Seismoelectric waves generated by a point source in horizontally stratified vertical transversely isotropic porous media

Cheng, Qianli; Gao, Yongxin; Zhou, Guan-Qun; Chen, Chieh‐Hung; Wang, Dongdong; Yao, Cheng

doi:10.1190/geo2022-0386.1

Cited by 4 publications

(3 citation statements)

References 75 publications

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“…The seismic and EM wavefields generated by a point source in a stratified model can be solved using the Global Matrix method (Cheng et al, 2023;Haartsen & Pride, 1997). Here we apply the eigenvalue decomposition operation on the system matrix M for the n-th layer medium…”

Section: Methods and Solutionsmentioning

confidence: 99%

“…The seismic and EM wavefields generated by a point source in a stratified model can be solved using the Global Matrix method (Cheng et al., 2023; Haartsen & Pride, 1997). Here we apply the eigenvalue decomposition operation on the system matrix M for the n ‐th layer medium

{\boldsymbol{M}}_{n}{\boldsymbol{D}}_{n}={\boldsymbol{D}}_{n}{\boldsymbol{\mathit\Lambda }}_{n},

where Λ n and D n are the diagonal matrix of eigenvalues and the matrix of eigenvectors associated with M n .…”

Section: Theoretical Formulationsmentioning

confidence: 99%

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Numerical Simulation of Electromagnetic Responses to an Earthquake Source Due To the Piezoelectric Effect of ‘∞m’ Symmetry

Zhao,

Gao,

Cheng

et al. 2024

JGR Solid Earth

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It is reported that earthquakes are accompanied by electromagnetic (EM) anomalies. These anomalies are thought to be caused by earthquakes but their generation mechanism is still unclear. The piezoelectric effect has been proposed as a possible mechanism, particularly in quartz‐rich rocks. However, the EM responses to earthquakes due to such an effect have not been well understood. In this article, we study the EM signals generated by an earthquake source due to the piezoelectric effect. We develop a semi‐analytical method to simulate the EM responses to earthquake sources in a 3‐D layered model and conduct numerical simulations to investigate the characteristics of the EM fields. The results show that the piezoelectric effect in quartz‐rich rocks could be the responsible mechanism for the EM signals recorded during the earthquake. Two kinds of EM signals can be generated by the earthquake, namely, the early EM wave arriving before the seismic waves and the coseismic EM field accompanying the seismic waves. For an Mw 6.1 earthquake, the coseismic electric field is ∼0.1 μV/m and the magnetic field can only reach ∼10−5 nT. We also study the sensitivity of the coseismic EM fields to the rock conductivity. The results indicate that the coseismic EM fields are mainly affected by the conductivity of the shallow layer where the receiver is located, and if the top layer is thin, they are also affected by the conductivity of the deeper layer due to the contribution of the evanescent EM wave created at the interface.

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Section: Methods and Solutionsmentioning

confidence: 99%

{\boldsymbol{M}}_{n}{\boldsymbol{D}}_{n}={\boldsymbol{D}}_{n}{\boldsymbol{\mathit\Lambda }}_{n},

where Λ n and D n are the diagonal matrix of eigenvalues and the matrix of eigenvectors associated with M n .…”

Section: Theoretical Formulationsmentioning

confidence: 99%

Numerical Simulation of Electromagnetic Responses to an Earthquake Source Due To the Piezoelectric Effect of ‘∞m’ Symmetry

Zhao,

Gao,

Cheng

et al. 2024

JGR Solid Earth

Self Cite

View full text Add to dashboard Cite

show abstract

“…Based on the above theoretical models, a large number of analytical and numerical simulation methods have been proposed. The analytical solutions are for full-space models [4,11,29], or horizontally layered models [5,7,16,30,31]. However, the analytical solutions can only deal with simple models, while numerical simulations are needed when irregular interfaces or lateral heterogeneities are involved.…”

Section: Introductionmentioning

confidence: 99%

Simulation of Seismoelectric Waves Using Time-Domain Finite-Element Method in 2D PSVTM Mode

Yin

Liu

et al. 2023

Remote Sensing

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The study of the numerical simulation of seismoelectric effects is very helpful for understanding the theory and mechanism of seismoelectric activities. Quasi-static approximation is widely used in the numerical simulation of seismoelectric fields. However, numerical errors occur when the model domain is not within the near-field area of EM waves or the medium is of high salinity. To solve this problem, we propose a time-domain finite-element algorithm (FETD) based on the full-wave electromagnetic (EM) equation to simulate seismoelectric waves in 2D PSVTM mode. By decomposing the electrokinetic coupling equations into two independent ones, we can solve the seismoelectric waves separately. In our implementation, we focus our attention on the solution of EM waves based on vector–scalar potentials, while using the open-source code SPECFEM2D to explicitly solve Biot’s equations and obtain the relative fluid–solid displacement, which is taken as the source for the complete Maxwell’s equations. In the solution of EM wave fields, we use an unconditionally stable implicit method for time discretization. Computation efficiency can be improved by combining explicit and implicit recursions. After conducting the mathematical formulation, we first validate our method by comparing its results with the analytic solutions for a half-space and a two-layer model, as well as with a quasi-static approximation method. Moreover, we run numerical simulations and wavefield analyses on an elliptical hydrocarbon reservoir, and reveal that the interface responses are promising for the identification of underground interfaces and hydrocarbon reservoir exploration.

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Modelling of two-dimensional seismic waves in double-porosity media using the frequency-domain finite-element method

Jiang,

Gao,

Wang

et al. 2024

Geophysical Journal International

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SUMMARY We present a frequency-domain finite-element (FDFE) method for simulating PSV-mode seismic waves (including two slow compressional waves) in 2-D double-porosity media. A functional, whose extremum corresponds to the governing equations with boundary conditions for 2-D PSV waves, is constructed. Solving the boundary value problem of the governing equations is thus equivalent to finding the extremum of the associated functional. We use structured rectangular elements to discretize the computational domain and employ perfectly matched layers (PMLs) to absorb the seismic waves. The FDFE method is validated by comparing the results with those from a semi-analytic method. Numerical simulations are conducted to investigate the propagation of seismic waves in double-porosity media. Assuming a non-viscous pore fluid, we simulate the propagation of slow P waves (P2 and P3 waves) in a two-layer model consisting of double-porosity media. We observe the reflection and transmission of the P2 and P3 waves at the interface. Additionally, we simulate the propagation of seismic waves in a model with irregular interfaces. Seismic signals collected from horizontal and vertical receiver arrays have demonstrated that the P1 wave experiences higher attenuation in a double-porosity medium.

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Seismoelectric waves generated by a point source in horizontally stratified vertical transversely isotropic porous media

Cited by 4 publications

References 75 publications

Numerical Simulation of Electromagnetic Responses to an Earthquake Source Due To the Piezoelectric Effect of ‘∞m’ Symmetry

Numerical Simulation of Electromagnetic Responses to an Earthquake Source Due To the Piezoelectric Effect of ‘∞m’ Symmetry

Simulation of Seismoelectric Waves Using Time-Domain Finite-Element Method in 2D PSVTM Mode

Modelling of two-dimensional seismic waves in double-porosity media using the frequency-domain finite-element method

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