土壤氡对郯庐断裂宿迁段F5断裂探测和活动性的研究

Detection and Activity of the Fault F5 in Suqian Segment of the Tanlu Fault by Using Soil Radon

郯庐断裂带宿迁段多年来一直被列为江苏地震重点关注区域。在该区域展开了多期活断层探测和工程地震安全性评价工作,地震监测已经建成了测震、形变、电磁、流体等多种手段。用气体地球化学方法开展相关研究,探索活动断层运动和地震发生之间的相互关系,是对该地区地震科学研究的一种补充,其有着十分重要的意义。沿郯庐断裂带宿迁段F5断裂布设土壤氡测线并获得相关数据,结合地质勘察、浅层人工地震等资料进行综合分析,结果表明该区域内土壤氡探测结果对断裂带的位置、断层类型和特征、断层活动性具有较好的指示性。土壤氡探测展示F5断裂两条分支断裂F5-1、F5-2的位置,氡浓度异常形态与断层特征存在一定的对应关系,并利用土壤氡浓度强度为指标,初步判断郯庐断裂带宿迁段F5断裂2条分支断裂的相对活动性。

The Suqian segment of the Tanlu fault has been a focus area of Jiangsu earthquake for many years.Multiphase active fault detection and engineering seismic safety evaluation have been carried out in this area.In addition,many earthquake monitoring methods have been established,such as seismometry,deformation,electromagnetic,and fluid,among others.It is of great significance to study the relationship between active fault movement and earthquake occurrence using gas geochemical method.The two main faults(F5-1 and F5-2)composing the fault F5 in Suqian section of the Tanlu fault are inclined to each other and developed nearly vertically.In this paper,five survey lines of soil radon were set up along the fault F5.Combined with the data of geological survey and shallow artificial earthquake,the results showed that the detection results of soil radon in the study area have a clear indication for the fault location,fault type and characteristics,and fault activity.Soil radon detection shows the location of fault F5-1 and fault F5-2.There is a certain correspondence between the abnormal shape of radon concentration and the characteristics of fault.The relative activity of the two branch faults of F5 fault in the Suqian section of the Tanlu fault zone is preliminarily judged using the concentration intensity of soil radon as index.