三峡大坝对川西地区地震活动影响的研究

发布时间：2018-04-26 00:35

  本文选题：三峡大坝 + 川西地震　； 参考：《电子科技大学》2014年硕士论文

【摘要】：三峡大坝自2003年开始蓄水至2006年正式竣工,规模巨大,举世瞩目。但三峡大坝库容巨大,可能会诱发地震,国内外许多学者都针对这一问题进行了探究,但这些研究都是针对库区的,而且大多是从地质学、地震学角度出发。本文利用数理方法从地震数据本身出发,从统计学角度对三峡大坝对远距离库区以外区域地震的影响展开研究,以川西为例,主要工作包含以下几个方面:1.研究、分析、归纳川西地震呈现的特征规律,有以下几点:(1)三峡水库建造后18年较之前18年川西地区的地震频次有大幅增长。(2)三峡大坝蓄水前川西地震的分布较为分散,低水位蓄水期时,地震主要分布在安宁河断裂带周围,少量分布在鲜水河断裂带附近,随着水位继续上升,地震开始向龙门山断裂带附近聚集,并呈现向安宁河断裂带靠近的趋势。(3)随蓄水水位上升,长江流域的地震向川西地区聚集。(4)三峡大坝在每个蓄水期的震源深度均值都比蓄水前小,高水位蓄水期间变化更明显。(5)三峡大坝高水位时地震释放的能量高于低水位时地震释放的能量。2.利用傅立叶变换技术从频域角度验证三峡大坝水位曲线与川西地震频次曲线变化趋势上的相似性,又从统计学角度利用二者的相关系数验证是否存在相关性,结论表明,两者之间确实存在某种程度上的相关性。3.从川西地区重力场变化角度对此相关性及上面发现的地震规律做出相应验证。伴随三峡水库蓄水和放水活动,川西地区重力场呈现正变化和负变化;水位上升初期,重力场变化不明显,随时间延长,重力场变化逐渐增大。所以水库水位变化影响川西地区重力场,而重力场动态变化能够反映地球内部物质变化和变形过程,并与地震有紧密联系。所以三峡大坝会通过影响川西重力场变化间接影响川西地震活动。4.最后结合三峡大坝自身,分析三峡大坝对川西地震活动产生影响的原因,得出结论——三峡大坝的建造在一定程度上对川西地震活动产生影响。
[Abstract]:The three Gorges Dam has been impounded since 2003 until its completion in 2006. But the reservoir capacity of the three Gorges Dam is huge, which may induce earthquakes. Many scholars at home and abroad have explored this problem, but these researches are aimed at the reservoir area, and most of them are from the point of view of geology and seismology. In this paper, the effect of the three Gorges Dam on earthquakes outside the remote reservoir area is studied from the point of view of statistics from the seismic data itself by mathematical method. Taking West Sichuan as an example, the main work includes the following several aspects: 1. Study, analysis and summary of the characteristics of the earthquake in western Sichuan, there are the following points: 1) after the three Gorges Reservoir was built, the earthquake frequency in the west of Sichuan increased significantly after 18 years compared with the previous 18 years. 2) the distribution of the earthquakes in the west of Sichuan before the three Gorges Dam impounding is relatively scattered. During the period of low water level storage, the earthquakes mainly distributed around the Anning River fault zone, and a few distributed near the Xianshuihe fault zone. As the water level continued to rise, the earthquake began to gather near the Longmenshan fault zone. There is a tendency of approaching to the Anning River fault zone. (3) with the water level rising, the earthquakes in the Yangtze River basin gather to the west of Sichuan. 4) the mean of the focal depth of the three Gorges Dam in each storage period is smaller than that before the water storage. The energy released by the three Gorges Dam at high water level is higher than that at low water level. The Fourier transform technique is used to verify the similarity between the water level curve of the three Gorges Dam and the seismic frequency curve in the west of Sichuan Province from the angle of frequency domain, and the correlation coefficient of the two curves is used to verify the correlation from the statistical point of view. There is a certain degree of correlation between the two. From the angle of variation of gravity field in western Sichuan, the correlation and the seismic law found above are verified. Along with the water storage and discharge activities of the three Gorges Reservoir, the gravity field in western Sichuan presents positive and negative changes, but at the initial stage of water level rise, the change of gravity field is not obvious, and the variation of gravity field increases with time. Therefore, the variation of reservoir water level affects the gravity field in western Sichuan, and the dynamic variation of gravity field can reflect the material change and deformation process in the earth's interior, and is closely related to earthquakes. Therefore, the three Gorges Dam will indirectly affect seismic activity. 4. 4 by influencing the variation of gravity field in western Sichuan. Finally, combined with the three Gorges Dam itself, the causes of the influence of the three Gorges Dam on the seismic activity in western Sichuan are analyzed, and the conclusion is drawn that the construction of the three Gorges Dam has an effect on the seismic activity in the west of Sichuan to a certain extent.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV697.24
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本文编号：1803711