Eastern Japan to Brace for Another M9 Earthquake Within 30 years

Ryo Mac
Skeptikai
Published in
3 min readJan 2, 2012

Japanese scientists are revising their earthquake prediction levels because of new information that has been analyzed since the Great Eastern-Japan Earthquake, according to the Asahi Shimbun. I haven’t seen this discussed by any English media outlets, so I’m just going to translate the main parts of that article. Basically, taken in the context of earthquakes in Japan as a whole, it means that the next 30 years are probably going to be pretty rough on Japan.

The Eastern Japan coast — the one that received the beating in March — is now looking at another massive earthquake of the same magnitude. You can use the map above to help you understand some of the names of places or follow along with the numbers that denote the magnitude.

This is what they said at Asahi:

Japanese scientists at the Headquarters for Earthquake Research Promotion (HERP) have made a review of the probability of a massive earthquake occuring again in Japan in the near future.

Earthquakes such as those in 1611 off the coast of Sanriku, in 1677 off the Bousou Peninsula, and in 1896 from the Meiji-Sanriku quake, resulted in massive tsunamis that levelled coastal towns and cities. The scale of potential tsunamis and earthquakes was calculated based on the data gathered from such incidents.

It was previously thought that there was basically a 0% chance of a near-M8 earthquake in the outer region off the coast of Miyagi within the next three decades. However, the recent seismic activity from March 11 has given scientists new data that brings that number up to 50%.

Other dangerous areas include Iwate, which has a 90% chance of getting an M7.6 quake a few hundred kilometers away, and Ibaraki which has a 70% chance of getting an M7.7 considerably close to shore.

Also quite concerning is the 30% chance of a M8.6-M9 earthquake to hit somewhere off the East coast, sometime within the next 30 years.

These conclusions are based on the available information, and are subject to change as more knowledge is acquired and more research is done.

The worst part about this news is that it has nothing to do with the recently announced 70% chance of a big earthquake to hit in or around Tokyo within the next 30 years. I can’t imagine which one would be worse; a repeat of what we got in March, or a tsunami-less earthquake near or in Tokyo. A tsunami is usually more deadly than an earthquake, but Tokyo is the most populated city in the world. With around 30 million people living there, it would really be a battle of Japanese science against one of the most unpredictably devastating forces of nature; the stakes of which are so high that most of the interviews I have heard since March regarding a Tokyo quake end with “…but hopefully we won’t have to find out.”

So basically, the next few decades will be plagued with uncertainty for those of us who live here in Japan. But then… that’s really nothing new about that.

And to any one of those apparent psychics who say they’re brilliant for predicting an earthquake in Japan: You’re not impressive. Not only is Japan one of the most seismically active places in the world, but the recent earthquakes make it even more likely for more to be triggered, such as yesterday’s M7 earthquake under Tokyo. Unfortunately, another big earthquake is almost certainly going to happen — it’s just a matter of when and where.

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