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Simplifying complex fault data for systems-level analysis: Earthquake geology inputs for U.S. NSHM 2023
Alexandra E Hatem1, Camille M Collett2, Richard W Briggs2
1U.S. Geological Survey, Geologic Hazards Science Center, 1711 Illinois St, Golden, CO, 80401, USA. ahatem@usgs.gov.
Scientific Data
|August 18, 2022
Summary
New seismic hazard models for the western U.S. now include more faults. Expanded databases represent Quaternary-active faulting more completely for the National Seismic Hazard Model update.
Area of Science:
- Geophysics
- Seismology
- Earth Science
Background:
- The U.S. National Seismic Hazard Model (NSHM) requires comprehensive fault data.
- Previous NSHM iterations were limited by inclusion criteria for fault slip rates.
Purpose of the Study:
- To develop updated fault databases for the 2023 NSHM.
- To more completely represent Quaternary-active faulting in the western United States.
Main Methods:
- Compiled two new databases: NSHM23 fault sections database (FSD) and earthquake geology database (EQGeoDB).
- Expanded inclusion criteria to assess a larger set of faults.
- Utilized the USGS Quaternary Fault and Fold Database as a guide.
- Reevaluated published data to identify additional fault sections.
Main Results:
- Increased the number of fault sections from approximately 650 (NSHM18) to about 1,000 for NSHM23.
- EQGeoDB provides geologic slip rate estimates linked to the NSHM23 FSD.
- The expanded datasets offer a more complete representation of active faulting.
Conclusions:
- The new databases provide crucial input for NSHM development.
- These datasets support deformation modeling and earthquake rupture forecasting.
- Enhanced fault representation improves seismic hazard assessment.
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