Regulators: Faults beneath Higashidori nuclear plant likely active

December 15, 2012

THE ASAHI SHIMBUN

Fault lines beneath the Higashidori nuclear power plant in Aomori Prefecture may be active, Nuclear Regulation Authority experts said on Dec. 14.

The announcement was made the same day the industry watchdog completed its two-day on-site survey of the plant, which is operated by Tohoku Electric Power Co. Another nuclear plant that carries the same name is under construction in Higashidori by Tokyo Electric Power Co.

Experts on the NRA's five-member panel told a post-survey news conference that they believed that shifts in geological formations across the fault lines being studied represent activity during the past 100,000 years.

The movements may have been induced by slippage along an active fault that lies elsewhere, but it cannot be ruled out that the surveyed faults are themselves seismically active, according to the panel members.

"There is repeated activity," said Hiroshi Sato, a professor of structural geology at the University of Tokyo. "I believe the faults are active."

NRA Deputy Chairman Kunihiko Shimazaki, who heads the panel, said the opinions of the panel members are "looking toward the same direction."

They are scheduled to meet on Dec. 20 in Tokyo to officially conclude whether the fault lines are active. An assessment that they are active would make it difficult to restart the nuclear reactor at the plant in the near future.

(This article was written by Ryuta Koike and Yu Kotsubo.)

THE ASAHI SHIMBUN
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Members of a Nuclear Regulation Authority expert panel study geological formations along a fault line on the premises of the Higashidori nuclear power plant in Aomori Prefecture on Dec. 14. (Pool)

Members of a Nuclear Regulation Authority expert panel study geological formations along a fault line on the premises of the Higashidori nuclear power plant in Aomori Prefecture on Dec. 14. (Pool)

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  • Members of a Nuclear Regulation Authority expert panel study geological formations along a fault line on the premises of the Higashidori nuclear power plant in Aomori Prefecture on Dec. 14. (Pool)
  • The Higashidori nuclear power plant in Aomori Prefecture (Asahi Shimbun file photo)

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