Coseismic deformation and fault slip inversion of the 2017 M_W7.3 Halabjah, Iraq, earthquake based on Sentinel-1A data

In this study, firstly, based on Sentinel-1A radar satellite images of Europe Space Agency, the coseismic deformation field covering the whole 2017 M_W7.3 Halabjah, Iraq, earthquake region was obtained by using two-pass interferometry technique. The result shows that the main deformation region caused by the Halabjah earthquake is about 60 km×70 km, which distributes along the Zagros main front fault. Uplift occurred in the southwestern part with 88 cm at most along the line of sight, while in the northeastern subsidence occurred with 37 cm at most along the line of sight, the displacement indicates that the seismogenic fault is characterized by thrusting movement. Then nonlinear multi-peak particle swarm optimization algorithm and linear steepest descent method with rectangular dislocation model in elastic half-space are used to estimate the fault geometric parameters and coseismic slip distribution. The inversion results suggest that the seismogenic fault is dominated by thrust movement with a little right-lateral strike-slip component, and the maximum slip is about 3.34 m. The seismic moment from inversion is 1.68×10²⁰ N·m （M_W7.4）, which is consistent with the result of seismology.