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Deprecated[64242] Earthquake Hazards Program

The 2002 U.S. Geological Survey (USGS) National Seismic Hazard Maps display earthquake ground motions for various probability levels across the United States and are applied in seismic provisions of building codes, insurance rate structures, risk assessments, and other public policy. This update of the maps incorporates new findings on earthquake ground shaking, faults, seismicity, and geodesy. The resulting maps are derived from seismic hazard curves calculated on a grid of sites across the United States that describe the frequency of exceeding a set of ground motions.
For background, please see the Parent Item. The Maximum Considered Earthquake Geometric Mean (MCEG) peak ground acceleration (PGA) values of the 2009 NEHRP Recommended Seismic Provisions and the 2010 ASCE/SEI 7 Standard are calculated from the data in the downloadable files below, via the following equations: PGA = min[ PGAUH , max( PGAD84th , 0.6 ) ] for the 2009 NEHRP Recommended Seismic Provisions; PGA = min[ PGAUH , max( PGAD84th , 0.5 ) ] for the 2010 ASCE/SEI 7 Standard; where PGAUH = uniform-hazard peak ground acceleration; PGAD84th = 84th-percentile peak ground acceleration; and 0.6 or 0.5 = deterministic lower limit peak ground acceleration. These peak ground...
Categories: Data
A comparison of the 2017 USGS South America seismic hazard model with the Global Seismic Hazard Assessment Program (GSHAP) model and the 2010 USGS preliminary model was made to see how the models differ. The comparisons were made as ratios of PGA at 10% probability of exceedance in 50 years. Ratio maps of each comparison are included as a geo-referenced tiff (GeoTIFF).
The U.S. Geological Survey (USGS) national seismic hazard models (NSHM) consider two kinds of earthquake sources. Specific faults are modeled where possible. Where faults cannot be identified or characterized, alternative sources can be developed from seismicity catalogs. In a paper submitted to Seismological Research Letters ("Related External Resources", below), we describe a methodology that has been developed at the USGS for making earthquake catalogs for seismic hazard analysis. In this data release we provide the catalogs for the conterminous U.S. that accompany the SRL article. A new catalog is assembled from several preexisting catalogs. Moment magnitudes and related parameters for modeling seismicity...
Earthquake Hazards Program Data Sources includes the ANSS
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