Case study for cliff collapse

Question 1

What is the case study for cliff collapse (coastal erosion) and when did it occur?

Answer 1

Holbeck Hall, Scarborough, Summer 1993

Question 2

Why did it happen?

Answer 2

During the summer of 1993,
-there was a long period without rain,
-followed by a period with heavy rainfall, therefore the water was able to penetrate through the sand/gravel making up the cliff to become saturated.
-The rainfall reached 140mm in 2 months before the slumping occurred and acted as a lubricant which made the material more slippy and prone to collapse.
-The material consisted of glacial till which is a mixture of sandy, silty clay. This meant the resistance of the rock was weak as fragments were able to slide over each other.
Pore water pressure was built up as the force between the particles and surface reduced, decreasing the overall resistance