Data Release for the 2023 U.S. 50-State National Seismic Hazard Model - Overview

The U.S. National Seismic Hazard Model (NSHM) was updated in 2023 for all 50 states using the best available science related to earthquake seismicity, fault ruptures, ground motions, and hazard estimation techniques to produce a standard of practice for public policy applications. Best available or applicable science is defined here as well-vetted and published hazard input component models and information that are accepted through a comprehensive review process, consistent with open and timely science principles, and encompass a scientifically reasonable range of earthquake characteristics and ground motion effects that improve the basis of the 2023 NSHM. This time-independent probabilistic seismic hazard model benefited from several dozens of co-authors, more than 50 reviewers, and hundreds of end-users, and hazard scientists that attended the public workshops and provided technical inputs and reviews of the inputs and their integration in the hazard assessment. The hazard assessment applies new earthquake catalogs, declustering algorithms, gridded seismicity models, magnitude-scaling equations, fault-based structural and deformation models, multi-fault earthquake rupture forecast models, semi-empirical and simulation-based ground motion models, and site amplification models conditioned on velocities of the upper 30 m of soil and deeper sedimentary structure. Resulting seismic hazard calculations yield hazard curves, maps, uniform hazard response spectra, and disaggregations which are developed for spectral accelerations at 21 oscillator periods, two peak parameters, and eight site classes that are now required by the 2020 NEHRP Recommended Seismic Provisions and applied in multiple other public policy products. A system-level test is performed to ensure the resulting ground motions are consistent with historical intensity information. Several impact products including building seismic design criteria, intensity maps (Modified Mercalli Intensity), ground motion scenarios, and engineering risk assessments that show the potential physical and social impacts and provide a basis for assessing, planning, and mitigating the effects of future earthquakes across the U.S.

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  "010:12"
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  "geospatial"
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