怀来2井水氡前兆异常特征分析     

张凤秋 《华北地震科学》2001,19(1):64-66

首先介绍了1998年张北6．2级地震前怀来2井水氡的异常变化，又根据水氡异常与京西地区几次中强震的对应情况，归纳出怀来2井的水氡前兆异常特征；形态为下降一上升型，异常对应范围120－160km；异常出现后28－55d发震等。  相似文献   

土壤氡气异常特征与台湾南投7.6级地震   总被引：4，自引：0，他引：4  

林依再 《地震研究》2001,24(4):321-325

总结了10年来长乐筹东土壤氡气（土氡）观测点所测得的9个3．6级以上地震的土氡前兆异常特征，表明土氡异常具有预报意义。同时着重分析了1999年9月21日台湾南投Ms7.6级地震前该测点4－6月间的土氡异常特征，据此在1999年的半年度会商中提出预报意见。并介绍了7月后该测点的土氡变化特征，认为7－9月间测值的变化是由于降雨过多引起的。  相似文献   

Correlation between geology and radon levels in groundwater, soil and indoor air in Bhilangana Valley, Garhwal Himalaya, India   总被引：2，自引：1，他引：2  

V. M. Choubey  R. C. Ramola 《Environmental Geology》1997,32(4):258-262

 Radon concentrations were measured in soil, air and groundwater in Bhilangana Valley, Garhwal Himalaya, India by using an LR-115 plastic track detector and radon emanometer. Radon concentrations were found to vary from 1 KBq/m³ to 57 KBq/m³ in soil , 5 Bq/l to 887 Bq/l in water and 95 Bq/m³ to 208 Bq/m³ in air. The recorded values are quite high due to associated uranium mineralization in the area. Radon concentration was also found to depend on the tectonic structure and geology of the area. Received: 22 July 1996 · Accepted: 8 January 1997  相似文献   

Mapping radon-prone areas - a geophysical approach     

Shirav M.  U. Vulkan 《Environmental Geology》1997,31(3-4):167-173

 Radon-prone areas in Israel were mapped on the basis of direct measurements of radon (²²²Rn) in the soil/rock gas of all exposed geological units, supported by the accumulated knowledge of local stratigraphy and sub-surface geology. Measurements were carried out by a modified alpha-track detection system, resulting in high radon levels mainly in rocks of the Senonian-Paleocene-aged Mount Scopus Group, comprised of chert-bearing marly chalks, rich in phosphorite which acts as the major uranium source. Issues of source depth, seasonal variations and comparison with indoor radon levels are addressed as well. This approach could be applied to other similar terrains, especially the Mediterranean Phosphate Belt.  相似文献   

Radon modelling and the heat transfer surface area of the British hot dry rock geothermal reservoir     

N. Hussain 《Journal of Earth System Science》1991,100(1):1-11

A simple thermal model is developed to evaluate the heat exchange surface area of a hot dry rock geothermal reservoir. This model, in conjunction with the Rn model of Andrews and coworkers, is applied to RH12/RH15 system of the British HDR reservoir. Results suggest that although the estimated Rn transfer surface area represents the actual swept surface area, it is between 25 and 45 times larger than the heat transfer surface area. The difference is explained as due to clustering of several fractures within a range of thermal interaction, over the duration of the circulation. It is also shown that the decline in the measured temperatures of circulation fluids since 1985 to the present is consistent with the heat exchange surface area going through a maximum in 1987.  相似文献   

Variations of electric resistance and H2 and Rn emissions of concrete blocks under increasing uniaxial compression     

Chi-Yu King  Guangwei Luo 《Pure and Applied Geophysics》1990,134(1):45-56

Electric resistance and emissions of hydrogen and radon isotopes of concrete (which is somewhat similar to fault-zone materials) under increasing uniaxial compression were continuously monitored to check whether they show any pre- and post-failure changes that may correspond to similar changes reported for earthquakes. The results show that all these parameters generally begin to increase when the applied stresses reach 20% to 90% of the corresponding failure stresses, probably due to the occurrence and growth of dilatant microcracks in the specimens. The prefailure changes have different patterns for different specimens, probably because of differences in spatial and temporal distributions of the microcracks. The resistance shows large co-failure increases, and the gas emissions show large post-failure increases. The post-failure increase of radon persists longer and stays at a higher level than that of hydrogen, suggesting a difference in the emission mechanisms for these two kinds of gases. The H₂ increase may be mainly due to chemical reaction at the crack surfaces while they are fresh, whereas the Rn increases may be mainly the result of the increased emanation area of such surfaces. The results suggest that monitoring of resistivity and gas emissions may be useful for predicting earthquakes and failures of concrete structures.  相似文献   

扬州市地质构造背景与氡浓度之间关系分析   总被引：2，自引：2，他引：0  

宋意勤  孙桂石  王振友  吴新明 《上海国土资源》2010,31(Z1)

本文通过对扬州市区地层岩性、地质构造、断裂及放射性元素氡的特性分析,阐明了地区地层岩性、地质构造、断裂与放射性元素氡的形成和运移之间存在的关系,为地区建设工程氡浓度检测与控制提供依据。  相似文献   

Features　of　fractal　dimension　anomaly　of　radon　content　in　underground　water　in　North　China　before　and　after　the　1976　Tangshan　earthquake     

杨长春  陈党民  王秀莲  张芝霞 《地震学报(英文版)》1995,8(1):119-126

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宝坻王4井水氡高值变化的原因探讨     

唐仲兴  李一兵 《华北地震科学》1995,13(2):74-80

天津市宝坻玉４井从１９８３年４月开始观测水氡，观测值相对稳定。１９９１年１０月２日该井水氡测值出现大于２７．０Ｂｑ／Ｌ的成丛高值突跳，最高值达５７．０Ｂｑ／Ｌ，为正常值的两倍多，水氡值由平稳型变为离散型，至今已两年多时间，高值出现后，天津地震局分析预报中心、监测中心先后组织人员到现场落实达２０多次，做了大量的调查研究和实验工作排除了有关干扰，认为王４井的水氡高值高化主要是附近王２井长期抽水影响的结  相似文献   

Determining the spatial scale of variation in soil radon concentration     

M. A. Oliver  I. Badr 《Mathematical Geology》1995,27(8):893-922

Increasing concern about possible links between emissions of radon and certain types of malignant disease has led to local and regional surveys to measure radon concentrations in the soil and in dwellings. The spatial scale at which radon varies is largely unknown, and so efficient sampling schemes and methods of mapping cannot be selected. To determine the spatial scale of radon variation in the English Midlands we measured radon in the soil using solid-state nuclear track detection in three areas of different geological complexity. In two of them we used an unbalanced multistage sampling scheme with seven stages of nesting: the Hereford survey covered distances from 10 m to 7.5 km, and the Buxton survey distances from 1 m to 3.75 km. The results from the nested surveys suggested that geology exerts a strong control on the variation. Finally radon was measured every 20 m along a 2-km long transect which crossed several lithologies close to Nottingham. The soil radon values changed in an erratic way along the transect. The sample variogram of radon has a substantial nugget variance, suggesting that much of the variation occurred for distances less than the sampling interval. The structure at the longer scale seems to be controlled by the underlying geology. These results have implications for designing further surveys and for selecting a method of mapping. Stratification based on lithology might be the only feasible solution to sampling, estimating and mapping radon concentrations over large areas. Where the locally erratic component of variation is large, estimation by kriging, for example, would confer little additional benefit compared with that by classification.  相似文献