Geophysical Institute of Bulgarian Academy of Sciences, Sofia, Bulgaria

The capital of Bulgaria, Sofia, is situated in the center of the so-called Sofia area. This is the most populated industrial and cultural region of Bulgaria that faces considerable earthquake risk. We apply a version of machine code EQRISK for hazard assessment of the Sofia area according to the Cornell-McGuire approach. The probabilistic seismic hazard analysis is based on a simplified seismogenic model, which is derived from seismic zoning of Bulgaria. We show, using a Monte Carlo approach, that uncertainties in seismic input have a relatively small effect on the PSHA output, especially when compared with uncertainties associated with the attenuation relationship. Our PSHA map shows that a 10–3 annual probability of the PGA exceeds 0.3 g in much of the Sofia area