Ice fabric in an Antarctic ice stream interpreted from seismic anisotropy

Smith, Emma C.; Baird, Alan F.; Kendall, Michael; Martín, Carlos ORCID: https://orcid.org/0000-0002-2661-169X; White, Robert S.; Brisbourne, Alex M. ORCID: https://orcid.org/0000-0002-9887-7120; Smith, Andrew M. ORCID: https://orcid.org/0000-0001-8577-482X. 2017 Ice fabric in an Antarctic ice stream interpreted from seismic anisotropy. Geophysical Research Letters, 44 (8). 3710-3718. https://doi.org/10.1002/2016GL072093

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Abstract/Summary

Here we present new measurements of an anisotropic ice fabric in a fast moving (377 ma−1) ice stream in West Antarctica. We use ∼6000 measurements of shear wave splitting observed in microseismic signals from the bed of Rutford Ice Stream, to show that in contrast to large-scale ice flow models, which assume that ice is isotropic, the ice in Rutford Ice Stream is dominated by a previously unobserved type of partial girdle fabric. This fabric has a strong directional contrast in mechanical properties, shearing 9.1 times more easily along the ice flow direction than across flow. This observed fabric is likely to be widespread and representative of fabrics in other ice streams and large glaciers, suggesting it is essential to consider anisotropy in data-driven models to correctly predict ice loss and future flow in these regions. We show how passive microseismic monitoring can be effectively used to provide these data.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1002/2016GL072093
Programmes:	BAS Programmes > BAS Programmes 2015 > Ice Dynamics and Palaeoclimate
ISSN:	0094-8276
Additional Keywords:	ice stream, ice fabric, anisotropy, microseismics, icequakes, Antarctica
Date made live:	20 Jun 2017 14:11 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/514001

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