Fig. 3

Assumed seismic velocity structure model in the 3D simulations. Upper panels show depth variations of the topography, bedrock, and upper surface of the Philippine Sea slab (PHS). The dashed gray rectangle represents the horizontal coverage of the model for 3D simulations. Assumed S-wave velocity structure along the X–Y profile is shown in the bottom subfigure. Blue and white areas represent seawater (VP = 1.5 km/s, VS = 0.0 km/s, and ρ = 1.0 g/cm3) and air (VP = VS = 0.0 km/s and ρ = 0.001 g/cm3) columns, respectively