热带海洋学报

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利用接收函数方法约束西沙碳酸盐岩台地沉积厚度与速度结构

黄海波1,2,丘学林1,2,3,龙根元4,5,矫东风4,5,韩孝辉4,5   

  1. 1. 中国科学院边缘海与大洋地质重点实验室(中国科学院南海海洋研究所),广东 广州 511458;

    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

    4. 海南省海洋地质资源与环境重点实验室,海南 海口 570206;

    5 海南省海洋地质调查研究院,海南 海口 570206;

  • 收稿日期:2022-02-16 修回日期:2022-04-11 出版日期:2022-04-15 发布日期:2022-04-15
  • 通讯作者: 黄海波
  • 基金资助:

    国家自然科学基金项目(42176081; 42174110);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);海南省海洋地质资源与环境重点实验室开放课题(HNHYDZZYHJKF003)

Thickness and velocity structures of carbonate platform sediments in Xisha Islands constrained by receiver function method

HUANG Haibo1,2, QIU Xuelin1,2,3, LONG Genyuan4,5, JIAO Dongfeng4,5, HAN Xiaohui4,5   

  1. 1.  Key Laboratory of Ocean and Marginal Sea Geology (South China Sea Institute of Oceanology, Chinese Academy of Sciences), Guangzhou 511458, China;

    2.  Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China;

    3.  University of Chinese Academy of Sciences, Beijing 100049, China

    4.  Hainan Key Laboratory of Marine Geological Resources and Environment, Haikou 570206, China;

    5.  Marine Geological Institute of Hainan Province, Haikou 570206, China

  • Received:2022-02-16 Revised:2022-04-11 Online:2022-04-15 Published:2022-04-15
  • Contact: HUANG Hai-bo
  • Supported by:

    National Natural Science Foundation of China (42176081; 41274110); Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou)(GML2019ZD0204); Open Project of Hainan Key Laboratory of Marine Geological Resources and Environment (HNHYDZZYHJKF003)

摘要: 碳酸盐岩台地的沉积厚度和弹性波速度是评估珊瑚礁发育规模以及结构稳定性的重要参数。本文根据西沙地区琛航岛和永兴岛流动地震台站所记录的远震接收函数波形,通过识别沉积底部产生的转换横波及其多次波震相,精确拾取震相走时信息。同时参考岛屿钻井资料和人工地震探测结果,计算获得了台站下方碳酸盐岩台地沉积的厚度、平均纵波速度和波速比。结果显示:永兴岛和琛航岛下方沉积体的平均纵波速度约为3.5km·s-1、波速比约为2.42、平均厚度分别约为1.35km和1.55km。计算获得的平均厚度与西沙钻至基底的测井结果较为一致(约1.257km)。琛航岛沉积厚度略大于永兴岛(约200m),表明碳酸盐岩台地沉积基底的起伏或与生物礁沉积相的差异有关。

关键词: 碳酸盐岩台地, 速度结构, 波速比, 接收函数, 西沙群岛

Abstract: Thickness and elastic wave velocity are important parameters for evaluating coral reef’s size and structural stability. This study collected the receiver functions from two portable seismic stations on Chenhang Island and Yongxing Island in the Xisha area. Travel times of the P-to-S converted waves and their multiple phases generated at the sediment bottom of the carbonate platform are accurately picked up. At the same time, the thickness, average P-wave velocity, and velocity ratio of the carbonate platform sediments were calculated by referring to drilling data and artificial seismic exploration results. The results show that the average P-wave velocity of the platform sediments on Yongxing Island and Chenhang Island is about 3.5 km·s-1, the Vp/Vs ratio is 2.42, and the average thicknesses are about 1.35 km and 1.55 km respectively. The calculated thicknesses are consistent with that of the well on Yongxing Island which reaches the reef bottom at about 1.257 km. The sediment thickness of Chenhang Island is slightly larger than that of Yongxing Island (about 200m), which reflects the fluctuation of the basement beneath the island or related to the reef growth faces.

Key words: carbonate platform, velocity structure, Vp/Vs ratio, receiver function, Xisha