Acoustic wavefields at 600 ms in different graben models by the proposed scheme. The top rows (a, b, and c) display horizontal component particle velocity wavefields, and the bottom rows (d, e, and f) exhibit vertical component particle velocity wavefields. Columns (a) and (d) represent acoustic wavefields in the horizontal surface model. Columns (b) and (e) correspond to acoustic wavefields in the smooth surface model, calculated using the suggested approach. Columns (c) and (f) show acoustic wavefields in the unsmooth surface model, also computed by the proposed method.