Construction and analysis of InSAR seismic catalog for medium-to-strong earthquakes in the Sichuan-Yunnan region

To systematically analyze the mechanisms of medium-to-strong earthquake generation in the Sichuan-Yunnan region, this study conducts research on the refined coseismic deformation field construction and the automatic extraction strategies for earthquake parameters, and develops a Sichuan-Yunnan geodetic earthquake catalog based on InSAR data. Sentinel-1 SAR interferometric pairs were utilized to construct high-precision coseismic deformation fields of nine earthquakes (5.0≤MW≤6.5 and depths≤20 km) in the Sichuan-Yunnan region between October 2014 and December 2023. After applying atmospheric errors corrections, the focal depth and fault geometry parameters were obtained through inversion. The study quantitatively analyzed the effects of atmospheric correction on the source parameter inversion. The analysis shows that atmospheric errors correction effectively ensures the quality of the InSAR-based source parameter inversion results. By comparing with the seismic catalogs released by institutions such as GCMT and CENC, we summarized the spatial discrepancies and characteristics of InSAR earthquake catalog compared to conventional catalogs in locating medium-to-strong earthquakes. The results demonstrate that the fault strike, dip, and rake angles derived from InSAR inversion are generally consistent with the GCMT and CENC catalogs. The focal depths from InSAR inversion are shallower, clustering above 10 km. Although the inverted horizontal epicenter locations show a significant systematic offset compared to the GCMT records, considering that InSAR deformation fields can better reflect the macroscopic location of seismogenic faults, it is concluded that the GCMT catalog exhibits systematic east-west errors in the Sichuan-Yunnan region.