GC2022-SG027

Bath law dynamic in mining induced seismicity

Alexander Motorin1, Sergey Baranov1

1Kola Branch of Federal Research Center “Geophysical Survey of Russian Academy of Sciences”

ayumotorin@gmail.com

Using the data of long term seismic monitoring in apatite-nepheline deposits of Khibiny Mountains (Kola Peninsula) we considered the distribution of magnitudes of the strongest aftershocks – depending on the time after the main shock – that occur during the extraction of minerals in tectonically loaded rock massifs. We demonstrated that the distribution of the difference between the magnitudes of the strongest aftershock and the main shock obeys the dynamic Bath law (combination of the laws of Gutenberg-Richter, Omori-Utsu and earthquake productivity), previously obtained for the global and regional seismicity. The main result is the Bath law dynamic is appropriate for mining-induced seismicity in Khibiny massif. This result is not obvious, since in mining-induced seismicity stress relaxation after the main shock is affected by explosions, which also change the local stress field. This feature, absent in natural seismicity, can cause the aftershock decay in a specific sequence to deviate from the Omori-Utsu law. Nevertheless, on average, the attenuation of aftershocks obeys the Omori-Utsu law. This result shows that approaches for assessment of aftershock hazard due to natural earthquakes can be applied to the mining-induced seismicity in tectonically loaded rock masses. The research was supported by the state assignment of the Federal Research Center ”Geophysical Survey of Russian Academy of Sciences” No.075-01471-22.