AIM: The 1992 Western Atlas Seismic Survey programme was aimed primarily at confirming the closure of the Investigator strong lead, a large, complex Lower Cambrian carbonate play situated at the southern end of the Marsden Trend, and secondly was intended to delineate possible northward extensions of the latter, regionally important horst-like basement trend. Accordingly, a comprehensive regional grid was laid out over the deeper water part of the Gulf (i.e. > 6-9 fathoms depth shelf break) on lines bearing at approximately 150 degrees and 65 degrees True. This programme joins to the 1986 SADME/GSI offshore survey grid on which the Investigator lead structural mapping had been based. METHODS: Survey dates: 7 - 14/7/92. Energy source: Tuned airgun array. CDP coverage: 6000%. Recording mode: 240 channel digital - LRS 16A Kiloseis streamer system. SP interval: 26.67 metres, group interval: 13.33 metres. RESULTS: 18 lines totalling 703 line km were acquired by the Western Geophysical M/V Western Atlas, and processed both by Alvin R. Hosking in Melbourne, Vic. and by Western Geophysical in Denver, Colorado. Only basic geophysical data for this survey is available while the related PELs remain in force - interpretive data will be released after licence relinquishment.