By Using Satellite Gravity Field Model Inversion Regional Crustal Density

The gravity anomaly calculated by the gravity field model and the bouguer gravityanomaly can well reflect the underground residual mass distribution of geological. Getting theremaining bouguer gravity anomaly caused by the crust quality of residual distribution bydeducting the plastid gravity on the ground observation point below the surface from the totalof bouguer gravity anomaly. This paper deduce the gravity anomaly expression of variabledensity model combining the the rectangle model and density depth function. According tothe rest of the bouguer gravity anomaly and PSO algorithm inversing the three dimensionalcrustal density of the loess plateau, Fen nutrient-laden basin and north china plain.The main achievement are as follows:1.Using c++compiled the high order time Legendre function and also compiled thegravity anomaly programming according to the satellite gravity field model. Using Fortanlanguage compiled the bouguer correction program.2.On the basis of the variety expressions of homogeneous rectangle to forward gravityanomaly, verifying the consistency of the forward expression. The article deduces the gravityanomaly expression of variable density model combining the the rectangle model and densitydepth function. Using c++language compiled the program of variable density forwardmodel.3.The gravity field inversion theory and PSO algorithm is introduced and the programbased on the variable density cuboid forward model which is used to inverse theThree-dimensional crustal density is compiled. The inverse result proved the feasibility of thePSO algorithm can applied to the nonlinear and the complex geophysical problems.4.The loess plateau Fen nutrient-laden basin and the north China plain’s Bouguer gravityanomaly reflecting crust residual mass distribution is calculated using the GOCE、GRACEsatellite gravity data provide by GFZ and EIGEN₆C gravity field model. Getting threedimensional crustal density according to the rest of the bouguer gravity anomaly and PSOalgorithm. Inversion result shows that the study area’s crustal density is high in northwest and the southeast is low, also the density is decreasing from northwest to southeast direction,forming a good mirror relationship with the rest of the bouguer gravity anomaly distribution.Through compare with the Crust1.0model results found that the inversion result tallies withthe Crust1.0model, proved the feasibility that the variable density cuboid model can inversethree-dimensional crustal density distribution directly.