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International audience; The impact of falling rocks on human activities can be hindered using protection measures such as rockfall barriers, embankments and other passive structures but also through the presence of forests. In order to study the effect of a forest on rockfall trajectory, a site neighboring a village in Central Greece was selected which has a well-recorded rockfall history in the last 50 years. The village is limited by a relatively dense forest, which lies on a limestone scree slope. An assessment of the role played by the forest stands on the site was done using the Energy Line Angle concept and conclusions on the residual rockfall risk on houses are drawn.

International audience; In this communication, the influence of the impact location and boulder shape is studied to assess the efficiency of net fences (under such impacts). This work should contribute to understand the behavior of net fences in real conditions (boulder size, energy level, crossing height).

International audience; Ambient vibration techniques are increasingly used for monitoring landslides. Two types of rapid landslides are considered in this study: mudslides in clayey sediments and rockfalls of intermediate size (10(3)-10(5) m(3)) in rigid rocks. The change of ambient vibration properties with time allows variations of internal mass characteristics to be obtained. This information is complementary to the surface motion measurements derived from air or ground based techniques and could be included in a monitoring system for landslides exhibiting a rapid mass movement.

© Springer International Publishing Switzerland 2015. The devastating 2008 Wenchuan earthquake with a magnitude of Mw 7.9 was the largest seismic event in China in more than 50 years. It triggered numerous landslides over a broad area, some of which dammed rivers, posing severe threats to downstream settlements. The coseismic landslides are classified into rock/debris avalanches, debris flows, rock/debris slides and rock falls. A number of representative examples of each type and the corresponding landslide dam features were studied. According to dam composition material and sedimen-tological features, landslide dams were categorized into three types: dams mainly composed of large boulders and blocks; dams composed of unconsolidated fine debris; and dams with partly intact rock strata at the base topped by large boulders and blocks or soil with rock fragments, showing two-layered or three-layered depositional structure. This classification is linked to the typology of damming landslides and considered to be a preliminary indicator of dam stability. In addition, dam stability also largely depends on valley morphometry as well as landslide runout distance and mechanism. .

This paper reports preliminary results of a feasibility project developed in cooperation with National Agency for Cultural Heritage Preservation of Georgia, and aimed at envisaging the stability conditions of the Vardzia monastery slope (rupestrian city cave in the south-western Georgia). The aim is the implementation of a low-impact monitoring system together with long-term mitigation/conservation policies. A field analysis was conducted to reconstruct geometry of the rocky cliff, characteristics of discontinuities, main failure modes, and volume of potential unstable blocks and geomechanical parameters. Instability processes are the combination of causative factors such as the following: lithology, frequency and orientation of discontinuities, slope orientation, physical and mechanical characteristics of slope-forming materials, and morphological and hydrological boundary conditions. The combined adoption of different survey techniques (e.g., 3D laser scanner, ground-based radar interferometry) could be the best solution in the interdisciplinary field of cultural heritage preservation policies. The collected data will be the basis for future activities to be completed in collaboration with local authorities for a complete hazard and risk characterization for the monastery site and the development of an early warning system to allow safe exploitation for touristic activities and for historical site preservation.

Rockfalls pose a significant threat to life and property, thus rockfall protection is a major issue in areas exposed to severe rockfall hazard. Rockfall protection approaches include quantitative rockfall hazard and risk assessment, as well as the design of structural countermeasures. These require a sound and robust quantification of 3D rockfall trajectories, distribution and intensity of impacts, and magnitude and variability of involved dynamic quantities. Providing highly reliable modeling inputs to rockfall protection remains a difficult task, because of the complexity and intrinsic stochastic nature of rockfall physics and the uncertainty of all the relevant parameters. However, significant advances in rockfall analysis have been made in the last decade, and modern 3D rockfall modeling techniques now provide effective tools to support rockfall protection activities, even in difficult design conditions. Nevertheless, their use can still be complex and raises a series of difficult steps both in the modeling and the analysis of the results. In this paper, we provide an overview of rockfall analysis aspects relevant to rockfall protection, as well as examples of applications of modern 3D rockfall runout modeling techniques in rockfall hazard and risk assessment, and countermeasure selection, design and optimization. .

Rock fall hazard assessment and zoning are very important for an appropriate land use planning in mountainous areas. However, they are complex topics, and current methodologies adopted for producing zoning maps do not provide satisfactory results, due to assumptions and uncertainties involved in hazard assessment. This paper presents an application of the Cadanav methodology, which attempts at reducing hypotheses and related uncertainties particularly affecting the use of rock fall modelling results and the techniques for combining energy and frequency. This procedure allows for a quantitative evaluation of rock fall hazards based on the combination of relevant parameters also determined in quantitative terms. The hazard is obtained at any point of the slope by means of a new tool defined as "hazard curve". Aimed to hazard degree assessment and zoning at the local scale, the Cadanav methodology is presented with reference to a case study set in the Canton of Valais (Switzerland). Different scenarios in terms of rock fall frequency are considered, to illustrate how this procedure can also describe the way hazard evolves along the slope, if a change in the probability of failure occurs.

The Feifeng Mountain tourist resort is famous for the ancient caves and drifting activities along the Yongan River. Because of steep slope, lithology (tuff overlying a thick soft layer), tectonic structure, and the underground excavation in ancient times, the area is seriously affected by rockfalls. A quantitative rockfall individual risk assessment has been performed, by using either a 2D and a 3D modelling approach. The 2D approach results in an overestimation of risk along the a priori defined paths, due to the impossibility to consider lateral spread of rockfall trajectories. The 3D approach allows for simulating the lateral dispersion and the trajectories along convergent topography, locally increasing the Individual Risk level.