On the landslide at Kinasa, Nagano

Abstract

The slope of the Mt. Iizuna fell down with a big sound on April 18, 1973. Its mud soils flowed down for 2km along two small valleys and reached to the bank of the River Susobana.
The slope of the mountain consists most of tuff-breccia. There is a sandstone or mudstone layer under the top soils on the part of the toe of slip surface.
Engineering properties of soils in the area of the landslide are investigated.
It is considered through the stability analyses that the landslide occured due to increase of pore water pressures of the ground water rised along the boundaries of the strata