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This is the last in a series of investigative reports from the Chunichi Shimbun about how figures for the probability of a Nankai Trough earthquake were manipulated for a government expert panel report released in February 2018.

When a government panel of earthquake prediction experts revised the probability of the Nankai Trough earthquake scenario from “about 70 percent” to “between 70 and 80 percent” in February 2018, some pointed out that the figure was inflated. The minutes of previous meetings in 2012 and 2013, obtained by the Chunichi Shimbun, revealed the figure had been slammed as “unscientific” at the time.

The seismologists were of the opinion that the probability was not being presented fairly and called for the release of not only the highest figure but a low one as well.

But their argument was swiftly shot down by scholars in the field of disaster prevention, who, the minutes of the preliminary meetings showed, made no secret of their desire to prioritize securing themselves budgets over respecting science.

This was reflected in the way the two figures were presented to the public.

During joint sessions the committee held in December 2012 and February 2013, seismologists and disaster prevention experts clashed over whether to mention the low figure for the Nankai scenario in the “main text,” or summary, of the government report.

In the draft version, there was no mention of the fact that the time-predictable model — the measurement of land movements from previous quakes taken at Murotsu Port, northwest of Cape Muroto in Kochi Prefecture — was applicable only to the Nankai scenario, and that applying the model used for all other earthquakes would slash the probability to about 20 percent.

Although the lower figure was briefly mentioned later in the report, it was buried at the bottom, a location that could invite criticism that it was the committee’s intent to hide it.

It was risky for the seismologists as well. To simply mention a probability derived from the time-predictable model, which lacks widespread backing, would damage the credibility of the seismologists as well.

The options

Yasuhiro Yoshida, an education ministry official, proposed four options; 1) don’t disclose any probability figures; 2) disclose only the 20 percent figure because it is the most scientifically accurate one available at the moment; 3) disclose both the 20 percent figure and the time-predictable figure; 4) disclose both figures but mark one with an asterisk to denote it’s more official than the other.

But all four proposals were shot down by the disaster prevention experts during a joint of the committee at the end of 2012.

A few months later, in February 2013, another committee meeting was held, during which the bureaucrats came up with four new options on how to present the summary: 1) present both the high and low figures; 2) propose the high figure as main probability and add the low figure as a reference; 3) omit the low figure (which was the initial idea); 4) downgrade the high figure as a reference and omit the low figure.

The bureaucrats pointed out that option 3 was the one the seismologists wanted to avoid the most because it “poses a huge problem from a scientific viewpoint.”

But that was the option they ended up with.

The minutes, which didn’t refer to who exactly made the remarks, showed that the members were initially leaning toward inserting both figures, high and low.

The Headquarters for Earthquake Research Promotion, headed by the education minister, is allocated about ¥8 billion to calculate the 30-year probability figures for earthquakes nationwide and creating maps that reflect them. | KYODO
The Headquarters for Earthquake Research Promotion, headed by the education minister, is allocated about ¥8 billion to calculate the 30-year probability figures for earthquakes nationwide and creating maps that reflect them. | KYODO

“It won’t be a big problem, presenting both figures. (Depending on the calculation methods) the figures could be very high and very low. We can ask (governments) to take (disaster prevention) measures based on the higher figure,’’ one member of the committee said.

“If we stick to the (high probability) time-predictable model, we may lose focus on what we should be doing and which direction to head toward. (The policies) may shift away from the direction of future research and science. (The low figure) definitely needs to be disclosed,’’ another member said.

“Reporters would no doubt question this. We can’t hide” the low figure, another said.

Those supporting option 3 were definitely in a minority. But one member pushed strongly for it, arguing it was important to secure a budget first, changing the course of the discussion.

Another member then supported the idea.

“What happens if, in the near future, new research comes along that requires us to recalculate the figures. That would cause confusion among the public. I’m not sure if we want to give the impression that the figure will suddenly be reduced to 10 to 20 percent. I want scientists to do more research,’’ the member said.

In any meeting, those who are vocal may sway the course of discussion even if they are small in number. To me, from reading the minutes, that seemed to be what happened.

Buying time

“People would be surprised if we suddenly released this (low figure) as an official report,’’ said one member.

“It may be better to brief reporters by next time and have them report on it first as the latest science in seismology, laying the groundwork. To buy time until then, the answer may be option 3,” another said.

“If we opt for option 3, I fear that people won’t look at the other necessary information. I’m torn in half,’’ said another.

One member was reluctant to put the 20 percent figure anywhere in the report.

“I’m okay with option 3, but if we put (the low figure) in the report, it’ll give the impression that the probability will decline this much. You should all be aware that that would become the headline,” the member said.

That remark was the final nail in the coffin. A member who appears to have been the moderator put an end to the discussion.

“With today’s hot discussion, please note in the minutes that we have judged at this point that option 3 is the most suitable among the four proposals,” the member said.

This is how the lower figure proposed by seismologists and the discussions on the proposal disappeared completely from the summary.

There are two reasons why I thought it was important to disclose the minutes.

One is because the official projection — that there is a 70 to 80 percent probability of a Nankai Trough earthquake occurring in the next 30 years — was mentioned in the report as if it was scientifically proven, when seismologists in fact argued they were “scientifically problematic.”

I am not trying to play down the dangers of the scenario, nor am I saying that governments shouldn’t prepare for it. It’s true a Nankai quake could cause tremendous damage to the infrastructure of central Japan. But if authorities are using selective methods just for the sake of pumping up countermeasures, that’s a problem.

Needless to say, the basic data used to form the nation’s policies should be based on science. The fact that authorities appear to have manipulated data to secure a budget and other nonscientific reasons is tantamount to treason against the public and science.

Hiding the documents

Another reason is the government’s reluctance to disclose public documents or the minutes of the committee’s discussions.

The education ministry did not disclose all of the minutes at first. An official in charge initially said certain minutes cannot be disclosed because they don’t exist. These were the minutes that included such shocking comments as, “We should give priority (to disaster prevention measures) in allocating taxpayers’ money,” and “First and foremost, we need to secure the budget,” that led to the 80 percent figure appearing prominently in the summary.

I learned of the existence of the minutes after finding comments in a pile of other minutes that hinted to such remarks by chance.

“There was a very sensitive discussion. Was it deleted from the minutes because it will be considered as applying pressure on the Earthquake Research Committee?” one member asked, according to the minutes.

“They will not be disclosed if it is deemed to have a significant impact on society. But if there is a request for disclosure, we will release them,” replied a bureaucrat.

Knowing from the minutes that the ministry had agreed at a committee meeting to disclose them, I asked the education ministry once again to release all of the minutes.

Due to deliberations in the ministry, the minutes were disclosed after more than a month longer than usual. They were partially blacked out, and the reason for that was astonishing.

“If this kind of information becomes public, the government and municipalities will be flooded with phone calls from the public and media outlets, making it hard for them to conduct their administrative work properly,” the ministry responded in writing.

If this kind of reasoning is tolerated, it surely means governments and municipalities don’t have to disclose any information if they don’t want to.

In recent years, the government has covered up facts deemed to reflect negatively on it. The Defense Ministry hid a daily log written by Ground Self-Defense Force personnel regarding the security situation on the ground in Iraq, while the Finance Ministry doctored documents involving nationalist school operator Moritomo Gakuen’s heavily discounted purchase of state land for a new school. More recently, government officials shredded documents containing the guest list for a state-funded cherry blossom-viewing party hosted by Prime Minister Shinzo Abe on the same day it was requested, triggering accusations that they did it on purpose.

If ministries try to hide public documents, the public will lose trust in them. The same goes for the Headquarters for Earthquake Research Promotion.

Japan has long relied heavily on earthquake predictions, pouring money and other resources for disaster prevention into the Tokai region. Following the 1995 Great Hanshin Earthquake, the Headquarters for Earthquake Research Promotion was founded on the premise that policies that had been formed on the basis of earthquake prediction had been a failure.

No one knows when and where an earthquake may strike. If authorities continue to focus on the Nankai Trough scenario and amplify its dangers, the lessons learned from the 1995 Hanshin earthquake will cease to exist.

Touting ‘low risk’ regions

In fact, it is already causing negative effects. Before the major earthquakes in Kumamoto Prefecture in 2016 and Hokkaido in 2018, municipalities in the prefectures had been wooing businesses, saying their regional quake risks were lower than in places where the Nankai Trough quake was projected to strike.

The two prefectures suspended their campaigns after the quakes, but there are still many municipalities trying to sell themselves as places with a low risk of disaster.

About ¥8 billion in state funds are allocated every year to the Headquarters for Earthquake Research Promotion. Its two main functions are calculating the 30-year probability figures for earthquakes nationwide and creating maps that reflect them.

But in recent years, earthquakes have been striking places the map showed to have low probability, causing damage.

Every time I go to disaster areas for reporting, survivors say it was unexpected and that they were unprepared, thinking the Nankai Trough was where the next big one would hit. If the government and seismologists don’t disclose accurate information, this kind of “misunderstanding” will carry on, causing more damage.

It is everyone’s dream to predict where the next earthquake will hit and concentrate limited funds and resources there to minimize the risk. But at present, it is impossible to predict that with accuracy.

The key may be not to predict the future but to introduce where past earthquakes have struck, thereby giving the impression that it could happen anywhere. And the first step is to revise the methods used to calculate the 30-year probability of the Nankai Trough earthquake as soon as possible.

Keiichi Ozawa received the science journalist award, presented by the Japanese Association of Science & Technology Journalists in June, for this series published between October and December 2019.

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