Waves And Deposition

Question 1

What is the wave period?

Answer 1

The time that it takes for two successive waves to pass a particular point.

Question 2

What is the wave frequency?

Answer 2

The number of waves per minute.

Question 3

What factors influence how big waves are?

Answer 3

1) How strong the wind is
2) How long the wind blows for
3) How long the fetch is
4) The depth

Question 4

Why do waves break?

Answer 4

When the waves near the coast the bottom of the wave is slowed by friction with the seabed. The speed of the waves depends on the depth. Because the top of the wave is experiencing less friction it topples over the bottom of the wave and breaks.

Question 5

What is swash?

Answer 5

The movement of water up the beach.

Question 6

How is the direction of swash determined?

Answer 6

It is determined by the direction of the wind.

Question 7

What is backwash?

Answer 7

The movement of water back down the beach.

Question 8

What is the direction of backwash determined by?

Answer 8

Gravity.

Question 9

What are destructive waves?

Answer 9

1m+ waves with weak swash and a strong backwash and erodes material from the beach. They also have a high frequency (10-12 waves per minute).

Question 10

What are constructive waves?

Answer 10

Waves less than 1m tall with a strong swash but a weak backwash. Constructive waves deposit materials on the beach. They also have a relatively low frequency (6-8 waves per minute).

Question 11

What is longshore drift?

Answer 11

Longshore drift is where a waves hits a beach at an angle. The direction of waves and swash is determined by the prevailing wind direction. The wave carries sediments up and along the beach and then the back wash flows straight back down the beach. Overtime sediment is moved along the beach.

Question 12

How does a spit form?

Answer 12

Longshore drift happens in the direction of the prevailing wind. When the coast bends longshore drift does not stop and continues out into the sea. If the sea has low energy and deposition is greater than erosion, overtime a spit will build up. The end of the spit is usually hooked due to a storm.

Question 13

What is a spit?

Answer 13

A spit is a long, thin stretch of sand connected to the mainland but stretching out into the sea. Spits are formed in areas of calm water where the sea has less energy.

Question 14

How is a marsh formed?

Answer 14

Salt marshes are typically found behind spits, in estuaries or on long energy coastlines. Because they have low energy, deposition is greater than erosion, so over time mudbanks are formed.
Cord grass often grows in these salt marshes.

Question 15

What is a bar?

Answer 15

A bar is a spit that connects two headlands or runs across the mouth of a small bay.

Question 16

Where is an example of a bar?

Answer 16

Slapton bay, UK

Question 17

What is a tombolo?

Answer 17

A spit that joins the mainland with an island.

Question 18

What is a beach?

Answer 18

A beach is the accumulation between the lowest neap tide and the highest spring tide.

Question 19

Where do beaches get their material from?

Answer 19

Beaches get their material from: longshore drift, constructive waves, cliff erosion and river sediments.

Question 20

What is a sand dune?

Answer 20

A sand dune is a depositional feature.

Question 21

How are sand dunes created?

Answer 21

Sand dunes are created when vegetation succession and aeolian transport interact (work together).

Question 22

What is vegetation succession?

Answer 22

Vegetation succession is a biological concept where plants succeed (outgrow) smaller plants until a climax community is reached.

Question 23

What is aeolian transport?

Answer 23

Aeolian (wind) transportation is the movement of sand by the wind.

Question 24

What is saltation?

Answer 24

Saltation is where grains of sand ‘bounce’ in the wind.

Question 25

What is traction?

Answer 25

Traction is where grains of sand ‘roll’ in the wind.

Question 26

What is a pioneer species?

Answer 26

Spinifex. Spinifex catch sand by slowing the wind.

Question 27

What are small starting sand dunes called?

Answer 27

Embryo dunes.

Question 28

What plants are found on sand dunes?

Answer 28

Marram grass and knobby club rush.

Question 29

Where is an example of sand dunes in New Zealand?

Answer 29

Muriwai beach, West coast.

Question 30

What materials can beaches be made out of?

Answer 30

Beaches could be made out of sand, shingle and/or pebbles.

Question 31

What does the CASH acronym stand for?

Answer 31

C - corrasion
A - attrition
S - solution
H - hydraulic pressure

Question 32

What is corrasion?

Answer 32

Corrasion is rocks being thrown into cliffs by waves and when they break bits off the cliff.

Question 33

What is attrition?

Answer 33

Rocks, sand and stones being thrown into each other by the sea current and waves.

Question 34

What is solution?

Answer 34

The slight acidity of sea water causing bits of the cliff to dissolve.

Question 35

What is hydraulic pressure?

Answer 35

Where sea water and air become trapped in cracks in a cliff. The increasing pressure causes the rock to crack.

Question 36

What is wave pounding?

Answer 36

Wave pounding is where waves crashing into cliffs cause them to become weaker.

Question 37

Where is an example of a headland?

Answer 37

At Otakamiro point.

Question 38

Where is an example of a stack?

Answer 38

At Motutara stack.

Question 39

Where is an example of a stump?

Answer 39

At Daia island.

Question 40

How are coves formed and what are they?

Answer 40

Coves are a costal feature that is formed when rock along the coastline has a varying hardness.

Question 41

What is an example of a cove?

Answer 41

Lulworth cove, Dorset, England.

Question 42

What conditions does coral need to form?

Answer 42

1) Tropical conditions
2) Water 20C to 30C roughly
3) Unpolluted and clean water
4) Sunlight
5) Water less than 50 metres deep
6) Saltwater

Question 43

What is wave refraction?

Answer 43

Wave refraction is a process which amplifies other wave erosion processes. It is also where waves ‘bend’ around the headland.