribution of earthquakes in the western United States was developed to support models for seismic hazard assessment that will be included in the 2023 USGS National Seismic Hazard Model. This data release presents a recalibration using the hypocentral depths of events M>1 from the Advanced National Seismic System Comprehensive Earthquake Catalog from 1980 to 2021. For higher precision and better resolution in the model, the data were supplemented with seismicity from southern California that was relocated by Hauksson and others (2012). Along the San Andreas Fault, the deepest seismogenic depths are located at 23 km around the Cholame segment, whereas the shallowest depths...
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The U. S. Geological Survey (USGS) makes long-term seismic hazard forecasts that are used in building codes. The hazard models usually consider only natural seismicity; non-tectonic (man-made) earthquakes are excluded because they are transitory or too small. In the past decade, however, thousands of earthquakes related to underground fluid injection have occurred in the central and eastern U.S. (CEUS), and some have caused damage. In response, the USGS is now also making short-term forecasts that account for the hazard from these induced earthquakes. A uniform earthquake catalog is assembled by combining and winnowing pre-existing source catalogs. Seismicity statistics are analyzed to develop recurrence models,...
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These data are supplementary to the journal article Makdisi, A.J., Kramer, S.L. (In-Review). Framework for Mapping Liquefaction Hazard-Targeted Design Ground Motions (doi to be updated on full publication). This dataset includes tabular data summarizing mean and standard deviation liquefaction factor of safety (FSL) ratios, effective FSL return periods, and example reference liquefaction-targeted design peak ground acceleration parameters (PGAL) for 96 geographic locations throughout the conterminous United States. These data were used to generate Figure 4, Figure 5, Figure 7, and Table 2 and Table 5 in the article. Notes: Procedures for calculating PGAL and FSL are detailed in Section 4.1 (Equations 2 and 3...
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The 2023 Update of the U.S. National Seismic Hazard Model defines the potential for earthquake ground shaking for various probability levels across the United States and is applied in seismic provisions of building codes, insurance rate structures, risk assessments, and other public policy. The updated model represents an assessment of the best available science in earthquake hazards and incorporates new findings on earthquake ground shaking, seismicity, and long-period amplification over deep sedimentary basins. The new model represents an update of the seismic hazard model; previous versions were developed in 1996, 2002, 2008, 2014, and 2018. This data set represents the chance of potentially damaging ground shaking...
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