Ryo Nakamura

Study on Flood Evacuation Behaviors through Information Sharing Using Message Apps

Yoko Matsuda

Surveys from past flood cases have shown that even if general countermeasures are taken, people may not evacuate unless they are given information that prompts them to take evacuation action, such as evacuation orders or calls from neighbors. Therefore, it is important to quantitatively evaluate what kind of information triggers people to evacuate during floods.
In this study, we focused on information sharing using a message application that can quickly share information with many people, and conducted a survey in a neighborhood association in Nagaoka City to understand the current use of the message application (LINE) system. Then, we conducted a web survey and used the visual analogue scale (VAS) method to quantitatively evaluate evacuation intentions on “evacuation instructions”, “neighborhood conversation," "river images," "water gauge graph," and "rain cloud radar" were presented on the message application. In addition, the hypothesis that residents' conversation on a message application affects to raise evacuation intention is tested.
A survey conducted by the Nagaoka City Settaya 5-chome Neighborhood Association on the introduction of a message application (LINE) system showed that using a message application to communicate information within the community would reduce time and enable accurate sharing of information, thereby reducing risk and burden in the event of flooding. However, there were a certain number of households in the community in which none of the members of the household were using LINE, suggesting the need for coordinated efforts such as the use of circulars and calls for evacuation.
The results of the quantitative measurement of evacuation intention from the web survey showed that among the five types of information presentation screens, river images tended to increase the evacuation intention to a certain degree for various respondent attributes, while rain cloud radar did not contribute to increasing the evacuation intention. The effect of the residents' conversation was verified, and it was revealed that the information presentation screen of the residents' conversation contributed more to the evacuation intention than the information presentation screen of the evacuation order from the local government. It was also estimated that the intervention of the residents' conversation increased the intention to evacuate.