Abstract:
Studying of the space-time distribution of earthquakes is very important for understanding the physics of the earthquake generation process. The 2006 MW4.7 KARDZHALI earthquake was followed by an intensive aftershock activity. We analyze the space-temporal pattern of earthquake distribution in the aftershock sequence of the main event. We find that both space and temporal distribution of aftershocks shows non-random features.
In this study P- and S-wave spectra for earthquakes from the seismic cluster (main earthquake – aftershocks) are generated. Earthquake parameters: seismic moment, source radius, stress drop are estimated applying Brune model for the MW4.7 quake and five aftershocks with magnitude МW in the interval 3.3 ÷ 3.7. The estimated stress drop value for the main event is within the expected range for moderate earthquakes (43 bars for the P-wave and approximately 65 bars for the S – wave).