Japan Geoscience Union Meeting 2016

Presentation information

Poster

Symbol M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS34] The 2016 Kumamoto Earthquake and related crustal activities

Thu. May 26, 2016 3:30 PM - 4:45 PM Poster Hall (International Exhibition Hall HALL6)

5:15 PM - 6:30 PM

[MIS34-P81] Real-time Damage Estimations for the 2016 Kumamoto Earthquakes by J-RISQ

*Hiromitsu Nakamura1, Hiroyuki Fujiwara1, Yoshinori Homma2 (1.National Research Institute for Earth Science and Disaster Resilience, 2.Mitsubishi Space Software Corporation)

Keywords:Kumamoto earthquake, J-RISQ, real-time damage estimation

The National Research Institute for Earth Science and Disaster Resilience (NIED) is developing a real-time earthquake information system for damage estimation and situation assessment (J-RISQ) as a Cross-ministerial Strategic Innovation Promotion Program (SIP).J-RISQ is able to immediately estimate earthquake damage by combining methods for predicting ground motion using amplification characteristic data for subsurface ground, basic information on population and buildings, damage assessment methods for buildings using fragility functions, and observation data such as real-time strong motion data obtained by K-NET, KiK-net, local governments, and JMA. A part of J-RISQ information (including the estimated distribution of seismic intensity and the population exposed to each seismic intensity level) is published as a “J-RISQ Report” on http://www.j-risq.bosai.go.jp/ immediately after the occurrence of an earthquake. In this study, we describe the estimations by J-RISQ for the 2016 Kumamoto earthquakes (M6.5 event and M7.3 event) with maximum seismic intensity of 7 caused great damage to human beings, buildings, and infrastructures.
J-RISQ issued the first report 29 seconds after the M6.5 event occurred and a total of seven reports for about 10 minutes. The first report using data from 5 stations showed that population exposed to seismic intensity 6 lower or larger was 7,800. Finally the system estimated that population exposed to seismic intensity of 6 lower or larger was 620,000 and that of 6 higher or larger was 290,000 by using 1091 strong motion data. The estimated results of building damage showed that completely destroyed buildings were between 6,000 and 14,000 and partly destroyed were between 7,000 and 33,000. The distribution of estimated completely destroyed buildings spread 7 km long by 1 km wide in Mashiki town.
For the M7.3 event occurred about 28 hours after the M6.5 event, the system distributed the first report 29 seconds after the M7.3 event occurred and a total of eight reports for about 11 minutes. Finally the system estimated that population exposed to seismic intensity of 6 lower or larger was 1,130,000 and that of 6 higher or larger was 670,000 by using 2391 strong motion data. The estimated results of building damage showed that completely destroyed buildings were between 16,000 and 38,000 and partly destroyed were between 18,000 and 88,000. The distribution of estimated completely destroyed buildings spread in Mashiki town similar to the result of the M6.5 event and Kumamoto city. However, this result of damage building is out of consideration of the effect of the earthquakes including M6.5 event before M7.3 event. At this time, we are not able to compare these results with real damage because the whole picture of real damage has not been grasped yet. A detailed analysis of real damage is to be desired.

Acknowledgements
This work was supported by the Council for Science, Technology and Innovation (CSTI) through the Cross-ministerial Strategic Innovation Promotion Program (SIP), titled ``Enhancement of societal resiliency against natural disasters'' (Funding agency: JST). The seismic intensity data from local governments and JMA that were used in the real-time system were provided by JMA.