Abstract: We used mobile GNSS observations of 1999—2007 and 2007—2013 and their processing results, and analyzed the horizontal deformation field and its changes before the November 23, 2013 Songyuan M_S5.8 earthquake in Jilin province. The results show that (1) The Songyuan M_S5.8 earthquake occurred in the region of weaker crust movement; (2) The maximum shear strain and main principal strain of this earthquake zone are almost zero in 1999—2007, which is the weakest part in the region, and still weaker in 2009—2013; (3) The earthquake zone is right rotary deformation in 1999—2007, and is transition zone for the left and right rotary deformation in 2009—2013, both of their order are weaker; (4) Crustal deformation is smaller and right rotary deformation is primary in whole area from 1999 to 2007; however, it is larger in east part of the area and left rotary deformation is primary in the area between 2009 and 2013. We think that the change is caused by the Japan M_W9.0 earthquake, but Songyuan earthquake is not occasioned by the M_W9.0 earthquake.

Key words: Horizontal deformation, Dynamic change, The 2013 Songyuan M_S5.8 earthquake, Northeast China