Time-lapse seismic tomography of an underground mining zone

Wang, Zewei; Li, Xibing; Zhao, Dapeng; Shang, Xueyi; Dong, Longjun

doi:10.1016/j.ijrmms.2018.04.038

Cited by 34 publications

(26 citation statements)

References 73 publications

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“…Contrary to the expectations, the model resolved the cavity as a high‐velocity zone instead of a low‐velocity anomaly. This could be attributed to insufficient wave path coverage (mainly for refraction arrivals) across the mine, or possibly by the concentration of local stresses (Wang et al ., 2018). As a result, many of the first breaks ‐ possibly due to diffraction at the cavity ‐ may not have been correctly modelled, as indicated by the ray paths in Fig.…”

Section: Data Acquisition Analyses and Resultsmentioning

confidence: 99%

Exploring a near‐surface subsidence over a rehabilitated underground mine through ambient seismic noise tomography in combination with other geophysical methods

Cárdenas‐Soto

Escobedo‐Zenil

Tejero‐Andrade

et al. 2020

Near Surface Geophysics

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An unexpected surface subsidence in Mexico City on 19 May 2015 prompted a detailed geophysical investigation of the three‐dimensional structure of a collapsed‐soil mine located in a section of the Chapultepec Park in the vicinity of an artificial lake. As revealed from past geological explorations, the subsoil at the site consists of volcano‐sedimentary materials that were quarried in the mid‐20th century; subsequently, during the construction of the park, most of those mines had been only partially rehabilitated, with a potential risk of land subsidence. Near‐surface imaging techniques based on ambient seismic noise as well as microgravimetry, electrical resistivity tomography, shallow seismic refraction methods were evaluated for their applicability to characterize the structure of the collapsed mine. Tomography images computed using ambient‐noise array data characterized the extent of the underground mine showing high‐velocity anomaly, while results from microgravimetry and electrical resistivity tomography analyses indicated the structure through weak contrasts in gravity and resistivity anomalies. Additionally, electrical resistivity tomography results also illustrated the saturated nature of the subsoil. While different methods exhibit different capabilities to constrain such a small spatial feature, the present study highlighted the scope of an integrated approach in confirming the existence of potential voids as well as to estimate soil‐subsidence hazard. In terms of operational convenience and rapid performance, the ambient noise tomography method proved to be a relatively efficient and economical reconnaissance tool for identifying 3D velocity contrasts in an urban environment.

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Section: Data Acquisition Analyses and Resultsmentioning

confidence: 99%

Exploring a near‐surface subsidence over a rehabilitated underground mine through ambient seismic noise tomography in combination with other geophysical methods

Cárdenas‐Soto

Escobedo‐Zenil

Tejero‐Andrade

et al. 2020

Near Surface Geophysics

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“…The location results in this study are similar to those obtained by the 3D Gaussian beam-based method, proving that the location method considering finite-frequency effects of wave propagation is significantly superior to the geometric ray tracing-based location. According to Wang et al [50] and Virieux and Operto [51], the velocity model used in this paper has a resolution of about 50 m. In addition, the Gaussian beam-based method approximately solves the wave equations in a local region around the ray path, thus, partial ray tracing operation is still needed. The modeling accuracy of the Gaussian beam method is lower than that of numerically solving the complete wave equation.…”

Section: Ms Location Resultsmentioning

confidence: 99%

“…To test the proposed 3D GSWI location method, the 3D velocity model inverted through ray tracing tomography based on P wave travel-time data by Wang et al [50] and shown in Section 4.1 was selected as the target velocity model. Moreover, velocity models with different smoothing scales were used to verify the importance of velocity model accuracy to the 3D GSWI location method.…”

Section: Synthetic Testmentioning

confidence: 99%

High-Accuracy Location of Microseismic Events in a Strong Inhomogeneous Mining Environment by Optimized Global Full Waveform Inversion

et al. 2020

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High-accuracy determination of a microseismic (MS) location is the core task in MS monitoring. In this study, a 3D multi-scale grid Green’s function database, depending on recording wavefield frequency band for the target mining area, is pre-generated based on the reciprocity theorem and 3D spectral element method (SEM). Then, a multi-scale global grid search strategy is performed based on this pre-stored Green’s function database, which can be effectively and hierarchically processed by searching for the spatial location. Numerical wavefield modeling by SEM effectively overcomes difficulties in traditional and simplified ray tracing modeling, such as difficult wavefield amplitude and multi-path modeling in 3D focusing and defusing velocity regions. In addition, as a key step for broadband waveform simulation, the source-time function estimated from a new data-driven singular value decomposition averaged fractional derivative based wavelet function (DD-SVD-FD wavelet) was proposed to generate high-precision synthetic waveforms for better fitting observed broadband waveform than those by simple and traditional source-time function. Combining these sophisticated processing procedures, a new robust grid search and waveform inversion-based location (GSWI location) approach is integrated. In the synthetic test, we discuss and demonstrate the importance of 3D velocity model accuracy to waveform inversion-based location results for a practical MS monitoring configuration. Furthermore, the average location error of the 3D GSWI location for eight real blasting events is only 15.0 m, which is smaller than error from 3D ray tracing-based location (26.2 m) under the same velocity model. These synthetic and field application investigations prove the crucial role of 3D velocity model, finite-frequency travel-time sensitivity kernel characteristics and accurate numerical 3D broadband wavefield modeling for successful MS location in a strong heterogeneous velocity model that are induced by the presence of ore body, host rocks, complex tunnels, and large excavations.

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“…Other studies applied collaborative localization methods using analytical and iterative solutions for microseismic sources in underground mining. These studies filtered the abnormal arrivals using analytical solutions combined with the iterative method without premeasured average velocity to improve the location accuracy (Wang et al 2018;Dong et al 2019). These studies emphasized constructing the velocity discontinuities, including Conrad and Moho discontinuities.…”

Section: Methodsmentioning

confidence: 99%

Passive Seismic Imaging of Stress Evolution with Mining-Induced Seismicity at Hard-Rock Deep Mines

Westman

Counter

et al. 2020

Rock Mech Rock Eng

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This work aims to examine the stress redistribution with evolving seismicity rates using a passive seismic tomographic tool. We compiled a total of 26,000 events from two underground mines and partitioned them into multiple clusters in a temporal sequence, each of which contains 1000 events. To image stress redistribution associated with seismicity rates, we then run the tomographic studies using each cluster to yield seismic tomograms and computed the corresponding seismicity rate. We found that high velocity anomalies grew with the increase of seismicity rates, and they switched to a shrinking tendency under low seismicity rates. Results of this study imply that seismicity rates increase with increasing stress concentration and decrease with decreasing stress concentration. This study highlights the value of utilizing passive seismic tomography for estimating stress evolution associated with the change of seismicity rates at underground mines. Our findings illuminate the applications of using mining-induced seismicity to assess stress redistribution associated with seismicity rates at hard-rock mines, providing insights into seismic hazards for deep mining.

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Time-lapse seismic tomography of an underground mining zone

Cited by 34 publications

References 73 publications

Exploring a near‐surface subsidence over a rehabilitated underground mine through ambient seismic noise tomography in combination with other geophysical methods

Exploring a near‐surface subsidence over a rehabilitated underground mine through ambient seismic noise tomography in combination with other geophysical methods

High-Accuracy Location of Microseismic Events in a Strong Inhomogeneous Mining Environment by Optimized Global Full Waveform Inversion

Passive Seismic Imaging of Stress Evolution with Mining-Induced Seismicity at Hard-Rock Deep Mines

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