jaue2019-056: Analysis of actual situation of hazard map in 23 wards of Tokyo.

Abstract

There is a high risk of disaster in Tokyo 23 wards area where the earthquake and tsunami are expected to occur 
in the coming years, and the flood damages caused by heavy rain are also expected. In this study at first, flood 
hazard maps were investigated for the 23 wards of Tokyo to analyze how a hazard map is positioned and how it is 
developed, comparing with the hazard maps preparation guidelines established by the Ministry of Land, 
Infrastructure and Transport set. As a result of analyzing the hazard maps of 23 wards in Tokyo, it was found that 
the expression method is different in each 23 wards. In the event of flood damage, we found differences in 
inundation threshold, color classifications, shelters and evacuation directions. One of the causes is that the final 
decision of the preparation is entrusted to each district, so it can be mentioned that the unified hazard maps will not 
be completed even using the guidelines. The fact that the expression is different even though it is a single ward may 
cause confusion in the present situation where the place of residence and the place of work are different.