Abstract:

Laohutai coal mine, located in Fushun, Liaoning Province, has been exploited for almost a century and is one of the mining areas with serious mine earthquake disasters. However, due to the lack of dense seismic monitoring stations, the mine’s microseismic event monitoring capacity is insufficient. In order to  monitor the microseismic activity better, this study carried out  double-difference location of microseismic events in the mining area based on two linear dense seismic arrays deployed in  Laohutai coal mine from November 3 to 25, 2019. The relocation results indicate that the largest event of this microseismic activity was the ML 2.4 earthquake that occurred near  Hunhe fault, with an epicenter depth of 0.5 km. Before the occurrence of the Hunhe ML 2.4 earthquake, the microseismic events of ML >1.0 gradually increased and migrated to the western end of  Hunhe fault. After the occurrence of the Hunhe ML 2.4 earthquake, the microseismic activities in the mining region were mainly concentrated near  F1 and F2 faults in the mining area, and the depth of the epicenter was mainly concentrated between 0.2-1.5 km. The spatial and temporal distribution characteristics of the microseismic events indicate that the microseismic activity in  Laohutai coal mine may be affected by the Hunhe ML 2.4 earthquake, and fault activation may occur in the mining area. Additionally, we speculate that the F2 fault may be a NNW-trending buried fault extending to  Hunhe fault based on the observed distribution of the microseismic relocation.

Key words: Laohutai coal mine, dense seismic array, microseismic monitoring, double-difference location, Hunhe fault, mine earthquake disaster