[1]LIU Changwei,CHANG Zufeng,WANG Guangming,et al.Fault Structure Characteristics of the Yangbi,Yunnan MS6.4 Earthquake in 2021[J].Journal of Seismological Research,2023,46(03):353-331.[doi:10.20015/j.cnki.ISSN1000-0666.2023.0038
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Fault Structure Characteristics of the Yangbi,Yunnan MS6.4 Earthquake in 2021
Journal of Seismological Research[ISSN 1000-0666/CN 53-1062/P] Volume:
46
Number of periods:
2023 03
Page number:
353-331
Column:
Public date:
2023-06-25
- Title:
- Fault Structure Characteristics of the Yangbi,Yunnan MS6.4 Earthquake in 2021
- Keywords:
- the Yangbi MS6.4 earthquake; earthquake disaster risk survey; the Caoping fault; seismogenic structure
- CLC:
- P315.22
- DOI:
- 10.20015/j.cnki.ISSN1000-0666.2023.0038
- Abstract:
- An MS6.4 earthquake occurred near Yangbi County,Bai Autonomous Prefecture of Dali,Yunnan Province on May 21,2021.The earthquake location is characterized by complex geological structures,and the epicenter is located in the Weixi-Qiaohou fault at the west edge of the Sichuan-Yunnan rhombic block.In order to investigate the risk of earthquake disasters and identify the characteristics of the fault structures in the region,a field survey was carried out on several fault structures,based on the 1:250 000 seismic structure mapping of Yangbi County.The results show that the Caoping fault has no significant activity since the Quaternary,and it does not have the tectonic conditions for above MS6.0 strong earthquakes independently; The regional tectonic evolution indicates that the Caoping fault was formed before the the Weixi-Qiaohou fault started to act,such a preexisting fault and the likes play an important role in regional stress release in the earthquake event.Under the condition of intense Holocene activity in the middle section of the Weixi-Qiaohou fault,the Yangbi MS6.4 earthquake was an event that ruptured along the tectonic plane of the preexisting fault.Relocation results show that the SE end of the seismic sequence has a geometric feature of bifurcation.We believe that the dextral shearing caused by the earthquake makes the later aftershock rupture inherit the geometric structure of the Lashi fault,the Xiaozhuang village fault and the Luojia village fault,and disperses and absorbs the residual stress.
- References:
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Last Update:
2023-06-25