UNVEILING FLUID-FAULT INTERACTION IN STRIKE-SLIP REGIMES AND ACTIVE TECTONICS IN HIGH AND LOW STRAIN DOMAINS ALONG THE SOUTH-EASTERN THYRRENIAN MARGIN (CENTRAL MEDITERRANEAN)

This research project investigates deformation processes and fault activity in the Peloritani Mountains and the Aeolian Archipelago (southern Tyrrhenian Sea), with particular attention to the role of fluid circulation in modulating crustal strain release and fault reactivation.The first study combines GNSS position–time series and high-resolution hypocentre relocations to characterize the geometry, kinematics, and temporal evolution of deformation along key strike-slip systems, including the Aeolian–Tindari–Letojanni Fault System (ATLFS) and the Western Aeolian Fault Systems (WAFS). Results reveal the presence of four major right-lateral strike-slip deformation zones and highlight a strong temporal correlation between (i) enhanced gas emissions and volcanic inflation at Vulcano Island, (ii) increased seismic strain release at mid-crustal depths, and (iii) accelerations of the eastern block of the ATLFS. These findings demonstrate that fluids circulating at near-lithostatic pressures significantly weaken fault zones, promoting slip acceleration and sustaining low-magnitude seismicity over several months.The second study focuses on identifying active tectonic structures within the Low Strain Rate region (LSRr) of the Milazzo Gulf and Peloritani Mountains. By adopting a multidisciplinary "land-to-sea" approach that integrates GNSS velocity fields, InSAR data, and offshore seismic reflection profiles, the research reveals a previously unmapped NNW–SSE trending right-lateral strike-slip belt. This system is characterized by offshore positive flower structures and is associated with onshore vertical velocity gradients and fluid escape features, suggesting that overpressurized fluids facilitate fault lubrication and aseismic creep.Overall, this thesis provides new constraints on the interaction between fault mechanics, crustal deformation, and fluid–rock processes in an active convergent margin setting.