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Studying faults capable of releasing moderate-to-strong earthquakes is fundamental for seismic hazard studies, especially in a territory that was subject to the strongest peninsular Italy earthquake (1857, Mw 7.1) and hosting the largest European oil field on-land. Fieldwork-based observations in the Campania-Lucania area highlight a SSW-dipping ~ 65 km-long normal-oblique-segmented fault, showing evidence of recent activity and possibly responsible for the 1857 earthquake. It crosses the Maddalena ridge, linking separate Quaternary basins. Two seismic reflection profiles cross the fault trace where it is buried beneath the Val d'Agri Quaternary deposits. Similarities between fault-controlled small basins in the highest portion of the massifs in the study area and the neighboring 1980 Irpinia area (1980 earthquake, Mw 6.9) are interpreted as evidence of trans-ridge fault activity. Kinematic analyses and the stress field inversion provide a N032-trending near-horizontal s3-axis, the same computed in literature for the Irpinia area, highlighting a deviation from the ~N045-axis which characterizes most of the Apennines. This study demonstrates how detailed fieldwork, supported by geophysics and innovative data analysis techniques, can unravel unknown faults while giving a novel interpretation of the trans-ridge faults' style in controlling strong earthquakes, moving away from classical interpretations, and providing a helpful approach in similar contexts worldwide. [ABSTRACT FROM AUTHOR]

This paper sheds light on the structural architecture and tectonic evolution of the Campania-Lucania segment of the Southern Apennines orogen through an integrated analysis of mostly unpublished and partly published (CROP-04 line) seismic reflection profiles, exploratory well logs and geologic-structural relations among the lithostratigraphic units of this region. The pre-orogenic Mesozoic-Neogene carbonate platform, margin-slope and basinal units that compose the upper orogenic level (Apennines fold and thrust belt) were detached from their basement during Miocene thrusting and form a heterogenous multilayer that was thrust above the Apulian foreland platform. The Apulian Platform itself was involved in Pliocene thick-skinned thrusting that controlled the style and localization of Quaternary transtension and extension. The velocity data from sonic logs, the well stratigraphy, and the seismic reflection facies were integrated through an accurate well-to-seismic tie, allowing the building of a specific velocity model for the time-to-depth conversion. We identified different seismic units with distinctive reflections attributes, which were assigned to the lithostratigraphic units logged in the wells. Our analysis documents the stratigraphic-structural arrangement of the thin-skinned thrusts sheets (Liguride Basin, Apennine Platform and Lagonegro-Molise Basin units) that form the Apennines fold and thrust belt. These units show strong lateral thickness changes because of both the original depositional environments and the non-coaxial deformation stages. In contrast, the underlying Apulian Platform is characterized by a regional anticlinorium (∼30–50 km wavelength) that, based on our new reconstruction, extends further west than hitherto known. The anticlinorium exhibits shorter-wavelength (<10 km) anticlines limited by N- to NE-verging thrust ramps, whose high dip (∼45°) suggests they root in the crystalline basement. Our work provides a sound link between surface and subsurface structural setting and an improvement of the geometry of the Apulian Platform, with important implications for structural and seismotectonic models of the region. • Seismic reflection profiles unravel the deep structure of the Southern Apennines. • Integrated use of seismic profiles, well data and geological maps. • Evolution from thin- to thick-skinned shortening. • Orogenic structure controlled by Meso-Cenozoic mechanical stratigraphy. [ABSTRACT FROM AUTHOR]

The Mt. Vettore area is located in the Central Apennines (Italy), a region characterized by intense seismic activity that has recorded multiple moderate-to-high magnitude seismic sequences. The seismic activity is due to the presence of normal fault systems, among which is the Mt. Vettore Fault System (VFS), which was last activated during the 2016-17 Central Italy seismic sequence.. Moreover, the region has experienced three major tectonic phases over geological history, thus it is important to unravel their contribution to the current fracture network. Based on the integration of field observation with Unmanned Aerial Vehicle - Digital Photogrammetry data, we aim to analyze the fracture network on eight different outcrops located at different structural positions with respect to VFZ. Results show that the Late Miocene−Early Pliocene compressional phase deeply affected the present-day fracture pattern, which is especially related to the evolution of the Mt. Sibillini regional thrust and its related anticline. The present-day Quaternary extensional phase, and the associated normal faults, mostly reactivate some of the pre-existing fracture sets. • Definition of the main fracture sets in the Jurassic Calcare Massiccio formation in the Mt. Vettore Area. • Definition of the fracture intensity variation in different structural position along the study area. • Definition of the cross cutting relation between the main fracture sets. [ABSTRACT FROM AUTHOR]