Abstract
If the Great East Japan Earthquake is analyzed from a viewpoint of a risk theory, four fundamental risks exist there. There is “tsunami risk” relating to a tsunami hazard, and “nuclear power plant risk” relating to a nuclear power plant disaster. These two risks are divided into “before-disaster risk” of being involved in generating of disasters and the “after-disaster risk” concerning revival of a stricken area. The aim of this paper is in analyzing the structure common to generating of these four risks, clarifying the relation of risk management and knowledge, risk and ignorance. In both of the tsunami disaster and the nuclear power generation disaster, the paradoxical situation where a new risk occurs by the risk management has arisen. This paradox comes from “spiral motion of the ignorance” that ignorance converts into known by work of knowledge, and new ignorance is born.
