All components of the averaging kernel for v_z inversion at 1 Mm depth with a FWHM of s_z = 1.1 Mm and s_h = 15 Mm. Bottom row: with cross-talk minimised, top row: cross-talk is ignored. The cross-talk is presented in the form of and averaging kernel components. Random error of the results is 3 m s^-1 when assuming data averaged over 4 days. Over-plotted contours, which are also marked on the colour bar for reference, denote the following: half-maximum of the kernel (white), half-maximum of the target function (black), and by grey lines  ± 5% of the maximum value of the kernel (solid and dotted, respectively).