Fault geometry, slip distribution and potential triggering of the 2022 MW 6.3 deadly Afghanistan earthquake revealed from geodetic and weather data

An Mw 6.0 earthquake struck Khōst, Afghanistan on June 22, 2022, killing more than 1,700 people and devastating the region. For studying this earthquake, we computed coseismic deformation fields produced by the earthquake using the Sentinel-1 Terrain Observation with Progressive Scans (TOPS) Interferometric Synthetic Aperture Radar (InSAR). The InSAR results show that the maximum coseismic displacement in the satellite Line of Sight (LOS) direction reached up to 39 cm. We determined the geometric parameters of the fault and coseismic slip distribution from these InSAR measurements. The best-fitted fault model shows that the rupture occurred on a right-lateral strike-slip fault with a strike of 203.7° and a dip of 68°. The most slip is concentrated at a shallow depth within the upper 10 km with the maximum slip of ~3 m at 2.5 km depth. The maximum slip produced by this earthquake is significantly larger than the slip produced by the previous earthquakes in this region with similar magnitudes. The focused shallow slip is likely the reason for the significant damage produced by this earthquake. Heavy rainfall and the favorable Coulomb stress change (CSC) of the 2015 Mw 7.5 Hindu Kush earthquake had likely a triggering effect on the occurrence of this event. Heavy rainfall occurred near the epicenter of the earthquake about 10 hours prior to the mainshock. The favorable impact of the Hindu Kush earthquake on this event suggests that seismicity in Afghanistan is controlled by the ongoing subduction of the Indian plate beneath the Eurasian plate along their west boundary.