[1]ZHANG Zhiwei,ZENG Xianwei,WANG Di,et al.Study on the Stress State before the 2022,Lushan,Sichuan MS6.1 Earthquake[J].Journal of Seismological Research,2024,47(04):483-492.[doi:10.20015/j.cnki.ISSN1000-0666.2024.0061
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Study on the Stress State before the 2022,Lushan,Sichuan MS6.1 Earthquake
Journal of Seismological Research[ISSN 1000-0666/CN 53-1062/P] Volume:
47
Number of periods:
2024 04
Page number:
483-492
Column:
Public date:
2024-08-20
- Title:
- Study on the Stress State before the 2022,Lushan,Sichuan MS6.1 Earthquake
- Keywords:
- the Lushan MS6.1 earthquake; the Lushan MS7.0 earthquake; focal mechanism solution; stress tensor variance; b value; stress state
- CLC:
- P315.72
- DOI:
- 10.20015/j.cnki.ISSN1000-0666.2024.0061
- Abstract:
- On June 1,2022,an MS6.1 earthquake struck Lushan Country,Ya'an City of Sichuan Province.The earthquake is another significant event that occurred in the aftershock zone of the Lushan MS7.0 earthquake on May 20,2013.To figure out the genesis and occurrence of the Lushan MS6.1 earthquake,the CAP inversion method is used to calculate the focal mechanism of the Lushan MS7.0 mainshock and its MS≥5.0 aftershocks.And the mechanical mechanism and the stress state in the source area before the Lushan MS6.1 earthquake are discussed based on the spatial and temporal distribution of the stress tensor variance and b value.The main insights are as follows:The focal mechanism of the Lushan MS6.1 earthquake is featured as a thrust rupture,which is similar to the feature of the focal mechanism of the Lushan MS7.0 earthquake and its MS≥5.0 aftershocks.The direction of the principal compressive stress is consistent with the regional stress field of the southern section of the Longmenshan fault zone.The stress tensor variance and b value around the epicenter of the Lushan MS7.0 earthquake are in a low state in a long period.What is more,shortly before the Lushan MS6.1 earthquake,in its focal area there appeared low-value anomalies of the stress tensor variance and b value,indicating that the Lushan MS7.0 earthquake aftershock zone had been keeping a higher stress level.The continuous eastward movement of the Bayan Har block is blocked by the South China block.Thus,the aftershock zone of the Lushan MS7.0 earthquake is under the action of the horizontal extrusion and thrust,which leads to the long-term stress accumulation in this zone.Hence in this dynamic background,the Lushan MS6.1 earthquake occurred.
- References:
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Last Update:
2024-08-20