An inverse method for underwater bottom topography by using SAR imagery   总被引：2，自引：2，他引：0  

Jin Yaqiu  Zhang Wei 《海洋学报(英文版)》2000,19(4):53-62

I~IOXThe image technology of the synthetic aperture radar (SAR) is one of most important advances in spaceberne microwave remote sensing (Larson et al., 1976). It has extensive application in the ocean remote sensing, such as inversion of the sea subdue winds and currentS, reconstruction of underwater hatom topography and so on. Owing tO the high conductivity of sea water, an electromagnetic wave actually cannot penetrate into the sea water, with extremely smallPenetration depth (abbot 1 c…  相似文献   

用合成孔径雷达图像反演浅海水下地形的一种方法   总被引：2，自引：0，他引：2  

张巍  金亚秋  沈一帆 《海洋学报》2000,22(6):40-46

海流与海底地形的相互作用导致了海表面的粗糙起伏,从而引起对海面观测的雷达散射截面的变化。在浅海海流速度垂直分布廓线为均匀的假定下,由流体连续性方程和驰豫时间近似下流体力学弱相互作用的理论,已证明雷达散射截面的空间变化正比于海流方向上海流速度变化的梯度。研究了合成孔径雷达(SAR)对海面的观测图像在无槽道信息和海流方向预知条件下,提出用散射系数的二维相关函数确定海流方向。在海流速度和方向已知条件下,推导了由雷达散射截面的空间变化迭推反演浅海水下地形的公式,并研究了航天飞机SIR-CSAR在我香港特区海域的二维图像反演浅海水下地形的应用。  相似文献   

Shear sense inversion in the Hilti mantle section (Oman ophiolite) and active mantle uprise     

Michibayashi  K.  Gerbert-Gaillard  L.  Nicolas  A. 《Marine Geophysical Researches》2000,21(3-4):259-268

Structural analyses in the well-exposed Hilti mantle section in the Oman ophiolite suggest a model of forceful horizontal flow in the uppermost mantle at the edge of a diapir below a oceanic spreading center. Detailed structural mapping, focussed on high-T deformation (i.e., asthenospheric flow), revealed a gently undulated flat structure with a uniform east-west flow direction. When it is related to the N–S to NNW–SSE trending, vertical sheeted dike complex located to the east, this mantle flow is parallel to the spreading direction. Because the Moho is so flat lying, a large dunite occurrence at the south-western region is possibly ascribed to the Moho Transition Zone. Kinematic analysis shows that the shear direction generally changes from top-to-the west in the upper level, to top-to-the east in the lower level with respect to the Moho. This shear sense inversion is explained by a model of forceful flow due to an active mantle uprise and it is not compatible with a passive mantle uprise. In the plan section, the boundary of the shear sense inversion is subparallel to the flow direction and subperpendicular to the spreading axis. In cross section, the boundary appears to occur at various depths in the range of 200 m to 500 m. It shows that the active mantle uprise in the diapir center resulted in a channelled horizontal flow.  相似文献   

Simultaneous waveform inversion for three-dimensional Earth structure and earthquake source parameters considering a wide range of modal coupling     

Tatsuhiko Hara  & Robert J. Geller 《Geophysical Journal International》2000,142(2):539-550

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Artificial neural network inversion of magnetotelluric data in terms of three-dimensional earth macroparameters   总被引：7，自引：0，他引：7  

Vjacheslav Spichak  & Irina Popova 《Geophysical Journal International》2000,142(1):15-26

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The Neftegorsk (Sakhalin Island) 1995 earthquake: a rare interplate event     

S. Arefiev  E. Rogozhin  R. Tatevossian  L. Rivera  A. Cisternas 《Geophysical Journal International》2000,143(3):595-607

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Approximate retrieval of the point source in anisotropic media: numerical modelling by indirect parametrization of the source   总被引：1，自引：0，他引：1  

Jan &#;&#;´lený  Václav Vavry&#;uk 《Geophysical Journal International》2000,143(3):700-708

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SEQUENTIAL STIFFNESS DESIGN FOR SEISMIC DRIFT RANGES OF A SHEAR BUILDING–PILE–SOIL SYSTEM     

T. NAKAMURA  I. TAKEWAKI  Y. ASAOKA 《地震工程与结构动力学》1996,25(12):1405-1420

A shear building supported by a prescribed pile–soil system is subjected to bedrock earthquake input. A new design procedure is presented for generating a sequence of stiffness designs satisfying the constraints on interstorey drifts. The mean peak interstorey drifts of the shear building subjected to a set of spectrum-compatible ground motions at the bedrock are evaluated by a modal combination rule. Tuning of the fundamental natural period of a shear building with a fixed base with that of a shear beam ground results in a non-monotonic sequence of stiffness designs with respect to a ground stiffness parameter and previous approaches cannot be applied to such a problem. This difficulty in finding such a non-monotonic sequence is overcome by utilizing the ground stiffness parameter and the superstructure stiffness parameter alternately in multiple design phases and by developing a new multi-phase perturbation technique. Fundamental characteristics of this sequence of stiffness designs and the effect of ground stiffnesses on the design of the shear building are disclosed. It is further shown that the stiffness contour method is also useful for the design procedure such that a scattering effect in the estimates of ground stiffnesses is taken into account. The usefulness of the proposed procedure of sequential stiffness design and contour line method is demonstrated through several sequential design examples.  相似文献   

岫岩5.4级地震序列主应力变化特征研究     

兰从欣  刘杰  马士振  武敏捷  苗春兰 《地震》2006,26(2):73-82

根据1999年岫岩地震序列的活动特点, 将其划分为前震、 余震密集、 余震平静、 余震衰减4个时段, 利用收集整理的1999年6月至2000年9月间该序列中161次2.5级以上地震的震源机制解和Gephart的应力反演方法, 研究了震源区各时段内构造应力场的总体特征和时序变化特征。 结果表明, 序列的主压应力方向与华北地区的构造应力场基本一致, 而且最大主压应力的空间取向经历了主震前相对稳定—主震后分散—最大余震前相对稳定—最大余震后分散的全过程。 该结果对主震和最大余震的预测具有一定的参考价值。  相似文献   

位移测量反演分析的解算模型与应用     

潘国荣 《大地测量与地球动力学》2006,26(2):75-78

利用现场位移测量资料反演分析是进行洞室围岩稳定分析和了解岩体介质中洞室的力学性状与设计参数的一种新手段。阐述了位移测量反演分析的基本思路、解算模型、成果检验等,并用计算实例说明了其有效性。  相似文献