Frictional Heterogeneity Governs Slip Partitioning and Seismic Hazard in the 2023 Turkey Earthquake Doublet

Abstract Quantifying fault frictional properties is fundamental to understanding slip behavior and seismic hazard. We analyze 2 years of Sentinel‐1 SAR data following the 2023 Turkey earthquake doublet using Independent Component Analysis‐enhanced Small Baseline Subset‐InSAR, to resolve postseismic deformation and invert for afterslip on the East Anatolian and Çardak faults. Within a rate‐and‐state framework, we estimate the friction parameter in postseismically stable regions ( R 2 > 0.9), showing that afterslip dominantly occurs in high velocity‐strengthening regions, whereas coseismic rupture and aftershocks cluster near low zones or adjacent unstable patches. Depth‐dependent slip partitioning indicates a brittle–ductile transition modulated by frictional heterogeneity, and eastward migration of deep afterslip and segmentation of slip behavior highlight postseismic deformation complexity. Elevated values on the Pütürge segment indicate rupture propagation was limited by velocity‐strengthening regions. These results suggest that frictional heterogeneity likely governs slip partitioning and provide quantitative constraints for seismic hazard assessment in continental fault systems.