利用反射地震资料研究吴忠地区崇兴断裂精细结构

Research on Detailed Structure of Chongxing Fault in Wuzhong Area:Based on Reflection Seismic Data

为了研究宁夏吴忠地区东部隐伏断层的位置、空间展布以及内部构造特征,在可能存在崇兴断层的位置布设了几条高分辨率的浅层地震反射测线。结果表明,崇兴断层为走向北北东、倾向西西北的正断层。浅层反射地震测线控制的崇兴断层延伸长度约12 km,断层倾角较陡,近于直立,南部的WJQ测线上的断点F_(P1)揭示该断层可分辨上断点错断了第四系底界面T_Q,而向北的SJDD测线上的断点F_(P5)和WJZ测线上的断点F_(P6)揭示,该断层向上错断了第四系内部界面T_(02),反映该断层活动性具有北段相对强而南段相对弱的特点。

In order to study the location and the spatial distribution of buried faults and the crustal shallow structure in the eastern part of Wuzhong area in Ningxia,we lay several high resolution shallow seismic reflection lines where the Chongxing fault may exist.The results show that the Chongxing fault is a NNE-trending normal fault.The interpretation of shallow reflection seismic sections shows that the fault extends about 12 km in length and has a steeper,nearly upright,dip angle.The breakpoint F P1 on the southern WJQ line reveals that the Quaternary bottom interface T Q is broken by the Chongxing fault,while the breakpoint F P5 on the northern SJDD line and the breakpoint F P6 on the WJZ line reveal that the fault intrudes upwards to the Quaternary internal interface T 02,which seems to reflect that the fault activity is relatively strong in the northern section and relatively weak in the southern section.