Geography Key Themes

Abraison:  Bits of rock and sand in waves grind down cliff surfaces like sandpaper.

Attrition:  Waves smash rocks and pebbles on the shore into each other, and they break and become smoother.

Hydraulic Action: Air may become trapped in joints and cracks on a cliff face. When a wave breaks, the trapped air is compressed which weakens the cliff and causes erosion.

Solution: Acids contained in sea water will dissolve some types of rock such as chalk or limestone.

Constructive Waves: If the swash is stronger than the backwash - Material is carried on to land and deposited. = Low waves, run Gently up the beach.

Destructive Waves: If the backwash is stronger than the swash - the waves erode the coastline. = High/Steep wave, crashes down on beach.

Definition:

- Is the movement of Material along a coastline by the action of the waves.

- Most frequent wind dirrection.

Preventative Methods:

-Groynes - trap sediment on the beach.

- Cliffs are shaped by Eroision and Weathering.

The Process of a Wave Cut Platform - Seven Siter Cliffs in Sussex:

1. Weather weakens the top of the cliff.
2. The sea attacks the base of the cliff forming a wave-cut notch - Hydraulic Action and Abraison.
3. The notch increases in size causing the cliff to collapse.
4. The backwash carries the rubble towards the sea forming a wave-cut platform.
5. The process repeats and the cliff continues to retreat.