The connection of geodynamics with seismicity patterns

When a study is to be made of seismic risks, the present-day geodynamic conditions are of fundamental importance: Earthquakes do not happen by themselves, they do have a cause. The cause of earthquakes is that the tectonic stresses exceed a critical limit. The build-up of these stresses is conditioned by the geodynamic processes occurring in the region in question. A knowledge of the geodynamics characteristic of a region is therefore fundamental for seismic risk studies. The general methodology for making such a geodynamic study is based on the entire set of manifestations of the plate-tectonic conditions of that region: these include the mechanism of earthquakes, the stresses observed in mines, the orientation of surface joints and even the direction of river valleys. Examples of geodynamic studies and their bearing on seismic risks are shown from various areas of the world, notably from China, India, and Colombia.     

我国首次发现的钠砷铀云母

我国首次发现的钠砷铀云母产于新疆某铀矿床氧化带。它实际上是钠砷铀云母的含钾变种。与产于苏联的钠砷铀云母比较,晶胞参数稍大,比重稍小,在长波紫外线照射下发黄绿色中等强度荧光。     

对苏联固体镭源的检定

本文采用电离法(平板电离室装置)对英产镭源和苏联产镭源进行了研究,找出了两种不同当量壳镭源之间的相关关系,解决了按照国际镭源标准对苏联产镭源含量的检定方法。     

山区年、月平均温度推算方法的研究

本文提出了山区年、月平均温度空间分布的推算方法,并提供了相应的小地形温度订正值。该方法在福建省沙溪流域山区实际应用的结果表明,能有效地揭示山区年、月平均温度空间分布的宏观与微观变化,效果满意,精度较高。     

上海地区深部构造特征和地震活动趋势探讨

本文介绍由重磁资料计算上海地区居里面、莫霍面、均衡重力异常及地幔流应力场的方法和成果,并在对成果初步分析的基础上,探讨了深部地质构造特征及其与地震活动趋势的关系,其中着重讨论了居里面及其与地震活动的关系。文章最后提出了对上海地区地震活动趋势的几点认识。     

冀中拗陷古潜山油田水化学研究

冀中拗陷油气田87%的储量产于海相碳酸盐岩古潜山中,在油气生成、运移、集聚和散失的过程中地下水起了重要作用。本文根据50个试样的水化学分析资料,运用对应分析方法对冀中拗陷古潜山油田水进行了分类并初步探讨了水化学成分演化与油气藏形成的关系。     

Subsoil zoning of Mexico City using qualitative relationships between soil strength and electrical resistivity

Summary The seismic events occurring on 19 and 20 September 1985, whose epicentre was located in the coastal region of Michoacan, Mexico, produced tremendous damage in Mexico City. As a result of these losses the civil authorities of the city decided to study and evaluate the mechanical characteristics of the subsoil. To achieve this, it was necessary to drill several boreholes to obtain needed geophysical and geotechnical information. The geophysical method of electrical resistivity was the most appropriate to the research. This method enabled us to understand the structure and soil characteristics of the Mexican Valley.     

Preliminary results of seismic hazard assessment in the Sannio-Matese area of Southern Italy

The seismic hazard in the Sannio-Matese area has been worked out by a modification of the McGuire (1976) computing programme, taking into account the influence of nine potential seismic source zones.The method uses truncated-quadratic intensity-frequency distribution and azimuth-dependent intensity attenuation derived from isoseismal maps for each of the seismogenetic sources. A new modification has been introduced to take into account different decay of the intensity in the near (to VIII degree) and far (from VIII degree) field.Different assumptions about maximum possible intensities and truncation of intensity-frequency laws are used to evaluate the effects of the uncertainties on the computed hazard at high intensities. Intensities associated with different level of annual probability are computed for five test sites in the considered area. Maps displaying the expected intensity for a mean return period of 500 years (pa 0.002) are presented and compared with observed intensities.Presented at the XXIst General Assembly of the European Seismological Commission, Symposium on Methods of Seismic Hazard Assessment in Europe, Sofia, 23–27 August 1988.     

Estimation of seismic hazard parameters in TERESA test areas

A general overview of some of the problems involved in earthquake catalogue handling is given as part of the works carried out into the ESC/SC8-TERESA project related with the seismic hazard assessment in two selected test areas: Sannio-Matese in Italy and the northern Rhine region (BGN). Furthermore, the necessary input data to be used in the calculation of seismic hazard has been obtained, including earthquake source zones and their seismic hazard parameters.The importance is pointed out of detailed analysis of seismic catalogues, mainly in relation to the use of aftershock information, the historical records of the region, and the possible temporal and spatial variation of seismicity, which could have an important influence on short-term hazard assessment.