A correlation between damage and intensity on old masonry churches in Colima, Mexico by the 2003 M7.5 earthquake

• Seismic vulnerability assessment of 15 historical churches of unreinforced masonry.
• Comparative between methods for assessing the seismic vulnerability of churches.
• Two damage scenarios on old masonry churches before and after a certain earthquake.
• Correlation between damage and intensity on the two different damage scenarios.
• Calibration of observed damage degree with a European Macroseismic Scale.

Strong damage was observed in Colima Mexico on most of the cultural patrimony (mainly churches) after the 2003 M7.5 earthquake. In order to find a correlation between the observed damage on the historical buildings and the earthquake intensity, the vulnerability is assessed by qualitative methods, including the vulnerability class method (VCM) and the vulnerability index method (VIM). The latter method is modified and adapted in this research to assess the seismic vulnerability of historical buildings such as churches and cathedrals located in areas from high to very high seismicity. The results are intended to serve as preliminary indicators of expected damage levels that allow the local authorities to take measures oriented to disaster prevention. The assessment using both methodologies is developed on 15 historical masonry churches, most of them from XIX century. With the results, a correlation between damage and intensity taking into account a Macroseismic Scale is developed and the qualitative methodologies to assess the seismic vulnerability of historical constructions are compared each other.