Reconstructing Quaternary Fault System Geometry and Kinematics in the Campania–Lucania Apennines: a comprehensive perspective

The Campania-Lucania Apennines represent one of the most structurally complex sectors of the Apennines, characterized by composite stratigraphy, recurrent seismicity, and significant tectonic activity. Historical and instrumental earthquakes, including the 1980 Irpinia event (Mw 6.9), highlight the region’s active deformation. Previous studies attribute much of this seismicity to extensional tectonics associated with Pleistocene-Holocene normal faults, dipping both eastward and westward, which have contributed to the formation of NW-SE-oriented continental basins.
This work investigates whether the extensional deformation pattern observed in the northeastern Alburni Mts – dominated by east-dipping normal faults splaying upward from a regional synthetic detachment plane – extends across the broader internal sector of the Campania-Lucania arc, from the Sele Plain to Agri Valley. To address this issue, we integrate geological and geophysical datasets to reconstruct the trajectory and kinematics of the extensional faults and the subsurface geometry of the associated syntectonic basins.
The present study relies on a multidisciplinary approach. Field surveys and reprocessed published seismic data were combined to produce a regional-scale geological–structural map covering ~9,000 km², from the southern Picentini Mts to the northwestern slopes of Mt. Pollino. These surface constraints supported the construction of four shallow geological cross-sections.
The subsurface interpretation followed a structured workflow that included calibration – throughout synthetic seismogram generation using available well sonic logs in the study area – of seismic data interpreted on twelve commercial 2D seismic lines provided by Eni S.p.A (Italian energy company) and additional seismic profiles from the ViDEPI database, incorporated after being digitized from pdf format into SEG-Y to ensure compatibility and consistent quality of interpreted grids. Seismic interpretation employed multiple techniques, including literature analysis and the digitization of vintage seismic profiles, through raster-to-SEG-Y conversion, for subsequent processing in Move® and Kingdom® platforms, enabling methodological refinement through cross-comparison for this highly complex region.
Depth conversion of the resulted seismic interpretation from two-way travel time to depth, advanced the generation of crustal-scale model. This allowed comparison of contractional and extensional structures and supported 2D restoration analyses to quantify the elongation associated to Quaternary extension, along transects. The resulting 3D model, built from depth-converted  seismic transects down to the Apulian Platform roof, reveals key structural features as: i) the geometry of extensional fault systems and the depth to detachment, ii) hierarchical relationships between normal and reverse faults, and iii) the morphology of Quaternary syntectonic basins with their sedimentary infill. These findings contribute to a comprehensive 3D representation of active extensional faults in the southern Apennines, developed within the framework of the MUSE 4D PRIN project.
This integrated approach demonstrates the value of combining geological field observations with seismic interpretation and well data to constrain fault architecture and basin evolution in highly complex tectonic settings. The results provide new insights into the structural framework of the Campania-Lucania Apennines, with implications for seismic hazard assessment and geodynamic models of the southern Apennines.