Unit 3.1-3.2

Question 1

What is a landslide?

Answer 1

A landslide is the collapse of slope when mass of soils and rock of all sizes, move down a slope rapidly due to gravity

Question 2

Which two areas do landslides usually occur on?

Answer 2

Natural terrain and man-made slopes

Question 3

Give four ways as to how landslides affect us

Answer 3

They cause injuries and death. They also bury buildings they damage infrastructure and they block roads and stop traffic.

Question 4

What are the two factors affecting the slope stability

Answer 4

Driving force resisting force

Question 5

What is a driving force and what does it consist of?

Answer 5

Driving for pool slope is down due to the force of gravity. It consists of the slope gradient and the weight of slope materials.

Question 6

What is the resisting force and what does it consist of?

Answer 6

The resisting force prevents slope materials from sliding down it consists of cohesion, and friction

Question 7

When will landslides occur?

Answer 7

Landslides occur when the travel force is greater than the resisting force

Question 8

What are the three natural causes of landslide?

Answer 8

Heavy rainfall, strong weathering and large slope gradient

Question 9

Explain how heavy rainfall causes landslide

Answer 9

Landslides in Hong Kong occurred during the wet summer months rainfall adds much weight to the slope and the driving force increases. Therefore slope materials are more likely to fall down at the same time rainwater seep into the soil and slopes and this reduces cohesion and reduces friction as well. This will lead to a decrease in the resisting force.

Question 10

Explain how strong weathering causes landslide

Answer 10

Weathering refers to the wearing weight or breakdown of rocks. Many areas in Hong Kong are made up of granite and granite is easily weathered under hot and wet climate. This will leave a thick layer of loose materials on the slope and the resisting force of these loose materials is small, therefore landslide occurs

Question 11

Explain how large slope gradient causes landslide

Answer 11

Hong Kong has hilly and steep slopes, the steeper, the slope, the stronger the influence of gravity. Therefore the driving force increases and this will lead to the risk of landslide