Mean Seismic Hazard Curves and Uniform-Hazard Ground Motion Values from the Revised 2023 US 50-state National Seismic Hazard Model

These hazard data accompany revisions to the 2023 50-state National Seismic Hazard Model (NSHM; Petersen and others, 2024; Petersen and others, 2022 for Hawaii; Powers and others, 2024 for Alaska) as documented in Powers and others (2026). In these revisions, we:

adjust the representation of ground motion model (GMM) epistemic uncertainty where the central and eastern U.S. (CEUS) stable-crust and the western U.S. (WUS) active-crust models are combined,
revert the weighting of the CEUS smoothed seismicity models,
apply corrections to a few CEUS fault and fault-zone polygon rupture rates and WUS gridded seismicity rates,
update the CEUS GMM non-linear site term for the softest site classes,
change the representation of magnitude (M) 7-8 earthquake ruptures on the Alaskan megathrust and fix a few input files and hazard codes, and
account for full catalog rates in Hawaii for all periods and site classes.

These data supersede the data releases of Petersen and others (2023) for the conterminous U.S. (CONUS), Alaska, and Hawaii; Altekruse and others (2024) for Alaska; and Rukstales and others (2021) for Hawaii. These superseding data include the highest resolution hazard for CONUS (0.05° grid spacing), Alaska (0.1° grid spacing), and Hawaii (0.02° grid spacing) for 21 spectral periods, peak ground acceleration, peak ground velocity, and 8 site conditions. The "CONUS.2023.R1" data include revisions #1, #2, and #3; the "CONUS.2023.R2" data additionally include revision #4, the CEUS site amplification adjustments. The “Alaska.2023.R1” and “Hawaii.2021.R2” data include revisions #5 and #6, respectively. These datasets support different building code applications as discussed in Powers and others (2026).