Abstract
In the event of a critical situation caused by volcanic disaster, a decision maker engaged in crisis management needs to select decision guides which are different from an ordinary decision mode. This study claims that relevant issues for volcanic crisis management change as disaster stages proceed and examines decision problems in each stage on the basis of the case of Mt. Usu. It also compares ordinary and emergent decision modes as the two decision modes for crisis management. Furthermore, it discusses the meta-principle to change decision modes according to the disaster stage and presents a normative framework to legitimize the change in decision modes through deliberative systems.
