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Highly variable friction and slip observed at Antarctic ice stream bed
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S. K. Kufner ,
A. M. Brisbourne ,
J. M. Kendall ,
A. M. Smith ,
R. B. Alley ,
R. J. Arthern,
Tavi Murray
Nature Geoscience
Swansea University Author:
Tavi Murray
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DOI (Published version): 10.1038/s41561-023-01204-4
Abstract
The slip of glaciers over the underlying bed is the dominant mechanism governing the migration of ice from land into the oceans, with accelerating slip contributing to sea-level rise. Yet glacier slip remains poorly understood, and observational constraints are sparse. Here we use passive seismic ob...
| Published in: | Nature Geoscience |
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| ISSN: | 1752-0894 1752-0908 |
| Published: |
Springer Science and Business Media LLC
2023
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| Online Access: |
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| URI: | https://cronfa.swan.ac.uk/Record/cronfa63652 |
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| Abstract: |
The slip of glaciers over the underlying bed is the dominant mechanism governing the migration of ice from land into the oceans, with accelerating slip contributing to sea-level rise. Yet glacier slip remains poorly understood, and observational constraints are sparse. Here we use passive seismic observations to measure both frictional shear stress and slip at the bed of the Rutford Ice Stream in Antarctica using 100,000 repetitive stick-slip icequakes. We find that basal shear stresses and slip rates vary from 104 to 107 Pa and 0.2 to 1.5 m per day, respectively. Friction and slip vary temporally over the order of hours, and spatially over 10s of metres, due to corresponding variations in effective normal stress and ice–bed interface material. Our findings suggest that the bed is substantially more complex than currently assumed in ice stream models and that basal effective normal stresses may be significantly higher than previously thought. Our observations can provide constraints on the basal boundary conditions for ice-dynamics models. This is critical for constraining the primary contribution of ice mass loss in Antarctica and hence for reducing uncertainty in sea-level rise projections. |
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| Keywords: |
Climate Change, Cryospheric Science, Seismology |
| College: |
Faculty of Science and Engineering |
| Funders: |
T.S.H., A.M.B., A.M.S. and T.M. were funded by Natural Environment Research Council grants NE/G014159/1 and NE/G013187/1.
Seismic instruments were provided by NERC SEIS-UK (loans 1017 and 1111), by BAS and by the Incorporated Research Institutions for Seismology (IRIS) through the Portable Array Seismic Studies of the Continental Lithosphere (PASSCAL) Instrument Center at New Mexico Tech.
The facilities of the IRIS Consortium are supported by the National Science Foundation’s Seismological Facilities for the Advancement of Geoscience (SAGE) award under cooperative support agreement EAR-1851048. |