Electromagnetic Geotomography – Frequency Selection

Andrzej Prałat and Rafał Zdunek

Institute of Telecommunications and Acoustics, Wrocław University of Technology, Wyspiańskiego 27, 50-370 Wrocław, Poland, Email: andrzej.pralat@pwr.wroc.pl

ABSTRACT

The influence of frequency on the accuracy of electromagnetic field distribution measurements needed for image reconstruction is examined. Various factors having a bearing on the choice of the optimum frequency are considered for a frequency range of 0.1-20 MHz which is practicable for geotomography. Most of the evidence indicates that the possibly highest frequencies should be used, but this entails an increase in the attenuation coefficient. The increase is not synonymous with a commensurate reduction in the maximum distance from the electromagnetic field source, over which measurements can be made.

Keywords Electromagnetic geotomography, electromagnetic fields in the ground, attenuation coefficient, dipole field in the ground