ANALYSIS OF SPHERICAL FUNCTION SPECTRAL STRUCTURE OF THE NORTHERN HEMISPHERE 500 HPA MONTHLY MEAN HEIGHT*

Study is undertaken of spherical function spectral structures of long-term mean and anomaly patterns of the Northern Hemisphere 500 hPa monthly mean geopotential height together with the seasonal and interannual variations investigated.Results show that they are marked by low dimensions and low orders,and the mean and anomaly fields can be described in terms of 20 and 50 spherical function components,respectively.     

多层基础隔震房屋结构在水平地震力作用下的振动传递

文章将周期结构原理与导纳方法结合起来，分析了带复合结构单元的有阻尼的有限周期系统的波传播和振动特性，得到了有限周期结构自振频率的一般表达式。     

Field verification of a theoretical model to predict the dynamic response of a soft clay deposit

A 40-m thick clay deposit was subjected to sinusoidal excitations using a foundation block and an eccentric mass type vibrator. The response of the foundation block and the surrounding soil was measured using geophones inside the soil and on the surface. The phase shift between the excitation signal and the response signal, the accelerations of the foundation block and the particle velocities in the soil are compared with those obtained from a frequency-dependent numerical model based on the exact analytical solution for the boundary value problem of a rectangular foundation resting on a linear elastic halfspace.     

闽台铲状活动断裂

福建台湾大型铲状活动断裂系在深部(深5—100km)构成一系列向东倾斜、倾角为4°—10°的滑脱面,在近地表利用老断层的重新活动,形成NNE与NW向网格交叉的高角度断层。活动断裂系的地震能量释放主要集中在台湾东部。推断现代构造应力场的最大主压应力方向是NW—SE向,缓倾斜、向西撒开呈扇状特征。断裂系中各断裂的滑动速率不同,东大西小。     

区域航空γ能谱场地球化学解释及预测方法的探讨

本文以“铀矿区域评价准则”为依据,试用因子分析主成分比值法,铀对钍(钾)的区域相对场法和铀成矿有利指数法,对我国YW-10和YW-10B两个测区的区域航空γ能谱场进行了地球化学解释及预测方法的研究,与已知矿区660测区从宏观上做了对比分析,并研究了γ能谱参数在走向长270km,宽50—70km空间上的分布变化规律。研究结果表明,这些方法对了解成岩时原始铀的分布及后期铀的地球化学活动规律,估计成岩、成矿阶段铀源岩可能提供的生铀量,识别铀成矿有利地区是有用的。     

A study of tropospheric wave disturbances over India in winter

The wave disturbances in the troposphere over north and central India during winter when the subtropical westerlies prevail in the upper air over the area have been investigated by power-and cross-spectrum analysis. The power-spectrum study revealed the existence of basically two systems of periods 10.0–12.5 days and 4.5–5.5 days in the middle and upper troposphere. Both the long-and short-period systems have been found to be propagating eastwards at rates 5° and 10° long./day respectively. In both the cases lower temperatures are found to the east of the troughs. It is also noted that these systems build up the meridional temperature gradient and hence strengthen the upper tropospheric westerlies. Synoptic study of the transient systems is presented.     

Three-dimensional elastic wave scattering and diffraction due to a rigid cylinder embedded in an elastic medium by a point source

The formal solutions of displacement field to the problem of elastic wave scattering and diffraction due to an infinitely long rigid cylinder embedded in an infinite elastic medium by an impulsive point source have been obtained in the integral form. The integrals for the reflected and the diffracted waves both in the shadow zone and in the illuminated zone are evaluated asymptotically for the early time motion by the Reisdue-Cagniard method and the Saddle-point-Cagniard method.Numerical results of the diffractedP, S andPS waves at a fixed circum-distance from the surface of the rigid cylinder show noticeably that (1) the energy partition for the diffractedS wave is small in comparison with that for the diffractedP wave, (2) the wave form of the diffractedS wave is broader and more diffused than that of the diffractedP wave, (3) the direction of the radial motions of the diffractedP andS waves varies as a function of the observational point, and (4) the energy partition for the diffractedP wave is much smaller than that for the direct or the reflectedP waves.This paper has been presented at the 46th Annual International Meeting of Society of Exploration Geophysicists in Houston, Texas, Oct. 28, 1976.     

璜山金矿找矿模式及应用

诸暨璜山金矿是除治岭头以外浙江省第二金矿,它的找矿模式为"三高两低一复合"的找矿模式,即高金晕、高极化率、高磁场跳跃、低电阻率、低电位和北东断裂与北东东断裂复合处是成矿最有利部位.在其附近仍有类似成矿部位,有望扩大远景.     

漫湾水库蓄水前后库区地震活动性与构造应力场分析

对漫湾水库蓄水诱发地震作了分析，结果表明，蓄水后库区小震频次明显增加，近距离地震明显增多，在蓄水首次达到高水位和由高水位突降至低水位时，诱发了最强地震。表明蓄水对库区构造应力场产生了影响，使得局部应力场较区域构造应力场作用方向出现明显偏转，作用方式发生改变，呈现较大的垂直作用效应，节面错动出现较大正倾滑动分量。     

双节点有限元模拟直立走滑断裂地震位移场

结合位错理论和有限单元法，对介质横向不均匀性引起的直立走滑断裂地震水平位移场不对称性进行了数值模拟研究。结果表明，断层两侧介质泊松比和弹性模量的横向不均匀性，均可以引起直立走滑断层同震破裂及地震位移场的不对称性，其中，断层两侧介质的剪切模量比(刚度比)对直立走滑断裂地震位移场不对称性起主要作用。