Co-seismic Deformation Analysis of Qinghai Maduo Ms7.4 Earthquake Based on Optical Remote Sensing and SAR Images

objectives: The Ms7.4 earthquake occurred in Maduo, Qinghai Province on May 22, 2021, which is a rare powerful earthquake that occurred in Bayan Har block in recent years, it is essential to study the characteristics of its co-seismic deformation field. Method: Based on sentinel-2 and Landsat8 images before and after Maduo earthquake, East-West and South-North two-dimensional co-seismic deformation fields were obtained by optical Pixel Offset Tracking. InSAR was utilized to obtain LOS co-seismic deformation based on Sentinel-1 ascending and descending images, and SAR Pixel Offset Tracking was utilized to obtain range and azimuth directions co-seismic deformation of the earthquake, meanwhile, 3D co-seismic deformation field of this earthquake is calculated, moreover, the results of co-seismic deformation field extracted are compared and verified. Results: The experimental results show that: co-seismic deformation field characteristics of Maduo earthquake based on optical and SAR images are great consistent. Maduo earthquake is a typical left-lateral strike-slip event, the co-seismic deformation is dominated by East-West horizontal movements, and the seismogenic fault is Jiangcuo fault. Based on optical images, it is obtained that East-West and North-South deformation of the earthquake are about ±1.60m and ±0.60m. Based on SAR images, the maximum LOS uplift and subsidence of ascending are about 1.29m and -1.12m, and descending are about 1.15m and -1.26m. In the 3D co-seismic deformation field, the East-West deformation is about -2.00m to 1.70m, North-South deformation is mainly concentrated in -1.00m to 0.50m, and it moves alternately up and down along both sides of the fault zone in Vertical direction, the deformation is about ±0.3m. The magnitude of deformation values on north side of the earthquake is larger than that on south side. Branch ruptures are shown at the end of the Southeast(34.48° N, 99.04° E) and Northwest(34.76° N, 97.61° E) of the surface rupture, and South side of Eling Lake (34.74° N, 97.75° E), and aftershock sequence is distributed near these branch ruptures. Conclusion: InSAR and Pixel Offset Tracking technology complement each other, which provides an effective way to obtain the complete co-seismic deformation field, and multi-platform, high-resolution optical and SAR images provide important datasets.