桥头集-东关断裂合肥盆地段活动特征  

Characteristics of the Activity of Hefei Basin Segment of Qiaotouji-Dongguan Fault

作　　者：方良好 疏鹏 路硕[1,2] 郑颖平 杨源源[1,2] 潘浩波 李鹏飞[1] Fang Lianghao;Shu Peng;Lu Shuo;Zheng Yingping;Yang Yuanyuan;Pan Haobo;Li Pengfei(Anhui Earthquake Administration,Hefei 230031,China;Key Laboratory of Research on the South Section of the Tan-Lu Fault Zone,Hefei 230031,China)

机构地区：[1]安徽省地震局,合肥230031 [2]郯庐断裂带中南段重点研究室,合肥230031

出　　处：《震灾防御技术》2020年第4期767-776,共10页Technology for Earthquake Disaster Prevention

基　　金：中国地震局地震科技星火计划青年项目(XH19017Y);合肥市地震活断层探测及地震危险性分析(340100)。

摘　　要：北西走向的桥头集-东关断裂与郯庐断裂带南段相交切,横跨合肥盆地及其东缘的隆起区,在合肥盆地内呈隐伏状态。本研究跨桥头集-东关断裂合肥盆地段布设3条浅层地震勘探测线,揭示断裂浅部构造特征。解译出的F_(P1)、F_(P2)和F_(P3)断层性质相同,倾向一致,上断点深度相近,反映出桥头集-东关断裂合肥盆地段是一条走向NW、倾向SW、具有逆断分量的断裂。3条浅层地震反射剖面中第四系的底界面反射波组TQ呈连续近水平展布,表明桥头集-东关断裂两侧的第四系厚度无明显变化。在浅震剖面解译的基础上,布设了1条跨断层钻孔联合剖面,剖面揭露出的第四系没有被错动。结合本区第四系地层发育情况及钻孔地层年龄分析,认为桥头集-东关断裂中更新世以来不活动。根据本文探测结果,尚不能排除桥头集-东关断裂早更新世有一定的弱活动。The Qiaotouji-Dongguan fault,which intersects with the southern part of the Tanlu fault zone,strikes NW.It straddles the Hefei Basin and the eastern uplift area,and is concealed in the Hefei basin.In this study,3 shallow seismic exploration lines are set up at Qiaotouji-Dongguan Fault in Segment of Hefei Basin,which well reflect the shallow structural characteristics of the fault.The interpreted faults F_(P1),F_(P2) and F_(P3) have the same property,same tendency and similar fault depth at the upper breakpoint,reflecting that the Qiaotouji-Dongguan Fault in Segment of Hefei Basin is a fault with NW strike,SW tendency and reverse fault component.In the three shallow seismic reflection sections,the bottom boundary of TQ is distributed continuously and nearly horizontally,indicating that the thickness of the Quaternary on both sides of Qiaotouji-Dongguan Fault has no obvious change.Based on the seismic reflection profile,a composite drilling geological section is set up.The results show that the Quaternary exposed by the composite drilling geological section has not been staggered.According to the Quaternary strata in this area and the age of borehole strata,Qiaotouji-Dongguan Fault has not been active since the Middle Pleistocene.According to the results of this paper,it can not be ruled out that the Qiaotouji-Dongguan Fault had a certain weak activity in the early Pleistocene of Quaternary.

关 键 词：桥头集-东关断裂 合肥盆地 地震反射剖面 钻孔联合剖面 断裂活动性 

分 类 号：P315.2[天文地球—地震学]