Empirical damage and liquefaction fragility curves from 2012 Emilia earthquake data

The study focuses on the effects of liquefaction on structures taken from data on about 1000 private residential masonry buildings located in several municipalities struck by the 2012 Emilia earthquake. Survey data were collected by teams of experts coordinated by the Italian Department of Civil Protection in the immediate post-earthquake emergency phase. They included information on building characteristics and the level and extent of the damage to structural and non-structural components. Furthermore, according to data related to the reconstruction process, information on the liquefaction-induced type and extent of the damage was also collected. Through a comparative analysis of the empirical damage, it was found that liquefaction strongly affected the buildings, confirming its relevance in the damage scenario under specific subsoil conditions. Based on this evidence, the article proposes a correlation between structural damage and liquefaction when it comes to deriving proper preliminary empirical fragility curves. A suitable parameter to define liquefaction effects at ground level is introduced and correlated to damage grades defined according to the European Macroseismic Scale: EMS-98.