Examining the potential of natural disaster monuments as surrogate indicators for disaster hazards in Japan

Japan is prone to natural disasters because of its diverse topographical, geological, and climatic conditions. It is vital to gain a deeper understanding of disaster-prevention measures to mitigate these effects. One aspect of this understanding is the construction of natural disaster monuments to educate future generations about lessons learned from past disasters. This study focuses on the location and distribution of these monuments and examines their potential as surrogate indicators of disaster hazards. To achieve this, we employ a two-pronged approach. The first approach is to analyze the relationship between the location of disaster monuments and disaster hazards. It involves plotting the locations of monuments from a database and investigating the relationship between the disaster covered by each monument and the current hazard using a hazard map portal site. The second approach is to assess the potential for disaster hazard mapping based on the disaster monuments. It involves creating Voronoi maps based on the location of disaster monuments and applying them to the entire national land area. It produced a disaster hazard map for Japan, including areas with no disaster monuments. The results provide aggregate information on the relationship between the location of disaster monuments and disaster hazards and the effectiveness of the Voronoi diagram-based disaster hazard maps. In many cases, the current hazard at the location of disaster monuments still exists, and 70% of the areas around tsunami-related monuments are still exposed to tsunami hazards. Additionally, this study suggests that Voronoi maps are promising for disasters and can accurately represent specific disaster hazard areas.