Séminaire ISTerre

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Down-slope solifluction movements and permafrost degradation in the northeastern tibetan plateau revealed by InSAR

vendredi 4 octobre 2024 - 11h00

Hugo Watine - CRPG Nancy
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The Qinghai-Tibetan Plateau (QTP) is a high periglacial landscape, and permafrost is present over most of its extent. Freeze-thaw cycles of the ground cause surface deformation and solifluction on slopes (slow downslope soil movement). Here, a methodology to automatically map slope processes using multi-temporal InSAR is developed and applied to the north-eastern QTP. The method decomposes InSAR data from multiple geometries into seasonal and cumulative components parallel and normal to the steepest slope. This approach reveals the spatial patterns of solifluction and varying dynamics across two distinct lithologies: unconsolidated sediments and consolidated rocks covered by slope debris. Observations of global irreversible subsidence and increasing amplitude of the seasonal cycles in the unconsolidated sediments document in addition an on-going permafrost degradation.

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Equipe organisatrice : Cycle sismique et déformations transitoires

Salle Dolomieu, Maison des Géosciences, 38400 Saint Martin d'Hères