Evidence for seismogenic thrust-related deformation in Sicily

In this paper, we reconstruct the isobaths of the basal thrust plane of the southward-verging Sicilian fold-and-thrust belt, that emerges along the Sciacca-Gela-Catania front and deepens northward reaching a depth of about 30 km beneath northern Sicily. We also compile an updated integrated seismological data set (217 B.C. to 2005 A.D.), define the geometry of the active and seismogenic deformation field from focal mechanisms and analyse the surface and deep distribution of the seismicity. Based on the integration of geological and seismological data, we subdivide the Sicilian region above the thrust plane in two seismogenic provinces, both undergoing active and seismogenic compression. The southern zone corresponds to the surface projection of the upper crust segment (depth 0-10 km) of the basal thrust plane; the mainland zone represents the surface projection of deeper portion of the thrust plane (10 to 30 km). Historical and instrumental earthquakes of low-to-moderate magnitude (M aw<5.5) can be associated to both zones. Rare higher magnitude earthquakes, up to Maw=6.0, have occurred in the mainland zone.