The electromagnetic field distribution and observation parameters in frequency electromagnetic sounding

This paper analyzed electromagnetic field distribution characteristics of horizontal electric dipole and vertical magnetic dipole in the half space, pointed out the appropriate ground observation of the field components. In order to qualitatively explain, in general the field components are converted into apparent resistivity or ratio apparent resistivity of a single component. During the quantitative interpretation, field strength can be directly used to conduct inversion to reduce the conversion error. Based on current transmission power of electric dipole and magnetic dipole source and attenuation law of the electromagnetic field, in the practical application, horizontal electric dipole source can detect greater depth (< 3 000 m), vertical magnetic dipole source detects shallow earth(< 500 m).