Paper Number: keynote SEISMIC HAZARD ASSESSMENT: PROBLEMS WITH CURRENT PRACTICE AND FUTURE DEVELOPMENTS

This paper addresses issues with current practice in seismic hazard analysis and gives some recommendations for improvements. A review of probabilistic and deterministic approaches is given. The remainder of the paper is focused on PSHA. There continue to be hazard studies that do not properly treat the ground motion variability, leading to systematic underestimations of the hazard. Next, some of the short-comings in current PSHA practice that can be improved without major revisions to the overall methodology are discussed. These include selecting the bin size for the deaggregation, use of Uniform Hazard Spectra, estimation of scenario spectra, estimation of epistemic uncertainty, degree of spatial smoothing of seismicity, and the use of a strict lower bound magnitude. Finally, the future directions of PHSA are addressed. These include incorporating site-specific site response into PSHA and taking project specific structure response into account in conducting PHSA. 1