Ridges, hotspots and their interaction as observed in seismic velocity maps

A new global S-wave velocity model reveals that although mid-ocean ridges and hotspots are both underlain by low-velocity anomalies in the mantle, these have distinctly different structures. This implies that there are differences between the upwelling mechanisms under ridges and under hot-spots. The velocity model also shows that there may be interactions between ridges and hotspots near Afar and St Helena.