COMPLEX RESONANT ICE SHELF VIBRATIONS

The problem of ice shelf vibrations forced by incident waves from the open ocean is considered, using a linear hydroelastic model involving combined thin-plate and potential-flow theories. Complex resonances are shown to generate near-resonant ice shelf responses. An efficient algorithm is developed to capture the complex resonances, based on a homotopy, and initialized with the real-valued eigenfrequencies of a problem in which the ice shelf and subshelf water cavity are uncoupled from the open ocean. It is shown the complex resonances may be used to approximate the reflection coefficient in the frequency domain and the large-time ice shelf response to an incident wave packet. Shelf thickening is shown to have a major effect on complex resonances at midrange frequencies, resulting in difficulty exciting certain near resonances in transient problems.