中心回线瞬变电磁探测的一种快速解释方法

分析了中心回线装置激发的电磁场在晚期与平面电磁波的传播特征,通过时-频转换将TEM数据转换成平面波场数据,构建了关于反射函数的M×N阶欠定方程组。用线性规划法解出反射函数序列q_m,大量模型的反演结果与理论值误差很小。以q_m为参数绘制出电磁响应时间剖面图,从而实现了TEM快速成像解释。成像剖面清楚地反映了断面的地电特征。实测资料的处理结果说明了方法的实用性。

A NEW RAPID INTERPRETATION METHOD FOR CENTRAL-LOOP-SOURCE TRANSIENT ELECTROMAGNETIC DETECTION

The central-loop device is an important surveying means for transient electromagneticmethod. It is necessary to make a rapid interpretation and improve the interpretation level. The electromagnetic field stimulated by the central-loop-source in the late period is similar to the plane-electromagnetic-wave. Through the time-frequency conversion, the TEM data are transformed to the plane-wave field data, thus constructing the system of M×N order underdetermined equations related to the reflection function. The authors have designed a computer programme to solve the reflected function sequence q_m with the method of Linear programming, and the error between the inversion result of a host of models and the theoretical value is very small, which indicates this method is feasible and the calculation result is correct. The electromagnetic response time-section is drawn with the parameter q_m, which realizes the explanation of the TEM rapid imaging. The imaging section clearly reflects the geoelectric characteristics of the section. The processing results of the field data demonstrate that this method is useful and practical.