asthenosphere

American  

[as-then-uh-sfeer] / æsˈθɛn əˌsfɪər /

noun

Geology.

1. 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.

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asthenosphere British  

/ əsˈθiːnəˌsfɪə, -ˈθɛn- /

noun

1. 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

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asthenosphere Scientific  

/ ăs-thĕn′ə-sfîr′ /

1. 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.

2. Compare atmosphere hydrosphere lithosphere

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Etymology

Origin of asthenosphere

First recorded in 1910–15; from Greek asthen(ḗs) “frail, weak, sickly” + -o- + -sphere; see asthenia

Compare meaning

How does asthenosphere compare to similar and commonly confused words? Explore the most common comparisons:

• lithosphere vs. asthenosphere

Example Sentences

These observations suggest that the oceanic asthenosphere must contain water.

From Science Daily • Sep. 27, 2023

"The presence of water in the asthenosphere can provide important insights into volcanic and seismic activities, thus facilitating their prediction and detection," he speculates.

From Science Daily • Sep. 27, 2023

The exact reasons behind these distinct properties and how they enable the lithosphere to move over the asthenosphere are not clearly understood.

From Science Daily • Sep. 27, 2023

Isostasy describes the equilibrium that exists for the earth’s lithosphere, where denser lithosphere “sinks” lower on top of the asthenosphere and less dense lithosphere “floats” higher on the asthenosphere.

From Textbooks • Jan. 1, 2017

The puzzle pieces, called tectonic plates, sit on the asthenosphere, a layer of Earth that shifts and flows.

From "Meltdown" by Deirdre Langeland