東野名地すべり その２ 新旧地すべり面と応力解析

Abstract

The Higashi-nomyo landslide, located in the Niigata prefecture, has occurred repeatedly and caused many severe disasters since the 18 century. The basement rocks of this slide are mainly composed of Tertiary mudstone covered by Quaternary pyroclastics. The surface topography of the area of about 2km2, is divided into the upper part of large blocks configration disturbed by primary landslide and the lower part of gentle slope due to many secondary landslides. A greater amount of ground water in the pyroclastic masses of the primary landslide has been the source of water supply for the secondary landslides in the lower part.The historical and present slides have been the secondary landslides from the large-scale ancient primary landslide mass. The primary landslide occurred before 50ka in the Late Pleistocene and the modern type secondary landslides continued to the present have begun from 6-3ka. A present activity is extending to a part of the of the ancient primary landslide mass.