Seismicity and crustal structure in the Italian region: a new review using a synthesis of DSS results and updated catalogues of earthquakes

Abstract

Both historical and instrumental updated catalogues of the earthquakes in the Italian region, are used to compare the location of the epicentres and the focal depth of seismic events with the structure of the Earth crust as determined by the Deep Seismic Soundings (DSS) and according to a published interpretative synthesis. In the past, several attempts were made to do this on the same subject; however, the investigations concerned only some areas of the region, when both the seismic activity and the interpretation of DSS profiles were often based upon inhomogeneous or preliminary data. In this work, we profit from the most recent and complete database of Italian seismicity, to extend the study to the whole peninsula. The comparison confirms that the seismicity occurs more frequently where structural changes are observed by the DSS profiles. The main activity seems to originate in the upper, brittle crust; nevertheless, even the shallow events are particularly concentrated where tectonic features were discovered in the lower crust or at the Moho boundary. The hypocenters tend to deepen where a process of active subduction is occurring. It is believed that the results described herewith could be used as additional elements for the study of seismogenesis.