The aftershock sequence at a deep nickel mine: temporal and spatial distribution, magnitude distribution, and aftershock decay following major events

Mining-induced seismic events greatly threaten safety of underground workers and studying major seismic events would help mitigate hazards in deep mines. Characterizing the aftershock sequence of major events can contribute to developing a reentry protocol after major events occur at mines. This study uses two major events and their aftershock sequences at Creighton Mine to investigate properties of aftershock sequences focusing on the magnitude of completeness and aftershock decay pattern. Two major events with moment magnitude 3.1 and 1.4 are analyzed, respectively, and their aftershock sequence are examined in this study. The optimal magnitude of completeness is rigorously determined by evaluating the goodness of ft using the maximum likelihood method. Then, parameters of aftershock decay using the MOL are estimated. We identify that the p-value of the two studied events is slightly larger than 0.8. This parametrization process using the MOL can assist in better understanding aftershock sequences of mining-induced major events and therefore mitigating seismic hazards in mining by potentially helping establish a reentry protocol based on the seismicity dropping below a certain rate. For establishing a reentry protocol, the study of the two events can be considered as a methodological work and a future statistical work for many events with different magnitudes and locations to establish the range of the MOL parameters is needed.

---

Opracowanie rekordu ze środków MEiN, umowa nr SONP/SP/546092/2022 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2022-2023).