Seismic hazard assessment for Bulgarian territory based on the method of spatially-smoothed seismicity
© Galina Foteva, Minka Ilieva, Emil Botev
The present paper suggests preliminary maps from the seismic hazard assessment for the territory of Bulgaria based on the method of spatially-smoothed seismicity, initially proposed by Frankel (1995). A modified variant of the method which is applied for the territory of Slovenia (1997) is used in presented work. Four seismicity models are used to characterize the seismic hazard. A combined horizontal peak acceleration ground (PGA) map with 10 % probability for exceedance in 50 years (475 return period) is derived from the weighted mean of the probabilities of exceedance from the four models at each location. The map obtained outline very well the well-known seismic hazardous zones on the territory of the country. On the combined map the highest contour values of PGA for Struma, Maritsa, Western Rhodopes, Sofia, Gorna Oryahovitsa, Yambol, Shabla and Provadia zones are respectively 0,45; 0,35; 0,30; 0,30; 0,25; 0,25; 0,25 and 0,20 g. A worst-case map is constructed also taking into account only the highest values of the probabilistic ground motion from the four models at each location.