商丹断裂构造特征及其演化     

王全庆 《地球科学与环境学报》1992,(1)

商丹断裂带是北秦岭加里东造山带与中秦岭海西造山带的分界断裂,由韧性剪切应变带、逆冲推覆构造带、地堑断陷带及其所夹持的岩块、岩片、构造岩、褶曲等多种地质体组合成复杂的断裂带。其演化历史至少经历晋宁期俯冲、加里东期碰撞、海西—印支期陆内俯冲、燕山期滑脱推覆和喜山期地堑断陷的复杂演化过程而形成今日所见的复杂断裂构造。  相似文献   

The optimum control of thruster system for dynamically positioned vessels     

C. C. Liang  W. H. Cheng 《Ocean Engineering》2004,31(1):97-110

An offshore vessel with a dynamic positioning system (DP system) needs fast response to produce thrust to counteract the environmental forces acting on it for the purpose of maintaining its position and heading as close as possible to the working position. Therefore, quick and effective modulation of the thrust is the problem to determine the thrust and the rotation angle of the thruster devices of the ship. This paper presents an effective optimum control for a thruster system, using the sequential quadratic method to achieve economical and effective modulation of the thrust and the direction of the thruster. An optimum control study of a 2280 tons DP coring vessel with five rotary azimuth thruster marine positioning is studied in detail, which can quickly and exactly estimate the thrusts and angles of direction of all the thrusters. The results can provide a valuable thruster system for a dynamically positioned vessel.  相似文献   

大地问题的截面椭圆弧长新解     

黄晓颖  边少锋 《海洋测绘》2007,27(1):21-23

分析了以前大地问题中截面椭圆弧长计算方法的缺点，在运用Mathematic的基础上，提出了在这一问题上的计算方便、过程简单的新方法，并用该方法进行了一个实例计算，效果良好。  相似文献   

基于GPS的短基线定向测量及精度分析     

崔建勇  杨力  任锴  张好 《测绘信息与工程》2008,33(2):12-14

介绍了利用GPS载波相位测量技术进行短基线定向的基本方法,推导了估计GPS短基线定向的精度公式,得到了对于边长400～700 m的基线可以达到±(1"～2")的方位精度.  相似文献   

Weak-contrast approximation of the elastic scattering matrix in anisotropic media     

Bjørn Ursin  Geir U. Haugen 《Pure and Applied Geophysics》1996,148(3-4):685-714

The plane-wave reflection and transmission coefficients at a plane interface between two anisotropic media constitute the elements of the elastic scattering matrix. For a 1-D anisotropic medium the eigenvector decomposition of the system matrix of the transformed elasto-dynamic equations is used to derive a general expression for the scattering matrix. Depending on the normalization of the eigenvectors, the expressions give scattering coefficients for amplitudes or for vertical energy flux.Computing the vertical slownesses and the corresponding polarizations, the eigenvector matrix and its inverse can be found. We give a simple formula for the inverse, regardless of the normalization of the eigenvectors. When the eigenvectors are normalized with respect to amplitudes of displacement (or velocity), the calculation of the scattering matrix for amplitudes is simplified.When the relative changes in all parameters are small, a weak-contrast approximation of the scattering matrix, based on the exactly determined polarization vectors in an average medium, is obtained. The same approximation is also derived directly from the transformed elasto-dynamic equations for a smooth vertically inhomogeneous medium, proving the consistency of the approximation.For monoclinic media, with the mirror symmetry plane parallel to the interface, the approximative scattering matrix is given in terms of analytic expressions for the non-normalized eigenvectors and vertical slownesses. For transversely isotropic media with a vertical axis of symmetry (VTI) and isotropic media, explicit solutions for the weak-contrast approximations of the scattering matrices have been obtained. The scattering matrix for amplitudes for isotropic media is well known. The scattering matrix for vertical energy flux may have applications in AVO analysis and inversion due to the reciprocity of the reflection coefficients for converted waves.Numerical examples for monoclinic and VTI media provide good agreement between the approximative and the exact reflection matrices. It is, however, expected that the approximations cannot be used when the symmetry properties of the two media are very different. This is because the approximation relies on a small relative contrast between the eigenvectors in the two media.Presented at the Workshop Meeting on Seismic Waves in Laterally Inhomogeneous Media, Castle of Trest, Czech Republic, May 22–27, 1995.  相似文献   

Estimation of azimuth and slowness of tele-seismic signals recorded by a local seismic network     

靳平  潘常周 《地震学报(英文版)》2002,15(6):646-655

Introduction The azimuth and slowness are two major features of seismic signals. The accurate estimation of them is quite important for both phase identification and event location. Generally, there are two types of seismic stations, i.e. 3-component stations (3C) and arrays. To estimate the two direc-tional parameters, the polarization analysis (Jurkevics, 1988) is commonly used for 3C stations and the frequency-wavenumber spectrum analysis ( f-k) (Capon, 1969; Kvaerna, Doornbos, 1986) is …  相似文献   

由地方台网记录确定远震信号的方位角和慢度          下载免费PDF全文

靳平  潘常洲 《地震学报》2002,24(6):617-626

介绍一种新的适合于地方遥测台网数据处理的方法，估算远震信号到达台站的方位角和慢度．该方法是根据信号在各台站上的到时与台站位置矢量在信号传播方向上的投影之间的相关性的原理．实际分析结果表明，应用该方法对地方台网的记录进行处理时可以准确地计算出信号的方位角和慢度，并能准确快捷地对地方台网记录的远震信号进行解释．   相似文献   

新技术在北极星天文方位角测量中的应用     

赵珞成  熊瑛 《测绘信息与工程》2003,28(3):37-39

使用GPS接收机的UTC作为北极星天文方位角测量的时间比对的标准时间，利用推估UTl与UTC的差值，将时间归算到UTl的方法，可满足各等级天文方位角测量的要求，现场计算零点恒星时和北极星坐标的精度满足北极星天文方位角测量的要求，实现了现场评估测量精度。  相似文献   

铁路隧道GPS网布设的精度分析     

姚连璧  沈云中  胡丛玮  刘大杰 《武汉大学学报(信息科学版)》1997,(2)

探讨了隧道ＧＰＳ网在设计阶段估算横向贯通误差的基本理论，对按该理论编制的软件进行了计算正确性的验证。结合铁路测量规则对不同长度的隧道ＧＰＳ网横向贯通误差进行了计算分析，提出了分设隧道ＧＰＳ网的一些基本原则和隧道ＧＰＳ网横向贯通误差的近似估算方法  相似文献   

利用地震属性研究准噶尔盆地西北缘拐19井区下侏罗统三工河组沉积环境   总被引：6，自引：0，他引：6       下载免费PDF全文

王世瑞  彭苏萍  凌云  王晓平  吴琳 《古地理学报》2005,7(2):169-184

在准噶尔盆地西北缘，寻找岩性圈闭油气藏已是至关重要的问题。但人们几乎还是用常规的手段来寻找岩性油气藏，没有实质性进展。本文是以利用宽方位角采集的地震数据为基础，对数据进行高保真资料处理和参考标准层的层拉平解释。利用前人的区域地质研究成果和钻井解释成果对侏罗系的沉积环境进行了精细的描述，确定了拐19井区在下侏罗统三工河组的出油层段附近的沉积环境由湖泊相－三角洲前缘相－河流相－湖泊相的演化过程。利用地震属性解释的结果也能较好地反映目标区的沉积环境变迁，并且与区域地质、测井解释结果相吻合，为寻找油气提供了很好的依据。由此得出利用地震属性可以进行沉积环境变迁分析，为油田寻找岩性圈闭及油气藏做出贡献。  相似文献