Statistical seismic vulnerability of New Zealand unreinforced masonry churches

During the 2010–2011 Canterbury earthquake sequence, extensive damage occurred to NewZealand historical and architectural heritage, and particularly to unreinforced stone and clay brick masonrychurches. Of 309 unreinforced masonry churches identified nationwide, a sample of 80 buildings belonging tothe affected region was studied and their performance analysed statistically. Structural behaviour of religiousbuildings was described in terms of mechanisms affecting the so-called macro-elements, being portions of thebuilding behaving more or less independently. Discrete local damage levels were correlated with macroseis-mic shaking intensity through Damage Probability Matrices. Multiple-linear regressions were also considered,accounting for additional modifiers increasing/reducing the vulnerability of the macro-elements. Results showthe relevance of the proposed multiple-linear regression models for the national heritage of churches and theadvisability of extending mechanism-based regressions to other countries besides New Zealand