地震研究

耦合震级、震源深度和滑动角不确定性效应的地震海啸危险性估计

刘哲^1,2,任鲁川^3

(1.河北红山巨厚沉积与地震灾害国家野外科学观测研究站,河北邢台 054000; 2.唐山地震监测中心站,河北唐山 063000; 3.防灾科技学院,河北三河 065200)

Estimation of the Risk of Earthquake-induced Tsunami by Coupling Uncertainty of Magnitude,Focal Depth and Slip Angle

LIU Zhe^1,2,REN Luchuan³

(1.Hebei Hongshan National Observatory on Thick Sediments and Seismic Hazards,Xingtai 054000,Hebei,China)(2.Tangshan Earthquake Monitor Center,Tangshan 063000,Hebei,China)(3.Institute of Disaster Prevention,Sanhe 065200,Hebei,China)

Keywords：GRACE; the dislocation model; gravity gradient; the Bengkulu,Indonesia M_W8.4 earthquake

DOI: 10.20015/j.cnki.ISSN1000-0666.2024.0026

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参考文献

选取中国东南沿海地区6个近岸场点,以马尼拉海沟俯冲带和琉球海沟俯冲带作为潜在地震海啸源区,采用广义极值地震活动性模型和广义帕累托地震活动性模型分析震级不确定性特征,通过统计震源深度的优势分布和拟合滑动角分布函数,耦合震级、震源深度和滑动角不确定性效应,得到两个俯冲带对6个场点未来30 a、50 a、100 a海啸波高超过0.4 m的地震海啸危险性估计结果。结果表明:百年内舟山近海和宁德近海特定场点遭受地震海啸袭击风险较低,随着时间的推移,从位于厦门近海至香港近海、海口近海和高雄近海的特定场点,地震海啸危险性递增。

Firstly,we choose 6 sites—Zhoushan,Ningde,Xiamen,Hongkong,Haikou,and Gaoxiong in the southeastern coastal areas in China as the research samples.Then we suppose the Manila trench subduction zone and the Ryukyu trench subduction zone are the potential sources of the earthquake-induced tsunami.We estimate the uncertainty of the magnitude by the Generalized Extreme Value method and the Generalized Pareto Distribution.By probabilistic statistics,we get the predominant distribution of the focal depths of the potential earthquakes in these two subduction zones.By fitting the function of slip angle's distribution and by coupling the uncertainty of magnitude,focal depth,and slip angle,we estimate that the potential earthquakes in the Manila trench subduction zone and the Ryukyu trench subduction zone would induce tsunamis whose wave height exceeds 0.4 m at the 6 sites in next 30,50 and 100 years.

引言
1 地震海啸危险性估计原理与方法
2 强震地震活动性模型
3 算例
4 结论与讨论

表1 特定场点地理位置及水深<br/>Tab.1 Geographical location and water depth of the specific sites

表1 特定场点地理位置及水深
Tab.1 Geographical location and water depth of the specific sites

图1 海啸数值模拟区域和网格划分示意图(图中大矩形表示第一层网格,小矩形表示第二层网格)<br/>Fig.1 Sketch map of the tsunami numerical simulation area and meshing

图1 海啸数值模拟区域和网格划分示意图(图中大矩形表示第一层网格,小矩形表示第二层网格)
Fig.1 Sketch map of the tsunami numerical simulation area and meshing

表2 潜在地震海啸源震级分档<br/>Tab.2 Magnitude interval of the potential seismic tsunami source

表2 潜在地震海啸源震级分档
Tab.2 Magnitude interval of the potential seismic tsunami source

表3 马尼拉海沟俯冲带和琉球海沟俯冲带地震重现期、地震年发生率、重现水平估计方差<br/>Tab.3 Seismic return period and annual occurrence and estimate variance of return level in Manila trench subduction zone and Ryukyu trench subduction zone

表3 马尼拉海沟俯冲带和琉球海沟俯冲带地震重现期、地震年发生率、重现水平估计方差
Tab.3 Seismic return period and annual occurrence and estimate variance of return level in Manila trench subduction zone and Ryukyu trench subduction zone

表4 1900—2010年两个俯冲带MW≥6.0地震的震源深度<br/>Tab.4 The focal depth of MW≥6.0 earthquakes during 1900—2010

表4 1900—2010年两个俯冲带MW≥6.0地震的震源深度
Tab.4 The focal depth of MW≥6.0 earthquakes during 1900—2010

图2 1900—2010年马尼拉海沟俯冲带(a)和琉球海沟俯冲带(b)MW≥6.0地震的震源深度分布概率<br/>Fig.2 Distribution probability of the focal depth of the MW≥6.0 earthquakes in Manila trench subduction zone (a)and Ryukyu trench subduction zone(b)

图2 1900—2010年马尼拉海沟俯冲带(a)和琉球海沟俯冲带(b)MW≥6.0地震的震源深度分布概率
Fig.2 Distribution probability of the focal depth of the MW≥6.0 earthquakes in Manila trench subduction zone (a)and Ryukyu trench subduction zone(b)

图3 马尼拉海沟俯冲带(a)和琉球海沟俯冲带(b)滑动角分布频数<br/>Fig.3 Distribution probability of the slip angle in Marila trener subduction zone(a)and Ruyaku trench subductpon zone(b)

图3 马尼拉海沟俯冲带(a)和琉球海沟俯冲带(b)滑动角分布频数
Fig.3 Distribution probability of the slip angle in Marila trener subduction zone(a)and Ruyaku trench subductpon zone(b)

表5 滑动角分布概率密度函数<br/>Tab.5 Probability density of the slip angle

表5 滑动角分布概率密度函数
Tab.5 Probability density of the slip angle

表6 蒙特卡洛采样得到的马尼拉海沟俯冲带震源深度为15 km时的海啸数值模拟的参数样本<br/>Tab.6 Sample parameters of the tsunami numerical simulation by the Monte Carlo sampling with the focal depth 15 km in Manila trench subduction zone

表6 蒙特卡洛采样得到的马尼拉海沟俯冲带震源深度为15 km时的海啸数值模拟的参数样本
Tab.6 Sample parameters of the tsunami numerical simulation by the Monte Carlo sampling with the focal depth 15 km in Manila trench subduction zone

表7 蒙特卡洛采样得到的琉球海沟震源深度为20 km时的海啸数值模拟的参数样本<br/>Tab.7 Sample parameters of the tsunami numerical simulation by the Monte Carlo sampling with the focal depth 20 km in Ryukyu trench subduction zone

表7 蒙特卡洛采样得到的琉球海沟震源深度为20 km时的海啸数值模拟的参数样本
Tab.7 Sample parameters of the tsunami numerical simulation by the Monte Carlo sampling with the focal depth 20 km in Ryukyu trench subduction zone

表8 海啸数值模拟第二层网格区域范围<br/>Tab.8 Second layer range of the mesh grid in the tsunami numerical simulation area

表8 海啸数值模拟第二层网格区域范围
Tab.8 Second layer range of the mesh grid in the tsunami numerical simulation area

表9 马尼拉海沟俯冲带和琉球海沟俯冲带最大海啸波高分布的正态模型参数<br/>Tab.9 Parameters of the normal distribution for the maximum tsunami wave height in the Manila trench subduction zone and the Ryukyu trench subduction zone

表9 马尼拉海沟俯冲带和琉球海沟俯冲带最大海啸波高分布的正态模型参数
Tab.9 Parameters of the normal distribution for the maximum tsunami wave height in the Manila trench subduction zone and the Ryukyu trench subduction zone

表10 马尼拉海沟俯冲带和琉球海沟俯冲带6个场点的地震海啸平均年发生率<br/>Tab.10 Annual mean rate of the seismic tsunami recurrence of the specific sites in the Manila trench subduction zone and thd Ryukyu trench subduction zone

表10 马尼拉海沟俯冲带和琉球海沟俯冲带6个场点的地震海啸平均年发生率
Tab.10 Annual mean rate of the seismic tsunami recurrence of the specific sites in the Manila trench subduction zone and thd Ryukyu trench subduction zone