Assessment of Microseismic Events via Moment Tensor Inversion and Stress Evolution to Understand the Rupture of a Hard–Thick Rock Stratum

We evaluated the spatiotemporal evolution of microseismic (MS) sources generated by multiple fracturing of a hard and thick Jurassic rock stratum in the 93_upper24 working face of the Nantun coal mine, China. Moment tensor inversion, stress field analysis, velocity tomography, and stress inversion were used to reveal individual rupture types and the failure process of the hard rock stratum in the working face during the mining operation. We simulated the change in Coulomb stress before and after the occurrence of mining-induced tremors, and analyzed its impact on the stability of the surrounding rock close to the working face. Our results demonstrate that the static Coulomb stress change computation is an efficient tool to predict the evolution of subsequent MS events patterns. The outcome of this work allows to identify and better understand the failure mechanism within a hard and thick Jurassic rock stratum during the mining operation, and can be an interesting approach in improving mine safety in similar environments.

Highlights

Induced microseismic events (evolution of hypocenters, energy, and source types of events) are used to characterize the failure process in a hard–thick Jurassic rock stratum during mining operations.