The picture above is from the quick clay slide in Kattmarka near Namsos in mid Norway, 13th March 2009. The whole area, about 250 m wide, with houses and dwellings slid out and were moved about 100 m to the sea. The slide was caused by blasting in connection with road work, seen in the far right of the picture. Luckily no persons were killed in this incident.
When infrastructure and buildings are hit by a landslide, the results can be catastrophic. Climate change will lead to more soil slides in areas which have not previously experienced such events.
Since its establishment in 1953, NGI has worked on the assessment of rock and soil slides. A central focus is the understanding of the mechanisms which cause slides. The core expertise is a knowledge of the strength and deformation properties of soil and the changes in these properties due to precipitation, changes in water content and loading.
Quick clay slide in in Trøgstad, Norway, 1967
In connection with the risk mapping of quick clay areas in Norway, NGI devised a method for quantifying the degree of hazard (probability) and consequences of quick clay slides. The risk is the combination of the degree of hazard and the consequences.
NGI's specialist expertise
- material behaviour and trigger mechanisms
- assessment of run-out distance and slide risk
- engineering design of protection measures and mitigation and risk reduction methods.
NGI is involved in several international projects for mapping and reducing the risk of landslides, and for knowledge transfer to local authorities. An example is South and Central America, where densely populated areas have repeatedly been hit by landslide incidents due to extreme precipitation and earthquakes.
Research and development
The research effort at NGI in the field of soil slides is concentrated on the following topics:
- mapping, identification and quantification of the degree of hazard of exposed areas
- the influence of climate change on soil slides
- development of methods for securing and monitoring and issuing warnings of landslide hazards
- analysis of run-out distance of debris flows
In the period 2002-2012, NGI led the International Centre for Geohazards (ICG), a Norwegian "Centre of Excellence" (SFF). ICG carried out research on the assessment, prevention and mitigation of geohazards, including risk of landslide in soil and rock due to rainfall, flooding, earthquakes and human intervention, and the geological risks in deep waters. The Centre also contributed to the education of researchers and specialists in these fields. NGI's partners in ICG were the University of Oslo (UiO), the Norwegian University of Science and Technology in Trondheim (NTNU), the Geological Survey of Norway (NGU), and NORSAR.