Earthquake engineering in China

The development of earthquake engineering in China is described into three stages. The initial stage in 1950’s – 1960’s was marked with the initiation of this branch of science from its creation in the first national 12-year plan of science and technology by specifying earthquake engineering as a branch item and IEM was one participant. The first earthquake zonation map and the first seismic design code were soon completed and used in engineering design. Site effect on structural design and site selection were seriously studied. The second stage marked with the occurrence of quite a few strong earthquakes in China, from which many lessons were learned and corresponding considerations were specified in our design codes and followed in construction practice. The third stage is a stage of disaster management, which is marked by a series of government documentations, leading by a national law of the People’s Republic of China on the protecting against and mitigating earthquake disasters adopted at the meeting of the Standing Committee of the National People’s Congress of the People’s Republic of China in 1997, and then followed by some provincial and municipal laws to force the actions outlined in the national law. It may be expected that our society will be much more safer to resist the attack of future strong earthquakes with less losses. Lastly, possible future developments are also discussed.     

山西省草地资源及合理利用

对山西省草地的类型、产量、质量以及利用现状等方面进行了比较分析，证实山西省草地资源丰富而且质量较好．山西省草地可分为六个生态类群，按草地质量可分为五等，按草地产量可分为八级．目前，山西省草地的利用存在很多问题，如缺乏科学的经营管理，对草地进行掠夺式利用等，针对此现状，提出了草地资源合理利用的对策，应该采用草地建设新技术，实施科学管理．     

MDCB型地震前兆监测仪的临震信息浅析

应用震前电磁波异常信息进行地震短临预报研究有着重要的意义,大庆地震台经过近两年多的观测及实际震例验证,基本说明了ＭＤＣＢ型地震前兆监测仪监测的时变曲线图、日变曲线图等七种图件与地震三要素密切相关的规律性以及使用ＭＤＣＢ型地震前兆监测仪资料进行地震短临预报的可行性和科学性。     

Modern hot spring geochemistry at the Tanlu fault and Jiaoliao block in eastern China

The δD, δ¹⁸O values of the hot springs are always more negative than those of the local cold springs. The main cause for the ocrurrence is physically isotope fractionation during the deep circulating process of the groundwater. The relational expression between the δD, δ¹⁸O values and the maximum circulating depths of the groundwaters is given. The gases escaped from the geothermal fluid are mostly crust-derived gases in the studied area. The compressive structure of the Tanlu fault could extend to the deep crust, and basically stop the ascent of deep-seated gases towards the surface. Project supported by the National Natural Science Foundation of China (Grant No. 49373165)     

The CO2 Discharge in the Boundary Fault Areas of the Sichuan-Yunnan Block and Its Sources

A large number of CO2 springs outcrop along the boundary faults of the Sichuan-Yunnan block and in their neighboring areas.These springs are of a roughly similar distribution as the epicenters of strong earthquakes since 1900.This similarity indicates that the CO2 discharges could be directly related to the modern seismic activity in that area.The evidences of stable carbon and oxygen isotopes indicate that an overwhelming majority of the CO2 released from modern active faults is derived from the deep earth crust.There are 2 main mechanisms of CO2 discharge.Modern active faults are able both to produce directly a lot of CO2 due to thermodynamic metamorphism and to provide passages for the CO2 constituent coming from the lower crust or upper mantle.By continuously monitoring the dynamic changes of CO2 discharges,it would be possible to obtain the information of earthquake precursors that reflect the physical and chemical changes of the earthquake sources.     

提高航测资料精度和图件质量的数学方法

虚拟切割线调平法是一种提高航测资料精度和图件质量的新的数据处理方法。该方法以误差理论为基础，根据场的分布理论，利用多项式数据拟合对测量数据进行分析、处理，以便消除迭加在测量值中的系统误差，从而达到消去因误差引起的相邻测线间场的水平的不一致以及出现在等值图上的波纹现象的目的。该方法已成功地应用于某测区的高精度构造航磁资料的处理。     

我国华中地区稻田甲烷排放特征

本文主要讨论地处我国华中水稻生态区的湖南红壤稻田的CH4排放特征。稻田CH4排放的日变化都有一致的规律，即在下午16:00左右出现最大值；CH4排放的日变化幅度与天气条件和水稻植物体有关；CH4排放的日变化与温度日变化的相关性很好（R>0.90）。早稻和晚稻的CH4排放季节变化规律有明显的差别，这主要是由于早、晚稻水稻生长期间的天气特别是空气温度变化的差异引起的，早稻CH4排放率在水稻生长中期（6月）略大，而晚稻在水稻移栽后几天内CH4排放就达到整个季节中的最大值，以后随时间逐渐降低；缺水会使CH4排放率明显降低，而且在重新灌水后相当长时间内CH4排放率没有回升；CH4排放在全有机肥的田中最大，然后依次是常规施肥、全沼渣肥及化肥田；尿素、氯化钾和复合肥的多施可降低稻田CH4排放率；不同施肥田中CH4排放率的温度效应不同；施肥是控制CH4排放的一种可行手段；在整个晚稻生长季节中瞬时CH4排放率与瞬时温度呈明显的指数关系；在1991年双季水稻生长季节中，稻田中CH4的排放量为67.96 g·m-2，其中早稻的CH4排放率为0.36 g·m-2·d-1，晚稻为0.48 g·m-2·d-1。     

Methane Production, Emission and Possible Control Measures in the Rice Agriculture

In the rice field methane is produced in the soil layer with depths of 2-25 cm. The vertical profile of methane production rate in the paddy soil during the water covering period differs from that in the paddy soil in dry phase. Only a small part, about 30%. of the produced methane is emitted to the atmosphere through rice plant, air bubbles, and molecular diffusion. Therefore, the methane emission rate from the rice field depends not only on the methane production rate in the soil, but also on the transport efficiency of the rice plant, air bubble formation that in turn depends on the production rate, and molecular diffusion.Field measurements show that methane emission rates from a particular rice field have very large diurnal, seasonal and interannual variations, which are related to soil characteristics, water regime, farming procedure, local climate, and rice growing activities. The relationship between the methane emission rate and the above mentioned factors is very complicated. The emission rate     

川滇块体边界断裂的CO2释放及其来源

川滇块体边界断裂沿线及附近地区有大量的CO_2泉出露,其分布与1900年以来强震震中的分布大体一致,这表明该区CO_2释放可能与现代地震活动有直接关联。稳定碳、氧同位素证据表明,现代活动断裂释放的CO_2绝大部分来自地壳深部,并有两种主要的释放机制。现代活动断裂既可以直接产生大量的热动力变质成因CO_2,又可以作为通道释放来自下地壳甚至上地慢的CO_2组分。连续监测深源CO_2的释放动态有可能获得反映震源物理化学变化的地震前兆信息。