A Japanese scientist in 2009 pointed to a possibility of giant tsunami hitting the Pacific coast of the nation’s Tohoku northeastern region, but the warning was not looked to by Tokyo Electric Power Co. <9501>, which is now struggling to combat radiation leaks from its tsunami-hit nuclear power plant in the same region, it was learned Sunday.
Yukinobu Okamura, chief of the Active Fault and Earthquake Research Center of the National Institute of Advanced Industrial Science and Technology, or AIST, issued the warning at a meeting in June 2009 of a Ministry of Economy, Trade and Industry panel on earthquake safety of nuclear power plants.
Okamura carried out a study on the 869 Jogan earthquake that jolted the Tohoku region and unleashed massive tsunami, and found that layers of sand driven by the tsunami are observed in inland locations including areas around Tokyo Electric Power’s Fukushima No. 1 and No. 2 nuclear plants in Fukushima Prefecture, which is part of Tohoku. He also argued that huge tsunami has hit the region once every 450-800 years. At the 2009 meeting of the panel, Okamura said that tsunami waves far bigger than those anticipated by the power supplier could hit the Tohoku region, citing the results of his study on the Jogan quake, which is seen to have had an estimated magnitude of up to 8.4 on the current open-ended Richter scale.
Okamura urged the panel to review nuclear plants’ quake resistance in terms of tsunami. But Tokyo Electric Power argued that it is unnecessary to take the Jogan quake into account in the quake-proof design of nuclear power plants, noting that the quake occurred more than 1,100 years ago.