EVALUATION OF UNDERGROUND SPACE FOR TSUNAMI EVACUATION SAFETY WITH ROUTE OBSTACLES BY AGENT-BASED SIMULATION
Keywords:Evacuation simulation, Large-scale underground mall, Flooding, Evacuation guidance plan, Tsunami
In the Great East Japan Earthquake 2011, a massive tsunami that exceeded predictions caused extensive flooding damage over a widespread area. As a result, the managers of underground facilities in areas at risk of tsunami arrival prepare and publish evacuation safety plans detailing measures that will ensure smooth and rapid evacuations from their facilities in the event of a tsunami. However, when attempting to verify whether all affected persons can evacuate safely in the case of a major earthquake-related tsunami, it is necessary to consider various route obstacles that may result when the disaster first strikes. This study quantitatively evaluates the safety of an evacuation guidance plan created for a large underground facility in preparation for the flooding that would result from earthquake-related tsunamis and examines the effects of evacuation route obstacles via simulations. The main findings are as follows: By comparing the results with the evacuation safety plan prepared by the facility management company and the results of simulation of each scenario including accidents, we could evaluate safety impacts quantitatively. In some scenarios, the evacuation completion time was delayed by more than 1.5 times compared to the scenario by the management company due to the high concentration of evacuees on the stairs caused by obstacles in the evacuation route. The scenarios in this study showed that evacuation time impacts were more severe in cases involving blocked corridors than in cases involving blocked stairways.