Modelling rheological transitions within the solid Earth (including the frozen oceans)

Abstract: Earth’s materials, like ice and rocks, are known to exhibit a variety of mechanical behaviors depending on the local temperature, fluid pressure, loading conditions as well as on the time and spatial scales at which they are observed. In the geophysical context of the polar oceans, fault zones and landslides, modelling their deformation therefore constitutes a multi-scale problem that lies between the fields of solid mechanics and fluid dynamics. My main research interest is to solve such problem by developing numerical models for these geophysical systems that are simple but yet able to capture their complex behaviour by representing their different mechanical regimes - granular, brittle, ductile, fluid - and the transitions between these regimes. This presentation will develop on the similarities between the deformation mechanisms present in these different systems and on how these similarities can be exploited to build transversal numerical models. A model that was developed to represent the brittle solid to fluid transition in the Arctic sea ice cover will be presented as well as its adaptation to simulate the brittle to ductile transition in the vicinity of faults and the associated slow earthquake phenomena. A statistical approach for the representation of the transition between a cohesive, brittle solid and a granular media in these systems will also be discussed.