Rayleigh wave phase velocities and upper mantle structure in the Apennines

The dispersion of the phase velocities of the surface Rayleigh waves on the path between the station pair Torino-L'Aquila in the Apennines has been observed with long period seismic stations for twin earthquakes. The inversion was provided by the "Hedgehog" program of non-linear inversion analysis. The interpretation supports the notion that in the Apennines low-velocity material in the mantle is found within a few km of the Moho and may lie immediately below the Moho; however the alternative model of a highvelocity lid and very low-velocity channel cannot be completely rejected.