Rock Fracture Monitoring Based on High-Precision Microseismic Event Location Using 3D Multiscale Waveform Inversion

Figure 7

Location results of the two-stage multiscale waveform inversion for blasting event 2. (a) 2D sliced plane of the 3D velocity model determined by the 18 sensors used in this test event, and location results of waveform inversion in different-scale grids. (b) Locally enlarged map of the FWI iteration location results. The yellow and red stars represent the initial location determined by the 30 m grid search based on 3D ray tracing and the iterative convergence process of source location based on the coarse grid, respectively. The blue stars indicate the iteration processes of location based on the second-stage fine-grid FWI. Moreover, the green and black stars denote the final FWI converged location results and premeasured location of test event 2, respectively. (c) Normalized waveform misfit reduction during FWI iterations; the color of the stars is consistent with the location results. For multiscale waveform inversion, the waveform misfit in each new stage is renormalized.

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