Plate Tectonic - Earthquakes (K)

  • Discovering that earthquakes cause different types of shaking.
  • Comparing different intensities of earthquakes.
  • earthquake
  • moderate
  • shake
  • stress
  • strong
  • weak
  • toys for building model houses
  • primary shaker tables

Students simulate an earthquake using a shaker table

San Fernando, California 1971


Earthquakes hardly ever occur one at a time. Foreshocks or smaller earthquakes which occur before the "mainshock." An "aftershock" is any earthquake that occurs after the main earthquake. The shaking people feel during an earthquake is caused by the energy released when movement is caused by a rupture in the Earth's crust or uppermost mantle. If you compare an earthquake to snapping your fingers, the rupture is the fingers snapping, but what you hear, or "feel" is the sound waves travelling through the atmosphere. The larger the energy released the larger the earthquake. Then energy moves in what we refer to as "seismic waves." Seismic waves are considered a physical wave and requires that it travels through a substance. It can be moved in many ways, but the major ways are primary (push-pull and P) waves and secondary (shear or S) waves

A wave travels through a material when a force pushes on that material and the material resists being pushed. For example, when you speak, your voice compresses a volume of air. One of the properties of air (and just about any other material) is that it resists being compressed into a smaller volume. When your voice compresses this volume of air, its resistance pushes back against neighboring volumes of air. These volumes then resist compression, and they push back against their neighbors, generating a wave of compression that travels through all the volumes of air between your mouth and the person hearing you.

Seismic waves can cause weak, moderate, or strong earthquakes.

  1. Prior to lab construct primary shaker tables. Make enough units so that the students can work in groups of 2 or 3. Here are directions:


8 long stemmed brads or nails
4 strong, thick rubber bands
cardboard box with lid
plastic container lid


  1. Cut a section from the cardboard box lid so that it will fit inside of the cardboard box as shown in the picture below.

  1. Take 4 brads and insert them from the inside of the cardboard box so that the stems fall outside of the box. Insert the remaining four brads into the cut lid of the box. Make sure that the brads are not directly on the edge as this will cause the lid to tear when it is pulled.

  1. Fasten the rubber bands to the brads inside of the cardboard box. Fasten the other ends of the rubber bands to the brads on the cut lid. Leave the lid inside of the box.
  2. Place several marbles in a container top. Put the marbles in their container under the cardboard lid in the box, to allow it to move freely when up or down.
  3. Make a small hole in one end of the box. Attach a piece of string to one end of the lid and. insert the opposite end of the string through the hole in the box. This move the lid. Don't forget to tie a knot at the end of the string where comes out of the box, this will prevent it from going back inside. Your "primary shaker table" is complete.
  1. Discuss with the class that the Earth shakes during an earthquake. Explain that shaking is caused when stress builds up on the outer portion of the Earth and it "relieves" itself.
  2. Discuss the words weak, moderate, and strong, by giving examples of familiar objects to the students. Weak refers to an earthquake that does not cause much shaking; Moderate might be when a house shakes and things might fall from shelves. Strong is when a house shakes a lot, causing many things to fall.
  3. Divide the students into groups of 2 or 3. Give each group a primary shaker table. Familiarize the students with a creating strong, moderate, and weak earthquakes. A strong quake occurs when the students pull the string all the way out; a weak one occurs when they barely pull the string a little way out; and a moderate is between a strong and a weak. Make them repeat these a few times before going on to step 5.
  4. Direct the students to build a house or town on the shaker table. Use toys that have been donated or that you have asked the children to bring from home. Do not let the students make their structures too big or the weight may prevent moving the shaker table. Instruct students to observe what happens in a weak, moderate, or strong earthquake. Make sure you explain that the students are to build the same house or town three times and observe what each type of "shake" does to the same structure. After they experiment, have them describe what happened.
  5. This exercise helps the students to understand that the Earth shakes during an earthquake, and that even houses which are "anchored" to the Earth still experience the Earth's shaking. Moreover, buildings may experience structural failure during a particular earthquake, but not during others. This is because each earthquake has its own "signature" or specific characteristics.
  6. Make sure that you do not over emphasize the damage that can occur during an earthquake; you do not want the students to become fearful. This would be a good time to discuss your school's policy during an earthquake or other disasters. If your school does not have a plan, you may wish to contact local government agencies.
  7. Discuss with students what they should do when an earthquake occurs.
    They should try and remain calm. Panic does not help a situation.
    Make a judgement of whether to stay where put or move. Many people are injured as they enter or leave buildings, but in other situations, safety is just a few steps away. The intensity of shaking and a sense of the magnitude of damage should be assessed before moving. Teach your students that each earthquake may be different, and knowledge of different responses is necessary.
    If you hear glass breaking, turn your head away from the glass.
    If outside, stay away from buildings and power lines.
    If inside take cover under a heavy table or desk.
    It is important to remember to use critical thinking skills during a disaster, whether an earthquake, volcano or weather hazard, there are certain steps one should take. In a big disaster, you have to make do with what you have available. Humans seem to get enormous strength during disasters; they tend to bond together. Disasters make people realize how insignificant lives are, when nature decides to unleash her powers. But after any crisis it is always good to say that we did all that we could before it happen. Preparedness is a skill used not only in disasters, but in every day little crisis.

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