Permalink Remember that volcano that disrupted European air traffic for a few weeks during April, 2010? Have any idea how big its magma chamber would be if it were shaped like a sphere? Volcanoes are rated on a scale called the Volcanic Explosivity Index, or VEI. The VEI scale ranges from 1 to 8, and each incremental whole number represents an explosivity of ten times the previous digit. In other words, the ash, rock, magma, ejecta of a VEI-4 volcano can be up to 10 times that of a VEI-3 volcano. VEI-4 magma chamber The Icelandic volcano, Eyjafjallajokull, having a
Original source: How Big are Volcano Magma Chambers?