BOB HIRSHON (host):
The engines of earth’s continents. I’m Bob Hirshon and this is Science Update.
The Earth’s continents move on a mantle of molten rock. One of the breakthroughs in science this year is new evidence of deep mantle plumes—tubes of molten rock pushing up from deep inside the planet. Science magazine deputy news editor Robert Koontz says while continental drift has been known for decades, scientists aren’t sure what does the moving.
ROBERT KOONTZ (Science magazine):
And some thought was that these big columns of rock were pushing from down below, and sort of circulating around, and they provide the oomph that pushes the continents.
Using detailed measurements of seismic waves as they move through the earth, scientists have now created images that reveal twenty-eight of these plumes reaching all the way to the earth’s core. The work will help geologists understand not only the motion of continents, but also violent activities like volcanoes and earthquakes. I’m Bob Hirshon, for AAAS, the science society.