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Strongly Depth‐Dependent Ice Fabric in a Fast‐Flowing Antarctic Ice Stream Revealed With Icequake Observations

Kufner, S.-K. ORCID iD icon 1; Wookey, J.; Brisbourne, A. M.; Martín, C.; Hudson, T. S.; Kendall, J. M.; Smith, A. M.
1 Geophysikalisches Institut (GPI), Karlsruher Institut für Technologie (KIT)

Abstract:

The crystal orientation fabric of glacier ice impacts its strength and flow. Crystal fabric is therefore an important consideration when modeling ice flow. Here, we show that shear-wave splitting (SWS) measured with glacial microseismicity can be used to invert seismic anisotropy and ice fabric, if represented in a statistical sense. Rutford Ice Stream (RIS) is a fast-flowing Antarctic ice stream, a setting crucial for informing large-scale ice sheet models. We present >200,000 SWS measurements from glacial microseismicity, registered at a 38-station seismic network located ∼40 km upstream of the grounding line. A representative subset of these data is inverted for ice fabric. Due to the character of SWS, which accumulates along the raypath, we include information on the depth structure from radar measurements. We find that the following three-layer configuration fits the data best: a broad vertical cone fabric near the base of RIS (500 m thick), a thick vertical girdle fabric, orientated perpendicular to flow, in the middle (1,200 m thick), and a tilted cone fabric in the uppermost 400 m. Such a variation of fabric implies a depth-dependent strength profile of the ice with the middle layer being ∼3.5 times harder to deform along flow than across flow. ... mehr


Verlagsausgabe §
DOI: 10.5445/IR/1000157738
Veröffentlicht am 16.09.2023
Originalveröffentlichung
DOI: 10.1029/2022JF006853
Scopus
Zitationen: 1
Web of Science
Zitationen: 1
Dimensions
Zitationen: 1
Cover der Publikation
Zugehörige Institution(en) am KIT Geophysikalisches Institut (GPI)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 03.2023
Sprache Englisch
Identifikator ISSN: 2169-9003, 2169-9011
KITopen-ID: 1000157738
Erschienen in Journal of Geophysical Research: Earth Surface
Verlag John Wiley and Sons
Band 128
Heft 3
Seiten e2022JF006853
Vorab online veröffentlicht am 15.03.2023
Nachgewiesen in Web of Science
Dimensions
Scopus
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