The impedance tensor and tipper are shown to be non-causal in some classes of 2-D and 3-D magnetotelluric (MT) models, including those widely encountered off shore. At the same time, examination of a large database of onshore MT records yields only a handful of non-causal tensors, being non-causal due to the influence of nearby artificial conductors rather than some exotic geological conditions. This result implies that the actual chance to encounter a non-causal impedance tensor or tipper in terrestrial MT exploration is vanishingly small, thus securing the universal applicability of the dispersion relation technique for quality assessment of the mentioned transfer functions.

中文翻译：

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大地电磁色散关系的有效性。第二部分：综合和现场数据

在某些类别的 2-D 和 3-D 大地电磁 (MT) 模型中，阻抗张量和倾卸器显示为非因果关系，包括那些在海上广泛遇到的模型。与此同时，对陆上 MT 记录的大型数据库的检查只产生了少数非因果张量，由于附近人工导体的影响而不是一些奇异的地质条件，这些张量是非因果的。该结果意味着在陆地 MT 勘探中遇到非因果阻抗张量或倾角的实际机会微乎其微，从而确保色散关系技术对上述传递函数的质量评估的普遍适用性。