We use the 2010-2012 gravity data from the Ningxia survey network,recalculated by a one degree term of scale parameter of the CG-5 gravimeter.We conduct a comparative analysis of the impact of correction coefficient term grid values at different time scales produced by the gravitational field before the Yinchuan ML5.0 earthquake.Our results show:(1) CG-5 gravimeter one degree scale parameter decreases with time,and continuesa declining trend;(2) different time scale gravity field changes are significantly reduced,highlighting the "0" contour phenomenon.%使用宁夏测网2010~2012年流动重力观测数据,利用重力差方法重新计算得到CG5重力仪的一次项格值系数,对比分析2012年银川ML5.0地震前,修正前后一次项格值系数对不同时间尺度重力场所产生的影响.结果表明:1)CG-5重力仪一次项格值系数随时间逐渐减小,呈持续下降的变化趋势;2)一次项格值系数修正前后不同时间尺度重力场变化量均明显减弱,凸显了“0”等值线现象.
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