Calibration of vulnerability and fragility curves from moderate intensity Italian earthquake damage data

The objective of this work consists in the calibration of vulnerability and fragility curves for the main masonry building classes detected in Lunigiana and Garfagnana (north-west of Tuscany, Italy). The large-scale procedure aims at providing damage and unusability scenarios starting from a seismic hazard map and a typological/structural characterisation of the building stocks lying in the different sub-municipal homogeneous areas. The damage and vulnerability data collected in more than 3000 AeDES survey forms of rapid damage assessment, filled out in Lunigiana and Garfagnana after the June 21, 2013 Earthquake, along with the information derived from a fast visual screening of the facilities, have been processed to develop a specific database in a Geographical Information System (GIS) environment. The latter and the shakemaps downloaded from the National Institute of Geophysics and Volcanology have allowed to compare the actual fragility of the building sample with the expected one, which has been evaluated according to the Macroseismic Method. The study concludes with a conservative proposal of modification for the vulnerability and fragility curves, for low values of EMS-98 macroseismic intensity (IV-VI) or PGA (0.04 g–0.30 g), and the identification of empirical correlations between the percentage of unusable buildings and the EMS-98 damage levels or the shaking parameters.