A transitional volume beneath the Sannio-Irpinia border region (southern Apennines): Different tectonic styles at different depths

摘要: Abstract In this paper we investigate the border between Sannio and Irpinia seismogenic regions, a sector of southern Apennine chain considered among most active seismic areas Italian peninsula, to shed further light on its complex seismotectonic setting. We integrated recent seismicity with literature data. A detailed analysis that occurred in 2013–2016 time interval was performed. The events were relocated, after manual re-picking, using different approaches. To retrieve information about stress field area, inversion Fault Plane Solutions also carried out. Hypocentral distribution relocated (ML ≤ 3.5), whose depth is included 5 25 km deepest ones located NW study shows pattern northern one. computed can be grouped three ranges:  18 km, dominated by strike-slip kinematics. Stress across whole area are dealing an heterogeneous set data, apparently governed distinct fields. built upper crustal model profile through integration geological well logs tomographic profiles. Our results suggest co-existence tectonic styles at depths: crust seems affected mostly normal faulting, whereas faulting prevails intermediate lower crust. infer existence transitional volume, 12 18 km depth, acting as vertical transfer zone.