Higashidori fault not active, according to utility

January 17, 2014

Operator: faults in Higashidori plant not active

http://www3.nhk.or.jp/nhkworld/english/news/20140117_46.html 

The operator of the Higashidori nuclear power plant in northern Japan says 2 faults under the facility are not active.

Tohoku Electric Power Company released the results of a fresh survey it conducted of the plant in Aomori prefecture on Friday.

The extra survey was held through December, after a Nuclear Regulation Authority panel said that the faults appear to be active.

The utility says analysis of samples taken from 120,000 to 130,000-year-old strata around the faults found they were solid rock, showing they have not moved in at least the past 130,000 years.

It also says no traces of destruction of the strata -- often caused by active faults -- have been observed.

NRA experts cited distortion in the strata as a grounds for their stance that the faults are likely to be active.

The company says the distortion in some sections has not been confirmed and in others it may have been created after the soil absorbed water.

Tohoku Electric concludes that its survey found no traces of the faults having moved in the past and suggested they are unlikely to move in the future.

The NRA experts plan to compile a final report based on 4 rounds of field surveys and the results of the utility's additional survey.

If the faults were found to be active, Tohoku Electric would be required to review its anti-quake measures, making it likely that the Higashidori plant would be kept offline.

Jan. 17, 2014 - Updated 12:24 UTC