Bays and Headlands occurs at areas with alternating hard (more resistant) and soft (less resistant) rocks beginning: Softer rocks eroded and forms bays Harder rocks outcrop to form headlands later (Bay Beach Model): Bays receive low energy waves that deposit sand Headlands receive the highest-energy waves that erode
Arches Formed when a cave is widened and deepened by erosion which eventually breaks through the headland End: roof collapses and forms a stack
Stacks An isolated portion of the cliff Formed when arches widen and roof collapses which results in an isolated portion End: stack is worn away creating a stump Video: http://blip.tv/file/1324806/
Stump Erosion Occurring
Process: Subaerial Cliffs can be eroded by rain fall throughflow extreme conditions of surface runoff weathering with wind and frost which can cause slumping or landslides
Process: Wave Pounding High energy waves = erosion present Break when they hit sea walls of the foot of a cliff and energy is released upon impact May generate shock-waves of up to 30 tonnes per m²
Process: Hydraulic Pressure As a wave approaches the cliff, air is trapped between the rocks. This forms cracks, as more waves come in, more air is trapped. This damages or corrodes the cliff over time. The force of the water as the turbulent current hits river banks pushes water into cracks is increased. Cavitation The resultant shock waves hit and slowly weaken the banks.
Process: Abrasional/Corrasion The most effective method of erosion. Load is carried as waves are hurled at the cliff face.
Process: Human Influences The removal of beach material on the cliffs. The persistent development on the tops of cliffs contributes to rapid soil erosion. Effects of erosion can be reduced by the construction of sea defenses. Without human influences and interference many of these defenses is unnecessary.
Factors affecting the rate of Erosion Breaking point of wave Wave steepness Depth of sea, lengthand direction of fetch, configuration of coastline Supply of beach material Beach Width Rock resistance, structure and dip