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Experts say M9 Nankai Trough earthquake would kill hundreds of thousands

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posted on Aug, 30 2012 @ 05:58 AM

An offshore Pacific earthquake of the scale that hit Japan last year would trigger 34-meter tsunami, resulting in at least 323,000 deaths and devastating much of the coastline from Honshu to Kyushu, experts say.

This grim scenario is the result of a radical reappraisal of a possible magnitude-9.1 earthquake in the Nankai Trough in light of the Great East Japan Earthquake that left 20,000 people dead or missing.

Much more at link!

As many here will know, I have had major concerns that stress redistributions to the south from the epicenter area of the big M9 in 2011 could possibly trigger another big quake on the southern triple junction. I did two threads on the issue, but fortunately for Tokyo, this massive quake has so far not occurred.

Two expert panels were commissioned by the government to offer a realistic assessment of what Japan can expect if a Nankai Trough earthquake strikes.

At the same time, the panels cautioned that the possibility of such a major disaster occurring was low. However, they called on the public to be "properly fearful" of what may lie ahead.

It is a given that the reappraisal will force the central and local governments to go back to the drawing board in assessing their disaster management plans.

I can't see how they are saying the possibility is "low". Not when they KNOW that stress redistributions will likely eventually trigger this quake, not to mention scientists have been expecting a big quake there for years. And also not mentioned is the likely effect this reassessment will have on earthquake insurance rates.

The worst-case scenario was based on a premise of a magnitude-9.1 quake striking.

Under the scenario, 151 municipalities in 10 prefectures, ranging from Shizuoka to Miyazaki in Kyushu, would experience shaking of a maximum 7 on the Japanese intensity scale and 239 municipalities in 21 prefectures would experience shaking of upper 6 intensity.

It said tsunami of at least 20 meters would strike eight prefectures, including the islands of the Izu and Ogasawara chains that are under the jurisdiction of the Tokyo metropolitan government.

I find it interesting that previously the worst case scenario was thought to be around a 7.5 for the area where what happened was a 9+. So now they are saying a 9.1 as a worst case, when in fact it could possibly break all earthquake records ever, and be higher in mag than the massive 1960 Chile quake (biggest on record)?

In the estimate for extensive damage in the Tokai region late at night in winter when winds are strong, total fatalities would reach 323,000.

Of that figure, 230,000 people would die in tsunami, 82,000 from collapsed buildings and 11,000 from fires caused by the quake. The number of injured people was put at 600,000.

Between 2.364 million and 2.386 million buildings would be swept away or burned to the ground due to the shaking, tsunami, fires as well as collapse of foundations brought about by liquefaction.

As a result, the panel estimated that 311,000 people would be trapped under the rubble of collapsed buildings and would have difficulties digging themselves out.

That is another staggering figure considering the fact that there are only 160,000 firefighters in all of Japan.

The Great Kanto quake underscores the potential of this event. The question is if there has been enough accumulated stress in the fault to really cause this anytime soon... Scientists are just starting to get a grip on the unpredictable recurrence rates of big quakes in all the thrust faults around the world.

posted on Aug, 30 2012 @ 06:29 AM
reply to post by TrueAmerican

The appraisal said the Hamaoka nuclear power plant in Omaezaki, Shizuoka Prefecture, would be under nine meters of water if work to build an 18-meter-high breakwater wall and higher embankment walls is not taken into account. The work is expected to be completed in December. The plant stopped operations in May 2011, two months after the Great East Japan Earthquake, at the request of Prime Minister Naoto Kan because it lies within the epicenter of a predicted major quake. The maximum tsunami height in Omaezaki was put at 19 meters. Chubu Electric Power Co., which operates the Hamaoka plant, has installed water-proof doors for the reactors and moved emergency generators to elevated ground 40 meters above sea level.

Op source

I see they are at least attempting to learn from and respond to the tsunami threat I wonder if any of the plants on the US west coast or other areas at risk of tsunami have also taken further protective measures?

posted on Aug, 30 2012 @ 07:48 AM
reply to post by iforget

I think they need to build in extra height for the unanticipated. I mean over engineer that wall for an extra 10 meters!

And what I am talking about is this:

Look at the size of that wall and that water overcame it in no time!

As to the west coast USA nuclear power plants, that might be a bit off topic- cause we are talking about Japan in this thread- and that has been covered in many other posts around ATS.

posted on Aug, 30 2012 @ 08:12 AM
reply to post by TrueAmerican

Brilliant work again TA, many thanks.

As way of a little explanation, when they say "low risk" i would take this to mean that they accept it will happen but have to take into account geological time scales. So whilst it will almost certainly happen at some point, for the purpose of risk assessment they have to take into account geological time scales (all comes down to money, everything has to balance unfortunately). I would almost certainly wager that whilst the report says that, any local experts involved may well be moving away from the sea to a more lofty location!

posted on Sep, 2 2012 @ 06:38 AM
reply to post by TrueAmerican

Unbelievable what water masses can do.

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