Hassefras, Emiel

Research Project

My research fo­cu­ses on the triggering of sub­mar­ine land­sli­des. Submarine landslides constitute a major hazard to offshore infrastructure and coastal areas, due to their tsunami-generating potential. Hence, it is important to understand how submarine landslides are set in motion.

Many studies have already pointed out that pore pressure plays an important role in failure initiation. Overpressure lowers the she­ar strength of sed­i­ment layers and as a result it causes slope instability. Processes that generate overpressure are sedimentation, seismic shaking, and gas hydrate dissociation. Gas hydrates are ice-like mixtures of methane gas and water that are stable under high pressure and low temperatures. The dissociation of gas hydrates generates water and free gas which leads to excessive pore pressure due to volume expansion. Most frequently, the dissociation of gas hydrates takes place at the base of its stability boundary. At this boundary, the free gas is trapped underneath the impermeable hydrate layer. For the gas to transfer to shallower depths and finally the seafloor, permeable pathways such as fault networks or gas chimneys have to be in place.

Although hydrate dissociation is proposed as a potential trigger by many field studies and conceptual models, it still remains unclear whether excess pore pressure resulting from dissociation can singularly trigger submarine landslides. Therefore, my project aims to relate overpressure to progressive slope failure within the gas hydrate stability zone. The main focus of my research is to quant­it­at­ively determine the role of overpressure, by means of numerical modelling. To that end, I aim to develop a finite element model that couples focussed gas flow and the deformation of a hydrate bearing slope.

Curriculum Vitae