Characterizing Low-to-Moderate Magnitude Earthquake Sequences and Seismic Sources Along the Africa–Eurasia Plate Boundary in Southern Italy

The Africa–Eurasia plate boundary extends along the southern Tyrrhenian Sea in the Sicilian offshore, representing a tectonically complex region mainly characterized by compressional to transpressional regime. Deformation is unevenly distributed along the margin, and seismicity is predominantly characterized by low-to-moderate magnitude earthquakes. The large offshore extent of the area, combined with locally unfavorable seismic network geometry, often limits the resolution of traditional seismological analyses and hampers robust seismic source characterization. In this study, we present an integrated analysis of recent seismicity along the southern Italy segment of the Africa–Eurasia plate boundary, aimed at improving the characterization of active seismic sources and their kinematics through advanced, multi-method seismological approaches. Our investigation includes (i) a regional-scale clustering analysis of earthquakes recorded between 2010 and 2025, and (ii) a detailed characterization of a recent offshore seismic sequence in the southeastern Tyrrhenian Sea. At the regional scale, we apply a density-based spatial clustering algorithm using a space–time distance metric to a high-resolution relocated earthquake catalog. Seismic clusters are subsequently classified as swarm-type or mainshock–aftershock sequences using statistical descriptors of the seismic moment distribution over time. This analysis allows us to identify spatial variations in seismic release patterns and to infer differences in fault segmentation, loading conditions, and stress transfer along the plate boundary. At the local scale, we focus on a Mw 4.7 offshore earthquake sequence and propose an integrated workflow specifically designed to enhance seismic source characterization in offshore environments. The methodology combines Bayesian absolute hypocenter location, machine-learning-based phase picking and event detection, distance geometry solvers for relative relocation, and probabilistic moment tensor inversion. This approach resolves source geometry, fault orientation, and slip kinematics despite non-optimal network conditions, providing robust constraints on active fault planes. Overall, our results demonstrate that advanced, integrated seismological methods significantly improve the characterization of active seismic sources along the Africa–Eurasia plate boundary, offering new insights into fault behavior and deformation processes in offshore and structurally complex regions.