Coastal erosion

Coastal landscapes are formed by a combination of erosion, transportation and deposition processes.

Dorset coastline
Dorset coastline

The force of the sea changes the coastal landscape. Waves get their energy from the wind.

The size of the wave is determined by:

  • the speed of the wind
  • the length of time the wind has been blowing
  • the distance of sea it has travelled over (the fetch)

The stronger the wave, the more erosion it will cause.

The four processes involved in erosion are:

Hydraulic action

Hydraulic action is the sheer force of waves crashing against the shore and cliffs. The power of the waves forces air into cracks, compresses it and blows the rock apart as the pressure is released.


Attrition happens when rocks and pebbles carried by the waves smash into each other, wearing each other away and gradually becoming smaller, rounder and smoother.


Abrasion, also called corrasion, is the process of rocks and pebbles carried by the waves wearing away rocks as they are thrown against cliffs.


Solution (also called corrosion) is when chemicals in the seawater dissolve minerals in the rocks, causing them to break up.