HAZARD AND RISK CLASSIFICATION FOR LARGE UNSTABLE ROCK SLOPES IN NORWAY — IJEGE
 
 
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HAZARD AND RISK CLASSIFICATION FOR LARGE UNSTABLE ROCK SLOPES IN NORWAY



Abstract:
We present a classification system for hazard and risk that is posed by unstable rock slopes in Norway that might undergo catastrophic failure in future and can cause loss of life. The system is scenario-based as the intensity and rate of displacement, as well as the geological structures activated by the sliding rock mass vary significantly on the slopes. In addition, for each scenario the secondary effects, such as generation of displacement waves or landslide damming of valleys with the potential of later outburst floods, are evaluated. The hazard analysis is based on two types of criteria: 1) Structural site investigations including analysis of the development of a back-scarp, lateral boundaries and basal sliding surface. This includes a kinematic analysis for sliding and toppling based on slope orientation, persistence of main structures and morphologic expressions of the sliding surface. 2) Analysis of slope activity primarily based on slide velocity, change of deformation rates, observation of rockfall activity, and historic or prehistoric events. The analysis of consequences focuses on the potential fatalities to the rock slide scenarios and secondary effects. Based on the hazard and consequence analysis each scenario is classified in a risk matrix into category low, medium or high risk.

Authors:
Reginald L. Hermanns - Geological Survey of Norway (NGU) - Trondheim, Norway
Thierry Oppikofer - Geological Survey of Norway (NGU) - Trondheim, Norway
Einar Anda - Åknes Tafjord Beredskap
Lars H. Blikra - Geological Survey of Norway (NGU) - Trondheim, Norway
Martina Böhme - Geological Survey of Norway (NGU) - Trondheim, Norway
Halvor Bunkholt - Geological Survey of Norway (NGU) - Trondheim, Norway
Giovanni B. Crosta - University of Milano-Bicocca - Milan, Italy
Halgeir Dahle - Norwegian Road Authorities
Graziella Devoli - Norwegian Road Authorities
Luzia Fischer - Geological Survey of Norway (NGU) - Trondheim, Norway
Michel Jaboyedoff - University of Lausanne - Lausanne, Switzerland
Simon Loew - ETH Zurich - Zurich, Switzerland
Stine Sætre - The county of Møre og Romsdal
Freddy Xavier Yugsi Molina - Geological Survey of Norway (NGU) - Trondheim, Norway
Keywords
catastrophic rock slope failure, secondary effects, hazard analysis, consequence analysis, risk matrix
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