Vulnerability of firn to hydrofracture: poromechanics modeling
Abstract On the Greenland Ice Sheet, hydrofracture connects the supraglacial and subglacial hydrologic systems, coupling surface runoff dynamics and ice velocity. In recent decades, the growth of low-permeability ice slabs in the wet snow zone has expanded Greenland's runoff zone, but observati...
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Online Access: | http://dx.doi.org/10.1017/jog.2024.47 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143024000479 |
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crcambridgeupr:10.1017/jog.2024.47 2024-09-30T14:35:56+00:00 Vulnerability of firn to hydrofracture: poromechanics modeling Meng, Yue Culberg, Riley Lai, Ching-Yao Princeton University Office of Polar Programs 2024 http://dx.doi.org/10.1017/jog.2024.47 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143024000479 en eng Cambridge University Press (CUP) http://creativecommons.org/licenses/by/4.0/ Journal of Glaciology page 1-14 ISSN 0022-1430 1727-5652 journal-article 2024 crcambridgeupr https://doi.org/10.1017/jog.2024.47 2024-09-04T04:04:50Z Abstract On the Greenland Ice Sheet, hydrofracture connects the supraglacial and subglacial hydrologic systems, coupling surface runoff dynamics and ice velocity. In recent decades, the growth of low-permeability ice slabs in the wet snow zone has expanded Greenland's runoff zone, but observations suggest that surface-to-bed connections are rare, because meltwater drains through crevasses into the porous firn beneath ice slabs. However, there is little quantitative evidence confirming the absence of surface-to-bed fracture propagation. Here, we use poromechanics to investigate whether water-filled crevasses in ice slabs can propagate vertically through an underlying porous firn layer. Based on numerical simulations, we develop an analytical estimate of the water injection-induced effective stress in the firn given the water level in the crevasse, ice slab thickness, and firn properties. We find that the firn layer substantially reduces the system's vulnerability to hydrofracture because much of the hydrostatic stress is accommodated by a change in pore pressure, rather than being transmitted to the solid skeleton. This result suggests that surface-to-bed hydrofracture will not occur in ice slab regions until all pore space proximal to the initial flaw has been filled with solid ice. Article in Journal/Newspaper Greenland Ice Sheet Journal of Glaciology Cambridge University Press Greenland Journal of Glaciology 1 40 |
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Open Polar |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
description |
Abstract On the Greenland Ice Sheet, hydrofracture connects the supraglacial and subglacial hydrologic systems, coupling surface runoff dynamics and ice velocity. In recent decades, the growth of low-permeability ice slabs in the wet snow zone has expanded Greenland's runoff zone, but observations suggest that surface-to-bed connections are rare, because meltwater drains through crevasses into the porous firn beneath ice slabs. However, there is little quantitative evidence confirming the absence of surface-to-bed fracture propagation. Here, we use poromechanics to investigate whether water-filled crevasses in ice slabs can propagate vertically through an underlying porous firn layer. Based on numerical simulations, we develop an analytical estimate of the water injection-induced effective stress in the firn given the water level in the crevasse, ice slab thickness, and firn properties. We find that the firn layer substantially reduces the system's vulnerability to hydrofracture because much of the hydrostatic stress is accommodated by a change in pore pressure, rather than being transmitted to the solid skeleton. This result suggests that surface-to-bed hydrofracture will not occur in ice slab regions until all pore space proximal to the initial flaw has been filled with solid ice. |
author2 |
Princeton University Office of Polar Programs |
format |
Article in Journal/Newspaper |
author |
Meng, Yue Culberg, Riley Lai, Ching-Yao |
spellingShingle |
Meng, Yue Culberg, Riley Lai, Ching-Yao Vulnerability of firn to hydrofracture: poromechanics modeling |
author_facet |
Meng, Yue Culberg, Riley Lai, Ching-Yao |
author_sort |
Meng, Yue |
title |
Vulnerability of firn to hydrofracture: poromechanics modeling |
title_short |
Vulnerability of firn to hydrofracture: poromechanics modeling |
title_full |
Vulnerability of firn to hydrofracture: poromechanics modeling |
title_fullStr |
Vulnerability of firn to hydrofracture: poromechanics modeling |
title_full_unstemmed |
Vulnerability of firn to hydrofracture: poromechanics modeling |
title_sort |
vulnerability of firn to hydrofracture: poromechanics modeling |
publisher |
Cambridge University Press (CUP) |
publishDate |
2024 |
url |
http://dx.doi.org/10.1017/jog.2024.47 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143024000479 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Ice Sheet Journal of Glaciology |
genre_facet |
Greenland Ice Sheet Journal of Glaciology |
op_source |
Journal of Glaciology page 1-14 ISSN 0022-1430 1727-5652 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1017/jog.2024.47 |
container_title |
Journal of Glaciology |
container_start_page |
1 |
op_container_end_page |
40 |
_version_ |
1811639146595221504 |