Detailed revision notes for the Hazards Topic of the AQA A-Level Geography Syllabus.
The notes include case studies, necessary information and essay plan arguments.
The format of the notes is as follows;
3.2.5.1 The concept of a hazard in geographical context 3
The concept of a hazard and...
Hazards Notes
3.2.5.1 The concept of a hazard in geographical context 3
The concept of a hazard and its potential impact 3
Risk and vulnerability 3
Hazard perception 4
Hazard response 4
Aspects of hazards and their e ects on human response 4
The Park Model / disaster response curve 5
The hazard management cycle 6
3.1.5.2 Plate Techtonics 7
The structure of the earth 7
Plate tectonic theory 7
Plate Boundaries 8
3.2.5.3 Volcanic Hazards 13
Nature and Distribution 13
Magnitude, frequency, regularity and predictability 14
The impacts of volcanic activity 15
Social, economic, political and environmental e ects 16
Response and risk management to volcanic hazards 16
Case studies 17
3.1.5.4 Seismic Hazards 22
Nature and distribution 22
Magnitude, frequency, regularity and predictability 22
The impacts of seismic hazards 23
Social, economic, political and environmental e ects 25
Response and risk management 26
Case studies 27
3.1.5.5 Storm Hazards 30
The nature of tropical storms and underlying causes 30
Response and risk management 33
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,Case studies 34
3.1.5.6 Fires in Nature 38
Natures of Wild re 38
Risk Management 40
Case studies 41
Multi-Hazardous environment case study 45
Local scale hazardous setting: Kobe, Japan 46
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, 3.2.5.1 The concept of a hazard in geographical context
The concept of a hazard and its potential impact
• A hazard is a potential threat to human life and property cause by an event.
• They can occur naturally or though human cause.
• An event only becomes a hazard when it is a threat to people
• A disaster only occurs when a vulnerable population is exposed to a hazard
• Degg’s model is a representation of this concept as it shows the crossover of a hazardous
event and a vulnerable population amounting to a disaster.
• Natural hazards and their e ects on people tend to have the following characteristics;
• Clear origins and distinctive e ects e.g. earthquakes —> collapse of buildings
• Most provide a short warning time before they hit (some no warning)
• Exposure to risk is involuntary, however, less developed countries are often at greater
risk
• Most losses to life and damage to property occur shortly after the event although he
e ects of a hazard can be felt for a long duration
Hazards are classi ed into three major types; geophysical, atmospheric and hydrological.
However, they can often be a mixture e.g. a tropical storm could be a hydrological-atmospheric
hazard or a ‘hydrometrical’ hazard.
Risk and vulnerability
Risk is the exposure of people to a hazardous event presenting potential threat to themselves,
their possessions and the built environment in which they live.
People, however, consciously put themselves at risk due to;
1. Hazard events are unpredictable - frequency, magnitude and scale can’t be established prior.
2. Lack of alternatives - social, political, economic and cultural factors mean people cannot
uproot themselves from one place to another and give up their homes, land and employment.
3. Changing level of risk - places were once safe and over time have become more of a risk,
deforestation for example could result in more ooding from torrential rain associated with
tropical storms leading to the increased likelihood of landslides.
4. Cost/bene t - there are many hazardous areas that o er advantages that in peoples minds
may outweigh the risk of a possible natural hazard
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, Hazard perception
People have viewpoints of how dangerous hazards are and the risks they pose. The perceptions
are dependent on lifestyle factors - cultural and economic elements.
1. Wealth - wealthier people may see the hazard as smaller as they are less vulnerable and have
the ability to evacuate or build stronger houses. However, wealthier people may also see
themselves as more vulnerable as they have more to lose - property damage, nancial loss.
2. Experience - someone who has experienced more is likely to understand the full e ects.
However there are also studies that people have an optimistic outlook of ‘lightening never
strikes the same place twice’.
3. Education - a person who is more educated will understand the full e ects and how
devastating they can be, whereas someone less educated will not and therefore may not
evacuate.
4. Religion and beliefs - some may view hazards as put there for a reason by god, or being part
of the natural cycle so may not see them as negative. However, those who strongly believe in
environmental conservation may see hazards as huge risks, especially hazards becoming
more frequent due to climate change.
5. Mobility - those with limited access to an escape may see hazards as greater threats than they
are.
Hazard response
1. Fatalism - hazards are uncontrollable and any losses should be accepted as there is nothing
we can do to stop them.
2. Prediction - use scienti c research and past events to predict when a hazard may take place
so that warning can be delivers and the impacts of the hazard can be reduced.
3. Adaptation - attempting to live with hazards by adjusting lifestyle houses so that vulnerability
is lessened
4. Mitigation - strategies to lessen the severity of a hazard e.g. sandbags to o set ooding
5. Management - coordinated strategies to reduce the hazards e ects - includes prediction,
adaptation and mitigation.
6. Risk sharing- form of community preparedness where the community shares the risk posed
by a natural hazard and invests collectively to mitigate the impacts of future hazards.
e.g. New Zealand is a multi-hazardous environment where the Canterbury earthquake 2010 cost
thee country 20% of it’s GDP. There are now attempts to share the risk by insurance investment
so strategies can be put in place before disasters rather than after.
Aspects of hazards and their e ects on human response
Frequency - incidence of a hazard which is not a ected by the strength, just how many times it
occurs. Low incidence are harder to predict and have less management strategies in place
meaning the hazard could be catastrophic when it does occur.
e.g. there are 36 recoded earthquakes since 1500 that were a magnitude of 8.5 or higher.
Distribution - Where a hazard occurs geographically - usually areas of high hazard distribution
will be adapted to the landscape.
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