Advertisement Upgrade to remove ads


the thin and solid outermost layer of the Earth above the mantle


the layer of rock between the earth's crust and core


the central part of the Earth below the mantle


the solid, outer layer of the earth that consists of the crust and the rigid upper part of the mantle


the soft layer of the mantle on which the lithosphere floats


The strong, lower part of the mantle between the asthenosphere and the outer core

tectonic plate

a block of lithosphere that consists of the crust and the rigid, outermost part of the mantle

continental drift

the hypothesis that states that the continents once formed a single landmass, broke up, and drifted to their present locations

sea-floor spreading

the process by which new oceanic lithosphere forms as magma rises toward the surface and solidifies

plate tectonics

the theory that explains how large pieces of the Earth's outermost layer, called tectonic plates, move and change shape

convergent boundary

the boundary formed by the collision of two lithospheric plates

divergent boundary

the boundary between two tectonic plates that are moving away from each other

transform boundary

the boundary between tectonic plates that are sliding past each other horizontally


stress that occurs when forces act to squeeze an object


Stress that occurs when forces act to stretch an object


the bending of rock layers due to stress


a break in a body of rock along which one block slides relative to another

normal fault

a fault in which the hanging wall moves down relative to the footwall

reverse fault

A fault in which the hanging wall moves up relative to the foot wall

strike-slip fault

opposing forces cause rock to break and move horizontally

folded mountains

When rock layers are squeezed together and pushed upward.

fault-block mountains

Form when tension causes large blocks of rock to drop down in relation to other rocks. Tilting of rock layers can occur as tension pulls the rock layers apart.

volcanic mountains

Mountains that form when magma erupts onto Earth's surface.

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions above and try again


Reload the page to try again!


Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

NEW! Voice Recording