Abstract. The general “basin and range” aspect of the Apennine relief is generally attributed to the presently active normal fault systems, whose activity throughout the Quaternary is supposed to have created alternating morphological/structural highs and lows. By coupling field geological survey and geophysical investigations, we reconstructed the 3-D geometry of one of the innermost tectonic basins of the central Apennines, the Subequana Valley, bounded to the north-east by an active and seismogenic normal fault. Our analyses revealed that, since the Late Pliocene, the depression experienced a double polarity, half graben-mode nucleation. An early phase, Late Pliocene-Early Pleistocene in age, was led by the ENE-WSW trending and SSE dipping Avezzano-Bussi fault, that determined the formation of an early depocentre towards the N-NW; subsequently, the main fault became the NW-SE trending, SW dipping and presently active normal fault system, that led the formation during the Quaternary of a new fault-related depocentre towards the NE. By considering the available geological information, a similar structural evolution has likely involved three close tectonic basins aligned along the Avezzano-Bussi fault, namely the Fucino basin, the Subequana Valley and the Sulmona basin, and it has been probably experienced by other tectonic basins of the chain. The present work therefore points out that the morpho-tectonic setting of the Apennine chain results from the superposition of deformation events whose “legacy” must be considered in a wider evolutionary perspective. Within this light, our results testify that a simple “basin and range” model – often adopted for morpho-tectonic and kinematic evaluations in active extensional contexts, as in the Apennines – may be actually simplistic, as it could not be applied everywhere, owing to peculiar complexities of the local tectonic histories.
Gori, S., Falcucci, E., Ladina, C., Marzorati, S., and Galadini, F.: Active faulting, 3-D basin architecture and Plio-Quaternary structural evolution of extensional basins: a 4-D perspective on the central Apennine chain evolution, Italy, Solid Earth Discuss., doi:10.5194/se-2016-103, in review, 2016.