Estimating the macroanisotropy of a horizontally layered section from controlled-source radiomagnetotelluric soundings

Shlykov, A.; Saraev, A.

doi:10.1134/s1069351315040102

Cited by 10 publications

(9 citation statements)

References 18 publications

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“…However, these conditions were pathological in the sense that the quasi-stationary regime is not valid anymore, and the displacement currents must be considered. The only reason such computations make sense is the quasi-stationary impedance was similar to the displacement-current one, at least in the 1D Earth, as demonstrated by [13].…”

Section: Discussionmentioning

confidence: 88%

“…in the Earth. The computations were performed by the 1D code of [13]. Computed curves are presented in Figure 2.…”

Section: Applicability Of Quasi-statinary Simulationmentioning

confidence: 99%

“…We used 18 frequencies with range from 192 Hz to 550 kHz. It should be emphasized that the electromagnetic field above 25 kHz was not quasi-stationary for our setup, but impedance computed from individual components still can be used to interpret the real measurements (see [13]). Two transmitter lines were used to compute the two polarizations.…”

Section: Numerical Simulation Of Aleksadrovkamentioning

confidence: 99%

“…The biggest difference with CSAMT is the displacement currents in the air [10,12] cannot be neglected to accurately compute the electric and magnetic fields, which complicates the numerical simulation dramatically. The authors of [13] demonstrated, however, that the full impedance and quasi-stationary impedances are almost identical in the 1D Earth. It suggests that the CSRMT measurements can be interpreted using an inversion software with the quasi-stationary forward simulation engine (note, though, [14,15]).…”

Section: Introductionmentioning

confidence: 99%

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Parallel Simulation of Audio- and Radio-Magnetotelluric Data

Yavich

Malovichko

Shlykov³

2019

Minerals

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This paper presents a novel numerical method for simulation controlled-source audio-magnetotellurics (CSAMT) and radio-magnetotellurics (CSRMT) data. These methods are widely used in mineral exploration. Interpretation of the CSAMT and CSRMT data collected over an area with the complex geology requires application of effective methods of numerical modeling capable to represent the geoelectrical model of a deposit well. In this paper, we considered an approach to 3D electromagnetic (EM) modeling based on new types of preconditioned iterative solvers for finite-difference (FD) EM simulation. The first preconditioner used fast direct inversion of the layered Earth FD matrix (Green’s function preconditioner). The other combined the first with a contraction operator transformation. To illustrate the effectiveness of the developed numerical modeling methods, a 3D resistivity model of Aleksandrovka study area in Kaluga Region, Russia, was prepared based on drilling data, AMT, and a detailed CSRMT survey. We conducted parallel EM simulation of the full CSRMT survey. Our results indicated that the developed methods can be effectively used for modeling EM responses over a realistic complex geoelectrical model for a controlled source EM survey with hundreds of receiver stations. The contraction-operator preconditioner outperformed the Green’s function preconditioner by factor of 7–10, both with respect to run-time and iteration count, and even more at higher frequencies.

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Section: Discussionmentioning

confidence: 88%

“…in the Earth. The computations were performed by the 1D code of [13]. Computed curves are presented in Figure 2.…”

Section: Applicability Of Quasi-statinary Simulationmentioning

confidence: 99%

Section: Numerical Simulation Of Aleksadrovkamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Parallel Simulation of Audio- and Radio-Magnetotelluric Data

Yavich

Malovichko

Shlykov³

2019

Minerals

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“…They demonstrate the use of a grounded electric dipole as a source, where they could measure the signal in a wide frequency range by utilizing the odd harmonics of the base frequency. Shlykov and Saraev (2015) discuss and present the possibilities of estimating the macro‐anisotropy of the earth material from the RMT sounding and using a controlled source that transmits the signals up to 1000 kHz. They also provide a forward modelling solution that takes into account the displacement currents.…”

Section: Introductionmentioning

confidence: 99%

Radio‐magnetotelluric and controlled‐source magnetotelluric surveys on a frozen lake: Opportunities for urban applications in Nordic countries

Bastani

Wang

Malehmir

et al. 2021

Near Surface Geophysics

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In a novel approach, we have carried out controlled-source and radio-magnetotelluric measurements in the frequency range of 2-250 kHz on a frozen lake located over a planned major multi-lane underground road tunnel near the city of Stockholm. The aim was to gain a better understanding of the resistivity variations above and, potentially, within the crystalline bedrock. Previous studies on the lake water using the boat-towed radio-magnetotelluric technique at the higher end of the frequency band lacked resolution at depth and could not provide conclusive information about bedrock level and potential fracture systems within the bedrock. Taking advantage of Nordic winters, we measured four profiles on the frozen lake complementing the previously acquired boat-towed radio-magnetotelluric data utilizing a double horizontal magnetic dipole transmitter that generated signals down to 1 kHz. The new resistivity models, incorporating the lower frequency data, show improvements and deeper penetrations based on a combined analysis of penetration depth, data misfits and sensitivity studies. The resistivity models also show better correlation with the available high-resolution shallow water seismic reflection data and the geological observations. A potential fracture system within the bedrock can also be inferred better in the new models. The idea of running similar surveys on frozen lakes can be further exploited in similar conditions in countries such as Sweden, where approximately 7% of the land is covered by freshwater bodies and poorly explored for infrastructure planning projects.

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