Predicting Stability of Ice Shelves with Crevasses: A Numerical Experiment

Abstract:

Crevasses exist throughout many ice shelves as a precursor of large calving events which serve as the main source of mass loss for most ice sheets and glaciers. The stability of an ice shelf depend largely on whether the crevasses can grow and penetrate the entire ice thickness or will be filled with ice and eventually disappear. In light of recent observations of basal crevasses hundreds of meters wide, we use a finite element model to relax this condition and examine the effect that large basal crevasses have on the velocity and stress field within the ice shelf. The relative strength between the tensile stress pulling a crevasse open and the opposing hydrostatic pressure drawing ice in to heal can serve as a valuable proxy for determining the evolution of a crevasse, thus allowing us to infer regions vulnerable to fracture and those that are more stable based on ice shelf velocity and thickness measurements.