Laboratory Experiments and Numerical Modelling of Tsunamis Generated by Rock Slides into Fjords, 2015

The primary objective of this project was to establish procedures and facilitate operational models for assessment and analysis of possible future rock slide tsunamis. Increased understanding and improved computational tools for tsunamis generated by rock slides were sought through a combination of laboratory studies and numerical modeling. Coupling of various mathematical models for rock slide generation, propagation, and run-up of waves were emphasized. One of the possible tsunamigenic rock slopes in Norway today is located at Åknes along Storfjorden, western Norway. As a result of the need for risk assessment and management in the area, the Åknes/Tafjord project was initiated in 2004 (from 2009: Åknes/Tafjord Beredskap IKS) as a comprehensive R&D, monitoring, and early warning project related to large unstable rock slopes and their consequences in terms of tsunamis threatening local communities. The maximum volume of the potential Åknes rock slide is estimated to 54 million m3, and movements of up to 20 cm/year are recorded more than 900 m.a.s.l. The present findings of the Åknes/Tafjord project and the existing and unique 1:500 scale fjord model facilities form an excellent starting point for additional basic research required to establis h procedures and operational models. The deliverables will be a significant contribution to reduce hazard and risk related to rock slide tsunamis in fjords, lakes, and hydropower reservoirs. The project is a close cooperation between the Department of Mathematics at University of Oslo (UiO), the Norwegian Geotechnical Institute (NGI), and SINTEF Coast and Harbour Laboratory (CHL). Cornell University (the modeling part) and Georgia Institute of Technology (the experimental part) were also collaborators in the project.