Mass Movement

Front 1

Regolith

Back 1

Loose weathered/eroded rock

Front 2

What is mass movement?

Back 2

The process of material brought down a slope by gravity

Front 3

Name and explain the factors which affect mass movement

Back 3

Gradient: the steepness of the slope

Vegetation: the roots of plants and trees maintain stable soil

Front 4

Name the different forms of mass movement and state which forms are slow or fast

Back 4

Soil creep:Slow

Bog bursts,mudflows,avalanche, landslide: fast

Front 5

Define soil creep

Back 5

Movement of regolith down a slope due to gravity, slowest form of mass movement and can be identified by the terracettes it creates

Front 6

Define bog bursts

Back 6

Occurs when a mass of bog/peat moves down a slope after a period of heavy rainfall. Peat becomes saturated and flows down hill

Front 7

Define mudflows

Back 7

Occurs when regolith and soil become saturated with water, fastest form of mass movement, occurs after periods of heavy rainfall or after volcanic eruption as the heat causes snow and ice in upland areas to melt forming water which brings the soil and rock downhill. This second type is particularly dangerous because ash is also mixed,this is called a lahar.

Front 8

Name a case study of a lahar mudflow

Back 8

Nevada del Ruiz in the Andes mountains in Colombia, night of 13th November 1985, over 23000 people killed

Front 9

Define landslide

Back 9

Rapid movement of regolith down a slope that has become steep and unstable, causes include: coastal erosion, deforestation, earthquakes and undercutting

Front 10

Avalanche

Back 10

Rapid movement of snow and ice downhill when the weight of the material is too much for the slope to hold