2.5. Coastal Erosion

Question 1

What is hydraulic power?

Answer 1

• The sheer force of the water hitting the rocks.
• When a wave advances, air can be trapped and compressed, either in joints in rock or in between breaking wave and cliff. When the wave retreats, compressed air expands. Continuous processes can weaken the joints and cracks in the cliff, causing pieces of rock to break off.

Question 2

What is cavitation?
(part of hydraulic power)

Answer 2

• Bubbles om water may implode under high pressure which generates tiny jets of water which will erode rock over time

Question 3

What does hydraulic power depend on?

Answer 3

Season- stronger in winter

Larger fetch means it will be stronger

Question 4

What is abrasion?

Answer 4

• Corrasion hurls sediment at a cliff face
• Involves a sandpapering effect as sediment is dragged up and down or across the shoreline, eroding and smoothing rocky surfaces.
• Important in the formation of a wave cut platform

Question 5

What is wave quarrying?

Answer 5

• The action of waves breaking against unconsolidated material, such as sands and gravels.
• Waves scoop out the loose material in a similar way to the action of a giant digger

Question 6

What is corrasion?

Answer 6

• When waves advance, they pick up sand and pebbles from the sea bed. When they break at the base of the cliff, the transported material is hurled at the cliff foot, chipping away rock.
• Depends on size, shape and amount of sediment picked up by waves, along with wave type - determines importance

Question 7

What is solution (corrasion)?

Answer 7

• Weak acids in sea water can dissolve alkaline rock, or the alkaline cement that bonds rock particles together.
• Action of solution may be indistinguishable from the action of carbonation

Question 8

What is attrition?

Answer 8

• Not directly responsible for eroding a coastline. Gradual wearing down of rock particles by impact and abrasion as pieces of rock are moved by waves, tides and currents- rounder and smoother stones