Eos, Transactions American Geophysical Union

Comparison between probabilistic seismic hazard analysis and flood frequency analysis



Probabilistic seismic hazard analysis (PSHA) was originally developed from the analogous flood or wind problem and was used for risk analysis in a similar way PSHA was extended later to directly incorporate the uncertainty of ground motion. Such direct incorporation of uncertainty has no clear physical basis and makes it difficult to understand, explain, and use PSHA.

These difficulties may result in overly conservative seismic design for safeguarding structures such as buildings, bridges, and nuclear power plants against seismic risk. For example, ground motions with a risk level of 2% probability of exceedance (PE) in 50 years, developed from PSHA [Frankel et al., 1996, 2002],are the basis for national seismic safety regulations and design standards such as the 2000 International Building Code (IBC-2000).