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

• Main Authors: Kufner, S.-K., Wookey, J., Brisbourne, A. M., Martín, C., Hudson, T. S., Kendall, J. M., Smith, A. M.
• Format: Text
• Language: English
• Published: John Wiley and Sons 2023
• Subjects: Antarctic; Rutford; Rutford Ice Stream; Antarc*; Ice Sheet; Ice Stream A
• Online Access: https://dx.doi.org/10.5445/ir/1000157738; https://publikationen.bibliothek.kit.edu/1000157738

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 ...