Seriously, though, one does wonder what, if anything at all, causes the rise of magma, or hotter regions of magma to directly under thin regions of the crust, where the resultant effect is volcanic activity. Is it due to electromagnetism? Convection currents? Flux of solar radiation? ALL of the above? Yes, one does wonder. But one seems to make little effort to find out.
When I enter your phrase "rise of magma" on Google, I get 282 hits, including this.
It's astonishing what you can learn if you actually go look around.
While searching the internet for information is a wonderful time consuming feature, I also like to participate in discussion and conjecture. Sometimes someone actually knows much about a subject (like you) and can quickly boil the total of their knowledge down to a few sentences and enlighten an astonished group of FR readers.
I am not demanding you spend all your time educating me, but I find FR a very good place to acquire knowledge.
How about if every time you asked a question on FR, everyone told you to go find the answer yourself, using the search facility? Might tend to make you think it was an unfriendly place, occupied by self-absorbed intellectuals without social skills or common courtesy?
I appreciate the links and will spend time researching this more, as I love to learn.
But, I also like to discuss. I hope you don't mind too much. You have been so helpful, and quite polite, and I do appreciate it.
P.S. The link to 'this', was interesting, but did not explain why at all. It simply referred to this study being an aid to attempts to figure this out. The title looked promising, but failed in the delivery.