频率域航空电磁法视电阻率转换在岩性构造填图中的应用

以固定翼航空电磁系统正演公式为基础,介绍了实虚分量法、幅值飞行高度法等均匀半空间模型下的视电阻率转换方法。将内蒙古某测区实测的高、中、低3个频率的航空电磁数据转换为视电阻率,即Hρs、Mρs、Lρs,并对3个频率的视电阻率填图效果进行了试验对比,最后选用Hρs等值线图进行岩性构造填图,与地质图吻合程度较高。提高了航空视电阻率填图的实际意义和应用,为后期资料解释提供了理论基础。

Apparent Resistivity Conversion Application of FAEM in Lithostructural Mapping

Based on the forward formulae for the fixed-wing electromagnetic system,the IQ method and the amplitude-altitude method are introduced,by the homogeneous half-space model of apparent resistivity conversion.The airborne electromagnetical data in high,middle and low frequency are collected in one area in Inner Mongolia,and are converted into the apparent resistivity,namely Hρs,Mρs,Lρs.After comparing the geological mapping effects among Hρs,Mρs and Lρs,the Hρs contour map is considered as the best one to reflect lithostructural mapping,to improve the practical meaning and application of air apparent resistivity mapping by contrasting with the original geological maps,providing a theoretical basis for the final period data interpretation.