• journal_title：Bulletin of the Seismological Society of America
• Contributor：Chris H. Cramer
• Publisher：Seismological Society of America
• Date：2003-
• Format：text/html
• Language：en
• Identifier：10.1785/0120020206
• journal_abbrev：Bulletin of the Seismological Society of America
• issn：0037-1106
• volume：93
• issue：4
• firstpage：1841
• section：Short Notes

When a site-specific probabilistic ground-motion estimate is required, the full site-amplification distribution should be used instead of a single deterministic median value. A probabilistic methodology using site-amplification distributions to modify rock ground-motion attenuation relations into site-specific relations prior to calculating seismic hazard has been developed and applied at two selected sites in the central United States: Memphis, Tennessee, and Paducah, Kentucky. The use of a completely probabilistic approach can make about a 10% difference in ground-motion estimates over simply multiplying a bedrock probabilistic ground motion by a median site-amplification factor at a 1 in 2475 annual probability of exceedance and even larger differences at smaller probabilites of exceedance. The value of this approach is that a probabilistic answer incorporating the uncertainty in our knowledge of site amplification of ground motions can be calculated.