What is the Volcanic Explosivity Index (VEI)?

What is the scale used to measure volcanic eruptions?

  • Volcanoes have a similar scale called the Volcanic Explosivity Index (VEI). The scale was invented by Chris Newhall of the U.S. Geological Survey and Stephen Self of the University of Hawaii in 1982. The Volcanic Explosivity Index gives us a way to measure the relative explosiveness of volcanic eruptions.

How do you determine the explosivity of a volcano?

  • (Public domain.) Volume of products, eruption cloud height, and qualitative observations (using terms ranging from "gentle" to "mega-colossal") are used to determine the explosivity value. The scale is open-ended with the largest volcanic eruptions in history (supereruptions) given magnitude 8.

What does an eruption with an index of 1 mean?

  • The scale is logarithmic, or based on 10; therefore, an increase of “1” on the scale indicates an eruption 10 times more powerful than the number before it on the scale. Look at some examples in the Volcanic Explosivity Index table that follows. A volcano classified with an index rating of "1".

image-What is the Volcanic Explosivity Index (VEI)?
image-What is the Volcanic Explosivity Index (VEI)?
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