3-D inversion of the regional magnetic data in spherical coordinates and its preliminary application in Australia

Abstract

To properly construct broad features of lithospheric magnetization structure derived through inversion of the regional magnetic anomaly data, the curvature of the Earth should be taken into consideration. A method for inverting large-scale magnetic anomaly data in spherical coordinates has been developed. The recovered model is in the form of a 3D spherical orthogonal mesh. The inversion uses a classical Tikhonov regularization approach by incorporating a specially formed model objective function in spherical coordinates. We illustrate the algorithm using a synthetic example and then apply it to the satellite magnetic data over Australia. The results from the synthetic data example show that the inversion method in spherical coordinates is able to recover large-scale magnetization distributions. The inverted model in the field example is consistent with independent geological, heat flow, and Curie depth features published in the literature.