3–D Tomographic Images and Deep Ore-Control in Northern Margin of the North China Plate

Abstract: 3–D velocity images of the crust beneath the northern margin of the North China Plate have been constructed using P-wave travel time residuals of the latest earthquakes, with the data supplied by Chinese seismic networks.
The seismic image results indicate that there is a lateral heterogeneity in the crust beneath the northern part of the North China block. The velocity images of the upper crust show features closely related to the tectonic features on the surface. It can be seen from these velocity images of the vertical sections, and from the horizontal slice images at depths of 11 and 16 km that there exist East-West and North-East structures. The images indicate that the juncture zone of basin–and–range terrain is between the blue-colored high–velocity block corresponding to the Yanshan mountain range that developed during the Yanshan period in northwest Beijing and the green low-velocity area corresponding to the North China basin in southeast Beijing (Fig. 5). The juncture zone between high-velocity and low–velocity, and EW and NE fault zones have significant ore-control effects. From the chart of epicenters in the northern region of North China, we find that the epicenters of earthquakes are almost entirely distributed within the NE strip. Almost all major earthquakes took place in the transition strip between the high and low-velocity zones in the crust. The distribution of epicenters also reflects the strikes of known NE–faults. From the image sections along the latitude, we find that in the area between 114.0 E –118.0 E , there is a blue high-velocity block standing upright from the Moho to the upper crust (Fig. 6), from which can be deduced that some materials such as magma moved upward from the upper mantle during the history of its geological development.     

Synchrotron X-ray powder diffraction study of natural P2 /n-omphacites at high-pressure conditions

 Synchrotron X-ray powder diffraction experiments at high pressure conditions (0.0001–13 GPa) were performed at ESRF (Grenoble-F), on the beamline ID9, to investigate the bulk elastic properties of natural P2/n-omphacites, with quasi-ideal composition. The monoclinic cell parameters a, b, c and β were determined as a function of pressure, and their compressibility coefficients are 0.00277(7), 0.00313(8), 0.00292(5) and 0.00116(4) GPa⁻¹, respectively. The third-order Birch-Murnaghan equation of state was used to interpolate the experimental P−V data, obtaining K ₀=116.6(±2.5) GPa and K′₀=6.03(±0.60). K ₀ was also determined by means of the axial and angular compressibilities [122.5(±1.7) GPa], and of the finite Lagrangian strain theory [121.5(±1.0) GPa]. The discrepancies on K ₀ are discussed in the light of a comparison between techniques to determine the bulk modulus of crystalline materials from static compression diffraction data. Received: 22 February 2000 / Accepted: 10 July 2000     

GPS工程控制网的若干特殊问题

根据ＧＰＳ定位技术的优点，讨论了建立ＧＰＳ工程控制网在踏勘、设计、观测及数据处理方面的若干特殊问题，并提出高精度工程控制网ＧＰＳ数据处理方案。     

浅地层剖面仪在水域工程勘察中的应用

扼要介绍了水上浅地层剖面仪的方法技术，列举了该法在浅海，内河和湖泊减种典型环境及相应的地质条件下勘测所得到的剖面记录及地质解释结果，指出了运用该方法所能解决的工程地质问题。     

高层建筑地震反应最优多重TLD控制

本文以坑层建筑地震反应进行了最优多重ＴＬＤ（ＭＴＬＤ）ｓ控制研究。文中阐述了ＴＬＤ系统的工作原理笔ＭＴＬＤｓ系统的参数；建立了多层结构－ＴＭＬＤｓ系统耦联体系的运动方程；分析了ＭＴＬＤｓ系统的参数对在谐波作用下多层结构动力反应的影响以及各参数之间的关系。     

地震空间分维Dq及b值的临震变化特征及其非线性机制分析

对云南省几个不同地区的强震孕震阶段及临震时的地震空间分维Ｄｑ（ｑ＝０，１，２，）及ｂ值进行了计算和研究，发现虽然在孕震阶段各地区的Ｄｑ及ｂ值均有着共同的下降主趋势，但临震时不同区域的Ｄｑ及ｂ的变化形态却存在着差异，大地震可能发生在Ｄｑ及ｂ值均降至最低时，也可能发生在Ｄｑ及ｂ值下降后又回升之时，还可能发生在Ｄｑ回升而ｂ值仍保持最低时。本着重对Ｄｑ及ｂ值的临震变化特征及其个体差异从非线性的角度作了物     

有序性分析与新疆7级强震预测

自然数可以视为反映世界客观本质的一种重要秩序，即信息，它不因加法处理而失真［１］。强地震在一定的时空范围内重复出现的现象称为有序性。自１７１６年以来，新疆及其邻区７级以上强震在时间上具有良好的有序性，有些强震在空间上亦表现出一定的有序性。强地震时间间隔值以６０、３０、４１、１９和１１年占据主导分布，并且相互之间关系密切。根据强震活动的有序性结构可进行预测：该地区未来Ｍ≥７强震可能发生在２００４年和２０１５年前后。     

前兆异常的非线性识别与地震危险地点的判定

利用多种描述复杂现象的非线性方法处理了多台多项多年的前兆观测资料，通过“场”、“源”特征差异性的对比求得地震危险地点是一个能量“振荡”型积累的地区，具体表现为它是在前兆异常演化过程中出现的异常从属度最高、自相似性变化最大、前兆分维数下降最多的地区，而且还是在地震活动过程中出现的一个熵值相对较低的地区。研究结果还表明，震中位置的不确定性随着发震时刻的逼近而不断减弱     

长江三峡及邻区地震活动的灰色预测

根据历史地震记载和现今地震观测数据，运用灰色系统理论，建立了长江三峡及邻区下一个地震活跃期及活跃期内可能发生的最大地震的震级的灰色预测模型。预测结果表明，下一个地震活跃期将持续７９ａ，活跃期内的最大地震震级不会超过５．２级。这对三峡地区地震问题的评价与防患提供了重要的依据     

FD─1型多功能防盗报警器

地震监测设施点多面广，被盗、被破坏的情况时有发生，直接和间接的经济损失十分严重。由此引起的仪器停记，造成资料中断的损失则无法用金钱计算、针对此问题，我们运用模糊控制技术技术，研制开发了ＦＤ－１型多功能防盗报警器。它通过检测来访者的文明程度，采取一系列相应的反击措施：即自动打开室内灯光、电视机、录音机等，造成室内有人的假象；对不知趣者给予警告、警铃……直至发出＂有电危险，请勿靠近＂的警告和电击（无生命危险），达到御敌于门外之目的。该报警器不仅适用于地震台站，也广泛用于各企业事业单位和家庭防盗等。