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对前郭M_S5.8地震后6个月(2013年10月31日~2014年4月30日)内的地震事件进行了重新定位,并利用吉林区域地震台网提供的地震目录研究了序列活动特征。精定位结果显示,余震区呈NW走向分布,长轴约11km,短轴约6km。震源深度为5~15km。结合区域构造特征认为,该序列可能与NW走向的通榆-长春隐伏断裂活动有关,序列具有b值较低、5级地震频次高、发震时间集中的特点。序列主要起伏活动可以分为3个时段:主震后10天,余震强度衰减不明显;此后的2次起伏活动,地震活动分别表现出平静-增强(震级爬升)-发生强震和增强(震级爬升)-平静-再增强(震级爬升)-发生强震的特点;在序列早期阶段,震级-频度无法拟合成1条直线,G-R关系在低震级段和高震级段呈现2个线性段;在M_S5.8地震前h值有变小的趋势,且接近1;而M_S5.8地震后h值明显增大;M_S5.5地震后15天序列衰减比较慢,p值为0.76;M_S5.8地震后15天序列衰减较快,p值为1.17。
The seismic events within 6 months after the Qian Guo M_S5.8 earthquake (October 31, 2013 ~ April 30, 2014) were repositioned and the sequence activities were studied using the earthquake catalog provided by Jilin Seismic Network feature. The fine positioning results show that the aftershock zone presents a NW distribution with a long axis of about 11km and a short axis of about 6km. The focal depth is 5 ~ 15km. According to the regional tectonic characteristics, this sequence may be related to the NW-trending Tongyu-Changchun concealment fault. The sequence has the characteristics of lower b value, higher earthquakes of magnitude 5 and greater time of occurrence of seismogenic events. The main ups and downs of the sequence can be divided into three periods: aftershock intensity decay is not obvious at 10 days after the main shock; after that, the second undulation activity and seismicity respectively show calm-enhanced (magnitude climb) Climbing) - Calm - Reinforced (Magnitude Climb) - Features of strong earthquakes; Magnitude-frequency can not be fitted to a straight line in the early stages of the sequence, GR relations show two linear segments at low and high magnitudes ; The value of h before the M_S5.8 earthquake tends to decrease, which is close to 1; while the value of h after M_S5.8 earthquake increases obviously; the sequence of 15 days after M_S5.5 earthquake decays slowly, with a p value of 0.76; M_S5. The 15-day sequence attenuated rapidly after the 8th earthquake with a p-value of 1.17.