HR: 1340h
AN: G13B-0808    [Abstracts]
TI: An Alluvial Fan Spectral Surface Analysis Comparison of Airborne LIDAR and GPS Data for the Calico Fault, Mojave Desert, California
AU: * Blumentritt, D J
EM: blum0123@umn.edu
AF: National Center for Earth-surface Dynamics, Dept. of Geology and Geophysics, University of Minnesota, 310 Pillsbury Drive SE, Minneapolis, MN 55455 United States
AU: Oskin, M E
EM: oskin@email.unc.edu
AF: University of North Carolina at Chapel Hill, CB #3315, Chapel Hill, NC 27599 United States
AU: Perg, L A
EM: lperg@umn.edu
AF: National Center for Earth-surface Dynamics, Dept. of Geology and Geophysics, University of Minnesota, 310 Pillsbury Drive SE, Minneapolis, MN 55455 United States
AB: Airborne LIDAR imaging is an effective tool to acquire large areas of high-resolution topography for surface analysis. Surface roughness characteristics can be matched throughout the LIDAR coverage area in order to determine relative surface chronologies, which will aid in the estimation of fault slip rates. It is then possible to "spot check" surfaces with absolute dating methods. Un-vegetated desert alluvial fan surfaces of differing ages and roughness in the Mojave Desert, California, provide an attractive natural setting to test how well surface characteristics are represented by LIDAR data in comparison to ground survey points. LIDAR data were acquired over a chronosequence of geomorphic surfaces at the foot of the northern Rodman Mountains as part of a companion study of the slip rate of the Calico fault. On the ground, high-resolution differential GPS data were measured from four separate fan surfaces of different ages and smoothness characteristics. GPS survey points were acquired at 25 cm spacing on orthogonal transects spaced 50 m apart. Spectral analysis of surface elevations provides a tool for comparing the topography signal between LIDAR and survey data. The LIDAR data has an approximate resolution of 1 meter, which is good for detecting landforms, such as bar and swale, on a spectral order of tens of meters. However, the raw LIDAR data points are not the same distance apart in geographic space, so when spectral analysis is applied to the LIDAR data it must be resampled. Alternatively, raw LIDAR data series may be treated as a time series, however this restricts analysis to the swath orientation.
DE: 1824 Geomorphology (1625)
DE: 1894 Instruments and techniques
DE: 1204 Control surveys
SC: Geodesy [G]
MN: 2004 AGU Fall Meeting