The vertical-component waveforms on the solid medium surface due to a fluid pressure perturbation. The horizontal-apparent velocity is 340 m s⁻¹ (top row) or 20 m s⁻¹ (bottom row). The x-axis is the propagation time. The solid curves are from the elastic solid medium and the dashed curves are from the anelastic medium with Q = 300 (Section 6.1). The waveform computation parameters match those in Fig. 3. The solid curves in a and c are the same as in Figs 3(g) and (i). For completeness, the corresponding horizontal-component waveforms are in Fig. S5.