This isn't the first video of its kind I've seen. The tsunami uprooted all kinds of junk, including items containing compressed or trapped gasses. This is just one of many plumes of mist/smoke/whatever in an entire sea of what used to be a city.
Add wishful thinking to artifact-cluttered video and suddenly GHOSTS!
My vote is: faked. It looks like someone used some kind of blur tool on the frames to produce the result. At higher def in slow motion it looks like static pixels just being moved around by some post production process.
Great premise for a story or something, but I don't think it's something that was actually captured on the video. Call me extra skeptical.