Application of ground shaking scenarios to PSHA and risk assessment in near field

The study illustrates probabilistic ground shaking hazard analyses and risk assessment in the near field of a rupturing earthquake fault, where the datasets underlying most ground motion predictive equations (GMPEs) tend to provide insufficient coverage. In order to overcome this limitation, explicit modeling of source and wave propagation at the sites of interest can be used. 3D deterministic simulations (limited to frequencies < 2 Hz) are performed, using the spectral element code GEOELSE, and integrated with an appropriate high frequency contribution generated with a stochastic finite-fault model (EXSIM code). We show how the resulting broadband time histories of ground motion can be introduced in PSHA, as an alternative input to the GMPEs, and we compare the derived seismic hazard curves with the results of the traditional approach. The capabilities of the CRISIS2008 code are exploited for this purpose. In seismic risk analysis, the simulated time histories and associated response spectra are treated as realizations of a random variable that represents ground motion and depends on the uncertain fault parameters, in order to evaluate probable damage of classes of buildings through Monte-Carlo approximation. An application to the seismically active area of Sulmona town, in Central Italy, is illustrated.