Destructive waves

1
Destructive waves

• In the foreground -what are the characteristics
  of the waves?
• This type of wave has lots of energy.

2
The effect of geology on coastal landforms and
processes

• Isle of Purbeck
• East Yorkshire Coast

3
The White Cliffs of Beachy Head

• The geology is visible - where is it weak?
• The power of the waves can attack these.
• At the foot of the cliff there is a rock shelf.
• What is this feature called?

4
Beachy Head, Sussex

• In this photo the bedding planes are clearer, as
  is the wave cut platform.
• On the top of these cliffs sub-aerial processes
  are at work.

5
Isle of Purbeck and Wight

• The Isle of Wight is chalk also.
• You can see the headlands of the Isle of Purbeck
  a peninsula not an island.
• How are these created?

6
Aerial view

• At what tide is this photograph taken?
• How do you know this?
• What features are visible?

7
Old Harrys Rocks

• The features are much easier to see here.
• Create an annotated sketch to show the main
  features.

8
Pinnacles at Old Harry

• What is this feature?
• What eventually will happen to this feature?
• Its a stack, eventually it will be undercut and
  will collapse to create a stump.
• The collapsed material will be used for attrition.

9
The East Yorkshire Coast

• This part of the coast line is called Holderness.
• Boulder clay or till is soft so it slumps easily.
  
• The finer clays are taken in to suspension.

10
1915

• Historically planners have not learnt to restrict
  building here the effects on the railway can be
  seen

11
Holderness

• Why would someone live here?
• Is there any protection to this beach?

12
South Holderness

• This is still the Holderness coastline why is
  there so little evidence of erosion at this time?
• The beach is performing a key role, which is the
  absorption of energy.

13
Holbeck Hotel, Scarborough

• Here we can see the more recent slump caused by
  heavy rain and saturated ground.
• The hotel collapsed in the middle of the night.
• The sea undermines the cliff, sub-aerial
  processes act on the top creating instability.

14
Summary

• Hard geology like the chalk cliffs of The Isle of
  Purbeck erode slowly forming caves arches and
  stacks. There is little chance of rapid erosion
  and therefore loss of infrastructure.

• Soft geology like the Holderness clay cliffs
  erodes quickly with slumping happening overnight.
  10m can be lost in one storm. Protection is
  needed in these areas

15
With thanks to

• Francine Wilson Jones, Wilnecote High School