河套断陷带包头断裂第四纪活动性研究  

THE STUDY OF QUATERNARY ACTIVITY OF BAOTOU FAULT IN HETAO ACITVE FAULT SUBSIDENCE ZONE

作　　者：马兴全 孙杰 赵显刚 王文旭 蔡颖哲 万娜 

机构地区：[1]河南省地震局,郑州450016

出　　处：《地震地质》2016年第4期874-884,共11页Seismology and Geology

基　　金：中国地震局"中国城市活动断层探测与地震危险性评价"项目资助

摘　　要：已有资料表明包头断裂呈NE走向隐伏展布于河套断陷带内次级盆地白彦花凹陷的东边界,目前关于该断裂的活动性资料尚需补充。鉴于包头断裂发育于由乌拉山山前断裂带和大青山山前断裂带组成的传递斜坡内部,研究其活动性不仅有助于深入讨论相邻活动断裂带的连接方式及活动响应,还可为更全面地认识河套断陷带的地震构造特征提供资料。控制性浅层地震勘探和钻孔联合剖面综合探测是当前研究隐伏断裂活动性非常有效的方法之一。跨包头断裂的浅层人工地震纵波反射剖面显示该断裂为倾向NW的正断层,深度约75m处的强反射层(Tg)位错量约为25m;在此基础上实施的联合钻探结果进一步揭示了该断裂具有明显的生长断层特征,其上断点止于地层顶部埋深45.6m的早更新世棕红色黏土层中,上覆上更新统与其为平行不整合接触。包头断裂属于早更新世断裂。Existing achievements about Baotou Fault demonstrate it as a buried eastern boundary of the Baiyanhua Basin in Hetao active fault subsidence zone,striking NE. More data is needed to assess its activity. Located in the relay ramp between Wulashan Fault and Daqingshan Fault,Baotou Fault＇s activity is of great importance to discuss the linkage mode and the response to the earthquake of the adjacent fault. Also it is necessary to the knowledge of the characteristic of the seismic tectonic in local area. Recently it is prevalent to combine shallow seismic profile and composite drilling section to study the activity of the buried fault. Shallow seismic profile indicates that Baotou Fault is a normal fault,inclining to NW. The displacement of the Tg at 75 m underground is 25 m. Composite drilling section indicates that it is a growth fault,the up-break point of which is 45. 6m underground and ends in brownish red clay strata of early Pleistocene. In comparison,the upper Late Pleistocene strata are out of the influences of the tectonic subsidence zone. Baotou Fault＇s activity is limited to the early Pleistocene.

关 键 词：河套断陷带 传递斜坡 包头断裂 浅层地震勘探 钻孔联合剖面 

分 类 号：P315.2[天文地球—地震学]