I remember someone in the game saying that creater was caused by a past Lunar Cry.

Oh and that thing about centra being a cross-referance to FF7, well the fact that something from space impacted there and wiped out it's inhabitants (lunar cry/meteor) is another cross reference because Jenova used meteor as transport to Earth and killed lots of cetra. Even though these are cross-references, thats all they are because if the crater in the Trabia continent is the same place as the northern crater then that's where the cetra would have lived, not Centra, there fore they are not the same world.