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