玉树地震产生的位移场和应力场研究

根据2010年4月14日玉树7.1级地震的震源破裂模型及余震目录, 本文计算了玉树地震产生的位移场和库仑破裂应力。 计算结果表明, 玉树地震导致应力变化以破裂带为中心高达正负1000Pa变化, 沿近东西方向应力增加, 巴彦喀喇山主峰断裂、 清水河断裂、 杂孕—楚玛尔河断裂东南段、 称多—曲麻莱—五道梁断裂、 冶多断裂中段, 扎那曲—着晓断裂、 莫云—结多断裂、 杂多—上拉秀断裂西北段处于应力增强区, 冶多断裂中段、 杂多—上拉秀断裂应力增强尤为显著, 高达1000 Pa之多, 应力的增加有利于这些断裂活动性增强。 而沿破裂带方向的断层如甘孜—玉树—风火山断裂带及玉树南—风火山南麓断裂西北段应力减小, 对这些地区后续地震的发生有一定的抑制作用。

Study on the Displacement Field and Coulomb Failure Stress Generated by the 2010 Yushu Earthquake

Based on the rupture model of April 14,2010 Yushu M7.1 earthquake and its aftershock catalogue,we calculated the displacement field and Coulomb failure stress.The Yushu earthquake made significant changes to the regional seismic stress field.The calculation results show that: Yushu earthquake caused stress changes up to amount of positive and negative 1 000 Pa centered along the rupture zone;and along the nearly east-west direction stress increases.Bayan Kala mountain peak fracture,Qingshui River fracture,Zayun-Chu Kumar River fault southeast section,Chengduo-Qumalai-Wudaoliang fracture,and Zhiduo fracture′s middle section,Zanaqu-Zhaoxiao fracture,Moyun-Jieduo fracture,Zaduo-Shanglaxiu fracture′s northwest section in the area of stress increased.Zhiduo fracture′s middle section,Zaduo-Shanglaxiu fracture′s stress increase particularly strong,up to the amount of 100 Pa.While along with the direction of rupture fault such as Ganzi-Yushu-Fenhuosan fracture zone and the south of Yushu-south of Fenhuosan fracture zone′s northwest section stresses were reduce,which can inhibit certain following earthquakes in these areas.