Factors affecting coastal processes and landforms

Question 1

What factors decide wave type?

Answer 1

Wind velocity
Length of time wind has blown across water
Fetch

Question 2

How does wind velocity have an impact on wave type

Answer 2

Faster winds = bigger waves

Question 3

How does length of time wind has blown across the water have an impact on wave type

Answer 3

Longer periods of time produces bigger waves

Question 4

How does fetch have an impact on wave type

Answer 4

The greater the fetch the bigger the wave

Question 5

What is fetch?

Answer 5

Fetch is the distance the wind has blown over the water

Question 6

What can the orientation of a coastline do?

Answer 6

It an affect the impact a wave has.

e.g the orientation may protect it from high-energy waves.

Question 7

Why does wave refraction occur?

Answer 7

The wave direction approaching the shoreline is modified due to the shape of the seabed

Question 8

Wave refraction step 1

Answer 8

The depth of the water around a coastline varies. friction from the seabed in shallow water slows the progress of waves.

Question 9

Wave refraction step 2

Answer 9

Waves change direction so that they approach the coastline aligned parallel to it

Question 10

Wave refraction step 3

Answer 10

Step 2 distorts the spread of energy concentrated at headlands and dissipated in bays

Question 11

Wave refraction step 4

Answer 11

Concentrated energy at headlands encourages erosion. Lower energy in bays results in sediments deposited creating beaches.

Question 12

What is wave reflection

Answer 12

A wave hitting vertical surface such as a cliff face or sea wall bounces back without breaking or losing its energy.

Question 13

What are the lines of incoming and outgoing waves from vertical walls called?

Answer 13

Standing waves or the clapotis effect

Question 14

What are lithological factors

Answer 14

Rock type and structure that have an effect on processes and the landforms created

Question 15

How does the hardness of rock types have an impact on erosion?

Answer 15

Harder rocks are more resistant to erosion and so erode slowly often producing high cliffs.

Rocks such as clays and sandstone have less strength and so erode quicker, slumping is a dominant feature of this.

Question 16

What is slumping?

Answer 16

A slump is a form of mass wasting that occurs when a coherent mass of loosely consolidated materials or a rock layer moves a short distance down a slope

Question 17

How does the composition of a rock affect the rate of erosion?

Answer 17

The mineral composition affects the rate of weathering. For example sandstone is made of silica which is chemically inert. Which makes it have a low rate of chemical weathering

Feldspars in granite can be changed by hydrolysis into clay minerals decreasing the resistance to erosion

Rocks such as chalk and limestone have a calcium carbonate content that is suable in salt water making them erode much quicker.

Question 18

How does the structure of a rock affect the rate of erosion?

Answer 18

Rocks with many joints and bedding planes are weaker and more vulnerable to weathering and erosion.

Faults are major lines of weakness where erosion processes can have an even greater impact.

Folding weakens rocks and affects the dip of rock strata influencing the rate of erosion and cliff profiles.