Classifying Natural Disasters
Comparing and Analyzing Natural Disasters
What is a natural hazard or disaster?
Aspects of the physical world that have the potential to cause considerable harm to people.
Caused by natural forces rather than by human action
Can you think of any examples?
What is a natural hazard or disaster? The international Red Cross estimates
that on average over the past 25 years 138,000 people have been killed, 46,000 injured and more than 4 million left homeless each year by natural disasters
These figures do not include the recent tsunami in Asia (273,000) and Hurricane Katrina (1000)
What is a natural hazard or disaster?
Natural disasters often occur in those areas of the world which are heavily populated
Classifying Natural Disasters
Most common way of comparing natural disasters is to measure their impact by the loss of life, the number of injuries and the damage to property that these events cause
Classifying Natural Disasters
We can also measure these disasters by the strength or intensity of the event (for example the wind speed of a hurricane)
In addition, we classify natural disasters by the impact they have on human beings, by the regions in which they occur and their frequency
Classification System
We can classify natural disasters by the chief process or sphere in which it operates
Using this system of classification there are three categories
Classification System
Atmospheric HazardsCyclonic Storms (hurricane)TornadoSevere StormFloodingDroughtWildfireSevere Weather (hot/cold)
Classification System
Biological Hazards
Infectious Disease
Parasitic Disease
Insect Infestation
Plant Disease
Classification System
Geological Hazards
Slide (mud, land, rock)
Volcanic Activity
Earthquake
Avalanche
Tsunami (tidal wave)
Comparing and Analyzing Natural Disasters
Any specific natural disaster can be described by analyzing various factors that determine how great an impact it will have on people
This system recognizes six main factors
Comparing and Analyzing Natural Disasters
1) Frequency- how often is the event likely to happen
2) Duration- the length of time the event lasts
3) Extent- does it affect a wide area or region or a small one
Comparing and Analyzing Natural Disasters4) Speed of onset- happen quickly with no
warning and over quickly or build slowly before the peak period
5) Spatial dispersion- the area that is likely to be affected by a particular event
6) Temporal spacing- how hazards and disasters occur in time; are they random or do they occur within a cycle