The November 9, 2022, compressional seismic sequence (Mw 5.5)- another piece of information to the 3D seismotectonic fault model of the coastal Marche-Adriatic offshore area (Italy)

The coastal Marche-Adriatic region of eastern-Central Italy has been long questioned in the literature whether being active or not and, in case of activity, whether under a compressional or a strike-slip regime (de Nardis et al., 2022 with references). Our recent paper integrates high-quality seismological data from a local network with longterm geological constraints to build a 3D crust-scale seismotectonic fault model. Late Pliocene-to-Quaternary NE-verging fold-and-thrust structures develops at the hangingwall of the Adriatic Basal Thrust (ABT), a SW-dipping reverse shear zones which penetrate across the entire crust and is seismogenic at upper and lower crust depths. The November 9, 2022 seismic sequence activated one offshore ABT upper crustal splay with pure compressional kinematics. Two major events (Mw 5.5 and 5.2) enucleated within 1 minute, at depths of ~5 km and ~7.5 km, respectively, and ~8 km away in map view. At a depth of a few kilometres, the seismogenic thrust intercepts two deep extraction wells (Pesaro Mare 4 and Bice 1), re-opening the question of triggered and induced seismicity. Geological section, serial hypocentral crosssections, focal mechanisms, and available information from exploration wells are used to build a detailed nonplanar 3D geometric and kinematic fault model of the structures responsible for the sequence and to test its fits with the previously built regional model. Preliminary observations highlight a synchronous activity of the upper crust segment activated by the sequence with that of surrounding multi-depth fault structures, and Coulomb stress scenarios are built for analysing such an aspect.