Active folding along a rift-flank: The Catania region case history (SE Sicily)

In this paper a new kinematic and dynamic model on the Recent and active contractional deformation of the Catania region, eastern Sicily, is discussed. The study area represents one of the most seismically active region of the Mediterranean, located at the intersection between the front of the Sicily collision belt and the seismogenic Siculo-Calabrian Rift-Zone. The analysed contractional tectonics form an active triangle zone that originated from the tectonic inversion of a Lower-Middle Pleistocene extensional basin, which was located at the northern edge of the African foreland. The triangle zone consists of two antithetic ENE–WSW oriented thrust-ramps that show evidence of motion during the Holocene and bound a folded belt that involves alluvial deposits as young as 40 ka. These contractional structures represent the final product of the positive tectonic inversion of extensional features located, in the Hyblean Plateau in SE Sicily, along the flank of the active rift zone. The Late Quaternary motions along the inverted structures was accommodated to the west by a major N–S oriented left-lateral fault zone, which separates the active contractional domains from the adjacent sectors of the African margin. As a whole, the Late Quaternary contractional tectonics of SE Sicily have been related to a NW-verging crustal stacking, related to a Mantle intrusion beneath the Hyblean Plateau that developed as effect of the rift-flank deformation. The crustal lineaments, which compose the new kinematic model, represents potentially active seismogenic sources that might be considered in the frame of the seismotectonic picture of the Catania region.