Basal icequakes and sticky spots: Rutford Ice Stream, West Antarctica, near the grounding line

Lee I, Anandakrishnan S, Alley RB, Smith AM, Brisbourne AM, Bacon CA, Willet A, Kufner SK (2026)

Publication Type: Journal article

Publication year: 2026

Journal

Annals of Glaciology International Glaciological Society

DOI: 10.1017/aog.2026.10059

Abstract

We located over one million icequakes that occurred during a 23-day period upglacier of the grounding line of Rutford Ice Stream, West Antarctica. To investigate basal conditions and better understand the sliding process, we focused on sticky spots, spatially constrained clusters of regularly repeating basal icequakes. We developed a multi-step workflow combining location and clustering to identify sticky spots with high confidence. The basal icequakes are consistent with low-angle slip in the ice flow direction. Seismicity during our recording period showed weak tidal correlation and a minor sensitivity to atmospheric pressure, suggesting limited external forcing of basal processes. Icequake density was elevated on stoss sides of topographic highs likely characterized by exposed bedrock or compacted tills, and in low-lying moats eroded upglacier of topographic highs, as well as in troughs extending downglacier from the moats, likely reflecting hard beds that promote stick-slip. Local magnitudes followed a Gutenberg-Richter distribution with two distinct high (>2) b-values. Within sticky spots, repeating seismicity featured consistent waveforms and strong positive correlations between local magnitude and inter-event time. During multi-hour active phases, seismic slip in sticky spots can fully accommodate ice flow, highlighting the role of stick-slip motion in basal sliding near the RIS grounding line. These results will help inform sliding relations used in numerical ice flow models.

Authors with CRIS profile

Sofia-Katerina Kufner Professur für Tektonik

Involved external institutions

Pennsylvania State University (Penn State) US United States (USA) (US) Lamont-Doherty Earth Observatory US United States (USA) (US) University of Cambridge GB United Kingdom (GB)

How to cite

APA:

Lee, I., Anandakrishnan, S., Alley, R.B., Smith, A.M., Brisbourne, A.M., Bacon, C.A.,... Kufner, S.-K. (2026). Basal icequakes and sticky spots: Rutford Ice Stream, West Antarctica, near the grounding line. Annals of Glaciology. https://doi.org/10.1017/aog.2026.10059

MLA:

Lee, Ian, et al. "Basal icequakes and sticky spots: Rutford Ice Stream, West Antarctica, near the grounding line." Annals of Glaciology (2026).

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