Holistic evaluation of the seismic urban risk using fuzzy set theory

Risk is defined, for management purposes, as the potential economic, social and environmental consequences of hazardous events that may occur in a specified period of time. From the perspective of this paper, risk requires a multidisciplinary evaluation that takes into account not only the expected physical damage, the number and type of casualties or economic losses, but also the conditions related to social fragility and lack of resilience conditions, which favour the second order effects when a hazard event strike an urban centre. The proposed general method of urban risk evaluation uses the fuzzy sets theory in order to manage qualitative concepts and variables involved in the evaluation. Finally, the method is applied in its single hazard version to the holistic seismic risk evaluation for the cities of Barcelona (Spain) and Bogota (Colombia).