Broadband NDSHA computations and earthquake ground motion observations for the Italian territory

The aim of this work is two-fold: 1) to compare the results of national scale NDSHA modelling for the Italian region at 10 Hz cut-off, based on the relevant available knowledge, with observations (e.g., peak ground motion values) and existing empirical attenuation relations; 2) to update the scaling law for source spectra (SLSS) to be used for the selected area. The new set of source spectra, defined along the lines suggested by the comparison with empirical attenuation relations, produces acceptable results in terms of PGV and spectral acceleration at long periods. Synthetic PGA and SA at short periods show a faster attenuation with respect to the observed ones and, therefore, the effect of complex attenuation factors should be explored in future ad hoc studies.