Coastal processes

Question 1

How are waves created?

Answer 1

When the wind blows over the sea.

Question 2

What factors does the size and energy of a wave depend on?

Answer 2

the fetch
the strength of the wind
how long the wind has been blowing for

Question 3

What is the fetch of a wave?

Answer 3

How far the wave has travelled.

Question 4

What are the different types of wave?

Answer 4

Constructive and destructive

Question 5

What determines the type of wave?

Answer 5

The energy of the swash and backwash.

Question 6

What is the swash?

Answer 6

The water that rushes up the beach when a wave reaches the shore.

Question 7

What is the backwash?

Answer 7

The water that flows back towards the sea.

Question 8

What is a destructive wave?

Answer 8

Waves which remove material from the beach. The swash is weaker than the backwash.

Question 9

What are the characteristics of a destructive wave?

Answer 9

weak swash and strong backwash
the strong backwash removes sediment from the beach
the waves are steep and close together

Question 10

What is sediment?

Answer 10

Small fragments of rock and soil that form layers.

Question 11

What is a constructive wave?

Answer 11

Waves which help build up material on the beach. They tend to have a low frequency and strong swash.

Question 12

What are the characteristics of a constructive wave?

Answer 12

strong swash and weak backwash
the strong swash brings sediments to build up the beach
the backwash is not strong enough to remove the sediment
the waves are low and further apart

Question 13

When does freeze-thaw weathering occur?

Answer 13

when rocks are porous (contain holes) or permeable (allow water to pass through)

Question 14

What does porous mean?

Answer 14

contains holes

Question 15

What does permeable mean?

Answer 15

allows water to pass through

Question 16

What is the process of freeze-thaw weathering?

Answer 16

1. Water enters cracks in the rock.
2. When temperatures drop, the water freezes and expands causing the crack to widen.
3. The ice melts and water makes its way deeper into the cracks.
4. The process repeats itself until the rock splits entirely.

Question 17

What is the process of biological weathering?

Answer 17

1. Plant roots can get into small cracks in the rock.
2. As the roots grow, the cracks become larger.
3. This causes small pieces of rock to break away.

Question 18

What is chemical weathering?

Answer 18

Rainwater and seawater can be a weak acid. If a coastline is made up of rocks such as limestone or chalk, over time they can become dissolved by the acid in the water.

Question 19

What types of weathering are there?

Answer 19

freeze-thaw, biological and chemical

Question 20

What are the four different types of mass movement?

Answer 20

rockfall, mudflow, landslide, rotational slip

Question 21

What is mass movement?

Answer 21

A large-scale downward movement of rocks and material.

Question 22

What is a rockfall?

Answer 22

When bits of rock fall off the cliff face, usually due to freeze-thaw weathering.

Question 23

What is a mudflow?

Answer 23

When saturated soil (soil filled with water) flows down a slope.

Question 24

What is a landslide?

Answer 24

When large blocks of rock slide downhill.

Question 25

What is a rotational slip?

Answer 25

When saturated soil slumps down a curved surface.

Question 26

What is erosion?

Answer 26

the wearing away of rock along the coastline

Question 27

What is hydraulic action?

Answer 27

This is the sheer power of the waves as they smash against the cliff. Air becomes trapped in the cracks in the rock and causes the rock to break apart.

Question 28

What is abrasion?

Answer 28

This is when pebbles grind along a rock platform, much like sandpaper. Over time the rock becomes smooth.

Question 29

What is attrition?

Answer 29

This is when rocks that the sea is carrying knock against each other. They break apart to become smaller and more rounded.

Question 30

What is solution?

Answer 30

This is when sea water dissolves certain types of rocks. In the UK, chalk and limestone cliffs are prone to this type of erosion.

Question 31

What are the types of transportation?

Answer 31

solution, suspension, saltation and traction

Question 32

What is solution?

Answer 32

When minerals in rocks like chalk and limestone are dissolved in sea water and then carried in solution. The load is not visible.

Question 33

What is suspension?

Answer 33

Small particles such as silts and clays are suspended in the flow of the water.

Question 34

What is saltation?

Answer 34

Where small pieces of shingle or large sand grains are bounced along the sea bed.

Question 35

What is traction?

Answer 35

Where pebbles and larger material are rolled along the sea bed.

Question 36

What is longshore drift?

Answer 36

The movement of material along a coastline due to the angled approach of waves.

Question 37

What happens in longshore drift?

Answer 37

Waves approach the coast at an angle because of the direction of prevailing wind. The swash will carry the material towards the beach at an angle. The backwash then flows back to the sea, down the slope of the beach. The process repeats itself along the coast in the zigzag movement.

Question 38

What is deposition?

Answer 38

When the sea loses energy and it drops/deposited the material it has been carrying.

Question 39

What type of waves are needed for deposition to occur?

Answer 39

constructive waves

Question 40

What are factors that can lead to deposition?

Answer 40

waves starting to slow down and lose energy shallow water sheltered areas, eg bays little or no wind