西秦岭北缘断裂带地震危险段的研究

通过对西秦岭北缘断裂带全新世活动,地震活动和现今排气活动等特征的分析研究,认为本断裂带东段是地震危险段,未来发生强震（Ｍｓ≥６）的机率最大。     

Potential of marble dust to stabilise red tropical soils for road construction

The potential of marble dust as a stabilizing additive to red tropical soils was evaluated. The evaluation involved the determination of the geotechnical properties of three different red tropical soils in their natural state as well as when mixed with varying proportions of marble dust. The parameters tested included the particle size distribution, specific gravity, Atterberg limits, the standard compaction characteristics, the compressive strength and the California bearing ratio (CBR). The strength tests were repeated after normal 28 day curing of the treated samples and also after accelerated 24 h curing at temperatures of 40°C, 60°C and 80°C.

Results showed that the geotechnical parameters of red tropical soils are improved substantially by the addition of marble dust; plasticity was reduced by 20 to 33% and strength and CBR increased by 30 to 46% and 27 to 55% respectively. The highest strength and CBR values were achieved at 8% marble dust. Results also showed that normal 28 day curing improved the strength of the marble dust-treated soil with over 80% strength gain achieved after 7 to 10 days of normal curing. Higher strength development was realised following accelerated 24 h curing at 60°C.

Although these results imply marked improvement in the geotechnical parameters of red tropical soils, the higher strength developed is not enough for the improved soil to be used as a base material in the construction of heavily trafficked flexible pavements. The improved material may, however, be successfully used as base material for lightly trafficked roads and as a sub-base material for heavily trafficked roads.     

Urban steeplands in the tropics: an environment of accelerated erosion

The developing countries at present have a high urban growth rate that is likely to continue for at least another quarter-century. In addition, many of these urban centres are located in the Neogene plate boundary zones and are subject to multiple earthquake and volcanic hazards. Slope failures and accelerated surface and channel erosion are particularly severe in cities near active plate margins, and in areas affected also by tropical cyclones. We discuss two extreme cases: Singapore and Kingston (Jamaica). Singapore is located in a stable environment and the urbanization related problems of flood and slope instability have been reduced by proper building and drainage practices at a considerable cost. In Kingston, the external disturbances are repetitive, large-scale, and very difficult to control. The fast-growing cities in the tropics need to be carefully monitored, especially when located in an unstable physical environment. This revised version was published online in July 2006 with corrections to the Cover Date.     

山东临沂西部地区次火山杂岩与金矿成矿系列

临沂西部地区潜火山杂岩体广泛发育,其分布及产出主要受两组断裂构造控制,潜火山杂岩体岩石类型复杂,主要有：闪长玢岩系列,花岗闪长岩系列,正长岩系列,二长斑岩系列。据潜火山杂岩体与金矿成矿的密切时空关系,建立了区内金矿床成矿系列：闪长玢岩铜、铁、金成矿系列;花岗闪长岩金、铜、铁成矿系列;正长岩金、钼、铅成矿系列;二长斑岩金、银、碲成矿系列。     

伽玛能谱参数与金矿找矿

γ能谱测量方法是一种简便、有效、快速的间接找金的方法,不同类型的金矿其伽玛能谱特征并不相同。与深成脉岩活动有关的脉状金矿,具有明显的伽玛能谱Ｋ／Ｕ参数异常;与中浅成中酸性侵入发杂岩体有关的金矿,具有Ｋ／Ｕ,Ｋ／Ｔｈ参数正异常;而与浅成－超玫成偏碱性杂岩体有关的隐爆角砾岩型金矿,则具有一致的Ｕ,Ｔｈ,Ｋ及Ｆ参数正异常。本介绍了在山东东部乳山地区及临沂西部地区,利用没的伽玛能谱参数进行不同类型的金矿     

地震期间的地磁脉动效应

１９９６年１１月１７日至１１月２９日在新疆喀仁地区８次地震期间观测到的震前发生的高频地磁脉动现象,文中对每次地震前的Ｐｃｌ－２脉动的形态,以及脉动的起动时刻,持续时间,Ｈ分量和Ｄ分量的平均振幅随北京地方时的分布进行了详细研究分析,对这种震前观测到的高频地磁脉动的激发机制也做了深入的讨论,事实表明,这种震前发生的高频地磁脉动的地震的短期预报上可能有广泛的应用前景。     

Seismicity acceleration model and its application to several earthquake regions in China

With the theory of subcritical crack growth, we can deduce the fundamental equation of regional seismicity acceleration model. Applying this model to intraplate earthquake regions, we select three earthquake subplates: North China Subplate, Chuan-Dian Block and Xinjiang Subplate, and divide the three subplates into seven researched regions by the difference of seismicity and tectonic conditions. With the modified equation given by Sornette and Sammis (1995), we analysis the seismicity of each region. To those strong earthquakes already occurred in these region, the model can give close fitting of magnitude and occurrence time, and the result in this article indicates that the seismicity acceleration model can also be used for describing the seismicity of intraplate. In the article, we give the magnitude and occurrence time of possible strong earthquakes in Shanxi, Ordos, Bole-Tuokexun, Ayinke-Wuqia earthquake regions. In the same subplate or block, the earthquake periods for each earthquake region are similar in time interval. The constant αin model can be used to describe the intensity of regional seismicity, and for the Chinese Mainland, α is 0.4 generally. To the seismicity in Taiwan and other regions with complex tectonic conditions, the model does not fit well at present.     

CT诊断胸部平片隐匿部位肿瘤的检出价值

本文对２２７例胸部肿瘤中的３４例Ｘ线不易发现的肿瘤进行了Ｘ线与ＣＴ诊断的对照分析,此组病例共占胸部肿瘤的１４．９％,胸部隐匿部位的肿瘤在传统Ｘ光正位胸片上受组织重叠的影响是不易看到的,容易漏诊,须通过ＣＴ扫描检查方可观察到,ＣＴ扫描是诊断胸部隐匿部位肿瘤的最好,最有效的检查方法之一。     

中国及邻区岩石层密度三维结构

利用中国及邻区２×２Ｓ波速地震三维层析成像和３０’×３０’重力资料．首先采用密度差与Ｓ波速差的经验关系式,建立起中国及邻区的岩石层密度初始模型,再利用布格重力异常进行阻尼最小二乘法反演,得到该区岩石层三维密度分布结果．反演结果表明：１．中国地区密度异常分布与大地构造分区有着明显的相关性,高密度区对应古老地块,低密度区对应高原及山区,在不同块体边界存在着密度异常梯级带;２．岩石层地幔密度分布与地壳密度分布特征不一致．