Geography - Natural Hazards

Natural hazard

A natural threat to people or property

Natural disaster

Natural hazard that has happened

Geological hazard

A hazard caused by land and tectonic process

E.g volcanoes, earthquakes, landslidea and avalanches

Meteological hazard

A hazard caused by weather and climate

E.g tropical storms and extreme weather

Factors that affect hazard

Vulnerability, capacity to cope, nature of natural hazards ( type of hazard, frequency and magnitude)

Primary effects

Buildings destroyed, people injured and killed, crops and water supplies contaminated

Secondary effects

Emergancy vehicles can’t get through, spread of disease, food shortages, weakened economy

Immediate response

Evacuation, rescue, provide food/drink/shelter, foreign aid

Long - term responses

Repair homes, improve monitoring and evacuations, economic recovery (e.g promote tourism)

Continental plate

30 - 50 km thick

Less dense

Oceanic plate

5 - 10 km dense

More dense

Destructive plate margin (collision)

2 continental plates move towards each other, creating fold mountains (e.g Indian plate and Asian plate)

Destructive plate margin (subduction)

One continental plate and one oceanic plate move towards each other, leaving the oceanic plate to subduction and sink under the continental plate (e.g South American plate and the Pacific plate)

Constructive plate margin

Two plates move away from each other (e.g Eurasian plate and the North American plate)

Conservative plate margin

Two plates move next to each other, either in the same direction at different speeds or in opposite directions (e.g North American plate and the Pacific Ocean plate, creating the San Andreas Fault)

Volcanoes

Form at destructive subduction and constructive plate margins

Oceanic plate melts and rises through the cracks

Magma rises up into the gaps and erupts

Earthquakes

All types of plate margins

Friction buods up than when rock cracks, the energy is released

Focus is where the earthquakes starts (under the ground)

Epicentre is the point on the surface of the earth directly above the focus

Monitoring earthquakes

Seismometers and lasers

Monitoring volcanoes

Monitor the escaping gas and change in shape

Predicting earthquakes

Cannot be predicted fully but a location can be forcast

Predicting volcanoes

Close monitoring

Planning for earthquakes and volcanoes

Avoid high risk areas

Educate people

Plan evacuation routes

Stockpile emergency supplies

Protection for earthquakes

Buildings built with reinforced concrete

Buildings strengthened with steel frames

Automatic shut off valves for gas and electricity

Protection for volcanoes

Strengthened so they do not collapse under the weight of ash

Tropical storms

5° - 30° North and South of the equator

Water is over 27°c

Difference in wind speed is high

Eye of the tropical storm

Low pressure, light winds, no rain, no clouds

Eye wall of a tropical storm

Strong winds, storm clouds, heavy rain

Affect of climate change on tropical storms - frequency

Oceans stay 27°c for longer leading to more opportunities for storms

Affect of climate change on tropical storms - Intensity

More evaporation for more powerful storms

Affect of climate change on tropical storms - Distribution

More area of warmer oceans - more area for tropical storms

Monitoring for tropical storms

Radar to track and monitors it

Prediction of tropical storms

Prediction of where and when a storm will hit

Planning of Tropical storms

Avoid high risk areas

Plan evacuation routes

Protection from Tropical storms

Houses and buildings designed to withstand tropical storms

Flood defences

Uk weather hazards

Strong winds, heavy rainfall, snow and ice, droughts, thunderstorms, heat waves

Climate change

Warming of the earth

How to tell climate change

Ice and sediment cores

Pollen analysis

Tree rings

Natural causes of climate change

Orbital changes (more solar radiation)

Volcanic activity (debris from the eruption can reflect light)

Solar output (reduced solar output cools the earth)

Human causes of climate change

Burning fossil fuels add to the greenhouse effect

Farming (livestock/rice) release methane

Deforestation stops plants absorbing carbon dioxide

Environmental affects of climate change

Sea levels rise

Ice caps melt

More flooding

Bleaching of coral reefs

Decreased biodiversity

Impact on people from climate change

Death due to heat

Too warm to live in some areas

Costal areas lost to the water rising

Changes to farming as some methods become unavailable

Mitigation of climate change

Planting trees

Carbon capture

Clean energy production

International agreements

Adaptation of climate change

Changes to farming

Managing water supplies

Better flood warning systems