Japan Geoscience Union Meeting 2014

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Oral

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

[M-IS23_2AM1] tsunami deposit

Fri. May 2, 2014 9:00 AM - 10:45 AM 415 (4F)

Convener:*Kazuhisa Goto(International Research Institute of Disaster Science (IRIDeS),Tohoku University), Masanobu Shishikura(Active Fault and Earthquake Research Center, GSJ/AIST), Yuichi Nishimura(Graduate School of Science, Hokkaido University), Chair:Kazuhisa Goto(International Research Institute of Disaster Science (IRIDeS),Tohoku University)

9:45 AM - 10:00 AM

[MIS23-04] Scour and deposition by the 2011 Tohoku-oki tsunami at Takata-matsubara in Rikuzentakata City, Japan

*Yasuhiro TAKASHIMIZU1, Takahiro SHIBUYA2 (1.Faclty of Education, Niigata University, 2.Graduate school of Education, Niigata University)

Keywords:tsunami deposits, Rikuzentakata City, shooting flow, hydraulic jump, Takata-matsubara, Seawall

The behavior of the 2011 Tohoku-oki tsunami at the Takata-matsubara in Rikuzentakata city was reconstructed using sedimentary facies analysis, grain size properties and magnetic fabric were summarized as follows;1) Vertical variations in grain size of the tsunami deposits show ten and several tsunami inflows and outflows of the tsunamis. 2) The deposits were mainly formed by backwash of the tsunami based on the paleocurrent analysis using magnetic fabric measurements.3) The tsunami flow over the artificial sea wall and destroyed the sea wall with large scours on ground surface. Following ten and several tsunamis with minor wave height can ran-up in order to destroying the sea wall.