经济全球化与国家能源安全

经济全球化进程的加快对国家经济安全提出了挑战。其中能源安全问题引起我国的关注。伴随着我国经济的快速增长和人民生活水平的提高，我国对能源的依赖程度不断提高。加强能源安全已成为21世纪中国经济社会可持续发展的重要问题之一。     

天然气水合物研究现状与展望

自20世纪90年代以来,世界各国对潜力巨大的新型能源———天然气水合物的研究做了大量的投入,已经取得了重大进展。本文在阐述国外天然气水合物的研究现状的同时,重点介绍了我国在天然气水合物勘探开发和实验模拟方面取得的一些进展,并展望其在能源、环境和其它研究领域的发展前景。     

烃类垂向微渗漏及其地表异常显示

烃类以微泡、水动力、扩散和渗透方式向地表迁移过程中,其效能、方式与油气藏的盖层、断裂与裂隙系统、储层的流体性质、地层压力等地质因素密切相关.通过对塔里木盆地雅克拉凝析气田上的地表、井中化探资料与地质资料的综合分析,认为该气田的井中垂向地球化学特征、控制烃类垂向微渗漏地质因素、地表化探异常显示之间呈现出很好的内在联系.     

底质不连续面类型、成因及遗迹学特征

底质不连续面是沉积作用中断时所形成的一种地层界面。根据底质的粘结程度可将底质不连续面划分为两大类：固底不连续面和硬底不连续面。固底不连续面中的简单停积面依靠沉积序列的变化来识别，界面上、下的生物地层带是连续的；而复成停积面上、下的生物地层带不连续。在硬底不连续面中，硬底的上、下地层属于同一个沉积体系，而继承性岩底的上、下地层则属于不同的沉积体系，其间发生过重大的沉积间断。根据底质控制的Glossifungites遗迹相和Trypanites遗迹相可以有效地识别各类不连续面并解释其成因。三种类型的不连续面具有层序地层学意义：①侵蚀性不连续面，包括低水位侵蚀面（LSE）和海进侵蚀面（TSE）；②无沉积间断面；③沉积性不连续面（凝缩段）。     

Seismic evidence for deep low-velocity anomalies in the transition zone beneath West Antarctica

We present a three-dimensional (3D) SV-wave velocity model of the upper mantle beneath the Antarctic plate constrained by fundamental and higher mode Rayleigh waves recorded at regional distances. The good agreement between our results and previous surface wave studies in the uppermost 200 km of the mantle confirms that despite strong differences in data processing, modern surface wave tomographic techniques allow to produce consistent velocity models, even at regional scale. At greater depths the higher mode information present in our data set allows us to improve the resolution compared to previous regional surface wave studies in Antarctica that were all restricted to the analysis of the fundamental mode. This paper is therefore mostly devoted to the discussion of the deeper part of the model. Our seismic model displays broad domains of anomalously low seismic velocities in the asthenosphere. Moreover, we show that some of these broad, low-velocity regions can be more deeply rooted. The most remarkable new features of our model are vertical low-velocity structures extending from the asthenosphere down to the transition zone beneath the volcanic region of Marie Byrd Land, West Antarctica and a portion of the Pacific-Antarctic Ridge close to the Balleny Islands hotspot. A deep low-velocity anomaly may also exist beneath the Ross Sea hotspot. These vertical structures cannot be explained by vertical smearing of shallow seismic anomalies and synthetic tests show that they are compatible with a structure narrower than 200 km which would have been horizontally smoothed by the tomographic inversion. These deep low-velocity anomalies may favor the existence of several distinct mantle plumes, instead of a large single one, as the origin of volcanism in and around West Antarctica. These hypothetical deep plumes could feed large regions of low seismic velocities in the asthenosphere.     

冻土路基表面的融化指数与冻结指数

在冻土层之上筑路，由于会改变地-气界面的热物理特性，进而影响冻土层的热力→动力稳定性，故而修筑一定高度的路基成为保护冻土层所采取的一种常规措施．在修筑路基之后，与路基边坡的朝向有关的热效应是冻土路基工程保护措施必须考虑的问题．在数理分析与数值模拟分析的基础上，给出了可根据气温的年最大和最小月平均值计算路基表面的融化指数与冻结指数以及有关热状况参数的方法，并以青藏铁路北麓河段2002年为例进行了计算分析．实例分析表明，即便是没有修筑道路，北麓河地区的冻土也已经处于临界状态；路基相对的两个坡面，由于朝向不同会造成温度分布的强非均匀性，其中南和偏南方向与北和偏北方向的路基坡面热状况差异最大，有必要对路基相对的两个坡面采用不同的防护措施，一方面改善就地取土修筑路基对其下伏冻土层的直接不良影响，同时也尽可能减小路基表面温度分布的非均匀性，以避免纵向裂缝的发生。     

A hybrid indirect boundary element—discrete wave number method applied to simulate the seismic response of stratified alluvial valleys

A hybrid indirect boundary element – discrete wavenumber method is presented and applied to model the ground motion on stratified alluvial valleys under incident plane SH waves from an elastic half-space. The method is based on the single-layer integral representation for diffracted waves. Refracted waves in the horizontally stratified region can be expressed as a linear superposition of solutions for a set of discrete wavenumbers. These solutions are obtained in terms of the Thomson–Haskell propagators formalism. Boundary conditions of continuity of displacements and tractions along the common boundary between the half-space and the stratified region lead to a system of equations for the sources strengths and the coefficients of the plane wave expansion. Although the regions share the boundary, the discretization schemes are different for both sides: for the exterior region, it is based on the numerical and analytical integration of exact Green's functions for displacements and tractions whereas for the layered part, a collocation approach is used. In order to validate this approach results are compared for well-known cases studied in the literature. A homogeneous trapezoidal valley and a parabolic stratified valley were studied and excellent agreement with previous computations was found. An example is given for a stratified inclusion model of an alluvial deposit with an irregular interface with the half-space. Results are displayed in both frequency and time domains. These results show the significant influence of lateral heterogeneity and the emergence of locally generated surface waves in the seismic response of alluvial valleys.     

A quantitative study of the energy release in the aftershocks of the Bhuj earthquake, 2001, India, using Lg phase

The devastating earthquake on 26 January 2001 at Bhuj, India, resulted in large-scale death and destruction of properties of several million US dollars. The moment magnitude of the earthquake was 7.7 and its maximum focal intensity exceeded X in MM scale. The rate of aftershocks of this earthquake, recorded at Gauribidanur seismic array station (GBA), shows a monotonic decay with time superposed with oscillations. For the Indian continent the Lg phase is a prominent arrival at regional distances. The estimate of Lg amplitude is obtained by optimally fitting the Lg wave train to a exponential decay curve. The logarithm of these amplitudes and logarithm of root mean square (rms) value of actual amplitudes of the Lg are calibrated with USGS m_b to create a local m_bLg magnitude scale. The energy released from these aftershocks is calculated from the rms value of Lg phase. The plot of cumulative energy release with time follows the power law of the form t^p, superposed with oscillations. The exponent of the power law, p, is estimated both by a time-window scanning method and by an interpolation method. The value of p is 0.434 for time-window scanning method and 0.432 for the interpolation method. The predominant periods found in the oscillatory part of the cumulative energy, obtained by differencing the observed from the power law fit, are 10.6, 7.9, 5.4, 4.6 and 3.5 h for time-window scanning method. The corresponding periods for interpolation method are 13.4, 11.5, 7.4, 4.2, 3.5, 2.6 and 2.4 h.     

Optimal distribution of linear control intensity over the frequency range

In this paper, a control strategy for structural systems is proposed and developed in the frequency domain. The algorithm is substantially based on a linear derivative feedback and a convolution of the control parameter, whose distribution in the frequency field is chosen in such a manner as to comply with the requirements of an ad hoc formulated constrained optimum problem, with the response data monitored until the instant of control action application. Some numerical testing is carried out by referring to given recorded accelerograms, showing a good performance of the proposed approach. Copyright © 2002 John Wiley & Sons, Ltd.     

停止开采深层地下水 修复与改善生态环境

沧州市水资源短缺，深层地下水严重超采，已形成大面积区域地下水位降落漏斗，地面沉降已达2m，生态环境严重恶化．为保障经济社会的可持续发展，要积极引调地表水，开发利用地下咸水，加强雨洪控制利用，逐步替代最后终止深层地下水的开采。从根本上修复和改善生态环境。