Improved Gravity-Geologic Method and Its Application to Seafloor Topography Inversion in the South China Sea

  Objectives  The accuracy of the traditional gravity-geologic method (GGM) for inversion of seafloor topography should be improved.

  Methods  This paper proposes an improved GGM (iGGM) consi-dering the nonlinear term.The 1 arc minute seafloor topography of the South China Sea is inverted by iGGM, and its accuracy is evaluated through check points to verify the effectiveness.

  Results  The results show that neglecting nonlinear term of seafloor topography results in a deviation of approximately 50 mGal in mountainous areas with undulation of approximately 2 km. The nonlinear term of seafloor topography could be recovered by the iGGM from short-wavelength gravity anomaly.

  Conclusions  Compared with the traditional GGM, ETPO1 and SIO V23.1, iGGM has the best accuracy. The root mean square of deviations between iGGM and check points is 130.4 m. Compared with traditional GGM, the improvement of iGGM is 10.8 m near the Huangyan seamount chain, and it is 4.7 m near the Zhongsha Islands.