C - Costal processes Flashcards
What shapes our coasts?
The action of waves
How are waves created?
By wind blowing over the surface of the sea
What three things influence the size and energy of a wave?
- How long the wind has been blowing
- The strength of the wind
- How far the wave has travelled (fetch)
What is a fetch?
The distance the wind blows over the surface of the water
What are the two different types of waves?
Constructive and Destructive
What is a swash?
When a wave break, and water is washed up the beach
What is a backwash?
When water runs back down the beach
With a constructive wave…
The swash is stronger than the backwash
With a destructive wave…
The backwash is stronger than the swash
Give a few features about destructive:
- Created in stormy conditions
- Created from big strong waves when the wind is powerful and has been blowing for a long time
- Wave energy is high and wave has traveled over long fetch
- Erode the coast
- Short wave length high and steep
Give a few features about constructive waves:
- Created in calm weather
- Less powerful then destructive waves
- Break on the shore and deposit material forming beaches
- Long wavelength low in height
What shapes are coastline?
The sea
What is costal erosion?
The wearing away and break up of rocks along our coastline
What type of wave causes costal erosion?
Destructive waves
What are the four processes of erosion that wear down the coast?
- Hydraulic power
- Abrasion
- Attrition
- Solution
Describe hydraulic power
Waves crash against the rocks and compress the air in the cracks. This puts pressure on the rock. Repeated compression widens the cracks and makes bits of rocks break off.
Describe Abrasion
Eroded particles in the water scrape and rub against rocks, removing small peices
Describe attrition
Eroded particles on the water smash into each other and break into smaller fragments. Their edges also get rounded off when they rub together
Describe Solution
Weak carbonic acid in seawater dissolves rock like chalk and limestone
What two ways are rocks broken down by?
Mechanical and chemical weathering
What is weathering?
The breakdown of rocks from where they are
What is erosion?
Rocks broken down and carried out by something else eg seawater
