Theoretical Stability of Ice Shelf Basal Crevasses with a Vertical Temperature Profile

Abstract

Basal crevasses threaten the stability of ice shelves through the potential to form rifts and calve icebergs. Different existing fracture theories lead to distinct calving predictions. Furthermore, it is important to determine the dependence of crevasse stability on temperature due to large vertical temperature variations on ice shelves. In this work, we explore the transition from basal crevasses to full thickness fractures considering the vertical temperature structure. Nye’s Zero-Stress approximation violates Newton’s second law. By upholding horizontal force balance, it has been shown analytically that the threshold stress for rift initiation is that of a freely- floating unconfined ice tongue. We generalize the force balance argument to show that while temperature structure influences crack depths, the threshold rifting stress is insensitive to temperature. In the classical Nye’s theory, basal crevasses would develop into rifts at a stress twice of that in our Nye’s theory adhering to horizontal force balance.