Impacts of disaster mitigation/prevention urban structure models on future urban thermal environment

The possibility of a huge earthquake and the following disasters, such as tsunami and ground liquefaction, in the near future has been pointed out in the third largest metropolitan area (Nagoya metropolitan area) in Japan. In the region including the Nagoya metropolitan area, a huge earthquake of magnitude 8 class has occurred every 100-150 years. The last huge earthquake in the region happened in 1944. Therefore, the viewpoint of disaster mitigation/prevention against an expected huge earthquake is crucial for future urban planning in the Nagoya metropolitan area. On the other hand, the population in the Nagoya metropolitan area is expected to decrease in the future. Such a decrease in population usually leads to a reduction of the urban area. In this study, three disaster mitigation/prevention urban structure models were designed for future urban planning of the 2050s (the target period in which about 100 years will have passed since the last huge earthquake) in the Nagoya metropolitan area considering a reduction in the urban area according to a projected decrease in population. Subsequently, the impacts of the introduction of the three disaster mitigation/prevention models, i.e., (1) a tsunami damage mitigation/prevention model, (2) a strong motion damage mitigation/prevention model, and (3) a ground liquefaction damage mitigation/prevention model, on the future (the 2050s) thermal environment were quantitatively investigated using a regional atmospheric model, the Weather Research and Forecasting (WRF) model. Moreover, an urban structure model that combined the three disaster mitigation/prevention models was constructed, and the effect of the combined model on the future thermal environment was also evaluated.