Human activity as a cause for landslides in Norway : Case study of two man-made debris flows in Otta, Central Southern Norway

Abstract

Debris flows pose serious hazards in the mountainous area of central southern Norway. On 10th June 2011, a great number of debris flows occurred in Gudbrandsdalen valley. The intense precipitation triggered most of the events; meanwhile human aspects played a vital role in the formation of two events. One is located in Solhjem and the other one is located in Sagdalen. The primary objective is about to document the two events through pictures, map study and field work. Clarifying the terrain, geological setting and slope model is very helpful for us to understand the formation process. And then, through the precipitation data study, we could not only find out the triggering threshold, but also the trend of the precipitation. Based on the slope parameters, estimation about the total flow volume and peak discharge could be done. The level of these two parameters could help us understand the level of the hazard. The main purpose of this paper is to discuss the “man-made” debris flow and its role in the formation mechanisms. And under the climate change, how the future’s brief risk estimation in the location is. Therefore, we could set up the more targeted risk mitigation measurements.