Coastal Erosion, depositional landforms and storm surges Flashcards
What are the four types of coastal erosion?
Corrasion, attrition, solution and hydraulic action
What is corrasion?
Where sediment moved by waves grinds down the side of the cliff
What is attrition?
Where waves move the rocks and pebbles causing them to hit each other and smoothening their surfaces when they break.
What is solution?
When acids in sea water dissolve rocks
What is hydraulic action?
Where air gets trapped in the side of a cliff face and gets compressed by waves breaking forcing the rock apart.
What does concordent mean?
When layers of rock are parallel to the sea
What does discordant mean?
When alternating bands of rock are at right angles to the coast
What is a headland?
A piece of land jutting out to sea
What is a bay?
A broad coastline often with a beach
Where do headland and bays happen?
At discordant a coastline
Why is water in bays shallow?
As the eroded rock is deposited in the bay
What type of erosion takes place at the soft rock in a bay?
Hydraulic action
What’s unique about the geology of Lulworth cove?
It is a concordent coastline and there are alternating bands of hard and soft rock
What is Old Harry?
A stack formed by the erosion of a cliff
Where is Old Harry
South of England along the Dorset coastal town of Swanage.
What kind of erosion was the main reason the formation of Old Harry?
Hydraulic action
What are the steps that lead up to the formation of Old Harry in order?
Headland, crack, cave, arch, stack (Old Harry) and stump (his wife).
What is wave pounding?
The force of waves crashing against cliffs
What is a wave cut platform?
A wide, gentle sloping rocky surface at the foot of a cliff
What is a wave cut notch?
A small indentation (notch) cut into a cliff roughly at the level of high tide caused by erosion
What is fetch?
The distance the wind has blown
What causes waves?
Wind blowing over the sea.
Give features of a constructive wave
Created in calm conditions (summer), builds up beach material, low frequency of 6-8 waves per minute and has a strong swash but weak backwash
Give some features of a destructive wave
Created in stormy conditions (winter), removes material from coast, has a high frequency of 10-15 waves per minute and has a weak swash and strong backwash
What is a spit?
A finger of new land made of sand and shingle jutting out to sea from the coast
What builds behind a spit if at a river estuary?
A salt marsh
What is a salt marsh?
Low lying coastal wetland extending between high and low tide
What is a bar?
A spit that has grown across a bay
What are coastal spits formed through?
Longshore drift
When does a hook form at the end of a spit?
If the wind changes
How long is Hurst Castle spit?
One mile long
What village is Hurst Castle spit near?
Keyhaven, South coast of England
How far from the Isle of Wight is the Hurst Castle spit?
3/4s of a mile away
What is a tombolo?
Similar to a spit but connects to an island
What do you get behind a bar?
A lagoon
What landforms does deposition form?
Spits, bars, beaches, tombolos and sand dunes
Name a tombolo in the UK
St Michael’s Mount in Cornwall
Why is a sand dune formed?
From onshore winds blowing inland
What does a tombolo connect to?
An island
What does longshore drift form?
Tombolos, spits and bars
What is thermal expansion?
Where oceans get warmer and expand
What is a storm surge?
A rise of sea level beneath a severe storm
Give the date of two storm surges from the last 60 years in eastern Uk
31st January 1953 floods and 6th December 2013 floods
How many died in the 2013 storm surge?
2 people
How many homes in Lincolnshire were flooded during the 2013 storm surge?
300
How many homes where advised to evacuate in Norfolk during the 2013 storm surge?
9000
How many homes in Kent were flooded during the 2013 storm surge?
500
Give an economic impact of the 2013 storm surge in Norfolk
Businesses were flooded
What counties were effected in the 1953 storm surge?
Lincolnshire, Norfolk, Suffolk and Essex
How many died in England in the 1953 storm surge?
307
How many had to be evacuated from their homes in the 1953 storm surge?
30,000
How many were made homeless by the 1953 storm surge?
40,000
Give 2 environmental impacts of the 1953 storm surge
Over 1600km of coastline was damaged and in Lincolnshire, flooding reached as far as 2 miles inland
Give to economic impacts of the 1953 storm surge
24,000 properties were seriously damaged and in 1958, damages cost £50 million
