Japan Geoscience Union Meeting 2019

Presentation information

[J] Poster

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS12] tsunami deposit

Thu. May 30, 2019 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall8, Makuhari Messe)

convener:Takashi Chiba(Faculty of Bioresource Sciences, Akita Prefectural University), Tetsuya Shinozaki(Center for Research in Isotopes and Environmental Dynamics (CRiED), University of Tsukuba), Daisuke Ishimura(Department of Geography, Tokyo Metropolitan University)

[MIS12-P03] Investigation of event deposits for construction of tsunami deposit discriminating method

*Shiro Tanaka1, Takumi Yoshii1, Yasuto Hirata1, Takaomi Hamada1, Masafumi Matsuyama1, Yuki Ito1 (1.Central Research Institute of Electric Power Industry)

Keywords:tsunami deposit, debris flow deposit, storm surge deposit

In order to establish a method to certify tsunami deposit, we investigated event deposits not due to the tsunami to be compared. Targets of survey are debris flow deposits due to torrential rains in Chugoku region in July 2018 and storm deposits due to September No.21 typhoon in Kansai region. Major survey points are debris flow generated at the slope facing the Hiroshima International University, debris flow generated behind JR Mizushiri Station, and debris flow generated on the upstream slope of JR Yano station in Hiroshima Prefecture. Debris flow deposits are distinguishable from tsunami deposits since they are mainly composed of huge rock masses near the source. On the other hand, at the end of the debris flow, it becomes a deposit having a layer structure mainly composed of sand size particles. Therefore, in this survey, we investigated and sampled deposits at the end of the debris flows. Surveys of storm surge deposits were conducted at Ashiyahama Beach and Omaehama Park in Hyogo Prefecture and at Nishikinohama Beach in Osaka Prefecture. The survey was conducted about 10 days after the storm surge occurrence, it was difficult to collect storm deposits at the Ashiyahama Beach and the Omaehama Park, but deposits possibly formed by storm surge could be collected at the Nishikinohama Beach. In the presentation, we will introduce mainly the particle size distribution of these deposits.