Australian National Geophysical Data Collection

Brief description

Geoscience Australia is the custodian of the most comprehensive publicly available Australian airborne magnetic, gamma-ray, seismic, electromagnetic and gravity data sets. The airborne geophysics data set contains approximately 34 million line kilometres of data, which, at current prices, would cost approximately $197 million to acquire. The gravity data set contains more than 1.57 million reliable onshore stations gathered during more than 1800 surveys. The collection also includes a large number of seismic surveys from Australia's offshore basins. The onshore component of this data set was previously approved for RDSI for 8 TB. This proposal extends the collection to 150TB. The data types and access methods for the Offshore and Onshore data are identical Certain holdings are additionally hosted at the NCI (see downloads)

Lineage

Maintenance and Update Frequency: asNeeded

Statement: Geophysical data for these surveys are available to the public either through Geoscience Australia (GA), or through the relevant State/Territory Geological Surveys. They comprise more than 34 million line kilometres of mainly total magnetic intensity and gamma-ray spectrometric data. Land elevation data derived from GPS recordings made during airborne magnetic and gamma-ray spectrometric surveys, and electromagnetic data are also available for some areas. The surveys usually cover one or more 1:250 000 Sheet areas. Prior to 1990 most of the surveys had a flight line spacing of 1,500 m or more and many were conducted as part of the Bureau of Mineral Resources (BMR - the forerunner of the Australian Geological Survey Organisation (AGSO)) first pass airborne geophysical reconnaissance of Australia. From 1990 surveys have usually been conducted employing flight line spacings of 400 m or closer. The surveys have been flown under a number of auspices. AGSO (the forerunner of GA)/BMR used its own aircraft between 1951 and 1999. Surveys have also been conducted by airborne geophysical companies operating under contract to GA and State and Territory Geological Surveys, either separately or in joint projects. A number of other surveys, carried out for the private sector, have been purchased or acquired by GA, some under the Petroleum Search Subsidy Act (PSSA). A few of the surveys were conducted under the Petroleum Submerged Lands Act (P(SL)A). The airborne geophysical data collected by government surveys are held in GA's National Airborne Geophysical Database (NAGD). State and Territory geological surveys hold the data pertaining to each State or territory. The specifications of all surveys in the NAGD are held in an Index of Airborne Geophysical Surveys.

Notes

Purpose
The geophysical data sets have wide application to research and educational institutions, government agencies, and industry. So far the data has mainly been used by industry and some of the formats and many of the programs used to process the data are mainly commercial. The research community to date has not been able to fully access the data and has not had access to tools to process it. The VGL project has opened up open source opportunities to process the data and it is hoped that the research community will find many new uses for this data set and will develop more open source tools to process it. The seismic survey data has particular value in characterising the subsurface, since it can be calibrated to wells, samples and other geophysical data sets. Making this data available to the research community will enable the development of new techniques for predicting porosities and rock properties, automating the identification of seismic facies packages and comparing this with forward modelling. This collection is relevant to the National Strategic Research Priorities that are addressing the societal challenges for Lifting Productivity and Economic Growth and Managing our Food and Water Assets.