High-resolution co-seismic fault offsets of the 2023 Türkiye earthquake ruptures using satellite imagery

Abstract

On February 6, 2023, southern Türkiye was struck by two large earthquakes at 01:17 UTC (Mw=7.8, Pazarcık, Kahramanmaraş) and 10:30 UTC (Mw = 7.6, Elbistan, Kahramanmaraş), causing severe damage 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 Çardak-Sürgü fault. Here we present the high-resolution mapping of the entire coseismic surface rupture and an estimate of the rupture width, total and on-fault offset, and diffuse deformation obtained a few days to three months after the two mainshocks. The mapping is derived from image correlation of Sentinel-2 optical satellite imagery and validated with offset measurements collected on the ground. We find 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 events, respectively. We propose a segmentation of the two ruptures based on these observations, and further discuss the location of the potential supershear rupture. The use of optical image correlation, complemented by field investigations along earthquake faults, provides new insights into seismic hazard assessment.