Structural complexities and tectonic barriers controlling recent seismic activity in the Pollino area (Calabria–Lucania, southern Italy) – constraints from stress inversion and 3D fault model building

Abstract. We reconstruct the 3D fault model of structures causative 2010–2014 Pollino seismic activity by integrating structural–geological and high-resolution seismological data. constrained at surface with fault-slip data, depth, using distributions selected high-quality relocated hypocenters. Relocations were performed through non-linear Bayloc algorithm, followed double-difference relative location method HypoDD applied to a P-wave velocity model. Geological data highlight an asymmetric active extensional system characterized E- NNE-dipping low-angle detachment, high-angle synthetic splays, SW- WSW-dipping, antithetic faults. Hypocenter clustering time–space evolution seismicity suggest that two sub-parallel WSW-dipping seismogenic sources, Rotonda–Campotenese Morano–Piano di Ruggio faults, are responsible for seismicity. The area patches obtained projecting hypocenters early aftershocks on planes, consistent observed magnitude strongest events (Mw=5.2, Mw=4.3). Since earthquake-scaling relationships provide maximum expected magnitudes Mw=6.4 Mw=6.2 we may suppose that, during sequence, did not entirely release their potential. reconstructed also points out between activated western segment Fault. latter was involved in recent but could have acted as barrier southern propagation limiting dimensions generated earthquakes.