Analysis of the Slip Rate and Deformation Characteristics of Subordinary Segments of the West Qinling Fault in the Northeastern of Tibetan Plateau

The West Qinling fault can be divide into four subordinary segments, Guomatan, Zhangxian, Yuanfeng and Tianshui-Baoji. In this study , based on the GPS horizontal velocity data during 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 filed, we analyzed the slip rate and deformation along different segments of the West Qinling fault. The results show that, during 1999-2007, the characteristics of the whole fault is left strike-slip with compression, and among all the four segments, the Guomatan has the highest activity 1.1±0.3mm/a, and the Tianshui-Baoji segment is the lowest one, ~0.2±0.4mm/a; The principal strain rate along the whole West Qinling fault derived from GPS measurements show that, the principal compression strain rates are apparently greater than principal extension strain rates, but the strain rate value are obvious different, the compression strain rate of the Guomatan and Luanfeng segments are larger than the Zhangxian and Tianshui-Baoji segments. Compared with that from 1999-2007, the results during 2009-2013 show that the Zhangxian segment becomes more active, and have a relative large tensile strain rate. These changes in Zhangxian segment maybe caused by the occurrence of the MinxianZhangxian M_S6.6 earthquake, happened in July 22, 2013.These characteristics of principal strain rate of all segments of the West Qinling fault are the same as the result comes from the GPS velocity profiles. Comprehensive analysis the remote and near filed deformation characteristics acquired by the GPS velocity profiles and GPS principal strain rate filed, and we find that the whole West Qinling fault maybe in a locked state, and show strain accumulation to certain extent, among the four segments, the Tianshui-Baoji segment have the lowest activity, and this feature maybe show that this segment was at the highest locked state.