Reconstructions of failure surfaces (prior to potential landslides or after their release), landslide deposits, or other palaeotopographic features are important for hazard and erosion assessment. The volumes involved in landslide and failure surfaces constrain the propagation of a landslide, and knowledge of the past topography helps us to understand these hazards. Some methods exist to characterise landslide geometry, but these methods usually require monitoring information. This study tries to assess the validity of the sloping local base level (SLBL) method for this purpose. Two sets of airborne lidar digital elevation models (DEMs) of the Kii Peninsula (Japan) are used: the first one was acquired before Typhoon Talas, and the second one was acquired after. A total of 70 deep-seated landslides occurred during this event between 2 and 5 September 2011. This study shows that the SLBL method is efficient using either the slope deformations identifiable on the DEM before the release of the landslide or a reliable 2.5-D failure surface created by using both DEMs (the 2.5-D corresponds to a surface which has only one z value for each x–y coordinate; in other words, no true vertical topography or overhang can be represented perfectly). In addition, this method allows for the reconstruction of eroded deposits and buried valleys. Most of the volumes estimated are within ±35 % of the estimation made by Chigira et al. (2013), and the coefficients of expansion range from 10 % to 25 %. These results show considerable sensitivity to the parameters used for the reconstruction of the landslide volume estimations and demonstrate the need for an efficient and fast tool to reconstruct potential landslide geometries or histories.

The extent of the melting from retreating glacier can largely influence sediment transport processes at basin scale, affecting significantly the downstream fluvial system. The analysis of spatial sediment transport pathways and of different contributions of the sub-catchment as sediment sources allows the evaluation of the melting impacts on the potential sediment connectivity, i.e. the degree of connection that controls sediment fluxes between different segments of a landscape, in basins undergoing glacier retreat.The goal of this first study is inferring the effect of the connectivity changes on a basin with a sediment dynamic influenced by glacial features. Achieving this task was possible thank to a topography-based model of sediment connectivity (IC, Connectivity Index), as developed by Cavalli et al. (2013), was applied to Navizence catchment in the Southern Swiss Alps to analyze new potential connectivity pattern due to the retreat of the main glacial edifice (Zinal glacier). To analyze sediment connectivity evolution, two Digital Terrain Models (DTMs) were used: a current DTM, obtained from high resolution photogrammetry (2 m), describing the terrain at the time of the survey (2010); a post-glacial DTM, derived from application of the Slope Local Base Level (SLBL) (Jaboyedoff & Derron, 2005) technique to the current DTM, describing the terrain after forty years of glacier retreat. As a proxy of the impedance to sediment fluxes, a weighting factor derived from tabled values of hydraulic roughness (Manning's n) was applied. In order to evaluate the potential evolution of sediment connectivity in a glacierized environment, future lateral moraines, that would be formed after glacial retreat, were mapped and inserted into the DTM based on expert knowledge.Qualitative analysis of the variation of the geomorphologic index suggested that the degree of sediment connectivity in Zinal glacier is a key factor in controlling the release of sediment between hillslopes and main channel. It also emphasizes the role of lateral moraines development in influencing the future sediment fluxes from the glacial zone, acting as barriers for the downward sediment transport.

[1] {University of Lausanne, Risk-group ISTE Institute of Earth Sciences, Lausanne, 7 Switzerland} 8 [2] {IRSTEA Grenoble, Unité de recherche Erosion Torrentielle, Neige et Avalanches, BP 9 76, 38402 Saint Martin d’Hères, France} 10 [3] {Institut de Physique du Globe de Strasbourg, CNRS UMR 7516, Ecole et Observatoire 11 des Sciences de la Terre, Université de Strasbourg, 5 rue Descartes, F-67084 Strasbourg, 12 France} 13

Regions with steep topography are potentially subject to landslide-induced tsunami, because of the proximity between lakes, rivers, sea shores and potential instabilities. The concentration of the population and infrastructures on the water body shores and downstream valleys could lead to catastrophic consequences. In order to assess comprehensively this phenomenon together with the induced risks, we have developed a tool which allows the construction of the landslide geometry, and which is able to simulate its propagation, the generation and the propagation of the wave and eventually the spread on the shores or the associated downstream flow.

The Roubine catchment located in the experimental research station of Draix-Bléone (south French Alps) is situated in Callovo-Oxfordian black marls, a lithology particularly prone to erosion and weathering processes. For 30 years, this small watershed (0.13 ha) has been monitored for analysing hillslope processes on the scale of elementary gullies. Since 2007, surface changes have been monitored by comparing high-resolution digital elevation models (HRDEMs) produced from terrestrial laser scanner (TLS). The objectives are (1) to detect and (2) to quantify the sediment production and the evolution of the gully morphology in terms of sediment availability/transport capacity vs. rainfall and runoff generation. Time series of TLS observations have been acquired periodically based on the seasonal runoff activity with a very high point cloud density ensuring a resolution of the digital elevation model (DEM) on the centimetre scale. The topographic changes over a time span of 2 years are analysed. Quantitative analyses of the seasonal erosion activity and of the sediment fluxes show and confirm that during winter, loose regolith is created by mechanical weathering, and it is eroded and accumulates in the rills and gullies. Because of limited rainfall intensity in spring, part of the material is transported in the main gullies, which are assumed to be a transport-limited erosion system. In the late spring and summer the rainfall intensities increase, allowing the regolith, weathered and accumulated in the gullies and rills during the earlier seasons, to be washed out. Later in the year the catchment acts as a sediment-limited system because no more loose regolith is available. One interesting result is the fact that in the gullies the erosion–deposition processes are more active around the slope angle value of 35°, which probably indicates a behaviour close to dry granular material. It is also observed that there exist thresholds for the rainfall events that are able to trigger significant erosion; they are above 9 mm rainfall or of an intensity of more than 1 mm min−1, values which can vary if antecedent precipitation is significant within the last 5 days.This study improves knowledge of the spatial distribution of erosion seasonality in badlands and demonstrates the potential of careful 3-D high-resolution topography using TLS to improve the understanding of erosive processes.

Abstract. The Roubine catchment located in the experimental research station of Draix-Bléone (south French Alps) is situated in Callovo-Oxfordian black marls, a lithology particularly prone to weathering processes. Since 30 years, this small watershed (0.13 ha) has been monitored for analysing hillslope erosion processes at the scale of elementary gullies. Since 2007, a monitoring of surface changes has been performed by comparing of high-resolution digital elevation models (HR-DEMs) produced from Terrestrial Laser Scanner (TLS). The objectives are (1) to detect and (2) to quantify the sediment production and the evolution of the gully morphology in terms of sediment availability/transport capacity vs. rainfall and runoff generation. Time series of TLS observations have been acquired periodically based on the seasonal runoff activity with a very high point cloud density ensuring a resolution of the DEM at the centimetre scale. The topographic changes over a time span of 4 years are analysed. Quantitative analyses of the seasonal erosion activity and of the sediment fluxes contributing to the recharge of tributary gullies and rills are presented. According to the transport capacity generated by runoff, loose regolith soil sources are eroded at different periods of the year. These are forming transient deposits in the main reach when routed downstream, evolving from a transport-limited to a supply-limited regime through the year. The monitoring allows a better understanding of the seasonal pattern of erosion processes for black marls badland-type slopes and illustrates the mode of sediment production and the temporal storage/entrainment in similar slopes. The observed surface changes caused by erosion (ablation/deposition) are quantified for the complete TLS time-series, and sediment budget maps are presented for each season. Comparisons of the TLS sediment budget map with the in situ sediment monitoring (limnigraph and sedigraph) in the stream are discussed. Intense and long duration rainfall events are the triggering factor of the major erosive events.

Climate changes can result in a wide range of variations of natural environment including retreating glaciers. Melting from glaciers will have a significant impact on the sediment transport characteristics of glacierized alpine catchments that can affect downstream channel network. Sediment connectivity assessment, i.e. the degree of connections that controls sediment fluxes between different segments of a landscape, can be useful in order to address management activity on sediment fluxes changes of alpine streams. Through the spatial characterization of the connectivity patterns of a catchment and its potential evolution it is possible to both define sediment transport pathways and estimate different contributions of the sub-catchment as sediment sources.

The inspired fraction of oxygen (FiO2) for the normobaric hypoxic condition was incorrectly reported to be 15.8 ± 0.8%. The correct FiO2 value for the NH condition is 17.9 ± 0.2% and the correct inspired pressure of oxygen (PiO2) values were 111.1 ± 1.1 vs 111.5 ± 1.0 mmHg in normobaric and hypobaric hypoxia, respectively. The authors wish to clarify and confirm that the simulated altitude was perfectly matched to the real altitude of 2250m. The error appears only in the paper. This correction has no impact on the living altitudes between the two hypoxic conditions, as PiO2 was strictly matched between conditions. As a result, there are errors in Fig 4. Please see the updated Fig 4 here. Fig 4 A. Daily values of inspired pressure of oxygen (PiO2 in mmHg) during the Live High-Train Low (LHTL) camps for the normobaric hypoxia (NH) and hypobaric hypoxia (HH) groups. B. Mean values of night oxygen pulse saturation (SpO2). Data are presented in ...

The development of susceptibility maps for debris flows is of primary importance due to population pressure in hazardous zones. However, hazard assessment by process-based modelling at a regional scale is difficult due to the complex nature of the phenomenon, the variability of local controlling factors, and the uncertainty in modelling parameters. A regional assessment must consider a simplified approach that is not highly parameter dependant and that can provide zonation with minimum data requirements. A distributed empirical model has thus been developed for regional susceptibility assessments using essentially a digital elevation model (DEM). The model is called Flow-R for Flow path assessment of gravitational hazards at a Regional scale (available free of charge under http://www.flow-r.org) and has been successfully applied to different case studies in various countries with variable data quality. It provides a substantial basis for a preliminary susceptibility assessment at a regional scale. The model was also found relevant to assess other natural hazards such as rockfall, snow avalanches and floods. The model allows for automatic source area delineation, given user criteria, and for the assessment of the propagation extent based on various spreading algorithms and simple frictional laws. We developed a new spreading algorithm, an improved version of Holmgren's direction algorithm, that is less sensitive to small variations of the DEM and that is avoiding over-channelization, and so produces more realistic extents. The choices of the datasets and the algorithms are open to the user, which makes it compliant for various applications and dataset availability. Amongst the possible datasets, the DEM is the only one that is really needed for both the source area delineation and the propagation assessment; its quality is of major importance for the results accuracy. We consider a 10 m DEM resolution as a good compromise between processing time and quality of results. However, valuable results have still been obtained on the basis of lower quality DEMs with 25 m resolution.