• ISSN 2097-1893
  • CN 10-1855/P

2022年9月5日四川泸定MS6.8地震余震序列重定位研究

Aftershock sequence relocation of the MS6.8 earthquake on September 5, 2022, in Luding, Sichuan Province

  • 摘要: 2022年9月5日四川甘孜州泸定县发生MS6.8地震,极震区烈度达IX度,造成了严重的人员伤亡和经济损失. 本文首先通过HypoDD对主震及其震后25天内的余震序列进行了重定位,得到了精确的震源位置及空间分布,给出了主震的震中位置和深度,分别为(29.59°N,102.10°E)和14.3 km. 其次,通过对泸定MS6.8地震余震时空分布和震源深度剖面的分析,得到余震区的破裂长度约为65 km、宽度约为10~20 km,余震区发育了北段、中段和南段3个震群,震源深度从北段至南段逐渐加深;进一步分析了地震的发震构造,结果表明此次地震的主震及其余震分布在鲜水河断裂带的单侧,发震断层为鲜水河断裂带磨西段,同时触发了一条次级隐伏贡嘎山断裂. 最后,阐述了本次泸定MS6.8地震与2022年芦山MS6.1、2013年芦山MS7.0地震以及2014年康定MS6.3地震之间的孕震关系,并基于IDS系统反演了本次地震的震源运动过程,得到了主震破裂的基本参数,认为主震的破裂过程与余震的空间分布有较好的相关性.

     

    Abstract: On September 5, 2022, an MS6.8 earthquake, with a meizoseismal intensity of IX, struck Luding, Sichuan Province, causing severe casualties and economic losses. In this study, we applied the double-difference algorithm (HypoDD) to relocate the mainshock and aftershock sequences within a 25-day period. Precise hypocentral and spatial distributions were determined, with the hypocentral location of the mainshock recorded at (29.59°N, 102.10°E) and a depth of 14.3 km. By analyzing the spatial and temporal distribution of aftershocks and the depth profile of the Luding MS6.8 earthquake, we estimate that the aftershock fracture zone spans approximately 65 km long and 10–20 km wide. Three distinct aftershock clusters formed along the northern, central, and southern sections of the fault, with focal depths gradually deepening from north to south. Further analysis of the seismic structure revealed that the mainshock and aftershocks were distributed unilaterally along the Xianshuihe fault, specifically along the Moxi segment. This earthquake also activated a secondary, previously hidden fault near Gongga Mountain. Additionally, we examined the seismogenic relationships between the MS6.8 Luding earthquake and other recent seismic events, including the 2022 MS6.1 Lushan earthquake, the 2013 MS7.0 Lushan earthquake, and the 2014 MS6.3 Kangding earthquake. Using the IDS system, we inverted the hypocentral movement characteristics and obtained the basic parameters of the mainshock rupture, finding a strong correlation between the rupture process and the spatial distribution of aftershocks.

     

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