Megadeath

Don't know why this theme keeps running through my head. I'm sure there's a reason somewhere. For those of you who don't remember, the term "megadeath" was coined during the Cold War and was a term of measurement to designate a million human deaths. Usually, experts would match nuclear weapons to a particular target and estimate the number of megadeaths that would ensue. Example: 6 hydrogen bombs dropped on Moscow = 9 megadeaths. Nice, huh?
One reason this concept has come to mind is the recent explosion in China, but as far back as Bhopal, we've been on the edge of a megadeath incident. Three Mile Island, Chernobyl, and Fukushima all demonstrate how probable such an event is, though none of them reached megadeath status.
Here's what I've been thinking about megadeath. There will be a megadeath incident in my life time. The combination of dense population and earthquake faults, super volcanos, hazardous materials, typhoons and hurricanes, tornados, or raging fires makes it almost inevitable. The one requirement for a megadeath incident is population density. As the human population grows (and it's growing exponentially), the odds for a megadeath incident increase, too.
I am most curious about how we'll respond when something like this occurs. My prediction is that, of course, we'll be horrified first and foremost. And then we'll think, "Oh, it was terrible, but it won't happen again." And we'll carry on, business as usual. But what about the second one? Or the third? What if we take the same attitude as Americans to mass shootings? We get used to them, throw up our hands and say there's just nothing to be done about it. Yeah, I think that could happen, except the US is not the world.