The Crotone Megalandslide, southern Italy: Architecture, timing and tectonic control.

Large-scale submarine gravitational land movements involving even more than 1,000 m thick sedimentary successions are known as megalandslides. We prove the existence of large-scale gravitational phenomena off the Crotone Basin, a forearc basin located on the Ionian side of Calabria (southern Italy), by seismic, morpho-bathymetric and well data. Our study reveals that the Crotone Megalandslide started moving between Late Zanclean and Early Piacenzian and was triggered by a contractional tectonic event leading to the basin inversion. Seaward gliding of the megalandslide continued until roughly Late Gelasian, and then resumed since Middle Pleistocene with a modest rate. Interestingly, the onshore part of the basin does not show a gravity-driven deformation comparable to that observed in the marine area, and this peculiar evidence allows some speculations on the origin of the megalandslide.