Gravity Project

Australian National Gravity Database

The Australian National Gravity Database contains information on gravity surveys conducted in Australia and its offshore Territories. Gravity survey reports, data and maps are sourced from within Geoscience Australia, State and Territory governments, mineral and petroleum exploration companies, universities and overseas organisations. The Australian National Gravity Database currently contains information on more than 1.5 million point gravity observations taken in the course of more than 2300 surveys.

The density and distribution of gravity stations in Australia is shown on the Gravity Station Coverage Map - 1:250 000 Index Map and the Gravity Station Location Map - 1:10 Million Index Map. The gravity station locations shown on these maps are from surveys carried out since 1938 by Geoscience Australia and its predecessors, State and Territory geological surveys, private companies and universities. The regional gravity station spacing varies from approximately 11 kilometres over much of northern and western Australia to 1.5 kilometres in Victoria. The database also contains more detailed surveys with station spacing as close as 50 metres. Federal, State and Territory governments have recently funded systematic infill to provide improved coverage over areas of scientific or economic interest.

All open file gravity data in the Australian National Gravity Database are available to the public and may be obtained online free of charge. To download the complete database or data over a specific area of Australia use the Geophysical Archive Data Delivery System.

The consistency of the Australian National Gravity Database is controlled by a set of more accurately observed gravity stations called the Australian Fundamental Gravity Network (AFGN). These stations are in about 250 locations throughout Australia and can be identified using Geoscience Australia's AFGN web application.

To make full use of the gravity observations made in Australia and its offshore Territories these data must be collected into a single, consistent and reliable digital repository for the benefit of all Australians. This objective is being achieved through Geoscience Australia's Continental Geophysics project in a cooperative arrangement between Geoscience Australia, the State and Northern Territory Geological Surveys and mineral and petroleum exploration companies. The Continental Geophysics project will check and integrate data from all sources including companies submitting data to the Australian National Gravity Database.

Australian Fundamental Gravity Network

The Australian Fundamental Gravity Network (AFGN) consists of about 900 documented gravity base stations situated at about 250 locations throughout Australia and its Territories. This network provides the datum for gravity surveys conducted in Australia and the surrounding oceans and allows these surveys to be tied together in a consistent and accurate manner. Each of these stations has been measured to a greater precision than is considered normal for exploration survey stations. Most of the stations have been measured using two or more relative gravity meters with measurements taken at the station on two or more occasions. All of the stations in the network that were established in this way have been linked to create a consistent framework to which all other gravity surveys can be related. In recent years, this network has been augmented with stations established using a portable absolute gravity meter.

Selected stations from the original relative network have been occupied with the portable absolute gravity meter and the whole network has been adjusted to these absolute measurements. These new absolute gravity stations and the subsequent adjustment of the AFGN resulted in the redefinition of the Australian Gravity Datum from the Isogal84 datum, which was defined in 1984, to the Australian Absolute Gravity Datum 2007 (AAGD07).

Gravity values and descriptions of individual Fundamental Gravity Network stations can be obtained via the AFGN Web Application. These were previously available through the now superseded Online GIS.

As many of these stations are visited infrequently, please forward any information about their status to minerals@ga.gov.au so the station descriptions can be updated.