Coastal erosion

The sea changes and shapes the coastal landscape. Coastal erosion is the wearing away and breaking up of rock and beach material found along the coast. Destructive waves will erode the coastline in the following ways.

• The constant force of waves crashing on the shore damages it. In addition air may become trapped in joints and cracks on a cliff face. When the wave breaks the air becomes compressed, weakening the cliff and causing erosion. This is called hydraulic action.
• Waves bring with them bits of rock and sand. These grind down cliffs like the action of sandpaper. This is called abrasion.
• Waves cause rocks and pebbles on the shore to smash into each other and break down and become smaller and smoother. This is called attrition.
• Acids contained in sea water will slowly dissolve certain types of rock such as chalk or limestone. This is called corrosion or solution.

Hydraulic action, abrasion, attrition and solution are demonstrated in the diagram below: