本文選題：背景噪聲 + 紫坪鋪水庫��； 參考：《中國地震局地震預測研究所》2015年碩士論文

【摘要】：中國是世界上水庫數(shù)量最多的國家。水庫在發(fā)揮重要作用的同時,也引發(fā)了一系列的地質(zhì)災害問題。中國又是世界上水庫地震多發(fā)的國家之一。水庫誘發(fā)地震不僅可能直接破壞水庫大壩,還有可能引發(fā)嚴重的次生災害。尤其是近些年,我國在地震多發(fā)的川滇地區(qū)建設(shè)了大量高壩、大庫容的梯級電站。水庫地震時有發(fā)生,大型水庫的水庫地震問題引起了地震學者的高度重視。汶川地震后,由于紫坪鋪水庫的特殊時空關(guān)系,更是引發(fā)廣泛關(guān)注。本文利用2005年1月1日至2008年1月1日紫坪鋪臺網(wǎng)及YZP臺連續(xù)波形資料,對紫坪鋪水庫庫區(qū)地下介質(zhì)展開研究。研究時間段包含了紫坪鋪三次大規(guī)模蓄水和兩次泄水的過程。具體研究方法為:利用地震背景噪聲互相關(guān)提取臺站對間經(jīng)驗格林函數(shù)(CCFs);經(jīng)過較長時間的疊加獲得參考格林函數(shù)(REF);通過比較經(jīng)驗格林函數(shù)(CCFs)與參考格林函數(shù)(REF)來測定介質(zhì)相對波速的變化。根據(jù)得出的結(jié)果,本文分別對三次蓄水及兩次泄水過程進行了分析,討論了不同階段影響相對波速變化的主要因素,追蹤了水在不同深度介質(zhì)中的滲透過程。同時,本文還分別對庫區(qū)地下介質(zhì)相對波速變化與庫區(qū)地震頻度、深度的關(guān)系進行了分析。主要研究結(jié)論如下:1、紫坪鋪水庫在大規(guī)模蓄水前,庫區(qū)地下介質(zhì)的相對波速變化與水位變化沒有明顯的相關(guān)性,而在后面的水位加卸載過程中,表現(xiàn)出了明顯的負相關(guān)性,即水位升高,相對波速降低,水位降低,相對波速升高。分析認為,第一次蓄水及泄水時,壓力是導致介質(zhì)相對波速變化的主要因素,而滲透作用只影響到了2km以內(nèi)的淺層介質(zhì)。后兩次蓄水及泄水時,滲透作用與壓力共同作用。在第二次蓄水至最高點時,滲透作用影響至4km左右的斷層,在第二次泄水至最低點時,滲透作用已影響至8km左右的斷層。最后一次蓄水時,三個周期的相對波速變化都與水位變化非常的一致,具有較高的互相關(guān)系數(shù)。此時水已滲透至深度為8km以下的斷層。2、通過庫區(qū)地下介質(zhì)相對波速變化與庫區(qū)地震頻度變化的關(guān)系分析,認為在三個水位快速上升的月份,對應著地震頻次的相應增加,而同時對應著介質(zhì)相對波速由0附近迅速降低的過程。3、通過庫區(qū)地下介質(zhì)相對波速變化與庫區(qū)地震深度變化的關(guān)系分析,認為蓄水后大部分小震震源深度都明顯集中在5km左右,這與本文分析的滲透作用過程相一致。本文的研究結(jié)論有利于深化對庫區(qū)地下結(jié)構(gòu)、狀態(tài)和動力學過程的認識。同時,結(jié)合水庫地震頻次及深度的分析發(fā)現(xiàn),對于地下淺層介質(zhì)相對波速連續(xù)變化的研究,可能為水庫誘發(fā)地震的判斷及預測提供幫助,具有十分重要的意義。
[Abstract]:China has the largest number of reservoirs in the world. Reservoir plays an important role, but also triggered a series of geological disasters. China is also one of the countries in the world prone to reservoir earthquakes. Reservoir induced earthquakes may not only directly destroy reservoir dams, but also cause serious secondary disasters. Especially in recent years, a large number of cascaded hydropower stations with high dams and large reservoirs have been built in the earthquake-prone Sichuan-Yunnan region. Reservoir earthquakes occur from time to time, and earthquake problems in large reservoirs have attracted great attention of seismologists. After the Wenchuan earthquake, due to the special time-space relationship of Zipingpu reservoir, it aroused widespread concern. Based on the continuous waveform data of Zipingpu network and YZP station from January 1, 2005 to January 1, 2008, the underground media of Zipingpu reservoir area are studied. The research period includes three large-scale water storage and two drainage processes in Zipingpu. The specific research methods are as follows: the cross-correlation of seismic background noise is used to extract the empirical Green's function between stations and stations; the reference Green's function is obtained after a long period of superposition; and by comparing the empirical Green's function with the reference Green's function, the reference Green's function is obtained by comparing the empirical Green's function (CCFs) with the reference Green's function (REFF). The variation of the relative wave velocity of the medium was measured. According to the results obtained, the three water storage and two discharge processes are analyzed, and the main factors affecting the relative wave velocity at different stages are discussed, and the permeation process of water in different depth medium is tracked. At the same time, the relationship between the variation of relative wave velocity of underground media and seismic frequency and depth in the reservoir area is also analyzed in this paper. The main conclusions are as follows: before the large-scale storage of water in Zipingpu Reservoir, there is no obvious correlation between the variation of relative wave velocity and the change of water level in the underground media in the reservoir area, but in the process of loading and unloading of the later water level, there is an obvious negative correlation. That is, the water level rises, the relative wave velocity decreases, the water level decreases, and the relative wave velocity increases. It is concluded that the pressure is the main factor leading to the variation of the relative wave velocity of the medium during the first water storage and discharge while the permeation only affects the shallow media within the 2km. In the latter two times of water storage and drainage, osmotic action and pressure act together. At the second water storage to the highest point, the permeability affects the fault around 4km, and at the second discharge to the lowest point, the permeability affects the fault around 8km. At the last impoundment, the variation of relative wave velocity in the three periods is very consistent with the change of water level, and has a high correlation number. At this time, the water has penetrated to the fault below the depth of 8km. Through the analysis of the relation between the relative wave velocity change of underground media and the seismic frequency change in the reservoir area, it is concluded that the corresponding increase of earthquake frequency is corresponding to the three months when the water level rises rapidly. At the same time, corresponding to the process that the relative wave velocity of the medium decreases rapidly from 0 to 0, through the analysis of the relationship between the variation of the relative wave velocity of the underground medium in the reservoir area and the variation of the seismic depth in the reservoir area, it is considered that most of the focal depths of the small earthquakes after the storage of water are obviously concentrated around 5km. This is consistent with the osmotic process analyzed in this paper. The conclusion of this paper is helpful to deepen the understanding of underground structure, state and dynamic process of reservoir area. At the same time, combined with the analysis of seismic frequency and depth of reservoir, it is found that the study on the continuous variation of relative wave velocity in shallow underground media may be of great significance for the judgment and prediction of reservoir induced earthquakes.
【學位授予單位】：中國地震局地震預測研究所
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：P315.728

【參考文獻】

相關(guān)期刊論文 前2條

1 王惠琳;張曉東;周龍泉;徐曉楓;楊志高;盧顯;李智蓉;;紫坪鋪水庫區(qū)域地殼Q_s成像及其與滲透關(guān)系研究[J];地球物理學報;2012年02期

2 陳鈏,李麗;地震科學的幾個發(fā)展趨勢[J];國際地震動態(tài);2003年01期

相關(guān)碩士學位論文 前1條

1 盧顯;紫坪鋪水庫區(qū)域地震初步研究[D];中國地震局地震預測研究所;2010年

，

本文編號：1794250