Separation and Interpretation of Gravity Field Data Based on Two Dimensional Normal Space-Scale Transform (NSST2D) Algorithm: A Case Study of Kauring Airborne Gravity Test Site, Western Australia

摘要

The gravity field signal observed on the surface of the earth is the superposition of the gravitational effects produced mainly by the mass sources at different locations and depths from the surface down to the underground. Reliable geophysical interpretation of gravity anomalies is highly dependent on the validity of the data processing methods and the rationality of the calculated results. This paper proposes a novel potential field separation method based on two-dimensional Normal Space-Scale Transform (NSST2D) algorithm to implement the residual-regional field separation. Compared with the two dimensional Discrete Wavelet Transform (DWT2D) method often appeared in the previous potential field separation studies, the NSST2D algorithm can keep the shape of the separated field from distortion by normalizing the conventional two-dimensional wavelet transform kernels. Based on gravity field of synthetic models, the separated residual-regional fields respectively derived from DWT2D with five different wavelet bases and those from NSST2D are compared. The experimental results verify the effectiveness and superiority of the proposed NSST2D algorithm. Finally, the NSST2D algorithm is also applied to the separation of the complete Bouguer gravity anomaly in the Kauring airborne gravity test site, Western Australia. The results show that the characteristics of the separated field from the corresponding mass sources with different depths maintain relatively good consistency with the feature of the three-dimensional inversion density contrast distribution.