This was definitely the best guess at the time, I was fully expecting to see how the Gura Gura DF could actually sink an island. Oh well, I'm sure we'll see BB do it at some point.
Anyways the erasure of God Valley is like nothing else in the series, and happened after all the big players departed. What strikes me is the sequence of events detailed in its destruction:
- Island crumbles in on itself
- Shrouded in a deep mist
- Moments of silence
- Big (regular?) lightning
It's strange that the lightning happens AFTER everything, even giving a moment of silence before exploding. Literally the only thing I can think of is Uranos being run with an inferior power source. Uranos powered by Motherflame- absolute erasure and a magic ocean hole. Uranos powered by bum juice- demolishes an island pretty bad but not absolutely and then backfires like an old Chevy Nova causing all the lightning