How could you calculate the energy of a volcano?

[Ax_xiom]

TL;DR

Finding what method people use to calculate the energy of volcanic eruptions

So how can I calculate the energy of a volcanic eruption? If I know the VEI, total ejecta, duration and plume height would that be enough or would I need more variables?

 

[Baluncore]

So how can I calculate the energy of a volcanic eruption?

If you can explain why you want to calculate the energy of a volcanic eruption, then the variables you must include, will become obvious.

 

[Bystander]

TL;DR Summary: Finding what method people use to calculate the energy of volcanic eruptions

So how can I calculate the energy of a volcanic eruption?

"Tambora/Yellowstone." or Mt. St. Helen's/Paracutin? "The Lighthouse of the Mediterranean," perhaps?

 

[Ax_xiom]

"Tambora/Yellowstone." or Mt. St. Helen's/Paracutin? "The Lighthouse of the Mediterranean," perhaps?

More Mt Tambora but I would like to know the methods used to calculate energies for all eruptions

 

[Ax_xiom]

If you can explain why you want to calculate the energy of a volcanic eruption, then the variables you must include, will become obvious.

I want to compare the energy output of volcanic eruptions to nuclear bombs and other natural disasters. I'm assuming that the amount of ejecta would be the main variable, with stuff like duration, plume height and type of lava would be secondary variables

 

[tech99]

I suppose the number of times the shock wave travels round the earth would be a guide to the energy.

 

[Ax_xiom]

After a bit of research I think that what people actually do to calculate the energy release of a volcano is to look at the shockwave and then use it to calculate the energy (like you would do with an explosion). An example is here where they compared Hunga Tonga to Tsar Bomba and Mt St Helens. Although most sources don't show how they did the maths to arrive at the numbers they did :(

 

[Baluncore]

I want to compare the energy output of volcanic eruptions to nuclear bombs and other natural disasters.

I don't think they can be compared on a one dimensional scale.
For a start, Hawaiian type volcanoes do not explode. Those volcanoes that do explode, push a lot of mineral dust, gas and water up into the stratosphere.

A nuclear bomb would knock over a city, then burn it in a firestorm, convecting the combustion products, up into the stratosphere.

The destruction of a meteorite in the Earth's atmosphere is similar, in that it first generates a shockwave, then a strong wind, driven by convection of the heated air column. Bigger body impact events, will behave like an explosive volcano.

So, how to measure the magnitude of the event? A shock wave is hard to monitor, even during a predicted event. The total mass of surface material entering the stratosphere would be one metric. It could be assessed by the later fallout of sediment onto snowfields, glaciers and icecaps.