Present‐day Horizontal Motion and Deformation in the Northeast Part of the BarYan Har Block
详细信息
- 责任者：Chen Changyun (Institute of Geology ; CEA ; Beijing 100029 ; China) ; Ren Jinwei
- 刊名：Earthquake
- 出版年：2012
- 卷期：32(4)
- 关键词：构造变形 ; tectonic deformation ; 地壳运动 ; crustal movement ; 巴颜喀拉山 ; Bayan Har Mountains
- 页码：p.73-82
- 图表：4 illus., 33 refs.
- 分类号：0300
- issnNo：ISSN1000-3274
- isbnNo：CN11-1893/P
摘要
We have collected GPS data in the period of 2001—2009 from the Crustal Motion Observation Network of China in northwest of Sichuan,and the newest observation data from observed campaign stations which were built under the support of the National Key Basic Research Development Program,to study the characteristics of present-day crustal horizontal motion velocities in the research zone.Strain rate components are computed in spheric coordinate system.Analyses of the spatial distribution strain rate fileds derived from GPS measurements are carried out in contrast with seismological and geological results.Results show that the horizontal motion of the GPS stations are consistent with the clockwise rotation of the whole Tibetan Pleatau around the Eastern Himalayan syntaxis.From west to east and northeast,the velocity decreases obviously.The principal compression strain rates are apparently greater than principal extension strain rates,especially in Tazang fault,the eastern part of Dongkunlun fault and the middle part of the Longmenshan fault.The principal compress strain is obviously in the eastern segment of the Dongkunlun fault.Combining analysises with the data of earthquake geology and active tectonics,we suggest that the motion characteristics may be changed from west to east,in the west,the fault shows an obviously left lateral strike-slip,but in the eastern segment,it not only show a left lateral motion but also an compress movement.The motion characteristics of the boundary fault plays an important part in adjusting the relative motion with the blocks.Based on the velocity filed and strain filed from GPS data,we think that the motion in the reasearch zone can be thought as a block motion,most obvious deformation mainly on the boundary faults of the active blocks.