Shearwave Dispersion Ultrasound Vibrometry (SDUV) measures tissueelasticity and viscosity by quantifying dispersion of shear wave propagationvelocity. Long tone bursts of focused ultrasound are transmitted by an arraytransducer to a push origin at a pulse repetition frequency of fp toproduce multi-tone shear waves at fp and its harmonics. Shear wavesare monitored by pulse echo ultrasound transmitted by the same array transducerbetween the push tone bursts. The Voigt dispersion model is fitted to shear wavevelocities measured at multiple frequencies to estimate elasticity f1 and viscosity f2. Alternatively, f1 andf2 can be calculated from shear wave amplitude attenuation and shearvelocity at frequency, also based on Voigt model. In the present study, thesetwo approaches were compared using simulation data. Field II was used tosimulate ultrasound radiation force field generated by a linear arraytransducer. Motion in a homogenous viscoelastic medium was calculated using theGreen's function. Simulation results showed comparable estimations for bothmethods when SNR was high. When SNR was low, the amplitude attenuation methodwas more robust than the velocity method.