Convection Inside the Mantle

Most of what we know about Earth&rsquo;s interior comes from observing how seismic waves&ndash;mostly from earthquakes&ndash;bounce around. As our observations have gotten better&ndash;more seisometers, better imaging techniques&ndash;scientists have identified two large anomalies sitting near the bottom of the mantle . (Image credits: E. Garnero and C. Richardson ; see also Physics Today )