Crustal structure and deformation across a mature slab tear zone: the case of southern Tyrrhenian subduction (Italy)

Abstract

We compute S velocity profiles of the crust across the Messina Strait (Italy), the tear zone at the southern end of the Ionian subduction zone. Separating Sicily from Calabria, the Messina Strait hosted some of the strongest earthquakes to ever occur in Italy. Here the motion of the Ionian slab with respect to Sicily creates a complex tectonic setting characterized by lithospheric tearing. We show velocity models of the crust, computed from teleseismic receiver function inversion, outlining the differences between Sicily and Calabria. Strong deformation across the Messina Strait between 10–15 and 30 km depth is expressed by strong anisotropy (up to 10%), developed in a ductile shear zone of the crust. The top of these ductile weaker layers could limit the depth extent of future ruptures.