Breaking the Ice: Identifying Hydraulically Forced Crevassing

Hudson, T. S and Brisbourne, A. M. and White, R. S. and Kendall, J. M. and Arthern, R. and Smith, A. M. (2020) Breaking the Ice: Identifying Hydraulically Forced Crevassing. Geophysical Research Letters, 47 (21). ISSN 0094-8276 DOI https://doi.org/10.1029/2020GL090597

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Official URL: https://doi.org/10.1029/2020GL090597

Abstract

Hydraulically forced crevassing is thought to reduce the stability of ice shelves and ice sheets, affecting structural integrity and providing pathways for surface meltwater to the bed. It can cause ice shelves to collapse and ice sheets to accelerate into the ocean. However, direct observations of the hydraulically forced crevassing process remain elusive. Here we report a novel method and observations that use icequakes to directly observe crevassing and determine the role of hydrofracture. Crevasse icequake depths from seismic observations are compared to a theoretically derived maximum dry crevasse depth. We observe icequakes below this depth, suggesting hydrofracture. Furthermore, icequake source mechanisms provide insight into the fracture process, with predominantly opening cracks observed, which have opening volumes of hundredths of a cubic meter. Our method and findings provide a framework for studying a critical process that is key for the stability of ice shelves and ice sheets and, therefore, future sea level rise projections.

Item Type: Article
Uncontrolled Keywords: 2020AREP; IA76
Subjects: 02 - Geodynamics, Geophysics and Tectonics
Divisions: 02 - Geodynamics, Geophysics and Tectonics
07 - Gold Open Access
12 - PhD
Journal or Publication Title: Geophysical Research Letters
Volume: 47
Identification Number: https://doi.org/10.1029/2020GL090597
Depositing User: Sarah Humbert
Date Deposited: 06 Nov 2020 17:57
Last Modified: 06 Nov 2020 17:57
URI: http://eprints.esc.cam.ac.uk/id/eprint/4921

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