April 14, 2011

Japan’s Earthquake Prediction System Flawed

A leading scientist on Wednesday said that Japan's northeastern coast has suffered many powerful earthquakes and large tsunamis in the past and nuclear power plants should have been built to withstand these natural disasters, reports AFP.

The scientist also noted that the crippled plant in Fukushima may have survived the disaster had the government not put faith in a flawed earthquake prediction system.

Geophysics professor Robert Geller said the Japanese authorities rely on annual "hazard maps" to highlight parts of the country deemed at higher risk from major temblors, but there is no reliable scientific basis for that technique.

Japan's seismologists were so reliant on their outdated beliefs about seismic hazards that they became blinded to the risk of the March 11 quake, Geller commented in the science journal Nature on Wednesday.

Geller, an American who is professor of seismology at the University of Tokyo, said the Japanese scientists had become entrenched by the risk of a big earthquake on Japan's southern Pacific coast. This had altered their view of the risks for the country"Ëœs northeast, where the 9.0-magnitude quake and tsunami struck, destroying many lives.

Geller said Japanese seismologists believed that imminent risks of a huge earthquake were concentrated in a plate boundary off the southern coasts of Honshu and Shikoku.

Hazard maps of the Tokai, Tonankai and Nankai "earthquake zones" are promoted heavily in public awareness ads and have gained the status of the holy wit, he said. However, these maps are based on two assumptions -- the "characteristic earthquake" and "seismic gap" theories -- which date from the 1960s and 70s and have not been supported with evidence.

"This misleads the public into believing that the clock is ticking down inexorably on a magnitude-eight earthquake that is certain to strike the Tokai district in the near future," he said in his commentary piece.

Since 1975, no large earthquakes have occurred in any of the three zones considered as high risk by Japanese government scientists. In contrast, all quakes that have caused 10+ fatalities in Japan since 1979 have occurred in places the government categorized as low probability, said Geller.

Geller argued that if scientists studied historical records showing the northeastern coast being struck more often over the past centuries, they may have had some general forewarning of the March 11 disaster.

While timing and exact location would not have been known, its potential force could have been factored into the design of the Fukushima Daiichi nuclear power plant, he added.

Established thinking from the public and scientific community had been modeled by a 1978 law, the Large-Scale Earthquake Countermeasures Act (LECA), which requires the Japan Meteorological Agency (JMA) to operate an alert system based on the assumption that early warning can be given of a Tokai temblor.

"It is time to tell the public frankly that earthquakes cannot be predicted, to scrap the Tokai prediction system and to repeal the LECA," said Geller. "All of Japan is at risk from earthquakes, and the present state of seismological science does not allow us to reliably differentiate the risk level in particular geographic areas."

Geller, commenting on the risk of tsunamis, singled out two that have devastated the region in the past 1200 years: the 125-foot Sanriku tsunami of 1896 that killed 22,000 and the Jogan tsunami of 869 that was similar in size to the March 11, 2011 tsunami.

"There were very many documented large tsunamis in that area but the point is ... even one would have been enough to warrant precaution in designing nuclear power plants," Geller told Reuters in a telephone interview.

The Fukushima nuclear plant, which has been leaking radioactive substances for more than a month now, was designed to handle a wave up to 20 feet high -- way below the 45-foot tsunami of March 11, and much below these other giants of the past.

"It's known to have happened before and it's well documented and so when they built a nuclear power plant they should have provided for a tsunami of the same size," said Geller.

He said all nuclear plants in Japan should be reviewed to ensure they can handle another tsunami. "They definitely should, they are almost all on the oceanfront. You need a lot of water to cool them."

Residents and business owners who were forced to leave their homes amid fears of radiation on Wednesday demanded immediate answers from the company at the heart of the nuclear crisis. About 20 of those who had been evacuated from the area around the disabled plant protested outside the Tokyo Electric Power Company headquarters, calling for quick response and a decision on possible compensation.

TEPCO president, Masataka Shimizu, apologized during a rare public appearance and said he planned to compensate the tens of thousands of people whose lives have been disrupted by the nuclear disaster.

"They might have been forced into using a more expensive design than they could have afforded, but a lot of people might have appreciated that, especially the people in Fukushima who have been evacuated," Geller told The Guardian. "If the cost was too much to design for, they would have had to go without the nuclear reactor."

He said the government's faith in the flawed system means some areas are left unprepared for a possible emergency. "It is a waste of time and money, but worse than that, if the public think you can predict earthquakes, it tends to lull them into a false sense of security. Because of the limitations of our knowledge and data, we really cannot do more than say the whole place is dangerous," he said.

"These decisions should have been made in a more transparent way. The public should have been clearly informed what were the risks, what design decisions had been made and so on. But the government took the stance that these things were completely safe, that there was no risk whatsoever," Geller noted.


Image Caption: Map of the Senadai Earthquake 2011 Credit: Wikipedia


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