关于频率电磁测深几个问题的探讨(六)——频率电磁测深的电磁场分布与观测参量

分析了水平电偶源与垂直磁偶源的电磁场在半空间大地中的分布特点，指出观测各场分量的合适地面部位。为了定性解释，一般将场分量计算为单分量视电阻率或比值视电阻率；做定量解释时，可直接采用场强进行反演，以减小换算误差。基于当前电偶源与磁偶源的发射功率和电磁场衰减规律，在实际应用中，水平电偶源可探测更大深度(<3 000 m)，垂直磁偶源探测浅部(<500 m)。 

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).