發(fā)布時(shí)間：2018-03-22 17:27

  本文選題：GRACE衛(wèi)星　切入點(diǎn)：黏彈球體位錯(cuò)理論　出處：《中國(guó)地震局地震預(yù)測(cè)研究所》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：地震導(dǎo)致的地殼變形是研究地球內(nèi)部構(gòu)造,地震孕育發(fā)生機(jī)理的重要研究方向。隨著現(xiàn)代大地測(cè)量技術(shù)的不斷發(fā)展,除了可以用GPS和InSAR觀測(cè)到震后地殼形變外,重力衛(wèi)星GRACE能夠觀測(cè)到特大的俯沖型地震引起的~300 km空間分辨率的長(zhǎng)波長(zhǎng)同震和震后重力變化。自2002年成功發(fā)射以來,GRACE衛(wèi)星已經(jīng)連續(xù)提供超過十年的全球重力場(chǎng)數(shù)據(jù),為研究震源機(jī)制、發(fā)震機(jī)理、地球內(nèi)部構(gòu)造、地震預(yù)測(cè)、斷層反演、大地測(cè)量結(jié)果解釋以及確定震源參數(shù)等提供了豐富的資料。對(duì)于震后變形機(jī)制解釋目前主要有黏彈性松弛,震后余滑、空隙流體回彈等理論。震后變形機(jī)制需要結(jié)合地震位錯(cuò)理論進(jìn)行解釋,Tanaka等(2006)提出的黏彈性球體位錯(cuò)理論可以同時(shí)考慮地球的可壓縮性和無限分層的影響,是目前最為完備的震后位錯(cuò)理論之一。本文的主要目的是研究利用GRACE衛(wèi)星數(shù)據(jù)提取蘇門答臘地震(Mw9.3)導(dǎo)致的同震和震后重力變化信號(hào),并結(jié)合Tanaka等(2006)的黏彈性球體位錯(cuò)理論對(duì)其進(jìn)行解析,為研究地球內(nèi)部構(gòu)造研究和地震孕育機(jī)理研究等提供支持。本文主要研究工作如下:1)GRACE Release05數(shù)據(jù)預(yù)處理方法的研究對(duì)CSR(Center for Space Research University of Texas)發(fā)布的GRACE Level02Rlease05重力場(chǎng)數(shù)據(jù)進(jìn)行去相關(guān)濾波處理,去除重力場(chǎng)球諧系數(shù)奇偶階次之間的相關(guān)誤差,削弱重力場(chǎng)空間分布中的南北條帶現(xiàn)象,并利用高斯平滑方法處理GRACE數(shù)據(jù)中的偶然誤差,不同的平滑半徑對(duì)平滑結(jié)果影響很大,平滑半徑需要根據(jù)研究區(qū)域大小慎重選取,建議結(jié)合去相關(guān)濾波和高斯平滑方法同時(shí)進(jìn)行處理。2)GRACE數(shù)據(jù)提取同震和震后重力信號(hào)的方法研究分別利用差分法和最小二乘擬合法提取了蘇門答臘地震(Mw9.3)同震重力變化空間分布,并結(jié)合彈性球體位錯(cuò)理論結(jié)果比較了兩種方法的優(yōu)劣:差分法較最小二乘方法能更好的提取地震重力信號(hào);然后利用差分法提取了蘇門答臘地震(Mw9.3)同震和震后七年的重力變化,結(jié)果顯示斷層兩側(cè)地幔黏度存在較大差異;此外,本文還提取了斷層兩側(cè)單點(diǎn)A(95.0°E,1.5°N)和B(97.0°E,7.0°N)地震前后重力場(chǎng)時(shí)間序列,分析了其時(shí)間序列特征。3)黏彈性球體位錯(cuò)理論研究了黏彈性球體位錯(cuò)理論的理論基礎(chǔ)和計(jì)算思路,給出北極任意斷層在任意點(diǎn)產(chǎn)生的震后變形(垂直位移和空間固定點(diǎn)重力變化)計(jì)算公式和在地球任意點(diǎn)任意斷層在地表任意點(diǎn)產(chǎn)生的震后變形計(jì)算公式。4)黏彈球體位錯(cuò)積分程序改進(jìn)指出黏彈球體位錯(cuò)積分程序計(jì)算近場(chǎng)變形誤差較大的缺陷,并利用Sun和Okubo(1998)的有限斷層積分方法對(duì)其改進(jìn),比較了兩種理論震源深度為10 km和32 km四種獨(dú)立震源垂直位移和重力變化格林函數(shù),二者基本一致;改進(jìn)后的程序模擬結(jié)果與彈性球體位錯(cuò)理論同震模擬結(jié)果垂直位移和重力變化平均差異分別為0.05%和0.03%,并分析了四種獨(dú)立震源在震源深度為32 km,地幔黏度為1×1018 Pa?s的0~0.7年和0~7年的重力變化格林函數(shù)。5)改進(jìn)后的黏彈性球體位錯(cuò)理論的應(yīng)用利用改進(jìn)后的黏彈性位錯(cuò)積分程序?qū)μK門答臘地震(Mw9.3)震后重力變化進(jìn)行模擬,并將其與GRACE觀測(cè)結(jié)果進(jìn)行比較,模擬結(jié)果與GRACE觀測(cè)結(jié)果在峰值空間分布和震后變化趨勢(shì)上基本一致。該地區(qū)地幔黏度存在明顯橫向差異,下盤區(qū)域地幔取內(nèi)黏度系數(shù)約為1×1018 Pa?s,上盤區(qū)域地幔黏度系數(shù)約為8×1018Pa?s。
[Abstract]:The earthquake caused the crustal deformation is the internal structure of the earth, an important research direction of earthquake occurrence mechanism. With the continuous development of modern geodetic techniques, except for GPS and InSAR observed postseismic crustal deformation, gravity satellites can be observed GRACE long wavelength ~300 km spatial resolution of large subduction earthquakes caused by the same after the earthquake, earthquake and gravity changes. Since 2002 the successful launch of the GRACE satellite has a continuous supply of global gravity field data of more than ten years, for the study of focal mechanism, earthquake mechanism, the internal structure of the earth, earthquake prediction, fault inversion, geodetic measurement interpretation and provides a wealth of information to determine the source parameters for post earthquake deformation mechanism. Explain the current mainly viscoelastic relaxation, afterslip, interstitial fluid rebound theory. After the deformation mechanism requires a combination of dislocation theory to explain Tana Ka (2006) proposed the theory of viscoelastic spherical dislocation can be considered at the same time the earth compressibility and infinite layered effect, is one of the most complete earthquake dislocation theory. The main purpose of this paper is to study the extraction of Sumatra earthquake GRACE satellite data (Mw9.3) caused by the coseismic and postseismic gravity change signal, and according to Tanaka (2006) of the viscoelastic spherical dislocation theory to analyze the mechanism of inoculation, provides support for the study of the internal structure of the earth and the earthquake. The main research work are as follows: 1) the number of GRACE Release05 according to the study of pretreatment methods on CSR (Center for Space Research University of Texas) GRACE Level02Rlease05 gravity field data released to the related filter, remove the gravitational field of spherical harmonic coefficients of correlation between parity order error, weakening the North South gravity field spatial distribution of strip in the present Like, and use the Gauss smoothing method to process error in GRACE data, different smoothing radius has great influence on the smoothing result, smoothing radius according to research area carefully selected, combining with correlation filtering and smoothing method to Gauss and.2) GRACE data extraction method of coseismic and postseismic gravity signal respectively by differential method and the least square fitting method to extract the Sumatra earthquake (Mw9.3) distribution of coseismic gravity changes in space, and combined with the elastic sphere dislocation theory results compares two methods: signal extraction of seismic gravity difference method can be better than the least squares method; then using difference method to extract the Sumatra earthquake (Mw9.3) with gravity change seven years after the earthquake and earthquake, results show that there is a big difference on both sides of the fault mantle viscosity; in addition, this paper also extracts on both sides of the fault point A (95 E, 1.5 N) and B (97 ~ E, 7 ~ N) before and after the earthquake gravity field time series analysis of the time sequence characteristics of.3) viscoelastic spherical dislocation theory to study the theoretical basis and calculation method of viscoelastic spherical dislocation theory, given any faults at any point in the Arctic earthquake (change of vertical displacement and deformation space fixed point gravity) calculation formula of.4 deformation formula and at any point at any point on the earth's surface of arbitrary fault earthquake) sticky dislocation process improvement that Pinball integral calculation near field deformation errors of the sticky Pinball dislocation integration process, and the use of Sun and Okubo (1998) improved finite integral method of fault the comparison of two kinds of theories, the focal depth of 10 km and 32 km four independent source vertical displacements and gravity changes of Green function, the two are basically the same; the improved simulation result and elastic dislocation theory with the ball 闇囨ā鎷熺粨鏋滃瀭鐩翠綅縐誨拰閲嶅姏鍙樺寲騫沖潎宸紓鍒嗗埆涓，

本文編號(hào)：1649648