高知県繁藤地区の大規模崩壊について (その1)-崩壊地の地盤構造の特徴-

Abstract

On July 5th, 1972, a large scale landslide occurred on the slope at the Shigeto section inKochi Prefecture Shikoku, District. It caused a considerable desaster with loss of 50 humanlives, destruction of 11 houses, damage of the National Rord No. 32 and the National Railwayover a length of 150m.On the landslide area and environs, following investigations of the geological conditionsof the ground structure were carried out:(1) The seismic prospecting(2) the electrical resistivity prospecting(3) the naturaral radioactivity survey(4) the electrical conductivity survey of spring water(5) the infiltration testAccording to the investigations and additional data of the boring, the geological conditionof the landslide area involving fault and fractured rock zone is elucidate. As a cause ofoccurrence of landslide, the special under ground structure of this area which concentratedthe groundwater can be pointed out.