Fig. 9

Numerical simulations for Ps reflected waves. a The source location of D/V Chikyu was set at the sea surface. Bathymetry is flat. The red triangles represent the six OBSs, whose relative horizontal locations with respect to D/V Chikyu were preserved. The physical properties at each layer are summarized in Tables 3, 4, 5. b Ps amplitudes reflected at layer 3 as a function of Vs reductions in Table 3 for the six OBSs, yellow: OBS01, black: OBS02, light-blue: OBS03, orange: OBS04, red: OBS05, and magenta: OBS06. The two dashed arrows show the Vs reduction at OBS04 for an amplitude variation of 0.0002