The inclusion of amplitude constraints in body-wave inversions allows the separation of earth models which seem indistinguishable on the basis of traveltime observations. Amplitude constraints can be included through the calculation of synthetic seismograms by the quantized ray theory formulation. As an example, a preliminary model for the velocity structure of the upper mantle beneath part of the Canadian Shield is derived from P-wave amplitude and arrival-time data from Project Early Rise. The amplitude behavior observed in this data set is consistent with the existence of positive velocity gradients near 150- and 200-km depths and prominent discontinuities near 400- and 650-km depths.

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