AQA GCSE - Coasts Flashcards
(36 cards)
How do waves form?
- By wind blowing over the sea.
- Friction with the surface of the water causes ripples that develop into waves.
- Tsunamis form when earthquakes or volcanic eruptions shake the sea bed.
What is fetch?
The distance that wave-generating winds blow across the water.
REMEMBER!!!
The longer the fetch, the bigger the wave.
What are the two types of waves?
Constructive waves and Destructive waves
Constructive Waves
Formed by storms often hundreds of kilometers away. Common in summer.
Destructive Waves
Formed by local storms close to the coast. Common in winter.
Why do cliffs collapse?
Because of weathering - the weakening or decay of rock due to action of weather, plant and animals.
Types of weathering
- Mechanical (physical)
- Chemical
- Bilogical
Mechanical weathering
the disintergration of rock e.g. freeze-thaw
Chemical weathering
caused by chemical changes. e.g. carbination
Biological weathering
caused by the actions of flora and fauna, e.g. plant roots grow in cracks in rocks, and animals (e.g. bunnies) burrow into weak rocks.
What is mass movement?
the doward movement (sliding) of weathered material and rock under the infulence of gravity.
What are the four types of mass movement?
- Rockfall
- Landslide
- Mudflow
- Rotational slip
Rockfall
rock breaks away often due to freeze-thaw (MECHANICAL)
Landslide
blocks of rock sliding downhill (BIOLOGICAL)
Mudflow
saturated soil and weak rocks flow downhill (BIOLOGICAL)
Rotational slip
slump of saturated soil and weak rock along a curved surface (CHEMICAL)
What is coastal erosion?
transport of material away from the coast line.
What are the five types of coasta erosion?
- Solution
- Corrasion
- Abrasion
- Attrition
- Hydrolic Power
Solution
Dissolving of soluble chemicals in rock, e.g. limestone.
Corrasion
Rock fragments picked up by the sea and thrown at the cliff, scrape and wear away at the cliff.
Abrasion
The ‘sandpapering’ effect of the pebbles griding over a rocky platform.
Attrition
Rock fragments carried by the sea knock against each ther becoming smaller/more rounded.
Hydraulic Power
The power of the waves as they hit a cliff. Trapped air is forced into cracks in the rock eventually causing it to break up.