Does the second half of this aspect, the bonus to Earthquakes, are constant, and not dependent on getting a Overpower hit?
Sounds like it is, but has it been confirmed?
Thank you
Correct the damage increase to your EQs is not dependent on Overpowering.
This is just like how Bul-Kathos and Earthquakes do not only give their bonuses when you proc an EQ by Leap or Ground Stomp. As long as you are able to proc an EQ by any means, you gain all effects and combinative damage.
It is written very poorly and wonky that the ability to generate EQs is not inherent into the Skill Tree.