Rocks and weathering
The human impact result in mass movement on slopes
Case study: Merriespruit tailings dam disaster, Virgina, South Africa
Human Excavation and loading by water (drainage was disturbed)
Cause Gold is extracted at very low purities, and the process produces large
quantities of fine-grained waste mixed with water known as tailings
Loaded as ‘slime dams’ which is a key feature in this area - rectangular,
steep-sided, flat-topped hills
Dam was constructed to help drain away surplus of water
22nd February 1994 - thunderstorm of 50mm of rain in 30 mins = dam failed
and 600,000m3 of liquid flowed 4km away from the dam
Impacts 250 houses in the suburb
Nearest house was 300m away from the dam
Wave of water 2.5m high
Environmental damage, 17 people killed, 80 houses destroyed
How human activity can result in erosion on slopes - soil left loose and prone to wind and rain
Case Railway landslide in Cumbria UK - 1995. The line from Settle and Carlisle
study:
Causes Railway cutting on an area where shales and sandstone and
alternating impermeable and permeable rock making it prone to
slippage
Heavy rain on the hill side caused a train to be derailed
Impacts Train was derailed = 1 death of the conductor from an oncoming train
31st of January 1995
Hong Kong attempts to reduce mass movement
Human causes to Rapid urbanisation = high density buildings on steep
being vulnerable to slopes e.g luxury homes on the Redhill Peninsula
mass movement 1972 Po Shan Road Landslide - occurred due to slope
cutting and water infiltration
Removal of vegetation for development
Physical causes to Over 60% of Hong Kong’s land area consists of steep
being vulnerable to slopes exceeding 20 degrees
mass movement Receives average rainfall of 2,400mm
Predominant rock types: Granite (prone to deep chemical
weathering). And volcanic tuff (weathers into clay-rich
soils) creating thick layers of weathered regolith
Strategies to manage Controlling excess water from tropical climate and typhoons
mass movement Since 1995, city has invested $3.8B into projects such as
The human impact result in mass movement on slopes
Case study: Merriespruit tailings dam disaster, Virgina, South Africa
Human Excavation and loading by water (drainage was disturbed)
Cause Gold is extracted at very low purities, and the process produces large
quantities of fine-grained waste mixed with water known as tailings
Loaded as ‘slime dams’ which is a key feature in this area - rectangular,
steep-sided, flat-topped hills
Dam was constructed to help drain away surplus of water
22nd February 1994 - thunderstorm of 50mm of rain in 30 mins = dam failed
and 600,000m3 of liquid flowed 4km away from the dam
Impacts 250 houses in the suburb
Nearest house was 300m away from the dam
Wave of water 2.5m high
Environmental damage, 17 people killed, 80 houses destroyed
How human activity can result in erosion on slopes - soil left loose and prone to wind and rain
Case Railway landslide in Cumbria UK - 1995. The line from Settle and Carlisle
study:
Causes Railway cutting on an area where shales and sandstone and
alternating impermeable and permeable rock making it prone to
slippage
Heavy rain on the hill side caused a train to be derailed
Impacts Train was derailed = 1 death of the conductor from an oncoming train
31st of January 1995
Hong Kong attempts to reduce mass movement
Human causes to Rapid urbanisation = high density buildings on steep
being vulnerable to slopes e.g luxury homes on the Redhill Peninsula
mass movement 1972 Po Shan Road Landslide - occurred due to slope
cutting and water infiltration
Removal of vegetation for development
Physical causes to Over 60% of Hong Kong’s land area consists of steep
being vulnerable to slopes exceeding 20 degrees
mass movement Receives average rainfall of 2,400mm
Predominant rock types: Granite (prone to deep chemical
weathering). And volcanic tuff (weathers into clay-rich
soils) creating thick layers of weathered regolith
Strategies to manage Controlling excess water from tropical climate and typhoons
mass movement Since 1995, city has invested $3.8B into projects such as
