• 责任者：Wang Changzai (Institute of Geophysics ; China Earthquake Administration ; Beijing 100081 ; China) ; Wu Jianping
• 刊名：Chinese Journal of Geophysics
• 出版年：2013
• 卷期：56(12)
• 关键词：玉树地震2010 ; Yushu earthquake 2010 ; 余震 ; aftershocks ; 速度结构 ; velocity structure ; 青海 ; Qinghai Province
• 页码：p.4072-4083
• 图表：8 illus., 1 table, 38 refs.
• 分类号：0500
• issnNo：ISSN0001-5733
• isbnNo：CN11-2074/P

     Using travel time data from 21 temporary seismic stations and the permanent stations of Qinghai Seismological Network, we obtained precise relocation of earthquake sequence and 3D seismic velocity structure around Yushu focal area by double-difference tomography. To ensure the accuracy of the phases, the seismic events downloaded from the Data Management Center of China National Seismic Network were re-processed. The result of aftershock relocation shows that the earthquake sequence has a banding distribution along NW in both sides of the fault, which reveals horizontal lineations of hypocenters that define the narrow regions on the fault where stress is released by brittle failure. At the northwest end the aftershocks are distributed not only along the Yushu-Garzfi fault, but also along the direction vertical to the fault. It reveals an intersecting fault. The result of 3D seismic velocity structure showed that shallow velocity structure has good correlation with surface geology. The velocity structure of middle crust shows that Bayan Har block is characterized by high velocity, Qiangtang block is imaged as a lowvelocity region. The result of earthquake location and seismic velocity structure shows that the high-low velocity anomaly has certain control action to the aftershock distribution. The mainshock occurred in the transition zone between low and high velocity bodies. Most aftershocks appear to be distributed on the periphery of the high-velocity body. There are rarely earthquakes in the high-velocity body. The high-velocity body rdlects the more brittle and competent parts of the crust, which are capable of sustaining greater seismogenic energy. The seismogenic energy in the high-velocity body was released into the surroundings after the mainshock, which leads to many aftershocks in the surrounding areas.