局部波数反演磁源参数的改进算法及应用

Improved local wavenumber methods for magnetic source parameters and its application

利用局部波数确定磁源体的深度及类型是一种非常有效且实用的方法.本文基于水平方向波数k_x和垂向波数k_x的理论公式,推导出2种求取场源参数的方法.这2种方法均是要首先确定波数k_s的极大值点及其对应的水平坐标,然后利用k_s异常及向上延拓不同高度的k_s异常与该极大值作相应的计算反演场源深度及构造指数.模型试验证明了本文方法可以准确的计算出地质体的埋深及构造指数,与理论值偏差较小,在理论模型异常上加入一定幅值的干扰噪声,依然可以得到较为准确的反演结果.将其应用于一段实测岩脉数据,其结果与实际资料吻合.

Local wavenumber method is a very effective and practical method for estimating the depth and the nature（structural index） of the source.In this paper,we present two new potential-inversion methods based on the theoretical formulas of local wavenumber kx and kz.In the application of these two methods,we need to determine the maximum point of wavenumber ks and the corresponding horizontal coordinate first,and then combine this maxima and ks anomaly and different heights of ks using the corresponding calculation for computing the depth and structural index of the causative source.Noise-free model test proved that these methods can accurately calculate the depth values and the structure index values,with small deviation to the theoretical values.The methods were also tested on the noise-corrupted model,inversion results showing a successful application.The practical utility of the methods is demonstrated using field example over a dike-like body whose source parameters are known from closely drilling information,and the inversion results are in accord with the true values.