用浅层地震勘探资料研究蓟运河断裂的第四纪活动特征

Quaternary activity characteristics of the Jiyunhe fault revealed by shallow seismic prospecting data

蓟运河断裂是天津地区东北部的一条重要断裂,是张家口—渤海构造带的组成部分。由于未对蓟运河断裂的活动性进行过专门探测研究,其空间展布及第四纪活动性一直存在争议。经广泛收集资料确定蓟运河断裂的大致展布,并布设9条人工地震测线,采用可控震源对该断裂进行探测。结果表明:蓟运河断裂不是一条南北贯通的断裂,其大致分为北西段和南东段两段。蓟运河断裂北西段主要呈断陷特征,切割深、断距大,是燕山褶皱带和沧县隆起的边界断裂,为晚更新世早期断裂;南东段错断不明显,推测以走滑运动为主,为早-中更新世断裂。

As is an important fault in the northeast of Tianjin,Jiyunhe fault is a component of the Zhangjiakou-Bohai tectonic belt.Due to the lack of special exploration and research on its activity,the spatial distribution and Quaternary activity of the Jiyunhe fault is always in dispute.Through extensive data collection,the general distribution of Jiyunhe fault was determined.Then 9 artificial seismic lines were arranged in the study area,and the vibrator was used to detect the fault.The results showed that the Jiyunhe fault is not a north-south fault,but roughly divided into two segments:the northwest segment and the southeast segment.The northwest section of Jiyunhe fault is mainly characterized by fault depression with deep cutting and large fault distance.It is an early fault of late Pleistocene and also the boundary fault of Yanshan fold belt and Cangxian uplift.The fault in the southeast section is not obvious,and it is speculated to be an early-middle Pleistocene fault which is dominated by strike slip movement.