For ten points, name this zone of malleable rock that separates the upper and lower mantle and allows the tectonic plates to move.
Its base defines the bottom limit which P-n and S-n waves can reach, while the regular shear and longitudinal waves must reach below it. Originally dubbed the "low velocity region" because it tends to have a slowing effect on waves passing through it, its existence was proven on May 22, 1960 by analysis of waves produced in a Chilean earthquake. It is found from fifty to five hundred kilometers below the surface, directly between the Mohorovicic discontinuity and mesosphere. For ten points, name this zone of malleable rock that separates the upper and lower mantle and allows the tectonic plates to move.
Its base defines the bottom limit which P-n and S-n waves can reach, while the regular shear and longitudinal waves must reach below it.
asthenosphere