Investigating Landslides Caused by Earthquakes – A Historical Review

Post-earthquake field investigations of landslide occurrence have provided a basis for understanding, evaluating, and mapping the hazard and risk associated withearthquake-induced landslides. This paper traces thehistorical development of knowledge derived from these investigations. Before 1783, historical accounts of the occurrence of landslides in earthquakes are typically so incomplete and vague that conclusions based on these accounts are of limited usefulness. For example, the number of landslides triggered by a given event is almost always greatly underestimated. The first formal, scientific post-earthquake investigation that included systematic documentation of the landslides was undertaken in the Calabria region of Italy after the 1783 earthquake swarm. From then until the mid-twentieth century, the best information on earthquake-induced landslides came from a succession ofpost-earthquake investigations largely carried out by formal commissions that undertook extensive ground-based field studies. Beginning in the mid-twentieth century, when the use of aerial photography became widespread, comprehensive inventories of landslide occurrence have been made for several earthquakes in the United States, Peru, Guatemala, Italy, El Salvador, Japan, and Taiwan. Techniques have also been developed for performing ``retrospective' analyses years or decades after an earthquake that attempt to reconstruct the distribution of landslides triggered by the event. The additional use of Geographic Information System (GIS) processing and digital mapping since about 1989 has greatly facilitated the level of analysis that can applied to mapped distributions of landslides. Beginning in 1984, syntheses of worldwide and national data on earthquake-induced landslides have defined their general characteristics and relations between their occurrence and various geologic and seismic parameters. However, the number of comprehensive post-earthquake studies of landslides is still relatively small, and one of the most pressing needs in this area of research is for the complete documentation of landslides triggered by many more earthquakes in a wider variety of environments.     

泾阳4.8级地震的构造背景

1998年1月5日烃阳Ms 4.8地震是陕西省近40年来发生的最大一次地震。研究了此次地震的构构背景和地球物理场特征。     

金风口地面塌陷及水源干枯成因及防治

通过对金风口片区地表的调查，分析了地面降沉、塌陷的原因；研究了塌陷对水源的影响；总结了水源干枯的规律及影响因素；并提出了防治的办法及合理化建议。     

山东省集雨增补地下水与水资源可持续利用探讨

分析了山东省水资源特点、开发利用状况以及水资源持续利用所面临的形势，在阐述山东省降雨、地理等自然特点的基础上，认为集雨增补地下水是实现水资源可持续利用的有效途径，提出了集雨增补地下水的技术措施。     

南京市玄武湖水下交通隧道环境地质评价

玄武湖地下交通隧道既在城市,又在水下,环境地质条件极为复杂,是一种脆弱环境下的典型的地质工程。本文对玄武湖地下交通隧道的环境地质条件特别是水文地质条件进行了评价,预测了可能出现的如水污染、地面沉降、地面塌陷、巷道突水等环境地质问题,并提出了相应的防治对策。     

探地雷达检测道路厚度结构的应用现状及进展

对探地雷达检测道路厚度结构的应用现状进行介绍,分析雷达检测道路厚度结构的物理前提.将探地雷达的道路厚度检测技术与常规的钻孔取芯方法进行对比,并根据笔者在工作中应用的实际情况,说明探地雷达在公路厚度结构检测方面有广阔应用前景.     

现代抗震设计理论的发展过程

介绍了现代抗震设计理论的发展过程，基于性态的抗震设计理论的提出背景、发展情况及研究内容；详细介绍了基于性态的抗震设计理论的抗震设防方法；指出了基于性态的抗震设计理论与传统抗震设计理论的主要区别及特点。     

医院住院部大楼抗震性能评价

以某医院住院部大楼为例进行结构抗震性能评价，首先分析了场址的地震环境，开展了地震危险性分析工作，合成了不同地震危险水平下的地震动加速度时程。进而，通过对结构的模型简化，应用时程分析方法分析结构的抗震性能，得出了一些对其改造加固有意义的结论。     

最不利地震动在网壳结构抗震设计中的应用

利用文献提供的最不利地震动，对网壳结构等大跨空间结构进行了分析，分别考察了仅水平输入和三向地震波输入的两种情况，对最不利地震动在网壳结构抗震设计中的适用性进行了探讨，并在一实际工程设计中进行了应用。大跨度空间结构在水平地震动输入时，宜按照的最不利地震动进行设计；在三向地震动同时输入时，应同时分别按所推荐最不利设计地震动和按常规选用的地震动，对大跨度空间结构进行抗震分析。     

Optimum multiple tuned mass dampers for structures under the ground acceleration based on the uniform distribution of system parameters

The five MTMD models, with natural frequencies being uniformly distributed around their mean frequency, have been recently presented by the first author. They are shown to have the near‐zero optimum average damping ratio (more precisely, for a given mass ratio there is an upper limit on the total number, beyond which the near‐zero optimum average damping ratio occurs). In this paper, the eight new MTMD models (i.e. the UM‐MTMD1～UM‐MTMD3, US‐MTMD1～US‐MTMD3, UD‐MTMD1 and UD‐MTMD2), with the system parameters (mass, stiffness and damping coefficient) being, respectively, uniformly distributed around their average values, have been, for the first time here, proposed to seek for the MTMD models without the near‐zero optimum average damping ratio. The structure is represented by the mode‐generalized system corresponding to the specific vibration mode that needs to be controlled. Through minimization of the minimum values of the maximum dynamic magnification factors (DMF) of the structure with the eight MTMD models (i.e. through the implementation of Min.Min.Max.DMF), the optimum parameters and values of Min.Min.Max.DMF for these eight MTMD models are investigated to evaluate and compare their control performance. The optimum parameters include the optimum mass spacing, stiffness spacing, damping coefficient spacing, frequency spacing, average damping ratio and tuning frequency ratio. The six MTMD models without the near‐zero optimum average damping ratio (i.e. the UM‐MTMD1～UM‐MTMD3, US‐MTMD1, US‐MTMD2 and UD‐MTMD2) are found through extensive numerical analyses. Likewise, the optimum UM‐MTMD3 offers the higher effectiveness and robustness and requires the smaller damping with respect to the rest of the MTMD models in reducing the responses of structures subjected to earthquakes. Additionally, it is interesting to note, by comparing the optimum UM‐MTMD3 with the optimum MTMD‐1 recently investigated by the first author, that the effectiveness and robustness for the optimum UM‐MTMD3 is almost identical to that for the optimum MTMD‐1 (without inclusion of the optimum MTMD‐1 with the near‐zero optimum average damping ratio). Recognizing these performance benefits, it is preferable to employ the optimum UM‐MTMD3 or the optimum MTMD‐1 without the near‐zero optimum average damping ratio, when installing the MTMD for the suppression of undesirable oscillations of structures under earthquakes. Copyright © 2003 John Wiley & Sons, Ltd.