E Paul Palmer investigated 'geo-fusion' which they theorized was the source of all the heat at the earth's core, which is where all the heat that melts the magma comes from.

He also called it piezo-nuclear fusion.

The earth's core is crystalline nickel and iron, and is crushed by gravity to enormous pressure.

So these elements have piezo electric properties and release an enormous amount of arcing electricity to other reverse-piezo materials. It heats up the earth's core just like a giant arc welder.