Sandy desertification in the north of China

With the economic and social development, desertification exerted increasingly profound influences on natural environment and social development and attracted widespread attention of international communities. China, as one of the countries facing severe desertification problems, has witnessed some progress in understanding and combating the process of desertification through many years of hard work. Based on the experiences and research achievements, this paper briefly discusses the causes, developmental processes, damage assessment and control mechanism of desertification in the north of China so as to provide some basic experiences for the further study of desertification.     

Utilization of water resources,ecological balance and land desertification in the Tarim Basin,Xinjiang

Because of the human exploitation and utilization of water resources in the Tarim Basin, the water resources consumption has changed from mainly natural ecosystem to artificial oasis ecosystem, and the environment has changed correspondingly. The basic changes are: desertification and oasis development coexist, both “the human being advance and the desert retreat” and “the desert advance and the human being retreat” coexist, but the latter is dominant. In the upper reaches, water volume drawing to irrigated agricultural areas has increased, artificial oases have been enlarging and moving from the deltas in the lower reaches of many rivers to the piedmont plains. In the middle and lower reaches of the Tarim River, the stream flow has decreased, old oases have declined, natural vegetations have been degenerating, desertification has been enlarging, and the environment has deteriorated. The transition regions, which consist of forestlands, grasslands and waters between the desert and the oases, have been decreasing continuously, their shelter function to the oases has been weakened, and the desert is threatening the oases seriously.     

2001年四川省雅江-康定6.0级地震烈度考察及发震构造背景雏议

2001年2月23日四川省发生的6.0级地震，其宏观震中位于雅江县与康定县之间的高山峡谷地带．极震区烈度可达Ⅷ 度，Ⅷ 度区、Ⅶ 度区和Ⅵ 度区面积分别为180km2，1472 km2和3998 km2，等震线分布总体形态呈椭圆形，长轴近南北向．震区建筑物普遍受损，极震区山地灾害较为严重．初步分析认为，此次地震的发生与理塘断裂和玉农希断裂的长期活动有关，主干断裂活动造成的地壳应力调整和集中，最终在块体内部的次级断裂上释放而产生地震．      

上海数字强震观测网

上海市数字强震观测网是我国第1个具有一定规模的数字强震观测网，是上海市“九五”期间建设完成的，它由3部分组成；地面观测网，结构观测网和深井强震观测系统，每一部分都有不同的功能和目的，本文详细介绍该强震网的整个概况。功能及取得的部分观测成果。     

基于GIS与ANN耦合技术的地裂缝灾情非线性模拟预测系统——以山西榆次地裂缝灾害为例

现代地裂缝在世界许多国家普遍存在 ,已成为当今世界范围内的主要地质灾害之一。本文在详尽分析了山西榆次地裂缝的各个致灾因子的基础上 ,利用GIS技术建立了地质学意义上的专题层 ;然后采用人工神经网络技术构建出了地裂缝灾害活动性的评价模型 ,并建立了地裂缝活动性的评价系统 ,对榆次地裂缝进行了灾害活动性评价 ,为榆次市城建和国土规划等部门的正确决策提供了重要的科学依据     

国际地磁学与高空物理学协会和国际地震学与地球内部物理学协会联合科学大会及地震电磁研究进展

简要介绍了 2 0 0 1年 8月 1 9～ 3 1日在越南河内召开的国际地磁学与高空物理学协会 ( IAGA)和国际地震学与地球内部物理学协会 ( IASPEI)联合科学大会以及地震电磁研究进展 ,表明地震电磁前兆在地震预测研究中具有一定的实际效果与良好的研究前景。我们建议在不久的将来能在北京举办 IAGA,IASPEI和 IUGG(国际大地测量学与地球物理学联合会 )大会。这将促进我国的科技进步 ,有助于加强我国在国际科学界的地位与影响。     

Application of Dangerous Probability Function in Risk Estimation of Surface Rupture Earthquake：Taking the Lingwu Fault in Ningxi1 Region as on Example

Based on the fitting on paleoearthquake data of intra-plate regions in the northern part of Chi-na and giving a statistical model of time interdependence,the potential damage earthquakes in a definite future period and characteristics of present shocks along the Lingwu fault have been analyzed by using dangerous probability function and some new data concerned.We have in-ferred that the fault has entered a period that earthquakes will probably occur.There exists a potential danger that a strong earthquake with Ms7.0-7.5 will occur in 10-100a.     

The experimental studies on electrical con-ductivities and P-wave velocities of anortho-site at high pressure and high temperature

Introduction The measurements of the compressional wave velocity and electrical conductivity of minerals and rocks are of fundamental importance to look into the earths interior, including composition, geotherm, generation and distribution of fluids and melts. Hydrous minerals formed by metamatu-siom are abundant within the earth. Previous studies have been carried out on the dehydration effect on the electrical conductivity and wave velocity of rocks such as serpentine, amphibole, most of whi…     

河南豫北地震台网地区波速的探讨

为了解决河南豫北地区地震的定位问题 ,对豫北台网内的 10个典型地震 ,使用了 7个地震台站的资料 ,用波速比求出横波速度 ;用和达定位法 (有的同时使用高桥法 )进行了精确定位 ,求出震源深度 ;测量了震中至各台的震中距 ,以此反算出了纵波速度。通过计算 ,确定出了较为适合河南豫北地震台网地区的波速。     

河南郑州台数字化DSQ水管倾斜仪观测精度的评定

选取了河南郑州台数字化 DSQ型水管倾斜仪观测资料较好的 2 0 0 1年 10月 1日至 12月 31日的数据进行了分析处理 ,对该仪器的观测精度进行了评定。经计算 ,其北南向和东西向日飘移分别为 0 .0 0 0 7s和 0 .0 0 2 6 s,M2 的振幅因子为 0 .714 9和 0 .6 4 14 ,振幅因子中误差为 0 .0 0 5 5和0 .0 0 4 4。