2014 Preliminary Hazard Maps
This page provides documentation in support of the 2014 update to the National Seismic Hazard Map (NSHM). Note: These preliminary results are being made available for public comment until mid-July 2013, after which the maps and documentation will be finalized, based on further review and consideration of any feedback received.
Please contact the NSHM group with any comments by clicking on the Contact Us link in the footer.
Summary of changes:
(see report for details; hazard implications documented in ‘Results’ at bottom)
Central and Eastern U.S. (CEUS) Sources:
- Revised earthquake catalog, considering parameters from the CEUS-SSC, shac level 3 study.
- Updated maximum magnitude (Mmax).
- Included new tectonic donation models for background sources.
- Considered alternate smoothing algorithms (adaptive and fixed-distance).
- Updated fault source geometry and included new CEUS-SSC fault sources.
- Incorporated new assessment of induced earthquakes.
Western U.S. Sources (except CA):
- Considered Basin and Range Province Earthquake Working Group (BRPEWG) recommendations.
- Updated earthquake catalog.
- Increased maximum magnitude (Mmax) to 8.0.
- Updated dip uncertainty and associated slip rates on normal faults.
- Considered new M-area relations.
- Updated fault source geometries and considered new geodetic slip rates.
- New models for Cascadia earthquake rupture geometries and rates considering recent turbidite studies.
- Updated deep (intraslab) seismicity model in OR and WA.
California Sources (UCERF3):
- Updated fault models.
- New geodetic deformation (slip-rate) models.
- Objectively inverted for rupture rates using all available data.
- Included multi-fault ruptures.
- Developed new smoothed seismicity model.
Ground motion models (GMPEs):
- Reassessed GMPE’s for shallow crustal and subduction sources.
- Implemented new NGAW2 and other GMPEs for Western US.
- Updated epistemic uncertainty model.
- Updated ground motion prediction equations weights.
- Hazard changes in WUS and Cascadia (PDF).
- Hazard changes in CEUS (PDF).
- Hazard implications of UCERF3 model in CA (PDF).