Abstract:Based on GPS horizontal velocity data from 1999-2007 and 2009-2013, mainly from the crustal motion observation network of China(COMMON), using the GPS velocity profiles, and combing with the principal strain rate field near the west Qinling fault, this paper analyzes the motion and deformation along different segments of the west Qinling fault. The results show that from 1999-2007, the characteristic of the whole fault is left strike slip with compression; among all four segments, the Guomatan has the highest activity, and the Tianshui-Baoji segment has the lowest. The principal strain rate along the whole west Qinling fault derived from GPS measurements shows that the principal compression strain rates are apparently greater than the principal strain rates. However, strain rate values are obviously different: the compression strain rate of the Guomatan and Yuanfeng segments are greater than the Zhangxian and Tianshui-Baoji segments. Compared to data from 1999-2007, the results during 2009-2013 show that the Zhangxian segment becomes more active, and has a relatively large tensile strain rate. These changes in the Zhangxian segment maybe caused by the Minxian-Zhangxian MS6.6 earthquake on July 22, 2013. The characteristics of principal strain rate of all segments of the west Qinling fault are the same as the results derived from the GPS velocity profiles. After comprehensive analysis of the remote and near field deformation characteristics acquired by the GPS velocity profiles and GPS principal strain rate field, we find that the whole west Qinling fault may be in a locked state, showing strain accumulation to a certain extent; among the four segments, the Tianshui-Baoji segment has the lowest activity, and this feature may show that this segment is at the highest locked state.
CHEN Changyun,HE Jianming. Analysis of the Motion and Deformation Characteristics of Subordinary Segments of the West Qinling Fault[J]. jgg, 2016, 36(9): 784-788.