2021年青海玛多7.4级地震前地震活动异常特征分析

结合青海玛多7.4级地震前日常跟踪工作中出现的地震活动异常,系统梳理羌塘块体6级地震成组、中国大陆5级地震低频活动、青藏高原东北缘中等地震活动显著增强以及青藏高原东北缘地区震群活动的时空异常特征,总结多项指标的预测意义,并对部分重要指标做了预测效能评估。同时,通过研究碌曲震群的时空分布特征,认为碌曲地区是一个应力敏感区域,对周边地区中强地震的发生有较好的预测意义,在后续震情监视过程中应该作为重要指标来跟踪。

Characteristics of seismicity anomalies before the 2021 MaduoM7.4 earthquake in Qinghai Province

Combined with the seismicity anomalies recorded in the daily tracking word before the Maduo M7.4 earthquake, we systematically sorted out the characteristics of grouping activities of M6 earthquakes in the Qiangtang Block, the low-frequency activities of M5 earthquakes in mainland China, the significant enhancement of moderate seismic activities in the northeastern Tibetan Plateau, and the temporal and spatial anomalies of the seismic swarm activities in the northeastern Tibetan Plateau. We not only summed up the prediction significance of several indexes, but also evaluated the prediction efficiency of some important indexes. Meanwhile, through the temporal and spatial distribution characteristics of Luqu earthquake swarm, we concluded that the Luqu area is a stress-sensitive area; the Luqu earthquake swarm has a good prediction significance for the occurrence of moderate and strong earthquakes in the surrounding area, and should be used as an important index in the subsequent earthquake monitoring process.