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2023 U.S. National Seismic Hazard 50-State Model: Science Objectives and Products

The U.S. National Seismic Hazard Model (NSHM) is developed periodically by the USGS to account for new and improved data, models, and methods that have been developed since the previous model release. This probabilistic model is applied in building design criteria, risk assessments, and other public policy documents requiring that the best available and defensible science be considered. This 2023 NSHM will consider seismic hazard in all 50 states taking into account inherent differences in geological setting, tectonic strain rates, and earthquake rupture mechanics while allowing for more uniform methodologies and more consistent representation of epistemic uncertainties. The 2023 NSHM will be developed over the next three years and will include updates to both the source and ground motion inputs. For the statistical seismicity elements of the source model, we plan to update and decluster earthquake catalogs based on new algorithms, assess gridded seismicity rates using alternative statistical assessments, possibly evaluate application of time-dependent hazard branches, and calculate hazard. For applying new geologic and geodetic data in the source models, we are developing a database of geologic fault rupture rates and geodetic slip rates that will be used to construct multi-fault rupture models. For improving the ground motion models (GMM), we plan to update CEUS-WUS boundary, implement several new GMM including new NGA-Subduction models, consider how to better implement GMM uncertainty and variability by evaluating new nonergodic methods, and improve the assessment of ground shaking in basins using basin depth information and simulations. Several important implementation issues will also consider better non-linear ground shaking estimates for the CEUS, assessment of hazard near basin edges, and implementation of uncertainty analysis. Public workshops over the next three years will allow for critical discussions on important elements of the NSHMs.

Presenting Author: Mark D. Petersen

Student Presenter: No

Day: 4/21/2021

Time: 9:45 AM - 11:00 AM Pacific

Additional Authors