What is the asthenosphere?

Answer

The asthenosphere is a layer of the Earth's interior that includes part of the lower crust and part of the mantle. The upper boundary of the asthenosphere is roughly 50 miles below the ground's surface. Its lower boundary, however, is inconsistent and depends primarily on temperature. Experts at the United States Geological Survey estimate its average thickness as 112 miles.

Asthenosphere comes from the Greek word "asthenos," which means "weak." This is a reference to the asthenosphere's fluidity and mechanical weakness. According to geologists at San Diego State University, the upper portion of the asthenosphere is semi-solid, but in many places its lower regions are molten. The asthenosphere is composed of iron-magnesium silicates and has an overall consistency akin to hot tar. Molten rock in the Earth's deeper layers is much hotter and behaves as a true liquid.

The region directly above the asthenosphere is the lithosphere, the entirely solid uppermost region of the Earth's crust. Earthquakes that occur in the lithosphere are potentially catastrophic because of the severe jarring forces created when two tectonic plates interact. Because the asthenosphere is more malleable, the deep-zone earthquakes that occur in it often go undetected. The United States Geological Survey reveals earthquakes also occasionally occur even deeper in the layers below the asthenosphere.

Q&A Related to "What is the asthenosphere?"
The asthenosphere is part of earths crust, and can be found below the lithosphere. It is considered the upper mantle. It is pretty hot at a temperature of 1600 degrees Celsius, but
http://www.ask.com/web-answers/Science/Nature/what...
The asthenosphere is that part of the Earth which is viscous and undergoes ductile deformation and convection on a geological time scale. It is part of the upper mantle and is approximately
http://wiki.answers.com/Q/What_is_the_asthenospher...
The lithosphere encompasses everything between the asthenosphere and the surface. It is a rigid layer, brittle in many regions depending upon its age, and an average of 160 miles
http://www.ehow.com/info_8640564_floats-top-asthen...
The asthenosphere is the mechanically weak ductily-deforming region...
http://www.chacha.com/question/what-is-an-asthenos...
1 Additional Answer
Ask.com Answer for: what is the asthenosphere
as·then·o·sphere
[as-then-uh-sfeer]
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.
Source: Dictionary.com
Explore this Topic
The asthenosphere is a part of the Earth's crust. The plates of the lithosphere slide on the asthenosphere, which is slightly fluid and very, very hot. You can ...
The asthenosphere is a part of the Earth's mantle, lying just below the crust and the lithosphere. The asthenosphere is made up of rock, and it contains more iron ...
The asthenosphere is the highly viscous but mechanically weak and ductile deforming upper mantle of the earth. It lies just below the lithosphere, and it is made ...
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