Further investigations of underground resistivity structures in coastal areas using grounded-source airborne electromagnetics

Ito, Hisatoshi; Mogi, Toru; Jomori, Akira; Yuuki, Youichi; Kiho, Kenzo; Kaieda, Hideshi; Suzuki, Koichi; Tsukuda, Kazuhiro; Allah, Sabry Abd

doi:10.5047/eps.2011.08.003

Cited by 36 publications

(10 citation statements)

References 13 publications

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“…The world's first SAEM detection system, Turair, was introduced in the early 1970s [9], [10]. After 1990s, FlairTEM [6], [11], TerraAIR [12], GREATEM [7], [13], [14] appeared. In the early days of the SAEM method and technology development, closed loops had been used as the transmitting antenna (Fig.…”

Section: Origin Of Saem Systemsmentioning

confidence: 99%

The Development and Applications of the Semi-Airborne Electromagnetic System in China

Xue

Fang

et al. 2019

IEEE Access

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Semi-airborne electromagnetic method (SAEM) is a geophysical electromagnetic detection method which places the transmitting subsystem on the ground and the receiver subsystem on the flight platform. This transceiver configuration has been found to be more efficient than that of the traditional ground electromagnetic methods while it can get much deeper penetration than the traditional airborne electromagnetic methods. Therefore, the SAEM has been widely used in mineral, groundwater, geothermal, and other resources exploration fields. In this paper, we would like to take the most key problems encountered in the SAEM system design and application as the starting point, and then we focus mainly on reviewing the progress of the transmitter, sensor, and receiver technology, as well as data processing, modeling, and imaging methods of the SAEM in China. In particular, the research progress of multi-source SAEMs will be introduced. Beyond that, two prospecting examples with different SAEM systems will be introduced. Finally, we will discuss the future of the SAEM in terms of equipment developing, data processing, modeling and inversion, to promote the research and application in this field to a higher level.

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Section: Origin Of Saem Systemsmentioning

confidence: 99%

The Development and Applications of the Semi-Airborne Electromagnetic System in China

Xue

Fang

et al. 2019

IEEE Access

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“…We applied the inversion approach to GREATEM survey data from Kujukuri coastal plain, central Japan (Ito et al, 2011;Abd Allah et al, 2013). In their studies eleven flight lines spaced 200 m apart were carried out.…”

Section: Inversion Of Greatem Field Datamentioning

confidence: 99%

Three-dimensional Inversion of GREATEM Data: Application to GREATEM survey data from Kujukuri beach, Japan

Allah

Mogi

Fomenko³

et al. 2016

ASEG Extended Abstracts

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SUMMARYStudies have shown that Grounded Electrical-Source Airborne Transient ElectroMagnetics (GREATEM) is a promising method for resistivity structures investigating in coastal areas, in addition to inaccessible areas such as volcanoes, mountains and deep forest cover. To expand the application of the GREATEM system, a three-dimensional (3-D) resistivity model that considers large lateral resistivity variations is required. In this paper, we present a frequency-domain 3-D electromagnetic (EM) inversion approach that can be applied to time domain data from GREATEM. In the frequency-domain approach, TEM data were Fourier-transformed using a smooth-spectrum inversion method, and the recovered frequency response was then inverted. To deal with a huge number of grids and a wide range of frequencies in airborne datasets, a method for approximating sensitivities is introduced for efficient 3-D inversion. Approximate sensitivities are derived by replacing adjoint secondary electric fields with those computed in the previous iteration. These sensitivities can reduce the computation time without significant loss of accuracy. Firstly, we verified both of our forwarding and inversion solutions. We then applied this approach to the GREATEM survey data from Kujukuri beach, central Japan. The inverted results of the field data are well fit with the previous study results at Kujukuri area, suggesting the applicability of this inversion approach for constructing 3D resistivity models from the GREATEM field survey data in the future.

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“…Combining the ground and airborne electromagnetic systems, GREATEM has the advantages of large detection depth, high resolution, wide range, and fast speed. In particular, it has unique superiority in mountains, forest-covered areas, swamps, and other special areas [7,8]. Ji (2013) used an airship as the carrier and the two-dimensional finite difference method to calculate the time-domain GREATEM response with a long wire source [9].…”

Section: Introductionmentioning

confidence: 99%

3D Numerical Modeling of Induced-Polarization Grounded Electrical-Source Airborne Transient Electromagnetic Response Based on the Fictitious Wave Field Methods

Meng

Huang

et al. 2020

Applied Sciences

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The grounded electrical-source airborne transient electromagnetic (GREATEM) system is widely used in mineral exploration. Meanwhile, the induced polarization (IP) effect, which indicates the polarizability of the earth, is often found. In this paper, the Maxwell equations in the frequency domain are transformed into fictitious wave domain, where Maxwell equations are solved by the time domain finite difference method. Then, an integral transformation method is used to convert the calculation results back to the time domain. A three-dimensional (3D) numerical simulation in a polarizable medium is presented. The accuracy of this method is proven by comparing it with the analytical solution and the existing method, and the calculation efficiency is increased five-fold. The simulation results show that the GREATEM system has a higher response amplitude in the conductive region, while IP effects cannot be identified in the conductive area. The GREATEM system has a higher response amplitude in the low-resistance region, but IP effects cannot be identified in the low-resistance area, and the detection of IP effects is more suitable for the high-resistance area. Therefore, it is necessary to improve the detection ability of the GREATEM system in the low-resistance area.

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Further investigations of underground resistivity structures in coastal areas using grounded-source airborne electromagnetics

Cited by 36 publications

References 13 publications

The Development and Applications of the Semi-Airborne Electromagnetic System in China

The Development and Applications of the Semi-Airborne Electromagnetic System in China

Three-dimensional Inversion of GREATEM Data: Application to GREATEM survey data from Kujukuri beach, Japan

3D Numerical Modeling of Induced-Polarization Grounded Electrical-Source Airborne Transient Electromagnetic Response Based on the Fictitious Wave Field Methods

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