Abstract:Based on fracture distribution model, which uses a mixed inversion of geodetic data, this study calculates the rupture process of the Beichuan fault from the perspective of the Coulomb stress calculation. The results of this paper offer evidence on stress of the rupture of the Beichuan fault from southwest to northeast. The Beichuan fault is divided into five faults in this paper, and the Coulomb stress changes on the subsequent fault are calculated respectively. The results show that: 1) The Coulomb stress produced by Yingxiu-Hongkou section in most areas of Longmenshan-Qingping section is positive. The same is true for other segments, such as Longmenshan-Qingping section in Gaochuan-Beichuan section, Gaochuan-Beichuan section in Beichuan-Pingdong section and Beichuan-Pingdong section in the Nanba-Qingchuan section. 2) The rupture of the 81.7% area in the Gaochuan-Beichuan section was triggered by the rupture of the Longmenshan-Qingping section. However, the previous continuous fault(Yingxiu-Hongkou section) had little effect on the rupture of Gaochuan-Beichuan section. 3) the rupture of the 83.2% area of Beichuan-Pingdong section was triggered mainly by the rupture of the Gaochuan-Beichuan section. The previous continuous fault(Yingxiu-Hongkou section and Longmenshan-Qingping section) had little effect on the rupture of Beichuan-Pingdong section. 4) The rupture of 99.4% of the area in the Nanba-Qingchuan section was mainly triggered by the rupture of Beichuan-Pingdong section. The previous continuous fault(Yingxiu-Hongkou section, Longmenshan-Qingping section and Gaochuan-Beichuan section) had little effect on the rupture of Beichuan-Pingdong section. This paper also calculates the stress triggering effect of Beichuan fault on Pengguan fracture. We speculate that the rupture of Yingxiu-Hongkou section triggered the rupture of most areas of Pengguan fault, and the rupture of Longmenshan-Qingping section triggered the rupture of a small part of the Pengguan fault.
JIN Zhitong,WAN Yongge,WANG Fuchang et al. Evidence on the Stress Effect of the 2008 Wenchuan Earthquake Rupture to the Northeast[J]. jgg, 2019, 39(8): 783-789.