Most mainstream media movies have downplayed that aspect of Poseidon's divine portfolio but it is rather evident in the classic literature and mythology, which I tend to favor over the often-awful Greek cultural-inspired movies.<br/><br/>And when in doubt, we should go to the PJ books as it is the source of our setting.  Percy used earthquakes in the books and Poseidon is mentioned as having dominion over that power in there as well.<br/><br/>..the original "Clash of the Titans" is campy-awesome though.