Monitoring Greenland ice sheet buoyancy-driven calving discharge using glacial earthquakes

• Published in: Annals of Glaciology
• Main Authors: Sergeant, Amandine, Mangeney, Anne, YASTREBOV, Vladislav A., WALTER, Fabian S.A., MONTAGNER, Jean Paul, Castelnau, Olivier, Stutzmann, Eléonore, Bonnet, Pauline, RALAIARISOA, Velotioana Jean-Luc, Bevan, Suzanne, LUCKMAN, Adrian J.
• Other Authors: Institut de Physique du Globe de Paris (IPGP), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire Jacques-Louis Lions (LJLL (UMR_7598)), Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre des Matériaux (MAT), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology Zürich (ETH Zürich), Laboratoire Procédés et Ingénierie en Mécanique et Matériaux (PIMM), Conservatoire National des Arts et Métiers CNAM (CNAM)-Arts et Métiers Sciences et Technologies, HESAM Université (HESAM)-HESAM Université (HESAM), Department of Geography Swansea, Swansea University
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: Seismology; Iceberg calving; Climate change; Glacier calving; Glacier discharge; [SPI]Engineering Sciences [physics]; Greenland; Annals of Glaciology; East Greenland; glacier; Ice Sheet
• Online Access: https://hal.archives-ouvertes.fr/hal-02139311; https://hal.archives-ouvertes.fr/hal-02139311v2/document; https://hal.archives-ouvertes.fr/hal-02139311v2/file/PIMM_AG_2019_SERGEANT.pdf; https://doi.org/10.1017/aog.2019.7

International audience Since the 2000s, Greenland ice sheet mass loss has been accelerating, followed by increasing numbers of glacial earthquakes (GEs) at near-grounded glaciers. GEs are caused by calving of km-scale icebergs which capsize against the terminus. Seismic record inversion allows a reconstruction of the history of GE sources which captures capsize dynamics through iceberg-to-terminus contact. When compared with a catalog of contact forces from an iceberg capsize model, seismic force history accurately computes calving volumes while the earthquake magnitude fails to uniquely characterize iceberg size, giving errors up to 1 km 3 . Calving determined from GEs recorded ateight glaciers in 1993-2013 accounts for up to 21% of the associated discharge and 6% of the Greenland mass loss. The proportion of discharge attributed to capsizing calving may be underestimated by at least 10% as numerous events could not be identified by standard seismic detections (Olsen and Nettles, 2018). While calving production tends to stabilize in East Greenland, Western glaciers have released more and larger icebergs since 2010 and have become major contributors to Greenland dynamic discharge. Production of GEs and calving behavior are controlled by glacier geometry with bigger icebergs being produced when the terminus advances in deepening water. We illustrate how GEs can help in partitioning and monitoring Greenland mass loss and characterizing capsize dynamics.