东秦岭与华南加里东褶皱带原地—准原地改造型花岗岩特征

东秦岭与华南加里东褶皱带具有不同的岩石建造特征,两褶皱带的改造型花岗岩类之间也存在着明显不同的化学成分特征。研究表明源岩在很大程度上决定了改造型花岗岩的特征。     

Analytic solutions to long's model: A comparison of nonhydrostatic and hydrostatic cases

Summary In this paper, analytic solutions of the nonhydrostatic and hydrostatic forms of Long's model were obtained under two different sets of vertical boundary conditions: The first uses a sumusoidal obstacle at the lower boundary and a rigid-lid top for the upper boundary. The second set applies an isolated obstacle of the Witch of Agnesi type at the lower boundary, while still using a rigid lid at the top. Following the solution evaluations, comparisons between the nonhydrostatic and hydrostatic solutions were processed in order to describe several influences introduced by using the hydrostatic assumption in this model.Through comparisons we have found that, in the case of a sinusoidal lower boundary condition, the hydrostatic solution is obtained as the zero mode of the nonhydrostatic solution. The influence of the hydrostatic assumption on the model solution is trivial in this case. When an isolated lower boundary condition is applied, however, the solutions illustrate dramatic differences, showing the significance of the effect of hydrostatic assumption on this model's solutions. These effects vary considerably with the model parameters as well. The comparison results also reveal that the realization of the hydrostatic assumption in this model's solutions is accomplished through the vertical boundary conditions used in the model evaluations.With 5 Figures     

积雨云中微物理过程的数值模拟——(二)阵雨、冰雹、暴雨的个例研究

用文(一)的微物理模式在一维时变动力学框架里模拟了江西阵雨云,75·8暴雨和张家口冰雹云。用实测探空作为输入,计算结果同实测的云降水和雷达回波特征相比,在很多方面相当一致。它展示了暴雨云的持续性和冰雹云的低降水效率等,表明了在这些云底较暖的积雨云中贝吉隆过程对降水作用不大,而暖雨过程则是启动降水的主要环节。     

Research on the regionalQ values of coda waves for the aftershocks in Luquan,Yunnan of 1985

Based on the scattering coda model by which local and regional earthquakes are interpreted (K. Aki, 1969), and using observational coda data of 68 aftershocks of the 1985 Luquan, Yunnan earthquake registered by the VGK seismographs installed at 12 stations in the Yunnan regional short-period network, theQ-values of coda waves are calculated respectively for 6 time intervals. It is observed that within the frequency range of 0.40–1.65 Hz of the observed data, theQ-values are closely related with the frequencies and the calculated codaQ ranges between 80–240 with the coefficient of frequency dependence η=0.45. The calculated source factorsB(f> _p) of the coda waves which indicate the scattering strength are mostly within the order 10^?23–10^?24. Areas with lowQ-values present high scattering. It should be noted that by comparing data obtained before and after the Luquan earthquake, clear changes can be detected in theQ-values measured at stations close to the epicentral region, and that theQ-values of the aftershock coda are less than about one half of the pre-shock values. It may be mentioned that the time-dependent regional variations of theQ-values might possibly bring about practical significance in earthquake prediction. Moreover, aftershock focal parameters are determined. Through discussions on the quantitative relations between the focal parameters, we get: 1gE=1.59M _L+ 11.335;E=(2.10 × 10^?5)M ₀; length of focal rupturea=0.40?0.80 km for 3.0≤M _L<5.0 events; stress drop Δσ=(6.0–130) ×10⁵ Pa. Through interpretation of the data, we have also learned the important characteristics that there is no linear relation between the stress drops and the earthquake magnitudes.     

勘探工程地质统计信息法

勘探工程地质统计信息法试图运用定量评价准则研究勘探工程,而定量评价准则是建立在矿体数学模型基础上。本文在最优勘探方案和最优工程位置选择方面作了一些研究。     

跟踪和预报雷达强回波运动初探

利用数字化天气雷达资料，针对强对流天气下的回波块，提取面积Ｓ、形状描绘子Ｒ和矩不变量Ｍ３个特征量，作为判别因子，对强回波块进行跟踪，然后作出回波移动预报。对７次降水过程的实测雷达资料试验结果表明：该方法的跟踪和预报准确率是令人满意的。     

北京地区气温诊断分析

本文讨论了北京地区百余年气温的变化特征，依据加法模型理论，提出了一种气候诊断和预测方法─—逐步回归多重因子方法，其优点在于将序列的周期因子、谱成分及外界气候振动因子同时引入回归模型中。这一方法，对单序列的气候诊断和预测具有明显效果。     

热流测量中垂向地下水运动干扰的校正方法

本文提出了一种地表热流测量中垂向地下水干扰的校正方法。并以江西萍乡和福建安溪的二个钻孔为例,说明了热流校正的具体过程。由于地下水对流传热的影响,垂向地下水渗透层内温度和热流随深度均呈指数分布。通过对钻孔测温数据的一维垂向Peclet数分析,可以确定渗透层内传导和对流热流分量以及热流的构成,从而得到未受地下水对流干扰的区域背景热流。这一方法不仅适用于渗透率结构均一的介质,也可用于水平层状介质。     

多元统计在大洋玄武岩同位素端元识别中的应用

应用因子分析的方差最大旋转和非线性映射方法对海洋玄武岩Sr、Nd、Pb同位素数据在多维空间中的数据结构进行了分析。研究表明这些数据在多维空间中呈五角形结构,并对应5个地幔端元:大西洋中脊玄武岩(DMM),圣埃伦那(HIMU),鲸岛(EMI),萨摩亚岛(EMII)和DS(EMIII).其中DS(EMIII)是本文新识别出来的一个地幔端元,它可能是重新进入地幔的具有较高古老放射成因Pb的下地壳物质。     

The Ground Deformation Disaster in the City of Tianjin Associated with the Tangshan Earthquake

In this paper,a study of the principal characteristics of the ground deformation disasters in the city of Tianjin caused by the Tangshan earthquake is based on the results from the recent remeasurements of the geodetic controlling network of Tianjin and from on-site investigations after the earthquake.These results show that only the ground deformation in the Ninghe and Hangu areas near the epicenter reflect directly the co-seismic crustal stress,while the serious ground deformation and the engineering earthquake damages in the urban districts of Tianjin are controlled to a great extent by the local engineering geological structures,showing a kind of secondary disaster.Several suggestions are also proposed in the paper concerning the counter-measures for reducing the earthquake damage in big cities.