'Dynamic duo' develops framework for Earth's inaccessible interior

The image is shown from space, centered over the Pacific Ocean, with a cut-away displaying anomalous heterogeneities in the mantle of the Earth: red and blue regions depict zones where seismic waves propagate slower or faster than average, respectively. Distant earthquakes (e.g., the red star) send seismic energy throughout the planet, which traverses anomalous structure and brings information about Earth’s internal structure to the planet’s surface. The large red region beneath the Pacific Ocean sits atop the hot molten iron core (orange ball), is best explained as chemically distinct from the rest of the mantle, and possibly plays an important role in guiding convection currents in the mantle over geologic time scales. The blue regions underlay subduction zones at Earth’s surface, where cold and dense material falls into the planet in the recycling of Earth’s surface as part of plate tectonics. Thus the fields of seismology coupled with geodynamics are providing a self-consistent framework for depicting the evolution and dynamics of Earth’s interior. Credit: AAAS/Science