Measure a Changing Volcano


This hands-on demonstration illustrates how GPS can be used to measure the inflation and deflation of a volcano. Volcanoes may inflate when magma rises closer to the surface and deflate when the pressure dissipates or after an eruption.

Measure a Changing Volcano Demonstration (Acrobat (PDF) 645kB May22 18)

Video of the demonstration: YouTube or MP4 Video (MP4 Video 33.9MB May23 18)


This can be used as in class exercise with upper elementary to high school students. It also makes a great interactive outreach demonstration.

Teaching Notes

  • Although you can use flour, corn starch, or drywall powder, these substances have more allergy and irritant potential. Thus sand is generally preferable.
  • Balloon pumps to inflate the balloon (i.e. magma) are definitely preferable for public events where the presenter may need to do the demonstration multiple times. However, they are not as necessary for classrooms where the inflation may only be done once or twice.
  • The "Junior Scientist" activity booklet.pdf (Acrobat (PDF) 438kB Jun15 18) can be printed and used to record the distance between stations as well as general observations.

Reference Information

Author/Developer: EarthScope Consortium

EarthScope Consortium logo. Concentric circles in red grading to purple.