Fig. 6

Comparison of the measured phase velocities (red dots with error bars) and predicted tsunami phase velocities for the 2011 Tohoku-Oki earthquake tsunami. The half of the error bar length at each wave period corresponds to one standard deviation of 25 station measurements. The measured phase velocities fit the predicted tsunami phase velocity of the gravitationally-coupled elastic Earth model, i.e., the PREM model. Two other theoretical tsunami phase velocity models are plotted. The dashed line represents a non-dispersive constant long-wave tsunami speed given by \(\omega /k=\sqrt{gd}\), where g = 9.822 m/s² and \(d=\) 4 km. The dash-dotted line expresses the linear surface gravity wave given by \(\omega /k=\sqrt{g(\mathrm{tanh}kd)/k}\). The figure has been adapted and modified from Fig. 9 of Watada et al. (2014)