The effect of hydrology and crevasse wall contact on calving

Abstract. Calving is one of the main controls on dynamics marine ice sheets. We solve a quasi-static linear elastic fracture problem, forced by viscous pre-stress describing stress state in prior to introduction crack, determine conditions under which an shelf can calve for variety different surface hydrologies. Extending previous work, we develop boundary-element-based method solving enables us ensure that faces crevasses are not spuriously allowed penetrate into each other model. find fixed water table below lead two distinct styles calving, involves abrupt unstable growth crack across finite thickness unbroken potentially history-dependent, while continuous until full has been penetrated, occurs at critical combination extensional stress, level and thickness. give relatively simple analytical calving law latter case. For volume injected complete propagation almost invariably happens realistic stresses if initial length exceeds shallow threshold, but also argue this process more likely correspond formation localized, moulin-like slot permits drainage, rather than event. revisit basal cracks that, model, they propagate readily generated near front. This indicates sophisticated coupling present model (which used very similar form several authors) needs modification incorporate effect torques buoyantly modulated flexure far field.