Wave And Sea Levels

Question 1

What are high energy coastlines?

Answer 1

High-energy coastlines are associated with more powerful waves, so occur in areas where there is a ​large fetch. They typically have ​rocky headlands and landforms and fairly frequent ​destructive waves​. As a result these coastlines are often eroding as the rate of erosion exceeds the rate of deposition​.

Question 2

What are low energy coastlines?

Answer 2

Low-energy coastlines have less powerful waves and occur in ​sheltered areas where constructive waves prevail and as a result these are often ​fairly sandy areas​. There are landforms of deposition​ as the rates of ​deposition exceed the rates of erosion

Question 3

What does the size of the wave depend on?

Answer 3

The size of a wave depends on various factors including:
- The ​strength​ of the wind
- How long the ​wind​ has been blowing for
- Water depth
- Distance of ​fetch

Question 4

What are the features of constructive waves?

Answer 4

▪ Strong swash, weak backwash
▪ Low wave height, long wavelength
▪ Low frequency
▪ Depositional

Question 5

Features of destructive waves?

Answer 5

▪ Strong backwash, weak swash
▪ High wave height, short wavelength
▪ High frequency
▪ Erosional

Question 6

What can cause short term sea level change?

Answer 6

• High tide and low tide​ ​- a daily phenomena due to the gravitational pull of the Moon.
• Wind strength and direction​ - these can change causing a change in sea level for a couple of minutes or longer
• Atmospheric pressure​ - the lower the pressure, the higher the sea levels.

Question 7

What can cause long term sea level rise?

Answer 7

Isostatic​ - ​localised sea level change
Isostatic sea level change could be due to ​post-glacial adjustment​ ​(glaciers weigh down the land beneath, and so the land subsides until it melts).

Tectonic activity​ (such as ​earthquakes​ and ​volcanic eruptions​) may cause land subsidence, therefore causing isostatic sea level increase.

Eustatic rise - Global sea level change
Eustatic rise is due to ​thermal expansion.​ Water expands when it gets warmer, and so the volume of water increases which as a result, sea levels increase. This is due to​ ​Global Warming​.