A seismic velocity survey was carried out in Associated Freney Oilfields Nerrima No. 1 Bore by the Bureau of Mineral Resources on the 10th August 1955. The well is situated on the Nerrima Dome in the Fitzroy Basin, W.A. Some trouble was experienced with cable breaks for the shallow part of the hole, but in general it was possible to recognise the true formation break. Average measured velocities ranged from 8000 ft/sec near the top to 12,200 ft/sec for the total depth of the bore.

Following a gravity survey of the Perth Basin in 1951-52 (Thyer and Everingham, 1956), in which it was indicated that a sedimentary thickness of about 35,000 ft was probably present in the Perth Basin, several seismic traverses were surveyed across the Basin. This Record deals with one such reflection traverse which was surveyed between Quindalup and Donnybrook. The purposes of the survey were to find the thickness and dip of the sediments and to discover any faulting or folding within them. Results of the survey were inconclusive regarding the depth to basement but indications are that it is at least 8000 ft in the deepest part of the B,sin along this traverse. The sediments appear to be folded and faulted. There is evidence for the existence of a major fault east of the Dunsborough Fault, and the existence of the Whicher Fault was tentatively confirmed.

In July and August 1957 an experimental seismic survey was done in the Oodnadatta area of the Great Artesian Basin. The purposes of the survey were to find whether reflections could be recorded from beneath duricrust, a siliceous surface deposit, and whether structures mapped by surface geological methods persist with depth. Reflections were recorded from beneath the duricrust using shallow pattern holes and six geophones per trace; the sub-surface structure was mapped with reasonable accuracy. In areas where the duricrust is eroded, reflections of fair quality were obtained using a single shot-hole and six geophones per trace. A seismic reflection traverse across the Oodnadatta anticline indicated that the structure was present in a horizon which corresponds to the top of the artesian aquifer at a depth of about 1000 ft below datum (400 ft above MSL). The seismic results indicated that the anticline was of smaller relief than had been e stimated from surface mapping. There was a change from fair-quality persistent reflections at shallow depths to poor-quality less numerous reflections with sporadic dips at greater depths; this probably represents the base of the Cretaceous. The greatest depth from which Cretaceous sediments were recorded was about 2350 ft below datum. Reflection depths computed by seismic methods correspond closely with lithological boundaries, and in particular the base of the Cretaceous sediments, encountered in the Santos No. 1 bore. The results of a refraction traverse on the crest of the Oudnadatta anticline show the presence of a 'basement' refractor with a velocity of 13,900 ft/sec at a depth of about 1245 ft below datum. There is slight evidence of a refractor with a substantially higher velocity at about twice this depth. The 'basement' velocity of 13,900 ft/sec is consistent with the assumption that there is a pre-Cretaceous layer between the Cretaceous sediments and the Precambrian basement complex.

A reconnaissance seismic survey was made in the area of Quilpie and Et.omanga in south-western Queensland. Traverses crossed the Harkaway, Pinkilla, and Tallyabra Domes. Reflection horizons were correlated with horizons within the Mesozoic sediments, and one persistent reflection was correlated with a horizon near the top of the Palaeozoic sediments. A thickness of sediments of up to 15,000 ft, including up to 11,000 ft of Palaeozoic rocks, was indicated on the flanks of the Harkaway and Pinkilla Domes. Results were compared with existing gravity data. Suggestions of faulting are based on seismic and gravity evidence taken together and also on gravity evidence alone in locations not covered by the seismic work.

On 30th March 1960, a seismic velocity survey was made in the A.A.O. Timbury Hills No. 2 bore, jointly by the Bureau of Mineral Resources and Associated Australian Oilfields N.L. The bore had been drilled to a depth of 4400 ft and was surveyed to a depth of 4304 ft below the rotary table. There remains a doubt whether the breaks recorded on the well geephone were, in fact, cable breaks, particularly between 2300 and 3305 ft below the rotary table. The interpretation has boon made with the belief that true breaks wore recorded. Average and interval velocities were computed and are acceptable geologically. Sandstones, particularly cemented ones, have Renerally higher velocities than shale. The average velocity of the Mesozoic sequence is about 9800 ft/sec. A velocity of 17,980 ft/sec was measured at the bottom of the bore and corresponds to the Timbury Hills Formation of unknown age. The Moolayember Shale has a low velocity calculated as 8360 ft/sec.

The Bureau of Mineral Resources Seismic Party No. 2 conducted a survey from 15th May to 25th August 1961 in the Amadeus Basin. Reflection and refraction traverses were shot at intervals, along or near the Alice Springs/Port Augusta railway line, from Polhill in the north to Finke in the south. In broad terms the object of the survey was to obtain across the Amadeus Basin a north-south seismic cross-section that would aid in investigating the stratigraphic cross-section and structural relations especially on the southern margin of the Basin. Access and drilling problems caused the progress of the survey to be slow. The statistics of the operation are included in three appendices. During the course of the seismic survey, the Bureau also made gravity surveys covering the area; gravity-meter readings were made along all seismic traverses.

During 1961 in the southern part of the Surat Basin a seismic party from the Bureau of Mineral Resources surveyed two main traverses by means of seismic reflection and refraction methods; the first was in an east-west direction between Yelarbon and St George and the second was in a north-south direction between Meandarra and Nome. The main purposes of the survey were to find whether the Bowen Basin Permian sediments extend as far south as the latitude of Goondiwindi and whether the Bowen Basin in Queensland and the Sydney Basin in New South Wales formed a continuous region of sedimentation during the Permian period. The east-west seismic traverse indicated a trough of sediments of greatest thickness,tabout 14,800 ft beneath Toobeah; the trough is bounded on the eastorn side at Goondiwindi by a fault down-thrown more than 7000 ft to the west and is bounded on the western side by a series of step.-faults beneath Bungunya and Talweod. The results along the north-south traverse indicated that the trough beneath Meandarra, which represents the southern extension of the Bowen Basin, continues south to Toobeah. The nature of the link, if any, between the Bowen Basin and the Sydney Basin was not established. On the eastern side of the Surat Basin, seismic results indicated that the rocks beneath the Mesozoic sediments are stratified and probably metamorphic. A shelf area between Talweod and St George has about 6000 ft of sediments above a Drobablo metamorphic 'basement'. An anticlinal structure with a dip-reversal of about 1000 ft throw was located between Goondiwindi and Toobeah.

Ice thickness measurements were made in 1961 by seismic methods on a line southward from S-2, a glaciological station 50 miles east-south-east of Wilkes Base, Antarctica. The traverse constituted the first year's work of a three-year programme. The results showed that the rock underlying the ice dips below sea level at a point between 20 and 40 miles south of S-2. It remains below sea level at all the locations occupied to the south, as far as 280 miles south of S-2, where the rock surface is again above sea level. The main feature is a valley disclosed in the rock formation between 40 and 80 miles south of S-2. Midway between these two points the rock lies at approximately 7500 ft below sea level. The positions of the Totten Glacier and the John Quincy Adams Glacier suggest that the valley may have been responsible for their formation.

35% coverage east F55/B1-41 Contour interval: 10

F55/B1-38 Contour interval: 5