Processes of Wave Erosion
Abrasion
Scratching of ocean floor by materials carried by the back wash.
Corrasion
Hurling of pebbles and rock fragments against the rocks causing some particles to break off.
Attrition
Rock fragments dragged up and down by the swash and backwash hitting against each other becoming smaller in size. It provides tools for abrasion and corrosion.
Hydraulic Action
Removal of materials from the coast by action of the force of moving water.
Direct wave force
Large amounts of wave water crush against a rock face weakening and eventually breaking of the rock.
Compressed air action
- Waves crush against a rock.
- The force of water pushes air into cracks compressing it and exerting pressure causing them to widen.
- Wave retreats causing trapped air to expand resulting in sudden pressure release causing cracks to expand further.
- The process is repeated several times causing the rocks to shatter.
Solution
Some soluble minerals in rocks dissolve directly in water and are carried away in solution leaving cavities in rocks.
Corrosion
Some minerals such as limestone reacting with sea water which has dissolved carbonic acid.
Factors influencing wave erosion
- Waves must have strong backwash and a weak swash
- Slope -The coast that slopes steeply into the sea favours erosion.
- The load-large amount provides more abrasive tools. Angular shaped load is more effective in abrasion.
- Amount of water in a wave – the larger the amount the greater the hydraulic force.
