Mass transport deposits and geo-hazard assessment in the Bradano Foredeep (Southern Apennines, Ionian Sea)

Seafloor bathymetry, combined with multi-scale seismic reflection profiles, were used todescribe the morphostructural setting of the Bradano Foredeep (Gulf of Taranto,northern Ionian Sea), where a submerged portion of the Southern Apennines isfacing the Apulia Platform in the Calabrian Arc convergent margin. In thiscomplex area, marine geophysical data highlight the presence of two mega-slidedeposits at the shelf-slope transition, which are most likely the largest everdescribed in the region. These slid masses, named the Bradano Basento MegaSlide(BBMS) and Bradano Basento MegaSlide 1 (BBMS1), form a Mass Transport DepositComplex (MTDC) affecting and eroding the topmost portion of the outer Apenninesdeformation front and the Apulian Foreland Ramp. It was emplaced in latePleistocene times inside the narrow (about 10 km wide) Bradano Foredeep basin,a Plio- Pleistocene submarine trough developing at the chain front. The youngestof these deposits (BBMS1) likely predates the Last Glacial Maximum. Location ofthe MTDC within the subduction complex suggests that active tectonics andseismic shaking might represent the main triggering mechanisms for gravitativeinstability in this area, although gravitational tectonics and sedimentcreeping mechanisms cannot be excluded. On the other hand, size anddistribution of the MTDC in the sedimentary record of the Bradano Foredeepsuggest the need of re-evaluating the potential for large earthquakes/tsunamis,and more in general geological hazard related to submarine sliding masses,along the coast of this highly populated area.