二维弹性波动方程F—K正演与偏移     

陈志文  贺振华 《物探化探计算技术》1996,18(2):171-176

根据Ｈｏｏｋｅ定律，消除应力矢量后得到弹性波动方程位移矢量和波势矢量的非耦合形式递推解，在这个解答中各种类型的波相互分离，但在界面上满足能量守恒定律。正演可变步长延拓；偏移是将震源脉冲和地面记录波场同时下延，然后在每个深度作时间零延迟互相关来完成。由于延拓和成像在频率波数域（Ｆ—Ｋ）中进行，因而算法快速、偏移和正演可方便地扩展到三维空间，能处理各向同性任意非均匀介质中的弹性波。  相似文献   

高氟水灌溉区水－土－植物系统氟迁移转化环境效应分析──以河北沧县为例     

杨军耀 《地学前缘》1996,3(2):241-244

文章以河北沧县高氟水灌溉区土壤氟的积累与分布特征、氟等温吸附试验、吸附动力学试验、土柱模拟试验以及农作物含氟量为依据，对高氟水灌溉区水－土壤－植物系统氟迁移转化环境效应进行讨论分析，并提出了防止氟环境恶化的对策。  相似文献   

Imaging of convergent zones by seismic acquisition and processing     

Manik  Talwani Walter  Kessinger 《Island Arc》1997,6(3):327-335

Abstract The complex crustal geology of convergent zones requires carefully planned seismic experiments for accurate imaging. Situations that require 2-D or 3-D experiments, pre-stack or post-stack processing, and time or depth migration, are discussed. Some of the advanced techniques available for seismic processing are described. Some results of 3-D post-stack depth migration of a 3-D data set on the Barbados margin that were obtained by the University of Texas Institute of Geophysics and reprocessed at the Houston Advanced Research Center illustrate the advantage of three-dimensionality, and the value of advanced processing techniques.  相似文献   

Evidence of fluid inclusion for thermal fluid-bearing hydrocarbon movements in Qiongdongnan Basin, South China Sea   总被引：5，自引：0，他引：5  

Honghan Chen  Qiming Zhang  Jixi Shi 《中国科学D辑(英文版)》1997,40(6):648-655

Diagenetic research and inclusion observance indicate that there are seven types of inlcusion in the reservoirs in the Qiongdongnan Basin. Based on the fluorescence color, ratio of gas/liquid, formation temperature, salinity and organic component of fluid inclusions, three events of thermal fluid movement were found, and only the second and third events are relative to hydrocarbon migration and accumulation with the temperatures of 140–150°C and 170–190°C., respectively.The mechanism of gas migration in aqueous phase suggests that the discharging site of thermal fluid is the favourable location for natural gas accumulation. Project supported by the Natlonal Natural Science Foundation of China.  相似文献   

Migration Patterns During a Period of Political and Economic Shocks in the Former Soviet Union: A Case Study of Yaroslavl' Oblast*     

Beth Mitchneck  David Plane 《The Professional geographer》1995,47(1):17-30

This paper examines migration in Russia during the period that preceded the breakup of the former Soviet Union (FSU) and during the current transition period. An unusually rich dataset is used to conceptualize the impact that the political and economic collapse of a world superpower has on a migration system. A regional case study of migration in Yaroslavl' Oblast from 1989 through 1992 is used to examine the relevance of expected outcomes given standard theories of migration, empirical regularities found in capitalist economies, and past trends in the FSU. The data clearly show a migration system undergoing political and economic shocks. A significant decline of the volume of flows and a relative increase in the importance of interrepublic movement indicate disruptions. Increased relative mobility for those in the later years of the working-age population and increased importance of urban-to-rural migration flows are also important changes evident in this migration system undergoing shock.  相似文献   

有限元素法全倾角波动方程偏移   总被引：2，自引：0，他引：2       下载免费PDF全文

王尚旭  牟永光 《地球物理学报》1989,32(3):308-318

本文试图从两个方面提高波动方程偏移的效果:1.使用全方向波动方程进行偏移,使之适用于任意倾角界面的反射;2.使用有限元素法提高微分方程数值解法的精度。  相似文献   

Elemental composition of particulate material sampled from the Arctic haze aerosol     

Patrick J. Sheridan  William H. Zoller 《Journal of Atmospheric Chemistry》1989,9(1-3):363-381

Thirty-six aerosol filter samples collected in tropospheric Arctic haze layers, in the stratosphere, and in the marine boundary layer during the 1983 Arctic Gas and Aerosol Sampling Program were analyzed for trace elements using instrumental neutron activation analysis. Average crustal dust concentrations were 540 ng/m³ and 330 ng/m³ for samples collected in Arctic haze over the North American and Norwegian Arctic, respectively. An average marine salt concentration of 120 ng/m³ was obtained for haze samples collected above the marine boundary layer on both sides of the Arctic.Meteorological and wind trajectory information were used to identify specific haze transport pathways, which brought relatively unmixed aerosol from the central Soviet Union into the AGASP sampling areas. Results from individual filters collected within these transport zones are discussed, with emphasis on certain trace metal ratos which have been proposed by other researchers as discriminators of aerosols from different source regions. Our aircraft-collected data are compared with previously-collected ground-based measurements, and show reasonably good agreement for most tracer elements and ratios. Specifically, we have determined the As/Sb ratio tracer, named by other researchers as the most effective elemental discriminator of aerosol from the central Soviet Union, to be approximately 5–6. This relatively high tracer value is consistent with previous ground-based findings. A significantly lower V/Sb ratio was observed throughout this study, possibly indicating a change in the source signature.  相似文献   

某区放射性水文地球化学特征及其地质意义     

翦勋平 《铀矿地质》1985,(4)

文章通过对某区放射性水文地球化学特征的研究,探讨了矿化水的成因和基本特征,铀在溶液中的存在形式,含铀水迁移强度;铀和氡在水中的迁移距离;水化学组分与矿化的关系。总结了工作区的放射性水化学找矿标志和评价水晕的综合判别准则。在研究的基础上,预测了新的成矿远景地段,提出了现有矿床可能属于后生气热水改造复成因矿床的假说以及根据这些假说似算这类矿床铀总量的方法。  相似文献   

The turnaround in Australia: some first observations from the 1991 census     

Hugo G 《The Australian geographer》1994,25(1):1-17

"The aim of this paper is to utilise recently released census results to examine patterns of population change in non-metropolitan Australia during the 1986-91 period, focusing particularly upon the net migration component of that change. The paper presents an overview of recent trends in population change in non-metropolitan areas and then moves to an analysis of net migration patterns in non-metropolitan local government areas during the late 1980s using a Life Table Survival Ratio technique to estimate net migration. It appears that the trends observed in the early 1980s have continued into the late 1980s and early 1990s, and that overall the 'turnaround' is slowing down and becoming more diversified, more complex, and much less predictable in the 1990s."  相似文献   

西部复杂地区地震资料处理方法     

李锋  曾庆才  吕金博  张建成 《物探与化探》2004,28(2):159-163

塔中、焉耆盆地和巴彦浩特等西部地区的表层地震地质条件差,地下地质构造复杂。针对该类地区地震资料静校正问题突出、反射信号能量弱、各种干扰波极其发育以及偏移成像差的特点,在大量的分析、试验基础上,确定了一套以解决静校正、提高信噪比和改善偏移成像精度为主要目标的地震资料处理方法。经实际验证,此方法有效地提高了该类地区地震资料的信噪比和偏移成像的精度,取得了良好的效果。  相似文献