. At shallow mantle depths, there are several appreciable differences, such as the depth extent of the high velocity anomaly in the upper mantle between 144 and 148 ∘ E (Fig. 11a). However, despite the differences in the crustal models, the pattern of anomalies is fairly similar. At much greater depths (cf. Fig. 10b,d), the pattern and amplitudes of anomalies become virtually identical.