asthenosphere

as·then·o·sphere  (s-thn-sfîr)

n.

A zone of the earth's mantle that lies beneath the lithosphere and consists of several hundred kilometers of deformable rock.

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[Greek asthens, weak; see asthenia + sphere.]

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asthenosphere [əsˈθiːnəˌsfɪə -ˈθɛn-]

n

(Earth Sciences / Geological Science) a thin semifluid layer of the earth (100-200 km thick), below the outer rigid lithosphere, forming part of the mantle and thought to be able to flow vertically and horizontally, enabling sections of lithosphere to subside, rise, and undergo lateral movement See also isostasy

[from astheno-, from Greek asthenēs weak + sphere]

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asthenosphere  (s-thn-sfîr)

The upper part of the Earth's mantle, extending from a depth of about 75 km (46.5 mi) to about 200 km (124 mi). The asthenosphere lies beneath the lithosphere and consists of partially molten rock. Seismic waves passing through this layer are significantly slowed. Isostatic adjustments (the depression or uplift of continents by buoyancy) take place in the asthenosphere, and magma is believed to be generated there. Compare atmospherehydrospherelithosphere

Thesaurus

Noun

1.

asthenosphere - the lower layer of the crust         layer - a relatively thin sheetlike expanse or region lying over or under another crust, Earth's crust - the outer layer of the Earth