大地电磁概率成像的一种改进方法

An Improvement of Magnetotelluric Probability Tomography

大地电磁概率成像方法可以对地质异常体进行成像。但是对于TE模式,在低频时其成像效果较差。对比提出改进措施,新方法的成像对象不是图像本身,而是图像的边缘。对测量的磁场分布取x方向的导数、而不改变磁场扫描函数,概率成像函数是以上两函数经归一化后的互相关系数,可以实现对边界的成像。改进前、后的水平棱柱体模型和断层模型的概率成像的对比图表明,新方法的高概率值集中于图像的边缘附近,对于图像的判断非常有利。

Magnetotelluric probability tomography can be used to recognize the most probable localization of the geological anomalies. It is not good in low frequencies for TE mode. Retrieved picture of proposed improvement is the edge distributing of the image than the image itself. In the new method, taking the derivative of the measured magnetic field distribution along the x-axis, without changing the scanning function, corresponding occurrence probability function is defined as the crosscorrelation product of the above two functions, divided by the square root of the product of the respective variances. Inversion picture from new probability function is better to recognize the most probable localization of the geoloigical anomalies interface. Contrasting figures of synthetic prism model and the fault model, high probability value of new method, concentrated on the vicinity of the edge of the image, are favor to make a right conclusion and show the improvement is practicable.