系统梳理2021年3月24日新疆拜城MS 5.4地震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地震活动：震前存在地震平静、高频、带状分布等异常；②地球物理观测：出现5项异常，其中形变3项，电磁2项，且形变异常对于该地震具有预测意义；③综合方法：地震发生前，震中附近存在多参数概率谱异常。拜城MS 5.4地震发生在库车坳陷西南部，震源机制解显示为走滑型破裂。该序列类型为前震—主震—余震型，主震前存在前震活动，余震较少，序列活动呈持续衰减特征。综合分析认为，拜城MS 5.4地震前异常较多，其中地震活动相关异常为后续中强地震的预测提供了有效依据。
An earthquake with the magnitude of MS 5.4 occurred in Baicheng County, Xinjiang Uygur Autonomous Region on March 24, 2021. The historical seismicity, geophysical observations before the mainshock and tectonic background are systematically summarized in this paper. The results show that:① Seismicity anomalies:seismic quiescence, high seismic frequency, belt-like seismic distribution, and other seismicity anomalies emerged before the occurrence of the Baicheng MS 5.4 earthquake;② Geophysical observations:there are 5 geophysical anomalies of which 3 anomalies relate to deformations and 2 anomalies are electromagnetic;③ The comprehensive method demonstrates that there is an abnormal in probability spectrum of multi-parameter before the Baicheng MS 5.4 earthquake. The Baicheng MS 5.4 earthquake occurred in Kupa Depression, and the focal mechanism of the mainshock is strike-slip faulting. The seismic activity of the Baicheng MS 5.4 earthquake sequence indicates that there is a foreshock before the mainshock. Thus, the Baicheng MS 5.4 earthquake sequence is a foreshock-mainshock-aftershock sequence. Moreover, there are few aftershocks and the current daily cumulative rate of the sequence shows an attenuation trend. The systematical analysis of the Baicheng MS 5.4 earthquake indicates that plenty of anomalies emerged before the Baicheng MS 5.4 earthquake in which seismicity anomalies provided efficient clues for subsequent earthquakes.
2021,42(3): 250-263 收稿日期：2021-05-10
DOI：10.3969/j.issn.1003-3246.2021.03.031
基金项目：中国地震台网中心青年科技基金“强震危险地点预测方法研究——以南北地震带为例”；国家重点研发计划（项目编号：2018YFC150330502）
作者简介：解孟雨(1991-),男,博士,工程师,从事地震预报研究工作。E-mail:xiemengyu@seis.ac.cn
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