Influenza dell’assetto strutturale nello sviluppo dei fenomeni gavitativi. Un caso di studio in Calabria Settentrionale

Influence of structural setting in the development of the gravity-related phenomena. A study case in Northern Calabria (Italy)

Abstract

Structural and geomorphological studies have been carried out on the Jonian sector of northern Calabria, in the area surrounding the village of Plàtaci (CS). In the study area, located in an intensely tectonically deformed zone, torbidite successions belonging to T. Saraceno Formation and to Albidona Formation crop out. Structural surveys, carried out at both macroscopic and mesoscopic scale, allowed recognition of several sets of discontinuities, related to different events of deformation: 1) NE-vergence thrust surfaces, related to the building-up of the Apenninic Chain in Miocene time; 2) Middle-Pleistocene left strike-slip faults (trending WNW-ESE) and associated NW-vergence transpressive thrust surfaces; 3) Quaternary subvertical normal faults (trending from N-S to NE-SW). The examined area is intensely affected by the development of erosional and gravitational phenomena; the study has been focused on the large-scale landslide affecting the slope where Plàtaci is located. Structural setting had a major role in predisposing conditions favourable to the Plàtaci landslide. It in fact corresponds to an important structural element (duplex), an intensely deformed sector bounded by two main thrust ramps, both at its bottom and top. Just south of the duplex, a deep «wedge», bounded by a normally reactivated thrust fault, on one side, and by an antithetic neoformational normal fault, on the other, has been recognized. Finally, some considerations about the slope movement hazard at Plàtaci, deriving from elaboration and comparison of the previously collected data, are presented.