If I remember right. The largest eruption in the 20 century was Nova Erupta (SIC) in Alaska.
I am not going to do searches on the dam thing. Just what I remember with discussions with the geologist professors I used to know.
These guys chomp at the bit to get on one after its safe after an eruption to study minerals those things bring up.
On further reflection per my reply to you about Nova Erupta.
Do you know what happened in Nov the next year on the Great Lakes?
The largest, most nasty storm ever recorded. Killed over 270 sailors and sunk quite a few ships.
A result of that eruption IMO.