Marine geology in the region of the Messina Straits,a nd a puzzling tale of faults, earthquakes and tsunamis

The Straits of Messina is one of the most tectonically active areas of the Mediterranean, and has been the site of the destructive 1908 Messina earthquake. In spite of the hazard potential of this marine area, studies based on modern geophysical data are still lacking. A marine multichannel seismic survey was purposely carried out with the aim to outline the fault pattern in the area of the Messina 1908 earthquake, and to better understand its significance within the tectonic frame of the region. Within the Messina Straits, faults have been imaged on the Calabrian side, with a 30 km long NW-trending fault, located at the SW tip of Calabria, that is affecting the sea floor, whereas we did not image any extensional fault plane attributable to the Taormina Fault, on the Sicilian side of the straits. The geodynamic implication is that extension in south-eastern Sicily, on the Ionian side of the Hyblean Plateau, and extension in southern Calabria and Messina Straits belong to two different tectonic systems and, therefore, cannot be mechanically linked. Finally, the damages produced by the1908 ground shaking were aggravated by the effects of a remarkable tsunami, with up to 11 m of run-up height, that followed the earthquake. The origin of the tsunami associated with the 1908 earthquake is not yet fully understood, but geological and geophysical evidences substantially undermine a recent proposal that the 1908 tsunami originated by a large landslide offshore Giardini Naxos.