A new airborne survey of metropolitan Melbourne and eastern Victoria, designed to measure extremely subtle differences in gravity, will have big benefits for all Victorians.
The Earth’s gravitational field varies slightly from place to place due to the density of rocks below the surface and distance from the centre of the Earth. Collecting a consistent data set of gravity variations across Victoria has several applications, including mapping and resource management.
Australia is shifting north a few centimetres every year because of the dynamic plate tectonic movement of the Earth. New data will update measurements from Global Position Systems (GPS) to allow Victorians to accurately locate features marked on our maps.
Improved GPS positioning is important to economic activities that increasingly rely on accurate GPS such as for modern farming operations, infrastructure design and construction, land management and recreational activities.
The new data will advance the geoscience that assists the Victorian Government to manage its infrastructure and natural hazards. It will also support the state’s resources sector, which could aid regional jobs and economic growth.
The data will also support Geoscience Australia’s Positioning Australia program, which will incorporate Victoria’s data into its national gravity model and use it to improve the national height reference system.
The survey is expected to commence in late 2020. A fixed wing aircraft carrying the specialist measuring equipment will fly between 150 and 300 meters above ground, in parallel lines 500 meters to 2 kilometers apart.
Approximately 100,000 square kilometers will be flown, collecting data from the Great Ocean Road to the state’s eastern border with NSW, around Melbourne, the high country and Gippsland.
Airborne gravity surveys result in minimal disturbance to land users and the environment and were safely completed across southwest Victoria and the Bendigo region in 2019.