How does wave erosion create a notch at the base of a sea cliff?

Wave erosion creates a notch at the base of a sea cliff primarily through the mechanical action of waves striking the shoreline. This process involves several key mechanisms:12

• Hydraulic Action: The force of waves hitting the cliff face, particularly during storms, exerts intense pressure that can quarry or pluck blocks of rock from the cliff, especially where the bedrock is jointed or bedded.2
• Abrasion: This is often the most significant factor. Waves carry sand and pebbles, which act as tools that grind, rub, and wear away the bedrock through constant friction as they are dragged back and forth by wave action.2

As waves continuously batter the bedrock at the base, they carve out a recessed notch. Over time, the deepening of this notch undermines the stability of the cliff, eventually causing the overhanging rock to collapse. This cycle of erosion and collapse contributes to the retreat of the coastline and the formation of a wave-cut platform at the cliff's base.312