玉树地震地表破裂与宏观震中

2010年4月14日07时49分40.7秒, 青海省玉树藏族自治州玉树县发生M_S7.1级地震。通过现场调查发现, 玉树地震形成了东西两条地表破裂带——玉树地表破裂带和隆宝滩地表破裂带, 分别沿玉树活动断裂、隆宝滩活动断裂的上盘发育, 两条地表破裂带均呈NW向延伸, 二者之间相距22km。隆宝滩地表破裂带, 总体走向290°, 长21.5km, 呈左旋走滑运动, 左旋走滑位移量约1m。玉树地表破裂带, 总体走向310°, 长度23km, 可进一步分为三段。西段和中段表现为左旋走滑, 东段表现为左旋走滑逆冲运动。最大左旋走滑位移量在郭央烟宋多附近, 达2.4m。根据地震地表破裂的位移量大小和建筑物破坏情况认为, 玉树地震宏观震中在郭央烟宋多附近, 宏观震中坐标为:北纬33°03′11″、东经96°51′26″。 

THE SURFACE RUPTURES AND THE MACROSCOPICAL EPICENTER OF YUSHU MS7.1 EARTHQUAKE

At 7： 49： 40.7 on April 14,2010,a MS 7.1 earthquake happened in Yushu County of Qinghai Province.In the field investigation two surface rupture zones were observed from west to east,Longbaotan surface rupture zone and Yushu surface rupture zone.They display NW trending and are respectively developed along hang wall of the Longbaotan active fault and Yushu active fault at an interval of 22km.The Longbaotan surface rupture zone,trending along 290° with a length of 21.5km,was sinistral strike-slip movement with a sinistral strike-slip displacement of about 1m.The Yushu surface rupture zone,trending 310° with a length of 23km,can be further divided into three sections.It shows sinistral strike-slip movement in western and middle segment,sinistral strike-slip and thrust in eastern segment.The maximum sinistral strike-slip displacement（2.4m） of the rupture zones appears near the Guoyangyansongduo.According to the displacement of the earthquake surface rupture and building destruction,the earthquake macroscopical epicenter can be considered in the Guoyangyansongduo near the macroscopical epicenter coordinates： at 33°03′11″N and 96°51′26″E.