In addition to showing the overall layered structure
of Earth, earthquake waves can be analyzed to reveal
finer-scale features within the mantle. By combining
the data from many earthquakes, subtle changes in wave
speed have been identified. Areas through which waves
move quickly tend to be cooler or consist of denser
rock. Areas where waves move slowly indicate warmer
or less dense rock. Regions of upwelling and downwelling
of material in the mantle have been mapped using this
method of seismic tomography.
The globe on the left shows surface topography. The
globe on the right shows shallow mantle tomography.
On the tomographic model, cooler areas are shown in
blue and warmer areas are shown in red.
! After the file loads, click the arrow buttons to turn the globes. Examine how cool and warm areas are related to continent location.