Land uplift near Vatnajökull, Iceland, as observed by GPS in 1992, 1996 and 1999     

Lars E. Sjöberg  Ming Pan  Sigurdur Erlingsson  Erick Asenjo  Kolbeinn Arnason 《Geophysical Journal International》2004,159(3):943-948

  相似文献   

竖向地震动强度包络函数的空间变化规律          下载免费PDF全文

钟菊芳  胡晓  屈铁军  吴胜兴 《地震工程学报》2005,27(1):42-46

利用SMART 1台阵三次地震记录拟合了各个测点在地震中的竖向地震动强度包络曲线及Amin 和Ang的强度包络函数中各模型参数值,分析了各模型参数的空间变化规律,建立了各模型参数随二维空间坐标及土层厚度变化的随机模型,为多点地震动合成中竖向强度包络函数的计算提供了理论依据。  相似文献   

锦州地震台体积式钻孔应变仪的映震情况     

明成山  李京锦  李哲 《地震地磁观测与研究》2005,(Z1)

论述了张北MS6.2、沈阳ML4.1、内蒙古ML5.9、日本北海道MS8.0、俄蒙中交界MS7.9、青海昆仑山MS8.1地震前后,锦州地震台体积式钻孔应变仪观测震前异常的变化规律。通过计算潮汐因子、振幅因子、3点线性平滑滤波残差值等方法,识别异常。结果表明,体应变异常资料与地震有一定的相关性。  相似文献   

A precise monitoring of snow surface height in the region of Lambert Glacier basin-Amery Ice Shelf,East Antarctica   总被引：2，自引：0，他引：2  

I.Allison 《中国科学D辑(英文版)》2005,48(1):100-111

The net surface snow accumulation on the Antarctic ice sheet is determined by a combination of precipitation, sublimation and wind redistribution. We present a one-year record of hourly snow-height measurements at LGB69 (70°50'S, 77°04'E, 1850 m a.s.l.). east side of Lambert Glacier basin (LGB), and 4 year record at G3 (70°53'S, 69°52'E, 84 m a.s.l.), Amery Ice Shelf (AIS). The measurements were made with ultrasonic sensors mounted on automatic weather stations installed at two sites. The snow accumulation at LGB69 is approximately 70 cm. Throughout the winter, between April and September, there was little change in surface snow height (SSH) at the two sites. The negative SSH change is due to densification at LGB69, and is due to both ablation and densification at G3. The strongest accumulation at two sites occurred during the period between October and March (accounting for 101.6% at LGB69), with four episodic increasing events occurring during 2002 for LGB69, and eight events during 1999-2002 for G  相似文献   

Delayed geochemical hazard: Concept, digital model and case study     

CHEN Ming  FENG Liu  Jacques Yvon 《中国科学D辑(英文版)》2005,48(Z2)

Delayed Geochemical Hazard (DGH briefly) presents the whole process of a kind of serious ecological and environmental hazard caused by sudden reactivation and sharp release of long-term accumulated pollutant from stable species to active ones in soil or sediment system due to the change of physical-chemical conditions (such as temperature, pH, Eh, moisture, the concentrations of organic matters, etc.) or the decrease of environment capacity. The characteristics of DGH are discussed. The process of a typical DGH can be expressed as a nonlinear polynomial. The points where the derivative functions of the first and second orders of the polynomial reach zero, minimum and maximum are keys for risk assessment and harzard pridication.The process and mechanism of the hazard is due to the transform of pollutant among different species principally. The concepts of "total releasable content of pollutant", TRCP, and "total concentration of active specie", TCAS, are necessarily defined to describe the mechanism of DGH. The possibility of the temporal and spatial propagation is discussed. Case study shows that there exists a transform mechanism of "gradual release" and "chain reaction" among the species of the exchangeable and the bounds to carbonate, iron and manganese oxides and organic matter, thus causing the delayed geochemical hazard.  相似文献   

南半球对流层气候年代际变化及其与太阳活动的联系   总被引：7，自引：0，他引：7  

曲维政  陈璐  黄菲  张微  朱小洁  邓声贵  杜凌 《地球科学进展》2005,20(7):794-803

通过南半球对流层温度场谱分析和逐次滤波分析发现，南半球对流层大气温度场半个多世纪以来呈现明显的持续升温趋势，升温幅度由低层到高层逐步增加，其中地面层1 000 hPa年升温率为0.013℃/a，对流层中部500 hPa年升温率为0.019℃/ a，对流层上部300 hPa年升温率为0.036℃/ a；滤除南半球大气温度场的趋势变化，发现南半球大气温度场从地面层直至对流层顶广泛盛行着十分显著的与太阳磁场磁性22年周期变化相一致的变化周期。太阳磁场磁性周期变化趋势略有超前，分析认为，这是南半球对流层大气气候系统对太阳磁场周期性变化的响应。进一步分析还发现，南半球从地面层1 000 hPa到对流层顶，再到平流层中部10 hPa各层次大气温度变化22年周期分量振荡位相基本一致，周期振幅由低层到高层迅速增大，说明太阳磁场变化对对流层高层比低层影响大，对平流层影响更大。其中地面层1 000 hPa温度场的22年变化周期是在滤除趋势变化和11年周期之后才显现出来的，所以太阳磁场磁性周期变化对地面层气候的影响较小并且经常处于被掩盖状态；南半球地面层1 000 hPa温度场滤除趋势变化之后显示出十分显著的与太阳活动11年周期相一致的变化周期，分析认为，这是南半球对流层大气气候系统对太阳活动11周期性变化的响应。对流层上层300 hPa温度场滤除趋势变化和22年周期之后也显示出11年变化周期，而对流层中部500 hPa则无此周期反应，说明太阳活动11年周期对地面层1 000 hPa大气气候影响最明显，对流层中上层影响较弱。  相似文献   

河南内乡-淅川-带的虎睛石矿床及开发利用     

刘国范  杨振军李铭 马庚杰 《华南地质与矿产》2005,(1):68-71

研究区虎睛石矿床在地质特征、矿物组合、化学成分及琢雕效果等方面与国外虎睛石矿床是完全不同的，属于一种特殊的罕见类型。在分析虎睛石地质特征、开发利用现状的基础上，认为该区的虎睛石资源丰富，琢雕效果好，在国内外市场上具有一定的竞争力和良好的开发利用前景。  相似文献   

The dynamic characteristics and migration of a pyramid dune   总被引：6，自引：0，他引：6  

TAO WANG  WEIMIN ZHANG  ZHIBAO DONG  JIANJUN QU  ZHEFAN JING  WANFU WANG  JIANMIN FENG 《Sedimentology》2005,52(3):429-440

The results of wind tunnel experiments and field observations show that when the intersection angle between airflow direction and dune crest (ridge) line is > 30°, a reverse vortex is formed. Because of the convergence of sand streams from the windward and lee slopes at the crest, sand accumulates in the crestal region, causing vertical growth. Nevertheless, studies also show that the common asymmetry of the two slopes of a dune may significantly influence the evolution of arms of a pyramid dune. The migration rates of pyramid dunes are mediated by the interplay of their arms moving transversely and the vertical growth in response to the variations in wind regimes. Comparing the effects of airflow transverse to a given arm with longitudinal airflow, it is indicated that the transverse airflow is more significant in controlling the arms of pyramid dunes. The whole body of the studied pyramid dune, particularly the upper quarter section, migrated SE direction during the monitoring period. The patterns of wind erosion and deposition change alternately with seasonal variations in wind directions. The W, NE and SE sides undergo constant erosion, deposition and both erosion and deposition, respectively. The results of long-term monitoring of a pyramid dune show that southerly winds, resulting from a local circulation, markedly affect the transverse migration of the whole pyramid dune.  相似文献   

北京石花洞地区奥陶纪灰岩36Cl侵蚀速率初探     

晁念英  潘欢迎  刘存富  万军伟  王佩仪  姜山  何明  武绍勇 《地球学报》2005,26(Z1):272-274

本文根据理论上灰岩中36Cl的5个来源，论述了36Cl在灰岩深度剖面上的4个分布特征，描述了36Cl的采样方法和AMS的分析技术。计算出北京石花洞地区奥陶纪（O2）灰岩的表面侵蚀速度（ε=17.40μm/a）。  相似文献   

沙漠沙丘污水处理系统:原理、方法和效果   总被引：1，自引：0，他引：1  

陈明  刘晓端  陈鸿汉  曹晓娟 《地学前缘》2005,12(Z1):67-72

“沙漠沙丘系统(DDS)”是以地球化学工程学原理为指导的特殊水处理系统,它利用沙漠沙作为滤料,通过“机械过滤”、“化学作用”和“生物作用”净化污染水,一方面可使沙丘变得湿润而不再移动,以固定移动沙漠;另一方面又能净化污染水,最终起到“以害克害、固沙治水、一举多得”的良好综合生态环境效应。DDS是绿色的水处理系统,所需的原料和生成物都属于自然界存在的物质,无二次污染的发生。在DDS设计中,要注意的主要因素应包括:滤料的种类、湿干时间比、微生物培养方式、滤料层厚度、进水水质、时间、温度和pH等。DDS可以把官厅水库水由V类和超V类处理成2~3类水,从而恢复官厅水库的饮用水功能。  相似文献