利用国家测震台网观测资料,对2022年1月8日青海门源6.9级地震震中距200km以内的19个台站自2021年记录到的临震微波动事件进行分析,发现震中距103km的祁连台在震前3个月存在显著异常,临震微波动事件的活动度(N值)高达20; 震中距158km的拉脊山台同样出现活动度高值异常,达到异常指标; 震中124km的湟源台长期处于异常状态,但在震前3～4个月表现为明显高于背景值的高值异常。其他台站虽然未达到异常指标,但震前3个多月活跃天数显著增加。异常显著的台站与震中位置呈线性分布,震中NW—SE方向的台站记录的事件更显著; 本次地震前的微波动现象与2021年玛多7.4级地震前的微波动现象存在共同特征,可能与两次地震相似的震源机制解有关。

Based on the observation data of national seismological network,we analyze the impending dynamic signals of micro earthquake events recorded within 200km radius of the Menyuan M6.9 earthquake on January 8,2022,Qinghai Province,and we find that a significant anomaly has been detected at the Qilian station,and the activity value(N value)is up to 20. The earthquake occurs 3 months later after the end of the anomaly. A single anomaly index was found once at the Lajishan station reaches the,Whereases Huangyuan station with the epicenter of 124km was in an abnormal state for a long time,with a high value anomaly obviously higher than the background value 3～4 months before the earthquake. Although other stations did not reach the anomaly index,the number of active days increased significantly more than 3 months before the earthquake. The stations in the southeast and northwest of the epicenter have more phenomenon of impending micro events motion than those in the north. The characteristics of events motion before this earthquake have something in common with the Maduo M7.4 earthquake in 2021. It may be due to the similar focal mechanism solutions of the two earthquakes.

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国家重点研发计划项目(2021YFC3000705-04)、甘肃省科技重大专项(21ZD4FA011)、甘肃省地震局地震科技发展基金(2022Q201)和甘肃省地震局创新团队(2019TD-02-01)共同资助