User blog comment:Hyperborean/"The House of Hades" – official expectations blog/@comment-10867502-20130823184113/@comment-4503464-20130823194957

Percy's power over earthquakes is lampshaded actually kind of often in the series. But usually, he is either using Riptide to make massive crevices and such, not his own power (or at least, I think so). But yeah, totally unconfirmed.