Tokyo and the Kanto Plain lie above the convergence of 3 tetonic plates. Luckily, only 30 million people live in that area.

A joint US-Tokyo research team recently tackled the likelihood of a severe shaking incident around Tokyo (not including the unnatural shaking from a Godzilla attack). They found a two pronged issue, offshore earthquakes and below ground quakes.

A offshore magnitude 8 quake in 1923 killed 105,000 people. The focus was on a recurrence of a large offshore quake. By dating terraces perched above the shore, they found that large offshore quakes regularly occur every 400 years. Probability (the name of the game in quake science) of an offshore in the next 30? 0.5%

But the news isn’t all good. The chance of a large quake below Tokyo in the next 30? 20%. They discovered a 25 km thick chunk broken off and stuck in between the 3 plates below Tokyo. They believe this chunk to be the source of the moderate close-in quakes. Unless the Earth starts flossing more, Tokyo will be under a threat of a large earthquake for years to come.

Want to know more? Check out Team Tokyo’s website.