Tracing the paths of the earthquake waves between the plate boundaries shows some interesting anomalies in the pattern of their reflection.

The reflections of the plate boundaries of the Pacific plate and the African plate converge at a point slightly off centre. The reflections of the North American plate and the South American plate meet at a point further off centre, closer to the edge of the outer core and the mantle.

The reflections of the Arctic plate ( encompassing North America and Asia) and the Antarctic plate meet at a similar point, between South America and the outer core.

The reflections of the Arctic plate and the Antarctic plate, when overlaid with the reflections of the North and South American plates, enclose an area approximately 2,000 km wide, in the mantle.