Leirfall ved Holund i Grong 1942.

Abstract

On january 19th, 1942 a violent clay-slide took place near the farm Holund in Grong district, east of Namsos. The size of the displaced area was about 1 acre. A heavy wave of liquid clay rushed down into a small valley. It washed up the slope to level 25 m high, was then reflected, this being repeated 3 or 4 times. In September the same year a new slide took place in connection with the first one. The slide by Holund took place in a typical \"kvikkleir\" deposit. In May 1943 the author took a visit to Holund. Undisturbed samples were taken after the Swedish method (1). A calculation was made on the stability of another clayey hillslide, and a sketch map was made over the area. The clay-slide by Holund was due to the natural meta-stability of the \"kvikkleir\" deposit. Good descriptions of this type of slay-slides is given by Gunnar Holmsen.