Fig. 7

Example of forward modeling for OBS025 on ECr11. a Observed record section, b calculated travel times on the record section, c ray diagram, d synthetic record sections with calculated travel times. Blowups of the observed weak Pn signals are also shown. Predictive deconvolution, 4–20 Hz bandpass filter, and a gain factor proportional to distance were used to increase signal-to-noise ratios of the observed record sections. The reduction velocity is 8.0 km/s. The color of the calculated travel times corresponds to the ray path in the ray diagram. The ray paths are generated at equal distance. e Positions of the seismic lines and ocean bottom seismographs (OBSs) on the three-dimensional topographic map. OB Okigaja Bank, YS Yokogan Sone