Analysis of Multi-component Response Characteristics of Electrical Source Transient Electromagnetic

Electrical source transient electromagnetic (TEM) method has been developed rapidly as the advantages of large detection depth, high efficiency and complex terrain applicability. In recent years, majority research on electrical source TEM focused on dBz/dt and Ex, while less attention paid to other components, which have similar detection capabilities. In this paper, based on the layered model multi-component modelling method, analysed the detection ability of each component and the influence of offset on the low and high resistance layer. Then, based on the time domain vector finite element method, combined with parallel solver and SAI-Krylov subspace technology, developed 3D fast forward algorithm. 3D complex low and high resistance models are simulated, and the resolution of each component to low and high resistance is discussed. The layered and 3D results show that: Ex is negative anomaly for both low and high resistance bodies, and cannot distinguish high and low resistance, dBy/dt has strong detection ability for both low and high resistance anomalous, dBy/dt, dBz/dt and Ex are easy to cause false anomalies, all components would cause detection blind area with the increase of offset. In face of complex detection environments and different detection targets, these understandings are helpful to optimize the field design scheme, improve the accuracy of data processing and resolution.