Types of erosion
Erosion is the wearing away of rock along the coastline. Waves which remove material from the beach. The swash is weaker than the backwash. are responsible for erosion on the coastline. Erosion occurs where waves have direct contact with the rock. There are four types of erosion:
- Hydraulic action - this is the sheer power of the waves as they smash against the cliff. Air becomes trapped and compressed into cracks in the rock with explosive force causing the rock to break apart.
- Abrasion - this is when pebbles grind along a rock platform or cliff base much like sandpaper. Over time the rock becomes smooth.
- Attrition - this is when rocks that the sea is carrying knock against each other. They break apart to become smaller and more rounded.
- Solution - this is when sea water dissolves certain types of rocks. In the UK, chalk and limestone cliffs (soft rock) are prone to this type of erosion.