How do pebbles and rock fragments in waves cause coastal abrasion?

Coastal abrasion occurs when waves act as a transport mechanism for sediment, using pebbles and rock fragments as tools to wear down the shoreline. This process functions similarly to sandpaper, where suspended particles are dragged back and forth against the bedrock by the constant motion of the water.123

As these fragments are agitated by wave energy, they collide with the coast and with each other, gradually grinding down the rock surface and breaking the pebbles themselves into smaller particles like sand. This abrasive action is a primary force in shaping coastal landforms, such as the notches cut into the base of sea cliffs and the development of wave-cut platforms. While waves also exert force through hydraulic pressure and direct impact, the continuous friction caused by these entrained rock fragments is considered one of the most significant contributors to the retreat of shorelines.13