Print Email Facebook Twitter Physical processes controlling the rifting of Larsen C Ice Shelf, Antarctica, prior to the calving of iceberg A68 Title Physical processes controlling the rifting of Larsen C Ice Shelf, Antarctica, prior to the calving of iceberg A68 Author Larour, E. (California Institute of Technology) Rignot, E. (California Institute of Technology; University of California) Poinelli, M. (TU Delft Physical and Space Geodesy; California Institute of Technology; University of California) Scheuchl, B. (University of California) Date 2021 Abstract The sudden propagation of a major preexisting rift (full-thickness crack) in late 2016 on the Larsen C Ice Shelf, Antarctica led to the calving of tabular iceberg A68 in July 2017, one of the largest icebergs on record, posing a threat for the stability of the remaining ice shelf. As with other ice shelves, the physical processes that led to the activation of the A68 rift and controlled its propagation have not been elucidated. Here, we model the response of the ice shelf stress balance to ice shelf thinning and thinning of the ice mélange encased in and around preexisting rifts. We find that ice shelf thinning does not reactivate the rifts, but heals them. In contrast, thinning of the mélange controls the opening rate of the rift, with an above-linear dependence on thinning. The simulations indicate that thinning of the ice mélange by 10 to 20 m is sufficient to reactivate the rifts and trigger a major calving event, thereby establishing a link between climate forcing and ice shelf retreat that has not been included in ice sheet models. Rift activation could initiate ice shelf retreat decades prior to hydrofracture caused by water ponding at the ice shelf surface. Subject AntarcticaFractureIce shelfLarsen CSea level To reference this document use: http://resolver.tudelft.nl/uuid:cca6d59a-0082-473e-a810-99f81ac23e44 DOI https://doi.org/10.1073/pnas.2105080118 ISSN 0027-8424 Source Proceedings of the National Academy of Sciences of the United States of America, 118 (40) Part of collection Institutional Repository Document type journal article Rights © 2021 E. Larour, E. Rignot, M. Poinelli, B. Scheuchl Files PDF e2105080118.full.pdf 3.33 MB Close viewer /islandora/object/uuid:cca6d59a-0082-473e-a810-99f81ac23e44/datastream/OBJ/view