图36  共和7.0级地震前长宁水氡异常曲线

     （a）月均值及其校正值；（b）日测值指数窗速率

Fig. 36  Curves of radon amomalies in groundwater before  

         the M7.0 Gonghe earthquake at Changning station

       （a）Monthly mean value and its corrected value；

       （b）Velocity curve of daily observation exponential window