大凌河桥抗震分析     

陆鸣  于莉 《东北地震研究》1996,12(2):58-68

本文按有关规范的要求，结合大凌河桥的实际情况，分别计算在地震烈度为Ⅶ、Ⅷ、Ⅸ度情况下的周期，应力和位移等有关参数，给出了随桥架设的输油管线对桥体地震反应的影响程度，计算结果表明，在上述三种烈度情况下，桥体的破坏情况有所不同。  相似文献   

北部湾地震的震源机制及地震地质条件   总被引：3，自引：0，他引：3  

尹克坚  吴时平 《华南地震》1996,16(3):77-81

对北部湾地震的震源机制解和地震地质条件进行了详细分析，认为靖西－崇左断裂带过震中的北北西向断层为发震断裂，四会－吴川断裂带过震中的北东东向断层为控震构造，震源构造应力场的主压应力方向为北西－南东向，发震断层的活动方式既有垂直差异运动又有走滑运动。  相似文献   

自流井水位响应能力与水柱高度关系的分析   总被引：4，自引：0，他引：4  

张子广 《地震》1996,16(3):284-290

分析了万全等４口自流井水位阶变、固体潮幅度与水柱高度的关系。结果表明，当含水层所受应力状态不变，水位观测条件相同时，水位阶变、固体潮幅度度与水柱高度有正相关系。  相似文献   

大同－阳高2次地震前长治电感地应力的异常特征     

白晓勤 《山西地震》1996,(1)

大同－阳高２次中强地震前，长治电感地应力曾出现明显的趋势异常和短临异常。本文就长治地应力的观测条件以及地震前后的异常特征进行了分析研究，认为对于山西地震带北部地区的地震监测预报有参考价值。  相似文献   

运城盆地的现今构造活动及现代地壳应力场的基本特征   总被引：1，自引：0，他引：1  

刘巍  安卫平  赵新平 《山西地震》1996,(2)

大量震源机制解结果表明，运城盆地存在以水平拉张为主要特点的局部小区域应力场，盆地北部水平挤压分量占优势。这些特点不同于山西断陷带其它诸盆地局部小区域应力场的特点。由这些震源机制解结果中所有Ｐ轴、Τ轴做出的运城盆地的平均应力场，与华北区域地壳应力场和山西平均应力场的结果基本一致。说明运城盆地在宏观上、整体上仍严格受华北区域应力场的控制，其局部小区域应力场也是在华北区域应力场范畴内活动  相似文献   

Seismic monitoring of explosions: a method to extract information on the isotropic component of the seismic source     

P. Campus  D. Fäh 《Journal of Seismology》1997,1(3):205-218

The design of a monitoring system for detecting explosions is a very topical problem, both for routine data processing at seismological observatories as well as for the monitoring of a Comprehensive Test Ban Treaty. In this framework it is desirable to have the possibility to quantify the presence of the isotropic component in the seismic source. For this purpose a method is presented, which is based on waveform inversion for the full moment tensor retrieval. The method inverts either full waveforms or separate seismic phases and returns the mechanism and time history of a point source. Moreover, it allows to redefine the hypocentral depth of the event and, in a simplistic way, to optimize the structural model as well. In order to model strong laterally heterogeneous structures, different pairs of structural models can be used for each source-receiver path. The source is decomposed into a volumetric part (V), representing an explosive or implosive component, and into a deviatoric part, containing both the double couple (DC) and the compensated linear vector dipole (CLVD) components. The method is applied to an area in central Switzerland and to the network of the Swiss Seismological Service. The events of interest include both earthquakes and explosions. Despite some modelling inadequacies of the source-time function, the explosions can be well identified with the inverted isotropic component in the source, as long as the number of stations used for the inversion is larger than three. The results of the inversion are better for large epicenter-station distances of the order of 40–90 km.  相似文献   

强震空带现象机制和应用研究   总被引：1，自引：0，他引：1  

夏玉胜  梁子斌  孙洪斌  杨丽萍  蔡红卫  任铁生 《高原地震》1997,(1)

对中国大陆地震的空间分布进行了仔细的探讨，发现6级以上强震在西部（东经105°线以西）有三组近似是对称分布的空带现象，每组平行空带相邻带间距为5°，带宽约为1°；而东部则有两组NE、NW向空带将其分割成若干强震块体，相邻空带宽约700km，带宽约为150km。6级以下地震在空间上几乎随机分布。理论推导证明：强震空带现象其实质为一些不连续块状分布的强震区在空间的有序排列，且控制东西两部分构造运动的构造波波长均约1000km，并在同一机理下还统一地解释了强震等间距及构造带等间距现象。应力场反演表明，大陆西部受三组主次不同的边界力源作用。在研究过程中还发现气、油等轻而易于流动的物质的聚集区多分布在强震空带内，而金属矿藏多分布在强震块体内，同时从空带分布图即简单的地震危险区划图上可以看到，千百年来已发展建设成的大型城市多位于“安全岛”内。  相似文献   

地震前应变、应力测量异常特征研究   总被引：1，自引：0，他引：1  

赵淑平  王梅  魏焕 《高原地震》1997,(2)

据震例资料显示应变、应力测量异常形态与区域应力场增强失稳状态相关。主要特征：1．震前主应力方向发生明显偏转并指向震中区域；2．临震前应力测量异常显示四象限空间分布，张、压区域与震源机制解有明显相关性；3．异常形态与岩石破裂实验数值模拟结果有较好的一致性。  相似文献   

On the resolution of the isotropic component in moment tensor inversion   总被引：1，自引：0，他引：1  

H. Dufumier  L. Rivera 《Geophysical Journal International》1997,131(3):595-606

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A method of estimating the stress exponent in the flow law for rocks using fold shape     

Labao Lan  Peter J. Hudleston 《Pure and Applied Geophysics》1995,145(3-4):621-635

On the basis of experiment and theory, we expect rocks to deform in a linear fashion when diffusive processes control deformation, and nonlinearly in most other situations. The geometric characteristics of buckle folds in layered materials are dependent on rheological parameters, and in particular depend strongly on the stress exponent,n _L , of the stiff layers involved. Thus, information about the deformation rocks have undergone and their rheological state during deformation can be obtained by studying fold shapes and strain distributions. This is important because there is uncertainty in extrapolating laboratory-derived flow laws to the very slow natural strain rates and large strains found in nature.We have studied the development of buckle folds in linear and nonlinear materials using finite-element modeling, and interpolated the numerical results to construct plots relating several geometric parameters to variations in power-law exponent,n _L , and viscosity ratio,m, of layer to matrix. Such plots allow for a comparison of the results of numerical models with data for many natural and experimentally-produced folds, and there is consistency among the data for folds produced in physical models, using both linear and nonlinear materials and the numerical simulations. data for folds from the Appalachian Mountains, the Alps and elsewhere, however, suggest high values ofn _L in the flow laws for a number of rock types. The unexpectedly high estimates ofn _L suggest that other factors, such as strain softening or anisotropy, may influence fold shape, and thus complicate the estimation of the rheological properties of rocks.  相似文献