New structural and seismological evidence and interpretation of a lithospheric scale shear zone at the southern edge of the Ionian subduction system (central-eastern Sicily, Italy).

Geological, gravimetric, and seismological data from the central-eastern Sicily (Italy) provideevidences of a NW-SE oriented shear zone at the southern edge of the Ionian subduction system. Thisstructure consists of a near 100 km long lithospheric-scale structural and seismic boundary. In thenear-surface, it shows Plio-Pleistocene vertical-axis structural rotations, kilometer-scale topographicimprint, progressive wrenching, and large down-faulting. All these features, together with its locationsouth-west of the subduction system, allow us to interpret the shear zone as the upper plate expression ofan abandoned Subduction Transform Edge Propagator fault, working before slab detachment, currentlyreactivated by elastic rebound or mantle upwelling mechanism triggered by slab detachment, to forman incipient transform belt separating compartments characterized by different motion in the moderncontext of Africa-Europe convergence.