Coastal Erosion Flashcards
Hydraulic action
Coastal erosion through hydraulic action happens through the forces of the waves hitting a coastline and trapping air into cracks and joints on the face of a cliff. Over time, the cracks in the cliff face will get larger due to this process and cause the cliff to start splintering away. The changes in air pressure when the wave retreats also causes chunks of the cliff face to loosen and fall off.
Hydraulic action can also cause large pieces of the cliff face to break away just through the power and force of the waves crashing against it.
Just recognise it as the one with the cracks filling with water
Abrasion
The process of abrasion uses sand and small pebbles to wear away and smooth out shorelines and headlands. It’s often known as the sandpaper effect. Abrasion happens most often during stormy conditions, where the waves are picking up lots of material and then breaking against the cliff face with enough force to wear it down.
This type of coastal erosion, especially if the focus of the damage is at the base of the cliff, can cause the cliff face to weaken and potentially collapse.
Just recognise it as the one with the water throwing little rocks
Corrasion
When waves drag sediment, rocks, or any material over the bottom of the sea and wear away at the surface, you get the process of corrasion. These loosened materials are then picked up by the waves and used against the cliff face in the process of abrasion.
Corrasion can also cut away at the base of the cliff face, causing a wave cut notch.
This needs to happen before abrasion
Atrition
Attrition is the process of waves causing rocks that have already been loosened away from the coastline to knock into each other and break apart. This process will cause the rocks to become smaller pebbles, then shingle, and then eventually sand. The rocks being dragged over each other will also smoothen off any jagged edges too.
The process of attrition can cause shorelines to retreat as the material that makes the shoreline gets broken down more and more.
Solution
Certain cliffs in the UK are made out of rocks that can be dissolved by sea water. Chalk and limestone cliffs are particularly vulnerable to this type of erosion, as they contain calcium carbonate. There are weak acidic chemicals in the sea water that react with chemicals in the rock, causing the rock to erode away.
