AQA GCSE Geography Hazards
Key Idea
Content
Natural hazards pose
major risks to people
and property
Definition of a natural hazard.
Types of natural hazard
Factors affecting hazard risk
Plate tectonics theory.
Global distribution of earthquakes and volcanic eruptions and
their relationship to plate margins.
Physical processes taking place at different types of plate
margin (constructive, destructive and conservative) that lead to
earthquakes and volcanic activity.
Earthquakes and
volcanic eruptions are
the result of physical
processes.
The effects of, and
responses to, a
tectonic hazard vary
between areas of
contrasting levels of
wealth.
Primary and secondary effects of a tectonic hazard.
Immediate and long-term responses to a tectonic hazard.
Use named examples to show how the effects and responses to
a tectonic hazard vary between two areas of contrasting levels
of wealth.
Management can
reduce the effects of a
tectonic hazard.
Reasons why people continue to live in areas at risk from a
tectonic hazard.
How monitoring, prediction, protection and planning can reduce
the risks from a tectonic hazard.
Global atmospheric
circulation determine
patterns of weather
and climate.
General atmospheric circulation model: pressure belts and
surface winds.
Tropical storms
(hurricanes, cyclones,
typhoons) develop as
a result of particular
physical conditions.
Tropical storms have
significant effects on
people and the
environment.
The UK is affected by a
number of weather
hazards.
Extreme weather
events in the UK have
impacts on human
activity.
Climate change is the
result of natural and
human factors, and
has a range of effects.
Managing climate
change involves both
mitigation (reducing
causes) and
adaptation
(responding to
change)
Tropical storms (hurricanes, cyclones, typhoons) develop as a
result of particular physical conditions.
An understanding of the relationship between tropical storms
and general atmospheric circulation.
Causes of tropical storms and the sequence of their formation
and development.
The structure and features of a tropical storm.
How climate change might affect the distribution, frequency
and intensity of tropical storms.
Primary and secondary effects of tropical storms
Immediate and long-term responses to tropical storms.
Use a named example of a tropical storm to show its effects and
responses.
How monitoring, prediction, protection and planning can reduce
the effects of tropical storms.
An overview of types of weather hazard experienced in the UK
An example of a recent extreme weather event in the UK to
illustrate:
• causes
• social, economic and environmental impacts
• how management strategies can reduce risk
Evidence that weather is becoming more extreme in the UK
Evidence for climate change from the beginning of the
Quaternary period to the present day.
Possible causes of climate change:
• natural factors – orbital changes, volcanic activity and solar
output
• human factors – use of fossil fuels, agriculture and
deforestation.
Overview of the effects of climate change on people and the
environment.
mitigation – alternative energy production, carbon capture,
planting trees, international agreements
adaptation – change in agricultural systems, managing water
supply, reducing risk from rising sea levels.
R - Nope
A – A bit
G - Yep
Revised
Key idea: Natural hazards pose major risks to people and property
Definition of a natural hazard: A Natural Hazard is any natural event that has the potential to endanger
human life, the economy and property.
Types of natural hazard:
 Tectonic – such as earthquakes or tsunamis, which involve movement of tectonic plates in the earth’s
crust.
 Atmospheric – Created in the atmosphere, by the movement of air and water, such as hurricanes
 Geomorphological –such as flooding, which occur on the earth’s surface.
 Biological – Any biological substance that poses a threat to the health of people, such as forest fires,
which involve living organisms.
Factors affecting hazard risk:
Globally, the incidences of natural hazards is increasing. As a result of human influences such as global
warming, deforestation and urbanisation, the frequency and magnitude of natural hazards are increasing.
With 8 billion people expected to populate the planet by 2024, it is inevitable that the risk will increase as
there are even more people to interact with natural events. However, the risk of natural hazards is also
made worse by the locations in which people live, whether out of choice or necessity.
Key Idea: Earthquakes and volcanic eruptions are the result of physical processes.
Plate tectonics theory:
Global distribution of earthquakes and volcanic eruptions and their relationship to plate margins:
Physical processes taking place at different types of plate margin (constructive, destructive and
conservative) that lead to earthquakes and volcanic activity:
Destructive Plate Margin
1. When oceanic and continental crust meet, the
oceanic crust subducts or is pulled down by gravity
into the mantle below the lighter continental crust
because it is more dense
2. As the oceanic plate is subducted, pressure builds up
and can trigger violent earthquakes.
3. As the oceanic crust subducts, it takes sea water with
it which makes it less dense than the mantle. At the
same time, the heat produced by friction turns the
sinking plate into liquid rock
4. The hot magma tries to reach the surface, where it
succeeds there will be violent volcanic eruptions.
5. As the oceanic plate moves towards the continental
plate, the land on the edge of the continental plate
gets crumpled up to form fold mountains like the
Andes in South America. The subduction of the
plates also causes deep ocean trenches.
Constructive Margin
1. This is where ridge push is causing the two plates to
move apart.
2. As the plates move apart a gap (ridge) appears and is
filled by lava which cools and forms new crust.
3. The ridge is characterised by a line of volcanoes.
Earthquakes and volcanic eruptions do occur at
these margins but they are usually gentle in
comparison to those at other plate margins.
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Conservative Margin
1. This is where two plates moving in the same
direction slide past each other. One plate moves
faster than the other.
2. Pressure builds up because the plates do not move
smoothly. When the pressure is suddenly released,
severe earthquakes occur.
3. No plates are being created or destroyed at this
margin so it is called a called a ‘conservative
margin’. In some places, the margin is easily visible
on the surface of the earth.
One reasons plates move is due to slab pull and another reason is due to ridge push
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Key Idea: The effects of, and responses to, a tectonic hazard vary between areas of contrasting levels of
wealth.
Earthquakes:
Primary Effects
 Buildings and bridges collapse
and homes destroyed.
 People are injured or killed by
collapsed buildings and falling
debris.
 Roads, railways, ports and
airports are damaged.
 Electricity cables, gas and water
pipes and communication
network are damaged, cutting
off supplies.
Secondary Effects
 EQs can trigger landslides and tsunamis – these destroy more
buildings causing more injuries and deaths.
 Leaking gas can be ignited, starting fires.
 People are left homeless and could die e.g. from the cold.
 There’s a shortage of clean water and lack of proper sanitation
– easier for disease to spread.
 Due to blocked roads, air and emergency vehicles can’t get
through and trade is difficult.
 Businesses are damaged or destroyed – lost income and
tourism.
 Repairs and reconstruction can be very expensive, so weakens
economy.
Volcanoes:
Primary Effects
 Buildings and bridges are destroyed by lava
flows and pyroclastic flows. Buildings may
collapse due to the weight of the ash.
 People and animals are injured by pyroclastic
flows, falling rocks and lava flows.
 Crops are damaged and water can be
contaminated.
 People, animals and plants suffocate by
volcanic gases.
Secondary Effects
 Mudflows (lahars) forms when volcanic
material mixes with water.
 Flooding can be caused by snowmelt.
 Rocks and ask can clog up rivers.
 Transport networks are blocked.
 People are left homeless. Damage to
businesses can cause unemployment.
 Tourism can be disrupted.
 Ash makes fields more fertile.
 Recovering after the eruption can take a very
long time, weakening the economy.
HIC - Earthquake Example: L’Aquila, Italy (2009)
Location and 
Date
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Cause
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Effects
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Secondary
Effects
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Immediate
Responses
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Long Term
Responses
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6th April 2009
The Abruzzo region of Italy, North East of Rome
6.3 on the Richter scale
Movement along a crack in the plate at a destructive margin-Europe and African
plates
308 deaths
1500 people were injured
Between 10 and 15 000 buildings were destroyed
67,500 people were made homeless.
Most of l'Aquila's medieval buildings suffered damage.
San Salvatore Hospital was so badly damaged that patients had to be evacuated.
The Hospital's new wing, opened in 2000, was thought to be EQ proof but suffered
extensive damage and had to be closed.
Much of L’Aquila University accommodation was damaged including a student
dormitory.
The number of students able to study at L’Aquila university had fallen
Burst water mains in the town of Pagliano caused a landslide and mudflow.
A housing shortage caused the price of housing and rented accommodation
increased rapidly
Aftershocks caused landslides and rockfalls which damaged housing and blocked
transport routes
Clean water, hot food, tents and blankets were distributed.
40,000 tents were given out to residents who could not have hotel accommodation.
12 000 rescue workers were sent to the area.
The Red Cross donated $171,000
The EU donated $553 million.
The cost of mortgages, gas and electricity were suspended.
The Post Office offered free mobile phone calls.
L’Aquila was declared a state of emergency, which speeded up donations from the
EU and USA.
It was estimated that it would take 15 years to rebuild.
Residents did not have to pay any tax in 2010.
Students were given free pupil transport.
LIC - Earthquake Example: Gorkha, Nepal (2015)
Location and
Date
Cause
Primary
Effects
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Immediate
Responses
Long Term
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Epicentre was Barpak, 80 kilometres northwest of the city, Kathmandu.
25th April 2015, 12.58 am.
7.8 Richter scale
The India plate is moving north at around 45mm a year and pushing under the Eurasian
plate.
A total of 8841 people died, 16,800 were injured and 1 million were made homeless.
50 percent of the schools were destroyed
352 aftershocks, including a second earthquake on 12th May 2015 measuring 7.3
magnitude.
Food, water and electricity were reduced.
Many modern buildings collapsed as there were no compulsory building standards in
Nepal.
Many people had to live in temporary shelters as their homes collapsed due to the 352
aftershocks.
The earthquake triggered an avalanche on Mount Everest, it swept through Everest
Base Camp and killed 19 people.
Historic buildings and temples in Kathmandu including the iconic Dharahara Tower a
UNESCO World heritage Site were destroyed.
Rice seed stored in homes was ruined in the rubble, this caused food shortages and
income loss as they weren’t able to plant the rice.
The UK gave $126 million to provide emergency aid and start rebuilding areas.
The Red Cross provided tents for 225,000 people.
The UN and WHO distributed medical supplies.
Sherpas were used to deliver emergency supplies to remote areas.
FB launched a safety feature.
The Durbar Square was opened in June 2015 and Mount Everest in August 2015.
Recovery phase started 6 months after the earthquake to expand crop production and
train people to repair irrigation damaged by mudslides.
Key Idea: Management can reduce the effects of a tectonic hazard.
Reasons why people live near volcanoes:
 Geothermal energy: Many countries generate electricity from heat from magma
 Tourism: Volcanoes bring millions of people to them each year
 Rich Soil Volcanic soil is the most fertile in the world, meaning high yield and high profit
 Risk: Some volcanoes have laid dormant for years and people feel they do not pose a risk.
Reasons why people live in earthquake prone zones:
 Risk: Many EQ zones are near the sea/coast. People perceive the benefit of living in these areas
outweighs the risk.
 Earthquake Proof Buildings – As buildings have been developed to withstand an earthquake homes
and businesses can be built in earthquake zones with less risk.
 Water – Fault lines associated with earthquakes allow water to more easily reach the surface. This is
particularly important in regions
Monitoring
Using scientific equipment to detect warning signs of events such as a volcanic eruption.
Prediction
Using historical evidence and scientific monitoring to judge when and where a tectonic hazard
may occur. Using knowledge of plate margins to identify where earthquakes are most likely.
Protection
Designing buildings that should withstand tectonic hazards or evacuating people away from
the dangers posed by volcanic eruptions.
Planning
Identifying and avoiding building on places that are most at risk. Developing methods that
reduce the impacts of an eruption or earthquake before a hazard occurs.
Monitoring:
1. Networks of seismometers and lasers monitor earth movements.
2. Scientists can monitor small earthquakes, increased gas emissions, changing shape of the volcano.
Prediction:
1. Earthquakes cannot be reliably predicted, but by monitoring the movement of tectonic plates,
scientists can forecast which areas should prepare.
2. Volcanoes can be predicted. This gives people time to escape and reduces deaths/injuries.
Protection:
1. Buildings can be designed to withstand earthquakes – reinforced concrete, deep foundations which
absorbs energy.
2. Existing buildings can be strengthened so are less likely to collapse.
3. Automatic gas shut off switches to prevent fires.
Planning:
1. Future development can avoid high risk areas.
2. Emergency services can plan and train for disasters and people can be educated so they know what
to do.
3. Governments can plan evacuation routes.
4. Emergency supplies like blankets, clean water and food and be stockpiled.
Key idea: Tropical storms (hurricanes, cyclones, typhoons) develop as a result of particular physical
conditions.
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Tropical storms are usually found in areas of low latitude,
between 5 and 30 degrees because the sea temperatures
must be above 27⁰C
Formation of Tropical Storm
1. The ocean has to reach 27⁰C.
2. Warm air from the ocean quickly rises.
3. Latent heat is releases during condensation fuelling the storm.
4. A wall of cumulonimbus clouds form and it rains heavy.
5. The cold air sinks, creating a calm eye.
6. Low pressure is created above the ocean and winds at the
Earth’s equator cause more warm air to be sucked in and the
storm to spin.
7. When the wind speed reaches up to 75mph it is called a tropical
storm.
Hurricanes are measured using the Saffir-Simpson Hurricane Wind Scale. Is categorises the hurricane from
1-5 based on sustained wind speed. It estimates potential property damage.
The Impact of Climate change
Frequency - How often tropical storms occur.
Intensity - How is the intense or powerful are the tropical storms.
 Warmer temperatures in the atmosphere are causing a rise in sea surface temperatures which means
tropical storms are more likely because a temperature of 27 degrees occurs more often.
 The source areas of tropical storms may extend further north and south of the equator
 More people living in coastal communities in the future means that more people will be affected.
Tropical Storm Responses
Immediate responses occur straight away, as a disaster happens an in the immediate aftermath.
Long-term responses are responses that occur in the weeks, months and years after an event
Management:
 Aircraft now fly through tropical storms at 10 000 feet. Sensors called dropsondes are released which
collect air pressure, wind speed and rainfall data every second and transmit the data to the aircraft.
 NASA monitors weather patterns across the Atlantic using two unmanned aircraft called Global Hawk
drones.
 The National Hurricane Centre in Florida predicts the path of a tropical storm and its intensity for up to
seven days using a ‘track cone’.
 Disaster supply kits, ensure vehicles are fully fuelled, knowing where official evacuation centres are,
storing loose objects and planning with your family about what to do.
 Federal Emergency Management Agency (FEMA), they advise homeowners the following;
 Install storm shutters on windows, install an emergency generator, tie down garden objects that could
become windborne such as garden furniture, reinforce garage doors, remove trees close to buildings.
 Planning and community awareness must be raised so that people understand and can respond to the
dangers.
Case Study: Cyclone Nargis(Myanmar 2008)
Location and
Date
Primary
Effects
Mynamar, Asia
27th April 2008
 135mph winds
 Strom surge of 7.6m
 Heavy rain
 Farmland, livestock and fisheries destroyed.
 Rice fields flooded
 138,000 deaths
Secondary
 Lack of food and water disease spread
Effects
 Children orphaned
 75% buildings collapsed
 $10 billion worth of damage
 1,163 temples destroyed
 1 million people homeless
Immediate
 Emergency relief supplies including food, tents, blankets, water purifiers and medical
Management
equipment
 Most aid was from international organisations rather than the military government.
 5 regions were classes as disaster areas
 6th May, the government as for UN help
Long term
 UNICEF supported the needs of nearly 300 000 women and children.
management.  90% of children have been vaccinated against measles.
 UNICEF provided 250 000 people with 3 litres of safe drinking water per day.
 246 new wells have been dug.
 Planting Mangroves that can provide protection from high winds.
 The UN along with the Italian Government are supporting small scale fisheries to
support local communities to develop sustainable incomes and jobs.
Key Idea: Global atmospheric circulation helps to determine patterns of weather and climate.
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Global Atmospheric Circulation is created because
of the differing insolation received by different
latitudes across the globe.
The pattern of heating causes air to rise and fall
(high and low pressure).
This then causes cells called convection cells which
cause winds to flow eastwards around the planet.
This therefore directly influences the distribution of
climate zones globally.
The Coriolis effect bends and spins the warm rising air.
Hurricanes in the northern hemisphere bend to the
ring, which causes the clouds to swirl anticlockwise,
whereas cyclones in the southern hemisphere swirl in a
clockwise direction
Key idea: The UK is affected by a number of weather hazards
Extreme weather is when a weather event is significantly different from the average or usual weather
pattern, and is especially severe or unseasonal.This may take place over one day or a period of time. A
flash flood or heat wave are two examples of extreme weather in the UK.
Examples of extreme weather events in the UK:
• Drought - caused by a lack of rain.
• Flash floods - caused by too much rain in a short period of time.
• Strong winds and storms.
• An extreme cold spell.
• An extreme heat wave.
Boscastle Flood:
Date
Monday 16th August 2004
Physic  200mm fell over Ottersham Moor, to the east of Boscastle, within a 4 hour period. This was
al
combined with coastal winds and a rising tide. The ground was also already saturated from
Causes
previous rainfall events.
 River Jordan and Valency meet.
 Low drainage density and small drainage basin
Human  Building on flood plains
Causes  Bridges
 Clearing vegetation from the valley
Effects  The floods came so quickly, businesses could not prepare. This meant losses on damaged or
destroyed stock were substantial
 The tourist industry was affected – it took months to repair the damage and tourist number
fell as they avoided the area.
 84 cars were carried out to sea by the 3m high wall of water that swept through the village.
Roads were damaged and two months later there was still no public car parking area in the
village.
 54 properties suffered varying degrees of damage. Structural engineers estimated the cost
of repair could reach £500 million.
 The harbour area was severely damaged and residents could not return home for more
than 10 days. They then had to wear protective clothing in case of contamination from
broken sewers.
Manag  Increase Capacity: widen channel and deepen channel
e-ment  Increased Velocity: concrete channel and straighten channel
 Reduce Discharge: build dams and plant vegetation
Evidence of more extreme weather
 Increased droughts in the UK
 Increase flooding.
 Increased flash floods.
 Stronger wind storms
 Periods of heavy snow
 Periods of exceptionally high temperatures
Key idea: Climate Change
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Climate change – the large-scale, long-term shift in the planet's weather patterns or average
temperatures. Earth has had tropical climates and ice ages many times in its 4.5 billion years.
Global warming - A gradual increase in the overall temperature of the earth’s atmosphere generally
attributed to the greenhouse effect caused by increased levels of carbon dioxide, CFCs, and other
pollutants.
Quaternary period – the current geological period dating from 2.6million years ago to the present day.
We live in the Holocene epoch of the Quaternary period, which covers the last 12,000 years since the
end of the last ice age.
Cause of Climate Change
Natural Factors:
 Some scientist believe climate change is due to natural events.
 The way the sun moves round the Sun changes.
 Volcanic ash can block out the Sun, reducing temperatures on the Earth.
Human Factors:
 Burning fossil fuels where CO2 is released.
 Farming of livestock and growing rice produces a lot of methane.
 Cemenet production released a lot of CO2.
 Deforestation where less trees can remove CO2 and CO2 is also released when trees are burnt.
Impact of Climate Change
 Agriculture
 Forests
 Health
 Wildlife
 Extreme weather
 Tourism
 Sea level rise
 Flooding
 Fishing industry
Managing Climate Change
Mitigation – action taken to reduce or eliminate the long term risk to human life and property
making international agreements about carbon reduction targets.
Adaptation – actions taken to adjust to events such as climate change
• to reduce potential damage and limit the impacts,
• to cope with the consequences.