It doesn't so much cause a volcano as it encourages conditions for it's formation.
How?
So much for the tectonic plate, molten core theory. I guess a little hot rock from the earth’s core has no effect on heating up the water a bit. Silly me for thinking so.
Four undergrad geology classes and I never heard about that. While not an expert, I know more about rocks than the average bear.
Magma is hot enough that a few degrees of sunlight hitting the ocean floor isn’t going to make a bit of difference in whether or not it breaks through. Has more to do with pressure than temperature.