asthenosphere

[as-then-uh-sfeer] /æsˈθɛn əˌsfɪər/

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.

Origin

1910-15; < Greek asthen(ḗs) frail (see asthenia) + -o- + -sphere

Examples from the web for asthenosphere

Below the asthenosphere lies another layer, stronger and more solid than the asthenosphere.
If the latter was the case, it's possible that decompression melting liquefied some of the underlying asthenosphere.
These plates move on a hot flowing mantle layer called the asthenosphere, which is several hundred kilometers thick.
They move on a hot flowing mantle layer called the asthenosphere, which is several hundred kilometers thick.
Even though the asthenosphere is not totally molten, it seems to be plastic enough for sluggish convection currents to flow.
The plates move on a hot flowing mantle layer called the asthenosphere, which is several hundred kilometers thick.
Tectonic plates move on a hot flowing mantle layer called the asthenosphere, which is several hundred kilometers thick.
These plates float on top of a softer, more plastic layer in the asthenosphere.
Tectonic plates float above the more dense, flowing layer of mantle called the asthenosphere more details.

British Dictionary definitions for asthenosphere

asthenosphere

/əsˈθiːnəˌsfɪə; -ˈθɛn-/

noun

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

Word Origin

C20: from astheno-, from Greek asthenēs weak + sphere

Word Origin and History for asthenosphere

layer of the Earth's upper mantle, 1914, from Greek asthenos (see asthenia) + sphere.

asthenosphere in Science

asthenosphere

(ās-thěn'ə-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 atmosphere, hydrosphere, lithosphere.