Abstract: In the many years practice of earthquake analysis and prediction,it has been noticed that the overexploitation of underground water would cause changes in environmental geology,thus having obvious impact on the water level regime.The overexploitation of underground water would lead to continuous drop of groundwater level,change of water quality and dry-up in dynamic water level observation wells.Due to land subsidence,the well pipes would uplift and the observation piping systems would be damaged.These environmental geology problems bring a great deal of difficulties to earthquake anomalies identification from groundwater level.Although a lot of studies have been made on the influence of water pumping on well water level,the results were mainly on the influence of massive water pumping in a short time on the water level of the nearby wells.Since the time of pumping water is short,the hydrogeological environment of aquifer is relatively stable.The characteristic of water level change in groundwater overdraft area is different from the influence of massive short-time water pumping on water level of the nearby wells.Since the water level in the overexploiting area declines year by year,it makes the aquifer dense and consolidated,so consequently,the hydrogeological environment has changed.Basing on the hydrogeological theories and methods,the paper analyzes the relations of hydraulic equilibrium state of water-bearing stratum with the stress-strain condition and the water level regime,then discusses preliminarily the theory and practices of identifying the well water level anomalies in the groundwater overdraft area.The result shows that we can accurately judge the nature of the anomaly according to the diffusion character of water level declining funnel in the well area,the aforementioned theory and method and the multi-years variation pattern obtained from existing data.The results of the research are helpful to the discrimination of influence of the individually centralized water pumping from long-term overexploiting of water on the water level,the correct recognition of water level anomalies in the groundwater overdraft area and the improvement of earthquake prediction level.

Key words: groundwater overexploitation, water level observation, anomaly recognition

摘要： 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。

关键词: 地下水超采, 水位观测, 异常识别