GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 1.1 GNGTS 2023 3-D imaging strategies as an essential tool to investigate Quaternary tectonic basin internal structure and evolution. New insights from a 3-D deep electrical resistivity survey in the Campo Felice basin (central Italy) V. Sapia 1 , F. Villani 1 , F. Fischanger 2 , M. Lupi 3 , V. Romano 4 , P.M. De Martini 1 , L. Ruggiero 1 , A. Sciarra 1 , P. Baccheschi 1 , V. Materni 1 , S. Maraio 1 , A. Smedile 1 , M. Pischiutta 1 , M. Rossi 4 , R. Civico 1 , T. Ricci 1 , G. Di Giulio 1 , M. Vassallo 1 , C.A. Brunori 1 , L. Improta 1 1 Istituto Nazionale di Geofisica e Vulcanologia, Roma, Italia 2 Geostudi Astier S.r.l., Livorno, Italia 3 University of Geneva, Geneva, Switzerland 4 Università degli Studi di Roma La Sapienza, Roma, Italia We provide the first 3-D electrical resistivity model of the Campo Felice basin (CFB), a Quaternary tectonic intermontane depression, set in the hanging wall of a segmented NW-trending normal faults system, about 30 km long (L’Aquila-Ovindoli-Celano fault system; Salvi et al., 2003) with well documented Holocene activity (Pantosti et al., 1996; Goodall et al., 2021). CFB is bounded to the north by two left-stepping and NW-striking normal faults, named Monte Cefalone (MCF) and Monte Orsello (MOF) faults, where previous studies indicate high seismic potential for M6+ earthquakes (e.g. Benedetti et al., 2013; Schirripa-Spagnolo et al., 2021). The basin is about 10 km long in the NW-SE direction and about 2 km wide. It is filled by alluvial, lacustrine, and glacial deposits from the Middle Pleistocene to Holocene in age (Giraudi & Giaccio, 2017). To the south, massive moraine deposits (ranging in age from the late Middle Pleistocene to the Last Glacial Maximum, LGM) covering the Cretaceous-Miocene limestone substratum give way to a flat-bottomed area that hosts thick older lacustrine sequences (Giraudi et al., 2011). The subsurface structure of the basin and the geometry of the two bounding faults at depth are unknown. Consequently, reconstructions of the basin tectonic evolution published so far rely only on surface geological and structural data, integrated by nine scientific drillings (< 120 m depth) located in the southern portion of the basin. To fill this gap, during 2020 an INGV team performed cross-disciplinary geophysical 2-D surveys in the central part of the basin (Villani et al. 2023), combining high-resolution seismic profiling with Electrical Resistivity Tomography (ERT). Results show remarkable 3-D heterogeneities, suggesting an asymmetric half-graben basin structure filled