Contribution to the Researches of Land Conservation in Mogami District, Yamagata Prefecture

Abstract

Landslides prevail in the western mountainous part which consists mainly of the oil-field Tertiary sediments (mudstone), whereas naked peaks and bare slopes which have succeeded to a wide-spread debris-fall owing to snow avalanches, occur in the eastern loftier ridge which a harder volcanic complex, so-called green tuff, has constructed. Stabilizing condition in the meaning of land conservation is kept in the central basin, where younger deposits intercalated by lignite form a lower, hilly land.The authors have visited over a number of disastrous sites in this district, having tried both geomorphological and geological inspection. They also have made several experiments on the materials taken from the sites, such as permeability measurement in situ, clay minerals detection by means of chemical method, consistency test and so on with an effective success.