再论各向异性介质转换波地震学,第一部分:理论     

Xiangyang Li  Jianxin Yuan British Geological Survey  West Mains Road  Edinburgh EH LA  UK. Formerly at British Geological Survey  now at PGS Inc.  Richmond Avenue  Suite  Houston  TX  USA. 《应用地球物理》2005,2(1)

我们业已研发了计算各向异性、非均质介质中P- SV转换波(C-波)的转换点和旅行时的新理论。据此 可以利用诸如相似性分析、迪克斯模型建模、克契 霍夫求和等常规方法来完成各向异性的处理和各向 异性处理,并使各向异性的处理成为可能。这里将 我们的新发展分作两部分来介绍。第一部分为理 论,第二部分为对速度分析和参数计算的应用。第 一部分理论包括转换点的计算和动校正的分析。  相似文献   

Converted-wave seismology in anisotropic media revisited,Part I: Basic theory     

Xiangyang Li  Jianxin Yuan 《应用地球物理》2005,2(1):26-40

We have developed new basic theories for calculating the conversion point and the travel time of the P-SV converted wave (C-wave) in anisotropic, inhomogeneous media. This enables the use of conventional procedures such as semblance analysis, Dix-type model building and Kirchhoff summation, to implement anisotropic processing, and makes anisotropic processing affordable. Here we present these new developments in two parts: basic theory and application to velocity analysis and parameter estimation. This part deals with the basic theory, including both conversion-point calculation and moveout analysis. Existing equations for calculating the PS-wave (C-wave) conversion point in layered media with vertical transverse isotropy (VTI) are strictly limited to offsets about half the reflector depth (an offset-depth ratio, xlz, of 0.5), and those for calculating the C-wave traveltimes are limited to offsets equal to the reflector depth (x/z=l.0). In contrast, the new equations for calculating the conversion-point extend into offsets about three-times the reflector depth (x/z=3.0), those for calculating the C-wave traveltimes extend into offsets twice the reflector depth (x/z=2.0). With the improved accuracy, the equations can help in C-wave data processing and parameter estimation in anisotropic, inhomogeneous media. This work is funded by the Edinburgh Anisotropy Project (EAP) of the British Geological Survey. First author: Xiangyang Li, Mr. Li is currently a professorial research seismologist (Grade 6) and technical director of the Edinburgh Anisotropy Project in the British Geological Survey. He also holds a honorary professorship in multicomponent seismology at the School of Geosciences, University of Edinburgh. He received his BSc(1982) in Geophysics from Changchun Geological Institute, China, an MSc (1984) in applied geophysics from East China Petroleum Institute (now known as the China University of Petroleum), and a PhD (1992) in seismology from the University of Edinburgh. During 1984–1987, he worked as a lecturer with the East China Petroleum Institute. Since 1991, he has been employed by the British Geological Survey. His research interests include seismic anisotropy and multicomponent seismology.  相似文献   

金龙——丘岭金矿床成矿流体的储运规律及区域找金方向     

刘新会 刘爽李渊  魏宽义 《地质找矿论丛》2005,20(8):10-14

金龙山——丘岭金矿区含金矿源为层上泥盆统南羊山组和下石炭统袁家沟组。组成含金矿源层岩石为高频互层的细碎屑岩-碳酸盐岩，其中细砂岩、粉砂岩、碳酸盐岩含成矿流体物性较好．页岩、板岩含成矿流体物性较差，构成屏蔽层。金鸡岭Ⅰ级复式向斜控制着金、砷、锑等异常范围；松枣Ⅱ级复式背斜控制着金的矿化带；金龙山-丘岭金矿Ⅲ级背斜控制着金的矿（化）体；镇安——板岩镇断裂的次级断裂是金矿化体的容矿有利位置。在成矿过程中，构造变形与成矿流体的形成、运移及储集密切相关。其规律是：①原生构造导致成矿流体的初次聚集。②第一期构造变形导致成矿流体的聚集。③第二期构造变形导致成矿流体运移及金矿床形成。此期变形是金的主要成矿期。④第三期构造变形使成矿流体进一步聚集和金矿体的富集。⑤第四期构造变形是石英方解石脉的形成时期。总结出矿床形成模式。据此提出了在4种不同的构造部位找金的方向。  相似文献   

渭北东部奥陶系岩溶地下水环境同位素特征分     

何渊 李亮黄金廷  范基姣 《地下水》2005,27(6):454-456

本文通过对渭北东部岩溶地下水环境同位素组成特征的研究，分析了大气降水、地表水、地下水三者之间的转化关系，并对研究区岩溶地下水的形成进行了初步探讨，认为大气降水是研究区岩溶地下水的补给源，地表水与地下水之间存在水力联系，地表水对地下水的补给占补给水源的74.3％。西部岩溶裸露区为岩溶水的直接补给区，其周边浅埋区为岩溶水的间接补给区，东南部的岩溶中-深埋区为岩溶水的径流排泄区。  相似文献   

滑坡监测的新方法——PMP测量方法     

孙园  李大心 《中国地质灾害与防治学报》2005,16(B12):15-18

文章从国内外滑坡灾害、滑坡灾害的危害及现有滑坡监测方法等方面，论述了滑坡灾害带来的危害性，从而验证了滑坡监测的重要性。但目前现行的滑坡监测手段各有不足之处。针对这种情况，提出了新的测量方法改进其不足之处。位相测量剖面术的测量原理是将LCD投影仪安装于滑坡体上，在滑坡体外稳定地带放置监测系统，CCD光束中心垂直于滑坡体位移方向，监测系统由望远镜头和CCD组成，CCD输出的视频信号进入计算机。通过软件对图像进行处理，绘制出滑坡整体的三维面貌，并计算出滑动的距离，从而有效的观测滑坡体的运动过程。  相似文献   

Analysis of the environmental sensitivities of a typical dynamic epikarst system at the Nongla monitoring site, Guangxi, China   总被引：6，自引：0，他引：6  

Zhang Cheng  Yuan Daoxian  Cao Jianhua 《Environmental Geology》2005,47(5):615-619

Nongla, a typical karst dynamic system (KDS) monitoring site, is located at Nongla Village, Mashan County, Guangxi, China. The data from a Greenspan CTDP300 multichannel data logger indicates that the KDS is highly sensitive to environmental changes. Multi-day and diurnal physico-chemical composition of epikarst spring water is quite different under different climatic conditions. During a day with no rainfall, water temperature and air temperature have similar variations. Electrical conductivity (EC) has good positive correlation with pH value and water temperature. During rainstorms, the physico-chemical composition of the spring water is initially strongly effected by dilution, pH and EC drop rapidly. However, half to one hour later, EC returns to normal and the CO₂ effects will be the dominant physical effect. This is due to the high fissure rates and high permeability in the epikarst zone. Dilution effects were observed during the entire rainstorm event,whereas, it only acts during the earliest period of light rain. Therefore, it is necessary to examine the water–rock–CO₂ combination as a whole system to explain the hydrochemical behavior of epikarst processes.  相似文献   

浓硫酸钠水溶液中的离子对          下载免费PDF全文

刘元会  房春晖 《盐湖研究》2005,13(4):42-46

不同浓度的Na2SO4水溶液的拉曼光谱显示了SO42-的四个拉曼活性带:980 cm-1处的SO42-的对称伸缩振动模式v1带,1 106 cm-1处的反对称伸缩振动模式v3带,448 cm-1处的变形振动模式v2带和617 cm-1处的变形振动模式v4带。482 cm-1处的肩膀峰是由于NaSO4-离子对的形成对448 cm-1的v2带的影响而形成的SO42-的一个新的振动峰。浓Na2SO4水溶液中,水共享离子对[Na+.H2O.SO42-]-是主要的离子对物种。随着Na2SO4水溶液浓度的增加,Na+和SO42-的相互作用增强,NaSO4-离子对所占的摩尔分数增加。  相似文献   

Validating the ability of the discontinuous deformation analysis method to model normal P‐wave propagation across rock fractures          下载免费PDF全文

Wenjun Gong  Yunsheng Wang  Youjun Ning  Yonghong Luo  Yujie Wang 《国际地质力学数值与分析法杂志》2017,41(10):1267-1282

The effects of fractures on wave propagation problems are increasingly abstracting the attention of scholars and engineers in rock engineering field. This study aims to fully validate the ability of discontinuous deformation analysis (DDA) to model normal P‐wave propagation across rock fractures. The effects of a single fracture and multiple parallel fractures are all tested. The results indicate that DDA can accurately reflect the fracture effects, including the fractures stiffness, the fracture spacing and the fracture number, and the effects of incident wave frequency on one‐dimensional P‐wave propagation problems. Thus, DDA is able to deal well with normal incident P‐wave propagation problems. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

A tree‐ring width based drought reconstruction for southeastern China: links to Pacific Ocean climate variability          下载免费PDF全文

Feng Chen  Shulong Yu  Yujiang Yuan  Huiqin Wang  Mary Gagen 《Boreas: An International Journal of Quaternary Research》2016,45(2):335-346

We present a drought reconstruction for southeastern China based on a tree‐ring width chronology of Cryptomeria fortunei developed from two sampling sites in central Fujian. A reconstruction of July–February drought variability, spanning AD 1855–2011, was developed by calibrating total tree‐ring width data with the self‐calibrating Palmer drought severity index (scPDSI). The reconstruction was verified against an independent data set, and accounts for 36% of the actual scPDSI variance during the period 1955–2011. Relatively dry intervals were reconstructed between AD 1859–1880, 1899–1911, 1927–1933, 1946–1959, 1964–1970 and 1987–1997. Relatively wet conditions prevailed during 1855–1858, 1881–1898, 1912–1926, 1934–1945, 1960–1963, 1971–1986 and 1998–2011. Comparisons between our scPDSI reconstruction and a moisture‐sensitive tree‐ring width record from Vietnam revealed consistencies between the two data sets, suggesting similar drought regimes. Spectral peaks of 2.2–6.4 years may be indicative of El Niño‐Southern Oscillation (ENSO) activity, as also suggested by the significant correlations with sea surface temperatures (SSTs) in the eastern equatorial and southeastern Pacific Ocean and an extreme event analysis. The analysis of links between our scPDSI reconstruction and the large‐scale regional climatic variation shows that there is a relationship between regional drought variation and East Asian summer monsoon (EASM) intensity.  相似文献   

Simulation of earthquake-induced hazards of falling exterior non-structural components and its application to emergency shelter design     

Zhen Xu  Xinzheng Lu  Hong Guan  Yuan Tian  Aizhu Ren 《Natural Hazards》2016,80(2):935-950

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