Granular decoherence precedes ice mélange failure and glacier calving at Jakobshavn Isbræ
Cassotto, R.K.; Burton, J.C.; Amundson, J.M.; Fahnestock, M.A.; Truffer, M. (2021). Granular decoherence precedes ice mélange failure and glacier calving at Jakobshavn Isbræ. Nature Geoscience 14(6): 417-422. https://dx.doi.org/10.1038/s41561-021-00754-9
In: Nature Geoscience. Nature Publishing Group: London. ISSN 1752-0894; e-ISSN 1752-0908, more
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| Authors | | Top |
- Cassotto, R.K.
- Burton, J.C.
- Amundson, J.M.
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- Fahnestock, M.A.
- Truffer, M.
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| Abstract |
The stability of the world’s largest glaciers and ice sheets depends on mechanical and thermodynamic processes occurring at the glacier–ocean boundary. A buoyant agglomeration of icebergs and sea ice, referred to as ice mélange, often forms along this boundary and has been postulated to affect ice-sheet mass losses by inhibiting iceberg calving. Here, we use terrestrial radar data sampled every 3 min to show that calving events at Jakobshavn Isbræ, Greenland, are preceded by a loss of flow coherence in the proglacial ice mélange by up to an hour, wherein individual icebergs flowing in unison undergo random displacements. A particle dynamics model indicates that these fluctuations are likely due to buckling and rearrangements of the quasi-two-dimensional material. Our results directly implicate ice mélange as a mechanical inhibitor of iceberg calving and further demonstrate the potential for real-time detection of failure in other geophysical granular materials. |
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