image: The asthenosphere (yellow) is a layer that lays below the cold mobile plates (blue) and the upper mantle (green). Beneath spreading plates mantle material upwells over a broad region and is well mixed (heavy stippling) while beneath large ocean plates there is significant shearing but less efficient mixing (light stippling). Oceanic hotspots are concentrated beneath slow-wavespeed regions (red) that may be associated with the asthenosphere. This material relates to a paper that appeared in the Dec. 5 2014 issue of Science, published by AAAS. The paper, by D.L. Anderson at California Institute of Technology in Pasadena, CA, and colleagues was titled, "Driving the Earth machine?" view more
Credit: [Credit: Scott King]