摘要
1994年台湾浅滩M_(S)7.3地震,是近几个世纪以来南海东北部发生的最大破坏性地震之一,且有明确的海啸波记录。本研究基于潮位站记录、震后报道和相关文献资料,通过多组海啸数值模拟,约束该事件的地震参数和破裂特征(震级、断层几何、滑移分布等),并分析海啸波的传播演化规律及其可能的灾害影响。模拟结果显示1994年台湾浅滩地震触发的海啸影响南到澳门地区,北至温州上千公里的海岸线以及几乎整个台湾岛西海岸。距离震源最近的福建东山岛-厦门一带受海啸影响最大,最大波高可达0.25 m,其次是汕头–泉州一带(0.15~0.20 m)。由于震中位置距离台湾省较近,海啸波在震后10 min到达高雄沿海,30 min传播到福建省东山岛一带,3 h到达香港地区、澳门地区沿海,5 h内几乎覆盖整个华南沿海东岸和台湾省西岸。通过分析最大海啸波幅分布和典型站点时序曲线,获得一些新的认识:(1)1994年台湾浅滩地震的震级可能接近M_(W)6.9,可能的震源机制以高角度正断地震为主;(2)断层关键参数和滑移分布对海啸触发有重要的影响,开展更精确海啸模拟和灾害评估需要更加明确这些参数;(3)板内地震海啸到达华南沿岸地区的时间更短,其伴生的海平面急剧振荡等现象,在当前华南沿海海洋经济高速发展时期的潜在灾害损失大。目前我们对南海东北部板内地震源的认知严重不足,该区域潜在海啸灾害评估的不确定性较大。因此,需要对大陆架内活动断层的精细几何结构和地震活动性开展地球物理联合调查,为开展海洋地质灾害评估与制定沿海防灾减灾措施提供依据。
The 1994 Taiwan Strait Earthquake was one of the largest earthquakes that have ever occurred in the northeast South China Sea(SCS)in recent centuries.It also triggered a localized tsunami that was clearly recorded by the Dongshan tidal gauge in China.Based on tsunami records,post-event reports,and relevant literature,this study constrained key fault parameters and rupture characteristics(e.g.,magnitude,fault geometry,and slip distribution)via a series of numerical tsunami simulations,and analyzed the propagation,evolution,and potential disaster impacts of tsunami waves in the northeast SCS.The simulation results show that the tsunami generated by the 1994 Taiwan Strait Earthquake affected the coastline of South China from Wenzhou in the north to Macao City in the south,covering almost the entire western coast of Taiwan Island.Near-source regions,such as Dongshan Island and Xiamen City,experienced the most significant tsunami impact,with the maximum tsunami wave height reaching to 0.25 m.The coasts of Shantou City and Quanzhou City were affected by tsunami waves with heights between 0.15 and 0.20 meters.Due to the proximity of the epicenter to the coastline,the tsunami waves reached the coast of Kaohsiung City within 10 minutes after the earthquake and reached Dongshan Island within half an hour,arrived on the coasts of Hong Kong region and Macao region about 3 hours after the earthquake,and covered almost the entire eastern coast of South China and the western coast of Taiwan province within 5 hours after the earthquake.By analyzing the distribution of maximum tsunami wave amplitudes and tsunami wave curves of virtual tidal gauges,we thus drawed several new conclusions:(1)The magnitude of the 1994 Taiwan Strait earthquake may be close to Mw 6.9,and the possible focal mechanism is a high-angle normal fault earthquake;(2)Key fault parameters and slip distribution have significant impacts on tsunami generation.More precise tsunami simulations and disaster assessments require a clearer understanding of these parameters;(3)Tsunamis generated by intraplate earthquakes in the northeast SCS reach the coast of South China in a very short time,and associated phenomena,such as rapid sea-level oscillations,could lead to enormous potential losses,especially during the current period of rapid development of marine economy in South China.Currently,our understanding of intraplate seismic sources in the northeast SCS is very limited,and the uncertainty associated with potential tsunami hazard assessments in this region remains high.Therefore,it is necessary to conduct comprehensive marine geophysical surveys to map active fault traces,geometric structures,and seismogenic characteristics in the northeast SCS,providing a scientific basis for marine geohazard assessments and the formulation of coastal disaster prevention and mitigation measures.
作者
章紫喻
李琳琳
王培涛
许斌斌
高义
李志刚
王伟涛
ZHANG Ziyu;LI Linlin;WANG Peitao;XU Binbin;GAO Yi;LI Zhigang;WANG Weitao(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;National Marine Environmental Forecasting Center,Ministry of Natural Resources,Beijing 100081,China;Guangdong Earthquake Agency,Guangzhou 510070,Guangdong,China)
出处
《大地构造与成矿学》
北大核心
2025年第5期1101-1116,共16页
Geotectonica et Metallogenia
基金
国家重点研发计划项目(2023YFC3008600)
广东省“珠江人才计划”引进创新创业团队项目(2021ZT09H399)
南方海洋科学与工程广东省实验室(珠海)创新团队项目(311023002)联合资助。
关键词
板内地震
地震海啸
数值模拟
南海东北部大陆架
intraplate earthquake
earthquake tsunami
numerical simulation
northeast South China Sea
