Japan Geoscience Union Meeting 2016

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Oral

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

[M-IS11] tsunami deposit

Thu. May 26, 2016 9:00 AM - 10:30 AM IC (2F)

Convener:*Kazuhisa Goto(International Research Institute of Disaster Science (IRIDeS),Tohoku University), Masanobu Shishikura(Institute of Earthquake and Volcano Geology, National Institute of Advanced Industrial Science and Technology), 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

[MIS11-04] Behavior of the 2011 Tohoku-oki tsunami using magnetic fabric

*Yasuhiro Takashimizu1, Yuka Hatori1, Atsushi Urabe1, Yoshihiro Kase2, Keiichi Hayashi2 (1.Niigata University, 2.Geological Survey of Hokkaido, Hokkaido Research Organization)

Keywords:magnetic fabric, tsunami deposits, anisotropy of magnetic susceptibility, the 2011 Tohoku-oki tsunami

Behavior of the 2011 Tohoku-oki tsunami was reconstructed using magnetic fabric. First, a plane bed was formed using experimental flume in order to verify the effectiveness of the magnetic fabric, and it is confirmed that the current direction estimated using magnetic fabric is the same direction of flow in the flume. Then, field survey and facies descriptions of the deposits were conducted in Odaka area, Minami-Soma city, Japan. The deposits were divided into three sedimentary units based on facies descriptions and magnetic fabric data. Unit 1 is of medium-grained sand including abundant mud clasts and is interpreted to inflow deposits. Unit 2 consists of parallel laminated medium-grained sand deposited under return flow of the tsunami. During the final and/or post tsunami period, organic silt (Unit 3) was accumulated from stagnant water caused by the tsunami.