Fault Pattern and Seismotectonic Style of the Campania – Lucania 1980 Earthquake (Mw 6.9, Southern Italy): New Multidisciplinary Constraints

New fault trace mapping and structural survey of the active faults outcropping within epicentral area Campania-Lucania 1980 normal earthquake (M w 6.9) are integrated with a revision pre-existing data an updated interpretation CROP-04 near-vertical seismic profile to reconstruct surface depth geometry, kinematics stress tensor seismogenic pattern. Three main alignments, organized in high-angle en-echelon segments several kilometers length, identified characterized. The inner intermediate ones, i.e. Inner Irpinia (InIF) Faults (IF), dip eastward; outer Antithetic Fault (AFA) dips westward. Both InIF IF strike NW-SE along northern central rotate W-E southern for at least 16 km. We provide evidence coseismic faulting (up 1 m) not recognized before E-W document ruptures maximum vertical displacement up ∼1 m where already surveyed from other investigators 40 years ago. Fault/slip new compilation focal mechanisms (1980 – 2018) were used strain analyses show coherent NNE-directed principal over time different crustal depths, crustal-scale deviation classic SW-NE tensional direction across Apennines Italy. continuation is analyzed available hypocentral distributions. Integrating all information, 3D seismotectonic model, extrapolated base layer, built. It outlines graben-like structure bend developed shallower than 10–12 km, hanging wall extensional NE- E-dipping basal detachment. In our interpretation, such configuration implies control transfer during provides second sub-event, occurred 20 s. Our reconstruction suggests that latter ruptured NNE-dipping splay striking segment possibly also antithetic SSW-dipping splay, two in-sequence episodes.