Abstract

We modelled the flow of the Larsen C ice shelf using an adapted continuum-mechanical model, and applied a fracture criterion to the simulated velocities to investigate its present-day stability. Constraints come from satellite data and geophysical measurements in the 2008-09 austral summer. We obtained excellent agreements between modelled and measured ice-flow velocities, and inferred and observed distributions of rifts and crevasses. Ice-shelf thickness was derived from BEDMAP and ICE Sat data and depth-density profiles inferred from our seismic data. Notable exceptions occur in regions of modelled basal accretion down flow of promontories, thus placing the first quantitative constraints on their mechanical effects. Anomalously soft marine ice, advected into the ice shelf in flow-parallel bands, controls rates of rift propagation downstream. In this presentation I will assess the implications of these findings for the current stability of the Larsen C ice shelf, as compared with the pre-collapse dynamic evolution of the Larsen B ice shelf. I will also present initial analyses and findings from extensive ground-penetrating radar surveys in the 2009-10 austral summer in a prominent zone of basal accretion down-flow of the Joerg Peninsula.