Decision support tools for urban contingency policy: a scenario approach to risk management of the Vesuvio area in Naples, Italy

Contingency management, in particular the management of unanticipated events outside the control of an ordinary planning system, has in the last 50 years become an important and frequently debated issue in the scientific literature on complex systems management under risk conditions. The urban system can be regarded as such an open complex system where external events, not always foreseeable with a closed system’s model, may strongly impact on the internal dynamics of an urban area. Conventionally, planning the future presupposes collecting information and analyzing it rationally in order to control for unexpected contingency events. But it is an important question in the field of urban planning, how proper strategies can be developed to deal with external uncertainty and shocks that transcend the imagination of policy-makers. How should decision-makers respond to such unforeseen jumps in a system? The aim of this paper is to present and apply a new scientific decision support method based on the future studies literature, with the aim to help decision-makers in the strategic management of uncertainty and risk in order "to anticipate the extraordinary events correctly in order to act more effectively" (Godet, 1987). In particular, we will deploy here the scenario methodology in combination with multicriteria analysis and fuzzy set theory, as a useful