Elmer/Ice News

Backstress induced failure at Thwaites Eastern Ice Shelf

The Thwaites Eastern Ice Shelf (TEIS), the only remaining pinned floating extension of Thwaites Glacier, has Modelled and observed fracture on TEIS (from the article)undergone a phase of significant fragmentation during the last decade.  Observations as well as simulations support the theory that the glacier's acceleration increased the damage in the floating part of the ice by backstress imposed from its pinning points. HiDEM (Helsinki Discrete Element Model) simulations primed with basal friction coefficients obtained by means of Elmer/Ice simulations using data assimilation indicate a significant zone of shear, upstream of the main pinning point, seeding damage on the shelf. Subsequently, basal melting and positive feedback between damage and strain rates weakened TEIS, allowing damage to accumulate. Despite a diminishing backstress caused by a shrinking pinning point, accumulation of damage has ensured that the ice in TEIS in the shear zone remained the weakest link in the system. Besides hydro-fracturing and detachment from pinning points, this study suggest a third mechanism for ice-shelf instability: backstress triggered failure. 

Read more: Benn, D. I., A. Luckman, J.A. Åström, A. Crawford, S.L. Cornford, S.L.. Bevan, T. Zwinger, R. Gladstone, K. Alley, E. Pettit, and J. Bassis, 2022, Rapid fragmentation of Thwaites Eastern Ice Shelf.  The Cryosphere, 16, 2545–2564, doi:10.5194/tc-16-2545-2022 

 

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