asthenosphere
Americannoun
noun
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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.
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Compare atmosphere hydrosphere lithosphere
Etymology
Origin of asthenosphere
First recorded in 1910–15; from Greek asthen(ḗs) “frail, weak, sickly” + -o- + -sphere; asthenia
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Vocabulary lists containing asthenosphere
Plate Tectonics - Middle School
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Earth Science - Middle School
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Earth Science - High School
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
This difference in water content between the two layers constituting the LAB can explain the sharp velocity drops as well as the near constant attenuation observed over a wide frequency range in the asthenosphere.
From Science Daily • Sep. 27, 2023
"We experimentally determined the seismic wave attenuation characteristics, parameters for ascertaining the softness of the lithosphere and asthenosphere, under high temperature and pressure using our short-period oscillation generation technology," explains Prof. Yoshino.
From Science Daily • Sep. 27, 2023
These observations suggest that the oceanic asthenosphere must contain water.
From Science Daily • Sep. 27, 2023
The asthenosphere is the layer below the lithosphere.
From Textbooks • Jan. 1, 2017
To say that the lithosphere floats on top of the asthenosphere suggests a degree of easy buoyancy that isn’t quite right.
From "A Short History of Nearly Everything" by Bill Bryson
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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.