Earthquake Vocabulary

Earthquake

Vibrations in the earth caused by the sudden release of

energy, usually a result of the movement of rocks along a

fault.

Fault

A fracture in bedrock, along which the

opposite sides of the fracture move in

opposite directions.

FocusThe location where the rupture of an earthquake begins and

energy is released. This happens below the earth’s surface.

Epicenter

The point on the surface of the earth directly above the focus of

an earthquake.

AftershockAn earthquake that follows

the main shock of an earthquake.

Seismograph

The instrument that detects, records, and measures the vibrations produced by an

earthquake.

Seismogram

The record made by a seismograph; the paper on

which earthquake waves are recorded.

Richter ScaleThe scale used to categorize the intensity of earthquakes

Plate TectonicsA theory stating that the

earth’s surface is broken into plates that move.

Plate

A large section of the earth’s surface made of the crust and the rigid top part of the mantle.