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Geology & Earth Sciences vocabulary · Earth's Structure

Asthenosphere

Meaning in geology & earth sciences, with examples

/æsˈθenəsfɪr/nounCommon term

In geology & earth sciences, asthenosphere means: The hot, weak layer of the upper mantle just below the lithosphere, which can flow slowly and allows the tectonic plates above it to move.

In Turkish: astenosfer

How it is used

Used in plate tectonics lectures together with lithosphere. It is mostly solid, but high temperature and a little melt make it soft and ductile. It lies roughly 100 to 350 km below the surface, although estimates of its depth vary.

Example sentences

  1. The rigid plates slide over the weaker asthenosphere.

  2. Seismic waves slow down when they enter the asthenosphere.

Common collocations

  • the lithosphere and asthenosphere
  • the upper asthenosphere
  • asthenospheric flow
  • low-velocity zone
  • lithosphereThe rigid outer shell of the Earth, made of the crust and the uppermost part of the mantle. It is broken into tectonic plates and is typically around 100 km thick.
  • mantleThe thick layer of hot, mostly solid rock between the crust and the core, reaching a depth of about 2,900 km. It flows very slowly over millions of years.
  • convection currentA circular flow in a fluid or soft solid in which hot material rises, spreads, cools and sinks again. In the mantle, it carries heat towards the surface.
  • tectonic plateOne of the large, rigid pieces of the Earth's lithosphere that move slowly over the mantle, usually by a few centimetres a year.

More terms: Earth's Structure

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