深部大尺度单一密度界面重力异常迭代反演

AN ITERATIVE METHOD FOR INVERSION OF DEEPLARGE-SCALE SINGLE DENSITY INTERFACE BY USING GRAVITY ANOMALY DATA

对于深部大尺度单一密度界面的重力异常反演,需顾及球形观测面和重力铅垂线变化的影响。为此,本文通过球谐展开,得到重力异常的级数展开式,并推导出积分形式的反演迭代解。该迭代方法要求设法分离出单一密度界面的重力异常,已知界面上、下层的密度差和尽可能多的深度控制点。模型和实例显示其效果良好,可用于莫霍界面、岩石层底界面等深部密度界面重力异常的反演。

Because the effects of the sphericity of the measured surface and varying plumb line of gravity need to be taken into account for the inversion of deep-large-scale single density interface,in this paper,we express the interface gravity anomaly as a series of spherical harmonics,and deduce an iterative inverse solution in an integral form.To apply this method,we must know the interface gravify anomaly,density contrast and some depth data as much as possible.The application of model and practical example shows this method works well.It is very useful to detection of deep-large-scale density interface,such as Mohoroviaaic discontinuity,especially lithospherical lower surface.