3.4.2.8 Mass movement
Human causes and consequences
of
mass movement
1. Recognize and understand human causes of mass
movement:
– Deforestation
– building on steep gradients
– road construction
– other activities that cause slope instability.
2. Use a specific case study to illustrate the
consequences and responses to a contemporary
example of human -induced mass movement.

Human influence
• People can alter the balance of conditions on a
hillslope in many ways such as by undermining the
slope by:
– mining and quarrying,
– excavation for a building site, road or pipeline
– terracing land for farming
• Instability may also be increased by adding a load
such as spoil from an excavation to the top of a slope.
• Cutting timber decreases slope stability – forests
may be cut down for firewood or to make way for
agriculture Trees help stability by adding root
strength to the soil and by transpiring excess water..
Deforestation encourages more surface run off and soil

Human triggers
• Individual landslides may be caused by a
number of factors (active causes), and
there may be triggering mechanisms
such as:
– Blasting (human)
– vibration caused by traffic (human)

Other human causes…
Filling a reservoir may also lead to bank
saturation and land sliding.
The construction of dams can trigger
landslides and earthquakes as the
weight of the water depresses the rock
strata under the lake.

How can slopes be stabilised?
• Plant vegetation to bind the soil together and
intercept rainfall
• Improve drainage to prevent the slope
becoming saturated and to stop lines of
weakness for example bedding planes
becoming lubricated
• Use wire nets and metal stakes to hold a
slope together
• Reduce the gradient by adding material to
the base of a slope.

Case study
Deadly landslide hits Indonesia 12.01.07
http://news.bbc.co.uk/1/hi/world/asia-pacific/6254469.stm
Indonesia landslides bury dozens 26.12.07
http://news.bbc.co.uk/1/hi/world/asia-pacific/7160138.stm
Indonesian landslide toll mounts 27.12.07
http://news.bbc.co.uk/1/hi/world/asia-pacific/7161480.stm
Two dead in Indonesia landslide 6.2.08
http://news.bbc.co.uk/1/hi/world/asia-pacific/7229813.stm

Case studies of Human
mismanagement….
Ref Waugh page 54 / 55
(b) Building dams to create reservoirs – Italy
1963
(c) Dumping waste material – Aberfan 1966
(d) Urbanisation – Hong Kong 1948 - 1998

Task ….
• Complete question 6 Waugh page 57

Exam Q 2008
The table below shows some of the factors that affect the probability of
rapid mass movements.
Natural factors Human factors
Snow melt Deforestation
Weathering Traffic vibration
Slope angle Road construction
Rock type / structure Loading slopes with
waste material
Seismic activity Addition of water
Factor A Factor B
Identify factors A and B
Select one natural and one human factor from the table (excluding
factors you chose for A and B and explain how each contributes to slope
instability (4 marks)
Using a specific case study, examine the causes, consequences and
responses to a rapid mass movement influenced by human activity. (10
marks)

May 05
‘Slope instability is entirely due to human
activity.’
Using examples, assess this statement
Waugh pg 57 Q9
Using case studies from a range of
environments, explain how an understanding of
natural processes can be used in planning
urban developments