Fukushima: Should they have known? Historic Quake Analysis

I will offer you information as I have determined it, and what I say is not intended as either a vindication or a castigation of the TEPCO company, or the designers of the plant. My interest is purely based on my curiosity........

Should they have known? Should they have built the plant to withstand a stronger earthquake?

Simultaneous seismic activity along the three tectonic plates in the sea east of the plants--the epicenter of Friday's quake--wouldn't surpass 7.9, according to the company's presentation.

Source

Magnitude 7.9 or or 8.0 or around that seems to be the general consensus of the level of earthquake that the plant was built to withstand. There are many people with perfect 20/20 hindsight saying this was not enough. Are they right?

The area of interest for me is encompassed in the following areas

Lat 35°N to Lat 37°N and Lon 139°E to 145°E
Lat 37°N to Lat 40°N and Lon 140°E to 146°E

This forms 2 rectangular areas that cover the Honshu coastline from Tokyo to the North of the island

Because of the uncertainty of data earlier in the last century prior to around 1960 or so the data I will present is in two parts.

First part is 1900 to 1961, Magnitude 6+ earthquake energy.

Construction for the Fukushima Nuclear Power Plant started the 25th of July, 1967.
The plant was built by Kajima Construction Corporation, Ltd.
This is a Japanese construction company. Founded in 1840.

Fukushima I was fully operational in the year 1971.

Source

Basically this graph covers the period prior to the commencement of the construction and is very relevant.

So what does this graph show? Each spike is the cumulative energy for that year. Obviously the largest spike was 1933, so what happened that year? In terms of numbers not so much

1933-03-02T17:31:00.920Z 39.22 144.622 8.4
1933-04-09T02:46:42.380Z 39.39 143.658 6.8
1933-06-18T21:37:37.730Z 38.28 142.51 7.2
1933-07-20T23:14:00.410Z 38.69 144.861 6.8

The 8.4 in March 1933 was 8.4 Mw or 8.5 Ms and therefore exceeds the design capacity of the plant. Whilst arguably that is good reason to have deigned the plant to higher levels of resistance I actually doubt if there are any buildings anywhere in the world that have been designed beyond this standard. The reasons are this:

First very few buildings are found immediately in the zones where magnitude 8+ earthquakes have occurred historically. These earthquakes rarely if ever occur on land.

Second mega earthquakes of 8.5 and above are relatively infrequent.

Thirdly the energy difference between a magnitude 8 and a magnitude 8.5, which is 5.6 times stronger than a mag 8, is 291,718 Terajoules of energy At mag 8 your building is designed to withstand a blast of 15.1 Megatons of TNT (About 1000 Hiroshima bombs) [Not directly of course]

To take it to magnitude 8.5 it must withstand 84.8 megatons of TNT or about 5600 Hiroshima bombs.

That 8.4 in 1933 was located here

[atsimg]http://files.abovetopsecret.com/images/member/929aa8b234b0.png[/atsimg]

In many ways since the data above covers the time before construction of the plant the story sort of ends there. Whether you consider that they should have designed something stronger, bearing in mind that 1933 was the ONLY mag 8, despite the obvious question of whether or not it would be possible, is up to you.

Before closing however I would like to point out two obvious facts.

(1) There have been no magnitude 8 earthquakes in that area since until....

(2) Even if they had built to 8.5 standards, what is the difference with a 9.1 Mw as it is now classified?

Here is the data from 1962 to Feb 2011

[atsimg]http://files.abovetopsecret.com/images/member/44295cded88d.png[/atsimg]

The seismicity in this period is fairly stable and well inside the built for limits. Those who say, and some do, that they should have allowed for a mag 9 actually have no notion whatsoever of what they are saying. See now the same graph extended into 2011 to the end of August.



A 9.1 Mw is a completely mind boggling difference from the design limit mag 8

The energy difference between 8 and 8.5 is bad enough

[atsimg]http://files.abovetopsecret.com/images/member/b6e1f069a8f4.png[/atsimg]

Now look at a 9.1

[atsimg]http://files.abovetopsecret.com/images/member/0cdff7c432e9.png[/atsimg]

That is 44,668 Hiroshima bombs of difference.

Personally I question the wisdom of building any nuclear plant on a subduction zone, whether you expect a magnitude 8.0 or not.

As to whether they basically miscalculated here? Over to you....

Data is either from the USGS Centennial Catalogue or downloaded from the ANSS web site

Originally posted by PuterMan
In many ways since the data above covers the time before construction of the plant the story sort of ends there.

I have no idea what you mean by that. They knew a large earthquake was possible in the same area since it had happened before.

While there was apparently some damage to the Fukushima plants from the earthquake, your analysis seems to have failed to consider if this should have been the case. Specifically, what was the strength of the shaking at the location of the nuclear plants, which would be less than at the epicenter? That is covered in this report:

www.tepco.co.jp...

In summary it appears to have partially exceeded the design conditions, resulting in some limited damage..

However, it's not clear to me that the damage would have been catastrophic from just the earthquake. It seems like the bigger problem, was the tsunami and the lack of preparedness for such a large tsunami.

Had they built backup generators at the top of indestructible towers that wouldn't have been flooded by the tsunami, there likely wouldn't have been multiple meltdowns, since the primary reason for the meltdowns was loss of cooling and not the earthquake damage.

Whether you consider that they should have designed something stronger, bearing in mind that 1933 was the ONLY mag 8, despite the obvious question of whether or not it would be possible, is up to you.

Designing the reactor to withstand an 8.0 level of shaking at he facility (rather than offshore) probably would have been adequate, not to prevent all damage, but to prevent meltdowns.

I'm much more concerned about backup/emergency power availability after a large tsunami. It seems that's where their design failed the worst. A large tsunami could originate anywhere in the Pacific, even as far away as the pacific NW of the US, so they can't be so short-sighted to just look immediately off the Japan coast for sources of a potential tsunami. They needed to be better prepared for that.

Also, that reactor design used in the failed plants had a pretty weak containment as reactors go. It was known it didn't take much to breach containment, even without an earthquake. So that was the next largest design flaw after the lack of tsunami preparedness. The earthquake design limit was further down on my list of largest problems with the design.

reply to post by Arbitrageur

I have no idea what you mean by that. They knew a large earthquake was possible in the same area since it had happened before.

Precisely, and the phase meant that MY story ends there at the 1962 point since there is evidence of a prior large earthquake that exceeded the design specification of the plant, even though that event was some distance away.

While there was apparently some damage to the Fukushima plants from the earthquake, your analysis seems to have failed to consider if this should have been the case. Specifically, what was the strength of the shaking at the location of the nuclear plants, which would be less than at the epicenter?

There was indeed some damage from the earthquake, but not as much as the damage from the resulting tsunami. My analysis does not fail to consider anything since my intention was to analyse whether the selection of magnitude 8.0 was a reasonable design criteria based upon historical activity. As you rightly point out there was damage, and I would say that since the earthquake was something of the order of 44 times as powerful the fact that the structure stood is a testimony after the event that the construction was reasonably sound. Would it have stood a direct hit from a magnitude 8, i.e. being much closer to the epicentre? No I doubt it.

I am not able to determine the shaking exactly since I do not have access to the instrumentation but you will find a wealth of information concerning the effects of the earthquake on this site: GEO's Tohoku-oki Event Supersite Website

You can see some animations of the forces at play here

Designing the reactor to withstand an 8.0 level of shaking at he facility (rather than offshore) probably would have been adequate, not to prevent all damage, but to prevent meltdowns.

I'm much more concerned about backup/emergency power availability after a large tsunami. It seems that's where their design failed the worst. A large tsunami could originate anywhere in the Pacific, even as far away as the pacific NW of the US, so they can't be so short-sighted to just look immediately off the Japan coast for sources of a potential tsunami. They needed to be better prepared for that.

My purpose was not to consider the construction of the plant with regard to tsunamis, although one would assume that when building for a magnitude 8 they were also building for a sizeable tsunami, and of course Japanese gave us the word tsunami. Japan has had some very large tsunamis in the past and the Tohuku resultant tsunami was not by any means the largest. In that respect they failed miserably.

A magnitude 8.4 earthquake caused sea waves as high as 25 m to hammer into the Pacific coasts of Kyushyu, Shikoku and Honshin. Osaka was also damaged. A total of nearly 30,000 buildings were damaged in the affected regions and about 30,000 people were killed. It was reported that roughly a dozen large waves were counted between 3 pm and 4 pm, some of them extending several kilometres inland at Kochi.

Source: The 10 most destructive tsunamis in history

Aside from the obvious stupidity of building it where they did, on a subduction zone prone to large earthquakes my feeling is that as far as the strength of the building to withstand earthquakes is concerned, which was what I set out to determine, the building was in my opinion marginally adequate based on the fact that most large quakes of this nature are offshore. People say they should have allowed for a magnitude 9. I say they could not. This was an exceptional event with no known precedent in Japanese history.

As far as the preparedness for the resulting tsunami is concerned that is entirely another matter and my own opinion is not simply that they could have done better but that is this area there was a complete failure to anticipate an event that historically in Japan had happened many time before. That lack in the design borders on criminal, no in fact was criminal, but that was not what I was looking at.

Originally posted by PuterMan
People say they should have allowed for a magnitude 9. I say they could not. This was an exceptional event with no known precedent in Japanese history.

Thanks for the clarification. I agree with most of what you said, with the exception of this quoted interpretation of your previous statement there had been an 8.4 in 1933.

I think if you asked 10 geologists if an 8.4 quake occurs in a location, what are the odds a 9.0 could occur at the same location within the next century, 9 out of 10 would say it's possible. While a 9.0 has more energy than an 8.4 as you rightly point out, they are both relatively large quakes and the magnitude is rarely exactly the same so the next big one could be more or less powerful than the previous big one. Failing to take this into account wouldn't be logical.

Once you take that into account, it's difficult to claim that an 8.4 quake couldn't be followed decades later by a 9.0, so I find that an 8.4 is in fact a reasonable precedent for a 9.0. They also knew that the area is a subduction zone like the area off the coast of Chile, which produced a 9.5 magnitude quake in 1960, so they knew a 9.5 quake is possible in a subduction zone, right?

But I do agree with your main point of the topic of your thread, that the construction of the plant for earthquake magnitude alone (tsunamis not considered) was marginally adequate which is supported by the pdf link in my previous post.

Should they have known that they live on an actively subducting island, and taken logical basic safety percautions and used some caution in their choice of building sites?

Yes.

This isn't an accident. Accidents cannot be foreseen. People who've been living on a subducting island whose ancestors put up markers for them about where the waters come to when they roll in don't have an excuse. What they have is overwhelming confidence that they are so perfect that they don't need common sense.

One Diesel Generator.

Now matter how much talk, no matter how much butt covering happens.....this entire problem could have been arrested with a SINGLE diesel generator on site. But they didn't need one. They were sure that in the event of a problem that they could just redirect energy from another nuclear plant to this one. The idea that the neighbouring plants might ALSO be damaged at the same time seems to have eluded their perfect belief in their perfect plan.

Japan, Fukishima, is a perfect example of what happens when workers are not allowed to question the stupid decisions of their bosses.

How much damage did the earthquake do?

Throughout the months of lies and misinformation, one story has stuck: “The earthquake knocked out the plant’s electric power, halting cooling to its six reactors.  The tsunami – a unique, one-off event – then washed out theplant’s back-up generators, shutting down all cooling and starting the chain of events that would cause the world’s first triple meltdown.

All well known and documented.

But what if recirculation pipes and cooling pipes burst, snapped, leaked, and broke completely after the earthquake — before the tidal wave reached the facilities and before the electricity went out? This would surprise few people familiar with the nearly 40-year-old reactor one, the grandfather of the nuclear reactors still operating in Japan.

Granted the tsunami knocking out the emergency generators (placed at grade) would certainly be contributive to the meltdowns, cracked cooling lines would certainly not help either.

In 2002, whistleblower allegations that TEPCO had deliberately falsified safety records came to light and the company was forced to shut down all of its reactors and inspect them, including the Fukushima Daiichi Power Plant.  Sugaoka Kei, a General Electric on-site inspector first notified Japan’s nuclear watchdog, Nuclear Industrial Safety Agency (NISA) in June of 2000.  The government of Japan took two years to address the problem, then colluded in covering it up — and gave the name of the whistleblower to TEPCO.

This shows a history of official corruption and criminal negligence regarding safety at Japan's nuclear plants and within it's regulatory agency.

The problems were not only with the piping. Gas tanks at the site also exploded after the earthquake. The outside of the reactor building suffered structural damage. There was no one really qualified to assess the radioactive leakage because, as NISA admits, after the accident all the on-site inspectors fled

With NISA's history of covering up damage at the plant, it's no wonde they fled because they knew that a major incident was very likely, and eventually did happen as we all know now.

The authors have spoken to several workers at the plant. Each recites the same story: Serious damage to piping and at least one of the reactors before the tsunami hit. All have requested anonymity because they are still working at or connected with the stricken plant. 

The workers are more afraid of not being able to continue working than they are of the radiation continually spewing from the plant.

“I personally saw pipes that had come apart and I assume that there were many more that had been broken throughout the plant.  There’s no doubt that the earthquake did a lot of damage inside the plant. There were definitely leaking pipes, but we don’t know which pipes – that has to be investigated. I also saw that part of the wall of the turbine building for reactor one had come away.  That crack might have affected the reactor.”

The walls of the reactor are quite fragile, he notes.

“If the walls are too rigid, they can crack under the slightest pressure from inside so they have to be breakable because if the pressure is kept inside and there is a buildup of pressure, it can damage the equipment inside the walls. So it needs to be allowed to escape.  It’s designed to give during a crisis, if not it could be worse – that might be shocking to others, but to us it’s common sense.”

So it would seem that a certain amount of brittleness is inherent in the construction from the outset in order to provide for the possibility of an overpressure situation. This would work contrary to structurL integrity in an earthquakesituation though, would it not?

The suspicion that the quake caused severe damage to the reactors is strengthened by reports that radiation leaked from the plant minutes later.  Bloomberg has reported that a radiation alarm went off at the plant before the tsunami hit on March 11.  The news agency says that one of the few monitoring posts left working, on the perimeter of the plant “about 1.5 kilometers (1 mile) from the No. 1 reactor went off at 3:29 p.m., minutes before the station was overwhelmed by the tsunami.”

Whether the problems at Fukushima Daiichi would be as bad had the tsunami not struck and did what damage it did will never be known.
Should they have known better?

Hundreds of so-called tsunami stones, some more than six centuries old, dot the coast of Japan, silent testimony to the past destruction that these lethal waves have frequented upon this earthquake-prone nation. But modern Japan, confident that advanced technology and higher seawalls would protect vulnerable areas, came to forget or ignore these ancient warnings, dooming it to repeat bitter experience when the recent tsunami struck.

reply to post by Arbitrageur

I think if you asked 10 geologists if an 8.4 quake occurs in a location, what are the odds a 9.0 could occur at the same location within the next century, 9 out of 10 would say it's possible.

That actually would be a very interesting test, but I believe you may not - at least before the Japan event - have found so many to agree because areas do have characteristics. As I said previously this mag 9 was NOT expected by ANY geologists either Japanese or anywhere else. It was quite out of character for the area and may have changed the perception of earthquake such that the 10 geologists would now say it was possible - all 10 of them!

Once you take that into account, it's difficult to claim that an 8.4 quake couldn't be followed decades later by a 9.0, so I find that an 8.4 is in fact a reasonable precedent for a 9.0. They also knew that the area is a subduction zone like the area off the coast of Chile, which produced a 9.5 magnitude quake in 1960, so they knew a 9.5 quake is possible in a subduction zone, right?

I can show you areas where there have been mag 8 quakes and have never been a mag 9, or perhaps I should say never yet. There are many subduction zones where there has never been a mag 9, bearing in mind that the only mag 9 earthquakes have been Chile as you state, Alaska, Japan, Indonesia and Kamchatka. Indeed if you look at the list of major earthquakes the next in line are Cascadia and then Equador and then we are back to the usual suspects, so basically any other areas have never had a mag 9. Before this year I would have said they were not likely to, but Japan changed all that.

reply to post by jadedANDcynical

So it would seem that a certain amount of brittleness is inherent in the construction from the outset in order to provide for the possibility of an overpressure situation. This would work contrary to structurL integrity in an earthquakesituation though, would it not?

I would say yes, but I need time to comprehend the stupidity of building something that needs to be brittle in an area where elasticity is required!

I was not aware of this requirement and it would certainly seem that makes the construction of any facility such as this questionable in an earthquake zone.

It has just been pointed out to me that my second graph does not scroll. My apologies, I had not noticed.

I've found this reference to a specific value for the design of the plant.

20 Mar (NucNet): The maximum ground acceleration near unit 3 of the Fukushima-Daiichi nuclear plant from the earthquake that struck northern Japan on 11 March 2011 was 507 gal – or 507 centimetres per second squared – which is above the plant’s design reference values of 449 gal, the Japan Atomic Industrial Forum (JAIF) said today.

It was also announced that the University of Tokyo has re-evaluated the maximum height of the tsunami wave and it had a peak height of at least 23 metres when it hit Miyagi and Fukushima prefectures. The plant design reference value was 10 metres.

From an article at World Nuclear.

Does the 449 gal design reference match with ground movement expected for a 7.9 quake?

Not having ever experienced an earthquake (something you and I have in common puterman) I'm trying to wrap my head around a sudden movement of the ground with that amount of acceleration. that just seems like an incredible energy release.

I know big earthquakes release terrajoules of energy, but thinking about ground acceleration and assigning the types of value in this report somehow brought it home for me.

A chilling first hand account of the quake.

A small red emergency light started blinking. "Then some kind of white smoke or steam appeared and everyone started choking," Nishi said. "We all covered our mouths and ran for the door." But the door leading outside was locked, shut down automatically during the temblor to contain any leakage. The workers were stuck. "People were shouting 'Get out, get out!'" Nishi said. "Everyone was screaming." Pandemonium reigned for about 10 minutes with the workers shouting and pleading to be allowed out, but supervisory TEPCO employees appealed for calm, saying that each worker must be tested for radiation exposure.

Nishi recalled angry shouts from among the workers including expletives from a couple of Canadians. "We were shouting that the reactor structure was going to collapse or that a tsunami might come," Nishi recalled.

He was worried over the collapse of the reactor as an event unto itself separate before the tsunami even arrived.

This was probably one of the Canadians he mentions:

“I thought that building was actually coming down. It was moaning and groaning,” Ayotte recalls. “Everything came down in the office. It just looked like a bomb went off in there after the quake. We all got underneath our desks and rode this thing out. I’d never been so terrified in my life.”

Somewhere was a video interview with this guy the original that Zorgon links in this post is dead.

“The road that we take to work everyday had split wide-open and there was a truck sitting right there in the crevice. Then there was a landslide and all the earth slipped away and took tree down. There were big cracks in the road right near the station,” Ayotte recalls.

I'm thinking that we would still be facing at least one meltdown regardless of the tsunami and maybe more than one.