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Year 9 - Risky Earth - What are hazards?

What are Hazards?

A Natural Hazard is any natural event that has the potential to endanger human life, the economy and property. This unit is all about the management of hazards. For each hazard you will look at its causes, the effects it has (on people, the environment and the economy) and how the hazard is managed (in terms of prediction, prevention of damage, preparation of communities). You will be expected to do this for both MEDCs and LEDCs. You can visit the NASA hazards page here.

Natural hazards are slightly different to Human RISKS. Risks can also include any human hazards as well as naturally occurring events. This means that crime, wars and diseases can count as human risks but not natural hazards. There are also different types of hazards and they can be classified along the following lines;

Atmospheric hazards - those hazards to human health and wealth that are created in the atmosphere -including tornadoes and hurricanes

Geological/tectonic hazards - those hazards that are created by the movement of the Earth's tectonic plates such as earthquakes and volcanoes, or the movement of rocks and soil such as mudflows and landslides

Water based hazards such as flooding and coastal erosion

Human hazards such as crime, wars and diseases

Biological hazards - these are hazards posed by living things, such as diseases, plagues of locusts and infestations of animals

Because the focus of the unit is on how human beings adapt to and adjust to hazards, you should be familiar with the following terms;

Direct or Primary effects - this is an impact or effect of a hazard that occurs as a direct consequence of that hazard. For example, roof tiles being blown off in a hurricane or flooding after a period of prolonged rainfall.

Indirect or Secondary hazards - these are hazards that result from an initial event, but happen at a later date. For example, mudslides are often common after hurricanes due to the rainfall brought by hurricanes and elevated river levels, but are not directly caused by that hurricane. Also, post hurricanes, diseases such as Malaria and Typhoid can arise in unsanitary conditions (such as standing dirty water) and are a secondary impact or effect of the hurricane passing. Find out more about secondary flooding hazards.

Hagar cartoon


Aid - this is any form of help that is offered during disasters. Aid can take make forms and not all of it is free. Aid can come from Governments such as the UK, from individual donors such as Bill Gates, from Charities that we contribute to (such as Oxfam, the Red cross, Christian Aid, CaFOD etc) and from international organisations such as the United Nations (UN). Aid can be given freely where the countries suffering the disaster receive the help free of charge, or the country may have to give the money back (interest might even be added) at a later date once the crisis region has recovered. Aid can also take many forms, from money, to technology, to rescue teams (e.g. sniffer dog teams to find people in collapsed buildings during earthquakes), to skilled people such as doctors, top food and water aid. Often the military of countries play a vital role in distributing aid and rescuing people. Richer countries (MEDCs) tend to use their own resources for aid and have contingency funds for this but can accept help from other countries. Poorer countries (LEDCs) tend to rely more on foreign international aid than their own resources.

The reactions of people to hazards - 4 "f"s

People have 4 basic reactions to hazards, all of which are perfectly natural and occur within the brain. Different people react differently when threatened and the common reactions are;

Freeze/Fright - this reaction is where people just become incapable of reacting due to the immensity of the situation. In the Boxing Day Tsunami of 2004 many people stood in fascination on the beach and just froze as the waves thundered towards the shore.

Flock - People can also act like seep during natural hazards and "flock" together. Human beings in general are social animals that see security and safety in numbers.

Flight - The most obvious reaction to a natural hazard is to fly or run away! This can be an organised event if there is enough notice or it can be chaotic and haphazard -"everyman for himself"

Fight - People can also fight against the hazard to protect themselves and their property - sandbagging during flooding is a good example of this. The reaction of Governments and Authorities to hazards - the 3 "p"s The reactions of governments are vital for reducing the impact of natural hazards, the recent hurricane in Burma (2008) and the earthquake in China showed 2 contrasting examples of how governments react. The Burmese were very slow to accept any sort of international help, whilst the Chinese were surprisingly open.

Preparation - governments might consider how they can educate and prepare their populations for a disaster, so that they know what to do in a hazardous event. Also, governments can put into place laws and building codes to govern what can be built and to what standard, so that hazard impacts from hurricanes, earthquakes etc can be reduced.

Prediction - this is basically the mechanism by which we try to forecast when and where a hazard will occur. There are a huge range of prediction methods now for a huge range of hazards, think about the Avalanche risk charts you may have seen whilst skiing. We can use satellites, river flow meters, sulphur dioxide meters, tilt meters etc. to predict different hazards. We are better at predicting some hazards such as flooding, than we are others, such as earthquakes, because some of the warning signs are clearer and because of the amount of response time to each hazard.

Prevention - these are the methods that we can put into place as human beings to either prevent the hazard entirely or prevent some of the negative impacts of a hazard. Some hazards such as forest fires can be prevented, by using fire breaks and prescribed (deliberate fires) major forest fires can be stopped. Other hazards cannot be prevented, such as Hurricanes. However, we can prevent some of the flooding during hurricanes by having correct drainage systems and coastal defences.

Find out more

1) Play the stop disasters game from the United Nations Cyber School bus site! These games are highly addictive!

2) Using the NASA Earth Observatory website, research one current natural hazard of your choice.  The link takes you to a hot linked map and you can look at amazing images of the hazards taken from space!

3) Try an investigation from Natural

4) Find out more from NERC, the National Environmental Research Council of the UK - this site includes pages on most hazards, with a British outlook

5) Watch video 1  and list as many hazards as possible

6) Try the Venn diagram and scatter game at the base of the page 

  Hurricanes Volcanoes Earthquakes
Prediction methods used Look at the bottom of this BBC web site page
science of tracking hurricanes;
Thinkquest site on the topic
Brilliant account from GeoBytes
Interactive site on Volcano prediction
Earthquake prediction from Wikipedia
USGS site on earthquake prediction
Prevention methods used Look at this website
A full guide from the CDC on hurricane damage prevention
Information on how to prevent damage from a Volcano How to prevent Earthquakes (?)
Preparation National Hurricane Centre preparation  info Preparing for Volcanic eruptions by the USGS Excellent site from San Francisco on preparing people.
See an animation of how building design can prevent damage.
Wikipedia's entry on building design



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