北京地区主要活动断裂深部速度结构特征及强震构造分析

根据分别由人工地震测深速度结构剖面数字化和天然地震层析成像建立的北京地区三维地壳速度结构模型,本文绘制了剖面图。同时将剖面两侧5km的地震震中投影到剖面上,分析了北京地区主要活动断裂的深部速度结构特征,证实两种方法得到的地壳速度结构模型具有很大的相似性。同时,顺义凹陷、马池口凹陷下方存在近垂直的深断裂,此深断裂可能为未来的发震断裂,地壳浅部与此对应的活动断裂是顺义-前门-良乡断裂北段、黄庄-高丽营断裂北段以及清河断裂,地壳内部的深断裂与地壳浅部控制盆地发育的活动断裂之间可能处于"汇而未交"的状态,具有地震孕育的深部构造背景。

Velocity Structure Beneath the Active Faults in Beijing Area and Their Seismo-tectonic Characteristics

Velocity structure beneath the active faults in Beijing area has been discussed in the paper,based on the digital crust model of velocity from Deep seismic sounding profiles and tomographic imaging of P wave.We found that there exist some near vertical deep faults beneath Shunyi Depression and Machiko Depression,which are very likely to be earthquake faults in future.In superficial crust,the north segment of Shuiyi-Qianmen-Liangxiang fault,the north segment of Huangzhuang-Gaoliying fault and Qinghe fault are in the trend of ＂meeting together＂ but without intersection.This kind of seismo-tectonic state is of great potential to generate large earthquakes