However, using suppositions aren't enough to form a solid hypothesis. They're just speculation and opinion, nothing more.
I would agree there. Though I would add that this already has a body of work behind it, and appears to be speculation that is carrying more support.
What's also quite intriging is that, from this part of the world (Eurasia), the King of Gods is often a storm God or warrior God (the latter of which YHWH clearly is). Odin, Zeus, Indra...
A more likely speculation is that YHWH is an evolution of yet another form of this King of Gods. (Much like what would happen to Zeus in later Greek religion.) But even that's just a speculation, and WAY too simple.
Again, volcanic activity may have inspired some aspects of YHWH, but chances are strong that the deity existed without volcanic activity.
I think it may be true that the deity existed beforehand, deity was nothing new, but what if the deity did became one from within the earth via volcano?
You say YHWH is a warrior God, that may be true, but that is at a tangent to this thread, which looks for belief that the original God is inspired by volcanic activity.
Like I said, this is not my theory, so supporting it or denigrating it are not my goal, but I do find it intriguing, as I have said before, and I intend to do more reading around it.
It might even drive me into reading some of the bible