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Paper No. 384-5
Presentation Time: 9:00 AM-6:30 PM
PRELIMINARY SURFICIAL MAPPING OF THE DENALI NATIONAL PARK AND PRESERVE ROAD CORRIDOR: IMPLICATIONS FOR LANDSLIDE HAZARDS IN A CHANGING CLIMATE
Landslides in Denali National Park and Preserve pose persistent hazards to people and infrastructure. Warming climate and permafrost degradation is likely to increase landslide hazards in this and other high-latitude regions. Increased landslide frequency and magnitude will exacerbate existing challenges to maintaining the Park Road, the sole access to the interior of the park. To better understand the factors that control landslide occurrence in the study region, we are mapping surficial geology of the Park Road corridor. We will delineate all landslides within the map area and characterize the geomorphic conditions at failure sites, including type of failure, underlying lithology, slope parameters, and active layer thickness. Here we present a preliminary map of surficial geology for two reaches along the Park Road at 1:10,000 scale. Bedrock geology is dominated by extrusive lithologies of the Teklanika Volcanics formation; basalt and greenstone of the Nikolai Greenstone formation; sandstone and conglomerate of the Cantwell formation; and unconsolidated Tertiary and Quaternary sedimentary units. Based on initial field work, landslides in these areas appear to occur in altered felsic volcanic rocks where clay layers facilitate sliding, and in unconsolidated units in areas of high relief and/or where the Park Road cuts toe slopes. Additionally, we surveyed two small, active layer detachments on shallow slopes using a terrestrial laser scanner to track downslope movement over time. Future work will evaluate the relationships between landsliding and climate change as expressed via permafrost degradation. To do so, we will evaluate the relationship between depth of the active layer and landslide frequency, quantify the mass of carbon mobilized by small landslides, and conduct a field-based validation of an existing model of permafrost extent within the park.