Title: Research and prospect of seismicity in southern segment of longmenshan fault zone
Venue: 4F Lecture Hall
Speaker: Prof. Liang Chuntao (Chengdu University of Technology)
Time: August, 23, 2019 10:00 AM
Summary of report:
After the Wenchuan and Lushan earthquakes, the southern section of Longmenshan fault zone has an unruptured section of about 40-60km, which is called the seismic void zone. In order to study the seismicity of the seismic void, the research team set up more than 70 temporary seismic stations in the zone, and obtained the spatial and temporal distribution of micro quakes of magnitude Mc= 0. It was found that there was a significant negative correlation between the number of micro quakes and rainfall. And the distribution of micro seismic b value has significant spatial variation. There is a significant positive correlation between the spatial distribution of micro earthquakes and the basement extensional zone with high strength in the middle and lower crust of Sichuan basin. The genetic model of the seismic void zone is proposed: due to the horizontal stress difference parallel to the fault, the extensional zone westward of the Sichuan basin basement is damaged and torn in the void zone, and partial melting occurs in the middle and lower crust. However, the Qianshan fault and the Dayi fault in the basin are located on the basement of the Sichuan basin, in the elastic strain zone, with active micro seismic activity and low B value, and the possibility of large earthquakes.
Institute of Geodesy and Geophysics. Chinese Academy of Sciences
Address:340 XuDong Rd. Wuhan 430077, Hubei, China