Submitted to: Earth Surface Processes and Landforms
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/18/2006
Publication Date: 4/30/2007
Citation: Wells, R.R., Prasad, S.N., Romkens, M.J. 2007. Soil deformation and its spectral signature. Earth Surface Processes and Landforms. 32(5):786-793. Interpretive Summary: Investigations were conducted to reveal hidden surface patterns in a cracking clay soil. The work was conducted in the laboratory with an automated infrared laser surveying system. Measurements of the soil surface were collected and analyzed to determine whether cracking patterns were detectable prior to the onset of cracking. In other words, does the wetting pattern affect the cracking patterns. Spectral analysis was used to detect the patterns in the surface. The periodicity of the surface relief was 8 to 12 cm, which followed observed measurements of cracking. This suggests that the eventual crack pattern is determine during the wetting phase rather than through desiccation.
Technical Abstract: Spatial variation of the surface micro-relief in a Sharkey clay soil was investigated. The micro-relief measurements of the soil surface were obtained using an automated infrared laser system and evaluated with methods of Fourier analysis. The authors illustrate the spectral technique with a simple example and then use the technique to interpret the surface micro-relief patterns of soil samples subjected to a range of simulated rainstorm intensities. The periodicity of the soil surface micro-relief in the longitudinal direction was 8 to 12 cm. The periodic surface micro-relief patterns immediately following the rainstorm are shown to be an early manifestation of the cracking pattern.