Japan Geoscience Union Meeting 2019

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[J] Oral

H (Human Geosciences ) » H-DS Disaster geosciences

[H-DS14] Geohazards in humid, tectonically active countries and their precursors

Mon. May 27, 2019 10:45 AM - 12:15 PM 106 (1F)

convener:Masahiro Chigira(Disaster Prevention Research Institute, Kyoto University), Hiroshi YAGI(Faculty of Art, Science and Education, Yamagata University), Satoru Kojima(Department of Civil Engineering, Gifu University), Taro Uchida(National Institute for Land and Infrastructure Management), Chairperson:Satoshi Ishimaru

11:30 AM - 11:45 AM

[HDS14-04] Slope failures occurred in the southwest part of the Izu-oshima Island in geological time, NE Japan

*Takehiko Suzuki1, Masahiro Chigira2 (1.Faculty of Urban Environmental Sciences, Tokyo Metropolitan University, 2.Disaster Prevention Research Institute, Kyoto University)

Keywords:Slope failure, Tephric soil deposits, Izu-oshima Island

So-called “loam” composed of primary fall-out tephras and tephric soil deposits (tephric loess) is one of the factors cause earthquake-induced landslide. To evaluate potential of slope failure by this combination in the Japanese Island, earthquake-induced landslides potential assessment should be examined in relevant areas, considering frequency of landslides in geological time. To estimate this, we examined unconformities within “loam” on the Izu-oshima Island, Tokyo, where thick loam has been formed during last 19 ka. We identified at a maximum six unconformities suggesting possibility of occurrences of landslides during the period between 19-1.8 ka.