YUKON EXPLORATION AND GEOLOGY 2003 107 Permafrost and landslide activity:

• Main Authors: Crystal A. Huscroft, Panya S. Lipovsky, Jeffrey D. Bond
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Yukon; Le Fond; Takhini; Silver Creek; Takhini River; Haeckel Hill; Marshall Creek; Mount Sumanik; Ice; permafrost; pergélisol
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.556.3289; http://publications.gc.ca/collections/Collection/R71-41-2003E(9).pdf

Five case studies of recent landslides in southwestern Yukon Territory illustrate the role of permafrost in landslide processes of the region. In the Marshall Creek basin, permafrost degradation after recent forest fires caused numerous debris flows near the valley bottom. Similarly, on Haeckel Hill, fire-related deepening of the active layer has facilitated active layer detachment slides on upper hillside slopes. In the Kluane Range, the interface between frozen and unfrozen ground appears to control the depth of movement for active layer detachment slides and debris flows along Silver Creek. The failure mechanism on Mount Sumanik is controlled by a frozen substrate, which contributes to a reduction in drainage and elevated pore-water pressure. Lastly, thawing of segregated ice has caused a thaw slump of fine-grained sediment in lacustrine terraces along Takhini River. RÉSUMÉ Cinq études de glissements de terrain récents illustrent le rôle du pergélisol dans les processus de glissement dans la région. Dans le bassin du ruisseau Marshall, la dégradation du pergélisol après des feux de forêt récents a provoqué de nombreuses coulées de débris dans le fond de la vallée. Dans une situation analogue, sur la colline Haeckel, le creusement du mollisol causé par le feu a fait