东海陆架深地震震相与地壳结构特征  

Deep seismic phases and crustal structure in the East China Sea shelf

作　　者：赵俐红 李一泉 刘欣悦 郑彦鹏 赵强 刘凯 支鹏遥 ZHAO Lihong;LI Yiquan;LIU Xinyue;ZHENG Yanpeng;ZHAO Qiang;LIU Kai;ZHI Pengyao(College of Earth Science and Engineering,Shandong University of Science and Technology,Qingdao 266590,China;Hubei Provincial Key Laboratory of Marine Geological Resources/College of Marine Science and Technology,China University of Geosciences(Wuhan),Wuhan 430074,China;The First Institute of Oceanography,Ministry of Natural Resources,Qingdao 266061,China;Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,China)

机构地区：[1]山东科技大学地球科学与工程学院,山东青岛266590 [2]海洋地质资源湖北省重点实验室/中国地质大学(武汉)海洋学院,湖北武汉430074 [3]自然资源部第一海洋研究所,山东青岛266061 [4]青岛海洋科学与技术试点国家实验室,山东青岛266237

出　　处：《中山大学学报（自然科学版）（中英文）》2022年第1期84-93,共10页Acta Scientiarum Naturalium Universitatis Sunyatseni

基　　金：国家自然科学基金(41676039);国家自然科学基金委员会-山东省人民政府海洋科学研究中心联合资助项目(U1606401)。

摘　　要：东海因其特殊的构造位置而成为海洋科学研究的焦点,是海陆地质对比和深部地壳结构研究的理想场所。为此,本文基于在东海陆架地区布设的NW-SE向主动源广角深地震剖面,通过13个站位的震相分析,识别出丰富的Ps、PsP、Pg、PcP和PmP震相。利用射线追踪和走时拟合得到P波速度结构模型。模型表明,中、新生代沉积层埋深东高西低,测线西侧隆起处埋深约1.5~3.5 km,速度1.7~3.6 km/s;测线东侧凹陷处埋深约3.5~9.0 km,速度1.7~5.4 km/s;深部地壳分为上、下2层,其中上地壳底界面埋深13.0~14.5 km,界面起伏不明显,速度5.6~6.2 km/s,下地壳速度6.3~6.9 km/s,底部无明显速度扰动,推测未发育大规模的岩浆底侵及地幔上涌活动;莫霍面埋深26.5~28.5 km,具有凸-凹-凸的起伏形态;地壳厚度17.5~27.0 km,为有所减薄的陆壳,具有西厚东薄的特征,其中西侧隆起处拉张因子1.2,东侧凹陷处拉张因子1.3~1.8,表明东海陆架东部较西部经历了更加强烈的地壳拉伸减薄活动。The East China Sea(ECS)is becoming attractive for marine scientific research owing to its special tectonic location,being recognized as an ideal site for sea-land geological comparison and deep crustal structure research.A deep seismic survey line has been deployed along the NW-SE direction in the ECS shelf to study the deep crustal structure.Abundant seismic phases,such as Ps,PsP,Pg,PcP,and PmP,are identified by analyzing the obtained 13 stations based on wide-angle reflection and refraction theory.The model shows that the burial depth of the Mesozoic and Cenozoic sedimentary is deeper in the east than in the west:in the west segment,it is about 1.5-3.5 km,with the velocity of 1.7-3.6 km/s,while in the east segment,it is about 3.5-9.0 km with the velocity of 1.7-5.4 km/s.The crust is divided into two layers:the upper crust,which has the velocity of 5.6-6.2 km/s,the bottom boundary in the depth of 13.0-14.5 km with a little undulation,and the lower crust,which has the velocity of 6.3-6.9 km/s,the bottom boundary in the depth of 26.5-28.5 km with some undulation.The bottom of the lower crust has no obvious velocity disturbance,implying that there are no large-scale magma activities or mantle upwelling.The crustal thickness is 17.5-27.0 km,presenting a thinned continental crust,and more thinning in the east.The stretching factor is estimated to be 1.2 for the west segment and 1.3-1.8 for the east segment,indicating that the east part of the ECS shelf has experienced more intense crustal stretching and thinning activities than the west part.

关 键 词：东海陆架 OBS探测 地震震相 地壳结构 

分 类 号：P716[天文地球—海洋科学] P738