Evaluation of the forecast reliability of site effect for regional mining tremors

Abstract

It is obligatory for Polish underground mines of hard coal and copper to prepare long-term exploitation projects for 2 - 5 years. All the natural hazards, including seismic ones, that may occur have to be taken into account in such projects. In the case of mining seismicity the forecast of site effect plays an important role. To recognize the reliability of this forecast for strong regional mining tremors special methodology was used. The peak ground velocity and peak ground acceleration, recorded after the occurrence of a regional tremor by surface seismometric network stations, were compared with the distribution of the forecast values of these parameters determined for similar seismic energy. Differences between these values are the basis for the evaluation of the reliability of the forecast site effect. The practical implementation was presented with the tremor of seismic energy E = 5.108 J (ML = 3.63) which occurred on 18th January 2018. The small value ΔPGVHmax (4%) of the difference between the recorded PGVHmaxrec and the forecast values PGVHmaxpr confirms that the measurement values correlate well with the forecast values. The difference value ΔPGAH10 for the peak ground acceleration equals 31% showing a worse correlation with the forecast data.

Keywords

• Mining tremors
• Site effect
• Velocity
• Acceleration