I'm more radical. I would collapse all the buildings with a earthquake (the characters inside of buildings would be "pushed" outside, with some damage of course. But just the characters). Then, at the same time, I would destroy all outside machines and docked ships with tsunamis (into the sea-coast) and tornadoes (into the locations inland), that also would "move" characters to different places (again, with some damage). Who would be the lucky ones? Those who where sailing at the time of the disaster.
We would have to start again in some kind of "Mad Max" scenario (just land-vehicles and the few ships that would be occupied and into the sea at the moment). But don't worry, don't panic, I know this would never happen

