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震前井孔水位异常的报道,国内外已屡见不鲜,本文介绍的是1984年11月北京塔院井捕捉到的一组典型的异常实例,包括水位的趋势异常,水位与气压的正相关异常、短临突降及水位固体潮畸变等。 塔院井位于著名的深大断裂—黄庄—高丽营断裂带的中段,井深361米,观测层为中侏罗系凝灰岩裂隙承压含水层。通过近十年的观测,已查明其正常水位变化的规律,即多年趋势性下降的背景上年变规律清晰,较清楚地记录到水位固体潮、水震波、气压效应及降雨荷载效应等多种地壳应力应变微动态信息。表明,该井井位好,对地壳活动的反映能力较强,已弄清正常动态特征,具有捕捉地震前兆异常信息的可能性和有利条件。 相似文献
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本文以蚌埠监测中心井2017—2020年水位10次明显的长时间持续升高为研究对象,选取10次水位升高前后不同时段的降雨量进行多元回归分析,建立多元回归方程。结果显示,2017—2020年水位10次明显的长时间持续升高主要与上升期间降雨量关系显著,与其他降雨参数关系不显著。结合蚌埠周边ML2.5以上地震目录分析结果认为,水位长时间持续升高的规律与地震频次发生规律相对应,说明降雨和区域应力场变化共同影响了蚌埠监测中心水位的变化。 相似文献
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本文针对2016年6—9月天津王3井出现的井水位高值异常现象进行了异常机理分析。首先,利用频谱分析法提取了水位年动态并与区域降水量进行相关分析,排除降水的影响;其次,采用三阶多项式拟合计算了水位多年动态,定量地识别出王3井的水位年变异常,并取王3井及周边水源进行了水化学分析,结果显示,王3井所处局部区域的地下水主要成因为大气降水,存在一定的水岩作用,与周边水源之间无明显水力联系;最后,结合首都圈地震台站的波速比推测天津王3井所处的局部构造区域内可能存在一次短期应力积累过程。2016年9月10日发生的唐山MS4.2地震缓解了此次局部应力积累,使得王3井内水位逐渐恢复正常年变特征。 相似文献
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《地震地磁观测与研究》2016,(3)
福建地下流体台网布局较为合理,水位、水温测项能观测到较为规律的长期、年、月、日动态,多数指标符合学科规范要求,能记录到较大远震的同震响应波。观测数据质量主要影响因素有降雨、观测环境破坏、观测系统故障等;地下水位动态受降雨影响表现为上升态势,由于降雨的持续时间、强度和面积不同,由降雨引起的水位变化形态也复杂多样;水位和水温同震变化与变化幅度、持续时间明显相关。 相似文献
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1993年太湖流域的洪涝灾害及水利工程的作用 总被引:2,自引:1,他引:1
1993年汛期太湖最高水位高居建国以来的第3位,仅次于1991年和1954年,达到4.51m(平均水位,下同),局部地区发生了洪涝灾害。本文对1993年太湖流域汛期的雨情和水情做了论述,并对1993、1991、1954年三个典型大水年的降雨和洪水特征作了比较。同时,还对洪涝灾害和水利工程的作用进行分析。太湖流域的雨季一般为5—7月,但是1993年汛期的降雨在时间上的分布有些异常。降雨集中在8月,而河道最高水位则出现在8月下旬。降雨的空间分布有以下3个特征:(1)上游地区的降雨集中在浙西山区;(2)太湖湖区的降雨量很大;(3)下游地区的降雨集中在淀泖和杭嘉湖地区。淀泖和杭嘉湖地区一些水位站的实测河道水位,比发生大洪水的1991年还要高。发生洪涝灾害的原因可归纳为,上游地区洪水来量大,当地的降雨强度高,以及下游河道排水不畅通。为了改进防汛调度和完善治理规划,需要对不同典型洪水年份的降雨和洪水模式做进一步研究。 相似文献
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2014年以来,滇南地区高大、开远和易门3口井的井水位出现趋势上升现象。通过开展井孔周边地下水开采情况的调查、降水影响的定量排除、井孔含水层系统应力状态的定量计算、周边区域构造活动的分析以及井孔水体化学组分的分析等工作,认为易门井的水位年动态主要受控于降水,2003年以来的趋势下降和2014年的趋势转折上升与大椿树工业园区的深井开挖抽水密切相关;高大井和开远井的井水位自2014年以来的趋势转折上升现象不完全受控于降水,但与周边地下水的开采亦无直接联系,可能与近几年该区域南北向强挤压为主的构造活动有关。 相似文献
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Effects of afforestation on groundwater recharge and water budgets in the western region of Uruguay
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Uruguay has stimulated the development of its forest sector since the promulgation of Forest Law N° 15 939 in December of 1987. Nevertheless, the substitution of natural grasslands with forest plantations for industrial use has raised concerns regarding hydrological processes of groundwater recharge and water consumption involving evapotranspiration. The purpose of this study is to assess the effects of this substitution approach on water resources. Input data were collected from two small experimental watersheds of roughly 100–200 hectares located in western Uruguay. The watersheds are characterized by Eucalyptus Globulus ssp. Maidenni and natural grasslands for cattle use. Total rainfall, stream discharge, rainfall redistribution, soil water content and groundwater level data were collected. Groundwater recharge was estimated from water table fluctuations and from groundwater contributions to base flows. Seasonal and annual water budgets were computed from October of 2006 to September of 2014 to evaluate changes in the hydrological processes. The data show a decrease in annual specific discharge of roughly 17% for mean hydrological years and no conclusive effects on annual groundwater recharge in the forested watershed relative to the reference pasture watershed. Reduced annual specific discharge is equivalent to the mean annual interception. The computed actual annual evapotranspiration is consistent with international catchment measurements. Reduction rates vary seasonally and according to accumulated rainfall and its temporary distribution. The degree of specific discharge decline is particularly high for drier autumns and winters (32 to 28%) when the corresponding rainfall varies from 275 to 400 mm. These results are of relevance for water resources management efforts, as water uses downstream can be affected. These findings, based on a study period dominated by anomalous wet springs and summers and by dry autumns and winters, oppose earlier results based on 34 years of rainfall and discharge data drawn from Uruguayan large basins. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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本文基于测深反演结果, 通过数值模拟定性分析了地下水位和降雨对周至地电台地电阻率观测的影响; 同时利用褶积算法定量分析了降雨对该台NS向和NE向地电阻率观测的短期影响和长趋势影响.结果表明, 周至地电台地电阻率年变主要由地表薄层介质电阻率季节变化引起, 受地下水位变化影响不明显. 降雨对NS向和NE向地电阻率观测值的影响在短期内与观测结果一致, 表现为增加; 但长期趋势则与观测结果呈负相关关系.根据数值模拟分析认为, 这种变化与降雨及其渗透深度有关.分析结果与实际观测结果一致, 为正确认识周至地电台地电阻率观测与异常判定提供合理的理论依据. 相似文献
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《Journal of Hydrology》2006,316(1-4):233-247
The annual water budget of Lake Tana is determined from estimates of runoff, rainfall on the lake, measured outflow and empirically determined evaporation. Simulation of lake level variation (1960–1992) has been conducted through modeling at a monthly time step. Despite the ±20% rainfall variations in the Blue Nile basin in the last 50 years, the lake level remained regular. A preliminary analysis of the sensitivity of level and outflow of the lake suggests that they are controlled more by variation in rainfall than by basin-scale forcing induced by human activities. The analysis shows that a drastic (40–45%) and sustained (7–8 years) rainfall reduction is required to change the lake from out flowing to terminal (cessation of outflow). However, the outflow from the lake shows significant variation responding to the rainfall variations. Unlike the terminal lakes in the Ethiopian rift valley or the other large lakes of Tropical Africa, at its present hydrologic condition, the Lake Tana level is less sensitive to rainfall variation and changes in catchment characteristics. 相似文献
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昌平台Sacks体应变仪观测曲线年变现象成因研究 总被引:3,自引:0,他引:3
本文系统地研究了北京昌平台Sacks体应变仪观测曲线年动态变化的基本规律,结合井水位、抽水和降雨等实际观测资料,分析后认为,台站附近农田机井季节性抽水和地下水的自然补给是造成体应变年变现象的根本原因,并探讨了体应变与井水位的定量关系和物理机制,同时对地震预测中所关心的“破年变”问题也进行了探讨。 相似文献
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In deeply weathered laterite catchments of the Darling Range in south-western Australia, the direct contribution (i.e., discharge) of permanent groundwater to streamflow has long been considered as minor. Instead, downslope shallow throughflow was thought to dominate, generating more than 90% of streamflow. We used a chemical hydrograph separation approach to estimate annual groundwater discharge for three catchments over periods of up to 39 years, and found that direct groundwater contributions to streamflow were far more variable across catchments and through time than has previously been acknowledged. The estimated proportion of annual streamflow sourced directly from groundwater ranged from 0 to 93% and was related linearly to the size of the groundwater discharge area in the catchment valley floor. In contrast, contributions from shallow sources including shallow throughflow varied primarily and linearly with annual rainfall. However, the response to rainfall was “amplified” in a predictable way by the size of the groundwater discharge area, consistent with the variable source area concept. We derived a functional relationship between catchment annual rainfall-runoff ratio and groundwater discharge area and successfully applied this to a further four catchments, inferring that the results were broadly applicable across the Darling Range. The implications for an improved understanding of streamflow generating processes in the study region, and for laterite catchments generally, are discussed. 相似文献
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The solar cycle induces strong periodicity in processes underlying monthly rainfall totals. Seasonally varying parameters of rainfall distributions can be estimated with reasonable reliability from relatively few years of monthly data. The distribution of annual totals or maxima in terms of these varying parameters can thus be used to predict long term annual characteristics from quite short records. Specification of seasonal variation of parameters as a harmonic process simplifies the derivations. Ignoring seasonal variation in the rainfall process leads to incorrect estimates of long-term extreme rainfalls when using traditional methodology. 相似文献
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Wavelet analysis of rainfall variation in the Hebei Plain 总被引:5,自引:0,他引:5
XU Yueqing LI Shuangcheng & CAI Yunlong Key Laboratory for Earth Surface Process Ministry of Education Department of Resources Environmental Geosciences College of Environmental Sciences Peking University Beijing China 《中国科学D辑(英文版)》2005,48(12):2241-2250
Rainfall is an important climate factor, which has significant impacts on agricultural production and na-tional economic development[1]. Being part of the North China Plain, the Hebei Plain is an agricultural region. Under the continental monsoon climate, it is cold and dry in winter, hot and rainy in summer, and its variable rainfall is concentrated in summer. Droughts and floods occur frequently and impose sig-nificant impacts on agricultural production. Studies on the characteristics and … 相似文献