瞬变电磁水平分量视电阻率定义

为了将瞬变电磁水平分量转化成电阻率参数，实现瞬变电磁水平分量视电阻率定义，对不同偏移距下大定源回线瞬变电磁场水平分量响应进行了数值计算和分析，得出水平分量具有与中心点垂直分量相似的函数形态和函数性质，据此，水平分量可以用与中心点垂直分量类似的多项式进行拟合，从而得到多项式形式的感应电动势表达式。根据瞬变电磁晚期近似条件，用水平分量的拟合多项式，定义相应的晚期视电阻率表达式，从而实现水平分量响应到地下介质电阻率参数的转化。通过对模型的计算可知，上述方法可行，结果正确；通过对实测数据的解释可知，水平分量不仅具有纵向分辨力，也具有较好的横向分辨率。

Definition of apparent resistivity for horizontal component of transient electromagnetic method

In order to transform the horizontal component of transient electromagnetic field into resistivity parameters and get apparent resistivity definition using transient electromagnetic horizontal component，numerical calculation and analysis were made for the transient electromagnetic horizontal component response excited by the large loop with different offset.The results show that horizontal component and the vertical component at the central point have similar functions，in terms of shape and characters.As a result，the horizontal component was fitted with a polynomial which was similar to the polynomial of vertical component at the central point，and then got the expression of induced electromotive force in the form of polynomial.According to the approximation of transient electromagnetic field during the later period，apparent resistivity with the fitting polynomial of horizontal component was defined，in this way，the transform from horizontal component response to resistivity of the medium was realized.The model calculation prove that this method is feasible，and the result is correct.The interpretation of measured data show that horizontal component not only has longitudinal resolution，but also has preferable lateral resolution.