La fragilità delle fortezze. Nuovi strumenti per proteggere il patrimonio dell'architettura fortificata italiana dai terremoti.

The present paper proposes the use of GIS for the application of the phenomenological approach to the analysis of the seismic behaviour of fortified historical buildings. This approach focuses on the observation and classification of the real damage as a first step for identifying the recurring vulnerabilities, specific for each masonry building typology. The GIS has proven to be a powerful instrument to collect and manage this type of information on a large number of cases. The main earthquakes which struck Italy in the last 40 years (up to the recent Central Italy earthquake) were analysed. Through the use of shake maps, the seismic actions were connected to the damages suffered by castles and fortresses, inspected with a wide archival research. The statistical analyses on these data allow to plan focused preventive interventions, in relation to building features and seismic hazard.