Refining 3D Displacement Fields and Coseismic Slip Models of the 2023 Kahramanmaraş Earthquakes Using Subswath and Burst Overlap Interferometry (SBOI)

The 6 February 2023 Kahramanmaraş Earthquakes caused extensive deformation along the East Anatolian Fault Zone, producing significant north-south displacements. Standard Interferometric Synthetic Aperture Radar (InSAR) methods face significant challenges in resolving near-field deformation due to phase decorrelation caused by high displacement gradients. This study demonstrates the capability of Subswath and Burst Overlap Interferometry (SBOI), which leverages all possible overlap regions of Sentinel-1 TOPS mode to retrieve along-track deformation and improve the resolution of 3D displacement fields. We introduce an enhanced methodology that calculates pixel-based scaling factors for spectral separation, enabling accurate deformation measurements in both burst and subswath overlap regions. Although overlap regions are spatially discontinuous and cover only of the frame, SBOI offers critical constraints that complement conventional SAR, enabling full spatial coverage. We combine SBOI with azimuth and range offsets to produce 3D displacement fields and perform unsmoothed Bayesian slip inversion. Results reveal significant improvements in constraining north-south deformation, reducing residuals, and decreasing uncertainties in the slip inversion model compared to solutions without SBOI. Linear regression analysis between solutions with and without SBOI demonstrates reduction in RMS error for the north-south component of 3D displacement field. Near-field SBOI profiles also capture detailed deformation gradients along fault ruptures, offering insights into fault kinematics and rupture dynamics. This study highlights SBOI as a powerful tool for resolving high-gradient deformations and enhancing 3D displacement fields and geodetic slip models, particularly in regions experiencing large coseismic deformation with significant north-south components, where conventional InSAR and SAR measurements are insufficient.