earthquake
The shaking that results from the movement of rock beneath Earth's surface
focus
The point beneath Earth's surface where rock breaks under stress and causes an earthquake
epicenter
the point on Earth's surface directly above an earthquake's focus
P Wave
A type of seismic wave that compresses and expands the ground.
S Wave
A type of seismic wave that moves the ground up and down or side to side.
Surface wave
A type of seismic wave that forms when P waves and S waves reach Earth's surface.
Mercalli Scale
a scale that rates earthquakes according to their intensity and how much damage they cause at a particular place
magnitude
The measurement of an Earthquake's strength based on seismic waves and movement along faults
Richter Scale
A scale that rates an earthquake's magnitude based on the size of its seismic waves.
seismograph
a device that records ground movements caused by seismic waves as they move through Earth
moment magnitude scale
a scale that rates earthquakes by estimating the total energy released by an earthquake