"occurs through the tidal friction processes: orbital and rotational energy are dissipated as heat in either the surface ocean or interior of a planet or satellite"
If this were true Mercury would have more volcanoes and geological activity than Earth, yet guess which object is hotter and has active volcanic activity? Earth. The tidal heating hypothesis is ad hoc to try and explain away Io's activity.
Think about this people. Earth has ENORMOUS amounts volcanic activity, yet is vastly further from the Sun than Mercury, but Mercury has NO VOLCANIC ACTIVITY.
Someone needs to tell these scientists that the tidal heating stuff has got to go. It is clearly false.
Io is hot because it is dissipating the energy from a past collision event. The crust is still re-adjusting and re-rounding itself via gravity from when it was shredded from a larger object, clearly many millions of years in the past before Jupiter adopted it.