HR: 1340h
AN: H23A-1103    [Abstracts]
TI: Ground Penetrating Radar Response to thin layers: Example from Waites Island, South Carolina
AU: Guha, S
EM: sguha@mail.usf.edu
AF: University of South Florida, 4204 E Fowler Avenue, SCA 528, Tampa, Fl 33620
AU: Kruse, S E
EM: skruse@chuma1.cas.usf.edu
AF: University of South Florida, 4204 E Fowler Avenue, SCA 528, Tampa, Fl 33620
AU: * Wright, E
EM: ewright@coastal.edu
AF: Coastal Carolina University, PO BOX 261954, Conway, SC 29528
AB: Ground penetrating radar is commonly utilized in stratigraphic interpretation of depositional environments. In many settings, the thickness of layers (mm scale) is much smaller than radar wavelengths (tens of cms). The presence of thin layers in the shallow subsurface can pose difficulty for identification of reflecting surfaces in the radar profiles. A sequence of such layers will result in reflection patterns that are the result of complex interference of the reflecting radar energy. No single reflection event can be assigned to each reflecting contact. In order to better understand radar wave behavior in response to thin layer patterns characteristic of sedimentary environments, we have developed numerical models to simulate GPR reflections at frequencies between 50MHz and 500MHz. Several suites of FDTD (finite-difference-time-domain) models have been run with different possible layer patterns, simulating thin layers ranging in thickness from 1 mm to ~­š 1/4 or 1/3 of the radar wavelength. Models are also compared against GPR surveys carried out at Waites Island, South Carolina. Sediment cores from this barrier island contain some good examples of thin layers in the form of beach laminations. On Waites Island, the presence of magnetite as a constituent heavy mineral in the mm-thick laminations clearly plays a significant role in causing radar reflections.
DE: 5109 Magnetic and electrical properties
DE: 1829 Groundwater hydrology
DE: 1894 Instruments and techniques
DE: 0694 Instrumentation and techniques
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting