Multi-risk Assessment as a Tool for Decision-Making

Abstract

The multi-risk concept refers to a complex variety of combinations of risk (i.e. various combinations of hazards and various combinations of vulnerabilities). For this reason, it requires a review of existing concepts of risk, hazard, exposure and vulnerability, within a multi-risk perspective. The main purpose of the multi-risk assessment is to harmonise the methodologies employed and the results obtained for different risk sources, taking into account possible risk interactions. Given the complexity of processes that the multi-risk problem poses, the framework presented here entails three levels of analysis: the first-level analysis, in which the evaluation of the potential physical damages is performed; the second-level analysis, in which tangible indirect losses are assessed considering the socio-economic context; and the third-level analysis, where a set of specific social context conditions is considered in an indicator-based approach. One of the most challenging elements of the multi-risk assessment is the translation of the quantitative output into useful information for decision-making under uncertainty. This is a critical step to consolidate the importance of the multi-risk analyses and to define their ultimate importance and usefulness for the resolution of critical societal problems. To illustrate the general methodology presented, an example application has been developed in Dar es Salaam (Tanzania), which is one of the case study cities in the CLUVA project.