Australia is drifting northward at a rate of about 7 centimeters (just under 3 inches) per year, making it the fastest-moving continent on the planet. This movement is caused by the Indo-Australian tectonic plate, which carries not only mainland Australia but also Tasmania, parts of New Guinea, New Zealand, and regions of the Indian Ocean basin. By comparison, most continents move at an average rate of about 1.5 centimeters (0.6 inches) per year. This speed means Australia shifts as quickly as human hair and fingernails grow, highlighting how dynamic the Earth’s surface truly is.
The Science Behind Tectonic Shifts
Tectonic shift refers to the movement of the plates that make up Earth’s crust. The planet’s surface is divided into roughly a dozen major and several minor plates, which fit together like pieces of a cracked shell. These plates rest on the hot, molten mantle beneath, and their movement is driven by heat generated from radioactive processes deep inside the Earth.
This movement causes plates to collide, pull apart, or slide past each other, reshaping the planet’s surface over millions of years. According to the National Oceanic and Atmospheric Administration (NOAA), the average movement of continents is about 1.5 centimeters per year, but certain areas like coastal California experience faster motion, explaining their frequent earthquakes.
How Australia’s Movement Affects Mapping and Technology
Australia’s steady movement has practical implications for mapping and location-based technology. The country used coordinates based on the Geocentric Datum of Australia 1994 (GDA94), but by 2017, this system had become out of alignment with the continent’s actual position by approximately 1.6 meters (5.2 feet). To address this, the Australian government introduced the Geocentric Datum of Australia 2020 (GDA2020).
Minister for Resources and Northern Australia Matt Canavan announced that “Australia’s coordinates have officially moved 1.8 metres northeast,” emphasizing the importance of updating the reference frame. This change enhances the accuracy of location data used in industries such as surveying, mobile location services, and emerging intelligent transport systems.
Geoscience Australia’s Role in Updating the Geodetic Framework
Geoscience Australia has played a leading role in implementing the GDA2020 update. Nick Brown, the project leader for GDA2020 at Geoscience Australia, explained that the updated coordinates reflect the projected position of the Australian continent as of 2020.
To support this transition, Geoscience Australia and the Intergovernmental Committee on Surveying and Mapping (ICSM) have developed technical manuals, online software tools like AUSPOS and AUSGeoid2020, and a web service to convert spatial data from the old GDA94 system to the new GDA2020 standard. These resources aim to help government agencies and spatial organizations update their data and maintain accurate mapping and positioning services across the country.
Australia’s continuous northward drift serves as a clear example of how Earth’s surface is in constant motion, requiring ongoing adjustments in scientific measurement and technology to keep pace.