清水李沟井与礼县石桥井流量异常变化与地震的关系

分析了清水李沟井与礼县石桥井汉量变化与邻近地区发生的中强地震的对应关系。发现在邻近地区发生的部分中强地震前半年左右2口井的流量开始出现上升或波动现象，异常变化的幅度最大可达3．75mL/s，对震级较小，而且距离较远的地震无明显的异常反映。2口井流量异常对5级地震的映震范围为250km，6级地震为350km，7级地震为500km。     

Casualties‘ States During Destructive Earthquakes

The index of casualties is introduced for the trapped that is still alive after a destructive earthquake to indicate his(her)injury degree.In order to describe the injury-developing process controlled by three factors:the initial injury degree,the trap surroundings and the physique of the cornered,a function SFC( State-Function of Casualties) can be naturally constructes.Through parameter analysis from eight pieces of figures,it can be found that the trapped with weaker physique and worse initial injury degree and in adverse trap surroundings deserves sooner rescue.     

Analysis on Depth Distribution and Precursor Mechanism of Small and Moderate Earthquakes

ＩＮＴＲＯＤＵＣＴＩＯＮＲｅｓｅａｒｃｈｏｎｅａｒｔｈｑｕａｋｅｆｏｃｕｓｄｅｐｔｈｄｉｓｔｒｉｂｕｔｉｏｎａｎｄｉｔｓｐｈｙｓｉｃａｌｂａｃｋｇｒｏｕｎｄｉｓｏｎｅｏｆｍｏｓｔａｔ ｔｅｎｔｉｖｅｐｒｏｂｌｅｍｓ.Ｐｒｏｆ.ＦｕＺｈｅｎｇｘｉａｎｇ (1 996)ｒｅｓｅａｒｃｈｅｄｔｈｅｒｅｌａｔｉｏｎｓｂｅｔｗｅｅｎｆｏｃｕｓｄｅｐｔｈｄｉｓｔｒｉｂｕ ｔｉｏｎｏｆａｆｔｅｒｓｈｏｃｋｓ ,ｃｒｕｓｔａｌｖｅｌｏｃｉｔｙｌａｙｅｒｓａｎｄｓｕｒｆａｃｅｔｈｅｒｍａｌｆｌｏｗ .Ｒｅｓｅａｒｃｈｏｎｆｏｃｕ…     

Post-earthquake investigation on several geosynthetic-reinforced soil retaining walls and slopes during the Ji-Ji earthquake of Taiwan

This paper gives an overview on the application of geosynthetic-reinforced soil structures in Taiwan. Taiwan has an unique topography and geotechnical conditions that rendered a less conservative and more challenging design compared to that of North America, Europe and Japan. The Ji-Ji (Chi-Chi) earthquake of 1999 gave an opportunity to examine the behavior of reinforced soil structures. The performance of several modular-block reinforced soil retaining walls and reinforced slopes at the vicinity of the fault was evaluated. Reinforced structures performed better than unreinforced soil retaining walls. The failure cases were highlighted and the cause of failure was identified. The lack of seismic design consideration could be a major cause of failure. The compound failure mode, the inertia force of the blocks, and the connection stiffness and strength relative to the large dynamic earth pressure, were among major items that would warrant further design consideration.     

Effectiveness of structural control based on control energy perspectives

A computational algorithm for maximizing the control efficiency in actively controlling the elastic structural responses during earthquake is proposed. Study of optimal linear control using a single degree of freedom shows that applying active control is very effective in reducing the structural displacement and velocity responses for long‐period structures, but at the same time it has an adverse effect in increasing the absolute acceleration response. The extent of this adverse effect reduces the effectiveness of the control system, and therefore it poses a limit on the maximum control force in order to provide maximum control efficiency. In view of this shortcoming, maximum control energy dissipation is used to define the most effective optimal linear control law. Less displacement and velocity response are expected as larger control force is applied, but there is always a limit that maximum control energy can be dissipated. This study shows that this limit depends on the structural characteristics as well as the input ground motion, and a general trend is that the maximum control energy decreases as damping increases. Finally, application of the proposed algorithm on a six‐storey hospital building is presented to show the effectiveness of using optimal linear control on a multi‐degree‐of‐freedom system from the control energy perspectives. Copyright © 2001 John Wiley & Sons, Ltd.     

Probabilistic Seismic Hazard Assessment Along the Southeastern Coast of Vietnam

On the basis of the analysis of geological, tectonic characteristics and earthquake manifestation features, a causative relation between geodynamic regime and seismicity has been established for the southeastern coastal zone and continental shelf of Vietnam. The probabilistic methods have been used to evaluate ground shaking effects at Nha Trang city aswell as for the entire study area. Short, intermediate and long term predictions of ground shaking (in the form of peak ground accelerationmaps) show high risks in the coastal zone of central Vietnam and in the southeastern continental shelf of the country.     

北部湾地震的动力学参数与应力场

从震源机制和动力学参数方面讨论了北部湾地震的震源应力场，结果表明，主震是在北东东向构造的作用下发生的，同时计算了动力学参数如破裂长度，地震矩，应力降，破裂面积和平均位错等，并探讨了非线性地震与较大余震的关系。     

近海地震活动特征及其测震学前兆的某些研究

利用反映震级－频度关系的参量Ｃ值，η值，ｂ值和ｂ值谱以及反映地震空间分布的森下指等研究了近海地震活动的一些主要特征，发现近海强震前地震活动性指标及图象的变化特征与陆地上强震前的特征存在一定差异；给出了新研究的可用于近海及滨海地区强震预报的短期和临震     

地震断层气监测的现状与展望

断层气测量是地震科学研究的重要方法之一，断层气测量具有实用、轻便、快便、价廉等优点，在地震监测预报和减灾活动中具有广阔的应用前景和巨大的潜力。本文对断层气测量在地震科学中的应用和现状作了简要的介绍，同时探讨了我国地震断层气监测系统中存在的一些主要问题，对今后的发展进行了展望。最后简单介绍了几种断层气监测新技术及新型气敏传感器。     

鲜水河断裂带北西段的枢纽运动与强震的发生

由炉霍，道孕，乾宁三条次级断裂左阶斜列组合而成的鲜水河断裂带的北西段。在断裂左旋走滑运动中，普遍出现断裂的枢纽运动。在产生的枢纽轴部，是强震发生的最佳地质的构造部位。近代发生的１９７３年炉霍７．６级地震，１０２３年炉堆道孕间介促７．３级地震，１８９３年乾宁７．３级地震，都分别发生在断裂的枢纽轴部，审由于枢纽部易于造成闭锁的结果。