HR: 14:40h
AN: H13G-05    [Abstracts]
TI: Towards the Quantitative Characterization of Fractures Using GPR
AU: * Tsoflias, G P
EM: tsoflias@ku.edu
AF: The University of Kansas, 1475 Jayhawk Blvd. 120 Lindley Hall, Lawrence, KS 66045-7613 United States
AU: Hoch, A
EM: hocha@ku.edu
AF: The University of Kansas, 1475 Jayhawk Blvd. 120 Lindley Hall, Lawrence, KS 66045-7613 United States
AB: GPR methods have been used successfully in hydrogeophysical studies for the detection of fractures. However, GPR studies have provided very limited quantitative information about the physical parameters that control fracture hydraulic properties, such as fracture aperture and aperture variation, channeling along the fracture plane, fracture surface roughness, and fluid content of fractures. In this study we examine the polarization properties of electromagnetic wavefields and develop analytical forward models of the GPR response of discrete fractures in geologic environments. We consider different geologic environments containing fractures of varying aperture, orientation, and fluid content. We simulate analytically the response of these fractures to transmitting and reflecting electromagnetic waves of varying polarization and frequency. We find that for a range of signal frequencies and angles of incidence, varying polarization GPR signals display characteristic amplitude and phase responses that allow for the determination of fracture fluid content and fracture aperture. Our findings indicate that quantitative characterization of fracture hydraulic properties can be achieved by considering the amplitude and phase response of varying polarization GPR wavefields.
DE: 5100 PHYSICAL PROPERTIES OF ROCKS
DE: 1832 Groundwater transport
DE: 1894 Instruments and techniques
DE: 0400 Biogeosciences
DE: 0900 EXPLORATION GEOPHYSICS
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting