AIM:Previous to the subject survey other Delhi-Santos reconnaisance reflection seismic work in the Moomba area had outlined a large, gently folded anticline. The drill site for Moomba 1 was based on this information. Drillstem tests run in this well revealed an accumulation of gas in the upper Permian. The Moomba 2 well was then drilled some 5 km away and it also tested gas in commercial quantities. A second, detailed survey was conducted over the Moomba Gasfield structure during June-July 1966, in order to provide a greater density of control on which to base calculation of gas reserves trapped within the structure and on which to base selection of future drill sites.METHODS: Survey dates: 19/6 - 23/7/66. Energy source: Dynamite. CDP coverage: 100%. Recording mode: 24 channel analogue - United model 24-9E recorder. SP interval: 804.7m; group interval: 67.0m.13 seismic lines totalling 158 line km were shot, including line MV tying to the Moomba 1 and 2 wells, and line MS transecting the structure E-W through Moomba 1. 212 gravity stations were also metered at shotpoints in the survey area.RESULTS:The Moomba structure is mapped as a relatively low relief anticline covering a large, generally circular area. The structure is separated from the Gidgealpa Field by a prominent N-S trending syncline. A NE-SW trending fault, downthrown to the north, is mapped in the southeastern portion of the survey area on the base of Mesozoic and base of Permian horizons. Closure against the upthrown side of this fault is contoured on both these horizons. Other, lesser faults are also noted at the base of Permian level. Very little or no pre-Permian data is apparent on record sections, except on those lines immediately surrounding the anticline. The additional gravity control has substantiated the existing gravity interpretation of the Moomba feature, but a residual/derivative analysis might further clarify the structure.