昆明机场红土地层地下结构抗震模拟研究     

周全通  周志国  许少清  龚仙贵 《地质灾害与环境保护》2020,(1):35-43

昆明机场残积红土既是区域内重要的土地资源,更是各类工程建设的建筑地基,由于机场及临近区域内小江地震活动断裂带和普渡河断裂带地震活动频繁,使研究区处于较不稳定状态。本文采用MIDAS GTS有限元数值分析软件,利用动三轴试验所得出的结果,分别对昆明长水国际机场玄武岩残积红土、砂页岩残积红土地层下典型的地下结构进行了抗震模拟研究。所获得的研究成果,对红土分布区城市及村镇房屋建筑地基和地下空间结构抗震安全稳定性评价具有一定的指导意义和实用价值。  相似文献   

中国东南陆缘的深部结构与动力学过程     

王椿镛  陈运泰  邵占英 《大地测量与地球动力学》1998,(2)

对我国东南陆缘地区的人工地震测深、大地电磁测深、重磁测量、地热测量、地学大断面编制以及天然地震的层析成像等大量深部构造研究结果作综合分析。地热异常、地壳内存在低速层和高导层、强烈地震频繁发生等现象说明,这一地区是现代构造运动的活动区。中国东南陆缘的现今应力场主压应力方向为ＮＷＷ－ＳＥＥ,认为是菲律宾板块对欧亚板块的挤压,以及冲绳海槽的扩张等联合作用的结果。因此,这一地区地壳运动的驱动力是太平洋板块和菲律宾板块向欧亚板块推挤产生的。  相似文献   

武汉台重力长期变化分析     

徐建桥  许厚泽  孙和平  罗少聪 《大地测量与地球动力学》1998,(3)

通过对武汉台超导重力仪９年多连续观测的重力长期变化资料分析,得到长周期重力潮汐参数、该频段气压回归因子Ｃ、极移重力效应因子Ｐ和长周期气压回归因子Ｃ１分别为：Ｃ：－０．３８３（±０．０１４）×１０－８ｍ·ｓ－２／１００Ｐａ;Ｍｍ：１．１１７３（±０．０７２０）,－１°．１７８７（±３°．６９４３）;Ｍｆ：１．１４３２（±０．０４８４）,５°．２２３５（±２°．４２５３）;Ｍｔｍ：１．２２７６（±０．２２４５）,－１７°．５６４８（±１０°．４７５８）;Ｃ１：－０．３１２（±０．０１５）×１０－８ｍ·ｓ－２／１００Ｐａ;Ｐ：１．９０４７（±０．０６９５）．重力长期变化在Ｃｈａｎｄｌｅｒ周期附近的振幅约为３．２６×１０－８ｍ·ｓ－２。  相似文献   

A VARIATIONAL METHOD FOR COMPUTING POTENTIAL COEFFICIENTS USING DIFFERENT TYPES OF GRAVIMETRIC DATA     

GUO Junyi  Associate Professor  Laboratory for Modern Geodynamics  WTUSM  Wuhan  China   《地球空间信息科学学报》1998,(1)

In this paper,a variational method is presented for solving theclassical gravimetric,satellite gravimetric and satellite altimetric mixed typeboudary value problem to obtain the potential coefficients.According to thisprinciple,classical gravimetric data（height measured by geometric levelling orheight triangulation）,satellite gravimetric data（height measured by satellitegeodesy technique）and satellite altimetric data can be used jointly to calculate thepotential coefficients.  相似文献   

内蕴大地边值问题     

黄金水  朱灼文 《武汉大学学报(信息科学版)》1998,(3)

提出内蕴大地边值问题,使得有可能利用重力场边界观测研究地球重力场的内蕴结构。文中构造了椭球问题的迭代逼近求解程式,并给出了具体解式。  相似文献   

华北克拉通基性火山岩高场强元素对Ar-Pt界限及新生代地幔源区特征的示踪   总被引：5，自引：0，他引：5       下载免费PDF全文

刘勇胜  高山  骆庭川 《地球科学》1998,23(5):91

华北克拉通不同时代基性火山岩存在向富集方向演化的趋势,并出现明显的Ａｒ－Ｐｔ界限和新生代异常．元古宙基性火山岩比太古宙富集大部分高场强元素（ＨＦＳＥ）和轻稀土元素（ＬＲＥＥ）,ＲＥＥ分异程度显著增加,而且相容性接近的不相容元素（如Ｎｂ,Ｔａ）的相对不相容性发生了改变．新生代玄武岩ＨＦＳＥ及Ｎｉ高度富集,ＲＥＥ强烈分异,δ（Ｅｕ）值最高．Ａｒ－Ｐｔ界限可能与地幔熔融时物理条件（如氧逸度）的改变和地幔富集作用有关．新生代玄武岩独特的地球化学特征可能主要反映了地幔源区的特殊性———“似ＯＩＢ型”富集地幔,其形成既可能有携带远洋沉积物的俯冲古老玄武岩洋壳部分熔融残余的贡献,也可能有直接循环（如通过拆沉作用）的陆壳物质的贡献,同时还可能涉及了地幔柱活动的影响．  相似文献   

Secular variation of the poloidal magnetic field at the core–mantle boundary     

Archana Bhattacharyya 《Geophysical Journal International》1998,132(1):181-190

A region of enhanced conductivity at the base of the mantle is modelled by an infinitesimally thin sheet of uniform effective conductance adjacent to the core–mantle boundary. Currents induced in this sheet by the temporally varying magnetic field produced by the geodynamo give rise to a discontinuity in the horizontal components of the poloidal magnetic field on crossing the sheet, while the radial component is continuous across the sheet. Treating the rest of the mantle as an insulator, the horizontal components of the poloidal magnetic field and their secular variation at the top of the core are determined from geomagnetic field, secular variation and secular acceleration models. It is seen that for an assumed effective conductance of the sheet of 10⁸  S, which may be not unrealistic, the changes produced in the horizontal components of the poloidal field at the top of the core are usually ≤10 per cent, but corrections to the secular variation in these components at the top of the core are typically 40 per cent, which is greater than the differences that exist between different secular variation models for the same epoch. Given the assumption that all the conductivity of the mantle is concentrated into a thin shell, the present method is not restricted to a weakly conducting mantle. Results obtained are compared with perturbation solutions.  相似文献   

Seismic wavefield calculation for laterally heterogeneous whole earth models using the pseudospectral method   总被引：4，自引：0，他引：4  

T. Furumura  B. L. N. Kennett  & M. Furumura 《Geophysical Journal International》1998,135(3):845-860

  相似文献   

Electromagnetic 2.5-dimensional forward modelling with a boundary integral formulation     

E. Ngakosso  A. Straub  M. Saillard  P. Vincent 《Geophysical Journal International》1998,135(3):1028-1044

An effective and accurate technique for the numerical solution of 2-D electromagnetic scattering problems with 3-D sources is presented. This solution introduces a set of the usual boundary integral equations and uses a scalar Green's function. In this scalar version, the unknowns of the problem are the boundary values of the longitudinal fields and their normal derivatives in the Fourier domain. A generalization of the usual boundary integral formulation enables us to handle a large class of models composed of piecewise homogeneous domains, including contiguous domains, multiply-connected domains and unbounded domains. This formulation involves the solution of a system of linear equations, and results in a significant saving in computation time in comparison with other rigorous methods.
  The requirements for the numerical implementation of this solution are described in detail. Numerical tests were carried out using the important example of electromagnetic tomography. The specific symmetry properties of the response function in this case are illustrated. Numerical accuracy is verified over a large frequency range, up to 1  MHz.  相似文献   

On the solar cycle dependence of winds and planetary waves as seen from mid-latitude D1 LF mesopause region wind measurements     

C. Jacobi 《Annales Geophysicae》1998,16(12):1534-1543

At the Collm Observatory of the University of Leipzig LF D1 low-frequency total reflection nighttime wind measurements have been carried out continuously for more than two decades. Using a multiple regression analysis to derive prevailing winds, tides and the quasi-2-day wave from the half-hourly mean values of the horizontal wind components, monthly mean values of mesopause wind parameters are obtained that can be analysed with respect to long-term trends and influences of solar variability. The response of the prevailing wind to the 11-year solar cycle differs throughout the year. While in winter no significant correlation between the zonal prevailing wind and solar activity is found, in spring and summer a negative correlation between the TWC can be seen from the measurements. This is connected with stronger vertical gradients of the zonal prevailing wind during solar maximum than during solar minimum. Since the amplitude of the quasi-2-day wave is dependent on the zonal mean wind vertical gradient, this is connected with a positive correlation between solar activity and quasi-two-day wave activity.Paper Presented at the Second IAGA/ICMA (IAMAS) Workshop on Solar Activity Forcing of the Middle Atmosphere, Prague, August 1997  相似文献