Fiche détaillée Master
| Mémoire N° | 422 |
| Auteur | BELIN-GORSIC Sandra |
| Titre | How can dendrogeomorphology associated to drone imagery contribute to GLOF hazard assessment in remote areas ? Case study in Chilean Patagonia |
| Thématique & formation | Impacts climatiques - Bachelor of arts in geography |
| Résumé | |
| Summary | With a consequent glacier mass reduction projected by the end of the century, the formation of periglacial lakes due to glaciers retreat is to be expected. Even though these changes often occur in remote areas, they can nevertheless have catastrophic impacts on populations and infrastructures through processes such as glacial lake outburst and flood. These events are results of complex geomorphological changes and subject to various timescales, thus urging the need for a multidimensional approach. The present study associates two methods in order to analyze natural hazards in a secluded national park situated in Chile. The Grosse glacier outlet was chosen after interpreting satellite imagery and historical pictures putting forward the purge of a lateral lake, which was also supported by local testimonies. Dendrogeomorphology was primarly used with an automatic detection approach to identify possible dates of occurences for glacial lake outbursts at the Grosse outlet. A total of 105 disturbed Nothofagus were sampled, highlighting 6 years as potential events as well as confirming this tree specie to be challenging but still suitable for such an analysis. The second method aimed to complete the above finding with the help of acquired aerial imagery on the field by mapping of geomorphological evidence related to GLOFs. Boulders and deposits are one of the recognized signs of a lake outburst and were thus used so as to differentiate simple floods from high magnitude events. More precisely, throughout an object-based strategy we could map deposits density and extrapolate a theoretical flow. Where the first method allowed us to select dates of potential events, the second helped us identify and map the spatial extent of evidence from a high-energy event. We could confirm that these two approaches have added value when put together in the context of complex natural hazards such as GLOFs. This master thesis identified several years/decades as possibly active from a natural hazard perspective and confirmed a significant frequency in the studied region. Such findings are believed to make a valuable contribution to historical records and help for future assessments of natural hazard in Grosse’s area. Finally, by using a two-dimensional approach this study has opened discussions about the need for various sources of information in order to capture most of the temporal and spatial dimensions of GLOFs. |
| Volée | 2018 |
| Date et heure soutenance | 10-11-2020 14:00 |
| Salle soutenance | Zoom |
| Collation | 66 pages, 38 figures, 6 tableaux |
| Remarque | |
| Mot-clés | Dendrogeomorphology, photogrammetry, hazard assessment, glacial lake outburst, object based image analysis |
| Cote bibliothèque | |
| Stage organisme | |
| Maître de stage | |
| Projet recherche | |
| Bourse | |
| Terrain d'étude ou d'application | |
| Documents associés |
fiche analytique |
| Dernière mise à jour |
2023-03-28 15:30:47 |