Abstract
Laterally propagating, through-cutting rifts govern the iceberg calving component of Antarctic ice-shelf mass balance and determine the geometry of the seaward fronts of these floating ice masses. Despite their importance, physical limits on rift propagation are not well understood, there have been few forward-modelling studies of rift behaviour and there are no accessible modelling frameworks with which to meet these challenges. The present work describes and justifies a novel numerical approach that applies lin- ear elastic fracture mechanics (LEFM) to simulate antarctic ice-shelf rifts, addressing this gap. An ice flow model is used to infer a field of realistic source stresses from observed velocities and an elastic domain is subjected to an equivalent stress field, from which the propensity for and orienta- tion of rift propagation can be obtained using LEFM. The extended finite element method is used within the elastic domain for efficient calculation of stress intensity factors that characterise rift behaviour. A case study is done simulating a central Ross Ice Shelf under different rift internal boundary conditions. The model results suggest that a comparison between ice shelf principal stresses and a stress imbalance between ice and ocean water overburden is a great indicator of rift formation and propagation. These simulations also demonstrate that boundary conditions within the rift are key in determining its shape, future and effect on the shelf.