How “hard” does the ground shake during an earthquake?


In this activity, students will use a three-component accelerometer (iPhone, laptop or USB) to examine their assumptions about how 'hard" the ground shakes during an earthquake.


All Audiences


65 Minutes


1.    How hard does the Earth shake during an earthquake?
2.    What does an accelerometer measure?  How can it be used to measure an earthquake?
3.    What is an earthquakes intensity? 
4.    How is an earthquakes intensity measured?

Supporting Resources


For the lesson

  • Download video footage of two-story house being tested by a simulated earthquake on a shake table at the University of California at San Diego on July 11, 2000; Kitchen/Office(5.3MB) and Child's Bedroom(4.1MB)
  • Download a recent USGS Shake Map (near-real-time maps of ground motion and shaking intensity) or this sample
  • Download a recent USGS Did You Feel It Map  (a community reported intensity map) or this sample


Internal accelerometers

  • Mac laptops only - SeisMac software
  • PC, Mac and Linux laptops - QCNLive software
  • iPhone & iTouch - iSesmometer (this is a robust and free app but others with various functionalities are available through iTunes)

External accelerometer

  • USB accelerometers (for Macs, PCs and Lunix) can be purchased from the Quake Catchers Network (request a sensor on right hand menu)
  • USB drivers and display software for PC, Mac and Linux laptops - QCNLive software

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