Inference of core-mantle boundary topography from ISC PcP and PKP traveltimes

We invert ISC PcP and PKP absolute and differential traveltimes in an attempt to infer the long-wavelength topography of the core-mantle boundary (CMB). The data selection and processing methods are described and evaluated. These travel-time data are very noisy and the geographic distribution of the data is highly non-uniform, inhibiting reliable inference of CMB topography. Spatial averaging enhances the coherent component of the residual variance (related to heterogeneity), however, the random component of the variance is much larger than the coherent component. We show that for PcP data the coherent signal due to mantle heterogeneity overshadows that arising from the CMB, and that the effects of mantle heterogeneity are mapped into our inferred CMB solutions. The PcP data are not correlated across the spatial averaging bins and seem to have a strong bias due to small-scale structure and/or noise. The non-uniform geographic sampling of the data plays a role in the mapping of mantle heterogeneity onto the CMB. Spatial patterns of CMB models inferred from different phases do not agree. Amplitudes of seismically inferred CMB undulations vary greatly. The sensitivity of inferred CMB models to the processing, spatial averaging procedure, and inversion techniques are investigated. Topographic amplitudes increase strongly with increasing input residual variance. The power spectrum of inferred topography indicates that there are unmodelled heterogeneities that must be described with spherical harmonics of degree 6 and higher. Based on this work, we conclude that reliable inference of long-wavelength CMB topography is not likely with the current ISC data set or with a spherical harmonic expansion truncated to degree and order 6.     

类透镜介质中的传导模及与激光束的耦合

从求解柱坐标内亥姆霍兹方程出发，导出了类透镜介质传导模的特征参量、场分布状态及传播常数，求出了入射激光束和导模之间的耦合系数，并讨论了它们的物理意义．     

气压场巨涨落与非线性地震系统状态的突变和临震预报研究（上）

本研究以非线性孕震系统在爆发前夕的外敏性为物理基础，对大气扰动下的岩体失稳突变问题进行了初步的探讨，给出了气─－地耦合的一般表示，并连续分析了云南近３５年来大气压力场演化与场内近百次５级以上地震（内含１９次６级，４次７级）的基本关系，系统地证明了绝大部分强震都是在其上覆大气涨落加剧及与邻区气压梯度增大时突然爆发的，这种自然共性的揭示，既是对理论的认证，也丰富了短临地震预报的科学依据。     

磁层系统的能量输入、输出与日地耦合

用１９７８年和１９８２年３６个磁暴期间的太阳风、行星际磁场（ＩＭＦ）和地磁资料，分析和检验已有的两类太阳风－磁层能量耦合函数．结果表明：Ａｋａｓｏｆｕ提出的耦合函数ε能大致地预报亚暴和磁暴的发生。ε开始起重要作用时即出现亚暴；电离层能耗达到饱和值是发生磁暴的标志。ε与磁层体系能耗之间有接近于对数量的线性关系．用１９７８－１９８６年的资料，分析环电流和极光区电离层能耗在１２１个太阳自转周内的分布表明，日面上可能存在相对持久的活动区域     

Application of stress-pore pressure coupling theory for porous media to the Xinfengjiang reservoir earthquakes

Theory of the coupling of stress-pore pressure in the saturated, elastic porous media is used in the study of the formation mechanism of the Xinfengjiang reservoir-induced earthquakes. Based on the results, it is believed that compared with the mechanism of additional stress in the vicinity of the reservoir, the mechanism of the coupling of additional stress and pore pressure may be more well-founded for the occurrence of reservoir-induced earthquakes.     

TWO DIMENSIONAL FINITE ELEMENT-BOUNDARY ELEMENT COUPLING MODEL OF MAGNETOTELLURIC SOUNDING

This paper describes how to apply the boundary element method to solve 2-D magneto-telluric sounding problem and then couple the BEM with finite element method to deal with inhomogeneous geological structure and its relation to regional stress regime. The BEM is able to calculate precisely the derivative of field variables. Such a new approach can more flexibly than others set up the upper boundary condition of the air region. Two practical examples are given. One is the study of topographical effect on the MT fields using boundary element method. There is an inverse relationship between the change of apparent resistivity and the topographical variation. The other is a coupled model of a basin in Nei Monngol Autonomous Region. A lower resistivity zone must exist in the crust and should be thicker below the central portion of the basin. This seems to agree with the regional stress regime changed from extension in Mesozoic to compression in Cenozoic     

地下水开采—地面沉降模型研究

本文建立三维流支－－一维非线性固结地面沉降模型,在混合井流,降雨滞后补给,初始水头形成,人为边界刻画,水流－固结耦合及软土层固结滞后于地下水开采层水头变化等方面有所改进,所建模型用于苏州市,模拟出若干地面沉降重要特征,地面沉降中心偏离地下水漏斗中心,地面沉降动态滞后于地下水的水头动态,软土层渗透系数随固结过程的变化及头在软土层中的传递特征。