[1]WU Weiwei,LIANG Mingjian,LONG Feng,et al.Analysis of the Present-day Activity of the Qingchuan Fault and Its Vicinity[J].Journal of Seismological Research,2023,46(02):188-203.[doi:10.20015/j.cnki.ISSN1000-0666.2023.0035
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Analysis of the Present-day Activity of the Qingchuan Fault and Its Vicinity
Journal of Seismological Research[ISSN 1000-0666/CN 53-1062/P] Volume:
46
Number of periods:
2023 02
Page number:
188-203
Column:
Public date:
2023-03-10
- Title:
- Analysis of the Present-day Activity of the Qingchuan Fault and Its Vicinity
- Keywords:
- the Qingchuan fault and its vicinity; the Wenchuan MS8.0 earthquake; focal mechanism; stress drop; velocity structure; earthquake activity
- CLC:
- DOI:
- 10.20015/j.cnki.ISSN1000-0666.2023.0035
- Abstract:
- In recent years,earthquakes(M≥4.0)have been repeatedly occurring on the Qingchuan fault and in its adjacent region. Firstly,we conduct a geological investigation and carry out a surveying and mapping of landforms area by the unmanned aviation vehicle in the study in order to obtain the tectonic deformation of the Qingchuan fault. Secondly,we use the cut-and-paste method to invert the focal mechanisms of 32 earthquakes(MW≥4.0)occurring during May 17-December 31,2008 in the study area,and further study the tectonic features of the Qingchuan fault. Thirdly,we use the ω2 model to fit the source spectra to obtain the dynamic evolution of the stress drop in 10-year span in the study area. Then we analyze the stress variation before and after the 2008 Wenchuan earthquake,the 2013 Lushan earthquake,the 2017 Jiuzhaigou earthquake. Fourthly,we invert the P-wave velocity structure in the study area to discuss the tectonic settings for the earthquake genesis in the deep. Finally,on the basis of the above the geological and seismological results we analyze the resent-day activity of the Qingchuan fault. We find that:①The geological survey and the focal mechanism solution show that movement property of the Qingchuan fault is mainly strike-slip,with a certain compressive component. ②Before and after the 2008 Wenchuan earthquake and the 2013 Lushan earthquake,the stress in the study area experienced a rise-fall period. ③Spatially,the body-wave tomography shows that the high-speed anomaly and low-speed anomaly in the shallow Crust are divided by the Longmenshan fault. ④The Qingchuan fault is an earthquake-prone structure because of its tectonic settings. So far,the strong-earthquake activity is in the weakening period; the seismicity(M≥4.0)takes on a trend of gradual attenuation. High stress-drop events are significantly lessening and the overall stress level in the study area is relatively low.
- References:
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Last Update:
2023-03-10