萧山-球川断裂富阳-建德段第四纪活动性研究

Characteristic of Quaternary Activities of Fuyang-Jiande Segment of Xiaoshan-Qiuchuan Fault

萧山-球川断裂是浙江地区1条大规模的北东向断裂,在该断裂附近曾发生过多次破坏性地震。本文通过地质调查、电法勘探和探槽开挖等方法,对萧山-球川断裂富阳—建德段第四纪活动性进行了研究。萧山-球川断裂富阳—建德段的遥感影像线性特征清楚,对地貌的控制作用较为明显,对山前的第四系发育有明显影响。通过对断裂露头剖面的分析,认为萧山-球川断裂富阳—建德段活动性质以走滑兼具逆冲为主。通过本次开挖的富阳峙山村探槽,结合ESR年龄测定,判定该断裂在第四纪早、中期有过活动,但未断错上覆中更新统上部地层,其最新活动时代为早、中更新世。

Xiaoshan-Qiuchuan fault in NE-direction is one of the large-scale faults in Hangzhou area, along which there have been many destructive earthquakes. The activity of this fault in Quaternary is an important reference for Hangzhou area in carrying out seismic prevention and mitigation work. Through field investigation, electric exploration and trench excavation, we have studied the Quaternary activities of Fuyang-Jiande segment of Xiaoshan-Qiuchuan fault. The Fuyang-Jiande segment of Xiaoshan-Qiuchuan fault shows clear lineation on remote sensing image, and has a significant effect on Quaternary development of the piedmont and the control effect on the landscape. The activity feature of Fuyang-Jiande segment of Xiaoshan-Qiuchuan fault is dominated by thrust and strike-slip inferred from the research on the fault exposed profile. Based on trench excavation which is located in Fuyang Zhishan village, combing electron spin resonance dating, we found that the fault was active in early and middle Quaternary, and it has not cut through the above strata of middle Pleistocene.