中文摘要：

计算了2008年3月21日新疆于田Ms7．3地震导致周围断层的库仑破裂应力变化．结果表明，库仑应力在贡嘎错断裂的西南段和东北段、康西瓦断裂东段和西段、普鲁断裂西段、龙木错-邦达错西段、阿尔金断裂和西昆仑山前逆冲断裂增加分别达6．9×10^4 Pa、4．4×10^3 Pa、8．0×10^5 Pa、2．8×10^3Pa、2．3×10^4Pa、5．7×10^3Pa、1．6×10^3Pa和1．1×10^3Pa，而使得贡嘎错断裂中段、康西瓦断裂中段、龙木错-邦达错东段、普鲁断裂中段和喀喇昆仑北段断层上的库伦破裂应力减小分别达3．9×10^5 Pa、5．8×10^5Pa、1．5×10^4Pa、1．5×10^4Pa和1．1×10^3Pa．根据康西瓦的断层滑动速率估计该地震使得中段特征地震延迟1～127年，使得东段特征地震提前2～138年．计算还得到2005年10月8日巴基斯坦Mw7．6地震在于田地震破裂面和滑动方向上产生的库仑破裂应力增加为10～20Pa，虽然有利于于田地震的发生，但数值太小，难以看到明显的触发作用．分析了该地震及其周围已发生地震出现正断层机制的原因．认为在印度板块向欧亚板块北北东向推挤作用下，相对塔里木块体，青藏高原北缘的柴达木块体沿阿尔金断裂东向运动，而兴都库什块体沿喀喇昆仑断裂整体北西向运动．地震发生区位于此两块体之间，在双边动力相互作用下导致了东西向拉张的形变模式．

英文摘要：

Abstract We calculate the Coulomb failure stress changes caused by the 21 March 2008 M~7.3 Yutian, Xinjiang earthquake on its neighboring faults. The result shows that the Coulomb failure stresses increased along the southwest and northeast segments of the Gonggacuo fault, the east and west segment of the Kengxiwar faults, the west segment of the Pulu fault, the west segment of the Lungmu Co--Bangdag Co, the Ahyn Tagh fault and the western Kunlun thrust fault by 6.9X104 Pa, 4.4X10a Pa, 8.0X10s Pa, 2.8）〈10a Pa, 2.3X104 Pa, 5.7X10a Pa, 1.6X10a Pa and 1.1）〈10a Pa, respectively, decreased along the central segment of the Gonggacuo and Kengxiwar faults, the east segment of the Lungmu Co--Bangdag Co fault, the central segment of the Pulu fault, and the north segment of the Karakorum fault by 3.9 X 105 Pa, 5.8 ~ 105 Pa, 1.5 X 104 Pa, 1. 5 ）〈 104 Pa and 1. ] X 10a Pa, respectively. We estimated that the characteristic earthquake delayed 1~127 years in the central segment and advanced 2~138 years by the Yutian earthquake according to the slip rate on this fault. The Coulomb failure stress change caused by the 8 October 2005 Pakistan earthquake and projected on the fault plane and slip direction of the Yutian earthquake is 10~20 Pa, and is in favor of its occurrence. The Yutian earthquake has a normal faulting mechanism. Its origin is interpreted as the result of NNE intrusion of the India plate into Eurasia plate, causing with respect to the Tarim Block, the Qaidam Block in the northern part of Qinghai-Tibet Plateau move to the east along the Altyn Tagh Fault, and the Hindukushi Block move to the northwest along Karakorum Fault, respectively. The Yutian earthquake occurred between the Qaidam and Hindukushi Blocks, its east-west extension deformation pattern is resulted from the kinematic relative motion of the two blocks.