On the Koshiozawa Landslide, Oshika Village, Nagano Prefecture, Central Japan
1981 Volume 17 Issue 4 Pages 1-9_1
Details
1981 Volume 17 Issue 4 Pages 1-9_1
By the field survey up to date we could find some characteristics of the landslide here and a countermeasure against it as follows:
(1) an incomplete landslide occurred here on a developed fractural zone of crystalline schist on Sanbagawa belt. We may consider it a cataclastic landslide.
(2) it occurred on one of block-areas divided by several faults and we can estimate several older landslides in this place.
(3) It formed a scarp, due to jutting of bed fractures swollen by invaded ground water.
(4) escarpment occurred on a penetrating band of serpentine. We found 2 weak bands like this around here.
(5) in Koshio valley check dams and simple dams lifted river beds, and infiltrated ground water into the fracture zone.
(6) as an effective countermeasure we suggest here draining work of ground water at the upper position of stream confronte with the landslide.
