Fig. 1.
A map of events and stations (triangles) used in the construction of a 2D model along a corridor through the African Superplume. We use data from two arrays, South African and the new Ethiopia/Kenya array (19) of events arriving along a great circle in this study. SKS and SKKS exist points at the CMB are given in colored triangles, with blue indicating no delay and red >5 s. To produce the sharp jumps requires a monolithic structure denoted in heavy green lines as the ALVS, where the S velocity inside the box is reduced by 3% relative to PREM (18). We have included some example ray paths S, SKS, and SCS. The background tomographic model is the most recently updated Grand model (27).