华北地区强震前的森下指数异常

文中计算了华北地区最近２０ａ来的次Ｍｓ≥５．８地震前的森下指数，结果发现，在正常情况下，森下指数Ｉｓ变化平稳，而到震前０．５～２ａ突然出现几倍于正常水平的上升变化，作者还将森下指数由空间域延伸到时间域，也取得了较好的效果，时间窗的长度，震级下限及网格尺度选取是影响森下指数结果的３个重要因素，只有三者组合得当才能获得好的效果。     

森下指数在地震预报研究中的应用

把可以反映地震空间分布状态的森下指数进一步应用于地震预报研究中，所得结果表明，在大地震发生前数年，森下指数随网络线度的变化曲线Ｉδ（ｌ）要出现一定的中长期异常变化，但其异常形态随地区不同而可能有一定差异。对于日本的Ｍ≥７级海域地震，震前３￣６年Ｉδ（ｌ）曲线由正常期的Ｃｂ型转变为异常期的Ｃａ型。对于中国西部地区和华北地区的Ｍ≥６级地震，震前２￣３年Ｉδ（ｌ）曲线分别由正常期的Ｃａ型转变为异常期的Ｃ     

1982年朝鲜殷栗5.5级地震异常综述

辽宁省自７０年代建成监测台网以来，发生几次中强地震，其中包括邻近地区朝鲜境内的天摩山５．７级地震和殷栗５．５级地震，为了更多地挖掘我省中强地震异常信息，更好地寻求预报指标，笔者收集了大量资料并做了有关计算，发现该地震前，辽东半岛及邻近海域地震异常明显，宏观异常丰富，其主要异常标志类似于海城，营口，彰武中强地震，因此，殷栗地震异常总结对于确定我省中强地震预报指标具有实际意义。     

宁夏及邻近地区中强地震前后小震综合断层面解分析

我们对宁夏及邻近地区中强地震前后小震综合断层面解进行了不同时间段及分区的研究，研究结果表明宁夏几次强地震前，小震综合断层面解的Ｐ轴取向有明显的变化，有的偏离区域正常构造庆力场的Ｐ轴主压应力场的方向，有的求不出结果。震前显示异常的最长时间近四年之久。显然，前的这种变化对预报未来中强地震的发生是有参考意义的。同时还表明，中强地震后区域应力场有调整过程。     

沐川5.7级地震及马边,雷波地震带的地震活动度异常特征

本文用地震活动度研究了马边、雷波地震带１９９４年１２月３０日沐川Ｍｓ５．７地震，并以该带历史地震作为比较，探讨了中强地震发生前地震活动度的异常特征。得出了中强地震发生前地震活动度具有可识别性的认识。     

中国大陆多种前兆异常研究及强震的尝试性预测

强震震源周围地电、水化学、水动态、地应力和地形变等５种前兆短临异常 时空演化取决于主要活动构造和强震发震机制;远场异常时空演化与主要活构造有 关,不同活构造上异常时间演化有差异性;在特定年份１ａ尺度地电阻率异常显示异 常高潮期,Ms≥５．０地震能量达到１次以上Ｍｓ７．０强震能量的年份与异常高潮期 同步或滞后１ａ,二者与地球自转加速年份基本对应。根据两方面的研究结果进行了 实际预测检验,在预测区间和预测时间段（０．５ａ或１ａ）内发生强震、中强震１０次,其 中７次地震地点基本准确,３次地震地点较为准确。     

华北地区中强地震前调制地震异常特征

利用调制地震方法对华北地区１９７３年以来发生的２４个ＭＬ≥５．５地震前地震调制比、地震调制比异常面积、调制地震条带和调制地震频度的异常变化进行分析,对异常类型进行分类。分析结果认为,华北地区ＭＬ≥５．５地震前地震调制比和异常面积随时间进程的起伏、调制地震频度震前数月的突然增大以及调制地震条带异常图象是显著的异常变化,可以用于对中、强地震的中期预报。     

1989年大同——阳高地震及其前兆特征

１９８９年１０月１８～２３日在大同—阳高地区发生了一组中强地震，最大震级为Ｍｓ６．１。这次地震是在华北地区１９６６～１９７６年强震活动高潮之后，在连续１０ａ无６级以上地震活动的平静背景上发生的。由于本区观测台网较为密集，因而在震前观测到较为丰富的前兆现象。通过对这些前兆特点及其发展过程的研究，发现在大同—阳原盆地加速下降后（震前２～３ａ），在前兆中长期—中期阶段，前兆异常由震源区向远区扩展（１３５→３３０ｋｍ），在前兆异常的短期阶段，大部分异常从远场逐渐向孕震区收缩。有限元模拟计算结果表明，大同—阳高地震的孕育是一个长期的过程，由于大同—阳高孕震区地壳内存在断层面的障碍体或硬包体，它们具有较强的抵抗变形的能力，从而使得该区的应力随时间不断积累，在此过程中，周围地震的发生对其应力场具有不同程度的影响，有的使其增加，如渤海地震，有的使其减小，如邢台地震，到１９８５年前后，大同—阳高地震的孕育基本成熟     

综合异常指数的进一步研究与应用

从指数分布函数出发对于基于多种地震前兆异常的综合异常指数进行了较为深入的探讨, 综合异常指数具有直接的数学来源, 蕴涵着明确的物理意义:将失效分布函数中的失效率分段取值, 并与地震研究中某种预测手段或方法所处的状态联系起来, 即取为某种预测手段或方法在某研究考察时段内的异常隶属度, 产品的失效则意味着该预测手段或方法出现了异常,得到异常指数;对其进行加权, 得到单项异常指数;对单项异常指数进行综合后即得到综合异常指数。综合异常指数包含了所研究的所有观测手段或方法所蕴涵的地震信息。最后将其具体应用于宁夏震情监视区, 进行了预测检验。发现对于1970 年后发生在宁夏及邻区的9 次中强地震事件, 综合异常指数均有较好的对应。     

南黄海及沿岸地震活动时空动态扫描特征

从中强震成组孕育出发,研究了南黄海及沿岸地区地震活动时空动态图象扫描特征,探索了该区地震危险性预测的有关问题。结果表明,该区２０多年来４级地震活动总休上呈相对平稳状态,但在不同时段则出现不断演变迁移的４级地震局部集中区及低ｂ值区等异常区域,５～６级中强地震大都发生于异常区的边中附近;异区内４级地震累积频度往往呈非线性指数加速,中强震发生于４级地震非线性指数加速的后期或其后的异常平静期中。这种地震活     

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.