HR: 0800h
AN: G51C-0635    [Abstracts]
TI: Monitoring Earth Surface Dynamics With Optical Imagery
AU: * Leprince, S
EM: leprincs@caltech.edu
AF: Tectonics Observatory, Geology and Planetary Science Division, California Institute of Technology, MC 100-23, 1200 E. California blvd, Pasadena, CA 91125, United States
AU: Berthier, E
EM: etienne.berthier@legos.obs-mip.fr
AF: CNRS-LEGOS, 14 av. Ed. Belin, Toulouse, 31400, France
AU: Ayoub, F
EM: fayoub@gps.caltech.edu
AF: Tectonics Observatory, Geology and Planetary Science Division, California Institute of Technology, MC 100-23, 1200 E. California blvd, Pasadena, CA 91125, United States
AU: Delacourt, C
EM: christophe.delacourt@univ-brest.fr
AF: Domaines Océaniques, UMR 6538, IUEM, Université de Bretagne Occidentale, Place Nicolas Copernic, Plouzané, 29280, France
AU: Avouac, J
EM: avouac@gps.caltech.edu
AF: Tectonics Observatory, Geology and Planetary Science Division, California Institute of Technology, MC 100-23, 1200 E. California blvd, Pasadena, CA 91125, United States
AB: Optical images can be used to measure accurately a variety of Earth surface processes such as co-seismic ground deformation, ice-flow, landsliding and sand-dunes migration. Although the technique of correlating multi- temporal images is not new, it is not widely used yet due to technical limitations - mainly geometric distortion of the images induced by the imaging system, biased correlation techniques, and implementation difficulties. Most of these obstacles were overcome by recent methodological advances implemented in a user-friendly software package, COSI-Corr, which allows for automatic and precise ortho-rectification, co-registration, and subpixel correlation of pushbroom satellite and aerial images. The procedure does not require external information such as GPS measurements of ground control points, and is solely based on the knowledge of the topography and on the ancillary data provided with the observing platform. In particular, we take advantage of the availability of accurate digital elevation models with global coverage (SRTM). Sub-pixel change detection, i.e. correlation, is then applied on the set of ortho-images produced. COSI-Corr makes it possible to measure local displacements between temporal series of images, possibly acquired by different instruments and at different resolutions, with accuracy of the measurements on the order of a small fraction of the nominal images' resolution. We apply this methodology to the measurement of the horizontal coseismic displacement field induced by the Mw 7.1 1999 Hector Mine earthquake, California, using a 10-m SPOT 4 pre-earthquake image and a 15-m ASTER post-earthquake image. We illustrate the potential of this approach to measure glacier flow, and present the horizontal displacements in the Mer de Glace area (Alps), over 26 days derived from SPOT 5 images. Landsliding is also investigated on the La Valette landslide (southern French Alps), and we present a dense measurement of the cumulative horizontal displacement over eleven months, using SPOT 5 images. Finally, we demonstrate that sand dunes migration can also be monitored. A dense and complete picture of the displacement of the sand dunes over the Great Colorado Sand Dunes national park is obtained from the correlation of two ASTER images acquired in 2000 and 2003.
UR: http://www.tectonics.caltech.edu/slip_history/spot_coseis/
DE: 0758 Remote sensing
DE: 1209 Tectonic deformation (6924)
DE: 1225 Global change from geodesy (1222, 1622, 1630, 1641, 1645, 4556)
DE: 8012 High strain deformation zones
DE: 8040 Remote sensing
SC: Geodesy [G]
MN: 2007 Fall Meeting