Some seismological features from an analysis of the recent seismic activity in the Messina Strait

Abstract

abstract An analysis of the recent seismic activity at the Strait of Messina during the last 30 yr, made on the basis of collected observation data, is reported. For about 2 yr this activity has been better observed since a short-period seismic network [Messina Strait Network (MSN)] has been installed on both sides of the strait. The use of a compatible crustal model and of the HYPOSTRE program, elaborated to determine the hypocentral parameters of local events, gives results which can be correlated with the structural characteristics of the graben of the strait. Besides, some elements arising from a previous seismological analysis, made in the same area before the MSN had been activated, are confirmed. In particular, the existence of a microearthquake source, having its epicenter situated a little south of Messina, is here reproposed. Furthermore, the increase in the number of stations on both sides of the reveals that the absorption of the seismic energy propagating parallel to the graben structures is different from that observed when the energy travels orthogonally to them. This fact, together with the results obtained using HYPOSTRE for calculating the focal depth of some local events, suggest the existence of an “energy trap” affecting the more superficial crustal layers. This is correlated with the existence of the dynamic discontinuity of the strait.