EFFECT OF GEOID UNDULATION ON INVERSION OF DENSITY
STRUCTURES OF THE EARTH
1)National Earthquake Infrastructure Service，Beijing 100045
2)State Key Laboratory of Geodesy and Earth’s Dynamics，IGGCAS，Wuhan 430077
3)Key Laboratory of the Earth’s Deep Interior Chinese Academy of Science，Beijing 100026
Abstract：Difference between geoid and reference ellipsoid called geoid undulation.Bouguer gravity anomalies are widely used in density inversion，however，the effects of geoid undulation on gravity were not considered in traditional gravity corrections during the calculation of bouguer gravity.Effects of geoid undulation on gravity were calculated，and bouguer gravity anomalies under consideration of the effects were obtained，as well as，the gravity effects and its relative ratios to bouguer anomalies were analyzed.The results indicate that both of them is coherent with terrain distributions，the largest effects of geoid undulation on gravity locate in basins while the largest relative ratios locate in the third terrain ladder of China mainland.It is suggested that the gravity effects of geoid undulation should be considered when bouguer gravity anomalies were used to invert and interpret density structures，especially in the third terrain ladder of China mainland and basin areas.
