Understanding Disasters: Concepts and Terminology
Hazard, disaster, risk: the exam's core distinction
This domain tests whether you can separate four words that ordinary speech uses interchangeably but disaster management does not.
- Hazard: a natural or human-made event that may cause harm - an earthquake fault, a river in spate, a chemical tanker.
- Disaster: the consequence when that event strikes a vulnerable community and losses exceed its own coping capacity. The standard definition - a serious disruption of the functioning of a community causing widespread losses that exceed the ability of the community to cope using its own resources - should be learnt almost word for word.
- Vulnerability: conditions that make people susceptible - weak houses, poverty, illiteracy, unsafe location.
- Capacity: resources that resist damage - cyclone shelters, trained volunteers, early warning, savings.
- Exposure: people and assets located in the hazard zone.
The relationship is written as Risk = (Hazard x Vulnerability) / Capacity. Capacity sits in the denominator, so preparedness literally divides risk.
Classification
Sudden-onset (earthquake, tsunami, flash flood, cyclone, landslide) versus slow-onset (drought, desertification, sea-level rise). Natural (geophysical, hydrological, meteorological, climatological, biological) versus man-made or technological (industrial accident, fire, road accident, stampede) and sociological (riot, war, displacement). Distinguish prevention (stop the event or its impact), mitigation (reduce it), preparedness (be ready), response (during) and recovery (after).
Worked example
A magnitude 6.5 earthquake strikes (a) a barren island and (b) a densely built town with no building-code enforcement. In (a) there is a hazard but no disaster - no exposure, no losses. In (b) the same hazard becomes a disaster because vulnerability is high and capacity is low. A full-mark answer names hazard, exposure, vulnerability and capacity explicitly instead of writing only earthquake.
Marks-losing traps
Calling a hazard a disaster; writing natural disaster when the disaster is socially produced; claiming the Richter scale measures damage (it measures magnitude, while intensity scales such as MSK or MMI measure effects); reducing risk to hazard plus vulnerability instead of the product-and-division form.