Numerical model for estimating period of disaster response

Toshihiro TERUNUMA, Hideaki MIZUNO and Haruo NISHIMOTO

If sediment disaster risk has increased because of such processes as natural damming of a river, the authority responsible for disaster prevention measures must judge, as promptly and accurately as possible within the framework of limited human resources, whether it is necessary to issue an evacuation order or advisory or not. That requires providing training so that the organization has efficient, uniformly trained personnel. Generally speaking, efficiency can be improved by increasing the ratio of finished work and decreasing the ratio of rework necessitated by calculation or other errors included in the obtained results. If the degree of effectiveness of such training is to be evaluated quantitatively, it is necessary to analyze the ratio of finished work and the ratio of rework in view of the time required for obtaining accurate results. In this study, a mathematical model consisting of a one]dimensional advection]diffusion equation that approximates Kolmogorov's forward equation was proposed as a means of estimating the time required for disaster response activities. The proposed mathematical model was applied to the training to be provided for emergency surveys conducted by the Ministry of Land, Infrastructure, Transport and Tourism to estimate the ratio of finished work () and the ratio of rework () in the cases where obtained results contain some kind of error. The calculation results thus obtained were =0.5505 and =0.4495 for work activities related to the estimation of the area flooded because of natural damming and =0.5519 and =0.4481 for work activities related to the estimation of the time of occurrence of a natural dam break.