The seismic phenomena which happened near Cerreto di Spoleto (December 1974) have been studied by data collected from the National Network and the seismic mobile station. The latter had been placed in the epicentral zone. As we could know good hypocentral parameters, we determined travel times for Pg, Sg, Pn and Sn waves. For short travel distances it lias been possible to point out strong azimuthal velocity anomalies, connected with systematic errors in the epicentral determination. This work allows us to foresee the possibility of improving (lie knowledge of the crustal characteristics in our Country, as far as recording techniques will improve.