Mapping deeply-buried geothermal faults using microtremor array analysis

Xu, Pingwei; Ling, Suqun; Li, Chuanjin; Du, Juan; Zhang, Dengming; Xu, Xueqiu; Dai, Kangming; Zhang, Zuohong

doi:10.1111/j.1365-246x.2011.05266.x

Cited by 37 publications

(6 citation statements)

References 4 publications

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“…The SPAC method is a data-processing method to obtain a microtremor signal and extract the phase velocity dispersion curve of the Rayleigh wave from the vertical component of the microtremor signal by deploying the observation array [15]. It requires a circular observation array; four microtremor acquisition stations are located in the array (Figure 1), one of which is located at the center of the circle (S1), with the other three (S2, S3, S4) evenly distributed on the circumference of the radius (r), forming an equilateral triangle [16]. Taking S1 (0, 0) and S2 (r, θ), the surface wave signals are u (0, 0, ω, t) and u (r, θ, ω, t).…”

Section: Spacmentioning

confidence: 99%

Application of Microtremor Survey Technology in a Coal Mine Goaf

Wang

Tang

2022

Applied Sciences

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Goafs are one of the main factors that endanger the safety of mining areas, leading to roadway collapse, land subsidence and other problems. Determining how to detect goafs accurately and efficiently is an important issue faced in engineering geophysical exploration research. Microtremor survey technology, used in geophysical exploration, has been developed in recent years. It has the advantages of low cost, flexible construction, low topographic impact and high efficiency. In this paper, microtremor survey technology was applied to the detection of a coal mine goaf. In the known goaf area of the Taiyuan Nanling Coal Mine, a linear observation array was arranged to conduct rolling acquisition, observe the microtremor signal records of the natural field and use the extended spatial autocorrelation method to extract the dispersion curve. Through the inversion of the extracted dispersion curve, the apparent shear wave velocity profile of the underground medium clearly showed the location of the goaf. It was roughly consistent with the goaf data obtained from the mine. The detection results reflect the advantages of micromotion exploration. The goaf of Coal Seam #2 and its affected area appear to be due to an obvious low-speed phenomenon. The boundary of the apparent shear wave velocity profile of micromotion detection was basically consistent with the boundary of the goaf, indicating that micromotion exploration technology has good technical advantages and application prospects in the detection of coal mine goafs. The rolling acquisition method of linear arrays can be used to ensure accurate detection, improve exploration efficiency and save on exploration costs.

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Section: Spacmentioning

confidence: 99%

Application of Microtremor Survey Technology in a Coal Mine Goaf

Wang

Tang

2022

Applied Sciences

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“…We then did the tests with three other kinds of arrays (first column in Fig. 7), which are triangular, circular and spiral arrays (e.g., Xu et al, 2012;Cho et al, 2013;Kennett et al, 2015), to investigate the effect of different geometries. Again, we set the directional wavefield to come from the northeast at an azimuth φ=60°.…”

Section: Wavelength Limitsmentioning

confidence: 99%

“…The spatial autocorrelation (SPAC) method is one of the most efficient ways to retrieve surface waves from ambient seismic noise (Aki, 1957(Aki, , 1965. Recent studies of the SPAC method include an extension of the SPAC method to mixed-component correlations (Haney et al, 2012), a generic theory using three-component data (Cho et al, 2006), applications using different array configurations (Ling and Okada, 1993;Bettig et al, 2001;Ohori et al, 2002;Cho et al, 2004;Chavez-Garcia et al, 2005;Xu et al, 2012), direct inversion of SPAC coefficients (Wathelet, 2005), discussion of the relationships between the SPAC method and the traditional cross-correlation technique (Chávez-García and Luzón, 2005;Yokoi and Margaryan, 2008;Ekström et al, 2009;Tsai and Moschetti, 2010), different ways to calculate SPAC coefficients (Weemstra et al, 2013;Weemstra et al, 2014), multimode inversion of surface waves (Ikeda et al, 2012), and extraction of attenuation coefficients (Prieto et al, 2009;Lawrence and Prieto, 2011;Tsai, 2011;Nakahara, 2012;Lawrence et al, 2013;Weemstra et al, 2013;Menon et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

On the reliability and limitations of the SPAC method with a directional wavefield

Luo

Zhu

et al. 2016

Journal of Applied Geophysics

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The spatial autocorrelation (SPAC) method is one of the most efficient ways to extract phase velocities of surface waves from ambient seismic noise. Most studies apply the method based on the assumption that the wavefield of ambient noise is diffuse. However, the actual distribution of sources is neither diffuse nor stationary. In this study, we examined the reliability and limitations of the SPAC method with a directional wavefield. We calculated the SPAC coefficients and phase velocities from a directional wavefield for a four-layer model and characterized the limitations of the SPAC. We then applied the SPAC method to real data in Karamay, China. Our results show that, 1) the SPAC method can accurately measure surface wave phase velocities from a square array with a directional wavefield down to a wavelength of twice the shortest interstation distance; and 2) phase velocities obtained from real data by the SPAC method are stable and reliable, which demonstrates that this method can be applied to measure phase velocities in a square array with a directional wavefield.

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“…The dispersion curve is then inverted to obtain the S-wave velocity structure of the subsurface media, which serves the exploration objective [ 1 ]. The detection of buried faults [ 4 , 5 , 6 ], underground boulders [ 7 ], the soil–rock interface [ 8 , 9 , 10 ], goaf [ 11 ], and landslide mass structures [ 12 , 13 ] are a few of the engineering issues that have been successfully solved using the microtremor survey method in recent years.…”

Section: Introductionmentioning

confidence: 99%

Frequency-Bessel Transform Based Microtremor Survey Method and Its Engineering Application

You

Qian

et al. 2022

IJERPH

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The development and utilization of urban underground space depend heavily on an understanding of urban geological conditions. The microtremor survey method is essential in urban geological surveys due to its quickness, convenience, non-destructiveness, and interference resistance. Since only the fundamental dispersion curves of Rayleigh waves can be obtained by utilizing the spatial autocorrelation method, the inversion results have multiple solutions. To improve the accuracy of the microtremor survey, this study employed the frequency-Bessel transform to extract the fundamental and higher modes of dispersion information of Rayleigh waves from the microtremor data array and verified the effectiveness of this method by synthesizing theoretical microtremor signals. Additionally, taking into account the order identification challenges brought on by mode jumps or missing modes in the dispersion curve, this study processed a multi-mode dispersion curve based on the newly proposed inversion objective function coupled with a genetic algorithm to obtain a shallow surface S-wave velocity structure. Compared to the traditional inversion objective function, the new function presented in this study could address mode misidentification more effectively and improved the accuracy of inversion calculations. Finally, the applicability and dependability of the frequency-Bessel-transform-based microtremor survey method were evaluated in a practical engineering case.

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Mapping deeply-buried geothermal faults using microtremor array analysis

Cited by 37 publications

References 4 publications

Application of Microtremor Survey Technology in a Coal Mine Goaf

Application of Microtremor Survey Technology in a Coal Mine Goaf

On the reliability and limitations of the SPAC method with a directional wavefield

Frequency-Bessel Transform Based Microtremor Survey Method and Its Engineering Application

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