We computed the global wavefield excited by Model III using the spectral element method (SEM) (1) for a 3D Earth model composed of mantle model s20rts (1), model Crust 2.0 (2), and topography from ETOPO5. We show the predicted velocities and displacements on the Earth's surface as movies. The 3D simulations were used to calibrate the effect of 3D structure on the 1D waveforms used in the inversion for Model III. By comparing the fits of synthetics computed for different models to data that were not used in the inversions these synthetics can be used to distinguish between models.This was done qualitatively when developing model III to estimate the improvements between successive versions of the model. The waveforms for model III match the overall amplitude and directivity in observed seismograms (Fig. S1) over a wide