南海北部陆缘OBS2018–H2测线地壳结构初步结果  

Preliminary results of the crustal structure along OBS2018-H2 in the northern continental margin of the South China Sea

作　　者：苏晓康 赵明辉[1,2,3] 李子正 袁野 王星月[1,3] 程锦辉 张佳政 SU Xiaokang;ZHAO Minghui;LI Zizheng;YUAN Ye;WANG Xingyue;CHENG Jinhui;ZHANG Jiazheng(CAS 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 510301,China;Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou),Guangzhou 511458,China;University of Chinese Academy of Sciences,Beijing 100049,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,广东广州510301 [2]南方海洋科学与工程广东省实验室(广州),广东广州511458 [3]中国科学院大学,北京100049

出　　处：《热带海洋学报》2021年第5期111-122,共12页Journal of Tropical Oceanography

基　　金：国家自然科学基金(41730532、91958212、42002222、91858212);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);广东省自然科学基金团队项目(2017A030312002)。

摘　　要：南海北部陆缘洋陆转换带实施的OBS2018–H2测线的地壳速度结构,将为探讨南海张裂-破裂机制提供重要证据。文章介绍了OBS2018–H2测线前期数据处理流程,包括多道反射地震数据处理、海底地震仪OBS(Ocean Bottom Seismometer)数据格式转换、炮点和OBS位置校正,以及OBS震相的初步识别,并对地壳结构进行了初步分析。结果表明:炮点和OBS位置校正效果良好;多道反射地震数据为建立初始速度模型提供了良好约束;OBS综合地震剖面识别了多组清晰的P波震相,包括Pw、Pg、PmP和Pn震相。根据测线西侧OBS36、OBS37两台站的震相分布特征初步估算台站下方地壳厚度约为6~7km,与根据多道地震剖面LW3的双程走时估算的厚度6~9km大致相符。The crustal velocity structure along profile OBS2018-H2 located in the continent–ocean transition can provide important evidence for the rifting-breakup mechanism of the northern margin of the South China Sea(SCS).The preliminary data processing steps are presented in this paper,including multi-channel reflective data processing,OBS(Ocean Bottom Seismometer)data format conversion,shot and OBS relocation,and identification of OBS seismic phases,followed by a preliminary analysis of the crustal structure.Our results show that relocations of shots and OBSs are effective and reliable.The multi-channel seismic(MCS)profile provides a good constraint for building the initial velocity model.Several groups of seismic phases,e.g.,Pg,PmP and Pn,are clearly identified in OBS comprehensive seismic profiles.Based on the distribution characteristics of the OBS36 and OBS37 seismic phases on the west side of OBS2018–H2,the thickness of the crust below these two stations is estimated to be about 6~7 km.It is roughly equivalent to the thickness of 6~9 km estimated from the two-way travel time in MCS profile LW3.

关 键 词：数据处理 震相 初始速度模型 地壳厚度 洋陆转换带 南海北部陆缘 

分 类 号：P712.83[天文地球—海洋科学]