Elastic response of floating glacier ice to impact of long-period ocean waves

[1] Disintegration of ice shelves along the Antarctic Peninsula over the past two decades has clearly demonstrated their high sensitivity to recent changes in the local thermal regime of the atmosphere and ocean and has given rise to the question of whether mechanical coupling with waves in the ocean may provide the triggering mechanism that starts collapse events. Motivated by these events, this study considers a more general question: how ocean waves affect the stress regime of floating ice, and in particular, how ocean waves can influence the creation of fractures and its fatiguing that may lead to breakup and collapse. A new treatment of ice shelf/ocean wave interaction in which the typical “thin plate” approximation is relaxed is presented here, and exact, analytic solutions describing ice shelf stresses induced by long (>60 s period) ocean waves in various idealized ice/ocean geometries are derived. The numerical calculations demonstrate that the amplitudes of the wave-induced stresses are sufficiently large to initiate top to bottom crevasse penetration through the depth of the ice shelf. The cyclic nature of the wave-induced stresses contributes to ice fatigue and damage that is also a precursor to ice shelf disintegration. Although primarily theoretical, the results of the present analysis suggest that ocean waves could be a potential trigger of ice shelf collapse as well as less dramatic, but equally important, episodic calving.