Storm overtopping of a marine terrace at the penultimate stage of evolution

The youngest uplifted marine terrace at Kahutara Point on Māhia Peninsula, New Zealand, is undergoing rapid retreat (backwear) despite being fronted by a wide contemporary shore platform that attenuates wave energy. In this paper, wave energy and water level were recorded across the shore platform, and these data were used to model (a) how frequently waves reach the terrace riser and potentially erode it and (b) how frequently waves overtop the terrace. Analyses of wave data across shore normal transects show that under quiescent and storm conditions >90% of the energy delivered to the back beach and terrace riser is at infragravity frequencies (i.e.,