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Disaster onset

Disasters can take several shapes. They can be man-made, natural or a combination of both.
© Coventry University. CC BY-NC 4.0

Over and above describing or classifying disasters on the basis of their triggering hazard (if obvious), ie, disasters resulting from a flood or transport incident.

There are two distinctions of disaster ‘types’, Sudden onset and Slow onset. The difference between each disaster type depends upon firstly how they affect the given situation and location. Secondly each disaster type will differ from how the disaster impacts, how it is assessed (or not), and how and when it is managed.

Sudden onset

A sudden event occurs with little or no warning and has immediate adverse effects on the human population, activities, economic system and natural environment. Examples of this type of disaster would be earthquakes and hurricanes.

Slow onset

This refers to a situation in which the ability of people to sustain their ‘usual’ activities slowly declines to a point where survival is jeopardised. Such situations are typically brought on by environmental, social, economic and political changes.

The task below will give you the opportunity to define the range of disasters into sudden onset and slow onset.

Your task

Step 1
In the table below, classify the following as either natural or man-made.
Terrorist attack, earthquake, war, flash flood, epidemic, cyclone, drought, volcano, famine, civil unrest, plane crash and chemical spill.
Step 2
Subdivide your choices into sudden onset and slow onset types of disasters.
  Natural Man-made
Sudden onset    
Slow onset    
Step 3
Share your thinking around your reasons for choosing to categorise these events as you have. Discuss the implications of both slow onset and sudden onset for the disaster response and include case study examples.
© Coventry University. CC BY-NC 4.0
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