Calculating the two-dimensional magnetotelluric Jacobian in finite elements using reciprocity   总被引：6，自引：0，他引：6  

Patricia Pastana de Lugão  Philip E. Wannamaker 《Geophysical Journal International》1996,127(3):806-810

To speed up the calculation of the field Jacobian for 2-D magnetoteliuric inversion using finite elements, the principle of electromagnetic reciprocity is applied. The governing relationship for the Jacobian of the field along strike is obtained by differentiating the Helmholtz equation with respect to the resistivity of each region in the finite-element mesh. The result is a similar Helmholtz equation for the Jacobian, with new sources distributed over all nodes within the parameter medium. However, according to the principle of electromagnetic reciprocity, the roles of sources and receivers are interchangeable. Utilizing reciprocity, the field values obtained from the original forward problem and for new unit sources imposed at the receivers are then utilized in the calculation of the Jacobian by simple multiplication and summation with finite-element terms at each rectangle in the mesh. For the auxiliary (across-strike) fields, the Jacobian terms are obtained by solving source vectors loaded with parabola coefficients used in the approximation to Maxwell's equations. Jacobian terms for the apparent resistivity ( p _a), the impedance phase (φ) and the vertical magnetic field ( K _zy) are then calculated utilizing the parallel- and auxiliary-field Jacobians. Comparison of Jacobian values obtained from reciprocity calculations and by differencing two forward solutions show that the reciprocity method is accurate and can be used to decrease the number of calculations required to obtain sensitivities by one to two orders of magnitude.  相似文献   

区域经济联系定量分析初探：以上海与苏锡常地区经济联系为例   总被引：49，自引：2，他引：49  

王德忠  庄仁兴 《地理科学》1996,16(1):51-57

针对目前区域联合日益广泛和经济联系量化研究不足的现状，在联系强度等方面提出一些新概念；阐述了经济联系量化指标的选取，建立了经济联系定量分析模型。  相似文献   

极化分析研究及其在波场分离中的应用     

葛勇  韩立国  韩文明  孔玲君  顾贤明 《吉林大学学报(地球科学版)》1996,(1)

不同的波在空间的质点运动轨迹和极化方向是不同的，利用三分量或二分量记录，在特定的以ｔ０为中心，长为Ｎ△ｔ的滑动时窗中计算出描述波的质点运动轨迹和极化方向的特征参数。利用这些参数可以设计出合适的极化滤波函数，保留那些满足特定要求的质点运动，而衰减那些不满足设计要求的质点运动，利用某些算子可以把弹性波分解成Ｐ波和ＳＶ波，而且衰减面波；利用另外一些算子可以把Ｐ波和ＳＶ波衰减而使面波增强。这些算子甚至可以在嗓音和信号具有相同频率的情况下，成功地提高信嗓比。  相似文献   

频率域位场快速正则化反演界面和物性分布     

张贵宾  申宁华 《吉林大学学报(地球科学版)》1996,(4)

从理论与模型算例两方面对一种以Ｐａｒｋｅｒ公式为基础的频率域位场反演方法做了进一步深入研究。表明它是一种能够更有效地引入低通滤波因子的迭代方法。与改进的正则化稳定因子相结合，提出新的快速正则化反演方法。除了将其用于反演求解均质界面以外，它也被推广至变物性的界面反演以及物性反演  相似文献   

含油气盆地构造样式研究中几个问题的讨论   总被引：6，自引：0，他引：6  

王燮培  严俊君 《地质科技情报》1996,15(4):51-56

对我国含油气盆地构造样式研究中存在的一些主要问题进行了讨论。包括：关于构造样式的确切含义及类型的划分，由于对构造样式概念理解的不一致，导致了构造样式类型划分的混乱；构造样式的鉴别，往往由于过分强调了某些单一“鉴定标志”而忽略了总体变形特征，从而导致对构造变形机理的错误判断；中国含油气盆地的构造反转问题。  相似文献   

间歇侧移式的裂陷与递进跳跃式的反转：以阜新煤盆地为例   总被引：6，自引：0，他引：6  

王桂梁  马杏垣  荆惠林  云武  王大庆  谭海樵  李海玉 《高校地质学报》1996,(3)

位于闾山背斜隆起核部西侧的阜新断陷盆地从早白垩世义县组晚期开始，在东西两侧盆缘的Ｆ″１、Ｆ２断层所、围限的地堑内接受了义县组上部中性火山岩的堆积。火山喷发停止后，九佛堂组的大陆碎屑岩建造仍在Ｆ″１和Ｆ２断层之间的地堑内充填。九佛堂裂陷期之后该区地壳掀斜隆升，盆地南侧的义县地区开始反转抬升而不再接受沉积，西缘的Ｆ２断层也停止活动。到沙海组充填时盆地已演化为受Ｆ″１断层控制的、东断西超的半地堑盆地；沙海期裂陷终止后Ｆ″１断层停止活动，阜新组裂陷是在向东移的Ｆ′１盆缘断层控制下半地堑内发育的。阜新期裂陷结束后盆地又发生了一次跳跃式的反转，许多正断层发育成上逆下正的复合断层，并出现正花状构造。中白垩世孙家湾组的沉陷进一步向东侧移，形成了以Ｆ１断层为盆缘断层的半地堑；孙家湾期后发生本区最强烈的整体反转、隆升和褶断，结束了盆地的演化历史。阜新盆地间歇侧移式的裂陷与递进跳跃式的反转为盆地反转建立一个新的构造模式  相似文献   

The effects of pre-existing normal faults on thrust ramp development: An example from the northern Apennines,Italy     

E. Tavarnelli 《International Journal of Earth Sciences》1996,85(2):363-371

The Umbria-Marche foreland fold-and-thrust belt in the northern Apennines of Italy provides excellent evidence to test the hypothesis of synsedimentary-structural control on thrust ramp development. This orogenic belt consists of platform and pelagic carbonates, Late Triassic to Miocene in age, whose deposition was controlled by significant synsedimentary extension. Normal faulting, mainly active from Jurassic through Late Cretaceous-Paleogene time, resulted in significant lateral thickness variability within the related stratigraphic sequences. By Late Miocene time the sedimentary cover was detached from the underlying basement and was deformed by east-verging folds and west-dipping thrusts. Two restored balanced cross sections through the southernmost part of the belt show a coincidence between the early synsedimentary normal faults and the late thrust fault ramps. These evidences suggest that synsedimentary tectonic structures, such as faults and the related lithological lateral changes, can be regarded as mechanically important controlling factors in the process of thrust ramp development during positive tectonic inversion processes.  相似文献   

The transition from passive to active margin tectonics: a case study from the zone of Samedan (eastern Switzerland)     

M. R. Handy 《International Journal of Earth Sciences》1996,85(4):832-851

The Zone of Samedan is part of a fossil, early Mesozoic rift system originally situated in the distal, Lower Austro-Alpine domain of the Adriatic passive continental margin. An early Mesozoic configuration of asymmetrical rift basins bounded by relative structural highs compartmentalized Late Cretaceous active margin tectonics; Jurassic half-grabens were folded into arcuate synclines, whereas relative structural highs engendered thin, imbricated thrust sheets. West-directed thrusting and folding initiated at the surface and continued to depths favoring mylonitization under lower greenschist-facies conditions. At this time Liguria-Piemontese ophiolites were accreted to Lower Austro-Alpine units directly underlying the Zone of Samedan. Late Cretaceous orogenic collapse of the Adriatic active margin involved the reactivation of west-directed thrusts as low-angle, top-to-the-east, normal faults. These faults accommodated extensional uplift of Liguria-Piemontese ophiolites and Lower Austro-Alpine units beneath and within the Zone of Samedan. During Paleogene collision, some Late Cretaceous faults in the Zone of Samedan were reactivated under lower anchizonal conditions as north-directed thrusts. The latter stages of this early Tertiary thickening were transitional to brittle, high-angle normal faulting associated with top-to-the-east extension and spreading above the warm, uplifting Lepontine dome.  相似文献   

二维TIM中的传播矩阵与面波相速度     

阎贫  张中杰 《物探化探计算技术》1996,18(2):108-112

本文利用横向各向同性介质（ＴＩＭ）中的传播矩阵和面波形成条件，导出了面波波慢度方程。对瑞利波给出了各向同性及横向各向同性弹性介质中其相速度的解析解；对于勒夫波，给出了横向各向同性介质中的波慢度方程。  相似文献   

论广义逆矩阵阶数增大的递推算法     

蔡宗熹  蔡越虹 《物探化探计算技术》1996,18(2):113-117

本文针对加拿大地球物理学家ＥｄｏＮｇｌａｎｄ教授提出的问题，对Ｍ—Ｐ广义逆矩阵的递推算法进行了探分论述探讨的初步结果和对Ｇｒｅｖｉｌｌｅ递推算法的扩充。文中对算法的扩充给出严格的证明。  相似文献