HR: 0830h
AN: H51D-1096    [PDF]
TI: Investigating Effects of Resolution on Landslide Identification and Landscape Attributes in the Queen Charlotte Islands, B.C.
AU: Sjogren, D
EM: sjogren@ucalgary.ca
AF: Earth Sciences Program, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4 Canada
AU: * Martin, Y
EM: ymartin@ucalgary.ca
AF: Department of Geography, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4 Canada
AB: Two exceptional mass wasting inventories (Rood, 1984; Gimbarzevsky, 1988) have been collected and analyzed for the Queen Charlotte Islands, British Columbia. These islands are located about 80 km off the coast of British Columbia, have a mild, wet climate and are seismically active. These factors contribute to a high frequency of landsliding. The Gimbarzevsky database consists of about 8000 debris slides, debris avalanches and debris flows over the entire 10,000 km$^{2}$ of the Queen Charlotte Islands. Events were identified from 1:50,000 panchromatic aerial photographs. Large grid cells (1 km$^{2}$) were used to classify landslide attributes, such as gradient and aspect. The Rood database consists of about a thousand events covering a total area of 350 km$^{2}$ in both logged and unlogged terrain. Failures were identified from 1:11,000 and 1:13,000 aerial photographs. Terrain attributes, such as initiation gradient, were obtained using photogrammetric techniques. The present study explores the effects of topographic data (DEM) resolution and air photo resolution on landsliding analysis. For the former, landscape attributes associated with mass movements, such as initiation gradient and aspect, are compared for the original Gimbarzevsky results (based on 1-km grid cells) and new results for this database derived from 100-m DEM data. For the latter, we explore the effects of aerial photograph scale on landslide identification for the Rood and Gimbarzevsky databases. In addition, we explore the benefits in deriving initiation gradients from detailed, yet time-consuming, photogrammetric techniques versus more automated approaches using existing DEM data. References: Gimbarzevsky, P. (1988) Mass Wasting on the Queen Charlotte Islands: A Regional Inventory, B.C. Ministry of Forests, Land Management Report 29; Rood, K. (1984) An Aerial Photograph Inventory of the Frequency and Yield of Mass Wasting on the Queen Charlotte Islands, B.C., B.C. Ministry of Forests, Land Management Report 34
DE: 1815 Erosion and sedimentation
DE: 1824 Geomorphology (1625)
SC: Hydrology [H]
MN: 2003 Fall Meeting