HR: 08:45h
AN: G11B-04    [Abstracts]
TI: Classifying and Analyzing Spatial Patterns of Surface Features in Debris Flow Fans using Curvature Parameters
AU: * Staley, D M
EM: dstaley@memphis.edu
AF: Department of Earth Sciences, University of Memphis, Johnson Hall, Memphis, TN 38152 United States
AU: * Staley, D M
EM: dstaley@memphis.edu
AF: USDA Forest Service, 740 Simms St, Golden, CO 80401 United States
AU: Volker, H
EM: hvolker@memphis.edu
AF: Department of Earth Sciences, University of Memphis, Johnson Hall, Memphis, TN 38152 United States
AU: Wasklewicz, T A
EM: twsklwcz@memphis.edu
AF: Department of Earth Sciences, University of Memphis, Johnson Hall, Memphis, TN 38152 United States
AB: A modified method of calculating profile and planform curvature is used to identify homogenous slope units (surface features, such as debris flow levees, lobes, or plugs) within alluvial fans. High-resolution DEMs were generated from Airborne Laser Swath Mapping techniques. One-meter grid nodes processed by the National Center for Airborne Laser Mapping were converted to raster datasets. ALSM data are used to assess the spatial patterns in surficial features identified in 21 debris flow fans. The debris flow fans are identified from field analysis of near vertical exposures along channels as well as surficial exposures at proximal, medial, and distal fan locations. Our observations indicate the debris flow fans are generated from clast-rich debris flow deposits. They exhibit several characteristic debris flow features that include channels, levees, interfluves, lobes, and plugs. Initial analyses indicate the length-scales appropriate for quantifying surface curvature are different for planform and profile curvature. The longitudinal profile of the fan surface contains a series of lobe-like features that have a significantly different length-scale than the channels and interfluves identified in the planimetric profile of the fans. The proper length scales are determined by minimizing the frequency of rectilinear curvature values. The statistical properties of the curvature values are then used to quantify the anisotropic variability of alluvial fan morphometry. The spatial variability is compared with the fan area, drainage basin area, fan slope and drainage basin geology to compare the variability within the debris flow fans.
DE: 1824 Geomorphology (1625)
DE: 1294 Instruments and techniques
SC: Geodesy [G]
MN: 2004 AGU Fall Meeting