The methodology and application of probabilistic seismic hazard analysis (PSHA) are briefly reviewed. The technology of PSHA are now widely used throughout the world for developing seismic hazard maps, as well as for determining appropriate site-specific ground motion intensities for the design of major or critical infrastructures including nuclear power plants, high-rise buildings, and long-span bridges.

The essential technology of PSHA will be described and illustrated for engineering purposes. The application of PSHA requires historical data of seismic activities in a given region, supplemented by geological and seismological information (interpreted properly). The result of a PSH analysis yields the annual probabilities of exceedance, or the corresponding average return periods, for a range of significant ground motion intensities at a site. The same procedure can be repeated for a number of sites in a given region from which contours of specified intensities may be developed for mapping the seismic hazard of the region. These contours may then be used for seismic zoning.