According to the researcher, Yukinobu Okamura, and the records of a government council where he made the warning, TEPCO asserted that there was flexibility in the quake resistance design of its plants and expressed reluctance to raise the assumption of possible quake damage citing a lack of sufficient information.
”There should be ample flexibility in the safety of a nuclear power plant,” said Okamura, head of the Active Fault and Earthquake Research Center at the National Institute of Advanced Industrial Science and Technology. ”It is odd to have an attitude of not taking into consideration indeterminate aspects.”
Okamura had warned in 2009 of massive tsunami based on his study since around 2004 of the traces of a major tsunami believed to have swept away about a thousand people in the year 869 after a magnitude 8.3 quake off northeastern Japan.
He had found in his research that tsunami from the ancient quake had hit a wide range of the coastal regions of northeastern Japan, at least as far north as Ishinomaki in Miyagi Prefecture and as far south as the town of Namie in Fukushima Prefecture — close to the Fukushima Daiichi plant — penetrating as much as 3 to 4 kilometers inland.