What occurrence could completely submerge a city- let's say Los Angeles- relatively quickly without actually causing a great deal of damage to it in the initial process? (A little like Atlantis. But in Los Angeles. Los Atlantageles.
This would be in modern times, or the very close future (within the next few decades). Something somewhat scientific would be preferable, though if it floods LA and makes sense- then it's fine.
For example, I was initially thinking about things like global warming, and the ice caps melting. But this process seems far too slow- as the sea levels wouldn't jump a metre overnight.
I'm out of ideas. It's worth pointing out that LA would need to be permanently (or at least for a very long time) submerged. This is why I'm stuck. So either the entire ocean rises, or California sinks.