基于重力异常的松辽盆地构造特征识别

为了解决构造识别中多个断层不能同时识别倾向的问题，提出了利用断裂构造重力异常水平导数的分布特征实现的倾向成像技术，即断裂水平导数变化率较小的一侧指示断裂的倾向；由此可直接标识出断裂的特征，避免了以往该类方法复杂的运算。将这种技术应用到松辽盆地的实测重力异常的处理中，获得了松辽盆地的构造特征。松辽盆地东西两侧具有明显的重力异常差异，但已有的电法、地震资料难以揭示这种差异的原因。笔者以地震数据为约束，利用重力数据进行松辽盆地地层界面的反演，获得了莫霍面及以下的界面特征；认为松辽盆地重力异常差异的原因是松辽盆地莫霍面下方10 km存在一个界面，且由于太平洋板块的俯冲造成该界面在松辽盆地发生了较大的起伏，从而呈现异常的变化。

Structure Identification by Gravity Anomaly in Songliao Basin

The authors deduced that the distribution of the horizontal derivative of the gravity anomaly of the fault structure can realize the recognition of the fault tendency,which indicates the tendency of the fracture on the side of the small change rate of the fracture horizontal derivative,so it can directly identify the fracture characteristics and avoid the complicated operation of the previous methods.The technique is applied to the treatment of gravity anomaly in Songliao basin,and the tectonic characteristics of Songliao basin are obtained.There are obvious differences of gravity anomaly between the east and the west of Songliao basin,and the reasons of the difference are difficult to be revealed by electric method and seismic data.The boundary inversion of Songliao basin is conducted by gravity data,and the interface features of Moho surface and below are obtained by using seismic data.It is proved that the difference of gravity anomalies in Songliao basin is caused by the boundary of 10km under Moho in Songliao basin,and the great fluctuation occurs in Songliao basin due to the subduction of the Pacific plate.