青岛大沽河断裂活动性初步研究

A Preliminary Study of the Activity of Dagu River Fault in Qingdao Area

大沽河断裂是青岛地区规模较大的一条隐伏断裂,前人对该断裂没有进行过详细的研究。由于缺乏足够的证据,无法确定该断裂的展布和产状,更加无法确定其活动性。本文首先基于地质图布设几条地球物理勘探测线,根据物探结果,选取三处异常点分别布设若干钻孔进行钻探验证。根据钻孔地层结构绘制三个联合地质剖面,剖面揭示有断裂通过,从而在土层中选取四个土样进行年代学测试。研究表明,大沽河断裂通过了地球物理勘探的三处异常点,基本确定了断裂走向;年代学测试结果表明该断裂为早更新世或中更新世早中期断裂,不属于活动断裂;根据统计规律,该断裂不会发生破坏性地震,也不会造成地表破裂,重大建设工程不需要避让该断裂。本研究具有十分重要的意义。

The Dagu River fault is a large buried fault in Qingdao area,which extends from the north to the south along the Dagu River.There have been no previous studies that cautiously focused on this fault.As there is no adequate analysis data,researchers are unable to ensure the fault distribution and attitude.In addition,they cannot ensure the fault activity.In this study,we first arranged several geophysical exploration lines based on the geological map.Then,according to the geophysical exploration,we selected three abnormal sites to drill several holes and subsequently developed three combined geological profiles with respect to stratum.On the basis of the geological map,three abnormal sites,and combined geological profiles,we found where the fault passes through.We selected four soil samples from the stratum to test their chronology.Research shows that the Dagu River fault passes through the three abnormal sites because the stratum changed in different holes.We virtually make sure the fault's trend and distribution.Chronology test report shows that the age of the Dagu River fault is early Pleistocene or early mid-Pleistocene,but it is not an active fault.According to statistical regularity,the Dagu River fault will not initiate any destructive earthquakes or rupture the earth's surface.Therefore,large-scale projects should not be away from the fault.As numerous large-scale projects will be initiated in Qingdao area,conducting this study is essential in actual projects.