What disaster are you imagining that takes out an underwater colony? It'd be completely sealed off from the water, so you could vaporize the entire ocean (unli

What disaster are you imagining that takes out an underwater colony? It'd be completely sealed off from the water, so you could vaporize the entire ocean (unlikely) and atmosphere and it would still be okay. The only thing I could see affecting an underwater colony would be an earthquake, but I'm having trouble imagining an earthquake big enough to wipe out all surface life.