Open File Report 2024-02

Author(s) Date 2024-04-23

Source mechanisms help understand the faulting behaviour and the evolving stress field in the subsurface. This study investigates the source mechanism of an event with a local magnitude (ML) of 3.7 that occurred near a blasting site, 19 km east of Hinton, central Alberta, on June 25, 2022. The amplitude-based method was used to invert the seismic moment tensor of the event. The amplitudes of compressional P-waves and shear S-waves recorded at multiple seismic stations of regional networks were used in the inversion. The synthetic amplitudes of the ground displacements were computed using ray tracing and a one-dimensional velocity model. Then the solution was found through a least-squares inversion scheme. The inverted moment tensors of the ML = 3.7, June 25, 2022, event were compared with the inverted moment tensors of six suspected blasts and an earthquake (ML = 1.68) near Hinton. The analysis revealed that the ML = 3.7, June 25, 2022, event was a blast, rather than a natural earthquake unrelated to the blasting or an event induced by the blast as initially suspected.

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Bui, H., Stern, V.N., Yusifbayov, J.A., Reyes Canales, M. and Roman, N.L. (2024): Moment tensor analysis for the local magnitude 3.7 seismic event on June 25, 2022, near Hinton, central Alberta; Alberta Energy Regulator / Alberta Geological Survey, AER/AGS Open File Report 2024-02, 27 p.