Preprints
https://doi.org/10.5194/egusphere-2023-1957
https://doi.org/10.5194/egusphere-2023-1957
19 Sep 2023
 | 19 Sep 2023

Failure strength of glacier ice inferred from Greenland crevasses

Aslak Grinsted, Nicholas Mossor Rathmann, Ruth Mottram, Anne Munck Solgaard, Joachim Mathiesen, and Christine Schøtt Hvidberg

Abstract. Ice fractures when subject to stress that exceeds the material failure strength. Previous studies have found that a von Mises failure criterion, which places a bound on the second invariant of the deviatoric stress tensor, is consistent with empirical data. Other studies have suggested that a scaling effect exists, such that larger sample specimens have a substantially lower failure strength, implying that estimating material strength from laboratory-scale experiments may be insufficient for glacier-scale modelling. In this paper, we analyze the stress conditions in crevasse onset regions to better understand the failure criterion and strength relevant for large-scale modelling. The local deviatoric stress is inferred using surface velocities and reanalysis temperatures, and crevasse onset regions are extracted from a remotely sensed crevasse density map. We project the stress state onto the failure plane spanned by Haigh–Westergaard coordinates, showing how failure depends on mode of stress. We find that existing crevasse data is consistent with a Schmidt–Ishlinsky failure criterion that places a bound on the absolute value of the maximal principal deviatoric stress, estimated to be (158 ± 44) kPa. Although the traditional von Mises failure criterion also provides an adequate fit to the data with a von Mises strength of (265 ± 73) kPa, it depends only on stress magnitude and is indifferent to the specific stress state, unlike Schmidt–Ishlinsky failure which has a larger shear failure strength compared to tensile strength. Implications for large-scale ice-flow and fracture modelling are discussed.

Aslak Grinsted, Nicholas Mossor Rathmann, Ruth Mottram, Anne Munck Solgaard, Joachim Mathiesen, and Christine Schøtt Hvidberg

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-1957', Anonymous Referee #1, 17 Oct 2023
    • AC1: 'Reply on RC1', Aslak Grinsted, 22 Dec 2023
  • RC2: 'Comment on egusphere-2023-1957', Douglas Benn, 04 Dec 2023
    • AC2: 'Reply on RC2', Aslak Grinsted, 22 Dec 2023
    • AC3: 'Reply on RC2', Aslak Grinsted, 22 Dec 2023

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-1957', Anonymous Referee #1, 17 Oct 2023
    • AC1: 'Reply on RC1', Aslak Grinsted, 22 Dec 2023
  • RC2: 'Comment on egusphere-2023-1957', Douglas Benn, 04 Dec 2023
    • AC2: 'Reply on RC2', Aslak Grinsted, 22 Dec 2023
    • AC3: 'Reply on RC2', Aslak Grinsted, 22 Dec 2023
Aslak Grinsted, Nicholas Mossor Rathmann, Ruth Mottram, Anne Munck Solgaard, Joachim Mathiesen, and Christine Schøtt Hvidberg
Aslak Grinsted, Nicholas Mossor Rathmann, Ruth Mottram, Anne Munck Solgaard, Joachim Mathiesen, and Christine Schøtt Hvidberg

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Latest update: 19 Apr 2024
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Short summary
Ice fracture can cause glacier crevassing and calving. These natural hazards can also modulate the flow and evolution of ice sheets. In a new study, Grinsted and coauthors use a new high-resolution dataset to determine a new failure criterion for glacier ice. Surprisingly, the strength of ice depends on the mode of deformation, and this has potential implications for the currently-used flow law of ice.