太行山南端浅层速度结构成像和隐伏断裂探测
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摘要
利用太行山南端的深地震反射剖面数据,运用初至波层析成像方法反演得到该区域的浅层P波速度结构和基底面展布形态,发现剖面浅部的P波速度变化与沉积盖层厚度和断裂分布有着较好的对应关系。利用跨断裂完成的浅层地震反射剖面,对区域内2条第四纪隐伏活动断裂进行高分辨率成像。结果表明,汤西断裂为东倾的正断层,控制汤阴地堑的西边界,活动年代为中更新世;汤东断裂为西倾的正断层,是汤阴地堑的主控边界断裂,活动年代为晚更新世。
We apply a tomography method of first-arrival travel-time acquired from deep seismic reflection profile to explore the shallow P-wave velocity structure and the basement distributed shape of the southern margin of Taihang mountains.The results indicate a good corresponding relationship among the variations in P-wave velocity,the thickness of sedimentary cover,and the position of the faults.In order to probe the characteristics of active faults in the research area,two shallow seismic reflection profiles crossing the buried faults are carried out.The results show that Tangxi fault is a normal fault plunging towards the east,controlling the western boundary of the Tangyin graben.It is active during the middle Pleistocene.Tangdong fault is a west dipping fault,and is the main controlling boundary fault of the Tangyin graben.The latest activities can be traced to the early period of late Pleistocene.