GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 1.1 - POSTER GNGTS 2023 left-lateral shear zones documented in the northern Calabrian Arc. At the culmination of anticlines related to the deep transpressional faults, shallow (<3 km) high-angle normal faults offset the younger deposits (CDPs 1-500, 3500-4000, Fig. 1c). Some of the faults propagate upwards reaching the seafloor and forming well-developed seabed scarps. These morphological features indicate the recent fault activity. The orientation of the shallow normal faults is parallel to the elongated axis of the ridges (Fig. 2b). Based on their depth and direction, we interpret these faults as secondary structures due to tensional stress that occurred in the extrados of the anticlines associated with the transpressional structures. Our findings are supported by seismological data. The earthquake location highlights several alignments that reveal active structures affecting the Ionian offshore, oriented around NW-SE (Fig. 3). Events are mainly located in the northern sector of the Squillace Basin, with a depth range between 0 and 30 km. Focal mechanisms of earthquakes with M> 3 indicate mainly strike-slip or transpressive movements.