2008年汶川地震破裂向东北传播的应力作用证据

基于采用混合大地测量数据反演得到的破裂分布模型，从库仑应力的角度计算北川断层的破裂过程，为北川断层从西南向东北破裂提供应力作用上的证据。将北川断层分为5个断层，分别计算前续断层在后续断层上产生的库仑应力变化。结果显示：1）映秀-虹口段在龙门山-清平段上、龙门山-清平段在高川-北川段上、高川-北川段在北川-屏东段上和北川-屏东段在南坝-青川段上产生的库仑应力变化为正的区域占绝大部分；2）高川-北川段上有约81.7%的区域破裂主要是由龙门山-清平段的破裂触发，而前续断层（映秀-虹口段）对高川-北川段上的破裂影响很小；3）北川-屏东段上有约83.2%的区域破裂主要是由高川-北川段的破裂触发，而前续断层（映秀-虹口段和龙门山-清平段）对北川-屏东段上的破裂影响很小；4）南坝-青川段上有约99.4%的区域破裂主要是由北川-屏东段的破裂触发，而前续断层（映秀-虹口段、龙门山-清平段和高川-北川段）对北川-屏东段上的破裂影响很小。同时，计算北川断层对彭灌断裂的应力触发作用，推测映秀-虹口段的破裂触发了彭灌断裂上大部分区域的破裂，龙门山-清平段的破裂触发了彭灌断裂上一小部分区域的破裂。

Evidence on the Stress Effect of the 2008 Wenchuan Earthquake Rupture to the Northeast

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.