Record-based validations of site-specific probabilistic seismic hazard assessment

Abstract

Among the different approaches available to account for site specific ground response in a probabilistic seismic hazard analysis, PSHA, we have explored, with the support of instrumental data, a fully probabilistic method. In it, a probabilistic spectral site amplification function is convolved with a PSHA estimate of a spectral ordinate on rock, to obtain the corresponding spectral ordinate at the site surface. Relying on the abundant records available from the Japanese Kik-net, both at surface and downhole locations, we focused on two stations (NIGH11 and KMMH16), and derived estimations of annual mean rates of exceedance at the surface level, starting from both recorded and simulated accelerations. The simulated surface ground motions were obtained from one-dimensional, linear and non-linear wave propagation analyses, with randomized variabilities on soil stratigraphy. Two methods have been revised and checked for the computation of the convolution integral between the PSHA estimate on rock and a measure of soil amplification.