Mass Movement Case Studies for OCR Geography A2 Level

Mass Movement

Watford Junction 2016 MEDC

Trigger

Heavy rainfall increases sheer stress and then causes landslide

Background

Victorian embankment- old and not porous so traps water increasing sheer stress

Built at over 35 degrees which is too steep, thus more likely to decrease sheer strength

Saturated soils

CHALK POROUS GEOLOGY

Impact

Social

2 injured

Psychological damage of train crash

Delays and diversions until track repaired

Economic

Line repair costs

Environmental

None really

Responses

Suspend trains immediately but not quick enough to prevent crash

Emergency services come out to help

Embankment replaced

Galtur, West Austria, 1991 MEDC

Trigger

Power avalaunche: so lots of snowfall increasing sheer stress

4m of snowfall

Background

Some protection in place: like zoning and other defences but not enough

Deforestation so prevents consolidation reducing sheer strength

3 storms where atlantic and artic air clashes so produces snowfall

Impact

Social

Deaths

 

Economic

£5M/day of closure for all the resorts

Environmental

None, really; because of nature of environment- apart from increasing vehicle activity in area to free people=pollution

Responses

Emergency chopper and dogs

Steel poles to break up packed snow next time

Better forecasting

Relocation of safety zoning

 

Las Colinas El Salvador, Central America MUDSLIDE 2001 LEDC

Trigger

Earthquake 7.5 vibrations and shock increases sheer stress

Background

Deforestation prevents consolidation

People stupidly build at bottom of unstable hill

Lack of forecasting or prediction

Winter rain saturates hill

Impact

Social

585 deaths

Displacement

Homes destroyed

Economic

Businesses destroyed

$7M worth of water supply damaged

Environmental

Pollution due to water supply damage

Responses

Emergency services help

 

 

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