【摘要】 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。更多还原

【Abstract】 Our country has established an improved seismic underground fluid observation network.Underground water level is an important earthquake precursor factor and is applied to prediction measures.The observation data of groundwater level is an integrated parameter and includes many components determined by such factors as precipitation,atmospheric pressure,Earth tide,and geological structures.To highlight the influence of tectonic forces on groundwater level and to recognize the earthquake precursor information obtained by this parameters must be separated from original observation data.Components influenced by Earth tide and atmospheric pressure can be separated on the basis of a widely used theory.The influence of climate conditions on underground water level at a watershed scale,changes of which are long-term and periodic,can be separated through smooth processing methods.On the contrary,rainfall peaks influence underground water level,which reduces the effects created by structure forces;therefore,the identification of earthquake precursor information is difficult.In order to highlight tectonic forces on groundwater level,it is necessary to separate the peak value of rainfall effects on underground water level. In our study,we regarded the observation data of groundwater level as a linear combination of all of the components.Changes caused by Earth tide and atmospheric pressure were first separated according to the BAYTAP-G procedure.Then,because quick and slow response existed in the influence of rainfall on groundwater level,these effects were distinguished by applying base flow separation methods.Changes induced by rainfall were separated from groundwater level by using base flow separation methods.By analyzing the relationships between the curve feature of every component and local seismic activities,local earthquake precursor information on groundwater level could be recognized.In this study,we selected as research objects two observation wells including the Deyang Well in Sichuan,one of China’s earthquake underground fluid observation networks,the and Tuanjie-1 Well,one of the earthquake underground fluid dynamic monitoring networks located downstream of the Jinshajiang River.Based on the data of underground water level and pressure from the Deyang Well from April 1 to June 30,2008,we analyzed the changes in curves before and after the M8.0 Wenchuan earthquake that occurred on May 12,2008.On the basis of synchronous observation data of underground water level,rainfall,and pressure of the Tuanjie-1 Well from December 1,2010,to December 31,2011,we analyzed the effects of rainfall on water level. Results show that methods that regarded the underground water level as a linear combination of various factors and separated types of effect value from the original data were effective in practice.In addition,base flow separation methods were effective in reducing peaks of the rainfall influence on underground water level.Thus,earthquake precursor information can be identified more effectively.Once significant change occurs,whether such change is induced by earthquake activities needs to be considered.Through systematic research of a large number of typical earthquake examples,a regional earthquake precursor change model can be created,which can be used for earthquake prediction.更多还原