We have developed a new three-dimensional seismic velocity model of the central United States (CUSVM) that includes the New Madrid Seismic Zone (NMSZ) and covers parts of Arkansas, Mississippi, Alabama, Illinois, Missouri, Kentucky, and Tennessee. The model represents a compilation of decades of crustal research consisting of seismic, aeromagnetic, and gravity profiles; geologic mapping; geophysical and geological borehole logs; and inversions of the regional seismic properties. The density and P- and S-wave velocities are synthesized in a stand-alone spatial database that can be queried to generate the required input for numerical seismic-wave propagation simulations. The velocity model has been tested and calibrated by simulating ground motions of the 18 April 2008 Mw 5.4 Mt. Carmel, Illinois, earthquake and comparing the results with observed records within the model area (see associated publication).

This Data Release contains preliminary versions of two related databases: 1) A fault sections database (“NSHM2023_FaultSections_v1”), which depicts the geometry of faults capable of hosting independent earthquakes, and 2) An earthquake geology site information database (“NSHM2023_EQGeoDB_v1”), 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, .KML, .GeoJSON file formats) and tables (.CSV format).

This Data Release contains preliminary versions of two related databases: 1) A fault sections database (“NSHM2023_FaultSections_v1”), which depicts the geometry of faults capable of hosting independent earthquakes, and 2) An earthquake geology site information database (“NSHM2023_EQGeoDB_v1”), 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, .KML, .GeoJSON file formats) and tables (.CSV format).

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).

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)

The 2014 update of the U.S. Geological Survey (USGS) National Seismic Hazard Model (NSHM) for the conterminous United States (2014 NSHM; Petersen and others, 2014; https://pubs.usgs.gov/of/2008/1128/) included probabilistic ground motion maps for 2 percent and 10 percent probabilities of exceedance in 50 years, derived from seismic hazard curves for peak ground acceleration (PGA) and 0.2 and 1.0 second spectral accelerations (SAs) with 5 percent damping for the National Earthquake Hazards Reduction Program (NEHRP) site class boundary B/C (time-averaged shear wave velocity in the upper 30 meters [VS30]=760 meters per second [m/s]). This data release provides 0.1 degree by 0.1 degree gridded seismic hazard curves, 0.1 degree by 0.1 degree gridded probabilistic ground motions, and seismic hazard maps calculated for additional periods and additional uniform NEHRP site classes using the 2014 NSHM. For both the central and eastern U.S. (CEUS) and western U.S. (WUS), data and maps are provided for PGA, 0.1, 0.2, 0.3, 0.5, 1.0, and 2.0 second SAs with 5% damping for the NEHRP site class boundary B/C for 2, 5, and 10% probabilities of exceedance in 50 years. The WUS additionally includes data and maps for 0.75, 3.0, 4.0, and 5.0 SAs. The use of region-specific suites of weighted ground motion models (GMMs) in the 2014 NSHM precluded the calculation of ground motions for a uniform set of periods and site classes for the conterminous U.S. At the time of development of the 2014 NSHM, there was no consensus in the CEUS on an appropriate site-amplification model to use, therefore, we calculated hazard curves and maps for NEHRP Site Class A (VS30 = 2000 m/s), for which most stable continental GMMs were original developed, based on simulations for hard rock conditions. In the WUS, however, the GMMs allow amplification based on site class (defined by VS30), so we calculated hazard curves and maps for NEHRP site classes B (VS30 = 1080 m/s), C (VS30 = 530 m/s), D (VS30 = 260 m/s), and E (VS30 = 150 m/s) and site class boundaries A/B (VS30 = 1500 m/s), B/C (VS30 = 760 m/s), C/D (VS30 = 365 m/s), and D/E (VS30 = 185 m/s). Further explanation about how the data and maps were generated can be found in the accompanying U.S. Geological Survey Open-File Report 2018-1111 (https://doi.org/10.3133/ofr20181111). First Posted - July 18, 2018 Revised - February 20, 2019 (ver. 1.1)

Seismicity catalogs, GIS shapefiles, gridded seismic hazard curve data, gridded ground motion data, and mapped gridded ground motion values are available for the 2014 National Seismic Hazard Model for the Conterminous U.S. Probabilistic seismic hazard data and maps of the conterminous U.S. for peak ground acceleration (PGA) and 0.2 and 1.0 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 0.05 degree by 0.05 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 2014 National Seismic Hazard Model for the Conterminous U.S. is documented in the USGS Open-File Report 2014-1091 (https://pubs.usgs.gov/of/2014/1091/). 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 (2014) 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.

Seismicity catalogs, gridded seismic hazard curve data, gridded ground motion data, and mapped gridded ground motion values are available for the 2008 National Seismic Hazard Model for the Conterminous U.S. (1) Seismicity catalogs are available for the western U.S. (in Mw) and central and eastern U.S. (in mb). (2) Gridded (0.05 degree by 0.05 degree) ground motion values and hazard maps are available for peak ground acceleration (PGA) and 0.1, 0.2, 0.3, 0.5, 1.0, and 2.0 second spectral acceleration (SA) at probability levels of 2% in 50 years (annual probability of 0.000404), 5% in 50 years (annual probability of 0.001026), and 10% in 50 years (annual probability of 0.0021), assuming firm rock soil conditions at 760 m/s, for the conterminous U.S. (US). Additional periods (0.75s, 3s, 4s, and 5s) are available for the western U.S. (WUS). Data was derived from the probabilistic seismic hazard curves. (3) Gridded (0.1 degree by 0.1 degree) ground motion values and hazard maps are available for peak ground acceleration (PGA) and 0.1, 0.2, 0.3, 0.5, 1.0, and 2.0 second spectral acceleration (SA) at probability levels of 2% in 50 years (annual probability of 0.000404), 5% in 50 years (annual probability of 0.001026), and 10% in 50 years (annual probability of 0.0021), assuming hard rock site conditions at 2,000 m/s, for the central and eastern U.S. (CEUS). Data was derived from the probabilistic seismic hazard curves. (4) Gridded (0.05 degree by 0.05 degree) ground motion values and hazard maps are available for peak ground acceleration (PGA) and 0.1, 0.2, 0.3, 0.5, 0.75s, 1.0, 2.0, 3.0, 4.0, and 5.0 second spectral acceleration (SA) at probability levels of 2% in 50 years (annual probability of 0.000404), 5% in 50 years (annual probability of 0.001026), and 10% in 50 years (annual probability of 0.0021), for VS30 values of 1,150 m/s, 537 m/s, 360 m/s, 259 m/s, and 180 m/s, for the western U.S. (WUS). Data was derived from the probabilistic seismic hazard curves. Development of the 2008 National Seismic Hazard Model for the Conterminous U.S. is documented in the USGS Open-File Report 2008-1128 (https://doi.org/10.3133/ofr20081128). 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 (2008) 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.

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