STUDY OF EVACUATION TIME CHARACTERISTICS COUPLED WITH NUMERICAL SIMULATION OF TSUNAMI IN OKAYAMA CITY

Abstract

 Southern part of Okayama city is a low elevation area and has a great risk of liquefaction. Therefore coastal dike may possible subside due to the Nankai Trough earthquake and inundation just after quake is supposed to occur. In this study, we predicted the process of inundation in Okayama city caused by the dike subsidence, using the tsunami simulator that reproduced the layout of the city area in detail. Furthermore, evacuation routes and time to designated evacuation sites were evaluated by using the walking speed under the flooding conditions. The results show that many evacuation routes are changed by the inundation on the roads and the evacuation time of senior person becomes 1.6 times on average. This suggests that it is important for the evacuation planning to consider the water depth and the flow speed on the road. The present model is useful to investigate the evacuation time characteristic under the inundation conditions.