溫?fù)P茂++許才軍++何平++江國(guó)焰++劉洋

摘 要：為了更好地研究重力場(chǎng)對(duì)地殼形變、活動(dòng)斷層、地震等動(dòng)力學(xué)過(guò)程的時(shí)變響應(yīng)，需要建立動(dòng)態(tài)地殼形變模型，研究重力、形變與地震波數(shù)據(jù)聯(lián)合反演活動(dòng)斷層參數(shù)的相關(guān)理論及方法，進(jìn)行活動(dòng)斷層潛在地震的危險(xiǎn)性評(píng)估，探討強(qiáng)震發(fā)生的動(dòng)力學(xué)背景。該報(bào)告主要介紹兩個(gè)方面的研究?jī)?nèi)容：一方面是如何表述反演數(shù)據(jù)中多源數(shù)據(jù)的權(quán)矩陣，通過(guò)引入虛擬觀測(cè)方程將斷層滑動(dòng)的連續(xù)性約束一并納入觀察方程，采用Helmert方差分量估計(jì)確定各類觀測(cè)數(shù)據(jù)的權(quán)比，推導(dǎo)了相關(guān)理論公式。另一方面，利用InSAR和GPS資料提取了Iwaki和Kita-Ibarake兩個(gè)余震區(qū)典型余震的同震形變場(chǎng)，以及結(jié)合InSAR干涉圖形狀和方位向偏移量法對(duì)發(fā)震斷層的幾何參數(shù)進(jìn)行約束。在此基礎(chǔ)上，采用彈性半空間矩形位錯(cuò)模型對(duì)這兩個(gè)強(qiáng)余震的同震滑動(dòng)分布進(jìn)行反演，得到的最大滑動(dòng)量分別為3.28 m和0.98 m。最后利用余震的斷層作為接收斷層，計(jì)算了Mw 9.0 Tohoku-Oki靜態(tài)庫(kù)侖應(yīng)力對(duì)余震作用的大小，結(jié)果顯示Iwaki和Kita-Ibarake研究區(qū)的余震近似為純正斷層類型的淺源地震，靜態(tài)庫(kù)侖應(yīng)力在兩個(gè)研究區(qū)的最大值分別為1.1 MPa和0.7 MPa，表明Mw 9.0 Tohoku-Oki地震對(duì)研究區(qū)的余震觸發(fā)是有促進(jìn)作用的。

關(guān)鍵詞：多源數(shù)據(jù) 反演 活動(dòng)斷層 地震波數(shù)據(jù) 同震形變場(chǎng)

Abstract：In order to understand the time-dependent gravity response from crustal deformation， active fault， earthquakes and other dynamic processes， we need to estimate the kinematic crustal deformation model， to study theory and method of active fault parameters joint inversion from gravity， deformation and seismic data， to do the potential earthquake hazard assessment of active faults and to explore the dynamic background of strong earthquakes. This report focuses on the following two aspects： on one hand， we introduce the fault slip continuity constraint as a virtual observation function to observation functions， and determine the relative weight of various kinds of observation using Helmert variance component estimation. On the other hand， we derive the coseismic deformation of Iwaki and Kita-Ibarake aftershocks from InSAR and GPS data， and obtain the preliminary location of the fault traces combing InSAR deformation pattern with azimuth-offset measurements. The fault location and geometry of these two earthquakes are constrained by a rectangular dislocation model in a multilayered elastic half-space， which indicates that the maximum slips for the two earthquakes are 3.28 m and 0.98 m， respectively. The Coulomb stress changes are calculated for the faults following the 2011 Mw 9.0 Tohoku-Oki earthquake based on the modeled slip along the fault planes. The resulting Coulomb stress changes indicate that the stresses on the faults increased by up to 1.1 MPa and 0.7 MPa in the Iwaki and Kita-Ibarake regions， respectively， suggesting that the Tohoku-Oki earthquake triggered the two aftershocks， supporting the results of seismic tomography.

Key Words：Multi-source data；Inversion；Weight ratio；Dislocaiton model；Earthquake；InSAR

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