Application of CFT to R₁a), R₂c), D₁b), and D₂d). In each panel, top left: the running difference of the time-distance plot, overlaid with the contour (white dashed line) of the model function Acos(ωt − kx + φ) with the best-fitted parameters. Top right: the fitting result of ω as a function of the spatial location. The thick solid line is the weighted mean, the dashed lines indicate its uncertainties. Bottom left: the fitting result of k as a function of time. The thick solid line is the weighted mean, and the dashed lines indicate its uncertainties. Bottom right: the dispersion diagram and the calculation of phase speed V_p and its uncertainties. The fitted parameters are as follows: a) for R₁, ω = 0.0347 ± 0.00002 rad/s, k = 0.738 ± 0.002 Mm^-1, P = 181.2 ± 0.1 s, V_p = 47.0 ± 0.1 km s^-1; c) for R₂ω = 0.0350 ± 0.00003 rad/s, k = 0.727 ± 0.005 Mm^-1, P = 179.7 ± 0.2 s,V_p = 48.1 ± 0.3 km s^-1; b) for D₁ω = 0.0349 ± 0.00003 rad/s, k = 0.762 ± 0.00 Mm^-1, P = 180.0 ± 0.1 s, V_p = 45.8 ± 0.2 km s^-1; d) for D₂ω = 0.0349 ± 0.00003 rad/s, k = 0.716 ± 0.006 Mm^-1, P = 180.0 ± 0.2 s,V_p = 48.6 ± 0.4 km s^-1.