Bouguer gravity anomaly is constantly correlated with terrain in mountainous areas, which is unserviceable to geological interpretation of gravity data. This phenomenon is mainly caused by inaccurate terrain correction density. We ascertain the terrain correction density in mountainous areas based on regression analysis. We obtain the terrain correction density by analyzing the relationship between the free-air gravity anomaly and the elevation, and modify the density according to the relationship between the calculated Bouguer gravity anomaly in each step and the elevation. Based on this, we adjust the terrain correction density of topographic correction successively until we obtain the optimum terrain correction density and the corresponding Bouguer gravity anomaly. We have adopted the proposed method for the terrain correction of the gravity data in the Jiuzongshan mountain and obtained the optimum terrain correction density after 5 iterations, and thus the Bouguer gravity anomaly was calculated. The results of Jiuzhongshan mountain confirmed the correctness of our proposed method.
Zhong H, Zhang H L, Liu H H, et al. The area relevant method for estimating optimal stratigraphic density in gravity terrain correction[J]. Geophysical and Geochemical Exploration, 2013, 37(3):512-516.
Niu Y Y, Guo L H, Shi L, et al. Estimation of near-surface density based on gravity Bayesian analysis and its application in Yunnan area[J]. Chinese Journal of Geophysics, 2019, 62(6):2101-2114.
Martins C M, Barbosa V C F, Silva J B C. Simultaneous 3D depth-to-basement and density-contrast estimates using gravity data and depth control at few points[J]. Geophysics, 2010, 75(3):I21-I28.
Florio G. Mapping the depth to basement by iterative rescaling of gravity or magnetic data[J]. Journal of Geophysical Research: Solid Earth, 2018, 123(10):9101-9120.
Florio G. The estimation of depth to basement under sedimentary basins from gravity data: Review of approaches and the ITRESC method, with an application to the Yucca flat basin (Nevada)[J]. Surveys in Geophysics, 2020, 41:935-961.
Liu S R, Gao P, Geng T, et al. The application of different sources DEM data in media region terrain correction of gravity in high mountain areas[J]. Geophysical and Geochemical Exploration, 2019, 43(5):1111-1118.