Magnetization vector depth from extreme points imaging for magnetic data

ABSTRACT The total magnetization of magnetic sources comprises induced and remanent components. Accurately recovering magnetization vectors is essential for interpreting subsurface rock structures and characterizing remanent magnetization. We develop a new framework for imaging the 3D magnetization vector distribution based on the depth from extreme points (DEXP) imaging technique. The DEXP imaging of the total magnitude anomaly and normalized source strength that are weakly sensitive to the magnetization direction is developed to mitigate the effects of oblique and remanent magnetization, generating images approximating the true source distribution without prior knowledge of the total magnetization direction. Assuming isolated magnetic sources with uniform magnetization further simplifies the vector model, enabling the magnetization vectors to be derived directly from the source images. Distinct from traditional magnetization vector inversion, the morphology of the vector imaging model is governed by the structural index during the imaging process rather than determined through matrix inversion. Implementation of imaging in the frequency domain and incorporation of the sparsity-enforcing focusing function significantly enhance computational efficiency. The approach is validated through applications to the synthetic examples and the aeromagnetic data from the Weilasito region (North China). The resulting vector models provide valuable insights for mineral prospecting, yielding magnetization directions consistent with multiple estimation methods. The DEXP magnetization vector imaging derives magnetic source information from the perspective of potential field imaging, potentially contributing novel insights into the processing and interpretation of magnetization vectors.