Fig. 2.

Transverse acoustic wave velocities of MgSiO₃ glass (gray circles) as a function of pressure up to 203 GPa. The white circles indicate the results on SiO₂ glass by Murakami and Bass (16). The velocity trajectories for the distinct pressure regimes are shown as blue, green, and orange lines with increasing pressure. Numbers indicate the potential Si-O coordination number within each pressure regime. Approximate pressure boundary for each Si-O coordinated structure are shown as the vertical dot lines. Error bars are ± 1σ from mean.