触发多断层面破裂的2022年四川马尔康M_(s)6.0震群特征  

Characteristics of the Ma’erkang M_(S)6.0 Earthquake-Swarm Triggered along Multiple Fault Planes in 2022

作　　者：杜方[1] 龙锋[1] 梁明剑[1] 祁玉萍[1] 宫悦[1] 吴江[1] DU Fang;LONG Feng;LIANG Mingjian;QI Yuping;GONG Yue;WU Jiang(Sichuan Earthquake Agency,Sichuan Chengdu 610041,China)

机构地区：[1]四川省地震局,四川成都610041

出　　处：《四川地震》2022年第4期1-10,共10页Earthquake Research in Sichuan

基　　金：国家重点研究计划(2021YFC3000702-05);西藏拉萨地球物理国家野外科学观测站研究课题(NORSLS21-04);地震动力学国家重点实验室开放基金课题(LED2020B02)共同资助.

摘　　要：2022年6月10日在四川省阿坝藏族羌族自治州马尔康市接连发生M_(s)5.8、M_(s)6.0和M_(s)5.2地震。依据2022年四川马尔康M_(s)6.0震群序列资料,采用多阶段定位方法对震群序列进行重定位,并结合震源机制解和区域构造开展了震群序列的时空特征研究。结果显示:马尔康M_(s)6.0震群属多断层面触发性震群,震源集中在地壳15 km以上浅部,发生在巴颜喀拉Ⅱ级活动地块内,展布于NW走向的松岗断裂及其两分支断层的北东侧;M_(s)5.8和M_(s)6.0地震为松岗断裂北东侧的NNW走向的F_(A)断层和F_(B)断层的左旋走滑的破裂事件,M_(s)5.2地震为与龙日坝断裂有“牵连”的NE走向的F_(C)断层的右旋走滑的破裂事件。同时,获得震后趋势快速研判的几点启示:多断层面触发性震群的快速趋势研判需重视小区域内断裂的发震能力、序列分布迁移、序列频次和强度衰减的跟踪研判;序列趋势快速研判需将震群“序列”放入“发震构造环境”和“历史破裂事件”中进行综合认识。The M_(s)5.8,M_(s) 6.0 and M_(s) 5.2 Ma'erkang earthquakes occurred in Aba Tibetan and Qiang Prefecture,Sichuan on June 10,2022.Based on the sequence data of the M_(s) 6.0 earthquake-swarm that occurred in 2022,the temporal and spatial characteristics of the earthquake-swarm sequence were studied in this paper.We used precise positioning of the earthquake-swarm sequence,combined with the results of the focal mechanism solution and regional tectonic data.The results show:The M_(s)6.0 Ma'erkang earthquake-swarm belongs to the earthquake-swarm triggered by multiple fault planes.The M_(s) 60 Ma'erkang earthquake-swarm occurred in the Bayan Har active Block of level II,and spreads on the northwest side of the NW-trending Songgang fault and the two branches of the Songgang fault-Songgang fault 1 and 2 branches.The M_(s)5.8 and M_(s)6.0 earthquakes are the rupture events of the left-lateral strike-slip of the NNW-trending F_(A)-and F_(B)-faults on the northwest side of the Songgang fault.The M_(s)5.2 is the rupture event of the right-lateral strike-slip of the NE-trending F-fault,which may be“implicated”with the Longriba fault.The hypocenter of the M_(s)6.0 Ma'erkang earthquake-swarm are concentrated in the shallow part above 15 km.At the same time,several inspirations for obtaining the rapid research and judgment of post-earthquake trends are included:In the rapid trend study of the earthquake-swarms triggered by multiple fault planes,the tracking and judgment of fault seismogenic capacity,sequence distribution migration,sequence frequency and intensity in small areas all need to be focused.In the rapid study of sequence trends,ii is necessary to pay attention to the understanding that the earthquake-swarm“sequence”is placed in the“sesmogenctectoncenvronment”and“hstorcalruptureevents”.

关 键 词：四川马尔康M_(s)6.0震群 多断层面触发性震群 松岗断裂 龙日坝断裂 左旋走滑 右旋走滑 

分 类 号：P315.7[天文地球—地震学]