Seismic assessment of consequences in the building stock in Bulgaria based on statistical calibration of public data

A generally accepted step to reduce the consequences of strong earthquakes and be prepared to face them, is to assess the possible damages and undertake countermeasures proactively. The aassessments are made based on analyses of seismic hazard and vulnerability of building structures. To collect the data about the buildings requires a lot of financial resources and time especially for a large-scale study. In this paper an assessment of the possible consequences in the building stock of a town in Bulgaria is performed by using public data. Some problems arising in the use of the available public data for the building stock in Bulgaria collected by the National Statistical Institute are discussed. A statistical approach is applied to calibrate this data for the buildings to classify them according the building typology and period of construction, which are main factors that determine their vulnerability. The consequences to the building stock has been evaluated with public data for several large cities in Bulgaria. Different approaches for the relation between the earthquake intensity and the level of damage are applied. Comparison of the calculated damages in the building stock of the town of Pernik and the observed damages during the 22 May 2012 earthquake is made. The results are discussed in view of applying public data for the building stock to estimate possible consequences from a strong earthquake in large urban areas.