Is there any study that correlates the change in movement of the earths magnetic field with the quantity, size etc. of volcanoes, or even change in land elevations?
if the solid core ‘wobbles’ and causes eddies and change in flow in the liquid core, that there should be some consequence on the surface of the earth. Reply   Volcanoes do not come from the core, but from relatively shallow depth. The core is molten and so is lava, but its density (obtained by various means, e.g. earthquake waves) is something like 10 times that of water, maybe more, as expected from iron under pressure, which also conducts electricity, as required from a source of the Earth’s magnetic field. Lavas have different compositions at different locations, but all of them are stony, they do not conduct electricity and have a density of maybe 3 times that of water. Lavas come from the crust of the Earth, where also most of the heat sources seem to be, namely, long-lived radioactive substances. Lava collects in relatively shallow reservoirs, say 50 km deep, the depth where earthquakes occur. A few sources of volcanism, so-called mantle plumes (e.g. below Hawaii) do go deep
