Аннотация:On February 6, 2023, an Mw 7.9 earthquake occurred in the western section of the East AnatoliaFault Zone (EAFZ). It was subsequently followed by an Mw 7.7 earthquake on the northern branchof the EAFZ, known as the Sürgü Fault Zone. Coseismic deformation fields were derived for theseearthquakes using joint evaluation of near-field strong motion data, Global Navigation SatelliteSystem data, and Synthetic Aperture Radar datasets. The coseismic slip distribution model wasdetermined through the joint kinematic finite fault inversion. The Mw 7.9 earthquake was a leftlateralstrike-slip event, predominantly occurring at depths up to 20 km. The earthquake displayedthree distinct asperities that correlate well with bends and stepovers along the EAFZ. The Mw 7.7earthquake also exhibited left-lateral strike-slip characteristics, with a major asperity along theÇardak Fault featuring a maximum slip of approximately 9.5 m at depths between 0 and 24 km.The occurrence of this unanticipated large Mw 7.9 catastrophic seismic event on a fault with lowintermediatestructural maturity is noteworthy. In the vicinity of immature faults with multiple jogs,stress tends to accumulate at barrier locations. When the accumulated stress near several adjacentbarriers reaches a certain threshold, it may result in the transformation of multiple barriers intoasperities, triggering cascading ruptures.