SPP 1257 Modelling of the Dynamic Earth from an Integrative Analysis of Potential Fields, Seismic Tomography and other Geophysical Data Effective velocity and density variations in the TZ based on traditional tomography models Parametrization, Gu et al., 2003 In fact, the observed Vs variations could be either negative or positive in the vicinity of the 660 discontinuity depending on many variable factors.
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