How can you model earthquakes in the classroom?

Earthquake Machine- Block & Sandpaper

  • For background on this animation series, download Background from the Resources box.

  • Animations are available for preview in embedded YouTube.

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Blocks EQ Machine Basic

On the graph, the yellow line shows the movement of the hand over time, thus a steady line. The blue line shows the movement of the block during slip on "earthquakes" thus the jumps in distance over time.

Quicktime (514 kB)

Blocks Slow Slip Time / Strain

This animation shows the "Earthquake Machine" using two blocks with different grit sandpaper, thus different friction. Animation illustrates the build up and release of strain in locked and slow slip zones. The first block, in red, has fine sandpaper on its bottom and simulates the slow slip zone between tectonic plates. The second block with coarse sandpaper on its bottom side, simulates the locked zone of two plates. As the first rubber band is slowly pulled, strain builds up. Once enough energy is stored in the rubber band to overcome the friction of the sandpaper under the red block, the red block slips slightly. (Note: This is similar to the slow earthquakes or episodic tremor and slip events in the Pacific Northwest.) Once the red block slips, the rubber band between the red and blue wood block stretches slightly. As this rubber band continues to stretch, the strain between the blocks builds until the blue block finally moves. The movement of the blue block would be equivalent to a major earthquake.

The yellow line plots the steady displacement of the hand. The red line shows the strain on the rubber band between the hand and the red block. The strain drops suddenly to a lower level each time the red block slips (earthquake slip). There is low friction between the red block and the surface, so "earthquakes" tend to be more frequent and smaller. The blue line shows the strain on the rubber band between the blocks. The blue block has higher friction with the surface, so it tends to slip in larger "earthquakes."

Quicktime (1.4 MB)

Blocks Slow Slip Time / Distance

This animation shows the change in distance over time. Observe that the red line steps up in small increments, while the blue line has large sudden movements, similar to the large movement expected during a catastrophic earthquake along a subduction zone. The change in strain over time is illustrated in Blocks Slow Slip Time / Strain. Observe that the strain in the red line constantly builds and is then released, while in the blue line, the strain builds in sudden steps until a catastrophic release of energy occurs.

Quicktime (1.4 MB)

Elastic Rebound

Quicktime (900 kB)

Single Block Model

Quicktime (1.75 MB)

Two Block Model

Quicktime (1.84 MB)

Animations and videos are made in partnership with Earthscope, USGS, and Volcano Video & Graphics.

Please send feedback to Jenda Johnson.