NOVA Online (click here for NOVA home)
Deadly Shadow of Vesuvius
Site Map

Eruption The World's Deadliest Volcanoes
See a slide show of the worst volcanic disasters in history and learn what caused the casualties.

How do you measure the size of a volcanic eruption?

Just as seismologists measure the size of an earthquake using the Richter scale, volcanologists use an eruption magnitude scale called the Volcanic Explosivity Index, or VEI to classify eruptions. This scale assigns a number to an eruption based on things that can be observed, such as the height of an eruptive plume and the volume of the materials erupted.

Ready to rate the eruption you're watching? Here's what to do:

First, check out the Volcanic Explosivity Index (VEI) chart.



Photos: Gary Rosenquist

SWAT Team | Predict Eruptions? | Deadliest Volcanoes
Planning for Disaster | Resources | Teacher's Guide
Transcript | Printable page | Site Map | Vesuvius Home


Editor's Picks | Previous Sites | Join Us/E-mail | TV/Web Schedule
About NOVA | Teachers | Site Map | Shop | Jobs | Search | To print
PBS Online | NOVA Online | WGBH

© | Updated November 2000