Coseismic deformation and source characterisation of the 21 June 2022 Afghanistan earthquake using dual-pass DInSAR

On 21 June 2022 (at 20:54:34UTC), a magnitude 6.0 (Richter scale) earthquake (depth 4 km) struck eastern Afghanistan, devastating parts of the Khost and Paktika provinces. With its epicentre located southwest of Khost city, more than 1000 people were killed and several thousands injured by the earthquake. Deformation modelling and finite-fault source characterisation provide essential information for seismic hazard management and advanced analysis of the seismicity in earthquake prone areas. The coseismic deformation, which occurred west of the NNE-SSW-trending North Waziristan-Bannu thrust fault zone, was assessed using dual-pass (ascending and descending) interferometric Sentinel-1 data. The line of sight (LOS) displacement estimated from ascending pass imagery ranged from + 0.38 m to - 0.16 m. The descending pass LOS displacement ranged from + 0.10 m to - 0.13 m. The displacement components are resolved in vertical and east-west directions using ascending and descending passes. The displacement is predominantly westward with a strong upliftment component, thus indicating an SW-trending oblique slip movement of the fault. Inversion modelling was done to derive the seismic source characteristics from DInSAR displacement values using an elastic dislocation model. The linear inversion model converges at a single fault source solution with a dip and strike of similar to 62 degrees and 216 degrees N, respectively, having a rake of 25 degrees N. The distributed slip values vary between 0 and 2.25 m. The inversion model results in a moment magnitude of 6.18 and a geodetic moment of 2.06 x 10(18) Nm, comparable to those derived using teleseismic body wave data by USGS. Damage assessment using optical data from the Worldview-1 satellite substantiates that the building damages are located primarily within the zone of surface deformation.

Automated summary

On June 21, 2022, a magnitude 6.0 earthquake struck eastern Afghanistan, causing severe damage in the Khost and Paktika provinces. With the epicenter located southwest of Khost city, the earthquake resulted in over 1000 deaths and several thousand injuries. Deformation modelling and source characterization using satellite data provide valuable information for seismic hazard management.