Inversion of gravity and topography data for the crust thickness of China and its adjacent region

摘要

The data of Bouguer gravity and topography are inverted to obtain the crust thickness of China. In order to reduce the effect of regional non-isostasy we corrected the reference Moho depth in the inversion with regional topography relief, and performed multiple iterations to make the result more reliable. The obtained crust thickness of China is plotted on a map in cells of 1°×1°. Then we analyzed the correlation between the Bouguer gravity anomaly and fluctuation of the Moho depth. A good linear correlation is found, with a correlation coefficient of -0.993.Different correlation coefficients, 0.96 and 0.91, are found for the data in land and ocean region, respectively. The correlation result also shows that the boundary between land and ocean is generally along the bathymetric line of -800 m. In order to examine the influence of the Earth's curvature on the calculated result, we tried two inversion models: the inversion for the whole region and the inversion for 4 sub-regions. The difference in the crust thickness deduced from the two models is less than 5 km. Possible explanation for the difference is discussed. After comparing our result with that of other studies, we suggest that with our method the Bouguer gravity and the topography data can be independently inverted to obtain the crust thickness of China and its adjacency.