中国地震海啸危险性分析

发布时间：2018-06-12 20:12

本文选题：地震海啸 + 局地海啸　；参考：《中国地震局工程力学研究所》2015年硕士论文

【摘要】：自古以来,中国沿海区域人口聚集,经济发达,交通便利,但相比于内陆,沿海区域有遭受海啸袭击的危险。近年来,沿海地区的海啸危险性分析工作已逐步开展,大都采用确定性分析方法给出了定性结果。采用概率性分析方法进行定量评估的工作还开展较少,主要原因是概率性海啸危险性分析(PTHA)关键步骤和环节还需完善,关键问题还需得到有效解决。因此,本文围绕PTHA关键参数确定、PTHA关键方法完善、PTHA参数敏感性分析三方面内容开展研究,最终编制我国地震海啸危险性图集。主要工作如下:(1)PTHA关键参数确定。在总结了常用的几种震级与断层长度、宽度和滑移量的经验关系基础上,通过比较它们的适用震级范围、适用地区范围以及使用现状,并且比较经验关系与近年发生的几次破坏性海啸的真实震源参数,确定了Papazachos等的针对逆冲断层经验公式较适合于我国局地和区域地震海啸源的震源参数估计;以局地潜在海啸源的震级上限作为其最危险案例进行数值模拟,分析海啸波对我国沿海地区的最大影响,给出了各局地海啸源对沿海地区的有效影响范围,以确定各局地海啸源的数值模拟计算范围。(2)PTHA关键方法完善。选取广东大亚湾3个场点,采用传统PTHA方法计算各场点对于不同海啸波高的超越概率,以示例揭示传统PTHA方法存在以下不足:震级分档的不连续性引起目标场点海啸波高分布的离散性;未考虑各潜在海啸源内地震发生位置的空间随机性;不能合理考虑PTHA结果的不确定性。针对这些问题提出了一种基于蒙特卡洛技术的PTHA方法,针对各潜在海啸源,对震级和震中位置进行多次随机采样,以此替代传统PTHA方法中震级分档环节。最后采用新方法计算了上述3个场点的不同海啸波高的超越概率,对比采用传统PTHA方法的计算结果说明新方法可以较好地完善传统方法存在的不足之处。(3)PTHA参数敏感性分析。以中国南海为研究对象,以马尼拉海沟俯冲区为潜在震源区,选取常用的SRTM、ETOPO、GEBCO三种水深数据,研究不同数据源的水深数据差异性以及数据自身误差对于地震海啸数值模拟的敏感性。结果表明在开阔的外海海域,不同数据源之间的水深数据差异对于海啸数值模拟的影响可忽略;水深数据自身误差对于数值模拟的海啸波幅值影响不明显,但对于其相位存在一定影响。得到如下结论:在大网格(低精度)计算环境下,海洋水深数据对于海啸波高数值模拟的敏感性是较轻微的,目前开放的水深数据可满足海啸传播数值模拟的需要。(4)编制我国地震海啸危险性图。采用本文提出的基于蒙特卡洛技术的PTHA方法,对我国东南沿海地区沿海岸线1480个场点进行PTHA计算,数值模拟了2个区域潜在海啸源和8个局地潜在海啸源的640个海啸案例,得到了这些场点的海啸波高分布。最终绘制了东南沿海地区海啸波高1m、2m、3m、4m、5m以1年、10年、50年、100年为周期的超越概率分布图以及波高1m、2m、3m、4m、5m的重现期分布图。
[Abstract]:Since ancient times, the population of the coastal areas of China has gathered, developed and convenient, but compared to the inland, the coastal area has the danger of the tsunami. In recent years, the tsunami hazard analysis work in the coastal areas has been gradually carried out, and most of the qualitative results are given by the deterministic analysis method. The main reason is that the key steps and links of the probabilistic tsunami hazard analysis (PTHA) need to be improved and the key problems still need to be effectively solved. Therefore, this paper focuses on the key parameters of PTHA, the improvement of the key PTHA methods, the sensitivity analysis of PTHA parameters, and the final compilation of the earthquake and tsunami in China. The main work is as follows: (1) the determination of the key parameters of PTHA. On the basis of summarizing the empirical relations between several commonly used magnitudes, the length of the fault, the width and the slip amount, by comparing their applicable magnitude range, the application of the area and the current situation, and the real relationship with several destructive tsunamis occurring in recent years. The real seismic source parameters determine the estimation of the source parameters of the empirical formula for the thrust fault, such as Papazachos, which is more suitable for the local and regional seismic tsunami sources in our country. The upper limit of the magnitude of the local potential tsunami source is used as the most dangerous case to simulate the maximum impact of the tsunami wave on the coastal areas of our country, and the local tsunamis are given. The effective range of the source to the coastal area is to determine the numerical simulation range of the local tsunami sources. (2) the key method of PTHA is perfect. The 3 sites in Dayawan, Guangdong, and the traditional PTHA method are used to calculate the transcendental probability of the different tsunami wave heights by the traditional method, and the following shortcomings of the traditional PTHA method are revealed. Continuity causes the dispersion of the height distribution of the tsunami wave in the target field; it does not consider the spatial randomness of the location of the earthquake in each potential tsunami source; the uncertainty of the PTHA results can not be considered reasonably. A PTHA method based on Monte Carlo technology is proposed for these problems, and the magnitude and location of the epicentre are more for each potential tsunami source. Sub random sampling is used to replace the magnitude division of the traditional PTHA method. Finally, a new method is used to calculate the transcendental probability of the different tsunami wave heights of the above 3 sites. Compared with the traditional PTHA method, the new method can better improve the shortcomings of the traditional methods. (3) the sensitivity analysis of PTHA parameters. The South China Sea is the research object, taking the Manila trench subduction area as the potential source area, selecting three kinds of water depth data of common SRTM, ETOPO and GEBCO, to study the difference of water depth data from different data sources and the sensitivity of data self error to seismic tsunami numerical simulation. The results show that water between different data sources is in open sea area. The influence of deep data difference on the tsunami numerical simulation can be neglected; the self error of water depth data has no obvious influence on the amplitude of the numerical simulation, but it has a certain influence on its phase. The following conclusion is drawn: under the large grid (low precision) computing environment, the sea depth data is less sensitive to the tsunami wave height numerical simulation. At present, the open water depth data can meet the needs of the numerical simulation of tsunami propagation. (4) compile the seismic and tsunami hazard map of our country. By using the PTHA method based on Monte Carlo technology proposed in this paper, the PTHA calculation is carried out along the coastline of the southeast coastal areas of China, and the potential tsunami sources and 8 local areas in 2 regions are numerically simulated. The 640 tsunami cases of potential tsunami source have obtained the distribution of tsunami wave height in these sites. Finally, we draw the map of the transcendental probability distribution of the tsunami wave height 1m, 2m, 3M, 4m, 5m for 1, 10, 50, 100 years in the southeast coastal region, as well as the heavy current distribution map of the wave height 1m, 2m, 3M, 4m, 5m.
【学位授予单位】：中国地震局工程力学研究所
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P731.25

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