Suspended sediment and total dissolved solid yield patterns at the headwaters of Urumqi River,northwestern China: a comparison between glacial and non‐glacial catchments

In order to understand the differences in the suspended sediment and total dissolved solid (TDS) yield patterns between the glacial and non‐glacial catchments at the headwaters of Urumqi River, northwestern China, water samples were collected from a glacier catchment and an empty cirque catchment within the region, during three melting seasons from 2006 to 2008. These samples were analyzed to estimate suspended sediment and TDS concentrations, fluxes and erosion rates in the two adjoining catchments. There were remarked differences in suspended sediment and TDS yield patterns between the two catchments. Suspended sediment concentrations were controlled mainly by the sediment source, whereas TDS concentrations were primarily related to the hydrologic interaction with soil minerals. Generally, the glacial catchment had much higher suspended sediment and TDS yields, together with higher denudation rates, than the non‐glacial catchment. Overall, glacial catchment was mainly dominated by physical denudation process, whereas the non‐glacial catchment was jointly influenced by physical and chemical denudation processes. The observed differences in material delivery patterns were mainly controlled by the runoff source and the glacial processes. The melting periods of glacier and snow were typically the most important time for the suspended sediment and TDS yields. Meanwhile, episodic precipitation events could generate disproportionately large yields. Subglacial hydrology dynamics, glaciers pluck and grind processes could affect erodibility, and the large quantities of dust stored on the glacier surface provided additional sources for suspended sediment transport in the glacial catchment. These mechanisms imply that, in response to climate change, the catchment behaviour will be modified significantly in this region, in terms of material flux. Copyright © 2013 John Wiley & Sons, Ltd.     

地震科普视频点播系统的设计与实现

地震的科普知识是公众关心的内容,为了更好地向公众普及地震科普知识,利用流媒体技术设计了基于流媒体技术的地震科普视频点播系统。主要介绍了地震科普视频点播系统的系统设计、系统实现的关键技术以及在地震行业中的应用。     

《地震工程与工程振动》的办刊理念及质量控制

总结《地震工程与工程振动》32年来的办刊经验,分析期刊服务范畴,围绕期刊办刊理念定位。阐述了提高期刊质量的具体方法,要掌握学科前沿的发展,提高论文的时效性,保证文章创新,把好学术质量关,对科研特色人才群体进行追踪,积极组织约稿等,为学术交流搭建快捷、高效的平台。     

2014年2月12日新疆于田7．3级地震抗震安居（安居富民）房破坏比初步分析

2014年2月12日新疆于田Ms7．3地震是新疆开展抗震安居（安居富民）房建设以来首次产生较大规模成灾破坏震例,以震区抗震房不同结构类型破坏程度和抽样调查数据确定震区抗震房Ⅵ度区和Ⅶ度区的破坏比,与新疆历史破坏性地震相似结构类型房屋的破坏比进行对比分析。     

2008年汶川MS8.0地震反应谱平台值衰减特性研究

2008年汶川M_S8.0地震获得了大量的强震动记录, 为研究反应谱特征参数衰减特性提供了重要的基础资料. 本文对已知场地条件的174个台站的记录进行研究, 计算其加速度反应谱并按照最小二乘分段拟合方法进行标定, 进而拟合了反应谱平台值的衰减关系;对比分析了水平方向与竖直方向反应谱平台值的衰减特性, 提出用“平台值的场地衰减影响系数”来定量研究不同场地类型对反应谱平台值的影响, 用“衰减曲线下降速率”来定量分析不同衰减曲线的衰减速率. 通过计算得出水平向Ⅰ, Ⅱ, Ⅲ类场地的平台值场地衰减影响系数平均值分别为0.5358, 1和1.579, 且Ⅲ类场地的加速度平台值衰减曲线的衰减速率最小.      

北京中关村地区公众防震减灾意识社会调查及分析

通过对北京中关村地区人群的问卷调查及其分析,了解到受访人群对待防震减灾的工作和措施的态度是积极的,大部分人已经基本具备一定的防震减灾意识和正确逃生和减轻地震灾害的常识。但是,多数人还不了解地震预报现状和地震预报发布程序,地震谣言还具有相当的生存空间和流传基础,基本医疗救护知识还不十分普及。同时,调查结果也显示了不同媒体和宣传渠道对公众的影响力。调查分析结果对今后开展防震减灾宣传教育工作具有重要的参考意义。     

Study on inelastic displacement ratio spectra for near-fault pulse-type ground motions

In displacement-based seismic design, inelastic displacement ratio spectra (IDRS) are particularly useful for estimating the maximum lateral inelastic displacement demand of a nonlinear SDOF system from the maximum elastic displacement demand of its counterpart linear elastic SDOF system. In this study, the characteristics of IDRS for near-fault pulse-type ground motions are investigated based on a great number of earthquake ground motions. The in? uence of site conditions, ratio of peak ground velocity (PGV) to peak ground acceleration (PGA), the PGV, and the maximum incremental velocity (MIV) on IDRS are also evaluated. The results indicate that the effect of near-fault ground motions on IDRS are signifi cant only at periods between 0.2 s - 1.5 s, where the amplifi cation can approach 20%. The PGV/PGA ratio has the most signifi cant in? uence on IDRS among the parameters considered. It is also found that site conditions only slightly affect the IDRS.     

Torsional vibrations of elastic foundation on saturated media

A comprehensive analytical solution is developed to examine the torsional vibration of an elastic foundation on a semi-infinite saturated elastic medium for the first time. First, the governing equations of saturated media are solved by use of Hankel transform techniques. Then, based on the assumption that the contact between the foundation and the half-space is perfectly bonded, this dynamic mixed boundary-value problem can lead to dual integral equations, which are further reduced to the standard Fredholm integral equations of the second kind and solved by numerical procedures. Numerical examples are given at the end of the paper. The numerical results indicate that the response of the elastic foundation strongly depends on the material and geometrical properties of both the saturated soil-foundation system and the load acting on the foundation. In most of the cases, the dynamic behavior of an elastic foundation on saturated media significantly differs from that of a rigid plate bearing on the elastic half-space.     

Evaluation of pile foundation response to lateral spreading

The effects of liquefaction on deep foundations are very damaging and costly, and they keep recurring in many earthquakes. The first part of the paper reviews the field experience of deep foundations affected by liquefaction during earthquakes in the last few decades, as well as the main lessons learned. The second part of the paper presents results of physical modeling of deep foundations in the presence of liquefaction conducted by the authors and others at the 100g-ton RPI centrifuge. In the last decade centrifuge modeling has been identified as a key tool to identify and quantify mechanisms, calibrate analyses and evaluate retrofitting strategies for pile foundations. Results are presented of centrifuge models of instrumented pile foundations subjected to lateral spreading, including single pile and pile groups, 2- and 3-layer soil profiles, mass and stiffening elements above ground to incorporate the effect of the superstructure, and evaluation of proposed retrofitting strategies. Interpretations of these centrifuge experiments and their relation to field observations and soil properties.