Separate investigations by an official Japanese commission, the I.A.E.A. and other entities put much of the blame on poor regulatory oversight and a lack of preparedness despite Japan's history of earthquakes and tsunamis.

来自日本官方委员会、IAEA和其他机构的单独调查在很大程度上将责任归咎于监管不力和缺乏准备，尽管日本有地震和海啸的历史。