as·then·o·sphere
[as-then-uh-sfeer]
noun Geology .
the region below the lithosphere, variously estimated as being from fifty to several hundred miles (eighty-five to several hundred kilometers) thick, in which the rock is less rigid than that above and below but rigid enough to transmit transverse seismic waves.
subduction
sub·duc·tion
[suhb-duhk-shuhn]
noun
1.
an act or instance of subducting; subtraction or withdrawal.
2.
Geology . the process by which collision of the earth's crustal plates results in one plate's being drawn down or overridden by another, localized along the juncture (subduction zone) of two plates.
Origin:1570–80