Extracting magnetic anomalies based on an improved BEMD method: A case study in the Pangxidong Area, South China

In bidimensional empirical mode decomposition, an appropriate stoppage criterion for the sifting process is important. To solve the problem of unstable convergence, a stepwise stop criterion was presented based on the Cauchy-type criterion. In one sifting process, a squared deviation of two successive residual components is first calculated. Then, an absolute value of the difference between two continuous deviations is calculated. The sifting process will stop when the difference value is less than the a priori value. A comparison of correlation coefficients of the final results decomposed from experimental models demonstrated that those intrinsic mode functions obtained by the stepwise stop criterion meet the requirements of orthogonality, and the mode mixing effect among them is depressed effectively. With the help of the proposed criterion, an example is given for extracting magnetic anomalies in the Pangxidong area, Guangdong Province, South China. The residual components of the first and second order of bidimensional intrinsic mode functions revealed a spatial relationship between ore deposits and anomalies.