Coastal Processes Flashcards
What are the four main processes of coastal erosion?
Solution, abrasion, hydraulic action, attrition
These processes describe how coastal features are modified and eroded over time.
What is solution in coastal erosion?
When destructive waves pick up beach material and hurl them at the base of a cliff, forming a wave-cut notch
This process involves the physical impact of waves on cliff material.
What is abrasion in the context of coastal erosion?
The wearing away of the base of a cliff or headland by breaking waves containing sand and larger fragments
This process is also referred to as the sandpaper effect.
Why is abrasion particularly common in high-energy storm conditions?
Because breaking waves are more forceful and contain more abrasive materials
High-energy conditions enhance the impact of waves on coastal structures.
What occurs during hydraulic action?
Air is compressed in cracks and joints of cliffs, leading to explosive effects when pressure is released
This process can cause significant erosion and material break-off from cliffs.
What is the role of weathering in hydraulic action?
It weakens the material, making it more susceptible to being broken off by the explosive effects of air pressure changes
Weathering complements hydraulic action by destabilizing cliff structures.
What is attrition in coastal erosion?
When waves cause rocks and pebbles to bump into each other and break up
This process gradually reduces the size of beach materials.
What is coastal erosion most significant when waves have?
A large fetch
Example: The south-west coast has an 8000 kilometre fetch across the Atlantic Ocean.
What atmospheric condition contributes to significant coastal erosion?
Strong winds blowing for a long time
This creates destructive waves.
How does the absence of a beach affect coastal erosion?
It allows waves to hit the coastline directly
An area of coastline with no beach has no buffer for the waves.
What type of cliff material contributes to high rates of erosion?
Soft materials, such as soft boulder clay
Example: The Holderness Coast experiences the highest rate of erosion in Europe.
What structural feature of cliffs can increase erosion rates?
Many joints in the rock
Joints can allow waves to penetrate and erode the rock more easily.
What is the effect of wave refraction on coastal landforms?
Waves converge on headlands
This process can intensify erosion on headlands.
What is coastal transportation?
The movement of material in the sea and along the coast by waves.
What is the movement of material along the coast called?
Longshore drift.
What are the four different ways material moves along the coast?
- Traction
- Saltation
- Suspension
- Solution
What does traction involve?
Large pebbles and boulders being rolled along the sea bed.
What type of waves are most likely to transport material by traction?
High energy destructive waves.
What does saltation involve?
Small stones, pebbles, and silt being bounced along the sea bed.
What types of waves can move material by saltation?
Both destructive and constructive waves.
What is transportation by suspension?
Fine particles of clay and sediment are suspended in the sea and transported by waves.
What types of waves can transport material by suspension?
Both destructive and constructive waves.
What does it mean when material is transported in solution?
Material is dissolved and carried by the sea.
What is longshore drift?
The movement of material along the shore by wave action.
How does longshore drift occur?
It happens when waves approach the beach at an angle.
What is swash in the context of longshore drift?
Waves moving up the beach that carry material up and along the beach.
What is backwash in the context of longshore drift?
Waves moving back down the beach that carry material back down at right angles.
What causes backwash to move material back down the beach?
Gravity.
What link does longshore drift provide between erosion and deposition?
It slowly moves material along the beach.
What type of landforms does longshore drift contribute to forming?
Depositional landforms such as spits and onshore bars.
