Thèse de Amandine Sergeant | INSTITUT DE PHYSIQUE DU GLOBE DE PARIS

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  Thèse de Amandine Sergeant

Glacial earthquakes seismic wave analysis and modeling
Encadrant (et co-encadrant) : 
Olivier Castelnau (CNRS, PIMM-ENSAM)
Vladislav Yastrebov (CNRS, Mines ParisTech)
Résumé: 

The glacier retreat and thinning acceleration has been observed for 10 years, especially at fast-moving terminating glaciers of the Greenland ice sheet. Those outlet glaciers have a marine-terminating terminus and their dynamic is greatly affected by changes in the ocean temperature and the retreat of sea-ice. Those effects understanding is crucial for a better assessment of the polar ice-sheet mass loss and their contribution to future sea rise level. Glacial earthquakes have been observed during the calving of cubic-km scale unstable icebergs at the margin of Greenland large outlet glaciers.  While capsizing in the water, the iceberg elastically pushes back the glacier terminus that generates long-period seismic waves (10-150 sec) which can be recorded at teleseismic distances. This thesis is about analysing and modeling the seismic source of those glacial earthquake with a mechanical model for calving. This allows to quantify the physical processes at work from seismic records only and will provide new tools for the estimation of the ice mass loss and its impact on the ice-sheet dynamic.

Date de soutenance: 
Wednesday 16 November 2016 - 10:00