Morphological controls on submarine slab failures

An understanding of submarine mass movements is of great importance to the hydrocarbon industry due to the risk they pose to sea floor infrastructure. Technological developments in deepwater surveying methods have produced datasets of the sea floor that rival the best terrestrial ones; however, the study of submarine mass movements remains poorly-developed. Multivariate statistical analysis has a well-established track record for producing quantitative estimates of associated risk for terrestrial landslides and given the often homogenous nature of sea floor sediments, a morphological control on mass movements seems viable. In this study, we perform a statistical analysis on an inventory of shallow slab slides in the West Nile Delta to identify morphometric controls on failure. We find that slopes with planar plan curvature and slope angles <6° account for approximately 95 % of observed landslides and that, beyond this, increasing plan concavity stabilises submarine slopes. This presents a foundation to ultimately reconcile geomorphological observation with geotechnical modelling, and provide additional insight on the controls on submarine instability.