Interpretation of magnetic anomalies by horizontal and vertical derivatives of the analytic signal

利用解析信号的水平与垂直导数进行磁异常的解释(英文)

Magnetic anomalies are often disturbed by the magnetization direction, so we can＇t directly use the original magnetic anomaly to estimate the exact location and geometry of the source. The 2D analytic signal is insensitive to magnetization direction. In this paper, we present an automatic method based on the analytic signal horizontal and vertical derivatives to interpret the magnetic anomaly. We derive a linear equation using the analytic signal properties and we obtain the 2D magnetic body location parameters without giving a priori information. Then we compute the source structural index （expressing the geometry） by the estimated location parameters. The proposed method is demonstrated on synthetic magnetic anomalies with noise. For different models, the proposed technique can both successfully estimate the location parameters and the structural index of the sources and is insensitive to noise. Lastly, we apply it to real magnetic anomalies from China and obtain the distribution of unexploited iron ore. The inversion results are consistent with the parameters of known ore bodies.

磁性体受磁化方向的影响往往使异常形态发生畸变,因此不可以直接利用原始异常来估算场源体的深度和类型。二维情况下磁异常的解析信号具有不受磁化方向干扰的特性,本文提出一种基于解析信号水平与垂直导数的自动磁异常解释方法。首先利用解析信号的性质推导出一线性方程,该方程在无任何先验信息的情况下就可以计算出磁性体的位置参数,然后利用获得的位置参数计算场源的构造指数。通过模型产生的磁异常试验本文方法的可行性,结果证明本文方法能成功地计算出不同类型场源体的位置和构造指数,且受噪声干扰较小。最后将本文方法应用于解释实测磁异常,获得了未开采铁矿的分布情况,且与已知矿体的分布形态相一致。