IT Specialist
Geologic Hazards Science Center
Email:
rukstales@usgs.gov
Office Phone:
3032738677
Fax:
3032738600
ORCID:
000000032818078X
Location
1711 Illinois St
P.O. Box 25046
Mail Stop 966
Denver
, CO
802250046
US
Supervisor:
Nicolas Luco

This data set represents the results of calculations of hazard curves for a grid of points with a spacing of 0.05 degrees in latitude and longitude. This particular data set is for horizontal spectral response acceleration for 0.2second period with a 1 percent probability of exceedance in 1 year. The data are for the Western United States and are based on the longterm 2014 National Seismic Hazard Model.

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 georeferenced tiff (GeoTIFF).

These data sets are the results of calculations of hazard curves for a grid of points with a spacing of 0.05 degrees in latitude and longitude. They represent the chance of experiencing potentially damaging ground shaking for fixed ground shaking levels that corresponds with MMI = VII. The values are obtained by averaging the probability of experiencing MMI = VII based on a peak ground acceleration value of 0.2152 g for site class D, and the probability of experiencing MMI = VII based on 1.0second spectral acceleration value of 0.2256 g for site class D. The data are for the Central and Eastern United States.

In processing step 3, declustering is applied to flag aftershocks and foreshocks in catalog wmm.c2. Each earthquake is considered a potential mainshock, and an algorithm searches for events within a specified distance from its epicenter and time after its origin (Gardner and Knopoff, 1974). A smaller earthquake found within a window is an aftershock. If a larger earthquake is found, the first earthquake is a foreshock of the larger one. WUS catalog wmm.c3 is produced by deleting aftershocks and foreshocks from wmm.c2; it consists of statistically independent earthquakes with moment magnitudes greater than or equal to 2.5.

Each of the downloadable files below contains spectral response accelerations at 22 periods on a grid of latitudes and longitudes that cover this geographic region. See the parent item for how RiskTargeted Maximum Considered Earthquake (MCER) spectral response accelerations are derived from the data in these files.

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