Humans have lived with earthquakes for a long time, and many cultures have developed ways to measure them. Devices that measure the strength (or magnitude), length, location (or epicenter), and direction of earthquakes are called seismographs. You will see how seismographs work, and how they have become more and more accurate over time.

You'll find some interesting pictures, photos, and descriptions of seismographs, which have measured earthquakes over time. A seismograph takes the motion of an earthquake and turns it into a seismogram, or a graph of the earth's movement.

Quick Menu: Earthquakes | Measurement | Seismographs | Epicenter | Activity 1