Vulnerabilità Urbana e Mappe di Rischio per la Prevenzione Sismica e la Gestione dell'Emergenza

The quantitative measure of seismic vulnerability is a necessary requirement for prevention and for an optimal emergency management. Before L'Aquila's earthquake in 2009, the National Civil Protection, in collaboration with the University of L'Aquila, developed a model to evaluate the criticality seismic of urban centers by using a multidisciplinary approach. The study has led to the definition of a urban vulnerability index, that allows to identify the most critical urban centers and the problematic elements, in order to establish a hierarchy for preventative measures and for an efficient emergency management. One of the features of this evaluation is that it allows a simultaneous analysis of the multiple factors involved in risk assessment. After the seismic event occurred, same tests have been made to verify the validity of the model on the part of buildings, by comparing the criticality evaluated and damage suffered by the buildings, taking into account the local effects resulting from operations of microzonation. The seismic vulnerability index is calculated as the weighted sum of same parameters, that represent a building feature which can affect the structural response under earthquake ground motion. Therefore the influence of each parameter and their respective weights on the model have been analyzed. Sensitivity and Factorial analysis were performed to understand the model parameters that most affect structural vulnerability using the damage date collected after L'Aquila earthquake. Furthermore a probabilistic correlation between the Vulnerability Index and the possible damage to the buildings resulting from an earthquake is provided. Moreover the vulnerability model is implemented in a probabilistic and quantitative risk analysis using the Event Tree Analysis Methodology. As for the test performed, the methodology has a good level of confidence in the modelling of the vulnerability of the buildings so it can be successfully used for seismic risk assessment, necessary for seismic safety and emergency management.