玉树地震前的地下流体观测井温度数据超差异常及其与地震关系研究     

李滔  马建新  樊春燕  邱鹏成  姚家骏 《中国地震》2012,28(3):328-334

本文收集整理了距2010年4月14日玉树7.1级地震震中700km范围内的全部13个地下流体观测井孔的温度观测资料,统计分析了2008年5月以来各井温度当月超过3倍均方差的数据个数(以下简称月超差个数).结果发现,在玉树地震前6个月,13个观测井中有10个井观测数据出现月超差个数升高现象,有4个观测井月超差个数出现了同震升高和震后升高现象.2008、2009年大柴旦发生的2次6级以上地震前,也有类似现象.此异常现象可能反映了玉树地震前场兆和源兆的共同作用过程.  相似文献   

Evaluation on Groundwater Resources of Medium Salinity in Tarim Basin and Development and Demonstration of Under-mulch-drip Irrigation Technology for Cotton          下载免费PDF全文

Qiao Li  Jin-long Zhou  Shun-jun Hu  Bin-guo Wang  Rui-liang Jia 《地下水科学与工程》2013,1(3):10-21

The groundwater of medium salinity refers to the groundwater with a mineralization degree of 2-7 g/L that can be directly or indirectly used for irrigation. This paper determined the distribution area of the groundwater with medium salinity in Tarim Basin, estimated the total amount of recharge resources and exploitable quantity of the groundwater of medium salinity. The irrigation water quality assessment was conducted on the groundwater of medium salinity by using multiple factors and methods. The salt tolerance parameters and irrigation water mineralization control parameters of the cotton in under-mulch-drip irrigation were determined. The under-mulch-drip irritation technology for cotton in groundwater of medium salinity was developed and applied successfully to the demonstration area. The social, economic and ecological effects of this technology as well as the application prospect were analysed. This paper also puts forward two questions that need to be further studied  相似文献   

Treatment of Arsenic Contaminated Groundwater Using Calcium Impregnated Granular Activated Carbon in a Batch Reactor: Optimization of Process Parameters     

Prasenjit Mondal  Bikash Mohanty  Chandrajit Balomajumder 《洁净——土壤、空气、水》2010,38(2):129-139

This paper is an experimental investigation into the removal of arsenic species from simulated groundwater by adsorption onto Ca²⁺ impregnated granular activated carbon (GAC‐Ca) in the presence of impurities like Fe and Mn. The effects of adsorbent concentration, pH and temperature on the percentage removal of total arsenic (As(T)), As(III) and As(V) have been discussed. Under the experimental conditions, the optimum adsorbent concentration of GAC‐Ca was found to be 8 g/L with an agitation time of 24 h, which reduced As(T) concentration from 188 to 10 μg/L. Maximum removal of As(V) and As(III) was observed in a pH range of 7–11 and 9–11, respectively. Removal of all the above arsenic species decreased slightly with increasing temperature. The presence of Fe and Mn increased the adsorption of arsenic species. Under the experimental conditions at 30°C, the maximum percentage removals of As(T), As(III), As(V), Fe, and Mn were found to be ca. 94.3, 90.6, 98.0, 100 and 63%, respectively. It was also observed that amongst the various regenerating liquids used, a 5 N H₂SO₄ solution exhibited maximum regeneration (ca. 91%) of the spent GAC‐Ca.  相似文献   

Definition and interests of reciprocity and reciprocity gap principles for groundwater flow problems     

Nejla T. Hariga  Amel Ben Abda  Rachida Bouhlila  Jean-Raynald de Dreuzy 《Advances in water resources》2010

We introduce the reciprocity and reciprocity gap principles for flow problems in hydrogeology and illustrate their interest in addressing identification problems. The reciprocity principle is derived from mechanics and establishes for flow problems a relationship between different sets of forcing terms, including sources, sinks and boundary conditions, and the resulting head fields. The reciprocity gap principle compares different head fields resulting from the same forcing terms applied to different structures. We give general 2D expressions of the reciprocity and reciprocity gap principles for transient flow problems and give two examples of applications for the identification of transmissivity values and interfaces between different transmissivities. Identification capacities of the reciprocity and reciprocity gap principles yielding direct inversion methods could be used as initial guesses for more advanced inverse problem methodologies.  相似文献   

Using geophysical methods to define the attitude and extension of water-bearing strata in the Miocene sediments of the Pannonian Basin   总被引：1，自引：0，他引：1  

Milenko Burazer  Vicko itko  Dane Radakovi&#x;  Miodrag Parezanovi&#x; 《Journal of Applied Geophysics》2010,72(4):242-253

  相似文献   

中高频带地下水位对气压和固体潮的响应特征分析   总被引：1，自引：0，他引：1  

来贵娟  黄辅琼 《地震》2010,30(2):80-88

我国前兆观测网络数字化改造的完成, 使得对地震地下水位观测的孕震信息提取和干扰因素排除的研究拓宽至更广的频率范围, 而对原有一些认识的重新考察也成为可能。 本文从中国地震前兆台网挑选出数据质量较好的10个台站, 分析各个台站2008年1月1日至5月11日的地下水位和气压资料及理论重力固体潮的频谱及其频域相关性特征, 并分析了地下水位对气压响应的时移。 结果表明, 中高频带地下水位对气压的响应没有低频带好, 两者相关性随周期的减小而减弱; 含水层岩性对中高频带地下水位的气压和固体潮响应特征有较大影响, 部分灰岩井在高频频段存在地下水位对气压响应异常的现象; 时移效应对水位的气压响应整体特征影响不大, 体现出两种信号自身的复杂性。  相似文献   

Aeromagnetic and Landsat TM structural interpretation for identifying regional groundwater exploration targets, south-central Zimbabwe Craton     

R.T. Ranganai  C.J. Ebinger   《Journal of Applied Geophysics》2008,65(2):73-83

Aeromagnetic (AM) and Landsat Thematic Mapper (TM) data from the south-central Zimbabwe Craton have been processed for the purpose of regional structural mapping and thereby to develop strategic models for groundwater exploration in hard-rock areas. The lineament density is greater on TM than on AM images, partly due to the resolution of the different datasets, and also because not all TM lineaments have a magnetic signature. The derived maps reveal several previously undetected lineaments corresponding to dykes, faults, shear zones and/or tectonically-related joints, striking predominantly NNE, NNW and WNW. We suggest the possible hydrogeological significance of some of these patterns as follows: the aeromagnetic data can be used to map faults and fractures of considerable depth which are likely to be open groundwater conduits at depth (typically under tension), while TM lineaments, although not necessarily open (mostly under compression), represent recharge areas.The interpreted persistent lineation and well developed fracture patterns are correlated with existing boreholes and indicate a spatial relationship between regional structures and high borehole yields (> 3 m³/h). This relationship is combined with other lithological and hydrogeological information to identify potential regional groundwater sites for detailed ground investigations. These are defined as dyke margins, faults, fractures/joints or intersections of any combination of these structures. Priority should be given to coincident AM/TM lineaments (e.g., NNW and NNE fractures) and continuous structures with large catchment areas (e.g., NNE and WNW faults). The late Archaean (2.6 Ga) granites are considered the most favourable unit because of their associated long and deep brittle fractures between numerous bornhardts (inselbergs) and kopjes. Several small-scale TM lineaments also form important local sources of groundwater for hand-dug wells. Based on measured rock susceptibilities from the area, we present a model of the typical magnetic responses from the possible groundwater exploration targets. The developed magnetic model could be applicable to similar terrains in other Archaean Cratons.  相似文献   

Contribution of magnetic resonance sounding to aquifer characterization and recharge estimate in semiarid Niger   总被引：4，自引：0，他引：4  

J.M. Vouillamoz  G. Favreau  S. Massuel  M. Boucher  Y. Nazoumou  A. Legchenko 《Journal of Applied Geophysics》2008,64(3-4):99-108

To improve the knowledge of the regionally important Continental Terminal 3 (CT3) aquifer in south-western Niger, fifteen magnetic resonance soundings (MRS) were carried out in December 2005 in the vicinity of wells and boreholes. The output MRS geophysical parameters, i.e. water content and decay constants versus depth, were compared to hydrogeological characteristics, i.e. water table depth, total porosity, specific yield and transmissivity estimated from direct measurements, pumping tests and transient groundwater modelling. The MRS-determined parameters were then used to estimate the rates of groundwater recharge.Contained in poorly consolidated Tertiary sandstones, the CT3 aquifer's water table has continuously risen by 4 m in total over the past four decades. Additionally, a significant portion of this increase has occurred in the past decade alone, with an annual rise now ranging between 0.1 and 0.3 m depending on the monitored well. Increase in groundwater recharge due to land clearance and deforestation explains this situation. According to previous estimations, the pre-clearing recharge ranged from 1 to 5 mm per year in 1950–60 s, while more recent recharge rates (1990s–2000s) range from 20 to 50 mm per year. These recharge values are directly affected by estimated aquifer specific yield value, while the spatial variation of rates of water table rise can be attributed to large scale hydrodynamic heterogeneities in the aquifer. However, few field measurements were available to confirm these assumptions.The main results of this study are: (1) The water table depth and aquifer transmissivity are estimated from MRS output parameters with an average accuracy of ± 10% and ± 9% respectively. (2) The MRS-determined water content is linked to both the total porosity and the specific yield of the aquifer, but no quantitative formulation can be proposed as yet. (3) Using the average MRS-determined water content over the investigated area, i.e. 13%, the groundwater recharge rates can be estimated to be ~ 2 mm per year in the 1950–1960s (pre-clearing period), and ~ 23 mm per year for the last decade. (4) The variations in specific yield and transmissivity cannot explain by themselves the spatial variability of the rise of the water table. (5) The ranges in transmissivity and water content obtained from MRS are more realistic than the groundwater modelling outputs. Therefore, MRS could be used to better constrain the aquifer parameters in groundwater modelling with a dense site network.Finally, this work illustrates how MRS can successfully improve characterisation and transient multi-year groundwater balance of commonly found sedimentary aquifers, particularly when integrated with well observations and pumping tests.  相似文献   

Using a groundwater quality negotiation support system to change land-use management near a drinking-water abstraction in the Netherlands     

Cors van den Brink  Willem Jan Zaadnoordijk  Bas van der Grift  Peter C. de Ruiter  Jasper Griffioen 《Journal of Hydrology》2008,350(3-4):339-356

A negotiation support system (NSS) was developed to solve groundwater conflicts that arose during land-use management. It was set up in cooperation with the stakeholders involved to provide information on the impact of land use, e.g., agriculture, nature (forested areas), recreation, and urban areas, on the quality of both infiltrating and abstracted groundwater. This NSS combined simulation programs that calculate (1) the concentrations of nitrate in shallow groundwater for each land-use area and (2) the transport of nitrate in the groundwater-saturated zone. The user interface of the NSS enabled scenario analyses. The NSS was validated at a drinking-water abstraction near Holten (the Netherlands) using a spatial planning process aimed at sustainable land-use and groundwater-resource management. Two land-use scenarios were considered: a base scenario reflecting the autonomous development and an adapted land-use scenario. The calculated results for shallow groundwater provided an explicit spatial overview of the impact of historical land use and N application on the quality of abstracted groundwater as well as insight into the impact of changes in land use and N application. Visualization of the conflicting interests of agriculture and the drinking-water abstraction helped all stakeholders accept the necessary changes in land use identified by the adapted land-use scenario of the NSS. These changes were included in the preferred land-use management option in the regional planning process, which has since been formalized. The NSS provided system insight, scoping analyses, and education, in addition to generating quantitative information on the impact of land-use functions on groundwater quality.  相似文献   

Groundwater discharge along a channelized Coastal Plain stream   总被引：1，自引：1，他引：0  

Danita M. LaSage  Joshua L. Sexton  Abhijit Mukherjee  Alan E. Fryar  Stephen F. Greb 《Journal of Hydrology》2008,360(1-4):252-264

In the Coastal Plain of the southeastern USA, streams have commonly been artificially channelized for flood control and agricultural drainage. However, groundwater discharge along such streams has received relatively little attention. Using a combination of stream- and spring-flow measurements, spring temperature measurements, temperature profiling along the stream-bed, and geologic mapping, we delineated zones of diffuse and focused discharge along Little Bayou Creek, a channelized, first-order perennial stream in western Kentucky. Seasonal variability in groundwater discharge mimics hydraulic-head fluctuations in a nearby monitoring well and spring-discharge fluctuations elsewhere in the region, and is likely to reflect seasonal variability in recharge. Diffuse discharge occurs where the stream is incised into the semi-confined regional gravel aquifer, which is comprised of the Mounds Gravel. Focused discharge occurs upstream where the channel appears to have intersected preferential pathways within the confining unit. Seasonal fluctuations in discharge from individual springs are repressed where piping results in bank collapse. Thereby, focused discharge can contribute to the morphological evolution of the stream channel.  相似文献