The Importance of Seismic Death Risk Assessment of Households in the Kumamoto Earthquake of 2016
Tadayoshi Nakashima†, Shigeyuki Okada, and Akane Shinoda
Kita 13 Nishi 8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan
This paper discusses the reduction effect of a foreshock on casualties during the mainshock of people who evacuated to shelters and their private cars during the 2016 Kumamoto earthquake. In the first part of this paper, we discuss the number of human casualties caused by the collapse of wooden buildings. The characteristics of casualties in the Kumamoto earthquake are classified as household attributes and building damage caused by the foreshock and mainshock. In the second part, we apply equations (Nakashima and Okada 2008 and Okada and Nakashima 2015) to the Masiki area to determine the total number of casualties with a focus on deaths. The number of deaths due to total building damage from the foreshock and the mainshock in the case of 0 evacuees was estimated as 147. We then estimated the reduction effect on the number of casualties caused by the foreshock by using the survey data of the mainshock and foreshock. We found that evacuation during the mainshock decreased the death toll by 128 people. Moreover, the number of injured people decreased by 657. Generally, most people who evacuate tend to return home over time. As a result, many people die at the time of a subsequent mainshock. It is important to provide death risk information to each household to support their decision-making regarding appropriate evacuation.
-  Kumamoto Prefecture, “Preliminary Reconnaissance Report of Damages by the Kumamoto Earthquake (247th Report),” Jul. 13, 2017 (in Japanese).
-  M. Sugino, R. Yamamuro, S. Kobayashi, S. Murase, S. Ohmura, and Y. Hayashi, “Analyses of Building Damages in Mashiki Town in the 2016 Kumamoto Earthquake,” J. of Japan Association for Earthquake Engineering, Vol.16, No.10, pp. 69-83, 2016 (in Japanese with English abstract).
-  M. Ushiyama, Y. Saki and K. Sugimura, “Characteristics of victims of the 2016 Kumamoto Earthquake,” J. of Japan society for natural disaster science, Vol.35, No.3, 2016 (in Japanese with English abstract).
-  National Institute for Land and Infrastructure Management Ministry of Land, Infrastructure, Transport and Tourism, Japan and Building Research Institute National Research and Development Agency, Japan, “Quick Report of the Field Survey on the Building Damage by the 2016 Kumamoto Earthquake,” Sep. 2016 (in Japanese).
-  S. Okada and T. Nobuo, “Classifications of Structural Types and Damage Patterns of Buildings for Earthquake Field Investigation,” J. of structural and construction engineering, Trans. of AIJ 524, pp. 65-72, 1999 (in Japanese with English abstract).
-  S. Okada and T. Nakashima, “A New Causality Model for Evaluating the Probability of Human Damage from Injury to Death Associated with Building Collapse,” in K. Ohtsuka (Ed.), “Health and Labour Sciences Research Grant report,” pp. 147-161, 2015 (in Japanese).
-  National Police Agency, “Information on Killed Victims by the 2016 Kumamoto Earthquake,” announced in Apr., pp. 15-16, 2016 (in Japanese).
-  ZENRIN, “Residential Maps in Mashiki Town,” Nov. 2014 (in Japanese).
-  K. Kenji and K. Tanaka, “Complete Enumeration in Urban Area of Mashiki Town,” Disaster Investigation Report Meeting, pp. 83-93, Aug. 2016 (in Japanese).
-  Geographical Survey Institute of Japan, “Information on the Kumamoto Earthquake of 2016,” (in Japanese), http://www.gsi.go.jp/BOUSAI/H27-kumamoto-earthquake-index.html#2 [accessed Jul. 27, 2017]
-  Statistic Bureau, Ministry of Internal Affairs and Communications, “Census Data in 2010,” (Grid Square Statistics) (in Japanese).
-  NHK Broadcasting Culture Research Institute, “Report on Time Use Research in 2015,” Feb. 2016 (in Japanese).
-  S. Takuma, H. Fujiwara, K. Sakamoto, and N. Yoshii, “A Consideration about Estimation of the Number of Dead by an Earthquake using Damage Information which Paid Attention to Structural Damage in Buildings,” Summaries of Technical Papers of Annual Meeting, pp. 481-482, 2017 (in Japanese).
-  T. Nakashima and S. Okada, “Seismic Strengthening Strategy for Wood Frame Dwellings Targeting to Minimize the Death Toll from a View Point of Temporal Variation – Case Study for Tokai Region, Japan, in the Forthcoming Tokai-Tohnankai Earthquake –,” J. of Structural and Construction Engineering, Vol.73, No.623, pp. 79-86, 2008 (in Japanese with English abstract).
-  Statistic Bureau, Ministry of Internal Affairs and Communications, “The 2013 Residence and Land Statistics,” (in Japanese).
This article is published under a Creative Commons Attribution-NoDerivatives 4.0 Internationa License.