Earthquake: a movement or trembling of the ground that is caused by a sudden release of energy when rocks along a fault move.
Elastic Rebound: the sudden return of elastically deformed rock to its undeformed shape.
Focus: the location within Earth along a fault at which the first motion of an earthquake occurs.
Epicenter: the point on Earth's surface directly above an earthquake's starting point, or focus.
Seismology: the science or study of earthquakes and their phenomena.
Seismograph: an instrument that records vibrations in the ground.
Magnitude: a measure of the strength of an earthquake.
Intensity: in Earth science, the amount of damage caused by an earthquake
Tsunami: a giant ocean wave that forms after a volcanic eruption, submarine earthquake, or landslide.
Seismic Gap: an area along a fault where relatively few earthquakes have occurred recently but where strong earthquakes are known to have occurred in the past.