磁梯度张量解析信号分析法及其在场源位置识别中的应用

Analytic signals of magnetic gradient tensor and their application to estimate source location

相对于传统磁异常数据,磁梯度张量数据可以提供有关异常体更多的信息,分辨率更高,具有广阔的应用前景.本文给出了基于磁梯度张量解析信号进行边界增强的新方法,该方法是通过对异常垂向一阶导数与z方向解析信号的比值做归一化得到的,其零值线位置可以很准确的反映出地质体边界位置,而且可以有效降低噪声的干扰.文中还证明了异常垂向一阶导数与x、y、z三个方向解析信号的比值同样满足欧拉齐次方程,且在计算过程中不需考虑构造指数N的影响,避免了因构造指数不当而引起的反演误差.通过对单一地质体及组合地质体模型的实验证明:与常规欧拉反褶积法相比,该反演方法能够更好的得到地质体界面及深度信息,所得的解更集中.将其应用到保定实测数据中,获得了更精确的场源信息.

Magnetic gradient tensor data can provide more information about the anomalies with higher resolution in contrast to the traditional gravity anomaly data, having vast application prospect. In this paper, we present a new edge identification method based on the analytic signal of magnetic gradient tensor,which can be derived by normalization of the ratio of first derivative and analytic signal in z directions. This method can reflect the edge of causative bodies exactly and reduce the noise interference effectively. I also demonstrate in this paper that the ratio of first derivative and analytic signal in x,y,z directions are homogeneous and satisfy Euler ＇s homogeneity equation,thus a linear equation can be acquired. This method allows the estimation of location parameters without any prior information about the nature（ structural index） of the source,avoiding inversion errors that conventional Euler deconvolution method have caused by improper choice of structural index N. The presented method is tested on single and synthetic magnetic anomalies,and the inversion results show that the method can provide the location parameters more accurately compared with conventional Euler deconvolution method. And we obtained more accurate information sources by applying it to the real magnetic data in Baoding area.