Gjerdrum 2020: The night of December 30, 2020, a comprehensive quick clay landslide took with it villas and apartment buildings and a 100-meter long stretch of a municipal road in Gjerdrum municipality in southeastern Norway. Ten people, including two children, were killed and just as many were injured.
Sørum, November 10, 2016: Three men who were doing forestry work were killed in a quick clay landslide in Sørum east of Oslo. The landslide was triggered by large amounts of excavated material being dumped on a slope.
Ålesund, March 26, 2008: A major rockslide caused a mountain wall to collapse over a six-story building in Ålesund, which partially collapsed. Five people were killed.
Hatlestad, September 14, 2005: Large amounts of rainfall caused a landslide in the residential area Hatlestad terrasse south of Bergen. Three people were killed and seven were injured when earth and stone masses collapsed over residential buildings on a slope.
Finneidfjord, June 1, 1996: After a powerful clay slide under water in Finneidfjord in Nordland county, several houses and 300-400 meters of E6 collapsed into the fjord. Four people were killed.
Lodalen, September 13, 1936: Parts of the nearly 1,500 meter high Ramnesfjellet collapsed into Lake Lovatnet in Sogn og Fjordane county in western Norway, causing a flood wave that swept away farms and people. 74 people were killed.
Tafjord, April 7, 1934: A part of the mountain Langhammaren collapsed into Tafjorden in Møre og Romsdal county in western Norway. The landslide triggered a flood wave that washed away houses and people. 40 people were killed.
Lodalen, January 15, 1905: Parts of Ramnefjellet collapsed, as in the accident just over 31 years later, into the lake and triggered a flood wave. 61 people were killed, most of whom were never found.
Facts: Quick clay
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Quick clays are normally relatively stable, but can become very loose if they are exposed to vibrations or increased load.
Several of the major landslides that have occurred in western Sweden are of the quick clay type.
When the clay loses its stability, it enters a fluid state and the cohesive force between the clay particles is lost. This can lead to major landslides.
Quick clay is found in Scandinavia, North America, and Russia, where it was formed in connection with the large inland ice sheets. Areas with high salt levels are most vulnerable.
Source: SGU
