Fate and denial: The Fukushima reactor 3, and the L’Aquila earthquake 7

OPINION by John C. Mutter, Ph.D.
Professor of Earth & Environmental Sciences and Professor of International & Public Affairs, Columbia University
; Director of Graduate Studies Ph.D. Program in Sustainable Development
; Director of the Earth Institute Post-Doctoral program


 
The recent acquittal of the TEPCO executives in the Fukushima power plant tragedy hearkens back to the trial of the Italian seismologists who were charged with negligence after the L’Aquila, Italy, earthquakes. Both events raise the question: How much do you prepare for the most dreadful disasters, which result from truly large or rare paroxysms of the Earth?
 
Citation: Mutter, J.C., (2019), Fate and denial: The Fukushima reactor 3, and the L’Aquila earthquake 7, http://doi.org/10.32858/temblor.054
 

A sightseeing boat hurled onto a two-story building at Otsuchi, Iwate prefecture, by the 2011 Tohoku tsunami. This means that the tsunami barrier, visible at left, was overtopped by at least 10 m (33 ft).
A sightseeing boat hurled onto a two-story building at Otsuchi, Iwate prefecture, by the 2011 Tohoku tsunami. This means that the tsunami barrier, visible at left, was overtopped by at least 10 m (33 ft).

 

Three TEPCO (Tokyo Electric Power Company) senior management executives had been charged with negligence for their role in the Fukushima power plant tragedy that resulted from overtopping of protective walls around the plant. All have been acquitted of all charges. Reaction in Japan varied from outrage to a grudging, “of course; that’s what always happens.”

According to Japanese NHK, Kyodo News, Presiding Judge Kenichi Nagafuchi, in handing down the decision, said: “It would be impossible to operate a nuclear plant if operators are obliged to predict every possibility about a tsunami and take necessary measures.” That’s fair; no one can know everything about tsunamis. But we do know some things; in fact, we know quite a lot.

 
What we know about tsunamis

Tsunamis are generated by earthquakes that cause movement of the seafloor of the ocean. Because of that, a tsunami wave is nothing at all like a wind-driven ocean wave; tsunami waves advance relentlessly across oceans and build in height as they approaching shore. Tsunamigenic earthquakes occur mostly where two tectonic plates are steadily advancing toward one another. That means they do not occur everywhere in the world, and we know, from long experience, just where they are likely to occur. The east coast of Japan is one such place. Tsunamis are no stranger to Japan; the word itself is Japanese for “harbor wave,” though that is hardly an adequate description of these awful tyrants of nature. Parts of Japan even have seawalls to protect against tsunamis, including at Fukushima; they just weren’t high enough.

 

The 11 March 2011 tsunami overtops the tsunami barrier along the Tohoku coastline at Miyako, 120 km north of Sendai, Japan. Here you can see that tsunamis are not just water. They entrain massive amounts of heavy floating debris, including boats, cars, and buildings, which increase their lethal power.
The 11 March 2011 tsunami overtops the tsunami barrier along the Tohoku coastline at Miyako, 120 km north of Sendai, Japan. Here you can see that tsunamis are not just water. They entrain massive amounts of heavy floating debris, including boats, cars, and buildings, which increase their lethal power.

 

Similarities with the L’Aquila trial

It’s hard to think of this tragedy and not be reminded of the L’Aquila seven — the members of the Italian Major Risks Committee who were charged with negligence following the L’Aquila earthquake of April 6, 2009. Six were acquitted, and one received a suspended sentence. They were not charged with failing to make an accurate prediction of an earthquake, despite what thousands of seismologists around the world said, well before an English translation of the Italian language indictment was available. (Aren’t scientists supposed to work with data?) As the prosecuting attorney, Fabio Picuti allegedly stated, “Even a six-year-old knows you can’t predict earthquakes.”

 

Former President Obama and former Prime Minister Berlusconi tour the L’Aquila damage in 2009.
Former President Obama and former Prime Minister Berlusconi tour the L’Aquila damage in 2009.

 

You don’t have to be a six-year-old protégée to know this: If we could predict earthquakes, we would, and because we can’t, we don’t. Everyone knows that, including the seven members of the Major Risks Committee. They were charged with the manslaughter of 29 victims who, it was claimed, would not have died, had they not heeded the flippant, irresponsible statements from one member of the committee (its lone politician, not from the scientists), and returned to their homes in the evening to sleep. Everyone knows that earthquakes don’t kill people — buildings kill people — so many residents of L’Aquila had been sleeping outdoors when a series of tremors had raised concerns that something more dreadful was at hand. And as it turned out, they were right.

 
Working with what we know

We can’t know everything about earthquakes, and we can’t know everything about tsunamis. But we can act responsibly with what we do know. Seawalls were constructed around Japan to a height that seemed reasonable. In the region offshore Japan where earthquakes have the potential to be tsunamigenic, the largest earthquakes recorded for decades and decades were not much more than 7.5 in magnitude.

No seismologist is foolish enough to think that a larger earthquake was impossible. But the persistent recording of earthquakes up to, but not exceeding M7.5, led seismologists to think that conditions on the subducting plate in contact with the plate overriding it were such that when stress built to a level sufficient to create a Magnitude 7.5 earthquake, the crust would always rupture. The plate boundary could not, they thought, sustain higher stresses that would, in failure, create a larger earthquake. So, the walls were built to the tsunami height expected for a Magnitude 7.5 earthquake. That is neither flippant nor irresponsible. It seemed to make perfectly good sense.

 

Rubble from the Fukushima Daiichi Nuclear Power Plant caused by the 2011 earthquake and tsunami. Photo by Gill Tudor for IAEA
Rubble from the Fukushima Daiichi Nuclear Power Plant caused by the 2011 earthquake and tsunami. Photo by Gill Tudor for IAEA

 

Then the inconceivable happened — a Magnitude 9.0 earthquake where there had never been one before. Well, maybe not never. There is evidence that more than a thousand years ago, an earthquake of similarly huge magnitude had, in fact, occurred. But those planning for the height of the wall allegedly didn’t know that. Even had they known that once, a thousand years ago, there had been a Magnitude 9.0 earthquake with a huge tsunami wave, would they have built the walls twice as high? That’s at least what it would take to be sure to be safe.

 
How do you prepare?

This presents one of the most vexing questions for people working in disaster risk assessment. How much do you prepare for the most dreadful disasters, which result from truly large paroxysms of the Earth? Thankfully, these happen so rarely that they can almost be dismissed as statistical aberrations. In discussing these events, it’s common to cite Nassim Taleb’s “Black Swan” — something that is unpredictable, having a massive impact, for which after the fact, an explanation is concocted that makes it appear less random and more predictable than it was.

Very large earthquakes are not exactly random events, but they occur so infrequently that they might as well be. So now what? First, be honest. The science is not yet available to come anywhere close to predicting monster earthquakes, or any-sized earthquake for that matter. If you live anywhere near a subduction zone, it’s kismet whether you will experience the monster. In L’Aquila, it’s kismet whether a modest-sized earthquake will cause your roof to fall in and kill you in bed while you sleep. That’s how most people there died.

Of course, you could fortify your roof in L’Aquila, and you could build enormous walls in Japan. Or maybe enormous walls around critical infrastructure, like nuclear power plants; that makes some sense. But at what cost? In all of these cases, you have to have the means and motivation to weigh the costs against the risks. It’s the same wobbly rationale that causes so few people to have earthquake insurance. And the more the events you are preparing for seem random, the more people leave the consequences to fate. Denial is a coping mechanism.

But whether denial should be a coping mechanism around a nuclear power plant is another question entirely. The judge in the case clearly said that they prepared adequately, given what was known at the time. The question now is: What will the next seawall look like?

 

References

Dooley, B., Yamamitsu, E. and Inoue, M., “Fukushima nuclear disaster trial ends with acquittals of 3 executives.” New York Times, Sept. 19, 2019.

Oskin, B., “Japan earthquake and tsunami of 2011: Facts and information.” Live Science. Sept. 13, 2017.

Mutter, J.C., “An economic argument for reframing the geoscientist’s role in disaster mitigation.” EARTH Magazine. May 2017.

Sawai, Y., et al., “Shorter intervals between great earthquakes near Sendai: Scour ponds and a sand layer attributable to A.D. 1454 overwash.” Geophysical Research Letters. June 1, 2015.
https://doi.org/10.1002/2015GL064167.

Namegaya, Y., and Satake, K., “Reexamination of the A.D. 869 Jogan earthquake size from tsunami deposit distribution, simulated flow depth, and velocity.” Geophysical Research Letters. Jan. 16, 2014. https://doi.org/10.1002/2013GL058678.

Oskin, B., “Two years later: Lessons from Japan’s Tohoku earthquake.” Live Science. March 10, 2013.

Gammon, C., “Ancient earthquake foreshadowed 2011 Japan disaster.” Live Science., Dec. 13, 2012.

Sawai, Y., et al., “Challenges of anticipating the 2011 Tohoku earthquake and tsunami using coastal geology.” Geophysical Research Letters. Nov. 9, 2012. https://doi.org/10.1029/2012GL053692.

Mutter, J.C., “Voices: From Haiti to Japan: A tale of two disaster recoveries.” EARTH Magazine. March 2012.

Mutter, J.C., “Voices: The confounding economics of natural disasters.” EARTH Magazine. July 2011.

Mutter, J.C., “Voices: Italian seismologists: What should they have said?” EARTH Magazine. July 1, 2010.

Mutter, J.C., “Voices: Should science dictate whether to rebuild after a natural disaster?” EARTH Magazine. May 2010.

  • Teresa Ramirez

    If geologic evidence (dating back hundreds to thousand of years) of tsunamis and earthquakes are considered in any hazard planning, we would have different results and prevent tragedies.

  • Van Snyder

    The Fukushima reactors were not damaged by the earthquake. They shut down automatically, as they were supposed to do. They thereby had no power for coolant circulation, except their auxiliary diesel generators. Eight years before the earthquake, TEPCO had been told by the Japanese Nuclear Regulatory Commission to shut down the Fukushima reactors. They begged for permission to keep them open. The Japanese Nuclear Regulatory Commission allowed them to remain open, provided they sought advice from the US Nuclear Regulatory Commission. The US Nuclear Regulatory Commission told them to move the auxiliary generators out of the reactors’ basements to higher ground, and to bury the fuel tanks on high ground instead of leaving them on stilts on the beach, albeit behind the seawall. When the tsunami arrived, it filled the generators in the basements with mud and washed away the auxiliary fuel tanks, because TEPCO had ignored the advice that was the condition to keep the reactors open. The reactors thereby had no auxiliary power for coolant circulation, which resulted in the damage we all know about. The height of the seawall was not the real issue. The judge was mistaken to use that as his desideratum. The executives should have been convicted.

  • Concerned engineer

    The paper does not address the lack of due diligence in system safety assessment, nothing to due with earthquake magnitude.

    Regardless of the height of the tsunami barrier based on the probability of the magnitude of the earthquake, there was a fundamental flaw in the safety analysis. Probability is allowable for functional failures, eg loss of cooling, loss of regulation, etc. This defines the architecture of the system to avoid catastrophic events, and may require mitigation or backup systems, such as those that were unfortunately located in the basement of the building. But the safety analysis should also conduct a particular risk analysis (PRA) for foreseeable events that have common cause effects, eg, fire, flooding, earthquake, lightning, high winds, human error, etc. PRAs have a probability of 1. You must assume they will occur regardless of probability, and develop countermeasures.

    To prevent this disaster, locate the backup systems or separate them so that flooding cannot affect them all (common cause). The cause of the flooding is moot, be it unintentional or malicious human error, water leak, typhoon, tsunami, etc. Eliminate or mitigate the common cause!

    See aerospace approaches: Federal Aviation Regulation 25.1309 and associated advisory circular AC25-1309. Also SAE standards ARP4761 & ARP4754.

    In this case, those responsible for the design and system safety analysis and the regulators responsible for safety compliance might rethink their due diligence.

    Thus the issue is NOT the probability of the M9.0 earthquake, or the height of the tsunami, but asking what happens if the backup cooling system fails. The answer is that the event is catastrophic. One of the multiple PRAs is flooding, which can occur from a variety of natural and external events. Therefore flooding cannot occur, or the backup system must be designed for flooding.