Advertisement Upgrade to remove ads


An upward fold in rock formed by compression of Earth's crust


A downward fold in rock formed by compression in earth's crust


A large area of flat land elevated high above sea level


The force that opposes the motion of one surface as it moves across another surface


A bend in rock that forms where part of Earth's crust is compressed


A break in Earth's crust where slabs of rock slip past each other

Fault-block mountain

A mountain that forms where a normal fault uplifts a block of rock


The shaking that results from the movement of rock beneath Earth's surface


A change in the volume or shape of Earth's crust


A device that records ground movements caused by seismic waves as they move through Earth


The measurement of an earthquake's strength based on seismic waves and movement along faults


The process by which an earthquake's violent movement suddenly turns loose soil into liquid mud


An earthquake that occurs after a larger earthquake in the same area


A large wave produced by an earthquake on the ocean floor

Mercalli Scale

A scale that rates earthquakes according to their intensity and how much damage they cause. Rated from I to XII. Not precise. Earthquake can have many different ratings, depending upon how far away from the epicenter it is rated.

Richter Scale

A scale that rates seismic waves as measured by a particular type of mechanical seismograph. Works well for small, nearby earthquakes, but not well for all earthquakes.

Moment Magnitude Scale

A scale that rates earthquakes by estimating the total energy released by an earthquake. Works well for all earthquakes.


Stress that stretches rock so that it becomes thinner in the middle


Stress that squeezes rock until it folds or breaks


Stress the pushes a mass of rock in opposite directions

Normal Fault

A type of fault where the hanging wall slides downwards. Tension occurs. Happens at divergent boundaries.

Reverse Fault

A type of fault where the hanging wall slides upwards. Compression occurs. Happens at convergent boundaries.

Strike-Slip Fault

A type of fault where rocks on either side move past each other sideways with little up-or-down motion. Shearing occurs. Happens at transform boundaries.

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