关键词: 地下水超采, 水位观测, 异常识别

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