The estimated maximum tsunami, or design tsunami
height, at the Fukushima Dai-ichi Nuclear Power Station
was 6.1 m, based on the M 7.5 earthquake which occurred
in 1938. The long-term forecast of Earthquake Research
Committee indicated that a “tsunami earthquake” may
occur anywhere along the Japan Trench. The tsunami
height at the Fukushima Dai-ichi Station from the Jogan
earthquake model was estimated as 8.9 m, and that from a
“tsunami earthquake” off Fukushima was calculated as
15.7 m by Tokyo Electronic Power Company, but no preventive
actions were taken. For critical facilities such as a
nuclear power plant, the seismological progress should be
closely monitored and reflected in safety preparedness.