Site selection for Site 1164 was based on a SCS survey conducted during the R/V Melville cruise Sojourner 5 in 1997. A 31-min SCS and 3.5-kHz PDR survey was conducted on the approach to Site 1164 (JOIDES Resolution [JR] SCS line S12; Fig. F28) to ensure the correct site location by comparing the GPS navigated SCS data with the previous SCS image and to verify sediment thickness. The ship's average speed was 6.3 kt. The water gun was triggered at a shot interval of 12 s, equivalent to ~39 m at 6.3 kt. Site 1164, with a water depth of 4809.4 m, is at the GPS coordinates of prospectus site AAD-33a (AAD = Australian Antarctic Discordance) at a position corresponding to shotpoint 136 of seismic profile S12. Note that the navigation data file is offset from seismic records by 17 shots because of a fault during the survey. The shot numbers were counted sequentially, but the navigation data were reset (i.e., shotpoint 136 on record shows as shotpoint 119 in the data). Sediment cover was estimated from 6.48 to 6.63 s in two-way traveltime, equivalent to 150 m (Fig. F29). We washed through 138.5 m of sediment in Hole 1164A before basement was reached, whereas in Hole 1164B, ~200 m southwest of Hole 1164A, we drilled through 150.4 m of sediment.