Seismic velocity profiles have been obtained at selected sites of Fabriano, representative of the main geological lithotypes, and the mostly damaged by the September 26, 1997 earthquakes: Borgo, Regina Margherita gardens and Serraloggia.
FTAN analysis has been applied to Rayleigh waves, artificially generated, and the dispersion curves of group velocities have been inverted with the non—linear inversion Hedgehog method. Moreover, the phase velocities, determined by computing the synthetic dispersion curves corresponding to the solution sets of the inversion, have been compared with the SASW dispersion curve, and discrepancies have been found.
Shear wave velocities lower than 300 m/s have been measured at depths lower than 10 mand higher than 800 m/s in the Gessoso-Solfifera formation at Borgo. One-dimensional spectral amplifications have been computed and a correspondence has been found with the maximum peaks of some events recorded by SSN stations in October.