3D seismic wavefield snapshots using the vacuum method (a, c, e) and their 3DIBM counterparts (b, d, f), with different recording times indicated in each subfigure. The wavefield slices are positioned at x = 1275 m and y = 1950 m, traversing the source location marked by the yellow dot. Black arrows and dashed-line boxes identify differences in wave propagation between the two methods.