Waveforms calculated for the basin model. The locations of observation points are shown in Fig. 9. The x-, y- and z-components of waveforms are shown from top to bottom of each panel. The incident wave is a plane SH wave with an incidence angle of 0 and its shape is a Ricker wavelet of centre frequency 0.2 Hz. The P- and S-wave velocities of the basement are 4.8 and 2.8 km s^{− 1}, respectively, and the density is 2.4 g cm^{− 3}. The P- and S-wave velocities of the basin are 2.3 and 1.5 km s^{− 1}, respectively, and the density is 2.1 g cm^{− 3}.