Unravelling the importance of iceberg-calving-induced hydrodynamic forces to monitor Greenland ice mass loss with seismic inversion of glacial earthquakes

Marine-terminating glaciers play a significant role he loss of ice mass from Greenland. Iceberg calvings are thought to account for about half of Greenland ice mass loss. These events produce seismic waves (glacial earthquakes) recorded by global seismic networks and contain information such as the iceberg volume and the forces acting during the event. Previous work showed that seismic inversion, coupled to numerical modeling, can be used to decipher the glacial earthquake signal [Sergeant 2019]. However, the lack of consideration for the hydrodynamic forces applied onto the glacier leads to large uncertainties in the iceberg volume estimations. Therefore, based on previous work, a Computational Fluid Dynamics (CFD) model is employed to model the complex fluid/structure interaction between a capsizing iceberg and the ocean. The simulations match results from laboratory experiments with great accuracy (rotation kinematics, effect of calving type, hydrodynamic pressure, etc.) [De Pinho Dias 2025].In this presentation, we will show how the forces applied onto a simple model of Helheim glacier during an iceberg calving depend on geometrical parameters (iceberg height, aspect ratio, water depth, iceberg drop height). The pressure force exerted onto the glacier front has a significant magnitude of more than 50 % of the iceberg/glacier contact force which acts in the opposite direction.The forces are then converted into seismic signals and show a very good match with the signal recorded at 8 stations in Greenland.In addition, we will show the path of particle tracers advected by calving-induced water currents. Sergeant, A. et al. (2019) ‘Monitoring Greenland ice sheet buoyancy-driven calving discharge using glacial earthquakes’, Annals of Glaciology, 60(79), pp. 75–95. doi:10.1017/aog.2019.7. De Pinho Dias, N., Leroyer, A., Mangeney, A. and Castelnau, O., 2025. Fluid-structure modeling of iceberg capsize. Ocean Engineering, 336, p.121765. doi:10.1016/j.oceaneng.2025.121765