GNGTS 2016 - Atti del 35° Convegno Nazionale

30 GNGTS 2016 S essione A matrice GEOLOGICAL AND GEOPHYSICAL EVIDENCE OF THE PRETARE-PIEDILAMA NORMAL FAULT (ARQUATA DEL TRONTO, CENTRAL ITALY) S. Catalano, S. Grassi, S. Imposa, G. Lombardo, F. Panzera, G. Romagnoli, G. Tortorici Dpt. Biological, Geological and Environmental Sciences, Earth Sciences section, University of Catania, Italy Introduction. We here describe the geological, morphological and geophysical evidence of a Recent normal fault affecting the surroundings of the villages of Pretare and Piedilama, in the Arquata del Tronto territory in the central Apennines. Our data derives from the preliminary geological and geophysical surveys we performed in the frame of the seismic microzonation activities, promoted by the Center for seismic microzonation and its applications on behalf of the National Department of Civil Protection, in the areas that have been struck by the August 24, 2016 Mw 6.0 earthquake. Geological setting. TheArquata del Tronto area is located in a region of the centralApennines characterised by an impressive roughly N-S oriented thrust and fold belt which is dissected by later (Plio-Quaternary) NW-SE oriented extensional features (Pierantoni et al. , 2013). The investigated sectors are located at the footwall of themainN10° trendingmainSibilliniMountains thrust zone that separates the centralApennine mountain front from theMarche-Abruzzi foothills (Pierantoni et al. , 2013). This regional thrust front brings the Late Jurassic-Miocene carbonate succession of the former Adria paleomargin onto the Messinian turbiditic deposits of the Laga Formation (Ricci Lucchi, 1975; Cantalamessa et al. , 1980). The thrust front is associated to roughly N10 trending folds that develop in the region of Arquata del Tronto, along the valley Fig. 1 – Geological map achieved by a detailed field surveys (1:5000 scale) and geophysical investigations carried out in Pretare-Piedilama area. In the legend the Quaternarycontinentaldeposits consists of: MUSa1q landslide deposits (Holocene); MUSb2 eluvio-colluvial deposits (Holocene); MUSbn terraced alluvial deposits (Holocene); MTIa1 paleolandslide deposits (Upper Pleistocene); MTIa paleoslope deposits (Upper Pleistocene). The geological substratumis represented by the pre-evaporitic member of the Laga Formation consisting of three lithofacies associations: pelitic-arenaceous LAG4e, arenaceous-pelitic LAG4b and arenaceous (prevailing) LAG4c.