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.