Forward modeling and inversion of variable density interface in spherical coordinate system

The inversion method of density interface can infer the undulation morphology of tectonic interface, which is of great significance to the analysis of regional geological structure, deep earth structure, and the division of tectonic units. In terms of large regional or global scale scenarios, the interface inversion method constructed in a spherical coordinate system provides relatively small approximation errors. In this paper, we develop an approach of variable density interface inversion in spherical coordinate system for the ground observation data. We theoretically derive and improve the Gauss Legendre integration algorithm to propose a forward modeling method for variable density interfaces in a spherical coordinate system. Furthermore, a density interface inversion based on an iterative optimization algorithm in spherical coordinate system is developed. The proposed method shows competitive performance on synthetic data examples, indicating the application potential of characterizing interfaces through large-area ground observation data.