Wave propagation pattern from a specific event inferred from (a–c) relative arrival times and (d–f) relative logarithmic amplitudes. (a) Relative arrival time are shown in map view. The grey line denotes the trench. (b) Standard deviations of the error on the relative arrival times. (c) Relative arrival times plotted against propagation distances. The error bar denotes the standard deviation. The blue dashed line represents a regression line. (d–f) The same as (a–c), but relative logarithmic amplitudes are shown. Note that the effect of geometrical spreading is removed in (f).