Hiroshima has the highest risk of sediment disaster in Japan. On 20th August 2014, heavy rainfall during the night caused sudden debris flows at various sites in Hiroshima city, which resulted in a large number of casualties. Extreme rainfall during the few hours before the landslides caused muddy streams in front of residentsʼ homes, preventing them from escaping. The city heavily invested in disaster prevention measures after this experience, including research into the mechanism of sediment transport to mitigate the impact. However, in July 2018, Hiroshima citizens suffered another calamity from debris flows. This study examines the testimony given by the victims of the ʻ8.20 Hiroshima disasterʼ to clarify their perceptions of the disaster and how they wish to communicate it in their own words.
Testimonies by 145 victims were analysed using text-mining analytics and linguistic discourse analysis. The results reveal a set of previously unknown facts-namely, how the residents of the affected areas perceived the disaster while it was unfolding before their eyes.
The testimony contents are divided into four categories: (1) Physical aspects of the disaster such as natural phenomena and impact on infrastructure; (2) Impressions of how the disaster developed; (3) Peopleʼs behaviour before, during, and after facing the natural phenomenon; (4) Psychological impacts of the disaster before, during, and after facing the natural phenomenon.
The empirical results reveal that peopleʼs subjective perceptions are a key factor in decision-making when faced with an impending natural disaster. Thus, we argue that both physical and psychological aspects need to be considered in supporting the residents of high-risk areas in order to prevent future sediment disasters.