The compliance at (a,e) and beneath (b–d, f–h) the solid medium surface (Table 1). The compliance at depth is computed for frequencies of 0.2 (b, f), 2.09 (c, g) and 5 Hz (d, h). The 2.09 Hz frequency corresponds to the air-coupled Rayleigh-wave activation (inset in a). The black and red curves represent the vertical and horizontal compliance values, respectively. The solid curves are for the elastic medium (Table 1), while the dotted curves are for the same medium with an attenuation factor of Q_μ = 300. The compliance computation of anelastic media is detailed in Section 6.1. The horizontal grey dashed line in each subplot (b–d, f–h) marks the depth equal to one wavelength.