Fig. 5

Synthetic test of two time windows in the vertical component for the deconvolution. a Velocity and density models for calculating the synthetic RFs. The dashed lines indicate the P- and S-wave velocity models based on the results of the tomographic inversion at station q4. The red, blue, and black lines represent the assumed P-wave, S-wave, and density models derived from the original model (the dashed lines). The red and blue arrows show the top of the basement and the Moho of the PAC, respectively. b Synthetic waveforms in the (top) vertical and (bottom) radial components for a slowness of 0.062 s/km and at a frequency band of 0.5–2.0 Hz. The waveform in the red box was used for the deconvolution to calculate the RF at the bottom of panel (c). The peak indicated by the gray arrow is produced by PwP (reflected-P wave from sea surface). c Radial RFs using (top) a time window from − 2 to 20 s in the vertical component and (bottom) a time window from − 2 to  3 s in the vertical component. The peaks indicated by the red and blue arrows are produced by the subseafloor boundaries indicated by the top of the basement and the Moho of the PAC, respectively, which are indicated by the red and blue arrows in a. The peak indicated by the black arrow is produced by PsSs (multiple reflections in the sediment). The peak indicated by the gray arrow is produced by PwPs (multiple reflections caused by a seawater layer)