Natural hazards

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Natural hazards

There is an extremely wide range of natural hazards, some of which are increased due to the actions of man. It is important that for your exam you are able to relate to named examples to show understanding of the topics you have covered. Examples will be referred to in the revision guide but these are really the bare minimum.

Physical hazards include events such as:

  • earthquakes
  • volcanic explosions
  • flooding
  • drought
  • tropical storms
  • landslides.

There are obvious links between hazards, for example, a hurricane may cause flooding, (Hurricane Mitch - Nicaragua) whist a volcanic eruption may lead to a landslide.

Hurricane Mitch

In order for a physical event or process, such as an earthquake to be hazardous there must be the potential for some loss of life. For example, there are some uninhabited volcanic islands, if they erupt they are not strictly hazardous as no loss of life occurs.

It is generally felt that that the less developed a country (LEDC) is the more damage, both economically and in terms of loss of life the hazard causes. There are several reasons for this:

1. Population LEDC's have denser populations.
2. Finance LEDC's do not have the financial clout to demand strict building legislation codes, unlike places such as USA.
3. Education People in MEDC's such as Japan and the US are educated as to what to do in the event of a hazard, and where they can go, thus reducing the vulnerability of the population.
4. Insurance Closely linked to finance. Homes in MEDC's can be insured against damage from hazards Offsetting the cost of rebuilding.
5. Economy Many LEDC's are dependant on a cash crop economy. If a hazard wipes out their entire crop, then their whole economy will suffer.
6. Infra-structure MEDC's are highly organised regards emergency services, and communications to ensure the population in need of help receives this as quickly as they possibly can reducing the spread of disease and death.

The general rule is that the more people there are and the more vulnerable they are to a disaster the greater its impact will be.

Impacts of hazards can be increased by human activity. For example, heavy rainfall is more likely to lead to flooding if vegetation has been removed from hill slopes. Many people in Bangladesh choose to live in the low-lying Ganges Delta as it provides good farming land, but it is the area most vulnerable to flooding.

The location of hazards is not random (see later maps). Areas vulnerable to tectonic activity are usually found on or near to plate boundaries. For example, Japan has a lot of tectonic activity and is situated on the boundary between the Eurasian and Pacific plates.