Fig. 1 shows a coastal cliff at Lydon Bay after three days of intense rainfall. A geography class observed the site from a safe viewpoint during a fieldwork...
Question 1 Report
Fig. 1 shows a coastal cliff at Lydon Bay after three days of intense rainfall. A geography class observed the site from a safe viewpoint during a fieldwork enquiry. The diagram shows water entering cracks in the rock and a section of material that has moved downslope. The council is considering whether to close the footpath at the base of the cliff.
(a) State the type of mass movement shown in Fig. 1. [1]
(b) Explain how heavy rainfall can make a landslide more likely. [2]
(c) State two ways the council could reduce danger to people using this coastal path. [2]
Answer Details
(a) The mass movement is a landslide. Slumping is also accepted. [1]
(b) Rainwater soaks into the cliff material, increasing its weight. Water can also reduce friction along a slip surface, effectively lubricating it, so gravity is more able to move the material downslope. [2]
(c) Two suitable measures are to close or divert the footpath away from the cliff base and to install warning signs or barriers. Improving drainage, stabilising the slope with netting, bolts or retaining structures, and monitoring movement are also valid. [2]
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