asthenosphere

noun as·theno·sphere \ as-ˈthe-nə-ˌsfir \

Definition of asthenosphere

: a zone of a celestial body (such as the earth) which lies beneath the lithosphere and within which the material is believed to yield readily to persistent stresses

asthenospheric

play \-ˌthe-nə-ˈsfir-ik, -ˈsfer-\ adjective

Recent Examples of asthenosphere from the Web

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Origin and Etymology of asthenosphere

Greek asthenḗs "weak" + -o- + -sphere — more at asthenia
Note: Term introduced by the American geologist Joseph Barrell (1869-1919) in "The strength of the earth's crust. Part VI. Relations of isostatic movements to a sphere of weakness—the asthenosphere," Journal of Geology, vol. 22 (1914), p. 659: "The theory of isostasy shows that below the lithosphere there exists in contradistinction a thick earth-shell marked by a capacity to yield readily to long-enduring strains of limited magnitude…To give proper emphasis and avoid the repetition of descriptive clauses it needs a distinctive name. It may be the generating zone of the pyrosphere; it may be a sphere of unstable state, but this to a large extent is hypothesis and the reason for choosing a name rests upon the definite part it seems to play in crustal dynamics. Its comparative weakness is in that connection its distinctive feature. It may then be called the sphere of weakness—the asthenosphere…"



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