Japan Geoscience Union Meeting 2014

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Symbol H (Human Geosciences) » H-DS Disaster geosciences

[H-DS28_1PO1] Earthquake, Tsunami and Volcanic Eruption Hazards and Risks in Asia-Pacific Region

Thu. May 1, 2014 6:15 PM - 7:30 PM Poster (3F)

Convener:*Takarada Shinji(Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology), Naoji Koizumi(National Institute of Advanced Industrial Science and Technology, Active Fault and Earthquake Research Center, Geological Survey of Japan), Yasuto Kuwahara Yasuto(National Institute of Advanced Industrial Science and Technology), Yuzo Ishikawa(The National Institute of Advanced Industrial Science and Technology), Akira Takada(National Institute of Advanced Industrial Science and Technology Geological Survey of Japan), Ryuta FURUKAWA(Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology), Norio Shigematsu(Active Fault and Earthquake Research Center, Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology), Tadashi Maruyama(Ministry of Education, Culture, Sports, Science and Technology)

6:15 PM - 7:30 PM

[HDS28-P01] Influence of mircotopography in lowland to tsunami disaster of 2011 Tohoku Earthquake

*Kazuya IKARI1, Chiyuki NARAMA2 (1.Graduate School of Science & Technology, Niigata University, 2.Faculty of Science, Niigata University)

Keywords:2011 Tohoku Earthquake, tsunami, Sendai Pliain, lowland, mircotopography, aerial-photographs

The earthquake (magnitude 9.0) on Mar 11, 2011 in Tohoku, Japan triggered the terrible destructive tsunami, striking the eastern coastal region of Japan. Although residents in valley bottom plain of the Sanriku Coast (ria coast) have a refuge area around hills, residents in Sendai Plain (meander plain of lowland) had to go to inland in order to escape tsunami. The lowland such as Sendai Plain is very vulnerable to tsunami. However, Building damages differed among the Sendai Plain. This study evaluated the influence of landform in lowland of Sendai Plain to tsunami disaster.The Sendai plain is meander plain of lowland (0-3m asl.), including beach ridges and inter-ridge march of ridged beach plain, and natural levees along present and mender scars.Three beach ridges are developed along the coast. Relative height of present beach ridge is 3-5m, and inner two beach ridges are 1-2m.We classified three damage-categories (flow out, destroy, and remain) to individual buildings in tsunami inundation area of the Sendai Plain, based on interpretation of aerial-photographs on 2011 and Google Earth satellite image 2012.In addition, we made a GIS data of utility pole, flattened tide protection forest, driftwood, tsunami scratch in Sendai Plain, to know flow directions of tsunami and distribution of woods.Building damages in the Sendai plain show >80% of buildings flowed out within 1km area from the coast. Remaining buildings are located on ridged beaches with 1-2m high. Driftwood and rubble had stopped on the near side of beach ridges and highway embankment. Tsunami flow was concentrated in the inter-ridge march or small stream channels. Around the Abukuma River, buildings under cut slope received tsunami damage, and slip-off slope side was safety. In lowland plain, we clarified microtopography with 1-2m relative height reduced tsunami damages around inland side area (>1km) from the coast.