The Afen Slide

As scientists have explored the seafloor they have often found evidence of submarine landslides on the continental margins. In many cases the seafloor topography is quite complex, the consequence of multiple sliding events making interpretation of what has happened difficult. On the slope northwest of Shetland there is a small landslide on its own which we hope that by studying it in detail we can contribute to studies of larger, more complex slides.

The Afen Slide is found between 850 and 1100 m water depths, where the slope is only 1-2° but the failed sediments have spilled out upon the floor of the Faroe – Shetland Channel below 1000m. It covers an area of 40 km², which is about half the size of the city of Edinburgh. The slide cuts about 20m into the soft sediments of the West Shetland slope and displaced a volume of   ~ 0.2 km³.  

It is important for us to determine when this slide occurred and what its trigger was. If it had occurred towards the end of the last Ice age when ice-sheets were melting, causing an unloading of the earth’s crust with earthquakes greater than are experienced now; then the risk of a similar event today would be very low. However if it can be shown that it is a recent sliding event then another slide might be expected in the current environmental conditions. We hope by sample the sediments that slid we can understand how strong they were and type of event could have caused the slope to fail. 

David Long
BGS