Magnetic Data Profiles Interpretation for Mineralized Buried Structures Identification Applying the Variance Analysis Method

摘要

We have developed a new method for the interpretation of a magnetic anomaly profile by idealized-geometrical bodies using the variance analysis. This method is based on estimating the fourth horizontal derivative of the magnetic data profile. The advantage behind the use of the fourth horizontal derivative method is to reduce the regional background effect. The model parameters estimated are the depth and shape of the buried body using all available window lengths (s-value). Then, the variance value for the calculated depth at each shape value is estimated using all available s-values. The minimum variance is considered as the best criterion for determining the best-inverted parameters (depth and shape). The developed method has been verified on some noise free examples. Following that, the accuracy of the method was assessed by studying the impact of synthetic data with 5%, 10%, and 15% random noise, the effect of the regional background, the influence of interfering structures, and the selection for the wrong origin of the body. The presented method has been successfully applied to three real case studies from Brazil and India from mineral exploration.