The use of GIS as tool to support Risk Assessment

Risk assessment is a complex issue aiming at evaluation of different aspects of disaster damages. Traditionally, risk analysis relies on mathematical model to establish the likelihood of a given event occurring with a given degree of intensity in a given site. The major limitation of this type of approach is the fact that the field of risk necessarily entails uncertainty and it is not therefore always possible to make realistic hypotheses about possible future scenarios. Therefore, a new approach is required, that can take into account social, economic, cultural, and political aspects that are not generally considered in traditional assessment methods, but that serve to define the capacity of response of a territorial system to a disaster. In this paper we present a new approach, according to which the assessment process breaks down the principal goals into a hierarchy of lower level sub-goals. Each element of the hierarchy is assigned a local weight that evaluates the importance of that element not in overall terms, but only in relation to the supra-ordinate element with which it is compared.