Coseismic surface deformation analyses using SAR and optical images: 2023 Kahramanmaraş earthquake sequence, Türkiye

The 2023 Kahramanmaraş earthquake sequence in Türkiye, including Mw 7.7 and 7.6 mainshocks, caused significant surface ruptures along the East Anatolian Fault (EAF) and Sürgü–Çardak Fault (SCF). We calculated the coseismic displacement fields through pixel offset tracking (POT) analysis of Sentinel-1 SAR data and optical image correlation (OIC) analysis of Sentinel-2 imagery. Our results reveal distinct sinistral motion along both the EAF and SCF, with maximum offsets of about 7 and 9 m, respectively. Deformation zones were identified both on and off the fault, highlighting the relationship between the rupture geometry and the broader deformation field. A comparative evaluation of the POT and OIC methods showed that while POT captures broad deformation patterns over large areas, OIC provides higher-resolution details essential for understanding localized deformation. However, georeferencing accuracy and resolution differences between SAR and optical images remain challenges that can affect the comparison of results. This study underscores the importance of integrating multiple remote sensing techniques for accurate and detailed assessments of earthquake-induced surface deformation.