Vulnerability assessment and earthquake damage scenarios of the building stock of Potenza (Southern Italy) using Italian and Greek methodologies

The prevailing Italian and Greek methodologies for seismic risk assessment are used herein to construct loss scenarios for the building stock of a small city (Potenza, Southern Italy). The inventory of buildings of interest is obtained from a survey carried out after the 1990 earthquake that struck Potenza and its hinterland, subsequently updated in 1999. About 12,000 buildings were surveyed in Potenza, using the Italian first level survey form for damage and vulnerability evaluation. In the Italian methodology, a hybrid technique is set up to evaluate vulnerability, combining an analysis of building typologies with expert judgement. The probabilistic distribution of damage is evaluated by assigning Damage Probability Matrices (DPMs) from the literature. Besides the vulnerability classes A, B and C of the MSK-scale, the class D of the anti-seismic buildings is considered and the relevant DPM is defined. Damage and economic loss scenarios relevant to dwelling buildings are constructed for three reference earthquakes. Next, the hybrid methodology for seismic vulnerability assessment of reinforced concrete (R/C) and masonry buildings developed at the University of Thessaloniki (Greece) is applied to the same building stock. The methodology combines available statistical data of damage collected after past earthquakes with a systematic nonlinear analysis of various “model buildings”, representative of several vulnerability classes. Similarities, as well as discrepancies, between the two methods are discussed in the light of the obtained results, and possible sources for the discrepancies are suggested.