A research framework for seismic slip distribution inversion considering atmospheric effects and deformation field downsampling

Traditional Interferometric Synthetic Aperture Radar (InSAR) methods have difficulties in capturing deformation information of small and medium-sized earthquakes due to small surface deformation and atmospheric interference. This study proposes a research framework for seismic slip distribution inversion considering atmospheric effects and deformation field downsampling. The research framework begins by generating multiple interferometric pairs, using the coherence thresholding method to select stable points as reference during phase unwrapping. This step includes averaging the unwrapped pairs post-phase superposition to mitigate atmospheric turbulence effects in the interferograms and effectively extract the faint coseismic deformation field. Additionally, the framework employs a saliency-based quadtree downsampling algorithm to differentiate between major and minor deformation zones, thereby streamlining the data associated with the deformation field. The Bayesian method is then used to determine the geometric parameters of the earthquake fault, with the steepest descent method (SDM) applied to invert the fault slip distribution. The methodology was tested using the March 20, 2020, Ms5.9 earthquake in Dingri County, Tibet, China as a case study. Results demonstrate that this approach reduces atmospheric influences in the deformation field and enhances the accuracy of fault slip inversion, showing high consistency with existing studies and validating the reliability of the proposed method.