Mechanical modelling of the source of glacial earthquakes in polar regions

Estimating the mass balance of the polar ice caps is a current challenge to understand the rapid evolution of these ice masses under the effect of climate change. The calving of icebergs represents a significant part of the mass loss of Greenland's glaciers. Their overturning near the terminus destabilises the glaciers. Using a reference model in fluid dynamics, we quantified and characterised the interaction between water and a capsizing iceberg, and validated and improved a simplified iceberg overturning model. Then we built and validated a finite element model that reproduces the response of a glacier to the contact force of a capsizing iceberg at the terminus and that includes several rheologies of the glacier/rock interface and an elasto-viscoplastic behaviour law of the ice. Using this comprehensive model, we reproduced surface displacements and stresses at the base of the glacier and analysed the influence of the parameters on the glacier response. We first modelled a glacier with an idealised geometry. Then we modelled a real glacier, the Helheim glacier, and for this we adjusted the model parameters using results from a reference glacier flow model. A strong dependence of the amplitude of the surface displacements on the Young's modulus of the ice and the length of the floating tongue is observed, but also a signature of the friction law parameters on these displacements. The results obtained with the full model open interesting perspectives on the estimation of the parameters of the rheology, geometry and basal friction laws through comparison with field observations. Join the Zoom meeting: https://us02web.zoom.us/j/83303250909?pwd=alE0NVNHQXJrbUhZQ3Vpc05XaDhmQT09 meeting ID : 833 0325 0909 Password : 050263 If you wish to attend the Defence in the Amphitheatre, please inform me by email (), the number of places being limited.