Lithospheric double shear zone unveiled by microseismicity in a region of slow deformation.

The deformation style of the continental lithosphere is a relevant issue for geodynamics and seismic hazard perspectives. Here we show the first evidence of two well-distinct low-angle and SW-dipping individual reverse shear zones of the Italian Outer Thrust System in Central Italy. One corresponds to the down-dip prosecution of the Adriatic Basal Thrust with its major splay and the other to a hidden independent structure, illuminated at a depth between 25 and 60 km, for an along-strike extent of ~ 150 km.