The structure of Mediterranean arcs: New insights from the Calabrian Arc subduction system

•We present the first modern amphibious seismic experiment conducted across Calabria.•The section shows the forearc-to-backarc Vp structure of the subduction system.•We infer mantle exhumation in the Marsili backarc basin, in the Tyrrhenian.•The system is marked by spatially rapid petrological and tectonic changes.•An analog of Tethys subduction systems formed by slab rollback is proposed. The formation of Cenozoic mountain belts in the Mediterranean realm was preceded by tens of millions of years of subduction, forming volcanic arcs, and frontal contractional systems. In addition, subduction usually involves slab rollback and formation of oceanic backarcs. Although such structure must have influenced the orogeny of Mediterranean mountain belts, no active analog has been mapped with modern crustal-scale seismic methods. Here, we study the entire Calabrian subduction system to map the structure resulting from Tethys lithosphere subduction and slab rollback, in a process that must be akin to that operating during a phase of the formation of the Mediterranean orogenic belts. We present a crustal-scale cross section of the entire Calabrian subduction system obtained from on- and off-shore wide-angle seismic data. The 2D P-wave velocity section shows spatially abrupt (