The VEI has some similarities to both the Richter and Mercalli scales for earthquakes with the magnitude and potential effects of volcanic eruptions being measured on a scale of 0-8.

VEI 0-2 events occur almost every year with some volcanoes showing continuous but gentle activity. Examples of VEI Events 3-8 are shown below. VEI 8 Events are so rare, the last one occured 2 million years ago.

MEASURE	0	1	2	3	4	5	6	7	8
General Description	Non-explosive	Small	Moderate	Moderate-Large	Large	Very Large	Very Large	Very Large	Very Large
Qualitative Description	Gentle	Effusive	Explosive	Severe	Violent	Terrific	Cataclysmic	Paroxysmal	Colossal
Volume of Tephra (m3)	1x104	1x105	1x106	1x107	1x108	1x109	1x1010	1x1011	1x1012
Duration of Blast (hours)	<1	1	1-6	1-6	6-12	6-12	>12	>12	>12
Cloud Column (km)	<0.1	0.1-1	1-5	5-15	15-25	>25	>25	>25	>25
Troposheric Injection	Negligible	Minor	Moderate	Substantial	Substantial	Substantial	Substantial	Substantial	Substantial
Stratospehric Injection	None	None	None	Possible	Definite	Significant	Significant	Significant	Significant
Eruption Type	Hawaiian	Hawaiian/Strombolian	Strombolian	Strombolian/Vulcanian	Vulcanian	Vulcanian/Plinian	Plinian	Ultra-Plinian	Ultra-Plinian
Interval Between Eruptions (years)	0-100	0-100	0-100	0-100	1-1,000	100-10,000	100-10,000	10,000-100,000	>100,000
Fatalities Expected	1%	3%	4%	14%	36%	39%	100%	100%	100%