Coastal Erosion Flashcards
Wave pounding
Steep and powerful waves break at the foot of a cliff and exert high force which pounds away at the cliff.
Hydraulic action
Waves impact cliff faces, forcing air into cracks under high pressure, widening them. Over time, pressure increases and cracks grow causing rock fragments to break off.
Abrasion
Repeated action of waves breaking on a cliff removes material, this acts as sandpaper causing an increase in rate of erosion.
Attrition
Beach material previously eroded are knocked together, reducing their size and increasing their roundness and smoothness.
Corrosion/Solution
Rocks e.g. Limestone, are vulnerable to carbonic acid sea water and therefore dissolve into it. The rate of dissolution is decreased as other carbonates and minerals in the water increases.
How does the ‘strength of waves breaking along the coastline’ affect the rate of erosion?
Longer fetch and stronger winds create bigger, more powerful waves that are more erosive.
How does ‘Bathymetry (underwater elevation)’ affect the rate of erosion?
As waves approach a coastline, they lose energy by friction with the sea bed. This also impacts strength of the waves.
How do ‘Landforms’ affect the rate of erosion?
Landforms reduce waves erosive power.
For example, BEACHES increase the distance waves travel before they reach the cliff, reducing their energy.
For example, HEADLANDS cause wave refraction, reducing erosive power in one area while increasing in another.
How does ‘Weathering’ affect the rate of erosion?
Weathering creates weakness in rocks that exaggerate erosion.
E.g. Freeze-thaw weathering, creates cracks in rock, rock becomes more susceptible to hydraulic action.
How does ‘Human Impacts’ affect the rate of erosion?
Human activities often increase wave strength. For example, dredging reduces energy dissipation due to deeper water of incoming waves, increasing erosion.
