Evolution of kinematics of the stellar component in time. From top to bottom panels we show quantities most relevant for the characterization of buckling: the mean velocity along the vertical axis ⟨υ_z⟩ (first panel), the velocity dispersion along the cylindrical radius σ_R (second panel), the velocity dispersion along the vertical direction σ_z (third panel), and the ratio σ_z/σ_R (fourth panel). Measurements were made for stars within the radius of 2R_D.