Mass wasting:
The controlling factors of mass wasting include;
1.
The water content of the material.
2.
The temperature variation
3.
The angle of the slope
4.
The nature of the slope material
Various speeds of mass wasting:
Extremely slow soil creep 1cm a year
Very slow called solifuction
1m a year
Slow to moderate earth/ mudflow
1km a year
Rapid
1km an hour slumping
Very rapid
1m a second
Extremely rapid rockfalls
100m a second
Mass movements
Different mass movements occur on slopes under different conditions. We'll look at four types; rockfall, mudflow, landslip and soil creep.
Rockfall
Rockfall is the rapid, free-fall of rock from a steep cliff face. Rock fragments fall from the face of the cliff because of the action of gravity. This is made worse by freeze-thaw action loosening the rock. Bare, well-jointed rock is very vulnerable to rockfall - water enters the joint, freezes and expands, cracking the rock. A scree slope of fallen rock is formed at the bottom of the cliff.
Mudflow

Mudflow occurs on steep slopes over 10°. It's a rapid sudden movement which occurs after periods of heavy rain. When there is not enough vegetation to hold the soil in place, saturated soil flows over impermeable sub soil, causing great devastation and endangering lives.
Landslip / Slumping
Landslips or landslumps are occasional, rapid movements of a mass of earth or rock sliding along a concave plane. They can occur after periods of heavy rain, when the water saturates overlying rock, making it heavy and liable to slide. Undercutting of a steep slope by river or sea erosion weakens the rock above, also making a slump likely.
Soil creep
Soil creep is a very slow movement, occuring on very gentle slopes because of the way soil particles repeatedly expand and contract in wet and dry periods. When wet, soil particles increase in size and weight, and expand at right angles. When the soil dries out, it contracts vertically. As a result, the soil slowly moves downslope.
Be aware!
In the Core examination a standard question asks for both a description and explanation of the conditions and processes which have led to the formation of slopes affected by

mass movement. Remember that you will be penalised if you do not include both description and explanation.