Mt. Funagata and Izumigatake are strato volcanoes which had mostly developed during the Early and the Middle Pleistocene and then have been mainly denudated by large landslides. In this paper the author reports landslide types which occur in and around volcano, occurence condition and age of landslides in this area, and relationship between occurence age and regional historical development of landforms.
The results are summerized as follows.
In this area there are two types of landslide. One is a large scale and block-glide type, and the other is comparatively small scale and formed by sliding of thick lava bed and so on. And the former one has also two types. One is remaining its original geological structure uncrushed through process of divide, and the other is crushing its original structure and forming a microlandform, such as pressure ridge. In every case, caprock structure is obserbed. It is thought that one of the factors which results in differences of landslide process and landform in this area is characteristics of caprock, such as variety and thickness of rocks.
Concerning the occurence age of large landslide in this area, the primary activity is estimated about 30, 000-40, 000yr. B. P. and secondary one is about 20, 000-30, 000yr. B. P.. After 10, 000yr. B. P., a considerable large one occured. During 30, 000-40, 000yr. B. P., the latest valleyfilling was replaced by downcutting in river terraces of mountain area of Tohoku district. And large landslide can easily be expected to occur because of change of base level of erosion resulting from violent downwards erosion in midstream and upstream at that time.

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