Earthquakes Volcanoes

Con

stru

ctive

Plate

Marg

in

1. As the plates move apart, a gap appears between the two plates

2. This gap allows magma to rise up from the mantle.

3. This movement of magma creates small earthquakes.

1. As the plate move apart, a gap appears between the two plates

2. This gap allows magma to rise up from the mantle creating new land and volcanoes.

3. Over time, this allows the sea floor to spread.

Dest

ruct

ive P

late

Marg

in

1. Oceanic and continental plate collide2. Oceanic plate subducts because it

heavier.3. As the plate subducts it sticks with

the continental plates increasing pressure

4. When the pressure reaches a critical level, it is released in the form of seismic waves forming a violent earthquake

1. Oceanic and continental plate collide2. Oceanic plate subducts because it heavier.3. As the plate subduct, friction heats up the

oceanic plate forming magma. 4. The magma rises to the surface as it is

less dense than the surround rock.5. This forms a volcano.

Con

serv

ative

Plate

Marg

in

1. As the plates move side by side they stick.

2. This increases the pressure.3. When the pressure reaches a critical

level, it is released in the form of seismic waves forming a violent earthquake.

Volcanoes are not found at conservative plate boundaries.

Earthquakes are commonly found in thin narrow belts associated with a plate boundary.

Most volcanoes are distributed along the plate boundary.

An example of a highly active earthquake zone is the west coast of North America and South America

Occasionally, volcanoes are found in the middle of plates (e.g. Hawaii). These are called hot spots.

Global Distribution of Earthquakes and Volcanoes

How are earthquakes and volcanoes formed at different plate boundaries?

Constructive Plate (move apart) Destructive Plate (collide) Conservative Plate (side by side)

Primary Effects Secondary Effects

1. 316,000 died to the crushing injuries of collapsed buildings

2. Electricity was cut off3. Over 50 hospitals and 1000 schools were

destroyed4. Main prison was destroyed. 4000 inmates

escaped in total.5. Over 300,000 people were injured.6. Telecommunication networks were

severely damaged.

1. Increase in crime. Looting began.2. Estimate cost of repair was $14 billion3. 1 in 5 people lost their job4. Haiti’s largest industry in clothing had to

close5. Cholera spread due to the poor sanitation6. People starved because food access was

limited7. 1.3million people were left homeless

MEDCs LEDCs

Number ofdeaths –tends to be a low number

• Faster and efficient emergency response

• People are better prepared e.g. EQ drills and EQ kits

• Well built houses

Number of deaths:tends to be a high number

• Houses collapse causing more death

• More diseases (e.g. cholera) due to lack of clean water due to broken water pipes

Buildings destroyed – tends to be a low number

• Buildings are constructed usingflexible materials and other EQ proof strategies (e.g. Kobe, Japan).

Buildings destroyed: tends to bea high number

• Higher proportion of shanty towns which aren’t EQ proof.More people are made homeless (e.g. Haiti).

Economic damage –tends to be higher

• Buildings are more expensive to repair

• Insurance payouts are higher• Businesses can close if transport

links are affected by EQ.

Economic damage –tends to be not as expensive

• Insurance payouts are less and buildings are not as expensive to repair.

Date 4.53pm on Tuesday 12 January 2010

Location 16miles west of Port-au-Prince, Haiti’s capital

Magnitude (strength) 7.0 Richter scale

Cause Conservative boundary between Caribbean plate and North American Plate

Deaths 316,000 deaths

Aftershocks 52 aftershocks greater than 4.5 on the Richter scale felt during the two weeks after the earthquake

Buildings destroyed 250,000 homes and 30,000 commercial buildings were destroyed.

Number of people affected

3 million people affected

What were the effects of the Haiti Earthquake?Key Facts:

Primary effects are a direct result of the hazard. They occur immediately.

Secondary effects are an indirect result of the hazard, but may take time to occur.

What were the primary and secondary effects of the Haiti Earthquake?

Why do the effects of earthquakes vary between MEDCs and LEDCs?

What strategies can be used to reduce the damaging effects of earthquakes?

MEDCs LEDCs

Predic

tion

1. Seismic Gaps – use computers and GIS to map previous earthquakes. Any gaps in earthquakes along a fault line could be an indication than an earthquake is likely.

2. Seismometers – a delicate instrument that can detect foreshocks (small earthquakes) which are a potential precursor to a larger earthquake occurring.

Predicting EQs is difficult – non of the above methods are relatively successful. They can’t predict when an EQ will occur.

1. LEDCs lack the technology to predict EQs. Often have to work with MEDCs for

help.

Plan

ning

1. Building design – using expensive technology to reduce the damage.

1. Rubber shock absorbers in the foundations to absorb the seismic waves (e.g. Kobe, Japan).

2. Computer controlled movable counter weights in the roofs of buildings counter the seismic waves

3. Automatic sprinkler systems and gas shut off valves prevent fires from spreading

1. Building design - using affordable technology to keep people in LEDCs safe:

1. Construct houses out of bamboo –light, flexible structure (e.g. all Bamboo houses in Costa Rica survived an EQ in Jan 2009)

2. Hollow concrete bricks cause less damage if they fall

3. Small windows in houses – fewer weak spots for the EQ to exploit

4. Lightweight roof tops. In Haiti, the rooftops were too heavy.

Prepa

rati

on

• Residents to prepare an EQ kit which includes vital essentials (e.g. food, water and medicine)

• Education – In Japan, Disaster Prevention Day held every year on the 1st of September reminds students what to do in the event of an EQ via EQ drills.

• Earthquake shaking maps – people are made aware of what to do where they live. The maps also help authorities design building codes

• Food, water and medicine is organised in advance. International Charities stockpile resources so that they are able to respond quickly to an EQ (e.g. Nepal, 2015)

• Survival Skills and evacuation procedures are taught to local people by international organisations and charities (e.g. USGS teaches villagers in the Philippines how to prepare for an EQ.)

Why do people live in earthquake zones?

Insurance - Many people in MEDCs can afford to live in earthquake zones because they’ve got the funding an

back up to provide incase of an earthquake event e.g.

insurance money.

Inability to relocate – Many in LEDCs may be restricted to earthquake zones as they can’t afford to relocate to a safe location (Pakistan, Iran

& Indonesia)

Building Space – In Japan, there is very little flat land available to build on. People are forced to locate on flat areas which are susceptible

to Earthquakes.

Major cities already located in Earthquake zones

- many cities were built before scientists understood the causes Earthquakes e.g.

San Francisco

Protection – Can afford to live in these areas as

buildings are earthquake proof and emergency

services are well trained (Japan).

What were the effects of the Montserrat Eruption?

Date July 1995-1997

Location Montserrat, South East Caribbean.

Cause Subduction of Atlantic Plate under the Caribbean plate (Destructive)

Volcanoes Chances Peak, Soufriere Hills

Deaths 19

Destroyed Capital city – Plymouth, airport & port

Coverage ¾ of the island. (Total area 100sq miles)

Number of people affected

7000

Key Facts:

Primary effects are a direct result of the hazard. They occur immediately.

Secondary effects are an indirect result of the hazard, but may take time to occur.

What were the primary and secondary effects of the Montserrat Eruption?

Primary Effects Secondary Effects

1. Pyroclastic flow destroyed the capital of Plymouth

2. Airport runway covered in ash and terminal building collapsed.

3. Seven hospitals destroyed4. Roads, bridges and infrastructure destroyed5. Agricultural fields covered in ash. 6. Radio transmitter destroyed.

1. Coral reef severely damaged – endangered species now at high risk of extinction

2. Some residents have suffered from lung diseases caused by ash inhalation

3. Unemployment increased as a result of the collapse of the tourist industry, farmland and business.

4. The nearby island of Antigua became overpopulation due to people migrating from Montserrat.

5. 7000 people made homeless who left Plymouth to the north of the island

Why do the effects of volcanic eruptions vary between MEDCs and LEDCs?

MEDCs LEDCs

Number ofdeaths –tends to be a low number

• Better prediction methods –people are warned and evacuated

• Better telecommunications to warn people

• People are evacuated effectively away from the danger zone.

Number of deaths:tends to be a high number

• People aren’t efficiently warned that a volcanic eruption is imminent.

• More diseases (e.g. cholera) due to lack of clean drinking water due to broken pipes.

Buildings destroyed – tends to be a low number

• Towns and villages are better planned – built in areas not at risk from lava or pyroclastic flows.

Buildings destroyed: tends to bea high number

• Houses collapse as they are not strong enough to hold the weight of an ash fall.

Economic damage –tends to be expensive

• Buildings are more expensive to repair

• Insurance payouts are higher• Businesses can close if transport

links are affected by volcanic eruption.

Economic damage –tends to be not as expensive

• Insurance payouts are less and buildings are not as expensive to repair.

What strategies can be used to reduce the damaging effects of volcanic eruptions?

MEDCs LEDCs

Predic

tion

• Use sophisticated technology such as seismometers to detect small earthquakes

and tiltmeters which detect ground swelling. Both are due to rising magma.

• Can predict volcanic eruptions through observation – e.g. swelling of the ground surface and increase in gas emissions.

• Technology from MEDCs can help predict volcanic eruptions e.g. British Geological Survey (BGS) provided seismometers to

help predict the Montserrat eruption

Plan

ning

• Hazard mapping zones – areas at risk of volcanic hazards are identified and

available on the internet. This is also helpful in planning potential evacuation

routes (e.g. Hawaii, USA)• Restricting access to an area – e.g. the

area near Mt St Helens before 1980 eruption.

• Evacuation of people prior the eruption (e.g. Mt Etna, Italy)

• Evacuation of people prior the eruption (e.g. in Montserrat people were evacuated from the capital Plymouth to the north of

the island). • Restricting access to an area – e.g. the

area near Soufriere Hills, Montserrat was restricted.

Prepa

rati

on

• Build houses with sloping roof tops which are reinforced with steel and made of

smooth materials (e.g. metal) to prevent roof collapsing due to ash.

• Install filter systems in buildings to prevent damage to electrical and computer

systems from ash.• Increase awareness through education.• Divert lava flows away from towns and

villages using earth and rock walls (e.g. Mt Etna, Italy)

• Evacuation of people prior the eruption (e.g. in Montserrat people were evacuated from the capital Plymouth to the north of

the island). • Restricting access to an area – e.g. the

area near Soufriere Hills, Montserrat was restricted.

• Non-government organisations such as USGS can help educate people about what to do during an volcanic (e.g. Mt Pinatubo,

Philippines)• Stockpiling resources e.g. food, water and

medicine and setting up refugee camps (e.g. Mt Pinatubo, Philippines)

Why do people live near volcanoes?

Farming – Volcanic ash contains minerals which provide fertilisation for soils. This is ideal in LEDCs because it provides a good opportunity to develop an income.

Geothermal energy – water can be pumped underground and naturally heated by magma. This turns into steam, which can drive a turbine to make electricity.

Valuable minerals – Gold, silver, copper and lead can be sourced from the remains of extinct volcanoes.

Gemstones – Slowly cooled magma/lava can allow for gemstones to develop e.g. diamonds. These are hugely valuable.

Tourism – volcanoes, geysers and natural hot springs attract tourists from around to world to sample a once in a lifetime experience. Valuable income for an LEDC

1) Tropical storms are created in warm oceans (26oC) between 5o and 25o northand south of the equator.

2) The high temperature causes the water to evaporate and rise into the atmosphere forming an area of low pressure.

3) As the warm, moist air condenses it forms large cumulonimbus clouds which cumulate to form a large storm system

4) Strong winds are created when air rushes from areas of high pressure (edge of storm) to areas of low pressure (centre of storm) along the oceans surface

5) The Earth’s rotation (or spin) causes the storm to rotate. This is known as the Coriolis Force

6 ) As tropical storms pass over land they lose their source of energy and die out.

Where are tropical storms distributed?

How are tropical storms formed?

Hurricanes are typically found in the Caribbean Sea located south east of the United States e.g. Hurricane Katrina, New Orleans USA

Typhoons are found in the Pacific Ocean usually affecting countries like the Philippines and Japan e.g. Typhoon Haiyan, Philippines)

All tropical storms are located between the tropic of cancer and tropic of Capricorn (between 5o and 25o north and south of the equator)

Cyclones are found in the Indian Ocean usually affecting countries like Indonesia and Bangladesh e.g. Cyclone Nargis, Myanmar.

Primary Effect Secondary Effect

• Communication and electricity networks

were severely disrupted.

• An estimated 80% of Tacloban City was

destroyed, trees knocked over or broken,

and cars piled up

• The evacuation centre in Tacloban was

flooded catching people off guard.

• Hospitals in the city were either shut down

or working at partial capacity.

• Farmers lost their crops due to the flooding

• People were made homeless

• Roads were blocked with from landslides

meaning search & rescue were slow

• Shelters were overcrowded. People lived in

squalor.

• Widespread looting and violence occurred in

Tacloban

• Due to the lack of electricity, planes bringing

aid into the country could only operate during

the daylight

• The Philippines economic growth has slowed

down to 1%

• Water was contaminated leading to outbreaks

of diseases.

• People died due to starvation and lack of food.

• Many farmers have lost their only sources of

income.

The main threats to life from tropical storms are :

• Intense winds of 74 – 200 mph which cause trees to break, bridges to collapse, destroy weakerbuildings and send debris flying through the air which can kill anyone outside.

• A storm surge of higher-than-normal sea due to the intense Low Pressure. This leads to sea waterflooding over low-lying coastal areas

• Intense waves that can shut down offshore oil-rigs, capsize ships and cause destruction to coast andport buildings.

• Very intense rainfall which can swell rivers and lead to ‘fresh water’ flooding inland..

What are the dangers of Tropical Storms?

Case Study: What were the effects of Typhoon Haiyan 2013?

MEDCs LEDCs

Number ofdeaths –tends to be a low number

• Better prediction methods –people are warned and evacuated

• Better telecommunications to warn people

• People are evacuated effectively away from the danger zone.

Number of deaths:tends to be a high number

• People aren’t efficiently warned that a tropical storm is imminent.

• More diseases (e.g. cholera) due to clean drinking water. Often contaminated with sewage.

Buildings destroyed – tends to be a low number

• Houses are more likely to resistthe strong winds and storm surge e.g. roof bracing and stilts.

Buildings destroyed: tends to bea high number

• Houses collapse as they are not strong enough to resist the strong winds or the storm surge.

Economic damage –tends to be higher

• Buildings are more expensive to repair

• Insurance payouts are higher• Businesses can close if transport

links are flooding by storm surge.

Economic damage –tends to be not as expensive

• Insurance payouts are less and buildings are not as expensive to repair.

Why do the effects of tropical storms vary between MEDCs and LEDCs?

MEDCs LEDCs

Predic

tion

–m

onit

orin

gan

d G

IS

• Geographical Information Systems –GIS. Computer software packages are

used to track storm paths to enable warnings to be issued e.g. The National Hurricane Centre (NHC) used GIS to predict the path of Hurricane Katrina

which led to some evacuation.• Satellites – the National Hurricane

Centre can use satellites to monitor areas likely to form tropical storms by

using infra red to detect water temperatures over 26oC

• LEDCs lack prediction technology but they can receive advanced warning from MEDCs e.g. the Philippines were alerted by the Joint Typhoon Warning Centre (JTWC) that Typhoon Haiyan was only

five days away. • LEDCs lack the means to effectively

warn people that a tropical storm is imminent.

Educ

atio

n

• The Federal Emergency Management Agency (FEMA), based in the USA, has a website that produces guidelines on how

to prepare for a tropical storm. This includes how to make hurricane kits and

how to prepare your home. • Hurricane Preparedness Week – May

20th to 30th in 2015 – each day details how to prepare for different hazards

that tropical storms bring.

• Not everyone in LEDCs can read or have access to the internet.

• FEMA and other international organisations work with local villages

(e.g. Philippines) to give the people practical advise on how to prepare for a tropical storms – e.g. safest evacuation

routes, how to protect homes etc.

Oth

er

Prepa

rati

onS

trat

egi

es

• Design of buildings1. Window Shutters – prevent damage due

to broken glass2. Roof strapping – Metal bars are placed

on rooftops to bolt them in position so they aren’t blown away.

• Emergency Services –put on standby when a tropical storm is on the way, plans

are checked and key personnel are brought into place ready.

• Evacuation - Vulnerable areas have emergency plans in place which include

evacuation procedures should the risk be high. People in MEDCs are familiar with

evacuation route due to education• Cyclone Shelters• Hurricane Kits

• Evacuation routes – raised pathways that allow people to evacuate efficiently • Cyclone Shelters – safe place for

evacuated 1. Built on stilts to prevent flooding.2. Reinforced concrete so they stay

strong during a cyclone3. Flat rooftops to prevent the wind

from blowing the roof off.4. Small windows/shutters to prevent

injury• Design of buildings – some houses in Bangladesh are built on stilts to protect

against coastal flooding from tropical storms.

• Sirens and Early Warning Systems – to make people aware of a tropical storm

before it happens.

What strategies can be used to reduce the damaging effects of tropical storms?

Should large areas be evacuated if a tropical storm is predicted?

Yes, people should be evacuated No, people shouldn’t be evacuated

Forecasted speed of the tropical storm may be inaccurate – the tropical storm could be much stronger than predicted (e.g. Hurricane Hanna,

Haiti).

The forecasted track of the tropical storm maynot be accurate so the area might not be

affected. In 2010, forecasts were 346km out on average. Evacuation is unnecessarily expensive if

incorrectly forecast.

People on the coast are endangered to the impacts of storm surges and coastal flooding (e.g. Hurricane

Katrina).

People are aware of the dangers of a tropical storm and are well prepared for the impacts. (e.g.

Hurricane Preparedness Week)

Even the strongest, well built houses can be damaged potentially causing death or injury.

Evacuation – could cause panic and congestion on roads. People would be in danger if the tropical storm whilst people were stuck in a traffic jam.

How have tropical storms changed in the past and how might they change in the future?

People who believe climate

change will increase the number and strength of

tropical storms

1. Global warming will increase sea temperatures. 2. Sea temperatures hit 26oC more often meaning more evaporation allowing tropical

storms to occur more often3. More ocean with a higher temperature means that tropical storms will occur in

places that don’t get them now4. If sea temperatures are higher, the strength of the storm will increase. Category

5 storms will become more frequent causing higher amounts of damage.

People who believe that the number of tropical storms will

decrease and alternative arguments

1. Natural cycles - where the number of tropical storms drops but then later increases, followed by another drop.

2. We are currently in an above average period (around 175 globally per year)3. This means the next cycle tropical storms will experience a decrease in number

and strength4. History has shown that this has happened before (see the above graph)5. Increased amounts of coastal development (housing and businesses) and a growing

population has meant there is a greater potential damage when tropical storms hit. For example, Hurricane Katrina cost over $80 billion in damage because it is situated on the coast in a densely populated area with high valued property.

Between the 1950s and 1970s, the number of tropical storms was high – globally averaging 117 tropical storms per year.

Between the 1970s and 1990s, the number of tropical storms was low – globally averaging 75 tropical storms per year.

Between 1990s and 2000s and , the number of tropical storms was high – globally averaging 175 tropical storms per year.

Over time, the number of tropical storms tend to fluctuate between periods of high activity to periods of low activity. This is called a natural cycle.

Scientists are not sure what will happen to the number of tropical storms in the future. Some scientists have the opinion that number and strength of tropical storms will increase due to climate change. However, other scientists believe that the number of tropical storms will stay the same or actually reduce due to natural cycles.

Perhaps, it is the case the that a combination of both climate change and natural cycles are affecting the number of tropical storms in the future.

What are the arguments for and against the frequency and strength of tropical storms increasing in the future?

Natural (physical) Human

Lightning - Some strikes may cause a fire to start, but most are small and die out. However, with the right conditions, fires started by lightning can spread rapidly.

Farming (slash and burn) - This is a method used by farmers to clear land to grow crops. Sometimes these fires can get out of control and spread.

Volcanic Eruptions - volcanoes emit red hot lava and ash. This can start a wildfire.

Arson -This is the act of deliberately starting fires. In some areas, it can account of up to 30% of wildfires and was the major cause of the Australian wildfire in 2009

Spontaneous Heating - Dry plant matter becomes heated to the point at which it will catch fire without a spark being present.This mostly occurs in warm, humid conditions where cool winds are absent.

Broken Bottles - Glass can act as a magnifying glass. This concentrates the suns rays onto a small area. This can set fire to dry leaves or litter that has been dropped by people.

Accidents - Children playing with matches, campfires that have been put out properly and discarded cigarettes can all cause major wildfires.

Broken Pylons - Strong winds can blow down electricity power lines. This can then ignite dry vegetation causing a wildfire.

How are wildfires created?

What are the climatic features needed for a wildfire?

The climate graph (right) shows that July and Aug are the months at highest risk of wildfires. This is because there is a high temperature (line) at around 35oC and a low rainfall (less than 5mm). The vegetation will be dry increasing the amount of available fuel to burn. In addition, strong winds (60-100km/h) will increase the spread of wildfires.

The maps and data below indicate that area B is more likely to suffer from wildfires. This is because the climate data shows a high temperature in area B meaning the vegetation will be dry. Also the nature of the vegetation (in this case forest) and the land uses (picnic site) in area B create ideal conditions for a wildfire to form. Also the prevailing wind is in the direction of the tourist resort potentially increasing damage caused by a wildfire.

In the exam, you could be given a question asking you to describe some climate data (like the example below) and then explain how it helps cause a wildfire.

Case Study; California Wildfire 2007. To what extent are wildfires a natural hazard?

In most cases, wildfires seem to be a caused by a combination of human and natural factors. This is known as a quasi hazard. An example of this is the California Wildfire in 2007.

What are the effects of a wildfire on people and the environment? E.g. California Wildfire 2007

Effects on People Effects on the environment

1. Tourist income fell as the San Diego zoo and Sea World had to be closed

2. Water supplies were polluted by ash3. People were told to stay indoors and keep

windows and doors closed to keep out smoke & ash

4. 85 were injured with burns or lung problems.

5. Farmers lost their entire crops of avocados, strawberries and salad crops from the heat and ash

6. Levels of stress and depression rose for the survivors who had watched their homes destroyed

7. Property insurance rose afterwards as so many houses had been destroyed

8. 9 people died of breathing in smoke9. Businesses lost weeks of profits as over

half a million people were evacuated

1. Soil erosion increased off the Californian hills as there was no vegetation left to slow down heavy autumn rainfall

2. Natural habitats in the Californian forests were destroyed

3. Smoke drifted reducing light levels reaching the ground

1. Caused by the strong Santa Ana winds blowing over the Sierra Nevada Mountains in California

2. As the air is forced over the mountains, the air molecules compress which makes the air warm and dry. This dries up woodland and grassland in California increasing chance of a wildfire starting due to spontaneous heating.

3. Also, the Santa Ana winds are forced through the canyons of the Sierra Nevada Mountains to around 60mph. This can help wildfires spread over large distances.

4. The California Wildfire in 2007 was caused by the strong Santa Ana winds blowing over an electricity pylon igniting the dry vegetation causing a wildfire.

Other Examples:

An arsonist started one of the Black Saturday wildfires in Victoria, Australia in 2009

The Beaver Creek Fire is a forest fire that began on August 7, 2013 after a lightning strike

The 2010 Russian wildfires were caused by record high temperatures causing spontaneous heating. It is thought that climate change was responsible.

Eva

cuat

ion

MANDATORY EVACUATION; An evacuation order is given out my the local government and enforced by local police. Residents have to leave the area designated at high risk.

GISGIS maps are computer generated maps. These maps plot the areas most at risk from Wildfires. People living in high risk areas can adapt the way they live to minimise the chance of starting a wildfire. They can also inform people on potential evacuation routes.

Educ

atio

n

SMOKEY THE BEARCartoon character (primarily aimed at children) used to advise people on how to build campfires and how to (extinguish) put them out safely. Also people are advised how to burn crop debris, the risk of sparks and the disposal of cigarettes.

FIREWISEUser friendly website advising people how prepare your home accordingly to limit the cause and spread of a wildfire. Here are a few examples:1. Surround the house with paths so the fire can’t get as close2. Remove dead vegetation 30 feet around the house3. Widen access roads (12’ wide by 15’ high)4. Construct buildings using non-combustible materials

Rol

eof

em

erg

enc

y se

rvic

es

AIR DROPSAeroplanes and helicopters (fitted with large buckets filled from the sea or nearby lakes) are used to drop water and fire retardant chemicals from the aircraft onto the wildfire.Areas ahead of the wildfire are also sprayed to stop other areas from catching fire.

BACK FIRESThis is where an area ahead of the wildfire is set alight and a controlled burning of the vegetation takes place (e.g. Chaparral plant, California). This removes the fuel for wildfires in a controlled away to stop the spread of a wildfire.

FIRE LINES/FIRE BREAKS Emergency services dig trenches or clear areas of ground using bulldozers where possible, or otherwise by hand. This removes dry grasses, bushes, leaves and twigs to reduce the amount of potential fuel to be burnt stopping the spread of the wildfire.

What are the strategies and methods used to reduce the damaging effects of wildfire?

How can homes be protected from a wildfire?

Many scientists worry that the number of severe wildfires will increase in the future. This will be the result of global climate factors and a higher population of people living in semi-arid areas.

The bars show the frequency of wildfires in the California. As the temperatures have increased from 1970 to 2005 (black line) – so have the number of wildfires from less than 25 a year in the 1970s to over 100 a year by the 2000s.

In the 35 years between 1970 and 2005 the winter snow has been melting earlier each year. This means there is a longer ‘dry spring and summer’ – so the ground will be drier and more ready to catch fire in the summer if there is something to start a fire.

People are increasingly moving out of cities and living in semi-arid areas within commuting distance of big cities such as Melbourne in Australia or Los Angeles in the USA. Living further out means having larger areas between houses – often filled with dry grasslands and trees which help wildfires spread causing more damage.

As global climate change takes place there are likely to be more droughts and stronger winds in many parts of the world which have unreliable rainfall at the moment. This means that the vegetation will become dry meaning more potential fuel for a wildfire.

Also, higher temperatures will create more storms increasing the risk of lightning. This can create sparks on dry vegetation causing more wildfires.

How will the distribution (spread) and frequency (number) change in the future?

Why should areas prone to wildfires be protected?

The map on the right shows an area that is prone to wildfires. There are many reasons why it should be protected:

~ People – save lives …~ Property – save homes and businesses…~ Environment – tourism, soil, vulnerable species …~ Economic – jobs, ~ Infrastructure – roads, services, buildings…~ Food supply – save crops…