A numerical study of transient electromagnetic sounding effect using the induced voltage and the B field data
LI Zhan-Hui1(), YANG Miao-Xin2, CAO Xue-Feng1
1. China Aero Geophysical Survey and Remote Sensing Center for Natural Resources, Beijing 100083, China 2. Hebei Key Laboratory of Strategic Critical Mineral Resources, Hebei GEO University, Shijiazhuang 050031, China
In this study, the authors compared the loop source transient electromagnetic sounding effect between the induced voltage data and Bz data obtained by one-dimensional and three-dimensional forward modelling. The longest effective delay time of the two types of data under the current data acquisition accuracy of mainstream hardware was analyzed through a comparison of multiple models; the longitudinal and horizontal resolutions of the two types of data were analyzed through a comparison of apparent conductivity and one-dimensional inversion. The results show that, under the data acquisition accuracy presumed in this study, only when an abnormal body with a conductivity ≥ 0.036 S/m exists in the model can the effective delay time of the Bz data be longer than the induced voltage data. Compared with the induced voltage data, the Bz data can sense the underground anomaly in advance, but are worse in longitudinal and horizontal resolutions. The recovery of resistivity by Bz data is also worse than that by the induced voltage data. In the actual field measurement, it is not recommended to record only the Bz field. If conditions are allowed, the induced voltage and the Bz field could be collected simultaneously to obtain an optimized solution.
李展辉, 杨淼鑫, 曹学峰. 瞬变电磁法感应电压场与B场探测效果的数值计算对比分析[J]. 物探与化探, 2021, 45(1): 114-126.
LI Zhan-Hui, YANG Miao-Xin, CAO Xue-Feng. A numerical study of transient electromagnetic sounding effect using the induced voltage and the B field data. Geophysical and Geochemical Exploration, 2021, 45(1): 114-126.
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