A macroseismic approach for the evaluation of the seismic risk

The evaluation of seismic risk associated with existing buildings and the related identification of the most suitable strategies for its reduction are extremely essential topics, especially in the framework of the protection of human lives and of the optimal use of the limited resources available. While advanced and reliable methods for the assessment of seismic vulnerability of buildings are nowadays available in the literature, a global approach that takes into account all the parameters related to the seismic risk, exposure, hazard and vulnerability, is not precisely defined. In the current adopted methods, the risk is usually expressed in terms of expected annual loss and it can be evaluated as an integral of the product between the functions of the seismic vulnerability of the building, the site hazard and the exposure (usually in terms of direct losses). Even if such types of approach are exact from a theoretical point of view, the precision and reliability of the results depend on the knowledge level of the probabilistic distribution of all the factors influencing the risk. In this paper a new proposal for the evaluation of the seismic risk, expressed in terms of risk classes and based on a macroseismic approach, is described.