北海道,網走・北見・津別地域の地すべり(第2報) : 美幌地域での地すべり地形の特徴と最近の地すべり

概要

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In the topographic map "Bihoro"1 : 50，000 in scale situated in the central part of the Abashiri-Kitami-Tsubetsu landslide concentration region, 168 landslide configurations were recognized in aeria-photographs. Most of them are concentrated in the western area，which consists of siltstone and hard shale with interbeds of thin layers of tuff, the so-called Miocene Tsubetsu Formation. This is presumably related to the siltstone and shale which disintegrated into small fragments to mud by weathering and to the clayey tuff beds. Most of the landslide configurations show morphology of small scale debris slump (A type) and debris slide (C and F types) in this area. The directions of landslide debris movement are mostly ENE to ESE. 　　Moreover，landslide configurations are found sporadically along the boundary between Quaternary welded tuffs or the Bihoro Formation which is composed of gravel and sand, and overlying pumice flow deposits in the eastern area. In this area， most of them are small-scale debris slide (F type).　Since some recent landslide disasters were caused by the re-sliding of older landslide debris，it is necessary to care of landslide configurations at the planning and investigating stages of developments.
北見工業大学の論文