HR: 0830h
AN: NS41B-03    [Abstracts]
TI: Shear Seismic Anisotropy Within a Relay Ramp Structure, Baton Rouge Fault System, Louisiana
AU: * Westbrook, C C
EM: cwestbrook@geol.lsu.edu
AF: Department of Geology and Geophysics, Louisiana State University, E235 Howe-Russell, Baton Rouge, LA 70803 United States
AU: Lorenzo, J M
EM: jlorenzo@geol.lsu.edu
AF: Department of Geology and Geophysics, Louisiana State University, E235 Howe-Russell, Baton Rouge, LA 70803 United States
AU: Saanumi, A
EM: adeniyi@geol.lsu.edu
AF: Department of Geology and Geophysics, Louisiana State University, E235 Howe-Russell, Baton Rouge, LA 70803 United States
AU: Zapata, R
EM: rzapata@geol.lsu.edu
AF: Department of Geology and Geophysics, Louisiana State University, E235 Howe-Russell, Baton Rouge, LA 70803 United States
AU: Egnew, S
EM: segnew@geol.lsu.edu
AF: Department of Geology and Geophysics, Louisiana State University, E235 Howe-Russell, Baton Rouge, LA 70803 United States
AB: Shear wave data were acquired to characterize the fracture pattern at depth within a relay ramp structure associated with a Pleistocene Growth Fault system in Louisiana. By using both the degree and maximum direction of shear seismic anisotropy, we estimate the extent and orientation preference of subsurface fractures. Multi-source shear seismic data were generated by striking an I-beam, cut to 18 inches in length, from either side. Data collected in two control surveys show an expected 10-15% seismic anisotropy between fast and slow polarization directions, with the maximum anisotropy produced with the survey coordinate system being rotated parallel to the fault scarp. Data collected within the relay ramp structure indicate the principle direction(s) of stress, with depth, as well as density of fracturing. The results of this experiment should aid in regional fluid flow modeling and in local infrastructure planning such as residential construction, groundwater usage evaluation, and waste disposal site selection. This experiment has defined a successful technique that should be used when conducting similar studies in the region.
DE: 5102 Acoustic properties
DE: 5199 General or miscellaneous
SC: Near-Surface Geophysics [NS]
MN: 2005 Joint Assembly