Revised earthquake geology inputs for the central and eastern United States and southeast Canada for the 2023 National Seismic Hazard Model

Jessica A. Thompson Jobe; Alexandra Elise Hatem; Ryan D. Gold; Christopher B. DuRoss; Nadine G. Reitman; Richard W. Briggs; Camille Marie Collett

doi:10.1785/0220220162

USGS · 70269055

Revised earthquake geology inputs for the central and eastern United States and southeast Canada for the 2023 National Seismic Hazard Model

Jessica A. Thompson Jobe·Alexandra Elise Hatem·Ryan D. Gold·Christopher B. DuRoss·Nadine G. Reitman·Richard W. Briggs·Camille Marie Collett

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Abstract

It has been nearly a decade since updates to seismic and fault sources in the central and eastern United States (CEUS) were last assessed for the 2012 Central and Eastern United States Seismic Source Characterization for nuclear facilities (CEUS-SSCn) and 2014 United States Geological Survey National Seismic Hazard Model (NSHM) for the conterminous U.S. In advance of the 2023 NSHM update, we created 3 related geospatial databases to summarize and characterize new fault source information for the CEUS. These include fault section, fault-zone polygon, and earthquake geology (fault slip rate, earthquake recurrence intervals) databases which document updates to fault parameters used in prior seismic hazard models in this region. The 2012 CEUS-SSCn and 2014 NSHM fault models served as a foundation, as we revised and added fault sources where new published studies documented significant changes to our understanding of fault location, geometry, or activity. We added 9 new fault sections that meet the criteria of (1) a length ≥7 km, (2) evidence of recurrent Quaternary tectonic activity, and (3) documentation that is publicly available in a peer-reviewed source. The prior CEUS models only included 6 fault sections (sources) and 10 fault-zone polygons (previously called repeating large magnitude earthquake (RLME) polygons). The revised databases include 15 fault sections and 10 fault zone polygons. Updates to the faults constitute a 150% increase in fault sections, but no change in the number of fault-zone polygons, although some fault-zone polygons differ from RLME polygons used in prior models. No faults were removed from past models. Several seismic zones and suspected faults were evaluated but not included in this update due to a lack of information about fault location, geometry, or recurrent Quaternary activity. These updates to the fault sections, fault-zone polygons, and earthquake geology databases will inform fault geometry and activity rates of CEUS sources during the 2023 NSHM implementation.

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Seismological Research Letters Article

Source-reported bounding extent: 25.297267313035647° to 51.85857884546667° latitude; -104.33762311995545° to -66.17641020136095° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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Jessica A. Thompson Jobe, Alexandra Elise Hatem, Ryan D. Gold, Christopher B. DuRoss, Nadine G. Reitman, Richard W. Briggs, Camille Marie Collett. 2022-10-12. Revised earthquake geology inputs for the central and eastern United States and southeast Canada for the 2023 National Seismic Hazard Model. https://doi.org/10.1785/0220220162

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