东北地区地壳密度模型反演

摘要

Based on the Moho depth obtained from the two Geoscience Transects which are Manzhouli-Suifenhe and East Ujimqin Qi, Inner Mongolia-Donggou, Liaoning, as well as the depth calculated from the seismic stations using the receiver function,given the searching range of the parameters and appropriate initial temperature etc., we inverse the exponential density model of the crustal structure in Northeastern China by using the simulated annealing algorithms controlled by the fourth-order approximation of the gravity anomaly which can be regarded as a reflection of the undulating interface of Moho. This anomaly is obtained by the multi-scaled wavelet decomposition method. The density contrast between crustal surface and mantle is about-0.9g·cm-3 and the attenuated coefficient is 0.02. We can see that the inversed density model can reveal the variation of vertical density crustal of very well after comparing with the crustal density structures derived from the P-wave velocity.%基于东北地区满洲里-绥芬河和内蒙古东乌珠穆沁旗-辽宁东沟两条地学断面研究所给出的、固定台站接收函数所得到的以及其它深地震探测所获得的莫霍面深度值，在给定参数搜索范围、适当的初始温度等条件下，用小波分析所提取的反映莫霍面起伏的4阶逼近重力异常作为反演的约束条件，利用模拟退火算法（SA），反演了该区域地壳内密度随深度变化的指数分布函数，得出地壳表层与地幔的密度差为-0.9g·cm-3，衰减系数为0.02。通过与由地震纵波波速转换而来的地壳内密度结构的对比，表明本文反演出的密度指数模型可以很好地反映地壳密度的纵向变化。