[Meglobob]

Well I am not really certain of the exact mechanics of earthquake, I have had considerable success with 3 Troll kings casting 3 earthquakes leading armies of trolls or sea trolls. I have done this many times, resulting in no casualties for myself and destroying 1,000+ strong armies in 3 or less combat rounds. So protection, regeneration and high hps are good with earthquake. I have had similar success with MA Agartha/EA Atlantis using the massed earthquake tactic.

Earthquake is extremely effective at destroying massed mages as well, I have often taken out communions with earthquake.