These notes deal with a brief experimental seismic survey undertaken by the Bureau of Mineral Resources for the Victoria Railways. The object of the survey was to determine whether the seismic refraction method was suitable for subsurface exploration in the area between Dynon and Footscray Roads, West Melbourne. The information desired by the Railways was concerned with the existence or otherwise of a "foundation" rock capable of supporting constructions associated with railway sidings and marshalling yards. Records of seismic refractions were obtained along three traverses.

Various aspects of isostasy concept are intimately linked to estimation of the elastic thickness of lithosphere, amplitude of mantle-driven vertical surface motions, basin uplift and subsidence. Common assumptions about isostasy are not always justified by existing data. For example, refraction seismic data provide essential constraints to estimation of isostasy, but are rarely analysed in that respect. Average seismic velocity, which is an integral characteristic of the crust to any given depth, can be calculated from initial refraction velocity models of the crust. Geoscience Australia has 566 full crust models derived from the interpretation of such data in its database as of January 2012. Average velocity through velocity/density regression translates into average density of the crust, and then into crustal column weight to any given depth. If average velocity isolines become horizontal at some depth, this may be an indication of balanced mass distribution (i.e., isostasy) in the crust to that depth. For example, average velocity distribution calculated for a very deep Petrel sedimentary basin on the Australian NW Margin shows no sign of velocity isolines flattening with depth all the way down to at least 15 km below the deepest Moho. Similar estimates for the Mount Isa region lead to opposite conclusions with balancing of average seismic velocities achieved above the Moho. Here, we investigate average seismic velocity distribution for the whole Australian continent and its margins, uncertainties of its translation into estimates of isostasy, and the possible explanations for misbalances in isostatic equilibrium of the Australian crust.

A multicomponent seismic survey using an IVI MiniVib as a source was carried out to assist in mapping of fracture porosity in shear zones in areas of dryland salinity for the School of Biological, Earth and Environmental Sciences (UNSW). The survey obtained a set of three dimensional, three component data at two sites near Spicers Creek, some 45km east of Dubbo. The acquisition was undertaken by Australian National Seismic Imaging Resource (ANSIR) from the 5th to the 12th April 2003 with the assistance of staff from UNSW. The objectives of this seismic survey are: 1. Develop quantitative measure of azimuthal anisotropy of P- and S-waves using refracted head wave amplitudes. 2. Determine the relative effects of lithological fabric and fracture porosity on P- and S-wave anisotropy factors. 3. Determine quantitative relationships between azimuthal anisotropy and fracture porosity. 4. Measure the horizontal and vertical variability of the fracture porosity in the fracture zones which control the discharge of saline groundwater and the occurrence of dryland salinity at the three experimental sites in the Spicers Creek Catchment. 5. Develop cost-effect field techniques for 3D - 3C (three dimensional - three component) shallow seismic refraction surveys for geotechnical, environmental and groundwater applications. Raw data for this survey are available on request from clientservices@ga.gov.au

Bureau of Mineral Resources conducted a seismic refraction survey during February 6th and March 5th, 1951. This survey aimed to resolve the shallow structure on the Comet anticlinal structure, 60 miles north of Rolleston for the oil exploration purpose.

The seismic survey made by the Geophysical Section of the Bureau of Mineral Resources to assist in the search for oil in the Carnarvon (North-West) Basin of Western Australia. The seismic field work in the Carnarvon Basin was confined to one field season, i.e., from April to December 1951, and consisted of surveys on the Capa Range and Giralia Anticlines. Both refraction and reflection methods were used. The purpose of the seismic work was to determine if the structures at surface extended to depth and thus establish if a suitable site for a deep exploration drill hole exist. The seismic work has shown that seismic methods are applicable in the investigation of possible oil-bearing struotures in the Carnarvon Basin. It is clear from the results obtained on the Giralia Anticline, that investigation with a view to tile selection ot deep drilling sites cannot be carried out thoroughly without seismic surveys of selected areas.

A reconnaissance seismic reflection and refraction survey in the East Otway Basin, Victoria, was carried out by the Bereau of Mineral Resources from mid-February to mid-June 1967. The objective of the survey was to determine whether the gravity low areas of the Torquay Embayment and Port Phillip Sub-Basin in the eastern part of the Otway Basin contain thick Cretaceous sediments like those which has shown potential hydrocarbon source and reservoir characteristics in the western part of the Otway Basin. Nine reflection and five refraction traverses were recorded in the gravity low areas of the Barwon Trough and Port Phillip Sub-basin. Single-coverage reflection results of variable quality were obtained. Evidence for the presence of Tertiary section is provided by shallow reflections of good to fair quality, but the evidence for Cretaceous sediments is tenuous because of the poor quality of the deeper reflections, some of which may be multiples. The presence of several faults, onlappings and pinch-outs is also indicated. The refraction results are considered unreliable because of the difficulty of interpreting the discontinuous profiles and because of the mapped and suspected faults and pinch-outs in the sections.

An experimental seismic survey was conducted at Surat, Queensland, on behalf of the Australisa Oil and Gas Corporation Limited during a five week period from May 28th to July 2nd. 1958. The area lies within the southeastern portion of the Great Artesian. Basin on Authority to Prospect No. 36P and, sel the evidence of numerous bores near Roma, and a few other scattered bore logs, is considered to contain sediments suitable for the generation and accumulation of hydrocarbons in possible, economic vantities. A local geological survey by the Australian Oil & Gas Corporation suggested a structure of considerable dimensions - the 'Weribone Uplift' - which, if substantiated, would provide a promising location for a stratigraphic test bore. The experimental survey conducted by the Bureaushowed that useful results could be obtained throughout the area by conventional methods of reflection and refraction shooting. The reflection shooting indicated a fairly uniform sedimentary section with generally flat-lying beds and a probable total thickness of 7,000 to 8,000 feet. The refraction work recorded several velocities: including one near 19,000 f/s which is assumed to be a basement velocity. Depths measured to this high Velocity refractor support the estimate of the thickness of sediments made from the reflection cross-section and indicate 4 south component of dip of about 40 ft. per mile across the area surveyed. Neither the reflection nor the refraction work gave any evidence for the existence of the 'Weribone Uplift'. However, the more northerly refraction traverse indicated a local component of north dip at basement depth, and a single reflection record shot along that traverse suggested a substantial thickening of the deeper sediments towards the north. Insufficient seismic work was done to estimate the northwards extent of this dip. Such limited evidence might well indicate a purely local irregularity in basement topography. On the other hand, the north dip could be extensive, and therefore structurally significant. Any further seismic work contemplated in this area should be directed, in the first instance, towards checking this possibility.

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.

In October and November 1959 a seismic party from the Bureau of Mineral Resources carried out a seismic survey in the Surat Basin, Queensland at the request of Australian Oil and Gas Corporation Ltd. A traverse extending from Surat eastward to within 10 miles of Tara was shot in five-mile sections of continuous reflection profiling with approximately five-mile intervals between the sections.^In addition two refraction traverses were shot near Surat to record velocities and depths of as many horizons as possible. Reflections were of fair to good quality throughout the survey and it was possible to correlate bands of reflections from one five-mile section to the next with considerable certainty. Over most of the traverses four reflecting horizons were followed, and in a few places reflections were obtained from a still deeper fifth horizon. The reflection survey revealed a wide basin between Surat and Cabawin (about 70 miles east of Surat), with its maximum thickness of sediments under Meandarra. The sediments there appear to be at least 19,000 ft thick. A marked anticline was discovered near Cabawtin. The refraction survey, using the "Depth Probing" method, revealed a refractor with a calculated velocity of 20,180 ft/sec situated about 1000 ft below the fourth reflecting horizon.

An experimental seismograph survey was carried out near Heywood in the Western District Basin, south-western Victoria, during November and December, 1956 by the Bureau of Mineral Resources, Geology and Geophysics. The work was requested by Frome-Broken Hill Pty. Ltd. and was intended primarily to ascertain if reflections from deoper sediments could be recorded through a surface layer of basalt which covers considerable areas in the Western District of Victoria. Several short traverses were shot during the survey at places where a variety of surface conditions for seismic exploration could be tested. Pattern and air-shooting techniques were tried as well as the conventional single shot-hole technique. Good reflections were recorded from depths down to eleven thousand feet in areas where there was no basalt. Some apparent reflections of poor quality were recorded at times as great as 5 seconds after the shot was fired. An attempt has been made to correlate the reflections with stratigraphic horizons. Reflections were obtained from strata beneath a basalt cover in some places when explosive charges were fired in single shot holes; reflection quality was improved when pattern and air-shooting techniques were used.It was not possible to record reflections through a cover of tuff containing basalt bands on the slopes of Mt. Clay. Pattern and air-shooting were tried unsuccessfully. Sub-surface information in the Heywood area is obtainable by seismic exploration and techniques for gaining the best information from the seismic method are discussed.