Wave pounding is the 'sledge hammer' effect of tonnes of water crashing against cliffs. It shakes and weakens the rocks leaving them open to attack from hydraulic action and abrasion. Eroded material gets carried away by the wave. Wave pounding is particularly fierce in a storm, where the waves are exceptionally large, and have a lot of energy. It is an important engineering consideration in the construcgtions ostructures such as seawalls and dams.
References
Wave pounding Wikipedia(Text) CC BY-SA