铺前—清澜断裂西支晚更新世活动特征

摘要

The marine shallow seismic exploration survey shows that Puqian--Qinglan fault extends NW sea-wards.It is a high angle normal fault striking NW--SE and dipping SW.On the seismic profile, the fault offsets Quaternary strata.Further study is undertaken combining drilling data with sequence stratigraphy,lithofacies analy-sis and dating,and a geological section across well boreholes is established,which reveals that the fault is a normal fault,dipping SW,and the fault throw is more than 4.0 m.The latest activity of the fault occurred in Late Pleisto-cene and it was characterized by extensional feature in Quaternary.The average vertical slip rate of the fault is 0.15 mm/a.%海域浅层地震探测调查表明,铺前—清澜断裂向北西海域方向延伸,断裂走向NW--SE,倾向SW,为高倾角的正断层;在地震剖面上,断裂断错了第四系地层;进一步应用钻探技术对铺前—清澜断裂进行探测研究,结合层序地层学、岩性岩相分析与年代测定等方法建立了钻孔联合剖面,揭示断层性质为正断层,倾向SW,断距>4.0 m,断层的最新活动时代为晚更新世,第四纪表现为张性活动,断裂的平均垂直速率为0.15 mm/a.