2013年3月11日阿图什5．2级地震灾害损失评估和房屋震害特征分析

2013年3月11日新疆阿图什发生慨5．2地震,震中烈度Ⅵ度,地震没有造成人员伤亡,个别民宅倒塌,造成直接经济损失2397万元。结合此次地震考察评估工作,分析此次地震造成经济损失的震害原因。从房屋破坏、房屋建筑场地条件和抗震安居工程三点,描述了此次地震的震害特征,与新疆伽师、莎车等具有相同地质条件的地区进行震后对比,并结合2009年4月22日发生的新疆阿图什Ms5．0地震,提出了对此次地震的认识与建议。     

澳大利亚地震危险性和灾害风险评估中的场地分类

尽管场地响应现象已是全球都公认的,然而对澳大利亚的许多地区,之前并没有研究过风化层属性对地震动的影响。为了描述风化层能改变地震动的特性,本文通过验证研究评估了为一级地震危害性和灾害风险评估的应用而编制的澳大利亚全国场地分类图。在缺乏风化层厚度和基本周期数据的情况下,场地类别根据在加利福尼亚研制的利用地质材料与地层上部30m的剪切波速度（VS30）的关系的方法进行归类。随后将这一分类方案调整到适合澳大利亚的地质环境,包括对这一稳定地质构造中通常碰到的原地风化表层土存在的校正。本文所得结果用纽卡斯尔、悉尼和珀斯市区各种第四纪沉积环境和横跨澳大利亚各种场地基岩优势环境的地球物理数据和岩土数据进行了验证。这些分析的结果说明了在地震危险性评估的场地类别中应用限定深度的剪切波速度方法的有效性,但同时也突出了局限性。     

2011年5月11日西班牙东南洛尔卡Mw5．1地震诱发的大范围滑坡

2011年5月11日,一个中等震级地震（Mw5．1）袭击了西班牙东南部洛尔卡城和邻近地区,造成了显著的破坏和人员伤亡。通过地震影响区的野外考察对250多处主要是碎裂型（岩／土崩塌、碎裂的土质滑坡和岩崩）诱发滑坡进行了定点和特征描述。与以前该区域相似震级（Mw4．7～5．0）的地震事件,以及以前预测地震期间斜坡表现的模型结果相比,本次地震诱发滑坡的数量相当大。提出了几个原因来解释这种差异：（1）地震序列中相对高震级（Mw4．5）的前震可能弱化了区域内的斜坡强度;（2）这些事件产生了高的地震动峰值;（3）发生了地形场地效应。本研究的结果指出了在改进区域斜坡特征研究模型时考虑这些影响的重要性。     

新疆及哈萨克斯坦地下流体氦气震兆特征

分析新疆10泉、04泉及哈萨克斯坦卡帕尔—阿拉善4井、下卡姆卡井氦气(He)含量变化的源兆、场兆、远兆的映震特征,地震前兆异常表现为:上升(或下降)幅度、速率变化超出正常范围,具有较好的重复性,测值遵循背景值—趋势性上升(或突升)—恢复至背景值;趋势性下降(或突降)—恢复至背景值的变化过程.各监测点氦气异常形态、异常持续时间、异常幅度同源兆、场兆、大震远兆没有明显的关系;由于各观测点的水文地质条件和地球化学环境不同,不同监测点氦气映震能力有较大差异,其中新10号泉和卡帕尔—阿拉善4井氦气的映震能力较强.     

Soil bentonite wall protects foundation from thrust faulting: analyses and experiment

When seismic thrust faults emerge on the ground surface,they are particularly damaging to buildings,bridges and lifelines that lie on the rupture path.To protect a structure founded on a rigid raft,a thick diaphragm-type soil bentonite wall(SBW) is installed in front of and near the foundation,at sufficient depth to intercept the propagating fault rupture.Extensive numerical analyses,verified against reduced–scale(1 g) split box physical model tests,reveal that such a wall,thanks to its high deformability and low shear resistance,"absorbs" the compressive thrust of the fault and forces the rupture to deviate upwards along its length.As a consequence,the foundation is left essentially intact.The effectiveness of SBW is demonstrated to depend on the exact location of the emerging fault and the magnitude of the fault offset.When the latter is large,the unprotected foundation experiences intolerable rigid-body rotation even if the foundation structural distress is not substantial.     

Dominant pulse simulation of near fault ground motions

In this study, a new mathematical model is developed composed of two parts, including harmonic and polynomial expressions for simulating the dominant velocity pulse of near fault ground motions. Based on a proposed velocity function, the corresponding expressions for the ground acceleration and displacement time histories are also derived. The proposed model is then fitted using some selected pulse-like near fault ground motions in the Next Generation Attenuation (NGA) project library. The new model is not only simple in form but also simulates the long-period portion of actual velocity near fault records with a high level of precision. It is shown that the proposed model-based elastic response spectra are compatible with the near fault records in the neighborhood of the prevailing frequency of the pulse. The results indicate that the proposed model adequately simulates the components of the time histories. Finally, the energy of the proposed pulse was compared with the energy of the actual record to confirm the compatibility.     

Ice- and cryogel-soil composites in water-retaining elements in embankment dams constructed in cold regions

There are a number of serious problems connected with building and repairing water-retaining elements in embankment dams in cold regions. One of them is the difficulty in finding inexpensive clay materials with the necessary structural properties and using them in the winter. Another is the cracks that appear in the upper part of a dam when the core freezes to the banks, and leakage along the cracks threatens to destroy the dam. Still another is the process of erosion at the bottom of the core which may occur through fissures in the rock foundation of a dam and in transport constructions. Also, the behaviour of water-retaining elements during earthquakes is unreliable. All of these problems can be solved by using ice- and cryogel-soil composites created by cryotropic gel formation (CGF). Our laboratory investigations demonstrate that the materials proposed for water-retaining elements have the necessary permeable, plastic, thermophysical, and strength properties to solve all of these problems. Certain constructions of water-retaining elements which may prove to be both safe and cost-effective are proposed. However, these ice- and cryogel-soil composites need to be field-validated before they are used in dams and transport structures in cold regions.     

北吕宋岛菲律宾活动带蛇绿岩及其上覆浊积岩的放射虫研究新进展

The basement of the Philippine Mobile Belt (PMB) is mainly composed of ophiolites that are mostly overlain by Paleogene to Miocene turbidites in central Luzon. To clarify the geological development of the PMB with respect to the initial stage of the arc volcanism (eg. Yumul et al., 2003, 2008; Dimalanta and Yumul, 2003; Suzuki et al., 2011), radiolarian dating was examined in siliceous sediments associated with the ophiolites and turbidites. The samples were collected from sites identified with the Zambales and Montalban ophiolites, basic tuff phyllites in NW Din-galan, and their overlying formations.