VS30, the time-averaged shear-wave velocity (VS) to a depth of 30 meters, is a key index adopted by the earthquake engineering community to account for seismic site conditions. VS30 is typically based on geophysical measurements of VS derived from invasive and noninvasive techniques at sites of interest. Owing to cost considerations, as well as logistical and environmental concerns, VS30 data are sparse or not readily available for most areas. Where data are available, VS30 values are often assembled in assorted formats that are accessible from disparate and (or) impermanent Websites. To help remedy this situation, we compiled VS30 measurements obtained by studies funded by the U.S. Geological Survey (USGS) and other governmental agencies. Thus far, we have compiled VS30 values for 4,369 sites in the United States, along with metadata for each measurement from government-sponsored reports, online databases, and scientific and engineering journals. Most of the data in our VS30 compilation originated from publications directly reporting the work of field investigators. A subset consisting of 20 percent of VS30 values was previously compiled by the USGS and other research institutions. VS30 originating from these earlier compilations were crosschecked against published reports when clarification was needed. Both downhole and surface-based VS30 estimates are represented in our VS30 compilation. Most of the VS30 data are for sites in the western contiguous United States (3,128 sites); 682 VS30 values are for sites in the Central United States; 267 VS30 values are for sites in the Eastern United States and Puerto Rico; 15 VS30 values are for sites in Alaska; 30 VS30 values are for sites in Hawaii. The remaining 247 sites are in the vicinity of Vancouver, Canada.

A global, mosaiced (hybrid resolution) model of Vs30.

This database complements the following publication: "A Ground Motion Model for GNSS Peak Ground Displacement", by Goldberg, D.E., et al., submitted to Bulletin of the Seismological Society of America, June 2021. High-rate Global Navigations Satellite Systems (GNSS) data is recognized as a valuable complement to traditional inertial seismic instrumentation for recording the large ground motions at regional distances to large magnitude earthquakes. This dataset contains high-rate GNSS displacement waveforms, processed using precise point positioning, for a global set of moderate- to large-magnitude earthquakes (Mw6-9) between the years 2003 and 2019. The peak ground displacement observed at nearby stations are summarized in the text file under "Peak Ground Displacement Observations". Also included are a set of one or more finite fault models for each earthquake in the dataset. Refer to the table "Finite Fault Model Metadata" under "Finite Fault Models" for the earthquake location information and original reference for each available finite fault model.

This Data Release contains version 3.0 of two related earthquake geology databases for use in the 2023 U.S. National Seismic Hazard Model. The databases are: 1) A fault sections database (“NSHM23_FSD_v3”), which depicts the geometry of faults capable of hosting independent earthquakes, and 2) an earthquake geology site information database (“NSHM23_EQGeoDB_v3”), which contains fault slip rate constraints at points. These databases cover the 12 western U.S. states: Washington, Oregon, California, Idaho, Nevada, Arizona, Montana, Wyoming, Colorado, New Mexico and Texas. Datasets containing crustal fault information for Alaska and the central and eastern United States were prepared by Bender and others, 2021 and Thompson Jobe and others, 2023 in separate efforts. The two databases are broken into separate child items from this landing page. The databases are provided as geospatial data (.SHP, .KML, and GeoJSON file formats) and tables (.CSV format). Reference information, including change log, version notes, and a README, are included as "Attached Files" below this Summary. Versioning These databases are updated as of December 2023 (version 3.0), which supersede the databases release in February 2022 (version 2.0) and the January 2021 (version 1.0) preliminary datasets. After significant testing by many user groups, this version 3.0 data release contains minor changes. The specific changes made in the fault sections database (FSD) from version 2.0 (2022) to version 3.0 (2023; this release) are outlined in "NSHM23_FSD_v2-v3_VersionChanges.txt." The changes to the EQGeoDB involve fixing typos and further populating the reference list to include UCERF3 references; the authors acknowledge Scott Marshall (Appalachian State University) for uncovering these additional references. Note on the Cheraw fault: At the time of original compilation (2020-2021), the Cheraw fault of Colorado was included in the western U.S. fault sections database. During model implementation, the Cheraw fault was instead treated as a central and eastern U.S. fault. To maintain consistency with earlier releases, we retain the Cheraw fault geometry and attributes in this table. For more information, please review Shumway and others., in press manuscript about CEUS fault implementation. For more information on how these datasets were compiled, please refer to our manuscript publication, Hatem and others, 2022. References Cited Bender, A.M., Haeussler, P.J. and Powers, P.M., 2021, Geologic inputs for the 2023 Alaska update to the U.S. National Seismic Hazard Model (NSHM) (ver. 2.0, February 2023): U.S. Geological Survey data release, https://doi.org/10.5066/P97NRR0F Hatem, A.E., Collett, C.M., Briggs, R.W., Gold, R.D., Angster, S.J., Field, E.H., Powers, P.M. and the Earthquake Geology Working Group, 2022, Simplifying complex fault data for systems-level analysis: Earthquake geology inputs for US NSHM 2023. Scientific data, 9(1), 506. https://doi.org/10.1038/s41597-022-01609-7 Shumway, A.M., Petersen, M.D., Powers, P.M., Toro, G., Altekruse, J. M., Herrick, J.A., Rukstales, K.S., Thompson Jobe, J.A., Hatem, A.E., and Girot, D.L., in press, Earthquake Rupture Forecast Model Construction for the 2023 U.S. 50-State National Seismic Hazard Model Update: Central and Eastern U.S. Fault-Based Source Model. Seismological Research Letters. Thompson Jobe, J.A., Hatem, A.E., Gold, R.D., DuRoss, C., Reitman, N.G., Briggs, R.W., and Collett, C.M., 2022, Earthquake geology inputs for the National Seismic Hazard Model (NSHM) 2023 (central and eastern United States), version 1.0: U.S. Geological Survey data release, https://doi.org/10.5066/P94HLE5G

This Data Release contains preliminary versions of two related databases: 1) A fault sections database (“NSHM23_FSD_v2”), which depicts the geometry of faults capable of hosting independent earthquakes, and 2) An earthquake geology site information database (“NSHM23_EQGeoDB_v2”), which contains fault slip-rate constraints at points. These databases were prepared in anticipation of updates to the National Seismic Hazard Model (NSHM) 2023. Fault-specific geologic parameters for the NSHM have not been updated since the 2014 NSHM release. The datasets include the states of Washington, Oregon, California, Idaho, Nevada, Arizona, Montana, Wyoming, Colorado, New Mexico and Texas. Datasets containing fault information for Alaska and the Central and Eastern United States will be the subject of future efforts. These databases are provided as geospatial data (e.g., .SHP and .GeoJSON file formats) and tables (.CSV or .TXT format). Please note: these databases are updated as of February 2022 (version 2), which supersede the databases release in January 2021 (version 1).

Global positioning system (GPS) data were compiled and processed to support models for seismic hazard assessment that will be included in the 2023 USGS National Seismic Hazard Model (NSHM). This data release presents the updated GPS velocity field for the western United States. Data processing centers and field networks, seven in total, supported this work, and solutions include both survey and continuous-mode GPS velocity measurements. Processing procedures were followed according to the UCERF3 (Uniform California Earthquake Rupture Forecast version 3) and the 2014 NSHM deformation modeling project. The final velocity field consists of 4,979 horizontal velocity vectors.

Seismicity catalogs, gridded seismic hazard curve data, gridded ground motion data, and mapped gridded ground motion values are available for the 2002 National Seismic Hazard Model for the Conterminous U.S. Seismicity catalogs are available for the western U.S. (in Mw) and central and eastern U.S. (in mb). Probabilistic seismic hazard data and maps of the conterminous U.S. for peak ground acceleration (PGA) and 0.1, 0.2, 0.3, 0.5, 1.0 and 2.0 second spectral acceleration at probability levels of 2 percent in 50 years (annual probability of 0.000404) and 10 percent in 50 years (annual probability of 0.0021), assuming firm rock soil conditions at 760 m/s, are available. Hazard was calculated on a 0.1 degree by 0.1 degree grid, defined by a bounding box encompassing the conterminous U.S. (-125 to -65 degrees longitude west, 24.6 to 50 degrees latitude north). Development of the 2002 National Seismic Hazard Model for the Conterminous U.S. is documented in the USGS Open-File Report 02-420 (https://pubs.usgs.gov/of/2002/ofr-02-420/). This dataset is considered a legacy dataset. The original dataset was uploaded to the USGS website at the time of publication of the seismic hazard model (2002) but was later moved over the the USGS ScienceBase Catalog (2019). The original dataset was assumed to be complete and accurate, but may contain inconsistencies when compared to more recent, actively maintained datasets.

The updated 2018 National Seismic Hazard Model includes new ground motion models, aleatory uncertainty, and soil amplification factors for the central and eastern U.S. and incorporates basin depths from local seismic velocity models in four western U.S. (WUS) urban areas. These additions allow us, for the first time, to calculate probabilistic seismic hazard curves for an expanded set of spectral periods (0.01 s to 10 s) and site classes (VS30 = 150 m/s to 1,500 m/s) for the conterminous U.S. (CONUS), as well as account for amplification of long-period ground motions in deep sedimentary basins in the Los Angeles, San Francisco Bay, Salt Lake City, and Seattle regions. Ground motion data for 2, 5, and 10 percent probability of exceedance in 50 years have been derived from these hazard curves.Two sets of data are available: (1) 0.05 by 0.05 degree gridded hazard data for the CONUS and (2) 0.01 by 0.01 degree gridded hazard data for WUS basins. Note that both sets of data contain basin amplification in deep sedimentary basins in the WUS. The 0.01 degree by 0.01 degree data simply provides a higher resolution dataset than then 0.05 degree by 0.05 degree dataset. This dataset is discussed in the journal article titled: "The 2018 update of the US National Seismic Hazard Model: Additional period and site class data" by Shumway et al. (2021) located at https://doi.org/10.1177/8755293020970979. First Posted - October 7, 2019 Revised - February 2020 (ver 1.1) Revised - May 2021 (ver 1.2)

This dataset presents where, why, and how much probabilisitic ground motions have changed with the 2018 update of the National Seismic Hazard Model (NSHM) for the conterminous U.S. (CONUS) vs. the 2014 NSHM. In the central and eastern U.S., hazard changes are the result of updated ground motion models (further broken down by median and epistemic uncertainty, aleatory variability, and site effects models) and gridded seismicity models. In the western U.S., hazard changes are the result of updated ground motion models in four urban areas with deep sedimentary basins and gridded seismicity models. Probabilistic ground motion changes (2% in 50 years probability of exceedance for a firm rock site, VS30 = 760 m/s) are presented for 153,255 sites across the CONUS for 0.2s and 1s spectral acceleration. A MATLAB script is provided so that the dataset can be searched by site location. A statistical analysis of the dataset was also performed and is provided in a table (Table 1).