摘要
珠江三角洲位于南海北部沿海,是华南地区重要的经济枢纽,其地质稳定性对粤港澳大湾区城市群的安全与区域可持续发展具有重要意义。本研究聚焦于三角洲腹地西淋岗地区,通过综合野外地质调查与年代学分析,系统揭示了晚第四纪断裂活动特征及其灾害响应机制。研究表明:西淋岗断裂在约17 ka和15 ka分别经历了两次显著的活动事件,首次活动引发了山体滑坡并破坏了沉积序列,第二次活动则导致软沉积物变形(SSD),形成了液化喷砂、泄水构造等典型的震积标志。基于地质剖面分析与测年数据,进一步验证15 ka的SSD事件与古地震直接相关,推测震级约为6级,为区域地震活动历史提供了关键证据。研究发现,西淋岗断裂的晚第四纪正断层活动以地震振动诱发软沉积物液化及构造错动触发滑坡两种机制为特征;三角洲腹地第四纪断层活动性的分析进一步揭示了隐伏构造对区域稳定性的潜在威胁。研究成果为华南沿海断陷盆地的地震-沉积响应机制研究提供了新证据,同时为大湾区地质灾害风险评估、重大工程选址避让及城市防灾规划提供了科学依据,对提升区域地质安全保障能力具有重要的实践意义。
The Pearl River Delta(PRD),situated along the northern coast of the South China Sea,represents a key economic center in southern China,where geological stability is essential for the safety of the Guangdong-Hong Kong-Macao Greater Bay Area and the sustainable development of the region.This study focused on the Xilingang area within the PRD,and conducted a systematic investigation into the characteristics of Late Quaternary fault activity and related geological hazards through integrated field surveys and Quaternary dating techniques.The findings reveal two significant activation events of the Xilingang Fault occurring at approximately 17 ka and 15 ka.The first event triggered a landslide that disrupted sedimentary sequences,while the second event caused soft-sediment deformation(SSD),characterized by liquefaction features such as sand injections and water-escape structures.Based on geological profile analysis and chronological data,the 15 ka SSD event is confirmed to be directly linked to paleoseismic activity,with an estimated seismic magnitude of approximately M 6.This provides crucial evidence for reconstructing the region’s seismic history.The study shows that Late Quaternary normal faulting of the Xilingang Fault resulted in dual mechanisms:seismic vibrations leading to sediment liquefaction and tectonic displacement causing slope instability.Moreover,the activity of Quaternary faults in the PRD’s hinterland underscores the potential influence of concealed structures on regional stability.These results offer new perspectives on the seismic-sedimentary response mechanisms of coastal fault basins in South China and provide a scientific basis for geological hazard assessment,critical infrastructure planning,and urban disaster mitigation strategies in the Greater Bay Area,thus enhancing regional geological safety and resilience.
作者
陈震
卿展晖
黄屏
梁浩
林小明
张献河
李宏卫
许冠军
吴维盛
黄孝波
CHEN Zhen;QING Zhanhui;HUANG Ping;LIANG Hao;LIN Xiaoming;ZHANG Xianhe;LI Hongwei;XU Guanjun;WU Weisheng;HUANG Xiaobo(GDZD Institute on Deep-Earth Sciences Co.,Ltd.,Guangzhou 510275,Guangdong,China;Guangdong Provincial Key Laboratory of Geodynamics and Geohazards/School of Earth Sciences and Engineering,Sun Yat-sen University,Zhuhai 519082,Guangdong,China;Guangdong Geological Environment Monitoring Station,Guangzhou 510599,Guangdong,China;Geological Survey and Research Institute of Guangdong Province,Guangzhou 510080,Guangdong,China)
出处
《大地构造与成矿学》
北大核心
2025年第5期1062-1072,共11页
Geotectonica et Metallogenia
基金
国家重点研发计划项目(2023YFC3008600)
广东省城市地质资源环境监测数据集成项目(0877-24GZTP1ZC0133)
广东省国土资源保护与治理专项资金项目(2017201)
东莞市多要素城市地质调查项目(HT[2021]0203号)
广东省基础与应用基础研究基金项目(2023A1515011812)联合资助。
关键词
珠江三角洲
西淋岗
第四纪断层
软沉积物变形
古地震
Pearl River Delta
Xilingang
Quaternary fault
soft sediment deformation
paleoseismicity
