利用重力数据反演区域地壳密度

Inversion of three-dimensional crustal density structure by using satellite gravity data

基于引力位理论结合均质长方体模型和密度-深度函数关系推导了变密度长方体模型正演重力异常表达式。利用高阶次的卫星重力场模型计算了汾渭盆地及周边地区由地壳密度分布不均引起的剩余布格重力异常,根据该剩余布格重力异常反演得到了该地区三维地壳密度分布。反演结果显示该区域地壳密度具有西北高、东南低且自西北向东南方向递减的特征,并和剩余布格重力异常分布形成良好的镜像关系;反演结果与Crust 1.0模型提供的结果较为吻合,证明了变密度长方体模型直接反演三维地壳密度分布是可行的。

Based on the gravitational potential theory and combined with the function of density with depth in earth crust-mantle,the forward cuboid gravity anomaly expression is derived. The Fen nutrient-laden basin's remaining bouguer gravity anomaly is calculated by using the higher order satellite gravity model,which is caused by uneven crustal density distribution. The three-dimensional crustal density distribution of the region is obtained by inversion of the remaining bouguer gravity anomaly. Inversion result shows that the study area's crustal density is high in northwest and low in southeast,decreasing from northwest to southeast direction,forming a good mirror relationship with the remaining bouguer gravity anomaly distribution. Through comparison with the Crust1. 0 model,we find that the inversion result agrees good,proves the feasibility that the variable density cuboid model can be applied to inverse three-dimensional crustal density distribution directly.