Natural hazards

?

Natural hazards

Natural process which could cause death.

They happen anywhere in world e.g flooding but others happen in specific areas e.g volcanoes.

Types of natural hazards are:

➖Geological, caused by land and tectonic processes e.g volcanoes, earthquakes

➖Meteorological, caused by weather and climate e.g tropical storms

The more people in an area where natural hazards happen, greater they will be affected so hazard risk is higher.

The better a population can deal with a hazard the lower the threat e.g higher income countries as they can afford to build flood defences, evacuate people etc..

The impact of them can be Reduced if you know more about when they will occur.

1 of 12

Tectonic plates

The inner core is solid and outer core liquid made from iron and nickel.

Around core is mantle which is semi-molten rock that moves very slowly.

Outer layer of earth is crust which divided into slabs called tectonic plates (float in mantle)

Plates are 2 types 1) Continential which is thicker and less dense 2) Oceanic which is thinner and more dense

The plates are moving due to convection current in mantle. The places where plates meet are called plate margins.

3 types of plate margin

1)Destructive margin - Where 2 plates are moving towards each other. Oceanic plate meets continental plate,oceanic plate forced down in mantle and destroyed which creates volcanoes.

2)Constuctive margins - Where 2 plates are moving away from each other, magma rises from mantle to fill gap and cools creating new crust

3)Where 2 plates are moving sideways past each other or moving in same direction but different speeds.

2 of 12

Earthquakes

Earthquakes are caused by tension built up at 3 types of plate margin.

Primary effects are: ➖Buildings/bridges collapse ➖Homes destroyed
➖People killed or injured by collapsed buildings ➖Roads/railways damaged ➖Electricity,gas,water,communication networks damaged

Secondary effects: ➖People homeless ➖Shortage of clean water and lack of proper sanitation ➖Landslides/tsunamis ➖Leaking gas ➖Blocked roads so vehicles can’t get through ➖Businesses damaged causing unemployment and lost income ➖Repairs very expensive so weakens economy

Immediate responses: ➖Rescue people trapped ➖Recover dead bodies to prevent disease ➖Set up shelters ➖Provide water,food,electricity,gas

Long term responses: ➖Re-house people who lost homes ➖Repair buildings ➖Reconnect electricity,water, gas ➖

3 of 12

Earthquake case study

Place: Kashmir, Pakistan Date:8th October , 2005. Size: 7.6 magnitude scale

Primary effects: ➖ 80 000 deaths from collapsed building ➖10 000 injured

➖100,000 buildings destroyed ➖3 million homeless

Secondary effects: ➖Landslides buried buildings + people ➖Diarrhoea + other diseases spread due to little clean water ➖Freezing winter conditions

Immediate responses: ➖International aid +equipment ➖Tents, blankets and medical supplies were distributed yet it took months to reach certain areas ➖Resuced by hand

Long-term responses: 40 000 people from one destroyed town have been moved to new settlement ➖Aid given to rebuild schools and government money to rebuild homes ➖But government money used on food ➖After 3 years 1000 people still living In tents➖Some schools not rebuilt 10 years after

4 of 12

Volcanoes

Primary effects: ➖Buildings and roads destroyed by lava flows ➖People + animals injured or killed by lava ➖Crops damaged + water contaminated when ash falls ➖People,animals + plants suffocated by volcanic gases

Secondary effects: ➖Mudlfows form when volcanic material mixes with water, Mudflow can cause more injury ➖Flooding can be caused by hot rock, ash + gas ➖Transport networks are blocked so aid vehicles can’t get through ➖People homeless➖Businesses damaged so unemployment + loss of income ➖Tourism disrupted but after increase as people want to see volcanoes ➖Ash makes fields more fertile once broken down ➖Recovering takes long time + cost money weakening economy

Immediate responses: ➖Evacuate people ➖Provise food,water and shelter ➖Treat people injured ➖Rescue people ➖Provide electricity,gas + communication systems ➖Other countries + charities may send aid workers

Long-term Responses: ➖Repair buildings + resettle affected people ➖Improve monitering + evacuation plans ➖Boost economy economy by attracting tourists

5 of 12

Living with tectonic Hazards

Who do people live near them?

➖They have always lived there- moving means leaving family and friends
➖Employed in area- so if they move, need to find new jobs
➖ They will still get help to rebuild houses etc... after Earthquake/ Volcano
➖They think severe Earthquakes/ Volconoes won’t happen again in area
➖Soil around Volcnaoes is fertile so good to grow crops
➖Volcnaoes are tourist attractions- and people want to work in that industry

If you manage tectonic hazards you can reduce the effect.....

Monitoring—Lasers can monitor earth movements and can give warning before earthquake.
Scientists can monitor tell-tale signs before volcanic eruption like escaping gas

Prediction—Earthquakes not reliably predicted but by monitoring can know which area earthquakes may occur.
Volcanic eruptions can be predicted if well-monitored. Predicting gives people time to evacuate.

Protection— Buildings Designed to stand up against earthquakes. Existing buildings strengthened so less likely to collapse. Automatic shut of switches can be fitted to turn gas off to prevent fires

Planning— Future developments planned to avoid areas most at risk from hazards. Emergency services can train. People be educated so know what to do when hazards occur. Governments can plan evacuation routes

6 of 12

Global Atmospheric circulation

Winds are large scale movements of air caused by difference in air pressure.

Differennce in air pressure are caused by differences in temperature between equator and poles.

Winds move from areas of high pressure to areas of low pressure.

Winds are part of global atmospheric circulation loops.

These loops have warm rising air which creates low pressure belt and cool falling air which creates high pressure belts.

7 of 12

Tropical storms

1) They develop over warm water over 27*c and when wind sheer between higher and lower parts of the atmosphere is low.

2) Warm moist air rises and condensation occurs. Releases huge amounts of energy which makes storms powerful. Rising air creates area of low pressure which increases surface winds.

3)Move towards west as near to equator

4) Earth’s rotation deflects(changes) path of winds which causes storm to spin

5) Storm gets stronger due to energy w]from warm water so wind speed increases. They lose strength when they move over land or cooler water as energy from warm water is cut off.

6)Occur between 5*c and 30*c north and south of equator

8 of 12

Tropical storms effects

Primary effects: ➖Buildings destroyed ➖Rivers + coastal areas flooded ➖People drown or injured ➖Roads/ railways damaged ➖Electricity cables damaged ➖Sewage overflows and contaminates water supplies

Secondary effects: ➖People homeless ➖Shortage off clean water + lack of proper sanitation ➖Roads blocked so aid can’t get through ➖Businesses damaged so unemployment ➖Shortage of food if crops damaged

Immediate responses: ➖Evacuate people ➖Rescue people ➖Set up shelters for people whose homes are flooded ➖Give water,food,electricity,gas and communication systems ➖Recover dead bodies to prevent diseases ➖Other countries may send aid workers + supplies

Long-term Responses: ➖Repair homes or rehouse people ➖Repair damaged buildings ➖Improve flood defence systems ➖Improve forecasting to give more warning ➖Promote economic recovery in area to encourage people to return to area ➖Improve building regulations

9 of 12

Uk weather hazards

Rain: ➖Too much rain in short time causes flooding which damages homes+disrupts transport networks ➖Also forces businesses to close and recovering from flooding may be expensive

Wind: ➖Damages properties + distruption to transport ➖Pulled out trees can cause injury ➖Forests damaged when trees blown over ➖Winds strongest in coastal areas

Snow + ice: ➖Cause injures due to slipping ➖Schools and businesses closed ➖Major disruption to roads

Thunderstorms: ➖Heavy rain,lightening and strong winds occur in thunderstorms ➖Common in summer ➖Lightening can cause death + fires that damage property

Hailstorms: ➖Make driving dangerous and damage property and destroy crops

Drought: ➖It is lack of rain + snow ➖Water supplies can run low and can cause economic impacts such as crop failures

Heat waves: ➖Death from heat exhaustion + breathing difficulties ➖Disruption to transport from roads melting

10 of 12

Extreme uk weather

11 of 12

Climate change

12 of 12

Comments

No comments have yet been made

Similar Geography resources:

See all Geography resources »See all Natural hazards resources »