Co-Seismic Rupture Distribution of the Türkiye Double Earthquakes Estimated Based on Priori-Constraints and InSAR Data

Two destructive earthquake with magnitude greater than 7.0 occurred in Türkiye on February 6, 2023. So far, there are still large differences in the seismic rupture models of Türkiye obtained with different observations. Among them, the finite fault model given by United States Geological Survey is the most accurate comprehensive model available at present. Therefore, by adopting the finite fault model from the USGS as the prior model, we invert thecoseismic rupture distribution of twins strong earthquakes inTürkiye, by using the InSAR observation data from Sentinel-1. Our results reveal that: (1) The total seismic moment obtained from the inversion is 1.626 8 × 10²¹ N∙m, which is equivalent to a large earthquake with a magnitude of M_w8.1; (2) The rupture on the East Anatolian Main fault is mainly concentrated in the range of 0-15 km underground and the rupture on the Çardak-Sürgü Fault zone, but the rupture in the northern branch fault of East Anatolian fault is mostly focused in the depth range of 5-20 km. In the East Anatolian Main fault, the rupture presents two obvious high-value zones. One located at the intersection of the Narlıdağ Fault Zone and the East Anatolian Main Fault, and the other located approximately 65 km southwest of the intersection of the Narlıdağ Fault Zone and the East Anatolian Main Fault. The maximum strike-slip component of the rupture can reach 9.0 m and the maximum dip-slip component is approximately 3.0 m. In the Çardak-Sürgü Fault, the general pattern also shows two high-value zones, one located near the epicenter of the earthquake of magnitude 7.5 in Türkiye and one at the intersection of the southeast-northwest-trending and northeast-southwest-trending faults in the northwest corner of the Çardak-Sürgü Fault. The maximum value of the strike-slip component is approximately 8.1 m and the maximum value of the dip-slip component is approximately 6.1 m. The rupture produced by the twin earthquake in Türkiye is dominated by the strike-slip component and supplemented by the dip-slip component. Furthermore, the twin seismogenic faults, the East Anatolian Main fault and Çardak-Sürgü Fault zone, are both generally sinistral slip in nature. However, it alsoshows there are some thrust slip and normal slip in nature on a local scale.