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)

10:00 AM - 10:15 AM

[MIS11-05] Tsunami deposits in Holocene sediments on Shita Plain, Shizuoka, central Japan

*Akihisa Kitamura1 (1.Institute of Geosciences, Faculty of Science, Shizuoka University)

Keywords:Shita plain, Holocene, tsunami deposits

Geological coring in Hamatome lowland of the northern Shita plain, central Japan, revealed occurrence of two event deposits which composed of single or multiple graded beds with sharp erosional bases and 10–60-cm-thickness and represent the higher-energy hydrodynamic event. Radiocarbon dates show that two event deposits were deposited from AD 780 to AD 1025, and after AD1025, respectively. The lower event deposit overlies back marsh clay and in turn is overlain by backshore and beach ridge deposits, indicating that higher-energy hydrodynamic event was accompanied with rapid transgression. The correspondence between geological and historical records, we concluded that lower event deposit was caused by AD 887 Ninna tsunami and that the transgression was associated with submarine landslide and/or erosion by tsunami. The upper event deposit may be caused by AD 1498 Meio tsunami.