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.
Thought I would share an image of a super-volcano in our own back yard. Glencoe is thought to be the site of a massive piece-meal caldera collapse brought on by a VEI 8 eruption. The image below shows two of the three sisters which are formations of ignimbrite. Ignimbrites are formed when ash and other various tephra from a pyroclastic density current weld to form a rock, they are often signs of very large eruptions. They can also be seen in the Scafell area of the Lake District in the UK and in areas such as Yellowstone, USA.