1.b. Coastal landscape systems are influenced by a range of physical factors

Question 1

Physical factors influence coastal landscapes. How

Answer 1

These factors affect how coastal processes work and they operate over different spacial and temporal scales. These factors are often interrelated

Question 2

How does wind shape the coastline

Answer 2

• wind is the primary source of energy for a range of other processes e.g. erosion and transportation
• aeolian processes e.g. erosion and deposition, contribute to the shaping of coastal landscapes
• onshore winds drive waves towards the coast
• the higher the wind speed and the longer the fetch, the larger the waves and the more energy they possess

Question 3

How do waves shape the coastline

Answer 3

• waves are undulations on the surface of the sea driven by wind
• waves possess kinectic energy caused by the motion of moving water
• waves also possess potential energy

Question 4

What is the wave height

Answer 4

This is the difference between the crest and the trough. Wave height is directly proportional to the energy produced

Question 5

What is the crest

Answer 5

This is the highest point of the wave

Question 6

What is the trough

Answer 6

This is the lowest part of the wave

Question 7

What is the wave length

Answer 7

This is the distance between two crests

Question 8

What is the wave frequency

Answer 8

This is the number of waves per minute

Question 9

What are swell waves

Answer 9

These are waves that are formed in open oceans and travel over huge distances. They tend to have a long wave length with a wave period of up to 20 seconds

Question 10

What are storm waves

Answer 10

These are waves with a short wavelength, greater height and wave period of up to 5 econds

Question 11

What happens when waves enter shallow water

Answer 11

Wave enters shallow water which means friction with the seabed increases. The wave slows as it drags along the bottom. The wavelength drecreases amd successive waves start to bunch up. The wave increases in height andplumges or breaks onto the shoreline

Question 12

What are spilling waves

Answer 12

Steep waves breaking onto gentle sloping beaches. Water spills gently forward as the wave breaks

Question 13

What are plunging waves

Answer 13

Steep waves breaking into steep beaches. Water plunges vertically downward as the crest curls over

Question 14

What are surging waves

Answer 14

Low angle waves breaking onto steep beaches. The wave slides forward and may not actually break

Question 15

What is the swash

Answer 15

The wash of water up the beach

Question 16

What is the backwash

Answer 16

The drag back down the beach

Question 17

What are some properties of constructive waves

Answer 17

• low, long length (up to 100m)
• low frequency (6-8 mins)
• gentle spill onto shore
• the swash loses volume and momentum, leading to a weak backwash
• sediment movement off the beach is low
• swash energy exceeds backwash energy
• material is slowly and gradually moved up the beach
• form berms

Question 18

What are some properties of destructive waves

Answer 18

• high, steep frequency (10-14 per minute)
• rapid approach to shoreline
• little forward movement of the water
• powerful backwash-sediment is pulled away from the beach
• swash energy is less than backwash energy
• very little material is moved up the beach
• form storm beaches

Question 19

What is wave refraction

Answer 19

This is the process by which waves break onto an irregularly shaped coastline e.g. a headland separated by two bays

Question 20

Explain wave refraction

Answer 20

• waves drag in the shallow water approaching a headland
• wave becomes high, steep and short
• the part of the wave in the deeper water moves forward faster
• the wave bends
• the low energy wave spills into the bays as most of the wave enrgy is concentrated on the headland

Question 21

What are tides

Answer 21

The periodic fall of the sea surface and are produced by the gravitational pull of the moon and the sun

Question 22

How do tides work

Answer 22

• the moon pulls water towards it, creating a high tide
• there is a compnsating ‘buldge’ on the opposite side of the Earth
• at locations between the two buldges there is a low tide
• as the moon orbits the Earth and the high tides follow it
• the highest tides occur when the moon, earth and sun are aligned so gravitational pull is the stronngest
• resulting in spring tides with a high tidal range
• when the moon and sun are at angles to each other, gravitational pull is weak
• resulting in neap tides with a low range

Question 23

What is tidal range

Answer 23

This is the vertical difference in height between the consecuative high and low water over a tidal cycle. Tidal range influences where wave action occurs, the weathering processes, and the impact of processes between tides

Question 24

How does lithology influence coastal landscape systems

Answer 24

• lithology=chemical and physical structure of rocks
• this will impact on physical processes
• weak rocks e.g. clay erode faster than resistant rocks e.g. basalt
• chalk and limestone are susceptible to chemical weathering as their calcium carbonate content is soluble in weak acids

Question 25

How does structure affect the coastline

Answer 25

• structure refers to features of jointing, faulting and bedding planes in rocks and also their permeability
• permeable rocks include chalk and limestone
• structure affects the shape of the coastline-where rocks lie parallel to the coastline, it tends to be straight or concordant;where rocks lie at right angles to the coast, headlands adnd bays are formed-this is doscordant coastline
• structure affects ‘dip’ of rocks towards the coastline: lanward dipping rock layers lead to steep cliffs and for seaward-dipping tocks layers cliffs follow the angle of the dip

Question 26

What are currents

Answer 26

These are the permanent or seasonal movement of water in the seas and oceans. There are two types: longhsore and offshore

Question 27

How do currents affect the coastline

Answer 27

• rip (nearshore) currents transport coastal sediment. They are caused by tidal motion or waves breaking at right angles to the shore. Once rip currents form, they modify the shore profile by creating cusps which help perpetuate the rip current
• ocean (offshore) currents are generated by the Earth’s rotation and the currents are set in motion by the wind. Warm ocean currents transfer heat from low latitudes to high. This transfer affects air temperature and therefore sub-aeolian processes e.g. mass movement

Question 28

What are the factors that influence coastal landscape systems

Answer 28

• wind
• waves
• tides
• geology e.g. lithology and strructure
• currents