Submarine landslides are underwater mass movements. They happen when a slope becomes unstable and subsequently fails, which might trigger tsunamis or cable breaks. Due to these impacts, the European Training Network SLATE has been established to advance research into submarine landslides. It aims to better understand the triggering factors, motion and evolution, and geohazard potential. As part of the SLATE network, my PhD project investigates the role of gas and gas hydrate in initiating slope failure, as well as the influence of the slope architecture.
The stability of a slope is determined by the ratio of driving forces (mainly gravity) to resisting forces (shear strength). For a slope to turn from an equilibrium state into a state of failure, either the driving force must be increased, or the shear strength reduced. One way to reduce the shear strength is to increase the pore pressure. This can happen when free gas is present, which might originate from gas hydrate dissociation.
In my project I use numerical modelling to simulate the migration pathways of free gas and investigate whether and where increased pore pressures have the potential to initiate slope failure. Furthermore, I develop new conceptual models to evaluate the influence of the slope architecture, e.g slope angle, slope material, or location of faults.
One example of slope failure and a resulting submarine landslide is the Tuaheni landslide complex offshore New Zealand, which serves as an ideal case study. Gas hydrate has been found there, and the landslide has been thoroughly investigated in recent years, which provides a good data base.