Landscape changes and bedrock reconstruction in Gjerdrum area. Methodological approach and main results

Abstract

On 30 December 2020 a quick-clay landslide occurred in Gjerdrum, Norway. Becauseof the severe consequences, the Norwegian government appointed an externalexpert committee to investigate the landslide. In order to investigate the changes inthe landscape that could have contributed to the destabilisation of the slopes, a wideapproach was necessary. For this, the Geological Survey of Norway (NGU) hascontributed with several GIS analyses and 3D modelling.This report is a documentation of the methods utilised during the work done by NGU.The data quality of the input data for the analyses and modelling are also presented.The main results of the work are shown, but not discussed with regard to theunderlying causes and\/or triggers of the landslide. Most of the results are used anddiscussed in the report of the Gjerdrum committee.