The Mysteries of Vana 'Diel

[Sparthos]

It was an explosion near Qufim Island, I don't recall what exactly, but it blew up a large chunk of the land in Batallia, Sauromogue, and Qufim Island.

I believe it had something to do with Sky and the Cermet spines. the Blast originated from close to Delkfutts (Hint though: Im betting Qufim wasn't always a "Crescent shaped" island, go check the coast lines by Delkfutt/etc, They're charred black like the ones in Bat/Saur because of the explosion)

The Zilart were trying to revert Vana'diel back to paradise, the Kuluu sabotaged the plan which caused the meltdown that drastically changed some environments and scarred the land.

Al'taieu seems to be the "missing" part of Qufim Island as Bahamut rises from the Shu'meyo Sea at the beginning of CoP. The palace defense mechanism that shifted the whole palace into the Al'taieu crystal was also the device holding off the Wyrmking at the time.