Super-eruptions and super-volcanoes, but what does it all mean?

After spending a while trawling the internet and seeing some, to put it nicely, interesting articles/websites/posts, I have decided to write this post on exactly what would determine if an eruption is a 'super-eruption' and what makes a volcano a 'super-volcano'. There is much misuse of this terminology and they shouldn't be used willy nilly!

To start, 'super-eruptions'. There are two volcanic scales broadly in use today. The Volcanic Explosivity Index (VEI) created by Newhall and Self, and a Magnitude scale similar to the Richter Scale. For an eruption to be classified as super on the VEI scale it must reach VEI 8, to do this a total of >1000 km3 of material needs to be released. On the magnitude scale which uses mass of material released a magnitude of 8 or 9 constitutes a super eruption. On this scale a M9 eruption is an extremely large eruption - of which very few have occurred, only one is currently known - the Fish Canyon Tuff in Colorado of the USA.

Please note that under these scales Large-Igneous-Provinces or Flood Basalts would also be classed as 'super-eruptions' which they are not, despite their huge scale.

Simply put a 'super-volcano' is a volcano which has experienced an eruption of high enough magmnitude (M8 or 9) or VEI (8) to allow characterisation as such. A volcano which has not experienced a 'super-eruption' is (in my opinion anyway) not a 'super-volcano' and always remember, just because a volcano has had a 'super-eruption' in the past, it does not 100% mean that it will have another!  

To come soon will be a new feature, book reviews! I am going to review books in the volcanological field, starting with Clive Oppenheimers new book: Eruptions that shook the world.