摘要
南海地区位于欧亚板块、菲律宾海板块以及印度‒澳大利亚板块的交汇地带,其复杂的构造背景使其成为研究板块相互作用与构造变形的理想区域。深入探讨南海现今的构造变形特征,分析其演化过程,并揭示其动力学机制,对区域灾害风险评估具有重要意义。本文基于全球导航卫星系统(GNSS)观测数据,分析了南海及邻区的速度场、应变率场以及块体边界的活动特征。结果表明,南海地块及其周边块体内部变形较弱,主要以刚性块体形式运动,各块体之间表现出明显的差异运动,并通过边界构造变形进行调节。其中,南海地块东边界变形最为强烈,通过南海洋壳的俯冲和马尼拉海沟的左旋走滑,吸收菲律宾海板块向WNW方向的快速运动。相比之下,南海地块与相邻块体之间的边界变形较弱,主要通过边界断裂的右旋走滑来调节块体间的相对运动。南海地块的形成与演化过程受到周边板块运动的共同影响。现今的构造变形特征显示,菲律宾海板块向WNW方向的运动对南海地块的影响最显著,而印度板块和澳大利亚板块的作用相对较弱。
The South China Sea,located at the convergence of the Eurasian Plate,the Philippine Sea Plate,and the Indo-Australian Plate,is distinguished by its intricate tectonic setting,making it an ideal site for studying plate interactions and their associated deformation mechanisms.Comprehending the present-day deformation patterns,evolutionary history,and underlying dynamic processes in this region is crucial for assessing regional seismic hazards.In this study,we utilized Global Navigation Satellite System(GNSS)observations to quantify crustal velocity fields,strain rate distributions,and boundary fault activities across the South China Sea Basin and its adjacent areas.Our findings reveal that the internal deformation within the South China Sea Basin and surrounding blocks is minimal,with these regions behaving as rigid blocks.Specifically,within the South China Block reference frame,the South China Sea and Borneo exhibit westward movement,while the Indochina Block moves in a NNW direction.The Philippine Sea Plate converges rapidly toward the South China Sea Block in a WNW direction.Significant differential motions between the blocks are accommodated through strain partitioning along boundary-parallel strain localization zones.Notably,deformation along the eastern boundary of the South China Sea is the most pronounced.The subduction of the South China Sea Basin’s oceanic crust and the left-lateral transtension along the Manila Trench jointly accommodate the rapid WNW-directed motion of the Philippine Sea Plate.Conversely,deformation along the boundaries between the South China Sea and other blocks is limited,with relative motions regulated by distributed right-lateral shear along boundary faults.The formation and evolution of the South China Sea are influenced by the dynamics of the surrounding plates.The current deformation characteristics indicate that the WNW motion of the Philippine Sea Plate exerts the most substantial impact on the study area,while the contributions from the Indian Plate and the Australian Plate remain secondary.
作者
许斌斌
张逸鹏
田晴映
杨雪
曾凡长
XU Binbin;ZHANG Yipeng;TIAN Qingying;YANG Xue;ZENG Fanchang(Guangdong Earthquake Agency,Guangzhou 510070,Guangdong,China;School of Earth Sciences and Engineering,Sun Yat-sen University,Zhuhai 519082,Guangdong,China;Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai 519082,Guangdong,China;Institute of Deep-sea Science and Engineering,Chinese Academy of Sciences,Sanya 572000,Hainan,China)
出处
《大地构造与成矿学》
北大核心
2025年第5期1036-1050,共15页
Geotectonica et Metallogenia
基金
广东省基础与应用基础研究基金项目(2023A1515110367)
南方海洋科学与工程广东省实验室(珠海)创新团队项目(99147-42080024)联合资助。
