New Art for Crosshole Electromagnetic Tomography

Cao Junxing 1), Nie Zaiping 2) and Zhu Jieshou 1)

1) Chengdu University of Technology, Chengdu 610059, China. e-mail: cjx@cdit.edu.cn
2) University of Electronic Science and Technology of China, Chengdu 610054, China.

Abstract

Crosshole Electromagnetic Tomography(CEMT) is a powerful geophysical exploration technique. It has found many successful applications in engineering and environmental geology detection and mine resources exploration. This paper proposes two new ray EM tomography strategies, one is named Average Multi-Frequency Absorption Tomography (AMFAT) and another Dual-Frequency Conductivity Tomography (DFCT). In AMFAT, the absorption tomography is done using averaged data of different frequencies. The averaged data should be that measured at same configuration. In DFCT, the conductivity tomography is done using the following equation

(Equation)

where E1 , E2 are electric field intensities( unit: dB) measured in far field at same geometry configuration, f1,f2 are frequencies, sigma is the conductivity of the media detected.

Both DFCT and AMFAT can eliminate in some degree the error rising from the approximation of the of an electric dipole antenna by that of a half wave-length dipole antenna. The DFCT is suitable for the medium with high conductivity and the AMFAT the one with low conductivity.

The original abstract contains mathematical expressions that can not be transformed into HTML.


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Last modified: Tue Oct 6 09:55:44 1998