Indagine su alcuni terremoti con epicentro nell'area Mediterranea

Abstract

The object of this work has been performed to check the reliability of the results obtained for the P„ travel-times arising from western Sicily. For this purpose a careful investigation on 25 earthquakes originating in the Mediterranean area has been developed: the basic parameters used to carry out the check, have been the ones computed by the International Seismological Centre (<pu, ).a, li ± 8h, II ± 811, SI)) previously subjected to a critical examination. For each earthquake iP„, tP,n, and tP„2, of the recording stations (up to A <:: 20°) have been calculated by the traveltimes (with respect to one or two focus depths) previously studied and computed for earthquakes in western Sicily (3). The results have been then classified under A, B, C, and 1) according to a criterion of subdivision in classes of reliability suggested by us in another work (4). A, B, C, and I) have been suitably elaborated in four successive series; both the Table 1 and figure 4 synthetize these results. The investigation supports the reliability of the tP„, tPni, and lPn2, travel-times calculated for the Sicilian earthquakes: these travel-times can satisfactorily be applied to all earthquakes originating in the Mediterranean area and are to be preferred to the travel-times employed for Italy which, however, are to be deemed more suitable for earthquakes whose epicentre is in Italian territory. This investigation also points out that the earthquakes in Mediterranean area generally seein to occur at a greater depth than those in middle and northern Italy.