各向异性标准化方差计算重磁源边界

Calculation of gravity and magnetic source boundary based on anisotropy normalized variance

在重磁源边界定位方法中,传统的梯度方法易受干扰的影响使计算的边界混乱,而且在弱异常处由于叠加异常的影响很难识别场源边界.本文首先利用坐标旋转构造了各向异性高斯函数,提出了各向异性标准化方差计算重磁源边界的方法.理论分析与模型实验详细阐明了该方法的数学含义,并通过干扰分析验证了方法的稳定性与有效性,结合中扬子地区航磁异常处理实例,表明通过计算各向异性标准化方差,可以有效地确定重磁源边界,尤其对微弱异常能够实现较好的边界定位,计算的边界分辨率高且信息丰富,有利于资料的综合解释.

For the calculation of gravity and magnetic source boundary, the traditional gradient methods are vulnerable to disturbance and the resulting edges may be too cluttered when the field data are affected by noise. Besides, for the weak anomaly, sources tend to interfere with one another and consequently the edges of geological bodies may be impossible to detect. In this paper, we first construct anisotropic Gauss function based on coordinate rotation, then we propose the formula of calculating anisotropy normalized variance to detect source edge, and clarify its geological significance through theoretical analysis. The numerical experiment shows the method is stable and effective. Applications on both synthetic data and aeromagnetic data in mid Yangtze region indicate that anisotropy normalized variance can effectively determine the gravity and magnetic source boundaries, it also can get good results especially for weak anomaly, the results contain high-resolution and rich information, and these will facilitate the integrated interpretation.