This study investigates Coulomb stress evolution and its role in the 2017–2018 Kermanshah seismic sequence in the western Zagros. We evaluate static stress transfer from the Mw 7.3 Ezgeleh earthquake to adjacent faults, particularly the High Zagros Fault (HZF) and the Mountain Front Fault (MFF), and examine its relationship with the spatiotemporal distribution of aftershocks. Seismic data were obtained from IRSC, ISC, and USGS catalogs, and focal mechanisms from CMT solutions. ΔCFS was calculated using shear and normal stress changes and an effective friction coefficient, and compared with aftershock patterns and b-value variations.

Results indicate that the mainshock increased Coulomb stress by up to ~0.1 MPa along the northwestern HZF and southern MFF. Approximately 65–70% of aftershocks occurred within zones of positive ΔCFS, with strong spatial agreement above the 0.05 MPa threshold. Moderate aftershocks contributed to secondary seismic clustering through stress redistribution. Decreased b-values within positive stress zones suggest a higher proportion of relatively larger events. The spatial–statistical correlation between ΔCFS, aftershock density, and b-value variations demonstrates that the sequence was primarily controlled by static stress transfer, highlighting the effectiveness of Coulomb stress modeling for identifying seismically susceptible zones in the Zagros.