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长期过量开采地下水,使地下水位持续下降、水质发生变化,动水位观测井断流;地面沉降造成井管上窜,观测管路系统被损坏等,这些现象对地震地下流体观测地震前兆异常的正确判断带来很大困难。应用水文地质理论与方法,分析含水层的水均衡状态、应力-应变状态及其与水位动态的关系,初步探讨了超采区井水位异常性质的理论与方法。结果表明,根据井孔所在区水位下降漏斗的扩散特征,结合以上所提到的理论和方法,依据资料多年变化特征,可以较准确地判断异常的性质。研究结果有助于区分单一集中抽水与长期地下水超采对水位观测的影响,有助于正确识别超采区水位前兆异常,有助于地震分析预报水平的提高 相似文献
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针对2008年汶川MS 8.0地震后江苏地区的地震观测井水位上升现象,选取了苏18井和井周边地表水进行了水化学和物理分析,研究了井水位异常与地表水和大气降水的补给关系,讨论了井水补给来源及其与高邮-宝应MS 4.9地震的关系。离子含量和氢氧同位素结果表明,苏18井水主要为大气降水成因,存在一定的水岩作用。应用氯离子分析降水对地下水的补给,其结果显示大气降水在井水补给源中占了重要份额,井水位的突然上升与同期降水量增加有一定关系。水库水与苏18井水之间存在水力联系,大气降水增多致使水库水位升高,对该井水位变化有一定的影响。综合分析认为,大气降水的增多致使水库蓄水增加,水库水通过侧向渗透补给造成了2011年苏18井的水位显著升高。苏18井异常不是由构造活动引起的,作为高邮-宝应MS 4.9地震的前兆依据不充分。水化学和物理结合的方法为今后判别地下水位异常干扰提供了依据。 相似文献
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结合观测井孔的水文地质条件、大气降水资料 ,深入剖析了华北地区水位、水氡的中期和转折型短期异常变化的直接原因 ,认为水位异常是由于降水量的增大与减少造成的 ,其形成机制主要为降水渗入补给 ;水氡异常的形成原因主要为降水渗入 -混合机制。进而提出“深浅构造的互动作用” ,用以解释流体异常与地震的关系 ,其论点是 :降水、地下水变化可诱发 (活化 )浅层的构造变动 ,而浅层构造活动又引发深部构造活动和地震的发生 ;反之 ,深部构造的活动和地震的孕育 ,使浅层岩石的应力增强 ,在降水、地下水的诱发作用下 ,可导致浅层的构造活动。降水引起的地下水异常是一种广义的地震前兆 相似文献
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Mingbo Yang Yuehu Kang Qing Zhang Institute of Geographic Sciences Natural Resource Research Chinese Academy of Sciences Beijing China Graduate University of Chinese Academy of Sciences Beijing China Earthquake Administration of Beijing Municipality Beijing China Beijing Beifang Middle School Beijing China 《地震学报(英文版)》2009,(3):301-306
This paper quantitatively analyzed groundwater table fluctuations caused by groundwater overdraft, and probed into the possibility of drawing earthquake precursory information from groundwater table variations on the background of groundwater overdraft. Main effect factors of groundwater regime in Beijing region include groundwater extraction and rainfall. The decline of groundwater table was directly related to regional groundwater overdraft. Using the method of correlation analysis, the paper analyzed the... 相似文献
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地下水位中地震前兆信息提取方法研究 总被引:1,自引:0,他引:1
地下水位观测值的影响因素包含降雨、气压、固体潮、地质构造作用等.为凸显地质构造作用对地下水位的影响,需要滤除降雨、固体潮、气压等因素的影响量.本文首先分离地下水位受固体潮、气压作用的影响量;然后依据降雨影响地下水位可以分为长期和短期变化的思路,利用基流分割方法对地下水位的两种变化进行分离,确定地下水位的降雨影响量;最后分析各分量异常与地震活动性关系,探查其中包含的地震前兆信息.本文的研究思路为地下水位观测值中地震前兆信息研究提供了一套可供尝试的系统技术方法. 相似文献
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天津潘庄井水位异常与地震关系的分析 总被引:1,自引:1,他引:0
利用地下水进行地震预报和研究有比较明确的物理基础。长期的地下水观测记录了大量的震例。天津地下水观测网含盖了不同的含水层,其中咸水层占有一定的比例。本文以宁河潘庄咸水井为例,对其出现的异常资料进行了系统分析,统计了异常与地震的对应关系,总结了该井水位的映震特征。结果表明,异常形态均属于突升一缓降的阶变型异常,具体表现出两种映震类型:①水位突升一水位转折下降一发震;②水位突升一水位转折下降一恢复到原水平一发震。上升幅度在几米以上,震后逐渐恢复;异常时间分布散,但异常超前时间仍以半年居多;异常幅度有随震级增高而增大、随震中距增大而减小的趋势等特点。 相似文献
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依据 《中国震例》 资料,统计分析了云南地区1966—2006年MS≥5.0地震的地下流体测项异常,结果表明:超过70%的水位和水温震前异常表现为上升,水氡和水位异常出现时间最早;震级越大相应的流体异常范围就越大;大多数震前流体异常会持续到地震发生,说明流体异常与震前地壳活动有关,并据此得出云南地区地震发生时间及异常检测井至震中距离的经验性边界方程。分类汇总云南地区地下流体测项的异常形态,识别出该地区地下流体异常的5种主要异常形态,即趋势转折类、周期类、突变类、阈值类和综合类,并举例阐明了各种异常形态的特征及其可能的成因。本文研究结果对于认识云南地区流体异常特征以及提升流体异常应用水平具有一定的参考意义。 相似文献
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中国地震地下流体观测经过数字化改造以后, 观测资料的采样频率显著提高。 流体观测资料中的高频数据含有丰富构造信息, 为我们捕捉地震孕育及发生过程中的前兆异常信息提供了有利条件。 但是, 高频信息的出现激发了对数据分析方法改变的需求, 如何研发与数字化高频观测资料相匹配的数据处理和异常识别方法, 从高频观测数据中挖掘潜在的前兆异常信息, 成为目前地震地下研究者首要需解决的关键问题。 应用概率密度分布法对2014年鲁甸6.5级地震前南北地震带174组水位、 水温分钟值高频观测数据进行分析, 结果显示: 鲁甸6.5级地震前共有10个水位测点和7个水温测点出现高频信息异常, 异常多集中在滇西南构造带的滇中次级块体两侧, 且随着时间推移, 有向震中区逼近的变化特征。 通过对震源区及附近地区地壳结构、 构造应力作用及更大范围的区域动力演化特征进行分析, 发现异常信息的空间分布特征与川滇地区地壳运动场具有很好的一致性, 说明概率密度分布可有效反映出区域构造应力作用, 同时也验证了利用概率密度分布在流体观测数据的高频信息异常提取方面具有一定可靠性。 相似文献
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Yaguang Zhu Yuanzheng Zhai Qingqing Du Yanguo Teng Jinsheng Wang Guang Yang 《水文研究》2019,33(6):945-961
Riverbank filtration (RBF) has been widely used throughout the world as an effective means to regulate surface water and groundwater resources and pretreat raw water for municipal water supply. The quality of the water from a riverside well field and the mixing ratios of surface water and groundwater is primarily impacted by the hydrodynamic processes in the RBF system. The RBF system is largely controlled by the water exploiting system in addition to the natural hydrologic condition of the river–aquifer system. As one of the most important design parameters of the riverside well field, the drawdown of groundwater level greatly determines the water head differences between the river water and groundwater as well as the field flow net, which subsequently impacts the mixing of river water and groundwater and water quality significantly. This study aimed to improve the understanding of the mixing process between the surface water and groundwater and estimate the impact of the RBF on the mixing ratio of surface water–groundwater and water quality quantitatively. A set of field pumping tests with various groundwater level drawdowns were carried out independently and successively at a riverside field with a single pumping well near the Songhua River in Northeast China in August 2017. During these tests, the water levels and hydrochemical parameters of the Songhua River, the adjacent aquifer, and the pumping well were monitored. The dynamic mixing process of the river water and groundwater and water quality under various drawdown conditions were analysed systematically using analytical methods. The results obtained from Dupuit method and the Mirror Image method in conjunction with the Hydrochemical Tracing method showed that the pumping water directly from the river water reached 60% ± 10% after a steady flow net was established. The larger the proportion of the pumping water captured from the river, the better quality of the pumping water was, because the quality of the river water (only limited to some water quality parameters monitored which were minority) was better than that of the groundwater. The results also showed that total Fe, TDS, total hardness, CODMn, and K+ were relatively sensitive to the changes of groundwater drawdown, and their concentrations decreased with an increase in the groundwater drawdown. It can be concluded that both the mixing ratio of the surface water and the groundwater and the water quality of the riverside well field can be regulated through adjusting the designed drawdown of the groundwater level, which is helpful for the design and the optimization of the riverside well water intake engineering. 相似文献
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The largest and most disastrous earthquake in Taiwan (Mw: 7·3) in the 20th century, the Chi‐Chi earthquake, hit central Taiwan at 01:47 local time on September 21, 1999. The groundwater level changes were rapid at that time. Studies have found that the rapid change in groundwater levels was a co‐seismic phenomenon. This work analyzes the possibility that the abnormal change in groundwater levels may have occurred before the earthquake. Three well stations with a total of five wells are considered. They are all near the Che‐Lung‐Pu fault, which caused the Chi‐Chi earthquake. The time series decomposition method was applied to decompose the seasonal groundwater level, the trend in groundwater levels, and the period of the change in the groundwater level. Residual groundwater levels were found by subtracting the determined seasonal, trend and period data from corresponding data for the original groundwater level. The computed residual water levels in July, August and September of 1999, were transformed into a frequency spectrum by a Fourier method. Additionally, the effects of barometric pressures on the groundwater level changes were also evaluated. Analytical results show that the spectral density functions of the irregular groundwater level in the confined aquifer at the Chu‐Shan well in September behaved differently from those in July and August. We posit that a pre‐seismic hydrogeological anomaly may have existed before the Chi‐Chi earthquake, and can be considered in future studies of anomalies associated with earthquakes. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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