asthenosphere
|as-then-o-sphere|
🇺🇸
/æsˈθɛnəˌsfɪr/
🇬🇧
/æsˈθɛnəˌsfɪə/
weak, ductile layer under the lithosphere
Etymology
'asthenosphere' originates from Greek, specifically the words 'asthenēs' meaning 'weak' and 'sphaira' meaning 'sphere'.
'asthenosphere' was formed in modern scientific usage (through New Latin/English) by combining the Greek roots 'asthenēs' and 'sphaira' in the 20th-century geophysical literature to name the weak layer beneath the lithosphere.
Initially named to denote a 'weak sphere' within the Earth, the term's meaning has remained focused on a mechanically weak, ductile layer of the upper mantle, though scientific understanding has refined its physical description (e.g., partial melt, viscosity contrasts).
Meanings by Part of Speech
Noun 1
the mechanically weak, ductile region of the upper mantle of the Earth that lies below the lithosphere and on which tectonic plates move; often partially molten or of lowered viscosity.
The asthenosphere's ductile behavior allows tectonic plates of the lithosphere to move over it.
Synonyms
Antonyms
Last updated: 2025/11/06 09:56