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Recommendations for probabilistic seismic hazard analysis : guidance on uncertainty and use of experts

Budnitz, Robert J.

Washington, D.C. : U.S. Nuclear Regulatory Commission, 1997-04, 2v - PDF (400 N87 CR-6372)

v.1. Main report -- v.2. Appendices (combined in pdf) - Probabilistic Seismic Hazard Analysis (PSHA) is a methodology that estimates the likelihood that various levels of earthquake-caused ground motion will be exceeded at a given location in a given future time period. Due to large uncertainties in all the geosciences data and in their modeling, multiple model interpretations are often possible. This leads to disagreement among experts, which in the past has led to disagreement on the selection of ground motion for design at a given site. The Senior Seismic Hazards Analysis Committee (SSHAC) reviewed past studies, including the Lawrence Livermore National Laboratory and the EPRllandmark PSHA studies of the 1980's and examined ways to improve on the present state-of-the-art. The Committee's most important conclusion is that differences in PSHA results are due to procedural rather than technical differences. Thus, in addition to providing a detailed documentation on state-of-the-art elements of a PSHA, this report provides a series of procedural recommendations. The role of experts is analyzed in detail Two entities are formally defined - the Technical Integrator (TI) and the Technical Facilitator Integrator (FI) - to account for the various levels of complexity in the technical issues and different levels of efforts needed in a given study.

Available online: (43 MB)