How do scientists know where an earthquake has occurred and how strong it is?They use seismographs. Seismographs are instruments that record the vibrations from an earthquake. The waves are recorded onto a seismogram, or a record of the waves.

Key terms:

Seismograph: An instrument that detects records and measures the vibrations caused by an earthquake.

Seismogram: The record made by a seismograph; the paper on which earthquake waves are recorded.

Magnitude:A measure of the total amount of energy released at the source of an earthquake.

Amplitude: The size of the recorded wave.

Focus: The point where the earthquake occurs. the plates break and energy is released from.

Epicenter: Point on the earth's surface directly above the focus.

-closest point on the earth's surface to

focus

-Will receive the strongest waves