Geological, seismological and geodetic evidence of active thrusting and folding south of Mt. Etna (eastern Sicily)

Mt. Etna volcano is located in eastern Sicily over the front of the collisional fold and thrust belt, where it is cut by the major Aeolian-Tindari-Malta Escarpment lithospheric boundary (Fig.1, Palano et al., 2012). Accordingly, in the Mt. Etna area two distinct tectonic domains, characterized by compressive and tensional regimes, coexist (Cocina et al., 1997; Monaco et al., 2002). They are separated by a NNW-SSE trending boundary composed of en–echelon normal-dextral faults, roughly extending from the summit craters to the northern suburbs of Catania (Fig. 1a). The eastern sector is characterized by normal-oblique faults, related to WNW-ESE regional extension (Monaco et al., 1997), and flank sliding phenomena (Azzaro et al., 2013). Conversely, in the western sector, south of the volcanic edifice, contractional structures mostly occur. They are represented by a W-E trending fold belt that have deformed Pleistocene foredeep deposits in response of NNW-SSE oriented regional compression (Labaume et al., 1990; Catalano et al., 2011; Ristuccia et al., 2013). According to Lavecchia et al. (2007) this area is part a unique regional-scale, deep crustal seismogenic structure (named Sicilian Basal Thrust) whose focal mechanisms are compatible with a nearly average N–S shortening and with some field evidence of active fold-and thrust deformation at the Sicilian chain front.