Recent and active tectonics in the Calabrian arc (Southern Italy)

Abstract

Normal faulting which has developed since the Middle Pleistocene, with an overall ESE-WNW extension, is the dominant mode of deformation which has characterized the Calabrian arc up to the present. Quaternary normal faults extend for a total length of about 180 km along the inner side of the arc. The different normal fault segments, which, during the Pleistocene, controlled the evolution of the main marine sedimentary basins, are varying in length from 10 to 20 km and have fault escarpments showing a very young morphology which define the fronts of the major mountain ranges of the arc. The morphological features of the fault escarpments suggest slip rates of 0.8-1.1 mm/yr for the last 700 k.y. and values of 0.6-0.9 mm/yr for the last 120 k.y., indicating a uniform rate of faulting since the Middle Pleistocene. Crustal seismicity and the mesoseismic areas of historical large events (6.5 ⩽ M ⩽ 7.1) which occurred in the Calabrian arc are located within a narrow belt along the hanging walls of the Quaternary normal fault segments. This suggests that the normal faults which dissect the inner side of the Calabrian arc may be seismically active.