Friday, 31 August 2007
5.PS-134

"Unconsolidated Sediments at the Bottom of Lake Vostok from Seismic Data"

Irina Filina1, Valery Lukin2, Valery Masolov3, and Donald Blankenship1. (1) Institute for Geophysics, The University of Texas at Austin, 10110 Burnet Rd., Bldg. 196, Austin, TX 78759, (2) Russian Antarctic Expedition, 38 Bering Str., Saint Petersburg, Russia, (3) Polar Marine Geological Research Expedition, 24 Pobeda Str., Saint Petersburg, Russia

Four seismograms acquired in different parts of Lake Vostok were analyzed. Three different hypotheses were tested for the origin of secondary seismic reflections at the bottom of Lake Vostok. The results show that some of the reflections, but not all of them, are consistent with the hypothesis of a gently sloping (< 2 degrees) non-flat lake bottom. The rest of the reflections were tested as side echoes, but this was rejected because of unreasonably steep slopes (at least 8 degrees) at the lake bottom. The hypothesis that is the most compatible with all seismograms is the presence of a layer of unconsolidated sediments at the bottom of Lake Vostok. The modeling suggests the presence of a two hundred meters thick sedimentary layer with the seismic velocity of 1700 -1900 m/sec in the southern and middle parts of the lake. The sedimentary layer thickens to ~350 m in the northern basin.

[Manuscript]

See more of Coffee break and poster viewing: 5.PS Ice history, ice dynamics, paleoceanography, and geodetic/geophysical observations
See more of General Submissions

See more of The 10th International Symposium on Antarctic Earth Sciences (Aug. 26 to Sept 1, 2007)