JpGU-AGU Joint Meeting 2017

Presentation information

[JJ] Oral

H (Human Geosciences) » H-CG Complex & General

[H-CG37] [JJ] Active fault and disaster mitigation learned from 2016 Kumamoto earthquake

Sun. May 21, 2017 10:45 AM - 12:15 PM A02 (Tokyo Bay Makuhari Hall)

convener:Yasuhiro Suzuki(Nagoya University), Hiroyuki Fujiwara(National Research Institute for Earth Science and Disaster Prevention), Yoshiaki Hisada(Kogakuin University, School of Architecture), Toshitaka Kamai(Disaster Prevension Research Institute, Kyoto University), Chairperson:Yoshiaki Hisada(Kogakuin University, School of Architecture), Chairperson:Yasuhiro Suzuki(Nagoya University)

12:00 PM - 12:15 PM

[HCG37-16] Modeling of the subsurface structure from the seismic bedrock to the ground surface for a broadband strong motion evaluation during 2016 Kumamoto earthquake.

*Shigeki Senna1, Kaoru Jin1, Atsushi Wakai1, Hiroki Azuma1, Shohei Naito1, Nobuyuki Morikawa1, Takahiro Maeda1, Asako Iwaki1, Ryuji Yamada1, Shinichi Kawai1, Hisanori Matsuyama2, Hiroyuki Fujiwara1 (1.National Research Institute for Earth Science and Disaster Prevention, 2.OYO Corp)

Keywords:Strong motion evaluation, S-wave velocity structure model, Microtremor array, Borehole data, Predominant period

On April 16, 2016, a Japan Metrological Agency Magnitude (MJMA) 7.3 earthquake struck the Kumamoto Prefecture on the island of Kyushu in southwest Japan. This earthquake followed the MJMA 6.5 earthquake, which struck on April 14. Both the earthquakes registered a reading of 7 on the Japan Metrological Agency seismic intensity scale (IJMA), which is the highest reading on the IJMA, in the town of Mashiki approximately 6.5 and 5.5 km from the hypocenters of the main shock and foreshock, respectively.

The tendency damage is concentrating at the earthquake fault neighborhood confirmed the building damage distribution. However, even if damage is away from a little location and the fault even if it's right above the gap, the location where damage is big relatively is also confirmed. There is also comment with a high possibility caused by soil structure for these phenomena. We put it around Kumamoto plain in the fault neighborhood, collected borehole data and built initial stage geologic model, and a microtremor observation and seismography record were collected.

And secondary S-wave velocity model built highly precise ground model and did comparison and consideration with the building damage distribution.
This research was conducted by SIP (Cross-ministerial Strategic Innovation Promotion Program), “reinforcement of resilient disaster prevention and mitigation function” of Council for Science, Technology and innovation.