View article

We report on a high-resolution Vp, Vp/Vs and Qp model of the southern Tyrrhenian subduction zone, obtained by the inversion of P- and S-wave arrival times and t∗ values from intraslab seismicity. The arcuate shape of the southern Apennines–Calabrian arc-Sicilian Maghrebides is perfectly mirrored by two rather continuous low and high Vp bands lying beneath the belt system at ca. 25 and 100 km, respectively. Between 100 and 300 km, two independent high Vp slabs lie beneath the Neapolitan region and the southern Tyrrhenian Sea, separated by unperturbed mantle. We suggest that the ca. 150 km-wide slab window beneath the southern Apennines opened after a tear occurring within a composite subduction system, formed by the Apulian continental lithosphere and the Ionian oceanic slab. The abrupt slab rupture induced ultrafast southeastward retreat of the Ionian slab, and the 19 cm/yr spreading of the …