Fig. 4

a Model dispersion curves for Rayleigh mode computed for the blind project committee’s Preferred layered-earth model. Red, yellow, green, blue are modes R₀, R₁, R₂, R₃. Blue is the effective mode R_e. b Model dispersion curves computed for the best-fit model described in this paper, as listed in Table 1. Horizontal grey lines indicate the discrepancy between the two sets of dispersion curves for frequencies 5–40 Hz