Talk about leaving no stone unturned. Check out this article on tectonic plates, and how scientists are learning what drives them.
smithsonianmag.com
By setting off explosions and listening for their reverberations deep inside Earth, scientists have taken the equivalent of a CT scan of the base of a tectonic plate. The results show that the base has a thin, slippery layer that may help the plate move across a more viscous layer of rock below—and may explain what drives plate tectonics.
