2022 年 25 巻 p. 19-35
The need for risk management in activities in nature is widely recognized, but it is suspicious that formal risk management methods are easily adopted, in which risks are analyzed with damage and probability matrix. In personal activities, the probability information of occurrence of damage is not sufficient, and the damage and probability are not substitutable. Even in the similar situation, the risk varies among persons or among situations, and risks rapidly change in a short period of time. In personal activities, it is necessary to treat such risks that are difficult to handle within the framework of formal risk management methods. Based on this recognition of issues, after examining decision-making theories in extreme environment, and based on researches on practical knowledge of risk management in the natural environment, we proposed a framework with the core concept such as time phase of risk management (on site or off site), risk increasing factors, controllability, and suddenness, which contributes to individual risk management in the field with high uncertainty. Its significance and limitations were also discussed.