Clinical Features of Disaster-Associated Direct Deaths during Recent Inland Earthquakes in Japan

Natural disasters, including earthquakes, cause disaster-associated direct deaths due to hazards and disaster-related deaths. This study was a retrospective and observational study that explored the effect of natural disasters on direct death. Although research reports on disaster-related deaths are common, there are few reports of disaster-associated direct death caused by events, such as house collapses, fires, and sediment-related factors. The amendment of the Building Standards Law in 1981 has made Japanese building standards more stringent. We sought to examine the determinants of the number of disaster-associated direct deaths during recent inland earthquakes in Japan. Following 2016 Kumamoto earthquakes (April 14, 21:26 [magnitude (M) 6.5], April 15, 0:03 [M 6.4], and April 16, 1:25 [M 7.3] and the subsequent numerous aftershocks), police necropsies confirmed 50 disaster-associated direct deaths (28 women [56%]). Thirty-four victims (68%) were elderly people 65 years of age or older, and 38 victims (76%) died as a result of a collapsed house. These percentages are consistent with those associated with recent inland earthquake disasters in Japan. The main finding was a linear correlation between the number of completely collapsed houses and the number of deaths due to house collapse during recent inland earthquakes in Japan (P = 0.02). It is suggested that the maintenance of houses may be important in reducing the number of disaster-associated direct deaths during inland earthquakes. The amendment of the Building Standards Law might reduce the number of disaster-associated direct deaths during inland earthquakes.