Earthquake scenarios and population exposure for the city of Plovdiv

Among natural disasters, earthquakes dominate with regard to their social and economic effects on human life and the urban environment. Appropriate risk reduction strategies can be developed only with a better understanding of seismic hazards as well as the population and building growth rates in the corresponding region. In the present study, deterministic and probabilistic earthquake (seismic) ground-motion scenarios are developed and presented for one of the most earthquake-prone cities in Bulgaria, the city of Plovdiv. We apply a method for integrating the spatial distribution of seismic hazards with human exposure to assess hazard impacts. Earthquake scenarios and social vulnerability metrics are combined in a geographic information system (GIS) to identify the spatial vulnerability of the exposed population to seismic risk and the locations for targeting mitigation actions in areas with high exposure and vulnerability levels. The results of our study show that most of the territory of the city is classified at the highest seismic hazard level: PGA 0.2. High and major levels were estimated for the population exposure index (PEI) for nearly 60% of the residential buildings in the city (inhabited by approximately 96% of the Plovdiv population). The spatial distribution of the results is available in GIS format and can be used in scientific and practical applications to reduce the risk and consequences of possible strong earthquakes in future.