Dynamics, Velocity and Run-Out of the Giant Storegga Slide

A huge slide (volume of 2400 km3 and run-out 450 km) was released in the Storegga area off the western coast of Norway during early Holocene, followed by numerous smaller debris flows. We perform numerical simulations of the giant slide using a Bingham model for the clay material. Agreement with present deposit distribution and run-out is found by assuming that the shear resistance between the debris flow and the seabed decreases during the flow, and we suggest sediment remolding or hydroplaning as possible explanations. Debris velocities are predicted and possible applications to the associated tsunami event are investigated.