潜在地震海啸源区强震危险性估计及在海啸风险分析中的应用

发布时间：2018-02-13 01:54

本文关键词： 潜在地震海啸源强震重现水平广义极值分布琉球海沟俯冲带海啸风险分析　出处：《防灾科技学院》2016年硕士论文　论文类型：学位论文

【摘要】：地震海啸危险性分析是当前国内外学者比较关注的问题之一,潜在地震海啸源区强震危险性估计包括震级上限和强震重现水平的估计,它是地震海啸危险性分析的基础内容。我国东南沿海地区存在着遭受一定规模的破坏性地震海啸袭击的风险,开展东南沿海地区潜在地震海啸源区的强震危险性估计是十分必要的。根据对强震危险性的估计结果可以得到区域内的震级上限和未来一定年限内的强震重现水平,这些估计结果可以为工程设防以及海啸淹没图和人员疏散图的绘制提供参考。本文从强震危险性估计,案例区域的选择与参数估计,估计结果在海啸风险分析中的初步应用三个方面来开展工作。(1)强震危险性估计参考前人在震级上限方面的相关研究,将广义极值理论应用到在潜在地震海啸源区震级上限和强震重现水平的估计。在时间步长的选取中,考虑到地震活动的平静期和活跃期,在潜源区划分上考虑到所选区域的地质构造背景,这样得到的结果更加符合实际的地震活动特征。由于估计结果存在一定的不确定性,文中采用协方差矩阵的方法,分析震级上限和强震重现水平的估计结果不确定性,获得其一定置信水平下的置信区间。(2)案例区域的选择与参数估计选定琉球海沟俯冲带(22°N-32.5°N,120.5°E-133°E)作为案例研究区域。采用USGS(United States Geological Survey)网站的地震记录对所选区域地震活动性进行了初步分析,大致估计该区域的地震活动周期,以此为时间步长,选取1910-2010年内每10年的最大震级组成极值样本。估计了基于广义极值分布模型的参数并对该模型进行了拟合诊断,得到琉球海沟俯冲带的震级上限在置信度为95%的置信区间为8.4±0.37,未来30年,50年和100年内的强震重现水平为7.8?0.54,8.0?0.48和8.1±0.42。(3)海啸风险的初步分析介绍了基于概率统计方法的海啸危险性分析的基本原理和步骤。根据强震危险性估计结果,计算断层位错,结合前人研究成果,采用COMCOT模式进行了海啸数值模拟,获得整个模拟计算区域最大海啸波高数据,据其绘制出特定场点海啸波高随时间的变化曲线图和模拟计算区域最大海啸波高分布图。
[Abstract]:Earthquake and tsunami risk analysis is one of the problems that scholars at home and abroad pay close attention to at present. The estimation of strong earthquake risk in potential earthquake and tsunami source area includes the upper limit of earthquake magnitude and the estimation of recurrence level of strong earthquake. It is the basic content of earthquake and tsunami risk analysis. The southeast coastal area of China has the risk of being hit by destructive earthquake and tsunami on a certain scale. It is necessary to estimate the strong earthquake risk in the source areas of potential earthquakes and tsunamis in the southeast coastal areas. Based on the estimation results of strong earthquake risk, the upper limit of magnitude and the recurrence level of strong earthquakes in the future years can be obtained. These results can be used as a reference for engineering fortification and the drawing of tsunami inundation map and evacuation map. In this paper, we estimate the risk of strong earthquake, the selection of case area and the estimation of parameters. Preliminary Application of the estimated results in Tsunami risk Analysis to carry out work. 1) strong earthquake risk estimation refers to previous studies on magnitude upper limit. The generalized extreme value theory is applied to estimate the upper limit of magnitude and the recurrence level of strong earthquakes in the source area of potential earthquakes and tsunamis. In the selection of time step, the quiet and active periods of seismic activity are taken into account. The geological tectonic background of the selected area is taken into account in the division of the potential source area, so that the obtained results are more in line with the actual seismic characteristics. Because of the uncertainty of the estimated results, the covariance matrix method is used in this paper. The uncertainty of the estimation results of the upper limit of magnitude and the recurrence level of strong earthquakes is analyzed. The selection and parameter estimation of the case area under a certain confidence level are selected as the case study area of the Ryukyu trench subduction zone 22 掳N-32.5 掳Nao 120.5 掳E-133 掳E). Seismicity of selected area is studied by using seismic records of the USGS(United States Geological survey website. A preliminary analysis was carried out. The period of seismic activity in this region is estimated roughly, and the time step is taken as the time step. The maximum magnitude of every 10 years in 1910-2010 is selected as an extreme value sample. The parameters based on the generalized extreme value distribution model are estimated and the fitting diagnosis of the model is carried out. The upper limit of magnitude of the Ryukyu trench subduction zone is 8. 4 卤0. 37 at the confidence interval of 95%. The recurrence level of strong earthquakes in the next 30 years, 50 years and 100 years is 7.8? 0.54,8.0? The basic principles and steps of tsunami risk analysis based on probabilistic statistical method are introduced. According to the results of strong earthquake risk estimation, fault dislocations are calculated and combined with previous research results. The COMCOT model is used to simulate the tsunami wave, and the maximum tsunami wave height data in the whole simulated area are obtained. According to the data, the curve of tsunami wave height variation with time at a specific site and the maximum tsunami wave height distribution map in the simulated calculation area are drawn.
【学位授予单位】：防灾科技学院
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P731.25

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