A Zoneless Approach for Probabilistic Seismic Hazard Analysis

-Conventional Probabilistic Seismic Hazard Analysis(PSHA) is difficult to apply in regions lacking sufficient information of the geological setting,active faults,and so forth.Also,for a site-specific PSHA,site effects arising from both crustal rock and overlying soil sediments are generally not assessed rigorously.This is of particular importance for those metropolitan cities having a significant proportion of reclaimed land,because the site-to-site variability of such site effects can be very large.The objective of this paper is to demonstrate an alternative procedure for constructing site-specific uniform hazard response spectra(UHS),extended from a recently-developed Direct Amplitude-Based(DAB) approach.The method has a number of important advantages compared with conventional PSHA.Using the proposed approach,response spectral values have been computed for the whole period range of engineering interest,to form a set of site-specific UHS.