In a report to the International Atomic Energy Agency (IAEA), the Japanese government stated that the Fukushima Daiichi nuclear disaster was caused not by the Tohoku earthquake but by the tsunami it generated, resulting in a loss of power for the station’s cooling systems and, consequently, three core meltdowns. The tsunami countermeasures taken when Fukushima Daiichi was designed in the 1960s were, arguably, marginally acceptable considering the scientific data then available. But, between the 1970s and the 2011 disaster, new scientific knowledge emerged about the likelihood of a large earthquake and resulting tsunami; however, this was ignored by both the plant operator, Tokyo Electric Power Company, and government regulators. The regulatory authorities failed to properly review the tsunami countermeasures in accordance with IAEA guidelines and continued to allow the Fukushima plant to operate without sufficient countermeasures, despite having received clear warnings from at least one member of a government advisory committee. The lack of independence of government regulators appears to have contributed to this inaction. The anzen shinwa (“safety myth”) image portrayed by the Japanese government and electric power companies tended to stifle honest and open discussion of the risks. Japan’s seismological agencies are locked into outdated and unsuccessful paradigms that lead them to focus on the hazard of a supposedly imminent earthquake in the Tokai district, located between Tokyo and Nagoya, while downplaying earthquake hazards elsewhere in Japan. Consequently, regulators and the plant operator missed many opportunities to avert the calamity at the Fukushima Daiichi Nuclear Power Station.