Seismograph

This “Seismograph” is an earthquake detector that records up and down motions of the ground. Stomp your foot on the floor and make a miniature earthquake. You’ll see the line jump on the computer screen when you stomp your foot.

This seismograph records the movements of the ground using a motion sensor beneath the exhibit. If you stomp farther away (or closer), you will notice that the amplitude of the spikes on the line will fall (or grow). While measuring real earthquakes, each one-number increase in the magnitude of the quake indicates a ten-fold increase in the earth’s movement, shown as a squiggle ten times as high on the seismogram.

The size of an earthquake (its magnitude) depends on the size of the fault and the amount of slip on the fault. Scientists use the seismogram recordings made on the seismographs at the surface of the earth to determine how large an earthquake is.

A short wiggly line that doesn’t wiggle very much means a small earthquake, and a long wiggly line that wiggles a lot means a large earthquake. The length of the wiggle depends on the size of the fault, and the size of the wiggle depends on the amount of slip. Scientists also talk about the intensity of shaking from an earthquake, and this varies depending on where you are during the earthquake.

Questions to Ask

What type of waves are created when an earthquake happens?

What type of wave energy is drawn by a seismograph?

Do all of the waves created by vibrations travel at the same rate? What might slow them down?

Is Earth the only place where quakes occur in the universe?

Relevant Arkansas Science Frameworks

ESS.8.3.6, ESS.9.4.1, ESS.8.6.8, ESS.8.6.10, ESS.8.6.11, ESS.8.6.12, ESS8.6.13

"Mini-Vibe" — An activity to do at home or in the classroom