Fig. 1.

Mechanical waves in the subsurface region of a nearly incompressible linear elastic medium (mimicking soft tissue) simulated in OnScale. Spatial and temporal parameters of the push are $d=250\mu \mathrm{m}$ and $T=100\mu \mathrm{s}$, respectively; shear wave speed is $C_s=5\mathrm{m}/\mathrm{s}$ ($\mu =25\mathrm{kPa}$). Left column: semi-infinite material with air at the upper boundary; and the right column: a 1-mm thick tissue layer bounded with a liquid from the bottom. (a), (b) Diagrams for wave excitation and propagation (taken from Ref. 5); (c), (d) wave fields (XT plots) along the medium surface displayed over an arbitrary dynamic range scaled to the signal maximum; (e), (f) temporal profiles of Rayleigh and guided waves at a 10-mm distance from the excitation point (shown with a white dashed line), respectively; and (g), (h) phase velocity dispersion plots for Rayleigh and guided waves, respectively: numerical simulation (red crosses) superimposed on the analytical solution (solid lines).⁵ Dynamic variations of the waveforms are presented in Video 1 (MP4, 498 MB [URL: https://doi.org/10.1117/1.JBO.24.7.076003.1]).