本文選題：構(gòu)造應(yīng)力場 + GPS　； 參考：《長安大學(xué)》2015年碩士論文

【摘要】：在眾多自然災(zāi)害中,地震災(zāi)害以其突發(fā)性和不可預(yù)測性對人類生活影響最大。通過地震學(xué)家長期對地震的研究發(fā)現(xiàn),一般認為它由地球內(nèi)部的巖體受到內(nèi)部應(yīng)力影響,致使巖體突然斷裂錯動而產(chǎn)生,最終造成地表不同程度的形變和破壞。隨著空間測量技術(shù)的發(fā)展,利用GPS技術(shù)能夠精確獲取地殼動態(tài)形變和構(gòu)造應(yīng)力場變化,結(jié)合地質(zhì)和地球物理資料,探求強震孕育、發(fā)生及發(fā)展規(guī)律,從而最大限度的降低地震災(zāi)害。青藏高原東緣地質(zhì)構(gòu)造復(fù)雜,活動強烈。本文以青藏高原東緣作為研究區(qū)域,利用多期GPS觀測數(shù)據(jù),從地殼形變和塊體斷裂的角度分析了地震引發(fā)的塊體應(yīng)變場及構(gòu)造應(yīng)力場變化特征,探求其活動斷裂的運動方式;與此同時,利用邊界元法對川滇地塊構(gòu)造應(yīng)力場進行計算,模擬區(qū)域地震演化特征,結(jié)合該區(qū)域地質(zhì)背景資料,探求汶川地震誘發(fā)因素及其驅(qū)動力源。論文主要工作與成果如下:1.以GPS數(shù)據(jù)為基礎(chǔ),利用整體旋轉(zhuǎn)線性應(yīng)變法和多面函數(shù)法分別模擬了青藏高原東緣地殼形變及區(qū)域應(yīng)力場變化特征,研究塊體運動趨勢及內(nèi)部應(yīng)變場變化,闡述了構(gòu)造應(yīng)力場特征與地質(zhì)結(jié)構(gòu)分布和地震活動的關(guān)系,兩種方法體現(xiàn)出較好的一致性。2.青藏高原東緣構(gòu)造應(yīng)力場以南北向壓應(yīng)力為主,東西向拉張力為輔,印度板塊向北推壓和歐亞板塊向南推進迄今仍起主控作用。其位移場總體上由南向北呈逐漸減小趨勢,主應(yīng)力主要在四川、云南區(qū)域高度集中。同期的強震也主要發(fā)生在應(yīng)力高度集中、剪切應(yīng)變值變化范圍大和具有深大斷層區(qū)域。3.基于邊界元算法驗證了地殼內(nèi)部介質(zhì)參數(shù)對區(qū)域構(gòu)造應(yīng)力場結(jié)果的影響。研究表明:在力邊界條件不變的情況下,改變泊松比值將會影響位移場和構(gòu)造應(yīng)力場的結(jié)果;改變彈性模量值,僅改變位移場結(jié)果,而不改變應(yīng)力場結(jié)果。彈性模量大,位移值小,應(yīng)變量也減小,應(yīng)力值變大,反之也成立。4.利用邊界單元數(shù)值模擬法對川滇地區(qū)地殼形變和深部動力機制進行了分析,探求龍門山斷裂帶深部構(gòu)造特征與汶川地震的誘發(fā)因素及驅(qū)動力源。認為其主要來自印澳板塊與歐亞大陸碰撞及向北擠壓、青藏高原向東運移延伸遭遇華南板塊阻擋,應(yīng)力場及能量高度集中導(dǎo)致地殼表面發(fā)生破裂、內(nèi)部斷裂發(fā)生錯動而造成的。
[Abstract]:Among many natural disasters, earthquake disaster has the greatest impact on human life because of its sudden and unpredictability. Through the seismologists' long-term research on earthquake, it is generally believed that it is caused by the internal stress of the rock mass inside the earth, resulting in the sudden fracture and dislocation of the rock mass, resulting in different degrees of deformation and destruction of the surface of the earth. With the development of space survey technology, the dynamic crustal deformation and tectonic stress field changes can be accurately obtained by using GPS technology. Combined with geological and geophysical data, the law of strong earthquake preparation, occurrence and development can be explored. In order to minimize the earthquake disaster. The eastern margin of Qinghai-Xizang Plateau is characterized by complex geological structure and strong activity. Taking the eastern margin of the Qinghai-Xizang Plateau as the study area and using the multi-period GPS observation data, the variation characteristics of the earthquake induced block strain field and tectonic stress field are analyzed from the point of view of crustal deformation and block faults, and the movement mode of its active faults is explored. At the same time, the boundary element method is used to calculate the tectonic stress field of Sichuan-Yunnan block, to simulate the evolution characteristics of regional earthquakes, and to explore the induced factors and driving force sources of Wenchuan earthquake combined with the regional geological background data. The main work and results are as follows: 1. Based on GPS data, the variation characteristics of crustal deformation and regional stress field in the eastern margin of Qinghai-Xizang Plateau are simulated by using the integral rotation linear strain method and the multi-plane function method, respectively, and the trend of block movement and the variation of internal strain field are studied. The relationship between the characteristics of tectonic stress field and the distribution of geological structure and seismic activity is expounded. The tectonic stress field in the eastern margin of the Qinghai-Xizang Plateau is dominated by the south-north compressive stress supplemented by the east-west tension. The thrust of the Indian plate to the north and the Eurasian plate to the south still play a dominant role so far. The displacement field decreases gradually from south to north, and the principal stress is mainly concentrated in Sichuan and Yunnan regions. The strong earthquakes in the same period also mainly occurred in the high stress concentration, the range of shear strain change was large and the area with deep fault was .3. Based on the boundary element algorithm, the influence of the medium parameters in the crust on the results of the regional tectonic stress field is verified. The results show that changing Poisson ratio will affect the results of displacement field and tectonic stress field when the force boundary condition is invariant, and change the elastic modulus value, only change the displacement field result, but not change the stress field result. The elastic modulus is large, the displacement value is small, the strain variable is also reduced, and the stress value is increased. The crustal deformation and deep dynamic mechanism in Sichuan-Yunnan area are analyzed by using boundary element numerical simulation method, and the deep structural characteristics of Longmenshan fault zone and the inducing factors and driving force sources of Wenchuan earthquake are explored. It is considered that the collision between the Indo-Australian plate and the Eurasian continent and the northward compression, the eastward migration of the Qinghai-Xizang Plateau is blocked by the South China plate, and the stress field and the high concentration of energy lead to the rupture of the crustal surface and the dislocation of the internal fracture.
【學(xué)位授予單位】：長安大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P228.4;P315.727

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