Download Global Distribution of Earthquakes and Volcanoes How are

Global Distribution of Earthquakes and Volcanoes
Earthquakes are commonly found in thin narrow
belts associated with a plate boundary.
Occasionally, volcanoes are found in
the middle of plates (e.g. Hawaii).
These are called hot spots.
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
How are earthquakes and volcanoes formed at different plate boundaries?
Conservative
Plate Margin
Destructive Plate
Margin
Constructive
Plate Margin
Constructive Plate (move apart)
Destructive Plate (collide)
Conservative Plate (side by side)
Earthquakes
Volcanoes
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.
1. Oceanic and continental plate collide
2. 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 collide
2. 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.
1.
Volcanoes are not found at conservative plate
boundaries.
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.
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.
What were the effects of the Haiti Earthquake?
Key Facts:
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 primary and secondary effects of the Haiti Earthquake?
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.
Primary Effects
1. 316,000 died to the crushing injuries of
collapsed buildings
2. Electricity was cut off
3. Over 50 hospitals and 1000 schools were
destroyed
4. Main prison was destroyed. 4000 inmates
escaped in total.
5. Over 300,000 people were injured.
6. Telecommunication networks were
severely damaged.
Secondary Effects
1.
2.
3.
4.
Increase in crime. Looting began.
Estimate cost of repair was $14 billion
1 in 5 people lost their job
Haiti’s largest industry in clothing had to
close
5. Cholera spread due to the poor sanitation
6. People starved because food access was
limited
7. 1.3million people were left homeless
Why do the effects of earthquakes vary between MEDCs and LEDCs?
MEDCs
Number of
deaths –
tends to
be a low
number
•
Buildings
destroyed
– tends to
be a low
number
Economic
damage –
tends to
be higher
LEDCs
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
•
•
Buildings are constructed using
flexible materials and other EQ
proof strategies (e.g. Kobe,
Japan).
Buildings
destroyed:
tends to be
a high
number
•
Higher proportion of shanty
towns which aren’t EQ proof.
More people are made homeless
(e.g. Haiti).
•
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.
•
•
•
•
•
Houses collapse causing more
death
More diseases (e.g. cholera)
due to lack of clean water due
to broken water pipes
What strategies can be used to reduce the damaging effects
of earthquakes?
Prediction
LEDCs
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.
Planning
MEDCs
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
Preparation
•
•
•
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
1.
LEDCs lack the technology to predict
EQs. Often have to work with MEDCs for
help.
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.
•
•
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)
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).
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.
What were the effects of the Montserrat Eruption?
Key Facts:
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
What were the primary and secondary effects of the Montserrat Eruption?
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.
Primary Effects
1.
2.
3.
4.
5.
6.
Pyroclastic flow destroyed the capital of
Plymouth
Airport runway covered in ash and terminal
building collapsed.
Seven hospitals destroyed
Roads, bridges and infrastructure destroyed
Agricultural fields covered in ash.
Radio transmitter destroyed.
Secondary Effects
1.
2.
3.
4.
5.
Coral reef severely damaged – endangered
species now at high risk of extinction
Some residents have suffered from lung
diseases caused by ash inhalation
Unemployment increased as a result of the
collapse of the tourist industry, farmland and
business.
The nearby island of Antigua became
overpopulation due to people migrating from
Montserrat.
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
Number of
deaths –
tends to
be a low
number
•
Buildings
destroyed
– tends to
be a low
number
Economic
damage –
tends to
be
expensive
LEDCs
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
•
•
Towns and villages are better
planned – built in areas not at
risk from lava or pyroclastic
flows.
Buildings
destroyed:
tends to be
a high
number
•
Houses collapse as they are not
strong enough to hold the
weight of an ash fall.
•
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.
•
•
•
•
•
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.
What strategies can be used to reduce the damaging effects
of volcanic eruptions?
MEDCs
LEDCs
Prediction
• Use sophisticated technology such as
seismometers to detect small earthquakes
and tiltmeters which detect ground
swelling. Both are due to rising magma.
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)
Planning
•
Preparation
•
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)
•
•
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
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.
•
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.
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
Valuable minerals – Gold,
silver, copper and lead can be
sourced from the remains of
extinct volcanoes.
Where are tropical storms distributed?
All tropical storms are located between the
tropic of cancer and tropic of Capricorn
(between 5o and 25o north and south of the
equator)
Typhoons are found in the Pacific Ocean usually
affecting countries like the Philippines and Japan
e.g. Typhoon Haiyan, Philippines)
Hurricanes are typically found in the Caribbean
Sea located south east of the United States e.g.
Hurricane Katrina, New Orleans USA
Cyclones are found in the Indian Ocean usually
affecting countries like Indonesia and
Bangladesh e.g. Cyclone Nargis, Myanmar.
How are tropical storms formed?
1) Tropical storms are created in warm oceans (26oC) between 5o and 25o north
and 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.
What are the dangers of Tropical Storms?
The main threats to life from tropical storms are :
• Intense winds of 74 – 200 mph which cause trees to break, bridges to collapse, destroy weaker
buildings 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 water
flooding over low-lying coastal areas
• Intense waves that can shut down offshore oil-rigs, capsize ships and cause destruction to coast and
port buildings.
• Very intense rainfall which can swell rivers and lead to ‘fresh water’ flooding inland..
Case Study: What were the effects of Typhoon Haiyan 2013?
Primary 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
Secondary Effect
•
•
•
•
•
•
•
•
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.
Why do the effects of tropical storms vary between MEDCs and LEDCs?
MEDCs
Number of
deaths –
tends to
be a low
number
•
Buildings
destroyed
– tends to
be a low
number
Economic
damage –
tends to
be higher
LEDCs
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
•
•
Houses are more likely to resist
the strong winds and storm
surge e.g. roof bracing and stilts.
Buildings
destroyed:
tends to be
a high
number
•
Houses collapse as they are not
strong enough to resist the
strong winds or the storm
surge.
•
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.
•
•
•
•
•
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.
What strategies can be used to reduce the damaging effects of
tropical storms?
Prediction – monitoring
and GIS
MEDCs
•
LEDCs
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.
•
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.
Other Preparation Strategies
Education
•
• Design of buildings
1. Window Shutters – prevent damage due
to broken glass
2. 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
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.
•
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 cyclone
3.
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.
•
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 may
not 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?
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.
Between the 1950s and 1970s, the number of
tropical storms was high – globally averaging 117
tropical storms per year.
Between 1990s and 2000s and , the number of
tropical storms was high – globally averaging 175
tropical storms per year.
Between the 1970s and 1990s, the number of
tropical storms was low – globally averaging 75
tropical storms per year.
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.
What are the arguments for and against the frequency and strength
of tropical storms increasing 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 often
3. More ocean with a higher temperature means that tropical storms will occur in
places that don’t get them now
4. 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 strength
4. 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.
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 climatic features needed for 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.
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.
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.
How are wildfires created?
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.
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.
1.
2.
3.
4.
Caused by the strong Santa Ana winds blowing over the Sierra Nevada Mountains in
California
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.
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.
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.
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 ash
3. 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 smoke
9. 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
Role of emergency services
Education
Evacuation
What are the strategies and methods used to reduce the damaging
effects of wildfire?
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.
GIS
GIS 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.
SMOKEY THE BEAR
Cartoon 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.
FIREWISE
User 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 close
2. Remove dead vegetation 30 feet around the house
3. Widen access roads (12’ wide by 15’ high)
4. Construct buildings using non-combustible materials
AIR DROPS
Aeroplanes 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 FIRES
This 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.
How can homes be protected from a wildfire?
How will the distribution (spread) and frequency (number) change in
the future?
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.
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…