热带海洋学报 ›› 2021, Vol. 40 ›› Issue (5): 111-122.doi: 10.11978/2020131

• 海洋地球物理学 • 上一篇    下一篇

南海北部陆缘OBS2018-H2测线地壳结构初步结果*

苏晓康1,3(), 赵明辉1,2,3(), 李子正1,3, 袁野1,3, 王星月1,3, 程锦辉1,3, 张佳政1,2   

  1. 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
  • 收稿日期:2020-11-10 修回日期:2021-01-04 出版日期:2021-09-10 发布日期:2021-01-08
  • 通讯作者: 赵明辉
  • 作者简介:苏晓康(1995—), 男, 河南省开封市人, 硕士研究生, 研究方向为海洋地球物理。email: suxiaokang@scsio.ac.cn
  • 基金资助:
    国家自然科学基金(41730532);国家自然科学基金(91958212);国家自然科学基金(42002222);国家自然科学基金(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)(GML2019ZD0204);广东省自然科学基金团队项目(2017A030312002)

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

SU Xiaokang1,3(), ZHAO Minghui1,2,3(), LI Zizheng1,3, YUAN Ye1,3, WANG Xingyue1,3, CHENG Jinhui1,3, ZHANG Jiazheng1,2   

  1. 1. 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
    2. Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
    3. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2020-11-10 Revised:2021-01-04 Online:2021-09-10 Published:2021-01-08
  • Contact: ZHAO Minghui
  • Supported by:
    Natural Science Foundation of China(41730532);Natural Science Foundation of China(91958212);Natural Science Foundation of China(42002222);Natural Science Foundation of China(91858212);Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(GML2019ZD0204);Guangdong Natural Science Foundation research team project(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。

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

Abstract:

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.

Key words: data processing, seismic phase, initial velocity model, crustal thickness, continent-ocean transition, northern margin of South China Sea

中图分类号: 

  • P712.83