Fig. 23

Comparison of 1-D S-wave velocity structure inversions using both the fundamental and the first-higher modes of Rayleigh wave (a, b, d) with that using only the fundamental modes (c, e). a Phase velocity of the fundamental mode of the Rayleigh wave. The blue points show the average phase velocities. The Markov chain Monte Carlo method calculated the posterior probabilities for 1-D average S-wave velocity structures. b Phase velocity of the first-higher mode of the Rayleigh wave. Blue points show the 1-D average phase velocities. c The phase velocity of the fundamental mode of Rayleigh waves with posterior probabilities using only fundamental modes. d S-wave velocity structure inferred by the MCMC method using both the fundamental and the first-higher modes of Rayleigh wave. The blue line shows the median velocity at each 0.1 km depth grid point. Layers 1 and 2 are well constrained despite the given loosely bounded uniform priors. e S-wave velocity structure inferred by the MCMC method using only the fundamental modes. Modified from Figs. 5 and 10 of Yamaya et al. (2021)