Mass Movement

Question 1

What is mass movement?

Answer 1

Mass movement refers to loose weathered materials (regolith) that moves down slopes under the influence of gravity.

Question 2

Causes of mass movement 

Answer 2

Construction of roads and rails - this undercut slopes making them unstable and steeper leading to mass movement e.g Rockfall
Steeper slopes (gradient) increases the likelihood of mass movement
Water content - see pitch after heavy rainfall connectors in lubricant making materials more likely to slide. Water also adds weight to the slope.
Vegetation cover - roots help blind soil together and trees also absorb much of water deforestation increases the risk of mass movement
Earthquakes/volcanic activity - seismic activity

Question 3

Soil creep

Answer 3

Soil creep is a slow form of mass movement. It occurs the soil move very slowly down gentle slopes at the speed of about 1 cm a year.
this is the slowest form of mass movement. We only noticed this effects on the landscape from the close that leaves after many years. E.g terracettes in the land. Broken fences. A soil build up behind the wall.

Question 4

Landslides

Answer 4

Happen when huge amounts of dry regolith slide downhill at speed destroying everything in their path. Usually something has caused the slope to become unstable, e.g rainfall, deforestation, undercutting by roadbuilding or sea erosion in some cases, earthquakes may trigger many landslides across the area.

Question 5

This 2018 Southern California landslide

Answer 5

23 people were killed
It was caused by heavy rainfall after the Thomas forest fires