Study on the rupture properties and automatic identification model of micro-earthquakes and blasting events in a coal mine

Abstract

Source location is the key step of microseismic monitoring. The monitored microseismic signals are often mixed with unrecognized blasting interference signals, which affect the results of microseismic monitoring and location. Therefore, it is very important to extract the characteristic parameter information to identify the microseismic signal and blasting signal. The rupture processes during micro-earthquakes and blasting events in a coal mine are complicated and have different characteristics, which seriously affects the safety of coal mine. To quantify the seismic source properties of micro-earthquakes and blasting events in coal mines, and further distinguish between micro-earthquakes and blasting events, the source parameters of micro-earthquakes and blasting events in coal mine were obtained, and the differences between micro-earthquakes and blasting events were investigated by comparing the characteristics of their respective source parameters. Firstly, the corner frequency f0, spectral level Ω0, seismic moment M0, source energy E, source radius R, stress drop △σ, apparent stress σa, and magnitude (Mw and ML) of micro-earthquakes and blasting events in Qianqiu coal mine were calculated using the Brune model and grid-search method; then, the relationship between seismic moment and the other source parameters was analysed, the differences between micro-earthquakes and blasting events were studied based on the above source parameters, and the automatic identification model of micro-seismic and blast signals thus established; finally, the local magnitude was calculated and the relationship between moment magnitude and local magnitude analysed. The magnitudes of micro-earthquakes and blasting events are determined based on the calculated Mw and ML. The above analysis can be used to determine and quantify the seismic source properties and scale of micro-earthquakes and blasting events, and further distinguish micro-earthquakes from blasting events effectively to ensure the accuracy of source location and allow implementation of effective control measures.