Japanese media, including at least the Daily Yomiuri (www.tinyurl.com/3pqezgd) and NHK, have reported that an analysis for TEPCO had predicted the possibility of a 10-metre tsunami at Fukushima Daiichi and Daini in 2008, but TEPCO did not act to improve defences.
Now, TEPCO has defended its position. "Our position is that the trial analysis was conducted voluntarily by assuming severe conditions without reasonable wave source models," a spokesman said.
A 2008 trial analysis using the 1896 Meiji-Sanriku tsunami was based on a hypothetical model that did not include a wave source model for the Fukushima prefecture's Japan trench line, since tsunami had not happened there before. In another analysis, Dr Satake of the National Institute of Advanced Industrial Science & Technology concluded that additional surveys were required to apply the 896 Jogan tsunami analysis to the Fukushima plants, TEPCO said. The spokesman added that TEPCO requested the revision of wave source models and tsunami evaluation technology from the Japan Society of Civil Engineers.
The spokesman also denied media reports that Japanese regulator NISA had instructed it to prepare for larger tsunami.
TEPCO has published a timeline of major tsunami preparations at the Fukushima site, which is copied below.