Living With The Physical Environment - Natural Hazards Flashcards

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1
Q

Natural Hazards

A

A natural event that poses as a threat to humans and/or property

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2
Q

Atmospheric hazards

A

Tornadoes

Droughts

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3
Q

Geological hazards

A

Earthquakes

Volcanoes

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4
Q

Flooding hazards

A

Avalanches

Tsunami’s

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5
Q

Hazard risk

A

Chance of being affected by a natural hazard

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6
Q

Factors affecting risk

A

Urbanisation

Poverty

Farming

Climate change

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7
Q

Earthquakes

A

A sudden or violent movement within the earth crust

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8
Q

Volcano

A

An opening in a planets crust through which molten rock, hot gases, and other materials erupt

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9
Q

Convection currents

A

Heat-driven cycles that occur in the mantle

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10
Q

Constructive plate margins/boundaries

A

Two plate boundaries move apart

As a gap appears magma forces its way upwards breaking through the overlying crust

This causes earthquakes

E.g. Azares

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11
Q

Destructive plate margins/boundaries

A

Two plates are moving towards each other

The oceanic plate is subducted beneath the continental plate

Friction is built up and released through an earthquake

The continental plate melts, forming magma that breaks through the surface to form a steep-sided volcano

E.g. Andes

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12
Q

Collision plate margins/boundaries

A

Two plates are moving towards each other

The two plates collide and the crust uplifts forming folded mountains

This process causes earthquakes

E.g. San Andreas Fault

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13
Q

Conservative plate margins/boundaries

A

Two plates move past each other

Friction causes earthquakes

E.g. The Himalayas

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14
Q

Nepal case study - Facts

A

Date - 25/4/2015

Magnitude - 7.9

Plate boundary - destructive

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15
Q

Nepal case study - Primary effects

A

Social - 9000 died, 20000 injured, 8 million (1/3 of the population) affected

Economic - cost $5 billion, 50% of shops destroyed

Environmental - no power or water supplies

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16
Q

Nepal case study - Secondary effects

A

Social - avalanche in Langtang region left 250 people missing

Economic - roads blocked

Environmental - landslide/avalanche killed 19 people

17
Q

Nepal case study - Immediate responses

A

Roads repaired

Landslides cleared

1/2 million tents provided

18
Q

Nepal case study - Long term responses

A

30000 migrated

Repairs to Everest base camp

7000 schools repaired

19
Q

Chile case study - Facts

A

Date - 27/2/2010

Magnitude - 8.8

Plate boundary - destructive

20
Q

Chile case study - Primary effects

A

Social - 500 died, 12000 injured, 800000 affected

Economic - cost $30 billion, 220000 homes destroyed

Environmental - no power, no water supplies

21
Q

Chile case study - Secondary effects

A

Social - coastal towns destroyed by waves

Economic - 1500km of roads destroyed, remote communications cut off

Environmental - Pacific countries were hit by tsunamis

22
Q

Chile case study - Immediate responses

A

Field hospitals

$60 million for emergency shelters

Power + water restored

23
Q

Chile case study - Long term responses

A

4 years to fully recover

Economy was rebuilt

Housing reconstruction plans

24
Q

Why do people choose to live in hazardous areas?

A

Poverty - cannot afford to move (V+E)

Location - want to live near family or friends (V+E)

Fertile soil and minerals - agricultural benefits, rocks = construction materials for buildings (V) (Used in Iceland - case study)

Geothermal energy - provides 90% of energy/electricity (V) (Used in Iceland - case study)

Monitoring - scientists can accurately tell when a disaster is going to happen through seismometers and animal behaviour (V+E)

Frequency - volcanoes don’t erupt everyday, large earthquakes are rare (V+E)

25
Q

Reducing the risk - Earthquakes

A

Monitoring - earthquakes cannot be predicted

Prediction - no clear warning signs

Protection - walls are reinforced in steel, shock absorbers to absorb shaking, tsunami walls (protect people and important buildings e.g. nuclear power station)

Planning - use hazard maps as they the areas most likely to be affected and they can be evacuated

26
Q

Reducing the risk - Volcanoes

A

Monitoring - remote sensing (detect heat), gas (instruments detect gas), hydrology (measurement of gases dissolved in water)

Prediction - scientific monitoring

Protection - use earth embankments, use explosives to divert lava

Planning - use hazard maps to show the likely areas to be affected so people can be evacuated