Physical CAUSES of coastal erosion
- Created by: Jes10
- Created on: 28-10-17 05:00
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- Physical causes of coastal erosion
- Waves
- Destructive or constructive
- Destructive-steeper gradient waves have more energy and cause more erosion
- These high powerful waves breaking at the foot of the cliffs are more damaging due to point at which energy is released
- Constructive-gentle gradient on the waves so more deposition than erosion
- Destructive-steeper gradient waves have more energy and cause more erosion
- Fetch is a factor that affects wave type
- Three factors that affect wave type: Speed, Distance and Time
- Destructive or constructive
- Geology
- Lithology
- Less resistant rock type faster rate of erosion e.g. clay
- More resistant type of rock, slower rate of erosion e.g. granite
- Structure
- Different rock types run parallel to the coastline=CONCORDANT
- The sea will only be able to break through the resistant rock in some places
- Different rock types run perpendicular to the coastline-DISCORDANT
- less resistant rocks are exposed and will erode more quickly but we will get different rates of erosion so HEADLANDS AND BAYS would start to emerge
- Different rock types run parallel to the coastline=CONCORDANT
- Lithology
- Geomorphology
- The shape of the coastline will affect the rate of erosion
- Headlands cause wave refraction, making waves converge and combine their energy
- Wider shallower bays allows waves to diverge losing energy due to friction with the sea bed
- Headlands cause wave refraction, making waves converge and combine their energy
- Beach Presence
- Wider beach more wave energy lost due to friction
- Narrower beach means breaking point will be closer to the coastline and less energy will be lost due to less friction
- Beach material
- Shingle and pebbles will allow more water to infiltrate and casue more wave energy to be lost due to friction
- Because shingle and pebble beaches leave less energy for backwash, material tends to move upwards making the beach steeper and therefore encourages higher rates of erosion
- Sandy beaches allow less infiltration and cause less friction and allow for a higher rate of erosion
- Shingle and pebbles will allow more water to infiltrate and casue more wave energy to be lost due to friction
- The shape of the coastline will affect the rate of erosion
- Waves
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