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.

The Volcanic Explosivity Index or VEI is the eruption magnitude scale used to rate the eruption. The VEI considers the plume height, the volume of magma, the classification, and how often it erupts.

Here's how the largest volcanic eruptions measure up. The Volcanic Explosivity Index (VEI) ranks eruptions by size and power. The scale goes from VEI-0 to VEI-8. It measures ash, lava, and rock ...

The eruption lasted 29 hours between 9:26 a.m. Hawaiian time Wednesday through 1:49 p.m. Thursday, according to the U.S. Geological Survey. During the last eight hours, fountains shot up to 600 feet ...