Fault reactivations and fluids: GNSS and seismological analysis in the Peloritani-Aeolian System

Abstract

Fluids modify the mechanical properties of rocks, such as shear strength and strain behaviour. We analyze the timing of deformation and the occurrence of seismicity during 2021 along strike-slip fault systems in the Peloritani Mountains (northeastern Sicily) and the Aeolian Archipelago, using GNSS and seismic data. Results reveal crustal-scale deformation along a NNW-SSE trending right-lateral transtensional zone across the Peloritani Mts and its offshore prolongation (here defined as the Gulf of Patti-Tindari-Letojanni Fault System, GPTLFS), as well as in WNW-ESE to NW-SE right-lateral transfer zones in the western and central sectors of the Aeolian Archipelago. In 2021, the eastern sector of the GPTLFS showed an increased deformation rate compared to its western part. This deformation episode coincided temporally with an increased release of seismic strain and the unrest at Vulcano. The latter was characterized by rapid ground inflation and enhanced gas emissions. The temporal correlation between these phenomena suggests that enhanced fluid circulation, evidenced by gas emissions in the Peloritani Mts, may modulate the mechanical response of faults, promoting strain release. These observations improve our understanding of the interactions between tectonic deformation, fluids, and volcanic activity in the region.