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Fem testområder er målt gjentatte ganger med bakkebasert laserscanner for å avdekke terrengendringer, og for å illustrere metodens bruksområder. I prosjektet er det avdekt steinsprang, løsmasseskred og deformasjoner av større fjellparti. Rapporten belyser bakkebasert laserscanning som en mangesidig metode for skredovervåking og metodens fordeler og begrensninger kommer godt frem

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

New earth observation satellites, innovative airborne platforms and sensors, high precision laser scanners, and enhanced ground-based geophysical investigation tools are a few examples of the increasing diversity of remote sensing technologies used in landslide analysis. The use of advanced sensors and analysis methods can help to significantly increase our understanding of potentially hazardous areas and helps to reduce associated risk. However, the choice of the optimal technology, analysis method and observation strategy requires careful considerations of the landslide process in the local and regional context, and the advantages and limitations of each technique. Guidelines for the selection of the most suitable remote sensing technologies according to different landslide types, displacement velocities, observational scales and risk management strategies have been proposed. The guidelines are meant to aid operational decision making, and include information such as spatial resolution and coverage, data and processing costs, and maturity of the method. The guidelines target scientists and end-users in charge of risk management, from the detection to the monitoring and the rapid mapping of landslides. They are illustrated by recent innovative methodologies developed for the creation and updating of landslide inventory maps, for the construction of landslide deformation maps and for the quantification of hazard. The guidelines were compiled with contributions from experts on landslide remote sensing from 13 European institutions coming from 8 different countries. This work is presented within the framework of the SafeLand project funded by the European Commission’s FP7 Programme., JRC.H.7-Climate Risk Management

Au cours des 240 dernières années, 53 mouvements de versant se sont produits le long du promontoire de Québec, causant la mort de 88 personnes principalement lors de chutes de blocs. En octobre 2004, un petit éboulement a atteint la route dans une zone proche de l'éboulement de 1889 qui a tué 35 personnes et blessé 30 autres. Une image 3D a été créée par l'utilisation d'un scanner Lidar terrestre (SLT). Les sept familles de joints identifiées sont en accord avec les mesures effectuées dans de précédentes études. L'imagerie SLT a aussi permit d'estimer les volumes des instabilités passées et d'en analyser le mécanisme : un glissement rocheux qui affecte des blocs débités en parallélépipèdes par d'autres familles de joints. De plus la zone étudiée montre qu'elle est favorable aux chutes de blocs.

Terrestrial laser scanning (TLS) provides high-resolution point clouds of the topography and new TLS instruments with ranges exceeding 300 m or even 1000 m are powerful tools for characterizing and monitoring slope movements. This study focuses on the 35 million m3 Åknes rockslide in Western Norway, which is one of the most investigated and monitored rockslides in the world. The TLS point clouds are used for the structural analysis of the steep, inaccessible main scarp of the rockslide, including an assessment of the discontinuity sets and fold axes. TLS acquisitions in 2006, 2007 and 2008 provide information on 3-D displacements for the entire scanned area and are not restricted like conventional survey instruments to single measurement points. The affine transformation matrix between two TLS acquisitions precisely describes the rockslide displacements and enables their separation into translational components, such as the displacement velocity and direction, and rotational components, like toppling. This study shows the ability of TLS to obtain reliable 3-D displacement information over a large, unstable area. Finally, a possible instability model for the upper part of Åknes rockslide explains the measured translational and rotational displacements by a combination of southward planar sliding along the gneiss foliation, gravitational vertical settlement along the complex, stepped basal sliding surface and northward toppling toward the opened graben structure.

This paper proposed a method to qualify the susceptibility of large rock instabilities using observed strain and strain rates. This uses morphologic analysis and any kind of arguments to obtain activity that is ongoing: displacement velocities, deformation or rockfall activity. This method is supported by several examples

Rockfalls pose a significant threat to life and property, although significant advances in rockfall protection have been made in the past decade. Determining rockfall processes and related hazard, however, remains a difficult task, because of the complexity and intrinsic stochastic nature of the physics involved. Appropriate application of rockfall modelling tools requires a thorough understanding of their logic, assumptions, advantages, and limitations, as well as careful assessment of rockfall sources, block and slope characteristics, and model calibration data. This chapter provides a discussion of major issues in rockfall definition, characterisation, and modelling, with special emphasis on rockfall runout. Our discussion is supported by modelling examples carried out using the 3D simulator Hy-STONE. Different modelling approaches are critically evaluated, including the empirical shadow angle method, and 2D and 3D mathematical models. Application of the shadow angle concept requires the user to be aware of several issues related to definition of the shadow angle and the effects of morphological constraints. Most limitations of empirical approaches can be overcome with mathematical models that account for slope morphology and roughness, energy dissipation at impact or by rolling, and the effects of vegetation, block fragmentation, and block-structure interaction. We discuss different modelling approaches and calibration problems and the important dependency of model parameters and results on correct characterisation of topography.

Giant, deep-seated gravitational slope deformations (DSGSD) affecting entire high-relief valley walls are common in alpine areas, and influence the evolution of mountain landscapes and the related hazards. In the last few years, new characterisation approaches and emerging technology shed new light on the occurrence, distribution, activity, and mechanisms of these spectacular slope failures. This chapter is aimed at providing an overview of alpine DSGSD, as well as a discussion of outstanding issues and future research needs. We review the definition of DSGSD and its typical features, field evidence, settings, and mechanisms. We discuss the distribution and controls on DSGSD occurrence based on the analysis of the first-ever orogen-scale inventory of these phenomena, including over 900 individual phenomena in the European Alps. We demonstrate that DSGSDs are widespread in active orogenic settings and chiefly occur in formerly glaciated areas under significant structural controls, and show that alpine DSGSDs are often active phenomena with a engineering significance. We use the emblematic case study of the Cima di Mandriole sackung to illustrate the complex relations among rock structure, the morpho-climatic evolution of Alpine valleys, and man-made structures, and point out future research needs.