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91.
A survey of soil gas radon concentrations has been carried out at three sites, in the seismic area of Armenia, from 1996 to 1999. The seismicity generates opposed behaviours at the different sites. This heterogeneity is related to the sites locations in the tectonic frame. An increase of radon concentration occurs inside the tectonic micro-blocks during local seismic activity. On the contrary, an abrupt co-seismic decrease is recorded close to the fault area. These variations can be due to ‘pore-collapse’ phenomena which expulse the pore-gas and increases Rn concentration in soil at intra-blocs sites, but also to pore-elastic deformations and microfracturing modifications in the fault area. To cite this article: K. Kharatian et al., C. R. Geoscience 334 (2002) 179–185.  相似文献   
92.
海岛是一种独特的生态系统, 由于其特殊的水文地质条件, 水资源相对比较贫乏, 一般都依靠地下水维持岛上生产生活用水, 如果地下水质受到影响, 则会带来较大的风险。岛内地表淡水湖泊水体污染严重。为了解决岛内地表淡水湖泊水体污染问题, 决定调用海水对其进行稀释, 而这一方案则有可能造成引水工程沿线海水侵入地下水问题。本文采用有限元方法分析从厦门西侧的筼筜湖经松柏湖调水到钟宅湾对周围地下水质和湖库水体的影响, 以及在丰水年和枯水年湖库水体和海水水体之间的补给关系。分析表明: 工程在一年左右对周围地下水的影响将趋于稳定, 工程沿线150~800m 范围内地下水的盐度产生了明显变化。在枯水年, 由于地下水位下降, 海水有可能会补给湖库, 引起湖泊盐度升高, 对工程沿线特别是饮用水备用水源湖边水库造成潜在的威胁。  相似文献   
93.
上海深部硬土渗透特性试验研究   总被引:1,自引:1,他引:0  
上海深部硬土层的沉降显著滞后于水位变化, 本文通过一系列渗透试验进行了相关问题的研究, 包括初始水力坡度, 结核对渗透性的影响, 压力对渗透性的作用, 以及孔隙比与渗透系数之间规律的研究。结果表明硬土的渗透速率与水力坡度之间符合良好的线性关系, 满足达西定律; 大量的致密结核对渗透性影响微弱; 应力增加导致渗透性降低, 渗透系数与孔隙比呈指数规律变化。基于试验成果评价了1989~2007年天然硬土的渗透性变化, 此期间硬土层边界水位下降了近30m, 硬土层的沉降造成了该层渗透性的降低, 但土层的平均渗透系数改变不大。  相似文献   
94.
江苏省地质灾害与防治探讨   总被引:2,自引:1,他引:1  
江苏省地质灾害类型除地震外,主要有地面沉降,滑坡,地下水水质恶化,地面塌陷等几种,地面沉降是因为长期过量开采地下水而引起,主要发生在苏州,无锡和常州,滑坡多为人类工程活动使土体稳定性遭到破坏所致,主要发生在南京和镇江地区;地下水水质恶化是因过量集中开采地下水所致,主要发生在苏州,无锡,常州,南通和徐州地区,地面塌陷是由矿区地下水疏干而造成,主要发生在铜山县,南京和徐州等地的煤矿采空区,江苏地质灾害  相似文献   
95.
The Cretaceous age Chalk of south east England forms an important aquifer. Within chalk the storage and transmission of groundwater is enhanced by subsurface karstic weathering. The case study presented in this paper demonstrates that current approaches to assessing groundwater vulnerability to pollution and delineating source protection zones are flawed, as they do not take proper account of the karstic nature of chalk.Improved techniques, based on understanding the geological and geomorphological controls of karst development in chalk, are proposed to overcome the shortcomings of published groundwater vulnerability maps. The results also demonstrate the inadequacies of current groundwater modelling approaches for defining source protection zones. The techniques follow European Commission research recommendations by taking account of recharge, presence of overlying cover deposits, the nature of chalk karst and the way in which it influences the flow of groundwater. The approach described allows for better informed decisions to be made about chalk aquifer management to ensure adequate protection and conservation of groundwater. For example, the published groundwater vulnerability map shows Lambeth Group deposits classified as being a minor aquifer of low groundwater vulnerability in the chosen study area. However, by applying the new techniques, they are classified as having an Aquifer Vulnerability Rating of moderate to very high, when taking the karstic development of the underlying chalk into account.  相似文献   
96.
Geological relationships, hydrogeology and chemical composition of ground water in northern Banat were studied through the period 2000–2004 using the available background data from published and unpublished sources. Northern Banat is the extreme northeastern part of the Republic of Serbia and a geotectonic part of the vast Pannonian depression. The source of domestic and industrial water supply is only groundwater from artesian and subartesian aquifers of Lower Pleistocene (Q11) and Upper Pleistocene (Pl32) sand deposits. The ground water, “peculiar” in chemical composition, is the only source of drinking water in the arid area. A notable variation in the chemical composition of artesian waters within the same geotectonic unit (Pannonian basin), abstracted for municipal water supplies of Kikinda, Novi Knezevac and Djala, has attracted attention of these authors. Our paper attempts to interpret the variation in the chemical composition of ground water and the cause of the variation by the interaction of ground water and rocks forming the aquifers on the case example of the water supply sources for the three mentioned towns. With respect to the depth and lithology of the aquifers, we interpret the varied chemical compositions of waters in the mentioned sources as a consequence of natural factors (geological environment), geological relationships and hydrogeological conditions.  相似文献   
97.
Groundwater vulnerability and risk mapping is a relatively new scientific approach for facilitating planning and decision making processes in order to protect this valuable resource. Pan European methodology for aquifers vulnerability has recently been developed by assessing all the existing relevant techniques and emphasizing on karstic environments. In the particular study, state-of-the-art methods and tools have been implemented such as remote sensing, isotopic investigations and GIS to map the groundwater vulnerability and pollution risk in a geologically complex area of W. Greece. The updated land use map has been developed from a Landsat 7+TM image elaborated with image analysis software, while the detailed hydrogeologic properties of the area have been recorded with an intensive isotopic study. The local groundwater vulnerability map has been produced following the aforementioned Pan European method, in a GIS environment while the risk map, which was the final product of the study, has been developed after combining the vulnerability and the land use maps. The results indicated that the areas comprised of highly tectonized calcareous formations represented high vulnerability and risk zones while forested areas away from the karstic aquifer illustrated moderate to low vulnerability. Moreover, human activities increase the pollution risk in lowland areas consisting of sedimentary deposits that have been classified as moderate vulnerability. The particular methodology operated efficiently in this study and due to its accuracy and relatively easy implementation can be used as a decision support tool for local authorities.  相似文献   
98.
根据老厂矿区特别是老厂四勘区煤田和煤层气勘探的基础资料,重点评价该区及煤层气的水文地质特征,为煤层气成藏条件研究及煤炭资源开采提供依据。  相似文献   
99.
Dubravsky Massif菱镁矿体的开采产生了部分局限在石炭纪低裂缝渗透变质岩中的喀斯特型裂缝含水层.大量的开矿过程对含水层中的地下水循环和化学成分都造成了可观的变化.本文研究了在这种复杂条件下地下水化学成分变化成因模型.根据化学配位模型,计算出所选矿物的饱和指数,从而指示所有喀斯特裂缝含水层饱和带中的地下水对菱镁矿、白云石、方解石的过饱和度和石膏的不饱和度.假设地下水未受人类活动的污染,而白云石中黄铁矿的氧化对成矿影响甚微,则水化学数据的统计描述代表了含水层中的水文地球化学背景.矿山中矿石焙烧释放的富氮气体凝聚产生的醋酸,能促进菱镁矿和白云石的溶解.这样产生的地下水相对背景值来说则富集NO3,Mg,和TIC.因此,由于地下开矿,岩溶作用估计将是原来的1.5倍.尽管有污染,这些所测参数并没有超过斯洛伐克卫生保健部颁发的No.29/2002 Z.z.饮用水标准临界值.因此采矿后含水层的开采也是可行的.  相似文献   
100.
Numerous geologic processes operate to form the many types of springs in existence today. Karst springs, glacial springs, and thermal springs are reviewed with examples from different parts of the world to emphasize the diversity of their origin. Since Meinzer's classification in 1927, the classification of springs has changed as our understanding of their origin and our scientific knowledge of springs have increased. Today several different classifications have been developed that concentrate on one or more specific characteristics such as size, mineral content, or temperature. A historic sketch of the classification of springs that documents the most common classifications in use is presented. From this historical perspective it is apparent how our understanding of springs, combined with technological advances, will affect future trends in the classification of springs. Eventually a definitive classification of springs, scientific as well as legal, combined with computer data bases, will aid not only in our academic understanding of springs, but in our practical usage. In the late 20th century, there has been increased demand for spring, mineral, and curative waters. Springs, specifically their origin, have become increasingly important. Legislation to protect the rights and safety of consumers regarding springs is forthcoming from state, federal, national, and international organizations. Some current legislation will be highlighted to provide some insight into how exactly these legal rulings affect our use and definitions of springs. The purpose of this paper is to establish the geological/ hydrogeological framework for the diversity of origin and form of springs in addition to providing a historical perspective on classification systems throughout the ages.  相似文献   
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