noun
asthenosphere
Geological term for the ductile upper mantle layer beneath the lithosphere.
アセノスフェアはプレートテクトニクスにおいて重要な役割を果たす。
The asthenosphere plays an important role in plate tectonics.
Borrowed from English 'asthenosphere', from Greek 'asthenēs' (weak) + 'sphaira' (sphere).