Not to fear monger but this is something that I’ve kept my eye on for a long time.
The Tokai Earthquake
https://www.thoughtco.com/the-tokai-earthquake-of-20xx-1440533
It’s a speculative mega earthquake that occurs once every 100 or so years.
https://en.m.wikipedia.org/wiki/Tōkai_earthquakes
This area includes all of the major urban centers of Japan including Tokyo, Osaka, Kobe, Nagoya, and Kyoto. In the past, it occurred in 1498, 1605, 1707, and 1854. These earthquakes measured between a 7 or an 8. In comparison, this Hokkaido earthquake was a high 6. Osaka back in July was a 5. Kumamoto in 2016 was a double with a 6 and then a 7 the next day. The Tohoku Earthquake in 2011 was a 9 and the strongest ever in Japan. And the Kobe earthquake in 1995 was also a high 6. Japan goes by Shindo scale which measures an earthquake based on how much things shake on the surface rather than the energy released within the earth as used by Mw scale.
In some cases, things like fires, landslides, and tsunamis cause more damage and death than the actual earthquake. That’s one reason why Japan really focuses on earthquake prevention technology and minimazling damage as much as possible. Especially since the Olympics are just around the corner. Previous Tokai Earthquakes caused tons of damage and 20,000+ deaths. But that was like in the 16-1700’s which obviously didn’t have today’s earthquake protection technology.
A lot of resources have been poured into earthquake prediction (though black magic has been ruled out) and how it minimalizd damage. Still, no one is sure when or if it will strike within the near future. But it’s something people watch out for and earthquakes such like this tends to rattle the Doomsday cage.
Sorry to continue the earthquake discussion but seeing as how the Smash community has focused on it; I thought I would contribute some info to the topic outside of what happened in Hokkaido.