Classification of tsunami deaths by modifying ICD-10 categories in the 2011 Tohoku earthquake tsunami - A case study in Miyagi prefecture

The 2011 Great East Japan Earthquake had a tremendous impact in terms of human suffering in Japan. To date, drowning has been considered the primary cause of death in the context of tsunami disasters. According to Japan's National Police Agency [9], causes of death other than drowning were also indicated, including due to fire and traumatic shock. Given the reports of deaths from causes other than drowning in the 2011 GE JE, a need to summarize these deaths in a statistical manner and systematize them according to the actual situation was perceived. To that end, in this study, we examined victim data from the 2011 GEJE provided by the Miyagi Prefecture Police Headquarters with reference to the International Statistical Classification of Diseases and Related Health Problems to investigate a classification method that would reflect the actual situation of this event. Using this classification method, we attempted to analyze the actual situation with regard to causes of death in all of Miyagi Prefecture during the 2011 GEJE. Consequently, the following five classification methods were proposed: (1) aggregate a cause of death into one higher category in the ICD-10, (2) aggregate what can be forensically determined to be the same cause of death, (3) aggregate a cause of death by combining the two methods above, (4) aggregate unknown causes, and (5) aggregate causes that do not fall into other categories. As a result of classification by these five methods, we classified the causes of death in Miyagi Prefecture into the twelve distinct categories.