Seismic vulnerability of churches: a territorial knowledge approach

This paper is an overview of a PhD thesis developed between Italy and Québec, Canada. It focused on the seismic vulnerability of churches, proposing a territorial approach for its assessment in the perspective of conservation. Churches have shown being highly at risk when facing earthquakes, due to their intrinsic structural characteristics. In Italy, since the 1976 Friuli event, methods for vulnerability assessment, for identification of macro-elements and the corresponding damage mechanisms, and for damage classification were developed. The approach proposed in the thesis consists in the identification of specific aspects, such as local construction materials and techniques and seismic awareness locally developed over time and influencing construction practice, to be included within a vulnerability analysis to complement the current assessment procedures based mainly on damage pattern recognition. These specific aspects are labelled with the term ‘territorial specificities’ and they are related to the territory and to the building characteristics. Case studies from the province of Mantova and Macerata and a specific case of church-fortress, the Arabic-Norman, in Eastern Sicily, were examined leading to propose a territorial approach for the seismic vulnerability assessment of churches ending with the elaboration of a Territorial Specificity Knowledge Form (TSK-Form) for vulnerability surveys. Finally, in order to test the proposed approach, a group of churches from Montreal (Québec) were surveyed pointing out how the different construction culture and seismic awareness have led to build churches with features dissimilar from the Italian ones. The method showed its validity being able to interpret the vulnerability of these churches in their diversity. Finally, the collected information was formalized in a GIS workspace. This last step of the procedure aims at making the information available to Authorities that operate in the territory aiming at setting strategies for damage prevention and conservation. Today, the territorial knowledge approach is applied by a group of researchers in Québec, as a consequence of this investigation.