2008 United States (Lower 48) Seismic Hazard Long-term Model

Science Center Objects

Seismicity catalogs, gridded seismic hazard curve data, gridded ground motion data, and mapped gridded ground motion values are available for the 2008 National Seismic Hazard Model for the Conterminous U.S.

(1) Seismicity catalogs are available for the western U.S. (in Mw) and central and eastern U.S. (in mb).

(2) Gridded (0.05 degree by 0.05 degree) ground motion values and hazard maps are available for peak ground acceleration (PGA) and 0.1, 0.2, 0.3, 0.5, 1.0, and 2.0 second spectral acceleration (SA) at probability levels of 2% in 50 years (annual probability of 0.000404), 5% in 50 years (annual probability of 0.001026), and 10% in 50 years (annual probability of 0.0021), assuming firm rock soil conditions at 760 m/s, for the conterminous U.S. (US). Additional periods (0.75s, 3s, 4s, and 5s) are available for the western U.S. (WUS). Data was derived from the probabilistic seismic hazard curves.

(3) Gridded (0.1 degree by 0.1 degree) ground motion values and hazard maps are available for peak ground acceleration (PGA) and 0.1, 0.2, 0.3, 0.5, 1.0, and 2.0 second spectral acceleration (SA) at probability levels of 2% in 50 years (annual probability of 0.000404), 5% in 50 years (annual probability of 0.001026), and 10% in 50 years (annual probability of 0.0021), assuming hard rock site conditions at 2,000 m/s, for the central and eastern U.S. (CEUS). Data was derived from the probabilistic seismic hazard curves.

(4) Gridded (0.05 degree by 0.05 degree) ground motion values and hazard maps are available for peak ground acceleration (PGA) and 0.1, 0.2, 0.3, 0.5, 0.75s, 1.0, 2.0, 3.0, 4.0, and 5.0 second spectral acceleration (SA) at probability levels of 2% in 50 years (annual probability of 0.000404), 5% in 50 years (annual probability of 0.001026), and 10% in 50 years (annual probability of 0.0021), for VS30 (time-averaged shear wave velocity in the upper 30 meters of the crust) values of 1,150 m/s, 537 m/s, 360 m/s, 259 m/s, and 180 m/s, for the western U.S. (WUS). Data was derived from the probabilistic seismic hazard curves.

Development of the 2008 National Seismic Hazard Model for the Conterminous U.S. is documented in the USGS Open-File Report 2008-1128.

This dataset is considered a legacy dataset. The original dataset was uploaded to the USGS website at the time of publication of the seismic hazard model (2008) but was later moved over the the USGS ScienceBase Catalog (2019). The original dataset was assumed to be complete and accurate, but may contain inconsistencies when compared to more recent, actively maintained datasets.

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