考虑地基土液化影响的桩基高层建筑体系地震反应分析

本文建立了土体－结构体系地震反应分析的混合有限元法，并研究了地基土液化对地震反应的影响。本方法把土体－结构体系简化为一个完整的体系，该体系由梁（柱）单元、剪切杆单元、刚体单元、平面四边形等参单元与三角形单元、界面单元的任意组合来模拟。桩与上部结构材料视为线弹性体，土介质视为非线性材料。土的静应力－应变关系之间的非线性用邓肯一张模型来描述；土的动应力－应变关系之间的非线性和振动孔隙水压力对土的软化效     

我国现行抗震设计规范中场地评定方法的比较和评述

目前，我国抗震设计规范中采用的场地评定方法主要有两种：一是建筑抗震设计规范（ＧＢＪ１１－８９）采用的场地分类的方法，一是构筑物抗震设计规范（ＧＢ５０１９１－９３）和电力设施抗震设计规范采用的场地指数法。前者是把场地影响按照场地分类指标划分成若干场地类别，因此，确定的地震荷载是不连续的，跳跃变化的。后者是一种以模糊推论的综合评判方法导出的场地指数为指标进行连续评定的新方法，在这种方法里，场地性质的差     

华北北部地区2005年前地震危险性预测研究进展

综述了利用确定性和概率性相结合的预测方法，对华北北部地区２００５年前的地震危险性进行了概率预测研究。研究表明，该区在２００年前发生６级以上地震的概率为０．４５，其中涿鹿－怀来一带地区内每个计算单元中的发展概率最高，达到０．０２。     

发震时深浅构造相互作用导致横向断层致锁的有限元分析

本文利用三维有限元方法，研究和计算了大震发生前、发生时，发生后震源断层面与深部同面立接断层之间的相互作用以及发震后促使深部断层发生错动从而对震源区近场横向活动断层致锁的结果，得到以下结果：（１）临近大震前震源断层面端部调整单元下方的深部断层有较高的剪应力水平，造成震时对震源断层面发生底辟作用的条件，即调整单元区对应的深部断层单元首次满足破裂条件并发生破裂。（２）震源端部的调整单元和具有蠕能力的横向     

Crustal transit time monitoring using PKP

The arrival time difference for the AB branch of PKP from deep Tonga earthquakes is constant over years with a standard deviation of ±0.05 seconds at seismographs located 10 to 50 km from each other. If published travel time curves are used to calculate the relative residuals of PKP the standard deviation from the constant mean is improved by approximately 0.01 seconds for AB branch data. For the BC branch, standard deviations of relative travel times of ±0.06 seconds are reduced to less than ±0.05 seconds by calculating relative residuals. We conclude that changes of crustal transit time forP-waves could be resolved, based on careful PKP arrival time measurement at two or more neighboring stations if the changes exceed 0.05 sec and last for more than one year. The conditions for achieving this result are that PKP from Tonga earthquakes is clearly recorded, and that time-keeping is accurate. The data on which these conclusions are based were obtained from the Graefenberg seismograph array, which is located in West Gemany and consists of 13 stations separated by distances of 10 km to 100 km. We propose that relative arrival times of PKP from Tonga could be used in the Mediterranean - Middle East area to search for precursory travel time changes before large earthquakes.     

建设数字地震 促进防震减灾

本文提出了“数字地震”的概念 ,讨论它的主要内容和问题 ,并对建设“数字地震”提出若干建设性意见。     

Evaluation of seismic ground motion induced by topographic irregularity

Results of an extensive numerical study on the 2D scattering of seismic waves by local topography are presented. The investigation has been conducted using the direct boundary element method. Several types of topography (slopes, canyons and ridges) are considered. The influences of some key parameters, such as exciting frequency and geometry of the irregular feature, on surface ground motion are studied in detail. It is found that local topographic conditions play an important role in the modification of seismic ground motion at the irregular feature itself and its neighbourhood. The present results can be considered to be useful from the viewpoint of earthquake engineering and seismology.     

Influence of the Kunlun Mountain Ms8.1 Earthquake on Horizontal Crustal Deformation in the Sichuan and Yunnan Area

In order to track the space-time variation of regional strain field holistically(in a large scale) and to describe the regional movement field more objectively,the paper uses a nonlinear continuous strain model focused on extracting medium-low frequency strain information on the basis of a region with no rotation.According to the repeated measurements(1999～2001～2004) from GPS monitoring stations in the Sichuan and Yunnan area obtained by the Project of "China Crust Movement Measuring Network",and with the movement of 1999～2001(stage deformation background) as the basic reference,we separated the main influencing factors of the Kunlun Mountain M-S8.1 earthquake in 2001 from the data of 2001 and 2004,and the results indicate:(1) the Kunlun Mountain M-S8.1 earthquake has a discriminating effect on the Sichuan and Yunnan area,moreover,the deformation mode and background had not only certain similitude but also some diversity;(2) The movement field before the earthquake was very ordinal,while after the earthquake,order and disorder existed simultaneously in the displacement field;The displacement quantities of GPS monitoring stations were generally several millimeters;(3) The principal strain field before earthquake was basically tensile in an approximate EW direction and compressive in the SN direction,and tension was predominant.After the earthquake,the principal strain field in the Sichuan area was compressive in the EW direction and tensile in the SN direction,and the compression was predominant.In the Yunnan area,it was tensional in the NE direction and compressive in the NW direction,and tension was predominant;(4) The surficial strain before the earthquake was dominated by superficial expansion,the contractive area being located basically in the east boundary of Sichuan and Yunnan block and its neighborhood.After the earthquake,the Sichuan area was surface contractive(the further north,the greater it was),and south of it was an area of superficial expansion.Generally speaking,the Kunlun Mountain M-S8.1 earthquake played an active role in the accumulation of energy in the Sichuan and Yunnan area.Special attention shall be focused on the segment of Xichang-Dongchuan and its neighborhood.     

2006年甘肃文县5.0级地震灾害损失评估

2006年6月21日在甘肃省文县发生MS5.0地震,造成了建筑物破坏及人员伤亡。在震后开展的地震现场考察与震害评估工作中,将灾区分为2个评估子区,完成了29个点的震害抽样调查工作,根据地震灾害损失评估系统EDLES2.5的要求建立了有关数据库,做出了经济损失评估,并针对灾害特点给出了灾区恢复重建的建议。     

统计预测、经验预测、物理预测——近期国际地震预测预报研究的启示

从"统计预测"、"经验预测"、"物理预测"的角度讨论了世纪之交地震预测预报研究的国际进展。"统计预测"包括地震预测预报方法的统计检验、"统计地震学",以及统计物理在地震预测预报中的应用;"经验预测"包括搜索可能的前兆异常的尝试、建立将可能的前兆异常现象与地震孕育过程联系起来的简单模型、发现对地震预测预报研究具有重要意义的新现象,以及地球介质变化的动态监测试验;"物理预测"包括地震孕育和发生的物理模型、地震断层带性质的观测和实验研究,以及对震源的直接探测和钻探。讨论了"统计预测"、"经验预测"、"物理预测"之间的关系,对"把经验预测或统计预测变成物理预测"的发展战略提出质疑。