[I was informed this week of the untimely death of a colleague in the community of geography speakers – Dr Martin Degg of the University of Chester. Not only was he a great speaker and geographer, he was also the creator of one of the best-known models in the study of hazards. It is a very simple model, a basic Venn diagram, but it is remarkable for the fact that nobody else had thought to do this prior to the early 1990s. It explains perfectly how a hazardous event becomes a disaster. It is now widely used in classrooms around the world.]
Dr Martin Degg
Hazard v. disaster
First, some basic definitions:
· Disaster - When a hazard has a significant impact on people; a realisation of a hazard.
· Threshold - The magnitude of a hazard above which a disaster occurs.
· Risk - The probability of a hazard occurring and creating a loss of lives and/or livelihoods.
· Vulnerability - The risk of exposure to hazards combined with an inability to cope with them.
· Resilience - The degree to which a population or environment can absorb a hazardous event and yet remain within the same state of organisation, i.e. its ability to cope with stress and recover.
Figure 1. The Degg Model
The Degg model illustrates the interconnections between physical and human factors of Place, and the varying roles of different players. It is a synoptic model, which states that a disaster arises when people (and the degree of their vulnerability) and nature interact with each other. Some have gone on to suggest that there is no such thing as a ‘natural disaster’ - all disasters are ‘human’.
The Degg model links to the hazard risk equation which also helps to understand the relationship between a hazard and a disaster:
Risk = hazard x vulnerability / capacity to cope (or resilience)
Some communities have a high resilience to disasters. They can reduce the chances of a disaster occurring by:
· having emergency evacuation, rescue and relief systems in place
· helping each other to reduce the numbers affected
· having hazard-resistant design or land-use planning to reduce the numbers at risk.
The USGS has adapted, and developed, the Degg model (Figure 2). You will find this diagram on their website. It is a simple model with a worldwide reach.
Thank you, Martin.
Figure 2.
Nice and clear as always thank you