A new method to estimate the total magnetization direction from the magnetic anomaly: Multiple correlation

Natural remanent magnetization diverts the direction of the total magnetization vector from the earth's magnetic field di-rection. It is important to determine the magnetization direc-tion because the processing and inversion of magnetic usually need the magnetization direction as a priori information. The conventional strategy for estimating the magnetization direc-tion is to compute the crosscorrelation between the reduced-to -the-pole (RTP) field and one magnetic magnitude transform, which is insensitive to the magnetization direction. A new theory and method are proposed that the total magnetization direction is determined by computing the multiple correlation coefficients between the RTP field and the multiple direction -insensitive magnitudes transforms, such as the total magnitude anomaly and the normalized source strength. The linear regres-sion between the RTP field and the direction-insensitive mag-nitude transforms is established. Then, the correlation is computed by the RTP field and the constructed regressor. The proposed method is tested on synthetic of single and com-plex models, respectively. Then, the method is applied to the field data of the Yeshan region (eastern China) and the Black Hill Norite (southern Australia). The proposed multiple corre-lation is an extension of the conventional crosscorrelation method that provides an accurate and robust way to estimate the magnetization direction from the total field anomaly.