What is the main heat source responsible for driving Earth's internal geology, according to the comparison with Io?

Answer

Slow decay of radioactive isotopes within the mantle

Earth's internal heat is primarily sourced from the slow decay of radioactive isotopes within its mantle and core, whereas Io's tidal heating vastly overshadows this source.

What is the main heat source responsible for driving Earth's internal geology, according to the comparison with Io?
GeologyPlanetary SciencemoonsVolcanismIo