Tectonics and crustal structure of the Campania continental margin: relationships with volcanism

The crustal structure of the Campania continental margin is synthesized from outcrop, seismic reflection and gravimetric data. Outcrop and subsurface geological data reveal the presence of NE-SW faults, E-W faults and NW-SE faults. An older extensional event occurred along NW-SE faults and was followed by the main extensional event linked to the activity of NE-SW normal faults. The latter were active between 700 and 400 ka producing half-grabens filled by more than 5 km of Quaternary deposits. The stratigraphic signature of these tectonic events corresponds to a Lower Pleistocene marine unconformity-bounded unit overlain by Middle Pleistocene rocks belonging to a transgressive-regressive cycle. A crustal section of the Campania margin displays an asymmetric linked fault system characterized by a 10-12 km-deep main detachment level, listric normal faults and rollover anticlines. Structural and stratigraphic data document that the inception of volcanic activity at Vesuvius occurred at 400 ka, just after the main extensional event, and the volcano is located at the margin of a rollover anticline.