Gravity Terrain Effect of the Seafloor Topography in Taiwan

Gravity terrain correction is used to compensate for the gravitational effects of the topography residual to the Bouguer plate. The seafloor topog-raphy off the eastern offshore of Taiwan is extremely rugged, and the depth of the sea bottom could be greater than 5000 m. In order to evaluate the terrain effect caused by the seafloor topography, a modern computer algo-rithm is used to calculate the terrain correction based on the digital eleva-tion model (DEM). Based on the results of this study, the terrain effect caused by the seaf-loor topography makes a significant contribution to the total terrain effect in every region of Taiwan. In the southern coastal area of Taiwan, the ter-rain effect caused by the seafloor topography is approximately six times that caused by land topography. Therefore, the terrain effect caused by the seafloor topography cannot be neglected in the reduction of gravity data measured on land. The terrain correction should be calculated from the DEM of both land topography and bathymetry. The optimum correctio