Abstract: On June 19, 2019, the Ms6.0 earthquake occurred in Changning County, Sichuan Province. The seismic coseismic deformation field was extracted and the focal mechanism was inverted. It is of great significance for the analysis of earthquake rupture and guiding disaster relief. Two-track differential interference processing is used to cover the two scenes of Sentinel-1A image in the area affected by Changning earthquake. Based on the research on key technologies and image features of D-InSAR, the processing methods and parameters are configured to extract the coseismic deformation field of the earthquake. The Okada model and forward modeling are used to invert and simulate the geometric parameters and deformation fields of the seismogenic fault. The results show that the deformation field of Changning earthquake is irregular elliptical shape controlled by the northwest-oriented secondary fault. The characteristics of the two sides of the fault are obviously different. The lower left side of the fault is the subsidence area, and the upper right side is the uplift area. The maximum line of sight of the two is the maximum line of sight. The deformation is 8 and 6 cm, respectively. The motion of the fault is mainly left-lateral strike-slip, the average sliding distance is about 0.38 m, and the average sliding angle is about 55°. The positive simulated deformation field is consistent with the observation results, which proves that the observation results are more reliable and improve the observation accuracy of the low coherence deformation zone.

Key words: Changning earthquake, D-InSAR, co-seismic deformation, forward inversion, fault sliping characteristics