New research led by the University of Cambridge has found an unusual pocket of rock at the boundary layer with Earth's core, some 3,000 km beneath the surface. The enigmatic area of rock, which is located almost directly beneath the Hawaiian Islands, is one of several ultra-low velocity zones, which are so-called because earthquake waves slow to a crawl as they pass through them.
The research ( Nature Communications) reveals the complex internal variability of one of these pockets in detail, shedding light on the landscape of Earth's deep interior and the processes operating within it.
Earth's interior is layered like an onion: at the centre sits the iron-nickel core, surrounded by a thick layer known as the mantle, and on top of that a thin outer shell — the crust we live on. Although the mantle is solid rock, it is hot enough to flow extremely slowly. These internal convection currents feed heat to the surface, driving the movement of tectonic plates and fuelling volcanic eruptions.
