小多道地震震源效果在海域活动断裂探测中的对比研究  

A COMPARATIVE STUDY OF SOURCE EFFECT BASED ON MINI-MULTICHANNEL SEISMIC PROFILE IN MARINE ACTIVE FAULT DETECTION

作　　者：易虎 詹文欢[1,2,3] 闵伟 吴晓川[1] 李健 冯英辞[1,2] 任治坤 YI Hu;ZHAN Wen-huan;MIN Wei;WU Xiao-chuan;LI Jian;FENG Ying-ci;REN Zhi-kun(Key Laboratory of Ocean and Marginal Sea Geology,South China Sea Institute of Oceanology,Innovation Academy of South China Sea Ecology and Environmental Engineering,Chinese Academy of Sciences,Guangzhou 511458,China;Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou),Guangzhou 511458,China;University of Chinese Academy of Sciences,Beijing 100049,China;Institute of Geology,China Earthquake Administration,Beijing 100029,China)

机构地区：[1]中国科学院边缘海与大洋地质重点实验室,南海海洋研究所,南海生态环境工程创新研究院,广州511458 [2]南方海洋科学与工程广东省实验室(广州),广州511458 [3]中国科学院大学,北京100049 [4]中国地震局地质研究所,北京100029

出　　处：《地震地质》2022年第2期333-348,共16页Seismology and Geology

基　　金：国家重点研发计划项目(2017YFC1500401);国家科技基础资源调查专项(2017FY201406);南方海洋科学与工程广东省实验室(广州)人才团队引进重大专项(GML2019ZD0204)共同资助。

摘　　要：海域地震区划与活动断裂的探测和识别密切相关。文中在台湾海峡闽东南隆起带开展了活动断裂的地球物理探测研究,选取GI枪震源与电火花震源剖面进行对比分析,发现了晚更新世以来活动的3条基底断裂构造和2条垂向延伸较小的细小断裂。基底断裂可在GI枪震源剖面和电火花震源剖面上识别,细小断裂则只能在电火花剖面上识别;3条基底断裂在2种剖面上的错断地层位置、几何形态接近,但断裂周围的地层形态及次级断裂展布样式受分辨率的影响存在成像差异。相似的断裂探测结果体现了这2种方法的有效性,而剖面成像差异则说明在实际工作中开展组合探测的必要性。基于2种数据的融合结果,对断裂F_(1)的构造属性进行更为详细的分析说明:断裂F_(1)是基底先存断裂晚更新世活化的结果,为一坳陷边界断层,呈伸展正断活动,分析认为其应归属为华南沿海滨海断裂带。因此,在海域地震区划和海域地震危险性评价工作中,应重视多种探测方法的组合使用,以便获取更加详实的断裂信息。The neotectonic activity is intense in the Taiwan Straits and the coastal area of South China.This region is one of the earthquake-prone areas of the world.In history,earthquakes of magnitude 6-7 occurred repeatedly in this region with a high recurrence rate.Therefore,this area has always been the focus of seismicity research and coastal earthquake prevention and disaster reduction.The exploration of active faults is the basis for seismic zoning,but the detection and identification of active faults in sea area are more difficult because of the coverage of sea water,which leads to a large number of“blind areas”in marine fault exploration for a long time.Seismic exploration methods are economical,suitable and efficient in detecting active faults in the sea area.This study compares the detection effect of different seismic sources.In this study,geophysical exploration of active faults was carried out in the southeast Fujian uplift zone in the Taiwan Straits.A mini-multichannel seismic profile of GI gun source and sparker source at the same location was selected for comparative analysis and illustration.Five reflection interfaces(T_(1)—T_(4),Tg)were interpreted on the GI gun profile,and five sets of seismic sequences(A—E)were classified.Six reflection interfaces(T′_(1),T_(1)—T_(4),Tg)were interpreted on the sparker source profile,and six sets of seismic sequences(A—D and E_(1)—E_(2))were classified.Three basement faults and two shallow faults with small vertical extension were found,which are active since the late Pleistocene.Among them,the scale of fault F_(1) is large,the displacement of the basement fault F_(1) is 51 ms,and the overall displacement of(T_(1)—T_(4))in the sediments is 35 ms.Faults F_(2)—F_(5) are located on the continental side of fault F_(1) and can be combined into grabens and horsts in forms,which are inferred to be the associated faults of Fault F_(1).It’s found that basement faults can be identified by both GI gun profile and sparker source profile,while the small faults c

关 键 词：电火花震源 GI枪震源 小多道地震 活动断裂 台湾海峡 

分 类 号：P315.2[天文地球—地震学]