I suspect it has something to do with the concept "magma chamber", as if there is a big, singular hole underneath each volcano, rather than a loose network of m

I suspect it has something to do with the concept "magma chamber", as if there is a big, singular hole underneath each volcano, rather than a loose network of multiple layers of melted & semi-melted rock spread over tens of kilometers of crust depth, organized by geological strata, which periodically melts through an obstruction or solidifies into an obstruction.