The last phase of the Storegga Slide: simulation of retrogressive slide dynamics and comparison with slide-scar morphology

The prehistoric Storegga Slide, one of the world largest known submarine slides, took place about 8200 years ago. Most likely, the slide was triggered by an earthquake in a steeper slope area in the distal part of the slide. The present-day's morphology of the slide area indicates that major parts of the slide took place as a sequential failure process spreading successively from the far end to the present shelf edge. Numerical simulations illustrating this retrogressive, back-stepping behaviour are presented for the last phase of the Storegga Slide as it reached today's upper headwall. The applied rheological model is based on a Bingham fluid with a history dependent yield strength and consistency.