Large Sediment Movement Caused by the Catastrophic Ohya-Kuzure Landslide
Satoshi Tsuchiya* and Fumitoshi Imaizumi**
*Faculty of Agriculture, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka-shi, Japan
**Ikawa University Forest, University of Tsukuba, 1621-2 Ikawa, Aoi-ku, Shizuoka-shi, Japan
The Ohya-kuzure landslide, one of three largest catastrophic landslides in Japan, is assumed to have been triggered by a strong earthquake and a large-scale debris terrace in a channel downstream from landslide. We verified the time of the landslide’s occurrence, its volume, and the amount of sediment supplied to the main river downstream. The landslide’s occurrence in 1707 was confirmed by historical documents and earthquake records of sediment disasters. The landslide’s size was estimated to be 94 million m3, from the geomorphic change in the debris terrace. Moreover, it was presumed that 33% of the sediment accumulating as a debris terrace (29 million m3) was eroded, and that a sediment volume of 17 million m3 was supplied to the upstream region of the main river. Small-scale debris flows have been triggered recently in the source head of the landslide during heavy annual rainfalls. In 2006, a debris flow in Ichinosawa tributary with the most vigorous debris production and transport in the landslide was recorded during a typhoon. Hydrographs of the debris flow quantified by ultrasonic sensor and hydraulic pressure sensor supplemented video images.
-  O. Guogiang, S. Kobashi, and T. Mizuyama, “Prediction of Debris Flow Peak Discharge,” J. of Japan Society of Erosion Control Engineering, Vol.44, No.4, pp. 24-29, 1991 (in Japanese).
-  A. Ikeda, N. Monma, S. Horiuchi, and T. Yamada, “Debris Flows Generated in Kitamata Valley of the Name River,” J. of Japan Society of Erosion Control Engineering, Vol.51, No.2, pp. 31-38, 1998 (in Japanese).
-  F. Imaizumi, S. Tsuchiya, and O. Ohsaka, “Behaviour of Debris Flows Located in a Mountainous Torrent in the Ohya Landslide, Japan,” Canadian Geotechnical J., Vol.42, pp. 919-931, 2005.
-  H. Machida, “On the Accumulation Terraces Along the Upper Reaches of the River Abe,” Geographical Review of Japan, Vol.32, pp. 520-531, 1959 (in Japanese).
-  “History of Erosion Control in Abe River,” Shizuoka River Officer, Ministry of Construction, 1988 (in Japanese).
-  H. Suwa and K. Okunishi, “Motion, Debris Size and Scale of Debris Flow in a Valley on a Mt. Yakedake Japan,” Annuals of Disaster Prevention Research Institute, Kyoto University, Vol.33B, No.1, pp. 191-203, 1990 (in Japanese).
-  T. Takahashi, “Debris flow,” IAHR Monograph, London, Taylor & Francis, 1991.
-  T. Takahashi, “A Mechanism of Occurrence of Mud-Debris Flows and Their Characteristics in Motion,” Disaster Prevention Research Institute, Annuals, No.20B-2, pp. 404-436, 1977 (in Japanese).
-  “Report of the effect on the mountainous conservation works in the Abe River district,” Tokyo Regional Forest Office, pp. 83-84, 1975 (in Japanese).
-  R. Tsuchi, “Geological Map of Shizuoka Prefecture, Scale 1:200,000,” Tokyo, Naigaichizu, 2001.
-  R. Tsuchi, “Guide of Geoscience, Shizuoka Prefecture,” Tokyo, Corona, 1992 (in Japanese).
-  S. Tsuchiya, M. Kimura, O. Ohsaka, and M. Tarumi, “Debris Transport on the Steep Gully of the Mountainous Large-Scale Ohya Collapse, Shizuoka Prefecture, Japan,” INTERPRAEVENT 1996, Garmish-Partenkirchen, Band 1, pp. 273-262, 1996.
-  “History of Umegashima Village,” Umegashima Board of Education, 1968 (in Japanese).
-  T. Usami, “Materials for Comprehensive List of Destructive Earthquakes in Japan,” Tokyo, University of Tokyo Press, 1996 (in Japanese).
This article is published under a Creative Commons Attribution-NoDerivatives 4.0 International License.