 Well, something. We know that subsea volcanoes cause thermal currents and sometimes ash and steam to come to the surface and create new islands. We know the oceanic ridges are the source of the new magma coming up. But I would think that on a worldwide basis, 70% of the world is water. That's right. And miles deep, that it would be hard to see what's happening with the crust below over broad areas, not just over volcanic vents.