Late Quaternary faulting within the Southern Apennines seismic belt: new data from Mt. Marzano area (Southern Italy)

Abstract

An integrated geomorphological and geophysical investigation was performed in order to reconstruct the Pliocene-Quaternary geomorphologic evolution and recent tectonics of Mt. Marzano massif (Southern Apennines, Italy). The study area belongs to a region of high seismic energy release, the last event being the strong ( M S 6.9) 1980 Irpinia earthquake. Most of the main faults of the area ceased their activity before development of the Late Pliocene age palaeosurfaces, widely spread over the massif. Beginning in the lower part of the Middle Pleistocene, strong extensional tectonics took place in the southern portion of the massif. WNW-trending faults created the Buccino and S.Gregorio Magno depressions, which underwent subsidence until the Holocene, according to abundant morphostructural evidence. During the Late Quaternary, the N150° trending Mt. Valva–Mt. Carpineta fault and the N110-100° trending Mt. Ogna fault, previously sealed by Pliocene palaeosurfaces, also were re-activated. Morphostructural data were integrated with a high-resolution seismic survey across the Piano di Pecore basin, which is dammed by a fault that slipped 70 cm during the 1980 earthquake. This fault produced no more than 50–60 m of throw during Quaternary times, most probably starting from 100 to 150 kyr BP.