俯冲带地震动特性及衰减规律初步研究

发布时间：2018-04-05 21:27

本文选题：俯冲带　切入点：南海海域　出处：《中国地震局工程力学研究所》2015年硕士论文

【摘要】：随着我国南海不断开发和建设,海洋工程的抗震问题日益受到重视。我国南海地区濒临俯冲带且该地带地震活动频繁。俯冲带地震动参数的估计需要了解其地震动的特性,本文研究围绕俯冲带地震动特性及其衰减规律展开,主要工作如下:1.介绍了国内外俯冲带地震动的研究现状及存在的问题。总结了我国南海海域地震的基本信息、俯冲带位置、该区域地震活动性及震源深度特点:俯冲带板缘地震发生过6.0级至8.0级的较大地震,而俯冲带板内地震以小于6.0级的中小震居多,南海开发建设需考虑俯冲带地震的影响。2..利用智利8.2级俯冲带板缘地震和日本俯冲带板缘、板内地震的实际地震动数据,对不同地区俯冲带地震动参数进行了比较和分析。对比结果表明:两次不同区域俯冲带地震的傅里叶谱存在较明显差异,日本地震的卓越频率比智利的值小;反应谱长周期差异较明显,日本地震的反应谱幅值要比智利的幅值大。通过比较相近震级下俯冲带板缘、板内地震和大陆地壳地震峰值加速度(PGA)随距离变化关系的趋势,结果表明:同一地区俯冲带板缘地震要比地壳地震衰减得慢,俯冲带板内地震要比地壳地震动衰减得快;俯冲带板缘地震的地震动小于浅地壳地震,小于俯冲带板内地震。俯冲带地震存在地区差异性。3.利用点源模型模拟了南海海域俯冲带板内地震动,并比较了不同深度的海水对海底地震动特性的影响。结果表明海底水平向地震动几乎不受海水介质的影响。根据南海俯冲带特性,采用有限断层法,模拟了较大震级下俯冲带板缘地震的基岩场地地震动并与日本的实际数据进行比较,模拟结果与实际数据在变化趋势上有一定相似性,表明模拟的俯冲带地震动符合实际。4.基于数值模拟地震动建立了典型俯冲带板缘地震的峰值加速度和加速度反应谱的衰减关系(基岩场地)。对PGA随距离变化的关系与我国现有陆域中强震模型及台湾地区的俯冲带衰减模型进行了比较,结果表明:数值模拟的地震动及拟合结果与实际数据模型有一定相似性。
[Abstract]:With the continuous development and construction of the South China Sea, the seismic problem of marine engineering has been paid more and more attention.The South China Sea is near the subduction zone and seismicity is frequent in this area.The estimation of ground motion parameters in subduction zone needs to know the characteristics of ground motion. In this paper, the characteristics and attenuation of ground motion in subduction zone are studied. The main work is as follows: 1.The research status and problems of subduction zone ground motion at home and abroad are introduced.This paper summarizes the basic information of earthquakes in the South China Sea, the location of the subduction zone, the seismicity of the region and the characteristics of the focal depth: a large earthquake of magnitude 6.0 to 8.0 occurred in the plate margin of the subduction zone.The small earthquakes with M < 6.0 in the subduction zone are the main ones. The development and construction of the South China Sea need to consider the influence of the subduction zone earthquakes.The seismic parameters of subduction zones in different regions are compared and analyzed by using the actual ground motion data of the plate margin earthquake of Chile M = 8.2 subduction zone and the plate edge and intraplate earthquake of Japan subduction zone.The results show that there are obvious differences in Fourier spectra between the two subduction zone earthquakes in different regions, the excellent frequency of earthquakes in Japan is smaller than that in Chile, and the long period difference in response spectrum is obvious.The amplitude of the response spectrum of the Japanese earthquake is larger than that of Chile.By comparing the relationship between the plate margin of the subduction zone with similar magnitude, the intraplate earthquake and the peak acceleration of the continental crust earthquake with the distance, the results show that the earthquake in the plate edge of the subduction zone in the same area attenuates more slowly than the crustal earthquake.The seismic attenuation of subduction zone is faster than that of crustal ground motion, and the ground motion of plate edge earthquake in subduction zone is smaller than that of shallow crust earthquake and subduction zone.Regional difference of earthquake in subduction zone.The point source model is used to simulate the subduction zone plate in the South China Sea, and the effects of sea water at different depths on the characteristics of sea floor motion are compared.The results show that the horizontal ground motion is almost independent of the seawater medium.According to the characteristics of the subduction zone in the South China Sea, finite fault method is used to simulate the ground motion of the bedrock site of the subduction zone with a larger magnitude and to compare with the actual data of Japan. The simulation results are similar to the actual data in the trend of variation.It shows that the simulated subduction zone ground motion accords with the actual .4.Based on the numerical simulation of ground motion, the attenuation relationship of peak acceleration and acceleration response spectrum of plate edge earthquake in typical subduction zone is established (bedrock site).The relationship between the variation of PGA and distance is compared with the existing models of moderate and strong earthquakes in the land area of China and the attenuation model of subduction zone in Taiwan. The results show that the simulated ground motion and fitting results are similar to the actual data models.
【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】：P315.9

【相似文献】