Precise positioning gives Australia an independent, national capability

Australian researchers now have access to crucial new information about Earthquake risks and precise movements of our continent thanks to AuScope’s Geospatial project known as the Very Long Baseline Interferometry (VLBI) network. With funding from the AuScope the project has constructed a network of three radio-telescopes in: Hobart, Tasmania; Yarragadee in Western Australia; and Katherine in the Northern Territory.

The radio-telescopes make extremely precise measurements; within an accuracy of one millimetre of their location in reference to the position of quasars in outer space.

Prior to AuScope’s Geospatial Infrastructure investment Australia had only one out-dated telescope in Hobart, and could only measure change at one point on the continent relative to stations in other countries such as South Africa and Japan.

This new network of three radio-telescopes allows Australian researchers to accurately measure the change in distances between points at vast distances across the continent. This gives unprecedented insights into deformation of the Australian tectonic plate.

Geoscience Australia’s Gary Johnston led the project and says Australia now has an independent, national capability.

“Australia had been poorly observed, along with much of the Southern Hemisphere. We already knew the Australian plate was fast-moving, heading north east at the rate of about seven centimetres per year and it was assumed there was very little deformation within our plate; the VLBI network has already shown that is not the case.”

Johnston gave the example of a 2004 earthquake near Macquarie Island. “We can now see the effects of that earthquake are still spreading up the east coast, and the distance between Hobart and Canberra has lengthened by about one centimetre in that time.

“It might not sound like much, but industries, like mining or construction, that rely on GPS will be affected unless we make a compensating adjustment.”

Already VLBI information was yielding insights into current day geological processes that could have important implications for understanding and managing earthquake hazards.

“The very existence of the north-south orientated Flinders Ranges tells us there should be east-west compression, but all the geodetic and seismic data before VLBI indicated this was not present. We will now be able to solve these puzzles and understand how deformation can occur without seismic events. More importantly, we will be able to identify parts of Australia where stresses are building that were not previously recognised.”

Caption: AuScope’s 12 metre radio-telescope at Katherine in the Northern Territory.

Case Study : National capability

Category: Geospatial Framework & Earth Dynamics