Induced Seismicity of the Bachat Coal Mine and the Stress State of the Earth’s Crust

A man-induced seismic activation occurring near the Bachat open-cast coal mine in Kuzbass is studied. The Bachat earthquake of June 18, 2013 ( M L = 6.1) is the world’s largest man-made earthquake related to the extraction of solid minerals. It created a powerful aftershock process. More than 3000 earthquakes have been recorded. It was found that the seismic process in the area of the mine as of 2020 is continuous and non-stationary: there are periods of background seismicity with relatively small and infrequent events, and periods of activations with earthquakes that are felt throughout the entire Kemerovo region ( M L ≥ 4), and an increased (by 2‒3 times) frequency of small events. The duration of seismic activations is 1‒3 months. Focal mechanisms of 76 events were determined for the mine area. The fact of mismatch between the model of the stress state of the Bachatsky open-cast coal mine area as recovered from the mechanisms of aftershocks and the mechanism of the main shock of the Bachat earthquake is found.