JpGU-AGU Joint Meeting 2020

Presentation information

[J] Poster

H (Human Geosciences ) » H-DS Disaster geosciences

[H-DS12] Geohazards in humid, tectonically active countries and their precursors

convener:Satoru Kojima(Department of Civil Engineering, Gifu University), Hiroshi YAGI(Faculty of Art, Science and Education, Yamagata University), Taro Uchida(University of Tsukuba), Yoshihiko Kariya(Department of Environmental Geography, Senshu University)

[HDS12-P01] Geomorphological and geological details of the Mizore large-scale landslide and its causal link to AD1586 Tensho Earthquake in Gifu Prefecture, central Japan

★Invited Papers

*Takahiro Kurimoto1, Yoshihiko Kariya2, Kuniyasu Mokudai3, Ryuji Yamada4, Takashi Kimura5, Masaki Sano6, Akane Tsushima7, Zhen Li8, Takeshi Nakatsuka8 (1.Graduate student , Senshu Univ., 2.Senshu Univ., 3.Tohoku Gakuin Univ., 4.NIED, 5.Ehime Univ., 6.Waseda Univ., 7.MRI, 8.Nagoya Univ.)

Keywords:AD1586 Tensho-earthquake, Shokawa fault zone, Large-scale landslide, Dammed lake, Paleo-earthquake

A large-scale landslide (V=2.2×107 m3) called the ”Mizore-no Oware(landslide)“ is present around the southern tip of Shokawa-active fault zone. ML is believed to be caused by the AD1586 Tensho-earthquake (est. M 7 to 8 ) based on historical documents. However, a few researches regarding geological and geomorphological characteristics of ML have been carried out. Based on field investigation and geomorphological analysis by using GIS, we clarified the geological and geomorphological features of ML. The main conclusions are as follows.; a) The ML holds a set of three dissected head scarps and three landslide bodies both showing multiple landslide events. ; b) The ML shows unique geological and geomorphological features such as a jigsaw crack structure and “patchwork structure” in the landslide materials and hummocks/depression upon the ground surface of the landslide bodies; c) Materials of landslide body involve paleosol and fossil logs that enable us to date the landslide event; d) According to 14C dates of logs in paleosol, the latest landslide event is likely occur cal AD1493-1645; e) Also, one wood log sampled from dammed-lake deposits indicated cal AD 1514 to 1618 by 14C and AD1615 to 1620 by tree-ring 18O methods; f)The latest landslide event should be triggered by AD1586 Tensho-earthquake (estimated M=7 to 8) generated from the Shokawa fault zone close to northern of ML.