The objective of this report is to state the topography, underground structure as well as the motion properties of largescale deep rock slides in the TERTIARY GREEN TUFF region, using the Takisaka landslide as a model testing area. The results areas follows;
1) Based upon the analysis of the moving quantity obtained by aerial photogrammetry, the Takisaka landslide can be roughly separated into a northern region and a southern region with respect to Sekizawa, and the slope motion type in the southern region corresponding to a planner slide type landslide.
2) The landslide boundary portion and block group are limited by faults.
3) The sliding surface shapes in the main measurement line are not limited by the ascent slope structure, and have a very low angle through the fracture bed of GREEN TUFF existing as a dip slope condition, which look like as boat shaped. In the course of the investigation of the sliding surface, effective use was made of the detectors of sliding surface and sinker method.
4) The movement was mainly made in the snowelt season, and sliding distance strongly correlates with the maximum snow cover depth of snowmelt season. Furthermore, changes in the moving quantity correspond sensiblely with those of the groundwater table.
5) The movement is similar to a creep type and is in accordance with the results of the examination of the soil properties of the fracture bed of GREEN TUFF in Sodenosawa which has a sliding surface.

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