2021年5月22日青海玛多M_(S)7.4地震总结

Summary of Maduo M_(S)7.4 earthquake in Qinghai on May 22,2021

系统梳理2021年5月22日青海玛多M_(S)7.4地震发生前地震活动异常特征、地球物理观测异常以及区域构造情况,结果如下:①玛多M_(S)7.4地震发生在巴颜喀拉块体内部,发震断层应为昆仑山口—江错断裂;②地震发生前存在地震平静、带状分布等地震活动异常;③存在形变、电磁和流体异常,其中流体异常对于该地震具有一定的短期预测意义。玛多M_(S)7.4地震序列类型为主震—余震型,余震较为丰富,序列持续衰减特征明显。综合分析认为,玛多地震前存在多种地震活动和地球物理观测异常,其中流体异常为本次地震的时间和地点预测提供了有效依据。

An earthquake with the magnitude of M_(S)7.4 occurred in Maduo County,Qinghai Province on May 22,2021.The historical seismicity,geophysical observations before the mainshock and tectonic background are systematically summarized in this paper.The results show that:(1)The Maduo M_(S)7.4 earthquake occurred in Bayankala block,and the seismogenic fault of this earthquake is the Kunlun Pass-Jiangcuo fault;(2)Seismic quiescence,earthquake gap,beltlike seismic distribution,and other seismicity anomalies emerged before the occurrence of the Maduo M_(S)7.4 earthquake;(3)There are geophysical anomalies before the Maduo M_(S)7.4 earthquake which contains anomalies relate to deformations,electromagnetic anomalies,and fuid anomalies,in which fuid anomalies show certain short-term prediction signifcance for the earthquake.The seismic activity of the Maduo M_(S)7.4 earthquake sequence indicates that the Maduo M_(S)7.4 earthquake sequence is a mainshock–aftershock sequence.Moreover,there are plenty of aftershocks and the current daily cumulative rate of the sequence shows an attenuation trend.The systematical analysis of the Maduo M_(S)7.4 earthquake indicates that various seismic and geophysical anomalies emerged before the Maduo M_(S)7.4 earthquake in which fuid anomalies provided effcient clues for forecasting the time and location of the subsequent earthquakes.