The May 22, 2012 Mw = 5.6 Pernik Earthquake –
Local Effects and Seismic Impact on Sofia city

K.D. Hadjiyski, S.M. Simeonov, E.A. Botev
National Institute of Geophysics, Bulgarian Academy of Sciences, Sofia

ABSTRACT:

On May 22, 2012, a shallow earthquake of Ms=5.8 (Mw=5.6) hit Pernik region and caused damages on many buildings in the town of Pernik and near-by villages. The maximum observed intensity is of VIII degree EMS. This seismically calm area has produced the strongest Bulgarian earthquake for the latest 80 years. A short seismological insight of the source activity is followed by an engineering analysis and evaluation of the seismic impact for Sofia city, only about 20 km away. The array of recorded data by the local digital SGM Network of Sofia is exploited to obtain input characteristics, relevant to the aseismic design of structures. Processed data for some representative recording spots is extracted, submitted and discussed. Destruction and damages induced by the earthquake in the Pernik area are illustrated and the building vulnerability aspects are considered. Some inferences, conclusions and recommendations about seismic risk mitigation are made.

Keywords: earthquake magnitude and intensity, spectral analysis, impact evaluation, vulnerability of structures