Ground-motion prediction equations for induced seismicity in the main anticline and main syncline,Upper Silesian Coal Basin,Poland

The purpose of the research was to determine parameters of ground-motion models for two areas characterized by considerable induced seismicity and different geology. Fifty-nine events collected from surface seismological stations of coal mine “Bielszowice” (at the Main Anticline, South Poland) and 144 events from coal mine “Ziemowit” (at the Main Syncline, South Poland) were used for computation. For both areas, simple ground-motion prediction equations (GMPEs) without site effects were derived, but the model was acceptable only for “Bielszowice” area. The GMPE was calculated once again for “Ziemowit”, but this time we took into consideration the amplification coefficient, which significantly improved the model solution. Finally, the theoretical value of amplification was calculated. Knowing that the amplification is associated with subsurface layers, we used three different models of overburden: (i) with Quaternary sediments only, (ii) with a complex of Quaternary-Tertiary sediments, and (iii) with a complex of Quaternary-Tertiary-Triassic sediments and Carboniferous as a basement. Usually, the amplification of vibrations appears in the Quaternary sediments. However, theoretical calculations of amplification were consistent with the results obtained from GMPE when a rigid Carboniferous substratum was applied.