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根据著名的Ｇｕｔｅｎｂｅｒｇ－Ｒｉｃｈｔｅｒ（以下简写成Ｇ－Ｒ）地震频次－震级统计关系式研究了我国东部地区（１０８°Ｅ以东）部分Ｍｓ≥５．０中强地震前一定时空尺度内中小地震频次与震级线性拟合优度（线性相关系数ｒ）随时间变化的特征。结果表明，利用中强地震前震中区一定范围内的中小地震进行Ｇ－Ｒ关系式拟合时，其线性拟合优度在地震前出现不同程度的异常现象。其变化特点是：在中强地震发生前期，震源区及其附近中小地震的发生在能级上分配均匀，线性拟合优度接近１；随着中强地震的临近，该区中小地震在能级上的分配存在着较显著的不均匀现象，表现为线性拟合优度明显下降。这种拟合优度的异常变化具有中期异常性质，有可能为中强地震的中期判定提供依据。
Based on the frequency-magnitude statistical relationship of the famous Gutenberg-Richter (G-R) earthquake, we study the frequency of small to medium earthquakes within a certain space-time scale before the moderate earthquakes of Ms≥5.0 in the east of China (east of 108◦E) And linearity goodness of fit (linear correlation coefficient r) with time. The results show that when the G-R relationship is fitted by means of medium and small earthquakes within a certain range of the epicentral region before the strong earthquakes, the linear goodness of fit shows different degrees of anomalies before the earthquake. The characteristics of this change are as follows: During the early period of moderate-strong earthquakes, the occurrence of small-medium earthquakes in and around the source area and its vicinity are evenly distributed on the energy level and the linear goodness-of-fit is close to 1. With the approaching of the moderately strong earthquakes, There is a significant non-uniform distribution of the level, showing a significant decline in the linear fit goodness. The anomalous variation of this goodness of fit has the mid-term anomaly, which may provide the basis for mid-term judgment of moderately strong earthquakes.