震源耦合的等效物理模型     

薄景山  廖振鹏 《地震工程与工程振动》1996,16(3):11-21

本文提出了考虑各潜在震源相互耦合的等效物理模型，系统地建立了通过拟合各潜在震源地震序列来确定不同时间段内活断层形速率的方法，给出了预报各潜在震源未来一定年限内发生震级在不同震级段的概率模型。  相似文献   

计算机辅助绘制流域等流时线   总被引：4，自引：0，他引：4  

王腊春  陈晓玲 《地理科学》1996,16(2):184-190

采用地理信息系统方法，对流域的地形地貌特征进行分析，模拟水质点在流域上的运动轨迹，并根据水质点汇流时间与汇流路径，坡度，坡长的关系，建立了流域汇流等流时线模型，经实例验证，效果较好。  相似文献   

A　Comparative　Study　of　the　Atmospheric　Layers　below　First　Lifting　Condensation　Level　for　Instantaneous　Pre-Monsoon　Thunderstorm　Ocurence　at　Agartala(23°30′N,91°15′E)　and　Ranchi(23°14′N,85°14′E)　of　India     

Sarbari Ghosh  Utpal Kumar De Atmospheric Science Research  Department of Physics  Jadavpur University  Calcutta  India Received April    revised July   《大气科学进展》1997,(1)

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武昌电离层E-F谷区白天变化形态   总被引：2，自引：0，他引：2       下载免费PDF全文

苏元智  黄信榆 《地球物理学报》1987,30(6):555-559

本文利用文献[4]的分析程序对武昌地区三年共300多张频高图作了剖面换算和统计分析,得出白天E-F谷区电离的基本形态并发现一些新的变化特征;对分析结果的可能原因提出了讨论。  相似文献   

Decoupled seismic analysis of an earth dam   总被引：2，自引：0，他引：2  

Ernesto Cascone  Sebastiano Rampello 《Soil Dynamics and Earthquake Engineering》2003,23(5):349-365

The seismic stability of an earth dam is evaluated via the decoupled displacement analysis using the accelerograms obtained by ground response analysis to compute the earthquake-induced displacements. The response analysis of the dam is carried out under both 1D and 2D conditions, incorporating the non-linear soil behaviour through the equivalent linear method. Ten artificial and five real accelerograms were used as input motions and four different depths were assumed for the bedrock.1D and 2D response analyses were in a fair agreement with the exception of the top third of the dam where only a 2D modelling of the problem could ensure that the acceleration field is properly described. The acceleration amplification ratio obtained in the 2D analyses was equal to about 2 in all the cases considered, consistently with data from real case histories.The maximum permanent displacements computed by the sliding block analysis were small, being less than 10% of the service freeboard; a satisfactory performance of the dam can then be envisaged for any of the seismic scenarios considered in the analyses.  相似文献   

重磁遗传算法三维反演中高速计算及有效存储方法技术   总被引：13，自引：15，他引：13       下载免费PDF全文

姚长利  郝天珧  管志宁  张聿文 《地球物理学报》2003,46(2):252-258

将地下场源区域规则划分成很多小长方体单元，并且通过反演确定这些单元的物性变 化，勾画出场源的分布图像，这种方式逐步成为重磁反演，特别是三维反演的重要方向；遗 传算法等非线性技术进行该类反演将逐步成为发展趋势. 本文指出，在应用遗传算法进行该 类反演过程中，隐含着数据量较大时超常规的计算量，它已成为制约该类反演充分发挥作用 的瓶颈问题；同时，本文提出了针对性的分离并存储几何格架的计算策略、以及独特的几何 格架等效压缩存储技术，可以从根本上提高非线性反演计算速度，为该类反演的有效应用奠 定了坚实的基础.  相似文献   

Efficiency of base isolation systems in structural seismic protection and energetic assessment     

Giuseppe Carlo Marano  Rita Greco 《地震工程与结构动力学》2003,32(10):1505-1531

This paper concerns the seismic response of structures isolated at the base by means of High Damping Rubber Bearings (HDRB). The analysis is performed by using a stochastic approach, and a Gaussian zero mean filtered non‐stationary stochastic process is used in order to model the seismic acceleration acting at the base of the structure. More precisely, the generalized Kanai–Tajimi model is adopted to describe the non‐stationary amplitude and frequency characteristics of the seismic motion. The hysteretic differential Bouc–Wen model (BWM) is adopted in order to take into account the non‐linear constitutive behaviour both of the base isolation device and of the structure. Moreover, the stochastic linearization method in the time domain is adopted to estimate the statistical moments of the non‐linear system response in the state space. The non‐linear differential equation of the response covariance matrix is then solved by using an iterative procedure which updates the coefficients of the equivalent linear system at each step and searches for the solution of the response covariance matrix equation. After the system response variance is estimated, a sensitivity analysis is carried out. The final aim of the research is to assess the real capacity of base isolation devices in order to protect the structures from seismic actions, by avoiding a non‐linear response, with associated large plastic displacements and, therefore, by limiting related damage phenomena in structural and non‐structural elements. In order to attain this objective the stochastic response of a non‐linear n‐dof shear‐type base‐isolated building is analysed; the constitutive law both of the structure and of the base devices is described, as previously reported, by adopting the BWM and by using appropriate parameters for this model, able to suitably characterize an ordinary building and the base isolators considered in the study. The protection level offered to the structure by the base isolators is then assessed by evaluating the reduction both of the displacement response and the hysteretic dissipated energy. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

位场DFT算法研究   总被引：5，自引：0，他引：5       下载免费PDF全文

柴玉璞 《地球物理学报》1988,31(2):211-224

本文推广了经典的抽样定理,并据此导出了函数有限离散傅里叶变换误差方程（简称DFT误差方程,下同）。该方程把有限离散傅里叶变换中固有的离散效应和有限效应表示为确切的数学形式。离散效应被表示为一个含整参变量（参变量取0,1,…,N-1）的复无穷级数;有限效应被表示为一个含整参变量（参变量取0,1,…,N-1）的复无穷级数的DFT。 基于DFT误差方程和位函数特点,作者提出了两种位场数值傅里叶变换新算法--移样法和等效源续尾叠样法。移样法可近百倍地提高位场数值傅里叶反变换的精度,等效源续尾叠样法可数十倍地提高正变换精度。两种算法都不需要增加资料长度和取样密度,因而基本不需要增加计算机时间和内存。文中给出了算例。  相似文献   

等效偏移距方法及应用   总被引：1，自引：1，他引：1       下载免费PDF全文

王伟  尹军杰  刘学伟  赵俊猛  王赟  黄英 《地球物理学报》2007,50(6):1823-1830

当勘探目标地质构造复杂、地层倾角较陡或岩性横向突变时，在地表接收到的反射信号较弱、信噪比较低，甚至接收不到反射波，常规偏移成像方法对这类数据很难精确成像，因此可以考虑基于散射理论的等效偏移距方法来成像.该方法分两步进行：第一步是抽取共散射点道集；第二步是对共散射点道集进行克希霍夫积分偏移.文中数值模拟及实际资料的实例表明，该方法在复杂地质目标及低信噪比地震资料的成像处理中具有一定的实用价值.  相似文献   

Numerical simulation of groundwater flowing to horizontal seepage wells under a river   总被引：6，自引：0，他引：6  

Wei Wang  Ge Zhang 《Hydrogeology Journal》2007,15(6):1211-1220

A horizontal seepage well, consisting of an interconnected vertical well, galleries, chambers and small-diameter radiating bores, is used to acquire relatively clean water that has been filtered through natural alluvial deposits in a riverbed. It has wide application, especially in arid and semi-arid areas. The lack of calculation formulae or models for horizontal seepage wells, up until now, has resulted in several false applications. Based on the analysis of groundwater flow characteristics, it has been concluded that several flow regimes coexist and hydraulic head loss exists in the horizontal seepage well. To avoid the difficulty of confirming the flux or head distribution in such a complex system, the model boundary of the whole horizontal seepage well has been moved to that of just the vertical well, and the well-aquifer system was treated as a heterogeneous medium, where the horizontal seepage well itself is a highly permeability medium. A mathematical model has been developed, based on the coupled seepage-pipe flow, by the introduction of equivalent hydraulic conductivity according to different flow regimes. Then a three-dimensional finite difference numerical model, based on the mathematical model, was developed and applied to a horizontal seepage well in China. The numerical model verified the groundwater flow characteristics of the horizontal seepage well. An erratum to this article can be found at  相似文献