Accelerometric radiation simulation for the September 26, 1997 Umbria-Marche (Central Italy) main shocks

We applied a hybrid stochastic-deterministic method to simulate the strong ground motion characteristics associated with the September 26, 1997 Umbria-Marche main shocks. One hundred different rupture processes on previously inferred fault planes were simulated. The maps of computed PGA (mean values from 100 simulations) show a SE alignment for the 00:33 event and a NW alignment for the 09:40 event, in accordance with the macroseismic data. Moreover, we found a good agreement between the predicted 1σ interval for the PGA values and the data recorded at several accelerometric stations. As a further test, we computed the response spectra at the station Cerreto di Spoleto and found a satisfactory agreement with the synthetic results.