Vector transformation and reduction to the pole for regional magnetic data with variable field direction

适用于变化磁倾角的区域磁异常三分量转换与化极方法

The vector transformation and pole reduction from the total-field anomaly are signifi cant for the interpretation.We examined these industry-standard processing procedures in the Fourier domain.We propose a novel iteration algorithm for regional magnetic anomalies transformations to derive the vertical-component data from the total-field measurements with the variation in the core-fi eld direction over the region.Additionally,we use the same algorithm to convert the calculated vertical-component data into the corresponding data at the pole and realize the processing of diff erential reduction to the pole(DRTP).Unlike Arkani-Hamed’s DRTP method,the two types of iterative algorithms have the same forms,and DRTP is realized by implementing this algorithm twice.The synthetic model’s calculation results show that the method has high accuracy,and the fi eld data processing confi rms its practicality.

本文从标量磁异常总可视为矢量磁异常在某方向上的投影这一角度出发,系统回顾了磁异常频率域三分量转换和化极的基本表达式,提出了一种适用于变磁化倾角的区域磁异常三分量转换与化极方法。该方法将化极视为分量转换和磁化方向转换两个过程,通过连续两次应用磁异常垂向分量转换程序实现变倾角化极,区别于Arkani-Hamed的变倾角化极方法,两类迭代计算的表达式具有高度统一的优越性。理论模型计算表明该方法具有较高的磁异常分量转换和化极处理精度,实际资料处理表明该方法具有实用性。