User blog comment:Jabberwokk/The Romans/@comment-3459279-20110913175701/@comment-3146930-20110913205842

On the other hand, there really isnt a god that controls dirt. I mean Gaea controls the Earth. Poseidon can cause earthquakes, but he isnt really an "earth" god. I dont believe children of Hades can control the earth. Both times Nico showed that power, it was related to the Underworld. When he opens the ground, he created a portal to the Underworld so maybe the portal opened the earth. When he used it again to save Percy from Kronos, he created collumns of "black rock," as in Erebus, the black walls of the underworld