Active and capable fault? The case study of Prata D'Ansidonia (L'Aquila, Central Apennine)

Lorenzo Lo Sardo (a), Emanuela Falcucci (b), Stefano Gori (b), Marco Moro (b), Michele Saroli (a), Fabrizio Galadini (b), Giandomenico Fubelli (c), Michele Lancia (a), Giuseppe Pezzo (b), Francesca D'Ajello Caracciolo (b), Michele Di Filippo (d), Maria Di Nezza (b), Iacopo Nicolosi (b) & Stefano Urbini (b)
(a) Department of Civil and Mechanical Engineering, Università di Cassino e del Lazio Meridionale, V. Di Biasio 43, 03043 Cassino, Italy, E-mail: l.losardo@unicas.it (b) Istituto Nazionale di Geofisica e Vulcanologia (INGV), Via di Vigna Murata 605, 00143 Roma, Italy (c) Department of Earth Sciences - Università di Torino, Via Valperga Caluso, 35 - 10125 Torino (d) Department of Earth Sciences , Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185, Rome, Italy.

The study deals with the morphogenetic meaning of several linear scarps that carved the paleo-landsurface of Valle Daria, an extended geomorphological feature located between Barisciano (AQ) and Prata D'Ansidonia (AQ). These villages are situated in the southern termination of the L'Aquila intermontane basin (one of the largest basin of the central Apennines), nearby the epicentral area of the 6th April 2009 earthquake (Mw 6.1). These scarps, up to 3 meters high and up to 1.5 km long, define narrow/elongated flat-bottom depressions, filled by colluvial deposits. These depressions are carved into fluvial-deltaical conglomerates, dated back to the lower Pleistocene. Even if different authors have interpreted these shapes as a paleodrainage or secondary faults, a morphometrical study of the Valle Daria paleo-landsurface provided several information which cast doubt on these two interpretations. In order to better understand the nature and the state of activity of these lineaments, geological, geomorphological and geophysical surveys were carried out. A paleoseismological trench pointed out two events of deformation. The curvilinear shape of the shear plane seems to be related to a slow deformation, attributable to collapse-phenomena. Three GPR profiles, two ERT profiles and two microgravimetrical profiles seem to corroborate this interpretation. Therefore this study permits to attribute the genesis of these scarps to tectono-karstic phenomena, excluding the presence of an active and capable fault.

Active and capable fault, Quaternary geology, paleoseismology, applied geophysics