Résumé
Abstract On February 6, 2023, southern Türkiye was hit by two major earthquakes at 01:17 UTC (Mw=7.8, Pazarcık, Kahramanmaraş) and at 10:30 UTC (Mw=7.6, Elbistan, Kahramanmaraş) leading to severe damages at the complex junction of the Dead Sea Fault (DSF), the Cyprus arc and the East Anatolian fault zone (EAFZ). The ruptures propagated along several known strands of the southwestern termination of the EAFZ, the main Pazarcık and Karasu valley faults and the Çardac-Sürgü fault. Here, we present the high-resolution mapping of the entire coseismic surface rupture and an estimation of the rupture width, the total and on-fault offset, and of the diffuse deformation obtained a few days after the two mainshocks. The mapping is derived from image correlation of optical Sentinel-2 satellite imagery and is validated with offset measurements collected on the ground. We found that the ruptures extend over lengths of 310 km and 140 km for the Mw 7.8 and Mw 7.6 mainshocks, respectively. The maximum offsets reach 7.5 ± 0.8 m and 8.7 ± 0.8 m, near the epicenters of the Mw 7.8 and Mw 7.6, respectively. We propose a segmentation of the two ruptures based on these observations, and further discuss the location of potential supershear rupture. The use of optical image correlation complemented by field investigations along earthquake faults provides new insights into the seismic hazard assessment.