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.
"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
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
This layer appears to glide over a weaker region below called the asthenosphere, characterized by high seismic attenuation and low shear wave velocity.
From Science Daily • Sep. 27, 2023
Unlike the lithosphere that consists of multiple plates, the asthenosphere is relatively unbroken.
From Textbooks • Jan. 1, 2017
Rocks in the asthenosphere are under so much pressure that they move in and out of solid form—sometimes they are solid rocks, sometimes liquid magma.
From "Meltdown" by Deirdre Langeland
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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.