国内外震情

国内外震情１９９５年１２月华北地区Ｍ＿Ｌ≥３．０地震动态１９９５年１２月份华北地区（３３．０”一４２．０”Ｎ，１１１．０”一１２５．０”Ｅ）范围内共发生从＞３．０地震５次（见下表），无尽级以上地震发生．与上月相比，本月华北地区的地震活动仍处于相对较低...     

1993年9月份首都圈地区M＿L≥2．0级地震

１９９３年９月份首都圈地区Ｍ＿Ｌ≥２．０级地震１９９３年９月份在首都圈（３８．０°—４１．０°Ｎ，１１３．０°—１２０．０°Ｅ）范围内，共发生１７次Ｍ＿Ｌ≥２．０地震，其中１２次２—２．９级地震，５次Ｍ＿Ｌ＞３的地震。震级最大的一次为９月２７日发生在...     

国内外震情

１９９７年１０月华北ＭＬ≥３．０地震动态根据国家地震局分析预报中心提供的资料,１９９７年１０月华北地区（３３．０°～４２．０°Ｎ,１１１．０°～１２５．０°Ｅ）共发生ＭＬ≥３．０地震１１次,无４级以上地震发生,北安河发生了两次３级以上地震（见附表）。...     

1988年云南澜沧－耿马大地震前地震活动平静的统计研究

本文根据大地震前包含异常活动时段的地震序列全过程可以看作是非齐次油松过程的理论，详细研究了１９８８年１１月澜沧－耿马大地震前（１９８０．１－１９８８．１０）澜沧到腾冲地区地震活动在时间和空间上的变化过程。结果表明：①１９８５年４月－１９８８年４月全区地震活动在空间上存在着明显的差异，其中澜沧向北延伸分别出现２１０ｋｍ的Ｍ≥３．５和１６０ｋｍ的Ｍ≥３．０的地震活动平静地段。因此，由南向北将全带划分为南区、中区、中′区、北区四个研究小区；②在包含主震和余震区的中区，主震前分别出现了持续时间长达４２个月（Ｍ≥３．５）和３２．５个月（中′区，Ｍ≥３．０）的异常地震活动平静，并在０．９９和０．９７的置信度水平上通过统计显著性检验；③与此同时，在南区却出现了长达４２个月（Ｍ≥３．５）的异常地震活动增强时段，其置信度可达０．９５。然而在北区，于１９８５年９月结束了长达５２个月的地震活动增强，置信度仅０．８５，显然它是受１９７６年龙陵地震余震活动的影响，因为该区正好包含龙陵地震的余震区。     

国内外震情

１９９８年５～６月份华北地区ＭＬ≥３．０地震动态根据中国地震局分析预报中心提供的资料,１９９８年５月份华北地区（３３．０°～４２．０°Ｎ,１１１．０°～１２５．０°Ｅ）共发生ＭＬ３．０以上地震９次,无ＭＬ４．０以上地震发生,其中最显著的事件是５月１７...     

1996年5月华北地区M_L≥3．0地震动态

１９９６年５月华北地区Ｍ＿Ｌ≥３．０地震动态根据国家地震局分析预报中心提供的资料，本月在华北地区（３３．０°～４２．０°Ｎ，１１１．０°～１２５．０°Ｅ）共发生ＭＬ≥３．０地震４次（见附表），其中最为显著的事件是５月４日的文安ＭＬ３．８地震。本月地震...     

1996年5月首都圈地区M_L≥2．0地震动态

１９９６年５月首都圈地区Ｍ_Ｌ≥２．０地震动态根据国家地震局地球物理研究所四室提供的资料，本月在首都圈（３８．０°～４１．０°Ｎ，１１３．０°～１２０．０°Ｅ）范围内，共发生ＭＬ≥２．０地震１４次，其中震级最大的为５月４日河北大城ＭＬ３．９地震。唐山?..     

1994年8月华北M＿L≥3．0地震动态

１９９４年８月华北Ｍ＿Ｌ≥３．０地震动态１９９４年８月份在华北（３３．０°─４２．０°Ｎ，１１１１．０°─１２５．０°Ｅ）范围内共发生Ｍ＿Ｌ≥３．０地震３次（见下表），无４级以上地震发生。本月华北地震活动水平偏低，三次地震全部发生在华北南部。山西和顺...     

1994年9月首都圈M＿L≥2．0地震动态

１９９４年９月首都圈Ｍ＿Ｌ≥２．０地震动态１９９４年９月份在首都圈（３８．０°─４１．０°Ｎ，１１３．０°─１２０．０°Ｅ）范围内，共发生Ｍ＿Ｌ≥２．０以上地震１１次，其中最为显著的是９月９日发生在河北卢龙Ｍ＿Ｌ≥３．２地震（见下表）。本月发生的２级...     

国内外震情

１９９８年７月份华北地区ＭＬ≥３．０地震动态根据中国地震局分析预报中心提供的资料,本月在华北地区范围内（３３．０°～４２．０°Ｎ,１１１．０°～１２５．０°Ｅ）,共发生ＭＬ≥３．０地震１３次,其中ＭＬ４．０以上地震５次（见附表）。本月地震频度和上月相...     

A Monte Carlo study of rainfall forecasting with a stochastic model

A procedure for short-term rainfall forecasting in real-time is developed and a study of the role of sampling on forecast ability is conducted. Ground level rainfall fields are forecasted using a stochastic space-time rainfall model in state-space form. Updating of the rainfall field in real-time is accomplished using a distributed parameter Kalman filter to optimally combine measurement information and forecast model estimates. The influence of sampling density on forecast accuracy is evaluated using a series of a simulated rainfall events generated with the same stochastic rainfall model. Sampling was conducted at five different network spatial densities. The results quantify the influence of sampling network density on real-time rainfall field forecasting. Statistical analyses of the rainfall field residuals illustrate improvement in one hour lead time forecasts at higher measurement densities.     

Earthquake Engineering and Engineering Vibration Aims And Scope

正This journal is established by the Institute of Engineering Mechanics(IEM),China Earthquake Administration,to promote scientific exchange between Chinese and foreign scientists and engineers so as to improve the theory and practice of earthquake hazards mitigation,preparedness,and recovery.To accomplish this purpose,the journal aims to attract a balanced number of papers between Chinese and     

Foreword

Destructive earthquakes have caused great damage in China and the United States and collapsing buildings havecaused many deaths and injuries. The field of earthquake engineering studies earthquake hazards, the occurrence ofearthquakes of various magnitudes, the nature of the ground shaking during an earthquake, the vibration of structuresduring earthquakes, the strengthening of existing structures and the design of new structures to be earthquake resistant,and finally, how to cope with earthquake damage and restore a city to normal functioning. Such efforts are in progressin both countries, but unfortunately, the language barrier interferes with the free flow of information between China andthe Untied States. It would be mutually beneficial if some means could be developed to promote the exchangeof information across the Pacific Ocean. This new journal has been established for this purpose and its success willbe an important step in promoting earthquake engineering in China and the United States.     

WORLD ASSOCIATION FOR SEDIMENTATION AND EROSION RESEARCH(WASER)

正President:Giampaolo Di Silvio,Italy Vice Presidents:Ulrich C.E.Zanke,Germany Zhao-yin Wang,China The World Association for Sedimentation and Erosion Research(WASER),inaugurated on Oct.19,2004,is an independent non-governmental,non-profit organization.The mission of WASER is to promote international co-operation on the study     

Enhancing remote sensing research on global change to improve our understanding on Earth system processes

正Global Change includes climate change and other environmental changes caused by the joint interaction among various layers of Earth. From the positive side, global change provides new opportunities to human and other living forms on Earth. In the meantime, it creates tremendous challenges and negative impact. At present, the negative impacts have reached all primary processes of the global ecosystem and every aspect of human society, especially causing degradation of the ecosystem. For instance, intensive deforestation causes decline of biodiversity; global warming causes sea level rise and increases     

Solute concentrations in the lower niger river and the source rock contribution

Water quality analyses for the Niger River for the 1980/81 hydrological year are presented. The samples were collected from the main river at Lokoja, and from two main tributaries, the Kaduna and the Benue Rivers. Different water types were distinguished by the concentrations of major ions. The type Ca > Na > Mg > K - HCO₃ > SO₄ > Cl was represented at all stations during at least part of the year. Chloride was found to dominate the sulphate ion in the Kaduna and Niger, while the Benue maintained a higher concentration of sulphate relative to chloride all year round. Distinct patterns of seasonal variation in the ion concentrations were observed, particularly for the samples collected at Lokoja. Low ion concentrations were prominent during periods of high discharge, while low flow periods coincided with high dissolved ion concentrations. The contribution of rainwater to the total dissolved solids in the river waters was assessed indirectly using rainwater chemistry data from the Gulf of Guinea. The estimated rainwater contribution to the Lower Niger amounts to 5.15 mg 1^?1. Geochemical weathering calculations involving reactions of the four major minerals of granitic rocks - anorthite, biotite, albite, and K-feldspar - with carbon dioxide and water, can account for the average water composition of the Lower Niger. The proportion of the ionic components was also related to the occurrence of the respective element in the minerals.