EGU2020-7033, updated on 07 Aug 2020
https://doi.org/10.5194/egusphere-egu2020-7033
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Modelling the source of glacial earthquakes for a better understanding of the impact of iceberg capsize on glacier stability

Pauline Bonnet1,2,3, Vladislav Yastrebov3, Alban Leroyer4, Patrick Queutey4, Anne Mangeney1,5,6, Olivier Castelneau2, Eleonore Stutzmann1, Jean-Paul Montagner1, and Amandine Sergeant7
Pauline Bonnet et al.
  • 1Institut de Physique du Globe de Paris, Seismology, Paris, France (pbonnet@ipgp.fr)
  • 2Laboratoire Procédés et Ingénierie en Mécanique et Matériaux, CNRS, ENSAM, CNAM, Paris, France
  • 3MINES ParisTech, PSL University, Centre des Matériaux, CNRS UMR 7633, Evry, France
  • 4Laboratoire LHEEA, METHRIC Team, UMR CNRS n°6598, Centrale Nantes, France
  • 5Université Paris-Diderot 7, Sorbonne Paris Cité, UFR STEP, Paris, France
  • 6Inria, Laboratoire J.-L. Lions, ANGE team, CEREMA, CNRS, Paris, France
  • 7ETH Zurich, Laboratory of Hydraulics, Hydrology and Glaciology (VAW), Zurich, Switzerland

One current concern in climate science is the estimations of the amount of ice loss by glaciers each year and the corresponding rate of sea level rise. Greenland ice sheet contribution is significant with about 30% to the global ice mass losses. Ice loss in Greenland is distributed approximately equally between loss in land by surface melting and loss at the front of marine-terminating glaciers that is modulated by dynamic processes. Dynamic mass loss includes both submarine melting and iceberg calving. The processes that control ablation at tidewater glacier termini, glacier retreat and calving are complex, setting the limits to the estimation of dynamic mass loss and the relation to glacier dynamics. It involves interactions between bedrock – glaciers – icebergs – ice-mélange – water – atmosphere. Moreover, the capsize of cubic kilometer scale icebergs close to a glacier front can destabilize the glacier, generate tsunami waves, and induce mixing of the water column which can impact both the local fauna and flora.

We aim to improve the understanding of iceberg capsize using a mechanical modeling of iceberg rotation against the glacier terminus, constrained by the generated seismic waves that are recorded at teleseismic distances. To achieve this objective, we develop a fluid-structure interaction model for the capsizing iceberg. Full scale fluid-structure interaction models enable accurate simulation of complex fluid flows in presence of rigid or deformable solids and in presence of free surfaces. However, such models are computationally very expensive. Therefore, our strategy is to construct a simple solid dynamics model involving contact and friction, whose simplified interaction with water is governed by parametrized forces and moments. We fine tune these parametrized effects on an iceberg capsizing in contact with a glacier with the help of reference direct numerical simulations of fluid-structure interactions involving full resolution of Navier-Stokes equations. We assess the sensitivity of the glacier dynamics to the glacier-bedrock friction law and the conditions for triggering a stick-slip motion of the glacier due to iceberg capsize. The seismogenic sources of the capsizing iceberg in contact with a glacier simulated with our model are then compared to the recorded seismic signals for well documented events.

How to cite: Bonnet, P., Yastrebov, V., Leroyer, A., Queutey, P., Mangeney, A., Castelneau, O., Stutzmann, E., Montagner, J.-P., and Sergeant, A.: Modelling the source of glacial earthquakes for a better understanding of the impact of iceberg capsize on glacier stability, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-7033, https://doi.org/10.5194/egusphere-egu2020-7033, 2020

How to cite: Bonnet, P., Yastrebov, V., Leroyer, A., Queutey, P., Mangeney, A., Castelneau, O., Stutzmann, E., Montagner, J.-P., and Sergeant, A.: Modelling the source of glacial earthquakes for a better understanding of the impact of iceberg capsize on glacier stability, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-7033, https://doi.org/10.5194/egusphere-egu2020-7033, 2020

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