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 Hazards Cyclonic Storms (hurricane) Tornado Severe Storm Flooding Drought Wildfire Severe 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 Disasters 4) 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