Séminaire ISTerre

Remote sensing and wireless techniques to identify and monitor slope instabilities in the Himalaya

lundi 28 septembre 2020 - 11h00
Benedetta Dini  - Schoool of Environmental Sciences, University of East Anglia, Norwich, UK
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The presentation is structured in two parts, each targeting different studies and different aspects of hazardous landslide detection and monitoring with different techniques in two different Himalayan countries. The first part focuses on a large-scale study in the Himalaya of Bhutan by means of remote sensing techniques (optical images and Synthetic Aperture Radar Differential Interferometry - DInSAR). This study revealed the presence of large, slow moving rock slope instabilities that, in some cases, threaten a growing, yet fragile infrastructure. The analysis, based on the generation and inspection of more than 500 individual interferograms and of time series from different sensors, allowed the generation of a likelihood of activity map of previously unknown instabilities and the identification of areas of reversible displacements associated with permafrost or ground water table variations. An interesting case was also brought to light by this analysis, in which a hydropower dam and a deep-seated landslide interact dangerously, reinforcing the idea that DInSAR should be considered as a powerful technique to be routinely implemented to evaluate the suitability of a site for large engineering projects. The second part of the presentation covers a pilot study concerning the potential of the Internet of Things in the context of landslide early warning systems. Recently, a network of LoRa wireless sensors, equipped with GPS and accelerometer, was installed in the upper Bhote Koshi catchment in northeastern Nepal. The aim of the network is to capture in real time hazardous boulder movements that during the monsoon may amplify landslide and flood hazard in a disaster-prone area. This novel approach has produced promising results in capturing the movement of the tagged boulders in real-time and has the potential in the future to be integrated in cost-effective monitoring and early warning systems.

Equipe organisatrice : Géophysique des Risques et de l’Environnement

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères