Subrelluric forces in a volcanic eruption I am listening to a song about volcanoes. It is called "Pyroclastic Annihilation" performed by a brutal deth/thrash metal band called "Demolition Hammer". It is from their album "Epidemic of Violence" released in 1992. The song is:
https://www.youtube.com/watch?v=S_7qqsVioxo
the full lyrics can be found here:
https://genius.com/Demolition-hammer-pyroclastic-annihilation-lyrics

I have come across a term I do not understand.


  Molten debris
  Volcanic ash
  Seas of boiling mud
  Subrelluric forces exploding violently
  Pyroclastic matter intense velocity


Is the word "Subrelluric" a geological term? If yes what does it mean exactly? What are Subrelluric forces? What do they do amidst a volcanic eruption? I couldn't find anything on the web. Perhaps this is an extremely advance term not usually used in the public world?
This term does not exist in volcanology. I can’t even think of a similar sounding term that can be misheard in the song, or misheard by the authors and then put in the song.

It’s possible it exists in a different language but I am not familiar with any options.

Sounds like your best bet would be to ask the band.