Risk in regard to disaster is the likelihood or probability of harmful consequences happening; awareness of risk gives us the ability to define what could happen in the future, based on a range of possible outcomes. The ability to understand and assess risk depends on many factors including the amount and reliability of available information, and the perceived perception of risk (UN/ISDR 2004:36, Alexander 2000:10). Perception or awareness is very important in assessing risk as a whole, as it requires prior knowledge of hazard and vulnerability, the other major concepts of effective disaster management (UN/ISDR 2004:36). Alexander (2000:11) highlights that risk is an abstract concept that only comes into being when mobilised by external forces, in the case of disaster this is hazard.
The term vulnerability in the context of disaster was first used by engineers to considering the resilience of different forms of construction. In the socio-economic context vulnerability' is a set of conditions which adversely affect people's ability to prepare for, withstand and respond to a hazard (Nivaran 1998). Vulnerability is complicated because it is founded on so many constantly changing factors, and linked to the complex, dynamic and diverse workings of human society.
Vulnerability and risk are closely related with vulnerability being a reflection of physical, social, economic and environmental conditions present that increase susceptibility to hazards. Risk combines this with the probable size of the impact, the type and magnitude of the hazard (Alexander 2000).
Hazards are extreme events with a negative