As they say, $h!t happens.
A tsunami could be generated in just about any large body of water at any time; earthquakes and volcanoes are just as unpredictable and able to occur almost anywhere. Then again, it might also rain tonight, and an meteorite could crush your house, too. It's all possible.
However, I don't think any of that is a good reason to avoid getting chickens. There are plenty more immediate and important issues to consider before you get chickens (e.g. do I have enough space to keep chickens, what brooder to use, how many chickens, where will you get a coop, can I spare the time to care for them, can I afford to feed them, how will I keep them safe from predators, etc.). Also, you can transport chickens in small dog carriers just fine, and even keep them in dog crates if you had to.
Plus, if a tsunami or other great catastrophe occurred, you'd probably actually WANT to have chickens (assuming they survive the event), because then you at least have your very own source of food.