Basal hydrofractures near sticky patches

TL;DR

This paper models how spatial variations in basal stress, especially sticky patches, influence the initiation and growth of basal crevasses in ice sheets using linear elastic fracture mechanics.

Contribution

It introduces a theoretical model quantifying the impact of shear stress variations and sticky patches on basal crevasse development in ice sheets.

Findings

Sticky patches promote basal crevasse initiation.

Sticky patches increase crevasse length and influence their trajectories.

Conditions for sticky-patch-induced crevassing are identified through parameter analysis.

Abstract

Basal crevasses are macroscopic structural discontinuities at the base of ice sheets and glaciers. Motivated by observations and the mechanics of elastic fracture, we hypothesise that in the presence of basal water pressure, spatial variations in basal stress can promote and localise basal crevassing. We quantify this process in the theoretical context of linear elastic fracture mechanics. We develop a model evaluating the effect of shear stress variation on the growth of basal crevasses. Our results indicate that sticky patches promote the initiation of basal crevasses, increase their length of propagation into the ice and, under some conditions, give them curved trajectories that incline upstream. A detailed exploration of the parameter space is conducted to gain a better understanding of the conditions under which sticky-patch-induced basal crevassing likely occurs beneath ice sheets and glaciers.