Spatial Distribution of Causes of Death in the 2011 Tohoku Tsunami at Ishinomaki City, Miyagi Prefecture

Abstract

To predict and suppress human casualty in a future tsunami disaster, it is crucial to analyze victim information from past disasters and clarify the causes of human casualty. Examining the causes of human casualty requires analyses that combine various hazard information and victim information in subregional units. This study aims to grasp the factors that caused human casualty during the Great East Japan Earthquake in 2011 using Miyagi Prefectural Police Headquarters’ victim information. Therefore, at Ishinomaki City, Miyagi Prefecture, we researched the spatial distribution of causes of death based on the victims’ addresses and the corpse location, as well as the occurrence factor of each cause of death. As a result, we obtain the following results. (1) The spatial distribution of victims based on the corpse location is more clearly related to the hazard than the victim’s address. In other words, it is proved that the detection site of the body is significant when examining the relationship between human casualty and hazards. (2) The hypothesis of each cause of death is verified based on the spatial distribution of each cause of death, hazard information, the victim’s age, and the date of detecting the body. As a result, it is suggested that drowning, death due to fire, and hypothermia are causes of death related to external forces. It is also suggested that hypothermia and heart disease are causes of death related to individual fragility. (3) Such a possibility showed that the cause of death could not be identified for death from unknown origin due to the bodies’ decay resulting from taking time to detect the dead bodies. (4) We propose a diagram of relationship between the causes of death and the occurrence of factors of death at Ishinomaki City. In the future, to generalize the relationship, it is considered that the same analysis will be required in the coastal municipalities of Miyagi Prefecture.