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Comment by Shivetya | Hacker News Reader

The concern some have is that this earthquake could simply be the lead in for the larger one to follow similar to the Tohoku quake

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There have been 9 earthquakes in this region of magnitude >= 7.0 since 2011, including the 9.1 Tohoku quake. Of the remaining magnitude >= 7 quakes, 5 were in 2011, 1 was in 2012, and 1 in 2013, and finally the newest one yesterday.

Source:

https://earthquake.usgs.gov/earthquakes/map/?extent=16.46769...

That's helpful information. It doesn't invalidate the concern, however, since very large earthquakes are often preceded by moderately large foreshocks, so there is an now a temporarily elevated risk of a very large earthquake in that region.

In the list you can see a foreshock happening two days before 9.1 earthquake (Tohoku). Then after that you have a couple of years of aftershocks. Obviously this is not a guarantee "big one" is coming but it's probably good idea to check contingency plans.

I was in a tenth-floor restaurant in central Tokyo during that March 9, 2011, earthquake, two days before the big one. The shaking last night, which I felt at my home in Yokohama, was reminiscent: not terribly strong, but lasting a long time.

Last night, it was long enough for me to sit up in bed, wait for a while, get up, stand in the living room for a while, and then go upstairs to where my daughter and one-year-old grandson were sleeping, with the shaking and rattling continuing the whole time. After it stopped, we all went back to bed.

In 2011, I happened to leave Yokohama for Osaka by train on the morning of March 11 and missed the big one by just a few hours. I'm hoping to be away when the next big one hits, too.

This one is being called an aftershock of the 2011 large earthquake. Not sure if that makes much difference in what happens next, though...

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