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Last time I was in Japan there was a 5.8 earthquake in Tokyo bay (between central Tokyo and Yokohama). I've felt this sort of earthquake three times, I think the first time was outside and the others were in the morning. It feels like there's someone under your bed and kicking it. Bumpy, but nothing to be afraid of. Still it really makes you wish that it stops soon and doesn't get stronger. There are apps that send you a warning whenever a strong earthquake occurs, but of course there's nothing much you can do if shit's going down.
The Great Hanshin earthquake in 1995 was 7 MMS and 2011 Tōhoku earthquake was 9 MMS. Having only experienced earthquakes less than 6 MMS it's absolutely terrifying to try to imagine how tremendously powerful that sort of huge destructive earthquakes are... I really recommend everyone to visit Kobe's earthquake museum. One of the best science/memorial museums I've ever visited.