Shock compression experiments have been performed on pure synthetic singlecrystal forsterite (MgSiO4) in the pressure range 15--93 GPa using a newly installed two-stage light gas gun. The value of the Hugoniot elastic limit (HEL) vary with the shock propagation directions with respect to the crystallographic orientations, reflecting a notable elastic anisotropy in the olivine crystal. The largest value of HEL up to 12 GPa is observed in the shock direction parallel to <010>. In the hydrostatic regime, shock data in the shock velocity-particle velocity (Usμ&rgr;) plane are segmented into two parts by a transient plateau starting at around Us = 8.4km/s indicating a phase transition. For the shock data of the low-pressure olivine phase below about 50 GPa, a linear fit with the equation Us = C0+su&rgr; has yielded parameters of C0 = 6.26 km/s and s = 1.12. The value of C0 is close to the bulk sound velocity of forsterite. Murnaghan-Birch fit of shock data for the low-pressure olivine phase incorporate with the static compression data by Olinger (1977) has resulted in K0 = 132 GPa and K0' = 3.4, which are in reasonable agreement with the ultrasonic data. The close correspondence of the present shock data to the observation of shock residual effects in olivines is noteworthy. The appearance of melt zone or diaplectic glass observed above about 50 GPa seems to correspond to the onset of the phase transition inferred in the present measurements.