Close-Range Sensing of Alpine Glaciers

Glacial processes can have a strong impact on human activities in terms of hazards and freshwater supply. Therefore, scientific observation is fundamental to understand their current state and possible evolution. To achieve this aim, various monitoring systems have been developed in the last decades to monitor different geophysical and geochemical properties. In this manuscript, we describe examples of close-range monitoring sensors to measure the glacier dynamics: (i) terrestrial interferometric radar, (ii) monoscopic time-lapse camera, (iii) total station, (iv) laser scanner, (v) ground-penetrating radar and (vi) structure form motion. We present the monitoring applications in the Planpincieux and Grandes Jorasses glaciers, which are located in the touristic area of the Italian side of the Mont Blanc massif. In recent years, the Planpincieux-Grandes Jorasses complex has become an open-air research laboratory of glacial monitoring techniques. Many close-range surveys have been conducted in this environment and a permanent network of monitoring systems that measures glacier surface deformation is presently active

The use of unmanned aerial vehicles (UAVs) for engineering geology applications

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Multisource data of glacier kinematics

surface kinematics data of the Planpincieux and Grandes Jorasses glaciers (Mont Blanc area), collected by robotised total station, time-lapse camera and terrestrial interferometric rada

Evidences of Bedrock Forcing on Glacier Morphodynamics: A Case Study in Italian Alps

In mountain glaciers, the influence of bedrock geometry on glacier surface morphology is often assumed; quantitative evidence, however, is rare. In our research, we measured the ice thickness of the Planpincieux Glacier (North-west Italy) and detected the bedrock topography using ground-penetrating radar. Additionally, we investigated the glacier surface morphology using structure from motion and the glacier kinematics using digital image correlation of terrestrial images. A digital terrain analysis showed evidence of recurrent crevasses whose position corresponded to bedrock steps. On average, since 2014, their positions varied between 6 and 14 m and were 40 ± 8 m downstream of the bedrock steps. Bedrock and glacier topography presented out-of-phase correlated undulations that approximately fit a sinusoidal function of different amplitude. Moreover, we show the morphological evolution of an unstable sector whose thickness at the end of the ablation seasons has remained approximately constant since 2014. Contrarily, the ice melting during the 2020 ablation season caused a volume loss of >30%. Since, in general, the damages provoked by a potential ice avalanche depend primarily on the involved volume, this finding demonstrates that frequent morphology monitoring is essential for correct glacial hazard assessment.ISSN:2296-646

Mutazione della proteina SP-C: una causa insolita di sindrome da distress respiratorio

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Assessing the rock failure return period on an unstable Alpine rock wall based on volume-frequency relationships: The Brenva Spur (3916 m a.s.l., Aosta Valley, Italy)

International audienceDefining the relationship between volume and return period is critical when estimating the risk of rockfalls and/ or rock avalanche, especially during continued global warming at high altitudes that threatens rock wall stability. Characterizing the volume-frequency relationship based on historical datasets is, however, limited by observation and quantification biases, which have not received enough attention. Here, to monitor recent activities for the Brenva Spur (Mont-Blanc massif, Italy) that is also a rock avalanche scar and estimate the return period of future rock failures based on the volume-frequency relationship (and the corresponding uncertainty), a structure-from-motion photogrammetric survey was conducted from 2017 to 2021. 39 rockfall sources with volumes ranging from 11 to 13,250 m 3 were identified within the scar. The total failure volume is 22,438 m 3 , with an associated erosion rate of 15.5 mm/year, indicating very active morphodynamics possibly linked to the permafrost evolution in the spur. The volumes were characterized by a negative power-law that fits significant two events in 2016 (3.4 × 10 4 m 3) and one in 1997 (2.0 × 10 6 m 3) remarkably well, and the randomness of the fit was evaluated by a Monte Carlo approach. 7 potential failure scenarios ranging from 3.1 × 10 4 m 3 (S 1) to 4.8 × 10 6 m 3 (S 7) were defined according to a structural analysis and the sloping local base level concept. Their extrapolated return periods derived by the power-law fit indicate a longer return period for the maximum failure scenario than for the smaller scenarios. S 1 has a 50% chance of occurring every 3 years, while S 7 has a 50% chance of occurring every 31 years. Though the median return period of S 7 is 31 years, the 95% and 68.2% confidence intervals range from 8 to 399 years and 14 to 93 years, respectively, which reflects a high level of uncertainty but is realistic when considering global warming, progressive rock failure, etc. In addition to characterizing recent rock failure activities in high mountains, this study offers a preliminary examination of the return periods of some extreme scenarios and provides primary data for risk management in mountainous areas that are very sensitive to global warming

Analysis of potentially hazardous rockglaciers in Aosta Valley (Italy): the Pointe d'Arpisson destabilized rockglacier

International audienc

Emorragia polmonare....... e non solo.......

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Cardiopatia congenita complessa e disturbi del ritmo

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