HR: 0830h
AN: S31E-0802    [PDF]
TI: An Examination of Rayleigh Wave Phase Velocities, South Shetland Islands
AU: * Robertson Maurice, S D
EM: stacey.d.maurice@exxonmobil.com
AF: ExxonMobil Upstream Research Company, 3319 Mercer St., Houston, TX 77027 United States
AU: Wiens, D A
EM: doug@seismo.wustl.edu
AF: Washington University, One Brookings Dr. #1169, St. Louis, MO 63130 United States
AU: Lawrence, J F
EM: jfisher@levee.wustl.edu
AF: Washington University, One Brookings Dr. #1169, St. Louis, MO 63130 United States
AB: We examine the crustal and upper mantle structure of Bransfield Strait, the South Shetland Islands, and the Antarctic Peninsula using data from the Seismic Experiment in Patagonia and Antarctica (SEPA). We use Rayleigh wave phase velocity dispersion measurements from 20 teleseismic events to determine the interstation phase velocities at periods between 16 and 120 seconds. Maps of the velocities indicate crust with continental properties beneath the South Shetland Islands, the Antarctic Peninsula, and the area southwest of the Hero Fracture Zone. Thinner crust (less than 20 km thick) with backarc spreading mantle velocities lies within the Bransfield Basin proper. The seismic velocities indicate more established spreading in the northeastern portion of Bransfield Strait, and we see no evidence of anisotropy within the mantle.
DE: 7205 Continental crust (1242)
DE: 7218 Lithosphere and upper mantle
DE: 7230 Seismicity and seismotectonics
DE: 9310 Antarctica
SC: Seismology [S]
MN: 2003 Fall Meeting