Lerfall i årene 1930-1932.

Abstract

A previous paper (NGU, no. 132) by the same author treats of three recent landslips in marine clay deposits. In the present publication is given a description of some clayslides, which took place in the above mentioned years. 1. In Thamshavn near Orkanger on the Trondheimsfjord a great piece of land slid down on May 2. 1930, by which one man perished. As the greater part of the slipping masses was situated under sea a high wave rose and destroyed ships and quays in the neighbourhood. The cause of this slide is supposed to be the weight of gravel masses deposited on clayey substratum, which proved to be instable, in order to gain ground for new industrial plants on the shore. 2. The farm Bakskjul in Undrumsdal was afflicted by a landslide in December 1930, which wasted 6-7000 sq. metres of the fields. 3. At the farm Modum on the left side of Glommen river near the town Sarpsborg a mudflow forced its way into the river through a very narrow gorge as illustrated on fig. 1. The size of the area displaced was 150 by 170 metres. The landslip was probably caused by a bank burst. 4. Clayslide in Renskog, Lier. - Details are missing. 5. At Slependen near Oslo a road was cut into rocky hillside during the winter 1931.