Process
Seismometers record ground movements in the form of seismic waves resulting from earthquakes or controlled explosions. These instruments are sensitive enough to record ground movement with a displacement 1000 times smaller than the width of a human hair (3x10−8 m). A compilation of arrival times, sometimes millions of data, allows seismologists to have a clearer picture of the location and size of sub-surface structures. The result is a 3D image of a slice through the earth that serves as a seismic velocity map. The image depicts where seismic waves were able to travel faster or slower based on the differing arrive times of the waves. This in turn warrants the interpretation of the thermal structure for the deep Earth.
Read more about this topic: Seismic Tomography
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