改进的局部波数法及其在磁场数据解释中的应用

局部波数法是一种进行磁场数据解释的常用方法。现有的局部波数法在进行反演时往往需要计算局部波数的导数,会明显地增大噪声的干扰,为解释结果带来误差。提出3种利用磁异常在不同位置或不同高度上局部波数的简单组合来进行场源体深度及构造指数的计算方法,不需要计算局部波数的导数,降低了噪声的干扰,增强了反演结果的稳定性。通过理论模型试验,证明改过的局部波数法在有无噪声的情况下均能很好地完成异常的反演,其反演结果与理论值之间的差距小于理论值的5%。将其应用于四川某地区磁异常的反演中,其结果与解析信号的欧拉反褶积法的反演结果吻合。

Improved Local Wavenumber Methods in the Interpretation of Magnetic Fields

Local wavenumber method is a widely used method in the interpretation of magnetic fields,the previous local wavenumber methods need to compute the derivatives of local wavenumber in the inversion,which increase the effect of noise obviously,and bring the errors to inversion results.The authors proposed using the simple combinations of different locations and heights of local wavenumber of magnetic anomaly to compute the depth and structural index of the causative source,and these methods do not need to compute the derivatives of the local wavenumber,which reduce the effect of the noise,and increase the stability of the inversion results.The new methods are demonstrated on theoretical magnetic field data without and with random noise,and the difference between the inversion results and theoretical values is less than 5% of the theoretical values.The practical application of the new methods is tested on real magnetic anomaly from Sichuan basin,Southwest China,the inversion results are consistent with the results computed by the Euler deconvolution of analytic signal.The proposed local wavenumber methods can finish the inversion of magnetic data effectively.