Submarine mass-movements along the slopes of the active Ionian continental margins and their consequences for marine geohazards (Mediterranean Sea)

The Ionian margins of Calabria and Apulia (IMCA) have been affectedby mass movements of varying style, scale and age. Here we present examples ofseabed and subsurface features identified along more than 400 km of the IMCAfrom multibeam seabed imagery and subbottom profiles acquired by OGS since2005. Four different types of mass movement phenomena are recognized withexpression at seabed and in the shallow subsurface: (1) mass transport complexes(MTCs) within intra-slope basins, (2) isolated slide scars (ISS) along open slopes,(3) slope-parallel sediment undulations (SPSU) recording block-rotations linked tofluid migration, and (4) headwall and sidewall scarps (HSC) in submarine canyons.Preliminary analyses of sedimentary processes suggest that both open-slope failurescapable of triggering tsunamis and retrogression of canyon headwallswithin 1–3 kmof the Calabrian coast represent potential geohazards for coastal populations andoffshore infrastructures.